Media-Augmented Exercise Machines

NASA Astrophysics Data System (ADS)

Krueger, T.

2002-01-01

Cardio-vascular exercise has been used to mitigate the muscle and cardiac atrophy associated with adaptation to micro-gravity environments. Several hours per day may be required. In confined spaces and long duration missions this kind of exercise is inevitably repetitive and rapidly becomes uninteresting. At the same time, there are pressures to accomplish as much as possible given the cost- per-hour for humans occupying orbiting or interplanetary. Media augmentation provides a the means to overlap activities in time by supplementing the exercise with social, recreational, training or collaborative activities and thereby reducing time pressures. In addition, the machine functions as an interface to a wide range of digital environments allowing for spatial variety in an otherwise confined environment. We hypothesize that the adoption of media augmented exercise machines will have a positive effect on psycho-social well-being on long duration missions. By organizing and supplementing exercise machines, data acquisition hardware, computers and displays into an interacting system this proposal increases functionality with limited additional mass. This paper reviews preliminary work on a project to augment exercise equipment in a manner that addresses these issues and at the same time opens possibilities for additional benefits. A testbed augmented exercise machine uses a specialty built cycle trainer as both input to a virtual environment and as an output device from it using spatialized sound, and visual displays, vibration transducers and variable resistance. The resulting interactivity increases a sense of engagement in the exercise, provides a rich experience of the digital environments. Activities in the virtual environment and accompanying physiological and psychological indicators may be correlated to track and evaluate the health of the crew.

An EMG-Controlled Robotic Hand Exoskeleton for Bilateral Rehabilitation.

PubMed

Leonardis, Daniele; Barsotti, Michele; Loconsole, Claudio; Solazzi, Massimiliano; Troncossi, Marco; Mazzotti, Claudio; Castelli, Vincenzo Parenti; Procopio, Caterina; Lamola, Giuseppe; Chisari, Carmelo; Bergamasco, Massimo; Frisoli, Antonio

2015-01-01

This paper presents a novel electromyography (EMG)-driven hand exoskeleton for bilateral rehabilitation of grasping in stroke. The developed hand exoskeleton was designed with two distinctive features: (a) kinematics with intrinsic adaptability to patient's hand size, and (b) free-palm and free-fingertip design, preserving the residual sensory perceptual capability of touch during assistance in grasping of real objects. In the envisaged bilateral training strategy, the patient's non paretic hand acted as guidance for the paretic hand in grasping tasks. Grasping force exerted by the non paretic hand was estimated in real-time from EMG signals, and then replicated as robotic assistance for the paretic hand by means of the hand-exoskeleton. Estimation of the grasping force through EMG allowed to perform rehabilitation exercises with any, non sensorized, graspable objects. This paper presents the system design, development, and experimental evaluation. Experiments were performed within a group of six healthy subjects and two chronic stroke patients, executing robotic-assisted grasping tasks. Results related to performance in estimation and modulation of the robotic assistance, and to the outcomes of the pilot rehabilitation sessions with stroke patients, positively support validity of the proposed approach for application in stroke rehabilitation.

Only Some Are Dead Men Walking: Teaching about Race Discrimination and the Death Penalty

ERIC Educational Resources Information Center

Bordt, Rebecca L.

2004-01-01

This paper describes an experiential learning exercise I have used to teach race discrimination in my introductory and criminology courses. The exercise is designed to introduce students to the concept of non-conscious forms of racial bias, a form of race discrimination often difficult for students to grasp. Using a hypothetical criminal case,…

Effect of the Mandibular Orthopedic Repositioning Appliance (MORA) on Forearm Muscle Activation and Grasping Power during Pinch and Hook Grip.

PubMed

Lee, Sang-Yeol; Park, Yi-Jeong; Park, Hye-Min; Bae, Hae-Jin; Yu, Min-Ji; Choi, Hee-Won; Hwang, Na-Young

2014-02-01

[Purpose] This study verified the changes in muscle activities and grasping power during maximal isometric exercise of the forearm and masseter muscle with and without a mandibular orthopedic repositioning appliance (MORA). It also offers basic data for defining the correlation of function of hand with mouth. [Methods] EMG was used to measure masticatory muscle, flexor bundle and extensor bundle activities with or without MORA while subjects performed the hook grip and pinch grip. The measuring tool used for measuring grip strength was the same as that used for measuring pinch and hook strength. The subjects were 28 healthy young adults. [Result] Muscle activity and grasping power significantly increased when wearing the MORA. [Conclusion] The result indicates that wearing MORA can increase muscle activity and grasping power of forearm and masseter muscle. We think wearing MORA might help improve the function of the forearm because it activates the function of the masseter.

Improvement and Neuroplasticity after Combined Rehabilitation to Forced Grasping

PubMed Central

Ogata, Atsuko; Kawahira, Kazumi; Shimodozono, Megumi

2017-01-01

The grasp reflex is a distressing symptom but the need to treat or suppress it has rarely been discussed in the literature. We report the case of a 17-year-old man who had suffered cerebral infarction of the right putamen and temporal lobe 10 years previously. Forced grasping of the hemiparetic left upper limb was improved after a unique combined treatment. Botulinum toxin type A (BTX-A) was first injected into the left biceps, wrist flexor muscles, and finger flexor muscles. Forced grasping was reduced along with spasticity of the upper limb. In addition, repetitive facilitative exercise and object-related training were performed under low-amplitude continuous neuromuscular electrical stimulation. Since this 2-week treatment improved upper limb function, we compared brain activities, as measured by near-infrared spectroscopy during finger pinching, before and after the combined treatment. Brain activities in the ipsilesional sensorimotor cortex (SMC) and medial frontal cortex (MFC) during pinching under electrical stimulation after treatment were greater than those before. The results suggest that training under electrical stimulation after BTX-A treatment may modulate the activities of the ipsilesional SMC and MFC and lead to functional improvement of the affected upper limb with forced grasping. PMID:28265475

Microsoft kinect-based artificial perception system for control of functional electrical stimulation assisted grasping.

PubMed

Strbac, Matija; Kočović, Slobodan; Marković, Marko; Popović, Dejan B

2014-01-01

We present a computer vision algorithm that incorporates a heuristic model which mimics a biological control system for the estimation of control signals used in functional electrical stimulation (FES) assisted grasping. The developed processing software acquires the data from Microsoft Kinect camera and implements real-time hand tracking and object analysis. This information can be used to identify temporal synchrony and spatial synergies modalities for FES control. Therefore, the algorithm acts as artificial perception which mimics human visual perception by identifying the position and shape of the object with respect to the position of the hand in real time during the planning phase of the grasp. This artificial perception used within the heuristically developed model allows selection of the appropriate grasp and prehension. The experiments demonstrate that correct grasp modality was selected in more than 90% of tested scenarios/objects. The system is portable, and the components are low in cost and robust; hence, it can be used for the FES in clinical or even home environment. The main application of the system is envisioned for functional electrical therapy, that is, intensive exercise assisted with FES.

Microsoft Kinect-Based Artificial Perception System for Control of Functional Electrical Stimulation Assisted Grasping

PubMed Central

Kočović, Slobodan; Popović, Dejan B.

2014-01-01

We present a computer vision algorithm that incorporates a heuristic model which mimics a biological control system for the estimation of control signals used in functional electrical stimulation (FES) assisted grasping. The developed processing software acquires the data from Microsoft Kinect camera and implements real-time hand tracking and object analysis. This information can be used to identify temporal synchrony and spatial synergies modalities for FES control. Therefore, the algorithm acts as artificial perception which mimics human visual perception by identifying the position and shape of the object with respect to the position of the hand in real time during the planning phase of the grasp. This artificial perception used within the heuristically developed model allows selection of the appropriate grasp and prehension. The experiments demonstrate that correct grasp modality was selected in more than 90% of tested scenarios/objects. The system is portable, and the components are low in cost and robust; hence, it can be used for the FES in clinical or even home environment. The main application of the system is envisioned for functional electrical therapy, that is, intensive exercise assisted with FES. PMID:25202707

A Three Month Home Exercise Programme Augmented with Nordic Poles for Patients with Intermittent Claudication Enhances Quality of Life and Continues to Improve Walking Distance and Compliance After One Year.

PubMed

Oakley, C; Spafford, C; Beard, J D

2017-05-01

The objective of this study was to collect 1 year follow-up information on walking distance, speed, compliance, and cost in patients with intermittent claudication who took part in a previously reported 12 week randomised clinical trial of a home exercise programme augmented with Nordic pole walking versus controls who walked normally. A second objective was to look at quality of life and ankle brachial pressure indices (ABPIs) after a 12 week augmented home exercise programme. Thirty-two of the 38 patients who completed the original trial were followed-up after 6 and 12 months. Frequency, duration, speed, and distance of walking were recorded using diaries and pedometers. A new observational cohort of 29 patients was recruited to the same augmented home exercise programme. ABPIs, walking improvement, and quality of life questionnaire were recorded at baseline and 12 weeks (end of the programme). Both groups in the follow-up study continued to improve their walking distance and speed over the following year. Compliance was excellent: 98% of the augmented group were still walking with poles at both 6 and 12 months, while 74% of the control group were still walking at the same point. The augmented group increased their mean walking distance to 17.5 km by 12 months, with a mean speed of 4.2 km/hour. The control group only increased their mean walking distance from 4.2 km to 5.6 km, and speed to 3.3 km/hour. Repeated ANOVA showed the results to be highly significant (p = .002). The 21/29 patients who completed the observational study showed a statistically significant increase in resting ABPIs from baseline (mean ± SD 0.75 ± 0.12) to week 12 (mean ± SD 0.85 ± 0.12) (t = (20) -8.89, p = .000 [two-tailed]). All their walking improvement and quality of life parameters improved significantly (p = .002 or less in the six categories) over the same period and their mean health scores improved by 79%. Following a 12 week augmented home exercise programme, most patients with intermittent claudication continued to significantly improve their walking distance and walking speed at 1 year compared with normal walking. Quality of life and ABPIs improved significantly after only 12 weeks and it is postulated that the improvement in ABPI was due to collateral development. These results justify the belief that an augmented home exercise programme will be as clinically effective as existing supervised exercise programmes, with the added benefits of lower cost and better compliance. Funding for a multicentre trial comparing an augmented home exercise programme with existing supervised exercise programme is now urgently required. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Effects of augmented reality-based Otago exercise on balance, gait, and physical factors in elderly women to prevent falls: a randomized controlled trial.

PubMed

Lee, Jin; Yoo, Ha-Na; Lee, Byoung-Hee

2017-09-01

[Purpose] To determine the effect of augmented reality (AR)-based otago exercise on muscle strength, balance, and physical factors in falls of elderly women. [Subjects and Methods] Thirty subjects were randomly assigned to AR group (AR, n=10), yoga group (yoga, n=10), and self-exercise group (self, n=10). For 12 weeks, these groups were given lessons related to AR-based otago exercise including strengthening, balance training, or yoga three times a week (60 minutes each time) and self-exercise using elastic band exercise program. [Results] Knee flexion and ankle dorsiflexion strength were significantly improved in all three groups (AR, yoga, and self-exercise groups). Regarding balance, eye open center of pressure-x (EO CoP-x) was significantly decreased in AR group and yoga group. However, eye close CoP-x, eye open standard deviation-x (EO SD-x), and eye open height of ellipse (EO HoE) were only significantly decreased in AR group. AR group also showed meaningfully improved results in morse fall scale. [Conclusion] Augmented reality-based otago exercise can improve muscle strength, balance, and physical factors in elderly women to prevent falls.

An intervention program to promote health-related physical fitness in nurses.

PubMed

Yuan, Su-Chuan; Chou, Ming-Chih; Hwu, Lien-Jen; Chang, Yin-O; Hsu, Wen-Hsin; Kuo, Hsien-Wen

2009-05-01

To assess the effects of exercise intervention on nurses' health-related physical fitness. Regular exercise that includes gymnastics or aerobics has a positive effect on fitness. In Taiwan, there are not much data which assess the effects of exercise intervention on nurses' health-related physical fitness. Many studies have reported the high incidence of musculoskeletal disorders (MSDs) in nurses However, there has been limited research on intervention programs that are designed to improve the general physical fitness of nurses. A quasi-experimental study was conducted at a medical centre in central Taiwan. Ninety nurses from five different units of a hospital volunteered to participate in this study and participated in an experimental group and a control group. The experimental group engaged in a three-month intervention program consisting of treadmill exercise. Indicators of the health-related physical fitness of both groups were established and assessed before and after the intervention. Before intervention, the control group had significantly better grasp strength, flexibility and durability of abdominal muscles than the experimental group (p < 0.05). After the intervention, logistic regression was used to adjust for marital status, work duration, regular exercise and workload and found that the experimental group performed significantly better (p < 0.05) on body mass index, grasp strength, flexibility, durability of abdominal and back muscles and cardiopulmonary function. This study demonstrates that the development and implementation of an intervention program can promote and improve the health-related physical fitness of nurses. It is suggested that nurses engage in an exercise program while in the workplace to lower the risk of MSDs and to promote working efficiency.

A single exercise bout augments adenovirus-specific T-cell mobilization and function.

PubMed

Kunz, Hawley E; Spielmann, Guillaume; Agha, Nadia H; O'Connor, Daniel P; Bollard, Catherine M; Simpson, Richard J

2018-04-30

Adoptive transfer of virus-specific T-cells (VSTs) effectively treats viral infections following allogeneic hematopoietic stem cell transplantation (alloHSCT), but logistical difficulties have limited widespread availability of VSTs as a post-transplant therapeutic. A single exercise bout mobilizes VSTs specific for latent herpesviruses (i.e. CMV and EBV) to peripheral blood and augments their ex vivo expansion. We investigated whether exercise exerts similar effects on T-cells specific for a NON-latent virus such as adenovirus, which is a major contributor to infection-related morbidity and mortality after alloHSCT. Thirty minutes of cycling exercise increased circulating adenovirus-specific T-cells 2.0-fold and augmented their ex vivo expansion by ~33% compared to rest without altering antigen and MHC-specific autologous target cell killing capabilities. We conclude that exercise is a simple and economical adjuvant to boost the isolation and manufacture of therapeutic VSTs specific to latent and non-latent viruses from healthy donors. Copyright © 2018. Published by Elsevier Inc.

Evidence-based recommendations for the prescription of exercise for major depressive disorder.

PubMed

Rethorst, Chad D; Trivedi, Madhukar H

2013-05-01

Major depressive disorder (MDD) is a source of great disease burden, due in part to the limited accessibility and effectiveness of current treatments. Although current treatments are efficacious in a segment of the population with MDD, there is a clear need for alternative and augmentation treatment strategies. Exercise is one such alternative treatment option. Research has shown exercise to be efficacious as both a stand-alone and an augmentation therapy. As a result, exercise is now included in the American Psychiatric Association's treatment recommendations. The purpose of this article is to provide clinicians with a knowledge base to prescribe exercise to their patients. The authors describe the evidence supporting the use of exercise in the treatment of MDD, provide evidence-based recommendations for prescribing exercise, and address practical considerations related to prescribing exercise in real-world treatment settings.

Effects of long-term balance training with vibrotactile sensory augmentation among community-dwelling healthy older adults: a randomized preliminary study.

PubMed

Bao, Tian; Carender, Wendy J; Kinnaird, Catherine; Barone, Vincent J; Peethambaran, Geeta; Whitney, Susan L; Kabeto, Mohammed; Seidler, Rachael D; Sienko, Kathleen H

2018-01-18

Sensory augmentation has been shown to improve postural stability during real-time balance applications. Limited long-term controlled studies have examined retention of balance improvements in healthy older adults after training with sensory augmentation has ceased. This pilot study aimed to assess the efficacy of long-term balance training with and without sensory augmentation among community-dwelling healthy older adults. Twelve participants (four males, eight females; 75.6 ± 4.9 yrs) were randomly assigned to the experimental group (n = 6) or control group (n = 6). Participants trained in their homes for eight weeks, completing three 45-min exercise sessions per week using smart phone balance trainers that provided written, graphic, and video guidance, and monitored trunk sway. During each session, participants performed six repetitions of six exercises selected from five categories (static standing, compliant surface standing, weight shifting, modified center of gravity, and gait). The experimental group received vibrotactile sensory augmentation for four of the six repetitions per exercise via the smart phone balance trainers, while the control group performed exercises without sensory augmentation. The smart phone balance trainers sent exercise performance data to a physical therapist, who recommended exercises on a weekly basis. Balance performance was assessed using a battery of clinical balance tests (Activity Balance Confidence Scale, Sensory Organization Test, Mini Balance Evaluation Systems Test, Five Times Sit to Stand Test, Four Square Step Test, Functional Reach Test, Gait Speed Test, Timed Up and Go, and Timed Up and Go with Cognitive Task) before training, after four weeks of training, and after eight weeks of training. Participants in the experimental group were able to use vibrotactile sensory augmentation independently in their homes. After training, the experimental group had significantly greater improvements in Sensory Organization Test and Mini Balance Evaluation Systems Test scores than the control group. Significant improvement was also observed for Five Times Sit to Stand Test duration within the experimental group, but not in the control group. No significant improvements between the two groups were observed in the remaining clinical outcome measures. The findings of this study support the use of sensory augmentation devices by community-dwelling healthy older adults as balance rehabilitation tools, and indicate feasibility of telerehabilitation therapy with reduced input from clinicians.

Nitric oxide contributes to the augmented vasodilatation during hypoxic exercise

PubMed Central

Casey, Darren P; Madery, Brandon D; Curry, Timothy B; Eisenach, John H; Wilkins, Brad W; Joyner, Michael J

2010-01-01

We tested the hypotheses that (1) nitric oxide (NO) contributes to augmented skeletal muscle vasodilatation during hypoxic exercise and (2) the combined inhibition of NO production and adenosine receptor activation would attenuate the augmented vasodilatation during hypoxic exercise more than NO inhibition alone. In separate protocols subjects performed forearm exercise (10% and 20% of maximum) during normoxia and normocapnic hypoxia (80% arterial O2 saturation). In protocol 1 (n= 12), subjects received intra-arterial administration of saline (control) and the NO synthase inhibitor NG-monomethyl-l-arginine (l-NMMA). In protocol 2 (n= 10), subjects received intra-arterial saline (control) and combined l-NMMA–aminophylline (adenosine receptor antagonist) administration. Forearm vascular conductance (FVC; ml min−1 (100 mmHg)−1) was calculated from forearm blood flow (ml min−1) and blood pressure (mmHg). In protocol 1, the change in FVC (Δ from normoxic baseline) due to hypoxia under resting conditions and during hypoxic exercise was substantially lower with l-NMMA administration compared to saline (control; P < 0.01). In protocol 2, administration of combined l-NMMA–aminophylline reduced the ΔFVC due to hypoxic exercise compared to saline (control; P < 0.01). However, the relative reduction in ΔFVC compared to the respective control (saline) conditions was similar between l-NMMA only (protocol 1) and combined l-NMMA–aminophylline (protocol 2) at 10% (−17.5 ± 3.7 vs.−21.4 ± 5.2%; P= 0.28) and 20% (−13.4 ± 3.5 vs.−18.8 ± 4.5%; P= 0.18) hypoxic exercise. These findings suggest that NO contributes to the augmented vasodilatation observed during hypoxic exercise independent of adenosine. PMID:19948661

Closed-Loop Hybrid Gaze Brain-Machine Interface Based Robotic Arm Control with Augmented Reality Feedback

PubMed Central

Zeng, Hong; Wang, Yanxin; Wu, Changcheng; Song, Aiguo; Liu, Jia; Ji, Peng; Xu, Baoguo; Zhu, Lifeng; Li, Huijun; Wen, Pengcheng

2017-01-01

Brain-machine interface (BMI) can be used to control the robotic arm to assist paralysis people for performing activities of daily living. However, it is still a complex task for the BMI users to control the process of objects grasping and lifting with the robotic arm. It is hard to achieve high efficiency and accuracy even after extensive trainings. One important reason is lacking of sufficient feedback information for the user to perform the closed-loop control. In this study, we proposed a method of augmented reality (AR) guiding assistance to provide the enhanced visual feedback to the user for a closed-loop control with a hybrid Gaze-BMI, which combines the electroencephalography (EEG) signals based BMI and the eye tracking for an intuitive and effective control of the robotic arm. Experiments for the objects manipulation tasks while avoiding the obstacle in the workspace are designed to evaluate the performance of our method for controlling the robotic arm. According to the experimental results obtained from eight subjects, the advantages of the proposed closed-loop system (with AR feedback) over the open-loop system (with visual inspection only) have been verified. The number of trigger commands used for controlling the robotic arm to grasp and lift the objects with AR feedback has reduced significantly and the height gaps of the gripper in the lifting process have decreased more than 50% compared to those trials with normal visual inspection only. The results reveal that the hybrid Gaze-BMI user can benefit from the information provided by the AR interface, improving the efficiency and reducing the cognitive load during the grasping and lifting processes. PMID:29163123

Using "Arabidopsis" Genetic Sequences to Teach Bioinformatics

ERIC Educational Resources Information Center

Zhang, Xiaorong

2009-01-01

This article describes a new approach to teaching bioinformatics using "Arabidopsis" genetic sequences. Several open-ended and inquiry-based laboratory exercises have been designed to help students grasp key concepts and gain practical skills in bioinformatics, using "Arabidopsis" leucine-rich repeat receptor-like kinase (LRR…

Food-Dependent, Exercise-Induced Anaphylaxis: Diagnosis and Management in the Outpatient Setting.

PubMed

Feldweg, Anna M

Food-dependent, exercise-induced anaphylaxis is a disorder in which anaphylaxis develops most predictably during exercise, when exercise takes place within a few hours of ingesting a specific food. IgE to that food should be demonstrable. It is the combination of the food and exercise that precipitates attacks, whereas the food and exercise are each tolerated independently. Recently, it was demonstrated that exercise is not essential for the development of symptoms, and that if enough of the culprit food is ingested, often with additional augmentation factors, such as alcohol or acetylsalicylic acid, symptoms can be induced at rest in the challenge setting. Thus, food-dependent, exercise-induced anaphylaxis appears to be more correctly characterized as a food allergy syndrome in which symptoms develop only in the presence of various augmentation factors, with exercise being the primary one. However, additional factors are not usually present when the patient exercises normally, so ongoing investigation is needed into the physiologic and cellular changes that occur during exercise to facilitate food-induced anaphylaxis. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Control of a Robotic Hand Using a Tongue Control System-A Prosthesis Application.

PubMed

Johansen, Daniel; Cipriani, Christian; Popovic, Dejan B; Struijk, Lotte N S A

2016-07-01

The aim of this study was to investigate the feasibility of using an inductive tongue control system (ITCS) for controlling robotic/prosthetic hands and arms. This study presents a novel dual modal control scheme for multigrasp robotic hands combining standard electromyogram (EMG) with the ITCS. The performance of the ITCS control scheme was evaluated in a comparative study. Ten healthy subjects used both the ITCS control scheme and a conventional EMG control scheme to complete grasping exercises with the IH1 Azzurra robotic hand implementing five grasps. Time to activate a desired function or grasp was used as the performance metric. Statistically significant differences were found when comparing the performance of the two control schemes. On average, the ITCS control scheme was 1.15 s faster than the EMG control scheme, corresponding to a 35.4% reduction in the activation time. The largest difference was for grasp 5 with a mean AT reduction of 45.3% (2.38 s). The findings indicate that using the ITCS control scheme could allow for faster activation of specific grasps or functions compared with a conventional EMG control scheme. For transhumeral and especially bilateral amputees, the ITCS control scheme could have a significant impact on the prosthesis control. In addition, the ITCS would provide bilateral amputees with the additional advantage of environmental and computer control for which the ITCS was originally developed.

A Rehabilitation-Internet-of-Things in the Home to Augment Motor Skills and Exercise Training.

PubMed

Dobkin, Bruce H

2017-03-01

Although motor learning theory has led to evidence-based practices, few trials have revealed the superiority of one theory-based therapy over another after stroke. Nor have improvements in skills been as clinically robust as one might hope. We review some possible explanations, then potential technology-enabled solutions. Over the Internet, the type, quantity, and quality of practice and exercise in the home and community can be monitored remotely and feedback provided to optimize training frequency, intensity, and progression at home. A theory-driven foundation of synergistic interventions for walking, reaching and grasping, strengthening, and fitness could be provided by a bundle of home-based Rehabilitation Internet-of-Things (RIoT) devices. A RIoT might include wearable, activity-recognition sensors and instrumented rehabilitation devices with radio transmission to a smartphone or tablet to continuously measure repetitions, speed, accuracy, forces, and temporal spatial features of movement. Using telerehabilitation resources, a therapist would interpret the data and provide behavioral training for self-management via goal setting and instruction to increase compliance and long-term carryover. On top of this user-friendly, safe, and conceptually sound foundation to support more opportunity for practice, experimental interventions could be tested or additions and replacements made, perhaps drawing from virtual reality and gaming programs or robots. RIoT devices continuously measure the actual amount of quality practice; improvements and plateaus over time in strength, fitness, and skills; and activity and participation in home and community settings. Investigators may gain more control over some of the confounders of their trials and patients will have access to inexpensive therapies.

Demonstrating Kinematics and Newton's Laws in a Jump

ERIC Educational Resources Information Center

Kamela, Martin

2007-01-01

When students begin the study of Newton's laws they are generally comfortable with static equilibrium type problems, but dynamic examples where forces are not constant are more challenging. The class exercise presented here helps students to develop an intuitive grasp of both the position-velocity-acceleration relation and the force-acceleration…

Introducing AC Inductive Reactance with a Power Tool

ERIC Educational Resources Information Center

Bryant, Wesley; Baker, Blane

2016-01-01

The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance…

Effects of altitude and exercise on pulmonary capillary integrity: evidence for subclinical high-altitude pulmonary edema.

PubMed

Eldridge, Marlowe W; Braun, Ruedi K; Yoneda, Ken Y; Walby, William F

2006-03-01

Strenuous exercise may be a significant contributing factor for development of high-altitude pulmonary edema, particularly at low or moderate altitudes. Thus we investigated the effects of heavy cycle ergometer exercise (90% maximal effort) under hypoxic conditions in which the combined effects of a marked increase in pulmonary blood flow and nonuniform hypoxic pulmonary vasoconstriction could add significantly to augment the mechanical stress on the pulmonary microcirculation. We postulated that intense exercise at altitude would result in an augmented permeability edema. We recruited eight endurance athletes and examined their bronchoalveolar lavage fluid (BALF) for red blood cells (RBCs), protein, inflammatory cells, and soluble mediators at 2 and 26 h after intense exercise under normoxic and hypoxic conditions. After heavy exercise, under all conditions, the athletes developed a permeability edema with high BALF RBC and protein concentrations in the absence of inflammation. We found that exercise at altitude (3,810 m) caused significantly greater leakage of RBCs [9.2 (SD 3.1)x10(4) cells/ml] into the alveolar space than that seen with normoxic exercise [5.4 (SD 1.2)x10(4) cells/ml]. At altitude, the 26-h postexercise BALF revealed significantly higher RBC and protein concentrations, suggesting an ongoing capillary leak. Interestingly, the BALF profiles following exercise at altitude are similar to that of early high-altitude pulmonary edema. These findings suggest that pulmonary capillary disruption occurs with intense exercise in healthy humans and that hypoxia augments the mechanical stresses on the pulmonary microcirculation.

Learning While Exercising for Science Education in Augmented Reality among Adolescents

ERIC Educational Resources Information Center

Hsiao, Kuei-Fang; Chen, Nian-Shing; Huang, Shih-Yu

2012-01-01

Because of a shortage of physical exercise, concerns about adolescents have recently been raised in Taiwan. In educational environments where student exercise has been limited by scheduling constraints and the lack of physical exercise has become a vital problem, "learning while exercising" may be part of a possible solution. This study…

Potentiation of the NO-cGMP pathway and blood flow responses during dynamic exercise in healthy humans

PubMed Central

Limberg, Jacqueline K.; Malterer, Katherine R.; Kellawan, J. Mikhail; Schrage, William G.; Wilkins, Brad W.; Nicholson, Wayne T.; Eisenach, John H.; Joyner, Michael J.; Curry, Timothy B.

2017-01-01

Purpose Previous work has shown nitric oxide (NO) contributes to ~15% of the hyperemic response to dynamic exercise in healthy humans. This NO-mediated vasodilation occurs, in part, via increases in intracellular cyclic guanosine monophosphate (cGMP), which is catabolized by phosphodiesterase. We sought to examine the effect of phosphodiesterase-5 (PDE-5) inhibition on forearm blood flow (FBF responses to dynamic handgrip exercise in healthy humans and the role of NO. We hypothesized exercise hyperemia would be augmented by sildenafil citrate (SDF, PDE-5 inhibitor). We further hypothesized any effect of SDF on exercise hyperemia would be abolished with intra-arterial infusion of the NO synthase (NOS) inhibitor L-NG-monomethyl arginine (L-NMMA). Methods FBF (Doppler ultrasound) was assessed at rest and during 5 minutes of dynamic forearm handgrip exercise at 15% of maximal voluntary contraction under control (saline) conditions and during 3 experimental protocols: 1) oral SDF (n=10), 2) intra-arterial L-NMMA (n=20), 3) SDF and L-NMMA (n=10). FBF responses to intra-arterial sodium nitroprusside (NTP, NO donor) were also assessed. Results FBF increased with exercise (p<0.01). Intra-arterial infusion of L-NMMA resulted in a reduction in exercise hyperemia (17±1 to 15±1 mL/dL/min, p<0.01). Although the hyperemic response to NTP was augmented by SDF (Area under the curve: 41±7 vs 61±11 AU, p<0.01), there was no effect of SDF on exercise hyperemia (p=0.33). Conclusions Despite improving NTP-mediated vasodilation, oral SDF failed to augment exercise hyperemia in young, healthy adults. These observations reflect a minor contribution of NO and the cGMP pathway during exercise hyperemia in healthy young humans. PMID:28013386

Long-lasting effects of fluoxetine and/or exercise augmentation on bio-behavioural markers of depression in pre-pubertal stress sensitive rats.

PubMed

Schoeman, Jacobus C; Steyn, Stephanus F; Harvey, Brian H; Brink, Christiaan B

2017-04-14

Juvenile depression is of great concern with only limited treatment currently approved. Delayed onset of action, low remission and high relapse rates, and potential long-lasting consequences further complicates treatment and highlights the need for new treatment options. Studies reporting on long-lasting effects of early-life treatment have reported conflicting results, with the pre-adolescent period mostly overlooked. The anti-depressive effect of exercise, as a possible treatment option or augmentation strategy, is dependent on age and exercise intensity. We investigated the immediate (i.e. postnatal day 35 (PND35)) and lasting (PND60 to PND61) effects of pre-pubertal (PND21 to PND34) fluoxetine and/or exercise on bio-behavioural markers of depression and oxidative stress in stress sensitive Flinders Sensitive Line rats. Low, but not moderate, intensity exercise or 5, but not 10, mg/kg/day fluoxetine displayed anti-depressant-like properties at PND35. Pre-pubertal treatment with 5mg/kg/day fluoxetine or low intensity exercise exerted lasting anti-depressive-like effects into adulthood, whereas the combination of these two treatments did not. Furthermore, the combination of fluoxetine plus exercise reduced hippocampal BDNF levels as compared to exercise alone, which may explain the latter findings. In all treatment groups hippocampal SOD activity was significantly increased at PND61, suggesting an increased anti-oxidant capacity in adulthood. In conclusion, the data confirm the anti-depressant-like properties of both early-life fluoxetine and exercise in a genetic animal model of depression. However, optimal lasting effects of early-life interventions may require adjustment of antidepressant dose and/or exercise intensity to developmental age, and that a combination of antidepressant and exercise may not necessarily be augmentative. Copyright © 2017 Elsevier B.V. All rights reserved.

Effectiveness of Aerobic Exercise as an Augmentation Therapy for Inpatients with Major Depressive Disorder: A Preliminary Randomized Controlled Trial.

PubMed

Shachar-Malach, Tal; Cooper Kazaz, Rena; Constantini, Naama; Lifschytz, Tzuri; Lerer, Bernard

2015-01-01

Physical exercise has been shown to reduce depressive symptoms when used in combination with antidepressant medication. We report a randomized controlled trial of aerobic exercise compared to stretching as an augmentation strategy for hospitalized patients with major depression. Male or female patients, 18-80 years, diagnosed with a Major Depressive Episode, were randomly assigned to three weeks of augmentation therapy with aerobic (n=6) or stretching exercise (n=6). Depression was rated, at several time points using the 21-item Hamilton Depression Scale (HAM-D), Beck Depression Inventory (BDI) and other scales. According to the HAM-D, there were four (out of six) responders in the aerobic group, two of whom achieved remission, and none in the stretching group. According to the BDI, there were two responders in the aerobic group who were also remitters and none in the stretching group. The results of this small study suggest that aerobic exercise significantly improves treatment outcome when added to antidepressant medication. However, due to the small sample size the results must be regarded as preliminary and further studies are needed to confirm the findings.

Augmentation of Deglutitive Thyrohyoid Muscle Shortening by the Shaker Exercise

PubMed Central

Mepani, Rachel; Antonik, Stephen; Massey, Benson; Kern, Mark; Logemann, Jerilyn; Pauloski, Barbara; Rademaker, Alfred; Easterling, Caryn

2010-01-01

Earlier studies of the effect of 6 weeks of the Shaker Exercise have shown significant increase in UES opening and anterior excursion of larynx and hyoid during swallowing in patients with upper esophageal sphincter (UES) dysfunction, resulting in elimination of aspiration and resumption of oral intake. This effect is attributed to strengthening of the suprahyoid muscles, as evidenced by comparison of electromyographic changes in muscle fatigue before and after completion of the exercise regime. The effect of this exercise on thyrohyoid muscle shortening is unknown. Therefore the aim of this study was to determine the effect of the exercise on thyrohyoid muscle shortening. We studied 11 dysphagic patients with UES dysfunction. Six were randomized to traditional swallowing therapy and five to the Shaker Exercise. Videofluoroscopy was used to measure deglutitive thyrohyoid shortening before and after completion of assigned therapy regimen. Maximum thyrohyoid muscle shortening occurred at close temporal proximity to the time of maximal thyroid cartilage excursion. The percent change in thyrohyoid distance from initiation of deglutition to maximal anterior/superior hyoid excursion showed no statistically significant difference between the two groups prior to either therapy (p = 0.54). In contrast, after completion of therapy, the percent change in thyrohyoid distance in the Shaker Exercise group was significantly greater compared to the traditional therapy (p = 0.034). The Shaker Exercise augments the thyrohyoid muscle shortening in addition to strengthening the suprahyoid muscles. The combination of increased thyrohyoid shortening and suprahyoid strengthening contributes to the Shaker Exercise outcome of deglutitive UES opening augmentation. PMID:18685891

Varying Iron Release from Transferrin and Lactoferrin Proteins. A Laboratory Experiment

ERIC Educational Resources Information Center

Carmona, Fernando; González, Ana; Sánchez, Manu; Gálvez, Natividad; Cuesta, Rafael; Capdevila, Mercè; Dominguez-Vera, Jose M.

2017-01-01

Iron metabolism is an important subject of study for undergraduate students of chemistry and biochemistry. Relevant laboratory exercises are scarce in the literature but would be very helpful in assisting students grasp key concepts. The experiment described here deals with different iron release mechanisms of two protagonists in iron metabolism:…

Introducing AC inductive reactance with a power tool

NASA Astrophysics Data System (ADS)

Bryant, Wesley; Baker, Blane

2016-09-01

The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance is smaller than expected, they are asked to explain these observations using previously studied principles of magnetic induction. Exercises also introduce the notion of inductive reactance and impedance in AC circuits and, ultimately, determine self-inductance of the motor windings within the power tool.

Breathing mechanics during exercise with added dead space reflect mechanisms of ventilatory control.

PubMed

Wood, Helen E; Mitchell, Gordon S; Babb, Tony G

2009-09-30

Small increases in external dead space (V(D)) augment the exercise ventilatory response via a neural mechanism known as short-term modulation (STM). We hypothesized that breathing mechanics would differ during exercise, increased V(D) and STM. Men were studied at rest and during cycle exercise (10-50W) without (Control) and with added V(D) (200-600ml). With added V(D), V(T) increased via increased end-inspiratory lung volume (EILV), with no change in end-expiratory lung volume (EELV), indicating recruitment of inspiratory muscles only. With exercise, V(T) increased via both decreased EELV and increased EILV, indicating recruitment of both expiratory and inspiratory muscles. A significant interaction between the effects of exercise and V(D) on mean inspiratory flow indicated that the augmented exercise ventilatory response with added V(D) (i.e. STM) resulted from increased drive to the inspiratory muscles. These results reveal different patterns of respiratory muscle recruitment among experimental conditions. Hence, we conclude that fundamental differences exist in the neural control of ventilatory responses during exercise, increased V(D) and STM.

Duration and mechanisms of the increased natural cytotoxicity seen after chronic voluntary exercise in rats.

PubMed

Jonsdottir, I H; Johansson, C; Asea, A; Johansson, P; Hellstrand, K; Thorén, P; Hoffmann, P

1997-08-01

We have recently shown that in vivo natural cytotoxicity is enhanced after chronic exercise in spontaneously hypertensive rats (SHRs). In the present report, we have studied the duration of this augmentation and some possible mechanisms involved. Exercise consisted of voluntary running for 4-5 weeks, with the running distance ranging from 2.7-15.6 km day(-1) during the last week of running. In vivo cytotoxicity was measured as clearance of injected 51Cr-labelled YAC-1 lymphoma cells from the lungs. The in vivo natural cytotoxicity was increased in running SHRs, and also in SHRs that had their running wheel locked for 24 and 48 h prior to the experiment, and was still present after 96 h. The enhancement of in vivo cytotoxicity after 5 weeks of exercise was abolished after an acute injection of the beta-adrenergic receptor antagonist timolol (0.5 mg kg(-1) i.v.), indicating that catecholamines are involved in this augmentation. Interestingly, 24 h after the last exercise bout, the increased natural cytotoxicity could be blocked by timolol. The opioid receptor antagonist naloxone given subcutaneously for 7 days by osmotic pumps (6 mg kg(-1) h(-1)) could not reverse the increased in vivo cytotoxicity seen in the running SHRs, suggesting that opioid receptor mechanisms are not involved, or at least not the naloxone-sensitive mu-receptor. Natural immunity was not influenced by the histamine H2 receptor antagonist ranitidine, either in controls or in runners, indicating that the natural killer cell-regulatory effect of histamine is not present in SHRs and does not seem to be involved in the exercise-induced changes in natural immune function. We conclude that the augmentation of in vivo natural cytotoxicity after voluntary chronic exercise in rats is long-lasting and that the augmentation is partly mediated by beta-adrenergic receptors.

An investigation of the tri-bar gripping system on isometric muscular endurance.

PubMed

Drury, Daniel G; Faggiono, Heath; Stuempfle, Kristin J

2004-11-01

Recently, a new product called the Tri-Bar has been introduced as an alternative to the standard round weightlifting bar. The Tri-Bar has the same weight, length, and circumference as a standard weightlifting bar and differs only in that the shape of the bar is formed like a triangle with rounded edges. Theoretically, the shape of the bar will enhance gripping comfort and increase muscular endurance. We studied 32 moderately trained males who were free from upper-body injury or limitation. Each participant completed 4 visits to the lab as part of 2 separate investigations. The first investigation was a comparison of straight-arm hang times while grasping a standard Olympic bar or a Tri-Bar attached to the top of a power rack. The second investigation involved grasping a standard revolving cable handle or a Tri-Bar revolving handle attached to a weight equal to half the subject's body weight. In both investigations, time was used as a measure of isometric muscular endurance. Differences were determined using a dependent t-test, and a level of significance was set at p < 0.05. Mean hang times were significantly longer when the men hung from the Tri-Bar (107.6 seconds) versus the standard bar (95.4 seconds) (p = 0.015). Conversely, in the investigation using the revolving handles, the round bar produced longer grasping times (71.5 seconds) than the Tri-Bar (62.6 seconds) (p = 0.000). The results of this investigation indicate that a fixed and stable Tri-Bar may help to increase hang time, but a Tri-Bar free to rotate within the grasp may decrease grasping time in comparison to a standard round handle. With regard to exercises that require isometric grasping, the Tri-Bar may be an effective alternative to the standard bar for increasing isometric grasping endurance.

Using a combined protection motivation theory and health action process approach intervention to promote exercise during pregnancy.

PubMed

Gaston, Anca; Prapavessis, Harry

2014-04-01

Despite the benefits of exercise during pregnancy, many expectant mothers are inactive. This study examined whether augmenting a protection motivation theory (PMT) intervention with a Health Action Process Approach can enhance exercise behavior change among pregnant women. Sixty inactive pregnant women were randomly assigned to one of three treatment groups: PMT-only, PMT + action-planning, and PMT + action-and-coping-planning. Week-long objective (accelerometer) and subjective (self-report) exercise measures were collected at baseline, and at 1- and 4-weeks post-intervention. Repeated-measures ANOVAs demonstrated that while all participants reported increased exercise from baseline to 1-week post-intervention, participants in both planning groups were significantly more active (p < .001) than those in the PMT-only group by 4-weeks post-intervention (η (2) = .13 and .15 for accelerometer and self-report data, respectively). In conclusion, augmenting a PMT intervention with action or action-and-coping-planning can enhance exercise behavior change in pregnant women.

IMPROVEMENTS IN PSYCHOSOCIAL FUNCTIONING AND HEALTH-RELATED QUALITY OF LIFE FOLLOWING EXERCISE AUGMENTATION IN PATIENTS WITH TREATMENT RESPONSE BUT NONREMITTED MAJOR DEPRESSIVE DISORDER: RESULTS FROM THE TREAD STUDY.

PubMed

Greer, Tracy L; Trombello, Joseph M; Rethorst, Chad D; Carmody, Thomas J; Jha, Manish K; Liao, Allen; Grannemann, Bruce D; Chambliss, Heather O; Church, Timothy S; Trivedi, Madhukar H

2016-09-01

Functional impairments often remain despite symptomatic improvement with antidepressant treatment, supporting the need for novel treatment approaches. The present study examined the extent to which exercise augmentation improved several domains of psychosocial functioning and quality of life (QoL) among depressed participants. Data were collected from 122 partial responders to antidepressant medication. Participants were randomized to either high- (16 kcal/kg of weight/week [KKW]) or low-dose (4-KKW) exercise. Participants completed a combination of supervised and home-based exercise for 12 weeks. The Short-Form Health Survey, Work and Social Adjustment Scale, Social Adjustment Scale, Quality of Life Enjoyment and Satisfaction Questionnaire, and Satisfaction with Life Scale were collected at 6 and 12 weeks. Participants with data for at least one of the two follow-up time points (n = 106) were analyzed using a linear mixed model to assess change from baseline within groups and the difference between groups for each psychosocial outcome measure. All analyses controlled for covariates, including baseline depressive symptomatology. Participants experienced significant improvements in functioning across tested domains, and generally fell within a healthy range of functioning on all measures at Weeks 6 and 12. Although no differences were found between exercise groups, improvements were observed across a variety of psychosocial and QoL domains, even in the low-dose exercise group. These findings support exercise augmentation of antidepressant treatment as a viable intervention for treatment-resistant depression to improve function in addition to symptoms. © 2016 Wiley Periodicals, Inc.

Improvements in psychosocial functioning and health-related quality of life following exercise augmentation in patients with treatment response but non-remitted major depressive disorder: Results from the TREAD study

PubMed Central

Greer, Tracy L.; Trombello, Joseph M.; Rethorst, Chad D.; Carmody, Thomas J.; Jha, Manish K.; Liao, Allen; Grannemann, Bruce D.; Chambliss, Heather O.; Church, Timothy S.; Trivedi, Madhukar H.

2016-01-01

BACKGROUND Functional impairments often remain despite symptomatic improvement with antidepressant treatment, supporting the need for novel treatment approaches. The present study examined the extent to which exercise augmentation improved several domains of psychosocial functioning and quality of life among depressed participants. METHODS Data were collected from 122 partial responders to antidepressant medication. Participants were randomized to either high (16 kilocalories per kilogram of weight per week [KKW]) or low dose (4KKW) exercise. Participants completed a combination of supervised and home-based exercise for 12 weeks. The Short-Form Health Survey, Work and Social Adjustment Scale, Social Adjustment Scale, the Quality of Life Enjoyment and Satisfaction Questionnaire, and the Satisfaction with Life Scale were collected at 6 and 12 weeks. Participants with data for at least one of the two follow-up time points (n=106) were analyzed using a linear mixed model to assess change from baseline within groups and the difference between groups for each psychosocial outcome measure. All analyses controlled for covariates, including baseline depressive symptomatology. RESULTS Participants experienced significant improvements in functioning across tested domains, and generally fell within a healthy range of functioning on all measures at Weeks 6 and 12. While no differences were found between exercise groups, improvements were observed across a variety of psychosocial and quality-of-life domains, even in the low exercise dose group. CONCLUSIONS These findings support exercise augmentation of antidepressant treatment as a viable intervention for treatment-resistant depression to improve function in addition to symptoms. PMID:27164293

The effects of dietary fish oil on exercising skeletal muscle vascular and metabolic control in chronic heart failure rats.

PubMed

Holdsworth, Clark T; Copp, Steven W; Hirai, Daniel M; Ferguson, Scott K; Sims, Gabrielle E; Hageman, Karen S; Stebbins, Charles L; Poole, David C; Musch, Timothy I

2014-03-01

Impaired vasomotor control in chronic heart failure (CHF) is due partly to decrements in nitric oxide synthase (NOS) mediated vasodilation. Exercising muscle blood flow (BF) is augmented with polyunsaturated fatty acid (PUFA) supplementation via fish oil (FO) in healthy rats. We hypothesized that FO would augment exercising muscle BF in CHF rats via increased NO-bioavailability. Myocardial infarction (coronary artery ligation) induced CHF in Sprague-Dawley rats which were subsequently randomized to dietary FO (20% docosahexaenoic acid, 30% eicosapentaenoic acid, n = 15) or safflower oil (SO, 5%, n = 10) for 6-8 weeks. Mean arterial pressure (MAP), blood [lactate], and hindlimb muscles BF (radiolabeled microspheres) were determined at rest, during treadmill exercise (20 m·min(-1), 5% incline) and exercise + N(G)-nitro-l-arginine-methyl-ester (l-NAME) (a nonspecific NOS inhibitor). FO did not change left ventricular end-diastolic pressure (SO: 14 ± 2; FO: 11 ± 1 mm Hg, p > 0.05). During exercise, MAP (SO: 128 ± 3; FO: 132 ± 3 mm Hg) and blood [lactate] (SO: 3.8 ± 0.4; FO: 4.6 ± 0.5 mmol·L(-1)) were not different (p > 0.05). Exercising hindlimb muscle BF was lower in FO than SO (SO: 120 ± 11; FO: 93 ± 4 mL·min(-1)·100 g(-1), p < 0.05) but was not differentially affected by l-NAME. Specifically, 17 of 28 individual muscle BF's were lower (p < 0.05) in FO demonstrating that PUFA supplementation with FO in CHF rats does not augment muscle BF during exercise but may lower metabolic cost.

Blood flow dynamics in heart failure

NASA Technical Reports Server (NTRS)

Shoemaker, J. K.; Naylor, H. L.; Hogeman, C. S.; Sinoway, L. I.

1999-01-01

BACKGROUND: Exercise intolerance in heart failure (HF) may be due to inadequate vasodilation, augmented vasoconstriction, and/or altered muscle metabolic responses that lead to fatigue. METHODS AND RESULTS: Vascular and metabolic responses to rhythmic forearm exercise were tested in 9 HF patients and 9 control subjects (CTL) during 2 protocols designed to examine the effect of HF on the time course of oxygen delivery versus uptake (protocol 1) and on vasoconstriction during exercise with 50 mm Hg pressure about the forearm to evoke a metaboreflex (protocol 2). In protocol 1, venous lactate and H+ were greater at 4 minutes of exercise in HF versus CTL (P<0.05) despite similar blood flow and oxygen uptake responses. In protocol 2, mean arterial pressure increased similarly in each group during ischemic exercise. In CTL, forearm blood flow and vascular conductance were similar at the end of ischemic and ambient exercise. In HF, forearm blood flow and vascular conductance were reduced during ischemic exercise compared with the ambient trial. CONCLUSIONS: Intrinsic differences in skeletal muscle metabolism, not vasodilatory dynamics, must account for the augmented glycolytic metabolic responses to moderate-intensity exercise in class II and III HF. The inability to increase forearm vascular conductance during ischemic handgrip exercise, despite a normal pressor response, suggests that enhanced vasoconstriction of strenuously exercising skeletal muscle contributes to exertional fatigue in HF.

Understanding Patenting Decisions: A Classroom Exercise

ERIC Educational Resources Information Center

Bernard, John C.; Yiannaka, Amalia

2010-01-01

Although many students have some knowledge of patents, it can be difficult for them to understand the components of an innovator's decision-making process. Key issues, such as whether to patent or to use trade secrecy, how broad a scope to claim, and what to do in the event of patent infringement, can be difficult to grasp from a standard lecture.…

New Ratings of Humanities Journals Do More than Rank--They Rankle

ERIC Educational Resources Information Center

Howard, Jennifer

2008-01-01

This paper reports that a large-scale, multinational attempt in Europe to rank humanities journals has set off a revolt. In a protest letter, some journal editors have called it "a dangerous and misguided exercise." The project has also started a drumbeat of alarm in this country, as U.S.-based scholars begin to grasp the implications…

A Classroom Demonstration of How Individual Interpretations Shape Recollections of Past Events: It's Not Just a Game

ERIC Educational Resources Information Center

Walter, Mark I.; Walter, Jamie L.

2010-01-01

Courses in a wide variety of disciplines emphasize that what we think important, and are therefore likely to remember, is not the result of the objective situation but rather the result of our individual biases and interpretations. This article presents a classroom exercise that aids students in grasping the interpretive nature of historical…

Leucine-Enriched Essential Amino Acids Augment Mixed Protein Synthesis, But Not Collagen Protein Synthesis, in Rat Skeletal Muscle after Downhill Running

PubMed Central

Kato, Hiroyuki; Suzuki, Hiromi; Inoue, Yoshiko; Suzuki, Katsuya; Kobayashi, Hisamine

2016-01-01

Mixed and collagen protein synthesis is elevated for as many as 3 days following exercise. Immediately after exercise, enhanced amino acid availability increases synthesis of mixed muscle protein, but not muscle collagen protein. However, the potential for synergic effects of amino acid ingestion with exercise on both mixed and collagen protein synthesis remains unclear. We investigated muscle collagen protein synthesis in rats following post-exercise ingestion of leucine-enriched essential amino acids. We determined fractional protein synthesis rates (FSR) at different time points following exercise. Mixed protein and collagen protein FSRs in skeletal muscle were determined by measuring protein-bound enrichments of hydroxyproline and proline, and by measuring the intracellular enrichment of proline, using injections of flooding d3-proline doses. A leucine-enriched mixture of essential amino acids (or distilled water as a control) was administrated 30 min or 1 day post-exercise. The collagen protein synthesis in the vastus lateralis was elevated for 2 days after exercise. Although amino acid administration did not increase muscle collagen protein synthesis, it did lead to augmented mixed muscle protein synthesis 1 day following exercise. Thus, contrary to the regulation of mixed muscle protein synthesis, muscle collagen protein synthesis is not affected by amino acid availability after damage-inducing exercise. PMID:27367725

Making the Rate: Enzyme Dynamics

ERIC Educational Resources Information Center

Ragsdale, Frances R.

2004-01-01

An enzyme exercise to address the problem of students inability to visualize chemical reaction at the molecular level is described. This exercise is designed as a dry lab exercise but can be modified into a classroom activity then can be augmented by a wet lab procedure, thereby providing students with a practical exposure to enzyme function.

Acute changes in arterial stiffness following exercise in people with metabolic syndrome.

PubMed

Radhakrishnan, Jeyasundar; Swaminathan, Narasimman; Pereira, Natasha M; Henderson, Keiran; Brodie, David A

This study aims to examine the changes in arterial stiffness immediately following sub-maximal exercise in people with metabolic syndrome. Ninety-four adult participants (19-80 years) with metabolic syndrome gave written consent and were measured for arterial stiffness using a SphygmoCor (SCOR-PVx, Version 8.0, Atcor Medical Private Ltd, USA) immediately before and within 5-10min after an incremental shuttle walk test. The arterial stiffness measures used were pulse wave velocity (PWV), aortic pulse pressure (PP), augmentation pressure, augmentation index (AI), subendocardial viability ratio (SEVR) and ejection duration (ED). There was a significant increase (p<0.05) in most of the arterial stiffness variables following exercise. Exercise capacity had a strong inverse correlation with arterial stiffness and age (p<0.01). Age influences arterial stiffness. Exercise capacity is inversely related to arterial stiffness and age in people with metabolic syndrome. Exercise induced changes in arterial stiffness measured using pulse wave analysis is an important tool that provides further evidence in studying cardiovascular risk in metabolic syndrome. Copyright © 2016 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Possible applications of the LEAP motion controller for more interactive simulated experiments in augmented or virtual reality

NASA Astrophysics Data System (ADS)

Wozniak, Peter; Vauderwange, Oliver; Mandal, Avikarsha; Javahiraly, Nicolas; Curticapean, Dan

2016-09-01

Practical exercises are a crucial part of many curricula. Even simple exercises can improve the understanding of the underlying subject. Most experimental setups require special hardware. To carry out e. g. a lens experiments the students need access to an optical bench, various lenses, light sources, apertures and a screen. In our previous publication we demonstrated the use of augmented reality visualization techniques in order to let the students prepare with a simulated experimental setup. Within the context of our intended blended learning concept we want to utilize augmented or virtual reality techniques for stationary laboratory exercises. Unlike applications running on mobile devices, stationary setups can be extended more easily with additional interfaces and thus allow for more complex interactions and simulations in virtual reality (VR) and augmented reality (AR). The most significant difference is the possibility to allow interactions beyond touching a screen. The LEAP Motion controller is a small inexpensive device that allows for the tracking of the user's hands and fingers in three dimensions. It is conceivable to allow the user to interact with the simulation's virtual elements by the user's very hand position, movement and gesture. In this paper we evaluate possible applications of the LEAP Motion controller for simulated experiments in augmented and virtual reality. We pay particular attention to the devices strengths and weaknesses and want to point out useful and less useful application scenarios.

RoboGlove-A Grasp Assist Device for Earth and Space

NASA Technical Reports Server (NTRS)

Diftler, M. A.; Ihrke, C. A.; Bridgwater, L. B.; Rogers, J. M.; Davis, D. R.; Linn, D. M.; Laske, E. A.; Ensley, K. G.; Lee, J. H.

2015-01-01

The RoboGlove is an assistive device that can augment human strength, endurance or provide directed motion for use in rehabilitation. RoboGlove is a spinoff of the highly successful Robonaut 2 (R2) system developed as part of a partnership between General Motors and NASA. This extremely lightweight device employs an actuator system based on the R2 finger drive system to transfer part or the entire grasp load from human tendons to artificial ones contained in the glove. Steady state loads ranging from 15 to 20 lbs. and peaks approaching 50 lbs. are achievable. Work is underway to integrate the RoboGlove system with a space suit glove to add strength or reduce fatigue during spacewalks. Tactile sensing, miniaturized electronics, and on-board processing provide sufficient flexibility for applications in many industries. The following describes the design, mechanical/electrical integration, and control features of the glove in an assembly-line configuration and discusses work toward the space suit application.

Pulmonary Vascular Response Patterns During Exercise in Left Ventricular Systolic Dysfunction Predict Exercise Capacity and Outcomes

PubMed Central

Lewis, Gregory D.; Murphy, Ryan M.; Shah, Ravi V.; Pappagianopoulos, Paul P.; Malhotra, Rajeev; Bloch, Kenneth D.; Systrom, David M.; Semigran, Marc J.

2012-01-01

Background Elevated resting pulmonary arterial pressure (PAP) in patients with left ventricular systolic dysfunction (LVSD) purports a poor prognosis. However, PAP response patterns to exercise in LVSD and their relationship to functional capacity and outcomes have not been characterized. Methods and Results Sixty consecutive patients with LVSD (age 60±12 years, LV ejection fraction 0.31±0.07, mean±SD) and 19 controls underwent maximum incremental cardiopulmonary exercise testing with simultaneous hemodynamic monitoring. During low-level exercise (30 Watts), LVSD subjects compared to controls, had greater augmentation in mean PAPs (15±1 vs. 5±1 mmHg), transpulmonary gradients (5±1 vs. 1±1 mmHg), and effective PA elastance (0.05±0.02 vs. −0.03±0.01 mmHg/ml, p<0.0001 for all). A linear increment in PAP relative to work (0.28±0.12 mmHg/watt) was observed in 65% of LVSD patients, which exceeded that observed in controls (0.07±0.02 mmHg/watt, P<0.0001). Exercise capacity and survival was worse in patients with a PAP/watt slope above the median than in patients with a lower slope. In the remaining 35% of LVSD patients, exercise induced a steep initial increment in PAP (0.41±0.16 mmHg/watt) followed by a plateau. The plateau pattern, compared to a linear pattern, was associated with reduced peak VO2 (10.6±2.6 vs. 13.1±4.0 ml/kg/min, P=0.005), lower right ventricular stroke work index augmentation with exercise (5.7±3.8 vs. 9.7±5.0 g/m2, P=0.002), and increased mortality (HR 8.1, 95% CI 2.7-23.8, P<0.001). Conclusions A steep increment in PAP during exercise and failure to augment PAP throughout exercise are associated with decreased exercise capacity and survival in patients with LVSD, and may therefore represent therapeutic targets. Clinical Trial Information URL: http://www.clinicaltrials.gov. Unique Identifier: NCT00309790) PMID:21292991

[Engineering and expertise in sustainable development in hospitals].

PubMed

Barat, Pascal

2012-01-01

Sustainable development is nowadays a concept shared by most people even if it is sometimes hard to grasp. Combining good economic management, social progress and the protection of the environment is not always easy. It is however an essential exercise in order not to compromise the ability of future generations to meet their requirements. Tours University Hospital embarked on a sustainable development strategy in 2008.

Randomized Controlled Trial Comparing Orthosis Augmented by Either Stretching or Stretching and Strengthening for Stage II Tibialis Posterior Tendon Dysfunction.

PubMed

Houck, Jeff; Neville, Christopher; Tome, Josh; Flemister, Adolph

2015-09-01

The value of strengthening and stretching exercises combined with orthosis treatment in a home-based program has not been evaluated. The purpose of this study was to compare the effects of augmenting orthosis treatment with either stretching or a combination of stretching and strengthening in participants with stage II tibialis posterior tendon dysfunction (TPTD). Participants included 39 patients with stage II TPTD who were recruited from a medical center and then randomly assigned to a strengthening or stretching treatment group. Excluding 3 dropouts, there were 19 participants in the strengthening group and 17 in the stretching group. The stretching treatment consisted of a prefabricated orthosis used in conjunction with stretching exercises. The strengthening treatment consisted of a prefabricated orthosis used in conjunction with the stretching and strengthening exercises. The main outcome measures were self-report (ie, Foot Function Index and Short Musculoskeletal Function Assessment) and isometric deep posterior compartment strength. Two-way analysis of variance was used to test for differences between groups at 6 and 12 weeks after starting the exercise programs. Both groups significantly improved in pain and function over the 12-week trial period. The self-report measures showed minimal differences between the treatment groups. There were no differences in isometric deep posterior compartment strength. A moderate-intensity, home-based exercise program was minimally effective in augmenting orthosis wear alone in participants with stage II TPTD. Level I, prospective randomized study. © The Author(s) 2015.

Exercise is an effective treatment for positive valence symptoms in major depression.

PubMed

Toups, Marisa; Carmody, Thomas; Greer, Tracy; Rethorst, Chad; Grannemann, Bruce; Trivedi, Madhukar H

2017-02-01

Measurement of symptoms domains and their response to treatment in relative isolation from diagnosed mental disorders has gained new urgency, as reflected by the National Institute of Mental Health's introduction of the Research Domain Criteria (RDoC). The Snaith Hamilton Pleasure Scale (SHAPS) and the Motivation and Energy Inventory (MEI) are two scales measuring positive valence symptoms. We evaluated the effect of exercise on positive valence symptoms of Major Depressive Disorder (MDD). Subjects in the Treatment with Exercise Augmentation for Depression (TREAD) study completed self-reported SHAPS and MEI during 12 weeks of exercise augmentation for depression. We evaluated the effect of exercise on SHAPS and MEI scores, and whether the changes were related to overall MDD severity measured with the Quick Inventory of Depression Symptomatology (QIDS). SHAPS and MEI scores significantly improved with exercise. MEI score change had larger effect size and greater correlation with change in QIDS score. MEI also showed significant moderator and mediator effects of exercise in MDD. Generalizability to other treatments is limited. This study lacked other bio-behavioral markers that would enhance understanding of the relationship of RDoC and the measures used. Positive valence symptoms improve with exercise treatment for depression, and this change correlates well with overall outcome. Motivation and energy may be more clinically relevant to outcome of exercise treatment than anhedonia. Copyright © 2016. Published by Elsevier B.V.

Initial Work Toward a Robotically Assisted EVA Glove

NASA Technical Reports Server (NTRS)

Rogers, J.; Peters, B.; McBryan, E.; Laske, E.

2016-01-01

The Space Suit RoboGlove is a device designed to provide additional grasp strength or endurance for an EVA crew member since gloved hand performance is a fraction of what the unencumbered human hand can achieve. There have been past efforts to approach this problem by employing novel materials and construction techniques to the glove design, as well as integrating powered assistance devices. This application of the NASA/GM RoboGlove technology uses a unique approach to integrate the robotic actuators and sensors into a Phase VI EVA glove. This design provides grasp augmentation to the glove user while active, but can also function as a normal glove when disabled. Care was taken to avoid adding excessive bulk to the glove or affecting tactility by choosing low-profile sensors and extrinsically locating the actuators. Conduits are used to guide robotic tendons from linear actuators, across the wrist, and to the fingers. The second generation of the SSRG includes updated electronics, sensors, and actuators to improve performance. The following discusses the electromechanical design, softgoods integration, and control system of the SSRG. It also presents test results from the first integration of a powered mobility element onto a space suit, the NASA Mark III. Early results show that sensor integration did not impact tactile feedback in the glove and the actuators show potential for reduction in grasp fatigue over time.

Creatine ingestion augments dietary carbohydrate mediated muscle glycogen supercompensation during the initial 24 h of recovery following prolonged exhaustive exercise in humans.

PubMed

Roberts, Paul A; Fox, John; Peirce, Nicholas; Jones, Simon W; Casey, Anna; Greenhaff, Paul L

2016-08-01

Muscle glycogen availability can limit endurance exercise performance. We previously demonstrated 5 days of creatine (Cr) and carbohydrate (CHO) ingestion augmented post-exercise muscle glycogen storage compared to CHO feeding alone in healthy volunteers. Here, we aimed to characterise the time-course of this Cr-induced response under more stringent and controlled experimental conditions and identify potential mechanisms underpinning this phenomenon. Fourteen healthy, male volunteers cycled to exhaustion at 70 % VO2peak. Muscle biopsies were obtained at rest immediately post-exercise and after 1, 3 and 6 days of recovery, during which Cr or placebo supplements (20 g day(-1)) were ingested along with a prescribed high CHO diet (37.5 kcal kg body mass(-1) day(-1), >80 % calories CHO). Oral-glucose tolerance tests (oral-GTT) were performed pre-exercise and after 1, 3 and 6 days of Cr and placebo supplementation. Exercise depleted muscle glycogen content to the same extent in both treatment groups. Creatine supplementation increased muscle total-Cr, free-Cr and phosphocreatine (PCr) content above placebo following 1, 3 and 6 days of supplementation (all P < 0.05). Creatine supplementation also increased muscle glycogen content noticeably above placebo after 1 day of supplementation (P < 0.05), which was sustained thereafter. This study confirmed dietary Cr augments post-exercise muscle glycogen super-compensation, and demonstrates this occurred during the initial 24 h of post-exercise recovery (when muscle total-Cr had increased by <10 %). This marked response ensued without apparent treatment differences in muscle insulin sensitivity (oral-GTT, muscle GLUT4 mRNA), osmotic stress (muscle c-fos and HSP72 mRNA) or muscle cell volume (muscle water content) responses, such that another mechanism must be causative.

Adenosine receptor antagonist and augmented vasodilation during hypoxic exercise

PubMed Central

Madery, Brandon D.; Pike, Tasha L.; Eisenach, John H.; Dietz, Niki M.; Joyner, Michael J.; Wilkins, Brad W.

2009-01-01

We tested the hypothesis that adenosine contributes to augmented skeletal muscle vasodilation during hypoxic exercise. In separate protocols, subjects performed incremental rhythmic forearm exercise (10% and 20% of maximum) during normoxia and normocapnic hypoxia (80% arterial O2 saturation). In protocol 1 (n = 8), subjects received an intra-arterial administration of saline (control) and aminophylline (adenosine receptor antagonist). In protocol 2 (n = 10), subjects received intra-arterial phentolamine (α-adrenoceptor antagonist) and combined phentolamine and aminophylline administration. Forearm vascular conductance (FVC; in ml·min−1·100 mmHg−1) was calculated from forearm blood flow (in ml/min) and blood pressure (in mmHg). In protocol 1, the change in FVC (ΔFVC; change from normoxic baseline) during hypoxic exercise with saline was 172 ± 29 and 314 ± 34 ml·min−1·100 mmHg−1 (10% and 20%, respectively). Aminophylline administration did not affect ΔFVC during hypoxic exercise at 10% (190 ± 29 ml·min−1·100 mmHg−1, P = 0.4) or 20% (287 ± 48 ml·min−1·100 mmHg−1, P = 0.3). In protocol 2, ΔFVC due to hypoxic exercise with phentolamine infusion was 313 ± 30 and 453 ± 41 ml·min−1·100 mmHg−1 (10% and 20% respectively). ΔFVC was similar at 10% (352 ± 39 ml·min−1·100 mmHg−1, P = 0.8) and 20% (528 ± 45 ml·min−1·100 mmHg−1, P = 0.2) hypoxic exercise with combined phentolamine and aminophylline. In contrast, ΔFVC to exogenous adenosine was reduced by aminophylline administration in both protocols (P < 0.05 for both). These observations suggest that adenosine receptor activation is not obligatory for the augmented hyperemia during hypoxic exercise in humans. PMID:19661449

Exercise as an augmentation treatment for nonremitted major depressive disorder: a randomized, parallel dose comparison.

PubMed

Trivedi, Madhukar H; Greer, Tracy L; Church, Timothy S; Carmody, Thomas J; Grannemann, Bruce D; Galper, Daniel I; Dunn, Andrea L; Earnest, Conrad P; Sunderajan, Prabha; Henley, Steven S; Blair, Steven N

2011-05-01

Most patients with major depressive disorder (MDD) require second-step treatments to achieve remission. The Treatment with Exercise Augmentation for Depression (TREAD) study was designed to test the efficacy of aerobic exercise as an augmentation treatment for MDD patients who had not remitted with antidepressant treatment. Eligible participants in this randomized controlled trial were sedentary individuals (men and women aged 18-70 years) diagnosed with DSM-IV nonpsychotic MDD who had not remitted with selective serotonin reuptake inhibitor (SSRI) treatment. Participants were recruited through physician referrals and advertisements. A total of 126 participants were randomized to augmentation treatment with either 16 kcal per kg per week (KKW) or 4 KKW of exercise expenditure for 12 weeks while SSRI treatment was held constant. Supervised sessions were conducted at The Cooper Institute, Dallas, Texas, with additional home-based sessions as needed to fulfill the weekly exercise prescription. The primary outcome was remission (as determined by a score ≤ 12 on the Inventory of Depressive Symptomatology, Clinician-Rated). The study took place between August 2003 and August 2007. There were significant improvements over time for both groups combined (F₁,₁₂₁ = 39.9, P < .0001), without differential group effect (group effect: F₁,₁₃₄ = 3.2, P = .07; group-by-time effect: F₁,₁₁₉ = 3.8, P = .06). Adjusted remission rates at week 12 were 28.3% versus 15.5% for the 16-KKW and 4-KKW groups, respectively, leading to a number needed to treat (NNT) of 7.8 for 16 KKW versus 4 KKW. Men, regardless of family history of mental illness, and women without a family history of mental illness had higher remission rates by week 12 with higher-dose (women, 39.0%; men, 85.4%) than with lower-dose exercise (women, 5.6%; men, 0.1%) (women: t₉₅ = 2.1, P = .04; men: t₈₈ = 5.4, P < .0001) (NNT: women, 3.0; men, 1.2). There was a trend for higher remission rates in the higher-dose exercise group (P < .06), with a clinically meaningful NNT of 7.8 in favor of the high exercise dose. Significant differences between groups were found when the moderating effects of gender and family history of mental illness were taken into account and suggest that higher-dose exercise may be better for all men and for women without a family history of mental illness. clinicaltrials.gov Identifier: NCT00076258. © Copyright 2011 Physicians Postgraduate Press, Inc.

Acute exercise enhances the consolidation of fear extinction memory and reduces conditioned fear relapse in a sex-dependent manner.

PubMed

Bouchet, Courtney A; Lloyd, Brian A; Loetz, Esteban C; Farmer, Caroline E; Ostrovskyy, Mykola; Haddad, Natalie; Foright, Rebecca M; Greenwood, Benjamin N

2017-08-01

Fear extinction-based exposure therapy is the most common behavioral therapy for anxiety and trauma-related disorders, but fear extinction memories are labile and fear tends to return even after successful extinction. The relapse of fear contributes to the poor long-term efficacy of exposure therapy. A single session of voluntary exercise can enhance the acquisition and consolidation of fear extinction in male rats, but the effects of exercise on relapse of fear after extinction are not well understood. Here, we characterized the effects of 2 h of voluntary exercise during the consolidation phase of contextual or auditory fear extinction learning on long-term fear extinction memory and renewal in adult, male and female, Long-Evans rats. Results indicate that exercise enhances consolidation of fear extinction memory and reduces fear relapse after extinction in a sex-dependent manner. These data suggest that brief bouts of exercise could be used as an augmentation strategy for exposure therapy, even in previously sedentary subjects. Fear memories of discrete cues, rather than of contextual ones, may be most susceptible to exercise-augmented extinction, especially in males. Additionally, exercise seems to have the biggest impact on fear relapse phenomena, even if fear extinction memories themselves are only minimally enhanced. © 2017 Bouchet et al.; Published by Cold Spring Harbor Laboratory Press.

Effects of combined aerobic and resistance exercise on central arterial stiffness and gait velocity in patients with chronic poststroke hemiparesis.

PubMed

Lee, Yong Hee; Park, Soo Hyun; Yoon, Eun Sun; Lee, Chong-Do; Wee, Sang Ouk; Fernhall, Bo; Jae, Sae Young

2015-09-01

The effects of combined aerobic and resistance exercise training on central arterial stiffness and gait velocity in patients with chronic poststroke hemiparesis were investigated. Twenty-six patients with chronic poststroke hemiparesis were randomly assigned to either the combined aerobic and resistance exercise group (n = 14) or the control group (n = 12). The exercise intervention group received a combined aerobic and resistance exercise training (1 hr/day, three times/week for 16 wks), whereas the control group received usual care. Central arterial stiffness was determined by pulse wave velocity and augmentation index. Gait velocity was assessed using the 6-min walk test, 10-m walk test, and the Timed Up-and-Go test. Patients in the exercise intervention group had greater improvement of mean pulse wave velocity (P < 0.001), augmentation index (P = 0.048), and gait velocity (6-min walk test, P < 0.001; 10-m walk test, P < 0.001) than did patients in the control group. Patients in the exercise intervention group also had greater improvements in physical fitness component (grip strength, P < 0.001; muscular strength of upper and lower limbs, P < 0.027; flexibility, P < 0.001) when compared with control patients. The combined aerobic and resistance exercise program significantly reduced central arterial stiffness and increased gait velocity in patients with chronic poststroke hemiparesis.

Effects of performing morning versus afternoon exercise on glycemic control and hypoglycemia frequency in type 1 diabetes patients on sensor-augmented insulin pump therapy.

PubMed

Gomez, Ana Maria; Gomez, Claudia; Aschner, Pablo; Veloza, Angelica; Muñoz, Oscar; Rubio, Claudia; Vallejo, Santiago

2015-05-01

Although physical exercise (PE) is recommended for individuals with type 1 diabetes (DM1), participation in exercise is challenging because it increases the risk of severe hypoglycemia and the available therapeutic options to prevent it frequently result in hyperglycemia. There is no clear recommendation about the best timing for exercise. The aim of this study was to compare the risk of hypoglycemia after morning or afternoon exercise sessions up to 36 hours postworkout. This randomized crossover study enrolled subjects with DM1, older than 18 years of age, on sensor-augmented insulin pump (SAP) therapy. Participants underwent 2 moderate-intensity exercise sessions; 1 in the morning and 1 in the afternoon, separated by a 7 to 14 day wash-out period. Continuous glucose monitoring (CGM) data were collected 24 hours before, during and 36 hours after each session. Thirty-five subjects (mean age 30.31 ± 12.66 years) participated in the study. The rate of hypoglycemia was significantly lower following morning versus afternoon exercise sessions (5.6 vs 10.7 events per patient, incidence rate ratio, 0.52; 95% CI, 0.43-0.63; P < .0001). Most hypoglycemic events occurred 15-24 hours after the session. On days following morning exercise sessions, there were 20% more CGM readings in near-euglycemic range (70-200 mg/dL) than on days prior to morning exercise (P = .003). Morning exercise confers a lower risk of late-onset hypoglycemia than afternoon exercise and improves metabolic control on the subsequent day. © 2015 Diabetes Technology Society.

Randomized trial of a dual-hormone artificial pancreas with dosing adjustment during exercise compared with no adjustment and sensor-augmented pump therapy.

PubMed

Jacobs, P G; El Youssef, J; Reddy, R; Resalat, N; Branigan, D; Condon, J; Preiser, N; Ramsey, K; Jones, M; Edwards, C; Kuehl, K; Leitschuh, J; Rajhbeharrysingh, U; Castle, J R

2016-11-01

To test whether adjusting insulin and glucagon in response to exercise within a dual-hormone artificial pancreas (AP) reduces exercise-related hypoglycaemia. In random order, 21 adults with type 1 diabetes (T1D) underwent three 22-hour experimental sessions: AP with exercise dosing adjustment (APX); AP with no exercise dosing adjustment (APN); and sensor-augmented pump (SAP) therapy. After an overnight stay and 2 hours after breakfast, participants exercised for 45 minutes at 60% of their maximum heart rate, with no snack given before exercise. During APX, insulin was decreased and glucagon was increased at exercise onset, while during SAP therapy, subjects could adjust dosing before exercise. The two primary outcomes were percentage of time spent in hypoglycaemia (<3.9 mmol/L) and percentage of time spent in euglycaemia (3.9-10 mmol/L) from the start of exercise to the end of the study. The mean (95% confidence interval) times spent in hypoglycaemia (<3.9 mmol/L) after the start of exercise were 0.3% (-0.1, 0.7) for APX, 3.1% (0.8, 5.3) for APN, and 0.8% (0.1, 1.4) for SAP therapy. There was an absolute difference of 2.8% less time spent in hypoglycaemia for APX versus APN (p = .001) and 0.5% less time spent in hypoglycaemia for APX versus SAP therapy (p = .16). Mean time spent in euglycaemia was similar across the different sessions. Adjusting insulin and glucagon delivery at exercise onset within a dual-hormone AP significantly reduces hypoglycaemia compared with no adjustment and performs similarly to SAP therapy when insulin is adjusted before exercise. © 2016 John Wiley & Sons Ltd.

Hemodynamic and arterial stiffness differences between African-Americans and Caucasians after maximal exercise.

PubMed

Yan, Huimin; Ranadive, Sushant M; Heffernan, Kevin S; Lane, Abbi D; Kappus, Rebecca M; Cook, Marc D; Wu, Pei-Tzu; Sun, Peng; Harvey, Idethia S; Woods, Jeffrey A; Wilund, Kenneth R; Fernhall, Bo

2014-01-01

African-American (AA) men have higher arterial stiffness and augmentation index (AIx) than Caucasian-American (CA) men. Women have greater age-associated increases in arterial stiffness and AIx than men. This study examined racial and sex differences in arterial stiffness and central hemodynamics at rest and after an acute bout of maximal exercise in young healthy individuals. One hundred young, healthy individuals (28 AA men, 24 AA women, 25 CA men, and 23 CA women) underwent measurements of aortic blood pressure (BP) and arterial stiffness at rest and 15 and 30 min after an acute bout of graded maximal aerobic exercise. Aortic BP and AIx were derived from radial artery applanation tonometry. Aortic stiffness (carotid-femoral) was measured via pulse wave velocity. Aortic stiffness was increased in AA subjects but not in CA subjects (P < 0.05) after an acute bout of maximal cycling exercise, after controlling for body mass index. Aortic BP decreased after exercise in CA subjects but not in AA subjects (P < 0.05). Women exhibited greater reductions in AIx after maximal aerobic exercise compared with men (P < 0.05). In conclusion, race and sex impact vascular and central hemodynamic responses to exercise. Young AA and CA subjects exhibited differential responses in central stiffness and central BP after acute maximal exercise. Premenopausal women had greater augmented pressure at rest and after maximal aerobic exercise than men. Future research is needed to examine the potential mechanisms.

Hemodynamic and arterial stiffness differences between African-Americans and Caucasians after maximal exercise

PubMed Central

Ranadive, Sushant M.; Heffernan, Kevin S.; Lane, Abbi D.; Kappus, Rebecca M.; Cook, Marc D.; Wu, Pei-Tzu; Sun, Peng; Harvey, Idethia S.; Woods, Jeffrey A.; Wilund, Kenneth R.; Fernhall, Bo

2013-01-01

African-American (AA) men have higher arterial stiffness and augmentation index (AIx) than Caucasian-American (CA) men. Women have greater age-associated increases in arterial stiffness and AIx than men. This study examined racial and sex differences in arterial stiffness and central hemodynamics at rest and after an acute bout of maximal exercise in young healthy individuals. One hundred young, healthy individuals (28 AA men, 24 AA women, 25 CA men, and 23 CA women) underwent measurements of aortic blood pressure (BP) and arterial stiffness at rest and 15 and 30 min after an acute bout of graded maximal aerobic exercise. Aortic BP and AIx were derived from radial artery applanation tonometry. Aortic stiffness (carotid-femoral) was measured via pulse wave velocity. Aortic stiffness was increased in AA subjects but not in CA subjects (P < 0.05) after an acute bout of maximal cycling exercise, after controlling for body mass index. Aortic BP decreased after exercise in CA subjects but not in AA subjects (P < 0.05). Women exhibited greater reductions in AIx after maximal aerobic exercise compared with men (P < 0.05). In conclusion, race and sex impact vascular and central hemodynamic responses to exercise. Young AA and CA subjects exhibited differential responses in central stiffness and central BP after acute maximal exercise. Premenopausal women had greater augmented pressure at rest and after maximal aerobic exercise than men. Future research is needed to examine the potential mechanisms. PMID:24186094

Inflammatory cytokine response to exercise in alpha-1-antitrypsin deficient COPD patients ‘on’ or ‘off’ augmentation therapy

PubMed Central

2014-01-01

Background There is still limited information on systemic inflammation in alpha-1-antitrypsin-deficient (AATD) COPD patients and what effect alpha-1-antitrypsin augmentation therapy and/or exercise might have on circulating inflammatory cytokines. We hypothesized that AATD COPD patients on augmentation therapy (AATD + AUG) would have lower circulating and skeletal muscle inflammatory cytokines compared to AATD COPD patients not receiving augmentation therapy (AATD-AUG) and/or the typical non-AATD (COPD) patient. We also hypothesized that cytokine response to exercise would be lower in AATD + AUG compared to AATD-AUG or COPD subjects. Methods Arterial and femoral venous concentration and skeletal muscle expression of TNFα, IL-6, IL-1β and CRP were measured at rest, during and up to 4-hours after 50% maximal 1-hour knee extensor exercise in all COPD patient groups, including 2 additional groups (i.e. AATD with normal lung function, and healthy age-/activity-matched controls). Results Circulating CRP was higher in AATD + AUG (4.7 ± 1.6 mg/dL) and AATD-AUG (3.3 ± 1.2 mg/dL) compared to healthy controls (1.5 ± 0.3 mg/dL, p < 0.05), but lower in AATD compared to non-AATD-COPD patients (6.1 ± 2.6 mg/dL, p < 0.05). TNFα, IL-6 and IL-1β were significantly increased by 1.7-, 1.7-, and 4.7-fold, respectively, in non-AATD COPD compared to AATD COPD (p < 0.05), and 1.3-, 1.7-, and 2.2-fold, respectively, compared to healthy subjects (p < 0.05). Skeletal muscle TNFα was on average 3–4 fold greater in AATD-AUG compared to the other groups (p < 0.05). Exercise showed no effect on these cytokines in any of our patient groups. Conclusion These data show that AATD COPD patients do not experience the same chronic systemic inflammation and exhibit reduced inflammation compared to non-AATD COPD patients. Augmentation therapy may help to improve muscle efflux of TNFα and reduce muscle TNFα concentration, but showed no effect on IL-6, IL-1β or CRP. PMID:24975928

Context-Aware Based Efficient Training System Using Augmented Reality and Gravity Sensor for Healthcare Services

NASA Astrophysics Data System (ADS)

Kim, Seoksoo; Jung, Sungmo; Song, Jae-Gu; Kang, Byong-Ho

As augmented reality and a gravity sensor is of growing interest, siginificant developement is being made on related technology, which allows application of the technology in a variety of areas with greater expectations. In applying Context-aware to augmented reality, it can make useful programs. A traning system suggested in this study helps a user to understand an effcienct training method using augmented reality and make sure if his exercise is being done propery based on the data collected by a gravity sensor. Therefore, this research aims to suggest an efficient training environment that can enhance previous training methods by applying augmented reality and a gravity sensor.

Plasma aldosterone and sweat sodium concentrations after exercise and heat acclimation

NASA Technical Reports Server (NTRS)

Kirby, C. R.; Convertino, V. A.

1986-01-01

The relationship between plasma aldosterone levels and sweat sodium excretion after chronic exercise and heat acclimation was investigated, using subjects exercised, at 40 C and 45 percent humidity, for 2 h/day on ten consecutive days at 45 percent of their maximal oxygen uptake. The data indicate that, following heat acclimation, plasma aldosterone concentrations decrease, and that the eccrine gland responsiveness to aldosterone, as represented by sweat sodium reabsorption, may be augmented through exercise and heat acclimation.

Trunk muscle activation during dynamic weight-training exercises and isometric instability activities.

PubMed

Hamlyn, Nicolle; Behm, David G; Young, Warren B

2007-11-01

The purpose of this study was to examine the extent of activation in various trunk muscles during dynamic weight-training and isometric instability exercises. Sixteen subjects performed squats and deadlifts with 80% 1 repetition maximum (1RM), as well as with body weight as resistance and 2 unstable calisthenic-type exercises (superman and sidebridge). Electromyographic (EMG) activity was measured from the lower abdominals (LA), external obliques (EO), upper lumbar erector spinae (ULES), and lumbar-sacral erector spinae (LSES) muscle groups. Results indicated that the LSES EMG activity during the 80% 1RM squat significantly exceeded 80% 1RM deadlift LSES EMG activity by 34.5%. The LSES EMG activity of the 80% 1RM squat also exceeded the body weight squat, deadlift, superman, and sidebridge by 56, 56.6, 65.5, and 53.1%, respectively. The 80% 1RM deadlift ULES EMG activity significantly exceeded the 80% 1RM squat exercise by 12.9%. In addition, the 80% 1RM deadlift ULES EMG activity also exceeded the body weight squat, deadlift, superman, and sidebridge exercises by 66.7, 65.5, 69.3, and 68.6%, respectively. There were no significant changes in EO or LA activity. Therefore, the augmented activity of the LSES and ULES during 80% 1RM squat and deadlift resistance exercises exceeded the activation levels achieved with the same exercises performed with body weight and selected instability exercises. Individuals performing upright, resisted, dynamic exercises can achieve high trunk muscle activation and thus may not need to add instability device exercises to augment core stability training.

Neurobiological mechanisms of exercise and psychotherapy in depression: The SPeED study-Rationale, design, and methodological issues.

PubMed

Heinzel, Stephan; Rapp, Michael A; Fydrich, Thomas; Ströhle, Andreas; Terán, Christina; Kallies, Gunnar; Schwefel, Melanie; Heissel, Andreas

2018-02-01

Even though cognitive behavioral therapy has become a relatively effective treatment for major depressive disorder and cognitive behavioral therapy-related changes of dysfunctional neural activations were shown in recent studies, remission rates still remain at an insufficient level. Therefore, the implementation of effective augmentation strategies is needed. In recent meta-analyses, exercise therapy (especially endurance exercise) was reported to be an effective intervention in major depressive disorder. Despite these findings, underlying mechanisms of the antidepressant effect of exercise especially in combination with cognitive behavioral therapy have rarely been studied to date and an investigation of its neural underpinnings is lacking. A better understanding of the psychological and neural mechanisms of exercise and cognitive behavioral therapy would be important for developing optimal treatment strategies in depression. The SPeED study (Sport/Exercise Therapy and Psychotherapy-evaluating treatment Effects in Depressive patients) is a randomized controlled trial to investigate underlying physiological, neurobiological, and psychological mechanisms of the augmentation of cognitive behavioral therapy with endurance exercise. It is investigated if a preceding endurance exercise program will enhance the effect of a subsequent cognitive behavioral therapy. This study will include 105 patients diagnosed with a mild or moderate depressive episode according to the Diagnostic and Statistical Manual of Mental Disorders (4th ed.). The participants are randomized into one of three groups: a high-intensive or a low-intensive endurance exercise group or a waiting list control group. After the exercise program/waiting period, all patients receive an outpatient cognitive behavioral therapy treatment according to a standardized therapy manual. At four measurement points, major depressive disorder symptoms (Beck Depression Inventory, Hamilton Rating Scale for Depression), (neuro)biological measures (neural activations during working memory, monetary incentive delay task, and emotion regulation, as well as cortisol levels and brain-derived neurotrophic factor), neuropsychological test performance, and questionnaires (psychological needs, self-efficacy, and quality of life) are assessed. In this article, we report the design of the SPeED study and refer to important methodological issues such as including both high- and low-intensity endurance exercise groups to allow the investigation of dose-response effects and physiological components of the therapy effects. The main aims of this research project are to study effects of endurance exercise and cognitive behavioral therapy on depressive symptoms and to investigate underlying physiological and neurobiological mechanisms of these effects. Results may provide important implications for the development of effective treatment strategies in major depressive disorder, specifically concerning the augmentation of cognitive behavioral therapy by endurance exercise.

An effective 3-fingered augmenting exoskeleton for the human hand.

PubMed

Gearhart, C J; Varone, B; Stella, M H; BuSha, B F

2016-08-01

Every year, thousands of Americans suffer from pathological and traumatic events that result in loss of dexterity and strength of the hand. Although many supportive devices have been designed to restore functional hand movement, most are very complex and expensive. The goal of this project was to design and implement a cost-effective, electrically powered exoskeleton for the human hand that could improve grasping strength. A 3-D printed thermoplastic exoskeleton that allowed independent and enhanced movement of the index, middle and ring fingers was constructed. In addition, a 3-D printed structure was designed to house three linear actuators, an Arduino-based control system, and a power supply. A single force sensing resistor was located on the lower inner-surface of the index fingertip which was used to proportionally activate the three motors, one motor per finger, as a function of finger force applied to the sensor. The device was tested on 4 normal human subjects. Results showed that the activation of the motor control system significantly reduced the muscle effort needed to maintain a sub-maximal grasp effort.

The role of sensory augmentation for people with vestibular deficits: Real-time balance aid and/or rehabilitation device?

PubMed

Sienko, K H; Whitney, S L; Carender, W J; Wall, C

2017-01-01

This narrative review highlights findings from the sensory augmentation field for people with vestibular deficits and addresses the outstanding questions that are critical to the translation of this technology into clinical and/or personal use. Prior research has demonstrated that the real-time use of visual, vibrotactile, auditory, and multimodal sensory augmentation technologies can improve balance during static and dynamic stance tasks within a laboratory setting. However, its application in improving gait requires additional investigation, as does its efficacy as a rehabilitation device for people with vestibular deficits. In some locomotor studies involving sensory augmentation, gait velocity decreased and secondary task performance worsened, and subjects negatively altered their segmental control strategies when cues were provided following short training sessions. A further question is whether the retention and/or carry-over effects of training with a sensory augmentation technology exceed the retention and/or carry-over effects of training alone, thereby supporting its use as a rehabilitation device. Preliminary results suggest that there are short-term improvements in balance performance following a small number of training sessions with a sensory augmentation device. Long-term clinical and home-based controlled training studies are needed. It is hypothesized that sensory augmentation provides people with vestibular deficits with additional sensory input to promote central compensation during a specific exercise/activity; however, research is needed to substantiate this theory. Major obstacles standing in the way of its use for these critical applications include determining exercise/activity specific feedback parameters and dosage strategies. This paper summarizes the reported findings that support sensory augmentation as a balance aid and rehabilitation device, but does not critically examine efficacy or the quality of the research methods used in the reviewed studies.

Treadmill training as an augmentation treatment for Alzheimer's disease: a pilot randomized controlled study.

PubMed

Arcoverde, Cynthia; Deslandes, Andrea; Moraes, Helena; Almeida, Cloyra; Araujo, Narahyana Bom de; Vasques, Paulo Eduardo; Silveira, Heitor; Laks, Jerson

2014-03-01

To assess the effect of aerobic exercise on the cognition and functional capacity in Alzheimer's disease (AD) patients. Elderly (n=20) with mild dementia (NINCDS-ADRDA/CDR1) were randomly assigned to an exercise group (EG) on a treadmill (30 minutes, twice a week and moderate intensity of 60% VO₂max) and control group (GC) 10 patients. The primary outcome measure was the cognitive function using Cambridge Cognitive Examination (CAMCOG). Specifics instruments were also applied to evaluate executive function, memory, attention and concentration, cognitive flexibility, inhibitory control and functional capacity. After 16 weeks, the EG showed improvement in cognition CAMCOG whereas the CG declined. Compared to the CG, the EG presented significant improvement on the functional capacity. The analysis of the effect size has shown a favorable response to the physical exercise in all dependent variables. Walking on treadmill may be recommended as an augmentation treatment for patients with AD.

Mean diffusivity as a potential diffusion tensor biomarker of motor rehabilitation after electrical stimulation incorporating task specific exercise in stroke: a pilot study.

PubMed

Boespflug, Erin L; Storrs, Judd M; Allendorfer, Jane B; Lamy, Martine; Eliassen, James C; Page, Stephen

2014-09-01

Changes in diffusion tensor imaging (DTI) values co-occur with neurological and functional changes after stroke. However, quantitative DTI metrics have not been examined in response to participation in targeted rehabilitative interventions in chronic stroke. The primary purpose of this pilot study was to examine whether changes in DTI metrics co-occur with paretic arm movement changes among chronic stroke patients participating in a regimen of electrical stimulation targeting the paretic arm. Three subjects exhibiting stable arm hemiparesis were administered 30-minute (n = 1) or 120-minute (n = 2) therapy sessions emphasizing paretic arm use during valued, functional tasks and incorporating an electrical stimulation device. These sessions occurred every weekday for 8 weeks. A fourth subject served as a treatment control, participating in a 30-minute home exercise regimen without electrical stimulation every weekday for 8 weeks. DTI and behavioral outcome measures were acquired at baseline and after intervention. DTI data were analyzed using a region of interest (ROI) approach, with ROIs chosen based on tract involvement in sensorimotor function or as control regions. Behavioral outcome measures were the Fugl-Meyer Scale (FM) and the Action Research Arm Test (ARAT). The treatment control subject exhibited gains in pinch and grasp, as shown by a 5-point increase on the ARAT. The subject who participated in 30-minute therapy sessions exhibited no behavioral gains. Subjects participating in 120-minute therapy sessions displayed consistent impairment reductions and distal movement changes. DTI changes were largest in subjects two and three, with mean diffusivity (MD) decreases in the middle cerebellar peduncle and posterior limb of the internal capsule following treatment. No changes in fractional anisotropy (FA) were observed for sensorimotor tracts. Our preliminary results suggest that active rehabilitative therapies augmented by electrical stimulation may induce positive behavioral changes which are underscored by DTI changes indicative of increased white matter tract integrity in regions specific to sensory-motor function.

Augmented baroreflex heart rate gain after moderate-intensity, dynamic exercise

NASA Technical Reports Server (NTRS)

Halliwill, J. R.; Taylor, J. A.; Hartwig, T. D.; Eckberg, D. L.

1996-01-01

The occurrence of a sustained vasodilation and hypotension after acute, dynamic exercise suggests that exercise may alter arterial baroreflex mechanisms. Therefore, we assessed systemic hemodynamics, baroreflex regulation of heart rate, and cardiac vagal tone after 60 min of cycling at 60% peak oxygen consumption in 12 healthy, untrained men and women (ages 21-28 yr). We derived sigmoidal carotid-cardiac baroreflex relations by measurement of R-R interval changes induced by ramped, stepwise, R-wave-triggered changes in external neck pressure from 40 to -65 mmHg. We estimated tonic cardiac vagal control with power spectral analysis of R-R interval variability in the respiratory frequency band (0.2-0.3 Hz) during frequency- and tidal volume-controlled breathing. Both mean arterial pressure and total peripheral resistance were reduced postexercise [pressure: from 86 +/- 2 (mean +/- SE) to 81 +/- 2 mmHg; resistance: from 23 +/- 2 to 16 +/- 1 units; both P < 0.05]. Cardiac output was increased postexercise (from 3.9 +/- 0.3 to 5.5 +/- 0.5 l/min, P < 0.05). Both slope and range of the carotid-cardiac baroreflex relation were increased postexercise (slope: from 4.7 +/- 0.7 to 6.1 +/- 0.9 ms/mmHg; range: from 186 +/- 23 to 238 +/- 30 ms, P < 0.05). Respiratory R-R interval variability (cardiac vagal tone) was not changed at any time after exercise, whereas heart rate and plasma norepinephrine levels were elevated. Thus moderate-intensity, dynamic exercise increases heart rate and cardiac output, reduces peripheral vascular resistance, and augments baroreflex responsiveness. Our data suggest that augmented baroreflex heart rate gain restrains rather than contributes to postexercise hypotension, which appears to be mediated predominately by vasodilation.

Effects of Static Stretching Exercise on Lumbar Flexibility and Central Arterial Stiffness.

PubMed

Logan, Jeongok G; Kim, Suk-Sun; Lee, Mijung; Byon, Ha Do; Yeo, SeonAe

Previous studies have demonstrated that arterial stiffness is associated with lumbar flexibility (LF). Stretching exercise targeted to improve LF may have a beneficial effect on reducing arterial stiffness. We examined the effects of a single bout of a structured, static stretching exercise on arterial stiffness, LF, peripheral and central blood pressure (BP), and heart rate (HR) and tested the association between LF and central arterial stiffness. The study had a pretest-posttest design without a control group. Thirty healthy women followed a video demonstration of a 30-minute whole-body stretching exercise. Carotid-femoral pulse wave velocity (cf-PWV), augmentation index, LF, peripheral and central BP, and HR were measured before and after the stretching exercise. One bout of a static stretching exercise significantly reduced cf-PWV (t29 = 2.708, P = .011) and HR (t29 = 7.160, P = .000) and increased LF (t29 = 12.248, P < .000). Augmentation index and peripheral and central BP also decreased but did not reach statistical significance. Despite no association found between cf-PWV and LF, the larger increase in LF the subjects had, the larger decrease in cf-PWV they had after exercise (r = 0.500, P = .005). Study findings highlight the potential benefit of a static stretching exercise on central arterial stiffness, an independent predictor of cardiovascular morbidity. Static stretching exercise conducted in the sitting position may be used as an effective intervention to reduce cardiovascular risk after a cardiac event or for patients whose sympathetic function should not be overly activated or whose gaits are not stable.

Voluntary chronic exercise augments in vivo natural immunity in rats.

PubMed

Jonsdottir, I H; Asea, A; Hoffmann, P; Dahlgren, U I; Andersson, B; Hellstrand, K; Thorén, P

1996-05-01

The effect of chronic voluntary exercise on the immune response was studied in spontaneously hypertensive rats. Exercise consisted of voluntary running in wheels for 5 wk, and the mean running distance was 4.2 km/24 h. In vivo cytotoxicity was measured as clearance of injected 51Cr-labeled YAC-1 lymphoma cells from the lungs. The clearance of YAC-1 cells in vivo was significantly increased in runners compared with sedentary controls (P < 0.001). The total number of mononuclear cells in the spleen was significantly decreased in runners compared with controls. Analysis of splenic lymphocyte phenotypes revealed a significantly increased fraction of OX52+/CD5- natural killer cells in runners compared with sedentary controls. In contrast to changes in natural immunity, immunoglobulins G and M levels in serum, the antibody response to antigen in vivo, and the proliferation of splenic T cells in vitro were unchanged. Our data suggest that chronic voluntary exercise augments natural cytotoxicity mechanisms in vivo, whereas splenic T-cell proliferation and the antibody-mediated immune response remain unchanged.

Skeletal Muscle Hypertrophy with Concurrent Exercise Training: Contrary Evidence for an Interference Effect.

PubMed

Murach, Kevin A; Bagley, James R

2016-08-01

Over the last 30+ years, it has become axiomatic that performing aerobic exercise within the same training program as resistance exercise (termed concurrent exercise training) interferes with the hypertrophic adaptations associated with resistance exercise training. However, a close examination of the literature reveals that the interference effect of concurrent exercise training on muscle growth in humans is not as compelling as previously thought. Moreover, recent studies show that, under certain conditions, concurrent exercise may augment resistance exercise-induced hypertrophy in healthy human skeletal muscle. The purpose of this article is to outline the contrary evidence for an acute and chronic interference effect of concurrent exercise on skeletal muscle growth in humans and provide practical literature-based recommendations for maximizing hypertrophy when training concurrently.

Rehabilitation program after mesenchymal stromal cell transplantation augmented by vascularized bone grafts for idiopathic osteonecrosis of the femoral head: a preliminary study.

PubMed

Aoyama, Tomoki; Fujita, Yasuko; Madoba, Katsuyuki; Nankaku, Manabu; Yamada, Minoru; Tomita, Motoko; Goto, Koji; Ikeguchi, Ryosuke; Kakinoki, Ryosuke; Matsuda, Shuichi; Nakamura, Takashi; Toguchida, Junya

2015-03-01

To determine the feasibility and safety of implementing a 12-week rehabilitation program after mesenchymal stromal cell (MSC) transplantation augmented by vascularized bone grafting for idiopathic osteonecrosis (ION) of the femoral head. A prospective case series. University clinical research laboratory. Participants (N=10) with ION who received MSC transplantation augmented by vascularized bone grafting. A 12-week exercise program, which included range-of-motion (ROM) exercises, muscle-strengthening exercises, and aerobic training. Measures of ROM, muscle strength, Timed Up and Go test, and Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) were collected before surgery and again at 6 and 12 months after surgery. All participants completed the 12-week program. External rotation ROM as well as extensor and abductor muscle strength significantly improved 6 months after treatment compared with that before treatment (P<.05). Significant improvements were also seen in physical function, role physical, and bodily pain subgroup scores of the SF-36 (P<.05). No serious adverse events occurred. This study demonstrates the feasibility and safety of a multiplex rehabilitation program after MSC transplantation and provides support for further study on the benefits of rehabilitation programs in regenerative medicine. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effect of nifedipine on choroidal blood flow regulation during isometric exercise.

PubMed

Schmidl, Doreen; Prinz, Ana; Kolodjaschna, Julia; Polska, Elzbieta; Luksch, Alexandra; Fuchsjager-Mayrl, Gabriele; Garhofer, Gerhard; Schmetterer, Leopold

2012-01-25

To determine whether nifedipine, an L-type calcium channel blocker, alters choroidal blood flow (ChBF) regulation during isometric exercise in healthy subjects. The study was carried out in a randomized, placebo-controlled, double-masked, two-way crossover design. Fifteen healthy male subjects were randomly assigned to receive either placebo or nifedipine on two different study days. Subfoveal ChBF was measured with laser Doppler flowmetry while the study participants performed isometric exercise (squatting). This was performed before drug administration and during infusion of nifedipine and placebo, respectively. Mean arterial pressure (MAP) and intraocular pressure (IOP) were measured noninvasively, and ocular perfusion pressure (OPP) was calculated as ⅔ MAP-IOP. MAP and OPP increased significantly during all squatting periods (P < 0.01). The increase in ChBF was less pronounced than the increase in OPP during isometric exercise. Nifedipine did not alter the OPP increase in response to isometric exercise, but it significantly augmented the exercise-induced increase in ChBF (P < 0.001 vs. placebo). Although ChBF increased by a maximum of 14.2% ± 9.2% during the squatting period when placebo was administered, the maximum increase during administration of nifedipine was 23.2% ± 7.2%. In conclusion, the data of the present study suggest that nifedipine augments the ChBF response to an experimental increase in OPP. In addition, it confirms that the choroidal vasculature has a significant regulatory capacity over wide ranges of OPPs during isometric exercise. (ClinicalTrials.gov number, NCT00280462.).

Effect of dead space on breathing stability at exercise in hypoxia.

PubMed

Hermand, Eric; Lhuissier, François J; Richalet, Jean-Paul

2017-12-01

Recent studies have shown that normal subjects exhibit periodic breathing when submitted to concomitant environmental (hypoxia) and physiological (exercise) stresses. A mathematical model including mass balance equations confirmed the short period of ventilatory oscillations and pointed out an important role of dead space in the genesis of these phenomena. Ten healthy subjects performed mild exercise on a cycloergometer in different conditions: rest/exercise, normoxia/hypoxia and no added dead space/added dead space (aDS). Ventilatory oscillations (V˙E peak power) were augmented by exercise, hypoxia and aDS (P<0.001, P<0.001 and P<0.01, respectively) whereas V˙E period was only shortened by exercise (P<0.001), with an 11-s period. aDS also increased V˙E (P<0.001), tidal volume (VT, P<0.001), and slightly augmented PETCO 2 (P<0.05) and the respiratory frequency (P<0.05). These results confirmed our previous model, showing an exacerbation of breathing instability by increasing dead space. This underlines opposite effects observed in heart failure patients and normal subjects, in which added dead space drastically reduced periodic breathing and sleep apneas. It also points out that alveolar ventilation remains very close to metabolic needs and is not affected by an added dead space. Clinical Trial reg. n°: NCT02201875. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of Adherence to Eating Habit and Exercise Components in a Behavioral Weight Control Program.

ERIC Educational Resources Information Center

Zegman, Marilyn A.

Although the augmental value of exercise to behavioral weight control programs has been suggested, demonstration of this value is dependent upon an assessment of adherence to change in eating habits and activity patterns. Self-report measures of adherence were obtained from overweight college women undergoing treatment that involved either dietary…

Efficacy of whey protein supplementation on resistance exercise-induced changes in muscle strength, lean mass, and function in mobility-limited older adults

USDA-ARS?s Scientific Manuscript database

Whey protein supplementation may augment resistance exercise-induced increases in muscle strength and mass. Further studies are required to determine whether this effect extends to functionally compromised older adults. The objectives of the study were to compare the effects of whey protein concent...

Teaching Hands-On Linux Host Computer Security

ERIC Educational Resources Information Center

Shumba, Rose

2006-01-01

In the summer of 2003, a project to augment and improve the teaching of information assurance courses was started at IUP. Thus far, ten hands-on exercises have been developed. The exercises described in this article, and presented in the appendix, are based on actions required to secure a Linux host. Publicly available resources were used to…

Cardiorespiratory Fitness and Atherosclerosis: Recent Data and Future Directions.

PubMed

Mehanna, Emile; Hamik, Anne; Josephson, Richard A

2016-05-01

Historically, the relationship between exercise and the cardiovascular system was viewed as unidirectional, with a disease resulting in exercise limitation and hazard. This article reviews and explores the bidirectional nature, delineating the effects, generally positive, on the cardiovascular system and atherosclerosis. Exercise augments eNOS, affects redox potential, and favorably affects mediators of atherosclerosis including lipids, glucose homeostasis, and inflammation. There are direct effects on the vasculature as well as indirect benefits related to exercise-induced changes in body composition and skeletal muscle. Application of aerobic exercise to specific populations is described, with the hope that this knowledge will move the science forward and improve individual patient outcome.

Cardiorespiratory Fitness and Atherosclerosis: Recent Data and Future Directions

PubMed Central

Mehanna, Emile; Hamik, Anne; Josephson, Richard A

2017-01-01

Historically the relationship between exercise and the cardiovascular system was viewed as unidirectional, with disease resulting in exercise limitation and hazard. This article reviews and explores the bidirectional nature, delineating the effects, generally positive, on the cardiovascular system and atherosclerosis. Exercise augments eNOS, affects redox potential, and favorably affects mediators of atherosclerosis including lipids, glucose homeostasis, and inflammation. There are direct effects on the vasculature as well as indirect benefits related to exercises induced changes in body composition and skeletal muscle. Application of aerobic exercise to specific populations is described, with the hope that this knowledge will move the science forward and improve individual patient outcome. PMID:27005804

Acute dietary nitrate supplementation enhances compensatory vasodilation during hypoxic exercise in older adults.

PubMed

Casey, Darren P; Treichler, David P; Ganger, Charles T; Schneider, Aaron C; Ueda, Kenichi

2015-01-15

We have previously demonstrated that aging reduces the compensatory vasodilator response during hypoxic exercise due to blunted nitric oxide (NO) signaling. Recent evidence suggests that NO bioavailability can be augmented by dietary nitrate through the nitrate-nitrite pathway. Thus we tested the hypothesis that acute dietary nitrate supplementation increases the compensatory vasodilator response to hypoxic exercise, particularly in older adults. Thirteen young (25 ± 1 yr) and 12 older (64 ± 2 yr) adults performed rhythmic forearm exercise at 20% of maximum voluntary contraction during normoxia and hypoxia (∼80% O2 saturation); both before (control) and 3 h after beetroot juice (BR) consumption. Forearm vascular conductance (FVC; ml·min(-1)·100 mmHg(-1)) was calculated from forearm blood flow (ml/min) and blood pressure (mmHg). Compensatory vasodilation was defined as the relative increase in FVC due to hypoxic exercise (i.e., % increase compared with respective normoxic exercise trial). Plasma nitrite was determined from venous blood samples obtained before the control trials and each of the exercise trials (normoxia and hypoxia) after BR. Consumption of BR increased plasma nitrite in both young and older adults (P < 0.001). During the control condition, the compensatory vasodilator response to hypoxic exercise was attenuated in older compared with young adults (3.8 ± 1.7% vs. 14.2 ± 1.2%, P < 0.001). Following BR consumption, compensatory vasodilation did not change in young (13.7 ± 3.3%, P = 0.81) adults but was substantially augmented in older adults (11.4 ± 2.1%, P < 0.01). Our data suggest that acute dietary nitrate supplementation increases the compensatory vasodilator response to hypoxic exercise in older but not young adults. Copyright © 2015 the American Physiological Society.

Contact sensing from force measurements

NASA Technical Reports Server (NTRS)

Bicchi, Antonio; Salisbury, J. K.; Brock, David L.

1993-01-01

This article addresses contact sensing (i.e., the problem of resolving the location of a contact, the force at the interface, and the moment about the contact normals). Called 'intrinsic' contact sensing for the use of internal force and torque measurements, this method allows for practical devices that provide simple, relevant contact information in practical robotic applications. Such sensors have been used in conjunction with robot hands to identify objects, determine surface friction, detect slip, augment grasp stability, measure object mass, probe surfaces, and control collision and for a variety of other useful tasks. This article describes the theoretical basis for their operation and provides a framework for future device design.

Stroke Volume During Concomitant Apnea and Exercise: Influence of Gravity and Venous Return

NASA Astrophysics Data System (ADS)

Hoffmann, Uwe; Drager, Tobias; Steegmanns, Ansgar; Koesterer, Thomas; Linnarsson, Dag

2008-06-01

The responses of the cardiovascular system to intensive exercise (hiP) and combined stimuli by hiP and breath-hold (hiP-BH) for 20 s were examined during changing gravity (parabolic flight) and constant gravity (1g). The basic response to microgravity (μg) during low-intensity exercise was an increase in cardiac output (CO) and stroke volume (SV) as a result of augmented venous return. When onset of hiP was superimposed, the initial augmentation of CO and SV were increased further. In contrast, when BH was added, the increases of CO and SV were slowed. We propose that this was due to a transient increase of the pulmonary blood volume with the combination of μg and BH at large lung volume, creating a temporary imbalance between right ventricular input and left ventricular output. In addition, the BH- induced relative bradycardia may have contributed to a prolongation of the right-to- left indirect ventricular interdependence.

The effects of a multiflavonoid supplement on vascular and hemodynamic parameters following acute exercise.

PubMed

Kappus, Rebecca M; Curry, Chelsea D; McAnulty, Steve; Welsh, Janice; Morris, David; Nieman, David C; Soukup, Jeffrey; Collier, Scott R

2011-01-01

Antioxidants can decrease oxidative stress and combined with acute exercise they may lead to further decreases in blood pressure. The purpose of this study was to investigate the effects of 2 weeks of antioxidant supplementation on vascular distensibility and cardiovascular hemodynamics during postexercise hypotension. Twenty young subjects were randomized to placebo (n = 10) or antioxidant supplementation (n = 10) for two weeks. Antioxidant status, vascular distensibility, and hemodynamics were obtained before, immediately, and 30 minutes after an acute bout of aerobic exercise both before and after supplementation. Two weeks of antioxidant supplementation resulted in a greater systolic blood pressure (SBP) decrease during postexercise hypotension (PEH) and significant decreases in augmentation index versus placebo (12.5% versus 3.5%, resp.). Also ferric-reducing ability of plasma (FRAP) increased significantly (interaction P = 0.024) after supplementation. Supplementation showed an additive effect on PEH associated with increased FRAP values and decreases in systolic blood pressure and augmentation index.

The Effects of a Multiflavonoid Supplement on Vascular and Hemodynamic Parameters following Acute Exercise

PubMed Central

Kappus, Rebecca M.; Curry, Chelsea D.; McAnulty, Steve; Welsh, Janice; Morris, David; Nieman, David C.; Soukup, Jeffrey; Collier, Scott R.

2011-01-01

Antioxidants can decrease oxidative stress and combined with acute exercise they may lead to further decreases in blood pressure. The purpose of this study was to investigate the effects of 2 weeks of antioxidant supplementation on vascular distensibility and cardiovascular hemodynamics during postexercise hypotension. Methods. Twenty young subjects were randomized to placebo (n = 10) or antioxidant supplementation (n = 10) for two weeks. Antioxidant status, vascular distensibility, and hemodynamics were obtained before, immediately, and 30 minutes after an acute bout of aerobic exercise both before and after supplementation. Results. Two weeks of antioxidant supplementation resulted in a greater systolic blood pressure (SBP) decrease during postexercise hypotension (PEH) and significant decreases in augmentation index versus placebo (12.5% versus 3.5%, resp.). Also ferric-reducing ability of plasma (FRAP) increased significantly (interaction P = 0.024) after supplementation. Conclusion. Supplementation showed an additive effect on PEH associated with increased FRAP values and decreases in systolic blood pressure and augmentation index. PMID:22191012

Heart rate variability and aerobic fitness.

PubMed

De Meersman, R E

1993-03-01

Heart rate variability, a noninvasive marker of parasympathetic activity, diminishes with aging and is augmented after exercise training. Whether habitual exercise over time can attenuate this loss is unknown. This cross-sectional investigation compared 72 male runners, aged 15 to 83 to 72 age- and weight-matched sedentary control subjects for the amplitude of their heart rate variability. Heart rate variability was assessed during rest while subjects were breathing at a rate of 6 breaths per minute and at an augmented tidal volume (tidal volume = 30% of vital capacity). Fitness levels were assessed with on-line, open-circuit spirometry while subjects were performing an incremental stress test. Overall results between the two groups showed that the physically active group had significantly higher fitness levels (p < 0.001), which were associated with significantly higher levels of heart rate variability, when compared with their sedentary counterparts (p < 0.001). These findings provide suggestive evidence for habitual aerobic exercise as a beneficial modulator of heart rate variability in an aging population.

Robot-Assisted Guitar Hero for Finger Rehabilitation after Stroke

PubMed Central

Taheri, Hossein; Rowe, Justin B.; Gardner, David; Chan, Vicky; Reinkensmeyer, David J.; Wolbrecht, Eric T.

2014-01-01

This paper describes the design and testing of a robotic device for finger therapy after stroke: FINGER (Finger Individuating Grasp Exercise Robot). FINGER makes use of stacked single degree-of-freedom mechanisms to assist subjects in moving individual fingers in a naturalistic grasping pattern through much of their full range of motion. The device has a high bandwidth of control (−3dB at approximately 8 Hz) and is backdriveable. These characteristics make it capable of assisting in grasping tasks that require precise timing. We therefore used FINGER to assist individuals with a stroke (n = 8) and without impairment (n = 4) in playing a game similar to Guitar Hero©. The subjects attempted to move their fingers to target positions at times specified by notes that were graphically streamed to popular music. We show here that by automatically adjusting the robot gains, it is possible to use FINGER to modulate the subject’s success rate at the game, across a range of impairment levels. Modulating success rates did not alter the stroke subject’s effort, although the unimpaired subjects exerted more force when they were made less successful. We also present a novel measure of finger individuation that can be assessed as individuals play Guitar Hero with FINGER. The results demonstrate the ability of FINGER to provide controlled levels of assistance during an engaging computer game, and to quantify finger individuation after stroke. PMID:23366783

Making Self-Help More Helpful: A Randomized Controlled Trial of the Impact of Augmenting Self-Help Materials with Implementation Intentions on Promoting the Effective Self-Management of Anxiety Symptoms

ERIC Educational Resources Information Center

Varley, Rachel; Webb, Thomas L.; Sheeran, Paschal

2011-01-01

Objective: The effectiveness of self-help materials may be constrained by failures to undertake recommended exercises or to deploy the techniques that one has learned at the critical moment. The present randomized controlled trial investigated whether augmenting self-help materials with if-then plans (or implementation intentions) could overcome…

Sympathetic activation in exercise is not dependent on muscle acidosis. Direct evidence from studies in metabolic myopathies

NASA Technical Reports Server (NTRS)

Vissing, J.; Vissing, S. F.; MacLean, D. A.; Saltin, B.; Quistorff, B.; Haller, R. G.; Blomqvist, C. G. (Principal Investigator)

1998-01-01

Muscle acidosis has been implicated as a major determinant of reflex sympathetic activation during exercise. To test this hypothesis we studied sympathetic exercise responses in metabolic myopathies in which muscle acidosis is impaired or augmented during exercise. As an index of reflex sympathetic activation to muscle, microneurographic measurements of muscle sympathetic nerve activity (MSNA) were obtained from the peroneal nerve. MSNA was measured during static handgrip exercise at 30% of maximal voluntary contraction force to exhaustion in patients in whom exercise-induced muscle acidosis is absent (seven myophosphorylase deficient patients; MD [McArdle's disease], and one patient with muscle phosphofructokinase deficiency [PFKD]), augmented (one patient with mitochondrial myopathy [MM]), or normal (five healthy controls). Muscle pH was monitored by 31P-magnetic resonance spectroscopy during handgrip exercise in the five control subjects, four MD patients, and the MM and PFKD patients. With handgrip to exhaustion, the increase in MSNA over baseline (bursts per minute [bpm] and total activity [%]) was not impaired in patients with MD (17+/-2 bpm, 124+/-42%) or PFKD (65 bpm, 307%), and was not enhanced in the MM patient (24 bpm, 131%) compared with controls (17+/-4 bpm, 115+/-17%). Post-handgrip ischemia studied in one McArdle patient, caused sustained elevation of MSNA above basal suggesting a chemoreflex activation of MSNA. Handgrip exercise elicited an enhanced drop in muscle pH of 0.51 U in the MM patient compared with the decrease in controls of 0.13+/-0.02 U. In contrast, muscle pH increased with exercise in MD by 0.12+/-0.05 U and in PFKD by 0.01 U. In conclusion, patients with glycogenolytic, glycolytic, and oxidative phosphorylation defects show normal muscle sympathetic nerve responses to static exercise. These findings indicate that muscle acidosis is not a prerequisite for sympathetic activation in exercise.

[Municipal Health Councils: activity and representation of grassroots communities].

PubMed

Gerschman, Silvia

2004-01-01

This article was based on the results of research concerning health policy in municipalities that achieved the most extensive development of decentralization and innovation in the State of Rio de Janeiro, Brazil. The study applied a questionnaire for health system users' representatives in Municipal Health Councils. The central issues were: the Councils' political role; social control by the Councils, viewed as surveillance by organized society over government actions; the nature of social representation exercised by the Council members; and the type of mandate they serve. Community representatives in the Councils reinforce aspects pertaining to the exercise of representation in unequal societies. There is a predominance of a differentiated elite consisting of older males with more schooling and higher income than the community average. The notion of "social control" as the basis for the Councils is difficult for the members to grasp. Exercise of representation is diffuse, occurring by way of designation by community associations, election in assemblies, or designation by institutional health policy agencies.

Acute effects of repeated bouts of aerobic exercise on arterial stiffness after glucose ingestion.

PubMed

Kobayashi, Ryota; Hashimoto, Yuto; Hatakeyama, Hiroyuki; Okamoto, Takanobu

2018-03-22

The aim of this study was to investigate the acute repeated bouts of aerobic exercise decrease leg arterial stiffness. However, the influence of repeated bouts of aerobic exercise on arterial stiffness after glucose ingestion is unknown. The present study investigates the acute effects of repeated bouts of aerobic exercise on arterial stiffness after the 75-g oral glucose tolerance test (OGTT). Ten healthy young men (age, 23.2 ± 0.9 years) performed repeated bouts of aerobic exercise trial (RE, 65% peak oxygen uptake; two 15 min bouts of cycling performed 20 min apart) and control trial (CON, seated and resting in a quiet room) at 80 min before the 75-g OGTT on separate days in a randomized, controlled crossover fashion. Carotid-femoral (aortic) and femoral-ankle (leg) pulse wave velocity, carotid augmentation index, brachial and ankle blood pressure, heart rate and blood glucose and insulin levels were measured before (baseline) and 30, 60 and 120 min after the 75-g OGTT. Leg pulse wave velocity, ankle systolic blood pressure and blood glucose levels increased from baseline after the 75-g OGTT in the CON trial, but not in the RE trial. The present findings indicate that acute repeated bouts of aerobic exercise before glucose ingestion suppress increases in leg arterial stiffness following glucose ingestion. RE trial repeated bouts of aerobic exercise trial; CON trial control trial; BG blood glucose; VO 2peak peak oxygen uptake; PWV Pulse wave velocity; AIx carotid augmentation index; BP blood pressure; HR heart rate; CVs coefficients of variation; RPE Ratings of perceived exertion; SE standard error.

Altered Arterial Stiffness and Subendocardial Viability Ratio in Young Healthy Light Smokers after Acute Exercise

PubMed Central

Doonan, Robert J.; Scheffler, Patrick; Yu, Alice; Egiziano, Giordano; Mutter, Andrew; Bacon, Simon; Carli, Franco; Daskalopoulos, Marios E.; Daskalopoulou, Stella S.

2011-01-01

Background Studies showed that long-standing smokers have stiffer arteries at rest. However, the effect of smoking on the ability of the vascular system to respond to increased demands (physical stress) has not been studied. The purpose of this study was to estimate the effect of smoking on arterial stiffness and subendocardial viability ratio, at rest and after acute exercise in young healthy individuals. Methods/Results Healthy light smokers (n = 24, pack-years = 2.9) and non-smokers (n = 53) underwent pulse wave analysis and carotid-femoral pulse wave velocity measurements at rest, and 2, 5, 10, and 15 minutes following an exercise test to exhaustion. Smokers were tested, 1) after 12h abstinence from smoking (chronic condition) and 2) immediately after smoking one cigarette (acute condition). At rest, chronic smokers had higher augmentation index and lower aortic pulse pressure than non-smokers, while subendocardial viability ratio was not significantly different. Acute smoking increased resting augmentation index and decreased subendocardial viability ratio compared with non-smokers, and decreased subendocardial viability ratio compared with the chronic condition. After exercise, subendocardial viability ratio was lower, and augmentation index and aortic pulse pressure were higher in non-smokers than smokers in the chronic and acute conditions. cfPWV rate of recovery of was greater in non-smokers than chronic smokers after exercise. Non-smokers were also able to achieve higher workloads than smokers in both conditions. Conclusion Chronic and acute smoking appears to diminish the vascular response to physical stress. This can be seen as an impaired ‘vascular reserve’ or a blunted ability of the blood vessels to accommodate the changes required to achieve higher workloads. These changes were noted before changes in arterial stiffness or subendocardial viability ratio occurred at rest. Even light smoking in young healthy individuals appears to have harmful effects on vascular function, affecting the ability of the vascular bed to respond to increased demands. PMID:22028821

Closed-Loop Task Difficulty Adaptation during Virtual Reality Reach-to-Grasp Training Assisted with an Exoskeleton for Stroke Rehabilitation

PubMed Central

Grimm, Florian; Naros, Georgios; Gharabaghi, Alireza

2016-01-01

Stroke patients with severe motor deficits of the upper extremity may practice rehabilitation exercises with the assistance of a multi-joint exoskeleton. Although this technology enables intensive task-oriented training, it may also lead to slacking when the assistance is too supportive. Preserving the engagement of the patients while providing “assistance-as-needed” during the exercises, therefore remains an ongoing challenge. We applied a commercially available seven degree-of-freedom arm exoskeleton to provide passive gravity compensation during task-oriented training in a virtual environment. During this 4-week pilot study, five severely affected chronic stroke patients performed reach-to-grasp exercises resembling activities of daily living. The subjects received virtual reality feedback from their three-dimensional movements. The level of difficulty for the exercise was adjusted by a performance-dependent real-time adaptation algorithm. The goal of this algorithm was the automated improvement of the range of motion. In the course of 20 training and feedback sessions, this unsupervised adaptive training concept led to a progressive increase of the virtual training space (p < 0.001) in accordance with the subjects' abilities. This learning curve was paralleled by a concurrent improvement of real world kinematic parameters, i.e., range of motion (p = 0.008), accuracy of movement (p = 0.01), and movement velocity (p < 0.001). Notably, these kinematic gains were paralleled by motor improvements such as increased elbow movement (p = 0.001), grip force (p < 0.001), and upper extremity Fugl-Meyer-Assessment score from 14.3 ± 5 to 16.9 ± 6.1 (p = 0.026). Combining gravity-compensating assistance with adaptive closed-loop feedback in virtual reality provides customized rehabilitation environments for severely affected stroke patients. This approach may facilitate motor learning by progressively challenging the subject in accordance with the individual capacity for functional restoration. It might be necessary to apply concurrent restorative interventions to translate these improvements into relevant functional gains of severely motor impaired patients in activities of daily living. PMID:27895550

Closed-Loop Task Difficulty Adaptation during Virtual Reality Reach-to-Grasp Training Assisted with an Exoskeleton for Stroke Rehabilitation.

PubMed

Grimm, Florian; Naros, Georgios; Gharabaghi, Alireza

2016-01-01

Stroke patients with severe motor deficits of the upper extremity may practice rehabilitation exercises with the assistance of a multi-joint exoskeleton. Although this technology enables intensive task-oriented training, it may also lead to slacking when the assistance is too supportive. Preserving the engagement of the patients while providing "assistance-as-needed" during the exercises, therefore remains an ongoing challenge. We applied a commercially available seven degree-of-freedom arm exoskeleton to provide passive gravity compensation during task-oriented training in a virtual environment. During this 4-week pilot study, five severely affected chronic stroke patients performed reach-to-grasp exercises resembling activities of daily living. The subjects received virtual reality feedback from their three-dimensional movements. The level of difficulty for the exercise was adjusted by a performance-dependent real-time adaptation algorithm. The goal of this algorithm was the automated improvement of the range of motion. In the course of 20 training and feedback sessions, this unsupervised adaptive training concept led to a progressive increase of the virtual training space ( p < 0.001) in accordance with the subjects' abilities. This learning curve was paralleled by a concurrent improvement of real world kinematic parameters, i.e., range of motion ( p = 0.008), accuracy of movement ( p = 0.01), and movement velocity ( p < 0.001). Notably, these kinematic gains were paralleled by motor improvements such as increased elbow movement ( p = 0.001), grip force ( p < 0.001), and upper extremity Fugl-Meyer-Assessment score from 14.3 ± 5 to 16.9 ± 6.1 ( p = 0.026). Combining gravity-compensating assistance with adaptive closed-loop feedback in virtual reality provides customized rehabilitation environments for severely affected stroke patients. This approach may facilitate motor learning by progressively challenging the subject in accordance with the individual capacity for functional restoration. It might be necessary to apply concurrent restorative interventions to translate these improvements into relevant functional gains of severely motor impaired patients in activities of daily living.

Pokémon-Go: Why Augmented Reality Games Offer Insights for Enhancing Public Health Interventions on Obesity-Related Diseases.

PubMed

Wong, Ming Chao; Turner, Paul; MacIntyre, Kate; Yee, Kwang Chien

2017-01-01

Stimulating widespread interests of the population to participate in behavioural changes through information and technology has been an aim of much health informatics research. The recent widespread participation of the augmented reality game Pokémon Go which encourages exercises, provides significant insights into the potential of information technology to improve healthcare intervention on obesity-related disease. Does Pokémon Go point to another way of achieving health benefits using mobile devices? This paper analyses the features of Pokémon Go in relation to potential health benefits. This paper suggests from the perspective of a user on changes to the game that potentially could help with obesity, mental health cardiovascular health and vitamin D deficiencies. While the impact of augmented reality games on improving exercises might be substantial, the question of sustainability and likely long-term health outcomes remain debatable. The rapid uptake of Pokémon Go by the population around the world, however, should serve as a useful lesson for information and technological design to improve outcomes obesity-related diseases in the future.

Thermogenic responsiveness to β-adrenergic stimulation is augmented in exercising versus sedentary adults: role of oxidative stress

PubMed Central

Bell, Christopher; Stob, Nicole R; Seals, Douglas R

2006-01-01

β-Adrenergic receptor (β-AR) modulation of resting and postprandial energy expenditure (EE) is augmented in regularly exercising compared with sedentary adults, but the underlying physiological mechanisms are unknown. Differences in thermogenic responsiveness to β-AR stimulation, perhaps secondary to reactive oxygen species (ROS) bioactivity, may be involved. To determine habitual exercise-related differences in β-AR thermogenic responsiveness and the possible influence of ROS, we measured the percentage increase in EE (ΔEE%; indirect calorimetry, ventilated hood method) above resting EE in response to non-specific β-AR stimulation (intravenous isoproterenol (isoprenaline): 6, 12 and 24 ng (kg fat-free mass)−1 min−1) in 25 sedentary (11 males; 51 ± 4 years; body mass index 25.0 ± 0.8 kg m−2, maximal oxygen uptake 29 ± 1 ml kg−1 min−1 (mean ±s.e.m.)) and 14 habitually aerobic exercising (9 males, 46 ± 6 years, 23.1 ± 0.7 kg m−2, 44 ± 3 ml kg−1 min−1) healthy adults under normal (control) conditions and during acute intravenous administration of a potent antioxidant, ascorbic acid (vitamin C; 0.04 g (kg fat-free mass)−1). ΔEE% was greater (P= 0.02) in the habitually exercising (8.6 ± 1.2, 12.9 ± 1.2, 20.0 ± 1.4) versus sedentary (6.3 ± 0.7, 10.4 ± 0.8, 16.0 ± 1.0) adults. Ascorbic acid increased (P= 0.01) ΔEE% only in the sedentary adults (to 9.5 ± 0.9, 12.4 ± 0.7, 18.5 ± 0.8), abolishing baseline group differences. ΔEE% was not related to the amount of body fat, sex, or any other baseline characteristic. Thermogenic responsiveness to β-AR stimulation is augmented in habitually exercising adults. The mechanism is ascorbic acid dependent, suggesting that it may be linked to decreased ROS bioactivity. Our findings advance a novel mechanism by which habitual physical activity may modulate EE in humans, with potential implications for energy balance and body weight control. PMID:16308351

[Basic mechanisms of QRS voltage changes on ECG of healthy subjects during the exercise test].

PubMed

Saltykova, M M

2015-01-01

Electrocardiography is the most commonly used technique for detection stress-induced myocardial ischemia. However, the sensitivity of ECG-criteria is not high. One of the major problem is the difficulty in differentiating ECG changes caused by various factors. The aim of this study was to evaluate the dependence of the QRS voltage changes during exercise on parameters of central hemodynamics, gender particularities and to reveal mechanisms causing these changes. To eliminate the effect of changes in cardiomyocytes transmembrane potentials under the influence of the neurotransmitters of the autonomic nervous system during stepwise increasing exercises and/or due to a lack of ATP results from inadequate myocardial blood flow only healthy subjects not older than 35 years were included in the study (7 men and 7 women) and only periods of ventricular depolarization (QRS complex on the ECG) were included in the analysis. We compared the changes of QRS waves during exercise sessions with two upper and one lower limbs in both men and women. The exercise load was twice bigger in exercise with one leg relative to exercise with two arms. Responses of heart rate and systolic arterial pressure were similar. Amplitude of S-wave in left chest leads significantly increased in both sessions without significant difference between augmentations in the sessions and in groups of men and women. Significant relationship between the S wave augmentation and the peak systolic arterial pressure were revealed. Furthermore, the QRS changes during the exercise with vertical and a horizontal torso position were compared to assess the impact of diastolic arterial pressure and displacement of the diaphragm and heart rotation due to increase of abdominal pressure during the last steps of exercise. The obtained results allow us to exclude the impact of the heart position and size changes, as well as the exercise load on S-wave changes and make a conclusion about the dependence of this parameter on the value of systolic blood pressure.

Exercise augmentation compared to usual care for post traumatic stress disorder: a randomised controlled trial (the REAP study: Randomised Exercise Augmentation for PTSD).

PubMed

Rosenbaum, Simon; Nguyen, Dang; Lenehan, Tom; Tiedemann, Anne; van der Ploeg, Hidde P; Sherrington, Catherine

2011-07-22

The physical wellbeing of people with mental health conditions can often be overlooked in order to treat the primary mental health condition as a priority. Exercise however, can potentially improve both the primary psychiatric condition as well as physical measures that indicate risk of other conditions such as diabetes mellitus and cardiovascular disease. Evidence supports the role of exercise as an important component of treatment for depression and anxiety, yet no randomised controlled trials (RCT's) have been conducted to evaluate the use of exercise in the treatment of people with post traumatic stress disorder (PTSD). This RCT will investigate the effects of structured, progressive exercise on PTSD symptoms, functional ability, body composition, physical activity levels, sleep patterns and medication usage. Eighty participants with a Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) diagnosis of PTSD will be recruited. Participants will have no contraindications to exercise and will be cognitively able to provide consent to participate in the study. The primary outcome measures will be PTSD symptoms, measured through the PTSD Checklist Civilian (PCL-C) scale. Secondary outcome measures will assess depression and anxiety, mobility and strength, body composition, physical activity levels, sleep patterns and medication usage. All outcomes will be assessed by a health or exercise professional masked to group allocation at baseline and 12 weeks after randomisation. The intervention will be a 12 week individualised program, primarily involving resistance exercises with the use of exercise bands. A walking component will also be incorporated. Participants will complete one supervised session per week, and will be asked to perform at least two other non-supervised exercise sessions per week. Both intervention and control groups will receive all usual non-exercise interventions including psychotherapy, pharmaceutical interventions and group therapy. This study will determine the effect of an individualised and progressive exercise intervention on PTSD symptoms, depression and anxiety, mobility and strength, body composition, physical activity levels, sleep patterns and medication usage among people with a DSM-IV diagnosis of PTSD. ACTRN12610000579099.

Robotic Technology Efforts at the NASA/Johnson Space Center

NASA Technical Reports Server (NTRS)

Diftler, Ron

2017-01-01

The NASA/Johnson Space Center has been developing robotic systems in support of space exploration for more than two decades. The goal of the Center’s Robotic Systems Technology Branch is to design and build hardware and software to assist astronauts in performing their mission. These systems include: rovers, humanoid robots, inspection devices and wearable robotics. Inspection systems provide external views of space vehicles to search for surface damage and also maneuver inside restricted areas to verify proper connections. New concepts in human and robotic rovers offer solutions for navigating difficult terrain expected in future planetary missions. An important objective for humanoid robots is to relieve the crew of “dull, dirty or dangerous” tasks allowing them more time to perform their important science and exploration missions. Wearable robotics one of the Center’s newest development areas can provide crew with low mass exercise capability and also augment an astronaut’s strength while wearing a space suit.This presentation will describe the robotic technology and prototypes developed at the Johnson Space Center that are the basis for future flight systems. An overview of inspection robots will show their operation on the ground and in-orbit. Rovers with independent wheel modules, crab steering, and active suspension are able to climb over large obstacles, and nimbly maneuver around others. Humanoid robots, including the First Humanoid Robot in Space: Robonaut 2, demonstrate capabilities that will lead to robotic caretakers for human habitats in space, and on Mars. The Center’s Wearable Robotics Lab supports work in assistive and sensing devices, including exoskeletons, force measuring shoes, and grasp assist gloves.

Robotic Technology Efforts at the NASA/Johnson Space Center

NASA Technical Reports Server (NTRS)

Diftler, Ron

2017-01-01

The NASA/Johnson Space Center has been developing robotic systems in support of space exploration for more than two decades. The goal of the Center's Robotic Systems Technology Branch is to design and build hardware and software to assist astronauts in performing their mission. These systems include: rovers, humanoid robots, inspection devices and wearable robotics. Inspection systems provide external views of space vehicles to search for surface damage and also maneuver inside restricted areas to verify proper connections. New concepts in human and robotic rovers offer solutions for navigating difficult terrain expected in future planetary missions. An important objective for humanoid robots is to relieve the crew of "dull, dirty or dangerous" tasks allowing them more time to perform their important science and exploration missions. Wearable robotics one of the Center's newest development areas can provide crew with low mass exercise capability and also augment an astronaut's strength while wearing a space suit. This presentation will describe the robotic technology and prototypes developed at the Johnson Space Center that are the basis for future flight systems. An overview of inspection robots will show their operation on the ground and in-orbit. Rovers with independent wheel modules, crab steering, and active suspension are able to climb over large obstacles, and nimbly maneuver around others. Humanoid robots, including the First Humanoid Robot in Space: Robonaut 2, demonstrate capabilities that will lead to robotic caretakers for human habitats in space, and on Mars. The Center's Wearable Robotics Lab supports work in assistive and sensing devices, including exoskeletons, force measuring shoes, and grasp assist gloves.

New evidence for therapies in stroke rehabilitation.

PubMed

Dobkin, Bruce H; Dorsch, Andrew

2013-06-01

Neurologic rehabilitation aims to reduce impairments and disabilities so that persons with serious stroke can return to participation in usual self-care and daily activities as independently as feasible. New strategies to enhance recovery draw from a growing understanding of how types of training, progressive task-related practice of skills, exercise for strengthening and fitness, neurostimulation, and drug and biological manipulations can induce adaptations at multiple levels of the nervous system. Recent clinical trials provide evidence for a range of new interventions to manage walking, reach and grasp, aphasia, visual field loss, and hemi-inattention.

The turn of the screw: an exercise in protein secondary structure.

PubMed

Pikaart, Michael

2011-01-01

An exercise using simple paper strips to illustrate protein helical and sheet secondary structures is presented. Drawing on the rich historical context of the use of physical models in protein biochemistry by early practitioners, in particular Linus Pauling, the purpose of this activity is to cultivate in students a hands-on, intuitive sense of protein secondary structure and to complement the common computer-based structural portrayals often used in teaching biochemistry. As students fold these paper strips into model secondary structures, they will better grasp how intramolecular hydrogen bonds form in the folding of a polypeptide into secondary structure, and how these hydrogen bonds direct the overall shape of helical and sheet structures, including the handedness of the α-helix and the difference between right- and the left-handed twist. Copyright © 2010 Wiley Periodicals, Inc.

Design of a wearable hand exoskeleton for exercising flexion/extension of the fingers.

PubMed

Jo, Inseong; Lee, Jeongsoo; Park, Yeongyu; Bae, Joonbum

2017-07-01

In this paper, design of a wearable hand exoskeleton system for exercising flexion/extension of the fingers, is proposed. The exoskeleton was designed with a simple and wearable structure to aid finger motions in 1 degree of freedom (DOF). A hand grasping experiment by fully-abled people was performed to investigate general hand flexion/extension motions and the polynomial curve of general hand motions was obtained. To customize the hand exoskeleton for the user, the polynomial curve was adjusted to the joint range of motion (ROM) of the user and the optimal design of the exoskeleton structure was obtained using the optimization algorithm. A prototype divided into two parts (one part for the thumb, the other for rest fingers) was actuated by only two linear motors for compact size and light weight.

Cognitive Benefits of Exercise Intervention.

PubMed

Archer, T; Ricci, S; Massoni, F; Ricci, L; Rapp-Ricciardi, M

2016-01-01

Exercise, as a potent epigenetic regulator, implies the potential to counteract pathophysiological processes and alterations in most cardiovascular/respiratory cells and tissues not withstanding a paucity of understanding the underlying molecular mechanisms and doseresponse relationships. In the present account, the assets accruing from physical exercise and its influence upon executive functioning are examined. Under conditions of neuropsychiatric and neurologic ill-health, age-related deterioration of functional and biomarker indicators during healthy and disordered trajectories, neuroimmune and affective unbalance, and epigenetic pressures, exercise offers a large harvest of augmentations in health and well-being. Both animal models and human studies support the premise of manifest gains from regular exercise within several domains, besides cognitive function and mood, notably as the agency of a noninvasive, readily available therapeutic intervention.

Mitochondrial antioxidative capacity regulates muscle glucose uptake in the conscious mouse: effect of exercise and diet.

PubMed

Kang, Li; Lustig, Mary E; Bonner, Jeffrey S; Lee-Young, Robert S; Mayes, Wesley H; James, Freyja D; Lin, Chien-Te; Perry, Christopher G R; Anderson, Ethan J; Neufer, P Darrell; Wasserman, David H

2012-10-15

The objective of this study was to test the hypothesis that exercise-stimulated muscle glucose uptake (MGU) is augmented by increasing mitochondrial reactive oxygen species (mtROS) scavenging capacity. This hypothesis was tested in genetically altered mice fed chow or a high-fat (HF) diet that accelerates mtROS formation. Mice overexpressing SOD2 (sod2(Tg)), mitochondria-targeted catalase (mcat(Tg)), and combined SOD2 and mCAT (mtAO) were used to increase mtROS scavenging. mtROS was assessed by the H(2)O(2) emitting potential (JH(2)O(2)) in muscle fibers. sod2(Tg) did not decrease JH(2)O(2) in chow-fed mice, but decreased JH(2)O(2) in HF-fed mice. mcat(Tg) and mtAO decreased JH(2)O(2) in both chow- and HF-fed mice. In parallel, the ratio of reduced to oxidized glutathione (GSH/GSSG) was unaltered in sod2(Tg) in chow-fed mice, but was increased in HF-fed sod2(Tg) and both chow- and HF-fed mcat(Tg) and mtAO. Nitrotyrosine, a marker of NO-dependent, reactive nitrogen species (RNS)-induced nitrative stress, was decreased in both chow- and HF-fed sod2(Tg), mcat(Tg), and mtAO mice. This effect was not changed with exercise. Kg, an index of MGU was assessed using 2-[(14)C]-deoxyglucose during exercise. In chow-fed mice, sod2(Tg), mcat(Tg), and mtAO increased exercise Kg compared with wild types. Exercise Kg was also augmented in HF-fed sod2(Tg) and mcat(Tg) mice but unchanged in HF-fed mtAO mice. In conclusion, mtROS scavenging is a key regulator of exercise-mediated MGU and this regulation depends on nutritional state.

Effect of static and dynamic exercise on heart rate and blood pressure variabilities.

PubMed

González-Camarena, R; Carrasco-Sosa, S; Román-Ramos, R; Gaitán-González, M J; Medina-Bañuelos, V; Azpiroz-Leehan, J

2000-10-01

This study examines the effect of static and dynamic leg exercises on heart rate variability (HRV) and blood pressure variability (BPV) in humans. 10 healthy male subjects were studied at rest, during static exercise performed at 30% of maximal voluntary contraction (SX30), and during dynamic cycling exercises done at 30% of VO2max (DX30) and at 60% of VO2max (DX60). Respiration, heart rate, and blood pressure signals were digitized to analyze temporal and spectral parameters involving short and overall indexes (SD, deltaRANGE, RMSSD, Total power), power of the low (LF), middle (MF), and high (HF) frequency components, and the baroreceptor sensitivity by the alphaMF index. During SX30, indexes of HRV as SD, deltaRANGE, Total power, and MF in absolute units increased in relation with rest values and were significantly higher (P < 0.001) than during DX30 and DX60; HF during SX30, in normalized and absolute units, was not different of the rest condition but was higher (P < 0.001) than HF during DX30 and DX60. Parameters of BPV as SD and deltaRANGE increased (P < 0.001) during both type of exercises, and significant (P < 0.01) increments were observed on MF during SX30 and DX30; systolic HF was attenuated during DX30 (P < 0.05), whereas diastolic HF was augmented during DX60 (P < 0.001). Compared with rest condition, the alphaMF index decreased (P < 0.01) only during dynamic exercises. Because HRV and BPV response is different when induced by static or dynamic exercise, differences in the autonomic activity can be advised. Instead of the vagal withdrawal and sympathetic augmentation observed during dynamic exercise, the increase in the overall HRV and the MF component during static exercise suggest an increased activity of both autonomic branches.

Effect of resistance exercise under conditions of reduced blood insulin on AMPKα Ser485/491 inhibitory phosphorylation and AMPK pathway activation.

PubMed

Kido, Kohei; Yokokawa, Takumi; Ato, Satoru; Sato, Koji; Fujita, Satoshi

2017-08-01

Insulin stimulates skeletal muscle glucose uptake via activation of the protein kinase B/Akt (Akt) pathway. Recent studies suggest that insulin downregulates AMP-activated protein kinase (AMPK) activity via Ser485/491 phosphorylation of the AMPK α-subunit. Thus lower blood insulin concentrations may induce AMPK signal activation. Acute exercise is one method to stimulate AMPK activation; however, no study has examined the relationship between blood insulin levels and acute resistance exercise-induced AMPK pathway activation. Based on previous findings, we hypothesized that the acute resistance exercise-induced AMPK pathway activation would be augmented by disruptions in insulin secretion through a decrease in AMPKα Ser485/491 inhibitory phosphorylation. To test the hypothesis, 10-wk-old male Sprague-Dawley rats were administered the toxin streptozotocin (STZ; 55 mg/kg) to destroy the insulin secreting β-cells. Three days postinjection, the right gastrocnemius muscle from STZ and control rats was subjected to resistance exercise by percutaneous electrical stimulation. Animals were killed 0, 1, or 3 h later; activation of the Akt/AMPK and downstream pathways in the muscle tissue was analyzed by Western blotting and real-time PCR. Notably, STZ rats showed a significant decrease in basal Akt and AMPKα Ser485/491 phosphorylation, but substantial exercise-induced increases in both AMPKα Thr172 and acetyl-CoA carboxylase (ACC) Ser79 phosphorylation were observed. Although no significant impact on resistance exercise-induced Akt pathway activation or glucose uptake was found, resistance exercise-induced peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1 α (PGC-1α) gene expression was augmented by STZ treatment. Collectively, these data suggest that circulating insulin levels may regulate acute resistance exercise-induced AMPK pathway activation and AMPK-dependent gene expression relating to basal AMPKα Ser485/491 phosphorylation. Copyright © 2017 the American Physiological Society.

Interaction of vitamin E and exercise training on oxidative stress and antioxidant enzyme activities in rat skeletal muscles.

PubMed

Chang, Chen-Kang; Huang, Hui-Yu; Tseng, Hung-Fu; Hsuuw, Yan-Der; Tso, Tim K

2007-01-01

It has been shown that free radicals are increased during intensive exercise. We hypothesized that vitamin E (vit E) deficiency, which will increase oxidative stress, would augment the training-induced adaptation of antioxidant enzymes. This study investigated the interaction effect of vit E and exercise training on oxidative stress markers and activities of antioxidant enzymes in red quadriceps and white gastrocnemius of rats in a 2x2 design. Thirty-two male rats were divided into trained vit E-adequate, trained vit E-deficient, untrained vit E-adequate, and untrained vit E-deficient groups. The two trained groups swam 6 h/day, 6 days/week for 8 weeks. The two vit E-deficient groups consumed vit E-free diet for 8 weeks. Vitamin E-training interaction effect was significant on thiobarbituric acid reactive substances (TBARSs), glutathione peroxidase (GPX), and superoxide dismutase (SOD) in both muscles. The trained vit E-deficient group showed the highest TBARS and GPX activity and the lowest SOD activity in both muscles. A significant vit E effect on glutathione reductase and catalase was present in both muscles. Glutathione reductase and catalase activities were significantly lower in the two vit E-adequate groups combined than in the two vit E-deficient groups combined in both muscles. This study shows that vit E status and exercise training have interactive effect on oxidative stress and GPX and SOD activities in rat skeletal muscles. Vitamin E deprivation augmented the exercise-induced elevation in GPX activity while inhibiting exercise-induced SOD activity, possibly through elevated oxidative stress.

Exercise as an adjunct treatment for opiate agonist treatment: review of the current research and implementation strategies.

PubMed

Weinstock, Jeremiah; Wadeson, Heather K; VanHeest, Jaci L

2012-01-01

Opiate dependence is a significant public health concern linked to poor quality of life, comorbid psychiatric disorders, and high costs to society. Current opiate agonist treatments are an effective but limited intervention. Adjunctive interventions could improve and augment opiate agonist treatment outcomes, including drug abstinence, quality of life, and physical health. This article reviews exercise as an adjunctive intervention for opiate agonist treatment, especially in regards to improving mood and overall quality of life, while reducing other substance use. Poor adherence and dropout frequently prevent many individuals from garnering the many physical and mental health benefits of exercise. Strategies for implementing an exercise intervention, including safety considerations, are discussed.

An analysis of the input-output properties of neuroprosthetic hand grasps.

PubMed

Memberg, W D; Crago, P E

2000-01-01

We measured the input-output properties of the hand grasps of 14 individuals with tetraplegia at the C5/C6 level who had received an implanted upper limb neuroprosthesis. The data provide a quantitative description of grasp-opening and grasp-force control with neuroprosthetic hand grasp systems. Static properties were estimated by slowly ramping the command (input) from 0 to 100%. A hand-held sensor monitored the outputs: grasp force and grasp opening. Trials were performed at different wrist positions, with two different-sized objects being held, and with both grasp modes (lateral and palmar grasps). Larger forces were produced when grasping larger objects, and greater opening was achieved with the wrist in flexion. Although active grasp force increased with wrist extension, it was not significant statistically. Lateral grasp produced larger forces than the palmar grasp. The command range can be divided into a portion that controls grasp opening and a portion that controls grasp force. The portion controlling force increased with spacer size, but did not depend significantly on grasp mode or wrist position. The force-command relationships were more linear than the position-command relationships. Grasp opening decreased significantly over a one-year period, while no significant change in grasp force was observed. These quantitative descriptions of neuroprosthetic hand grasps under varying conditions provide useful information about output capabilities that can be used to gauge the effectiveness of different control schemes and to design future control systems.

Alpha-1 Antitrypsin Deficiency (Inherited Emphysema)

MedlinePlus

... often given once a week. There are three brands of augmentation therapy. They include: • Prolastin® • Aralast™ • Zemaira™ • In addition to medicines, the management of Alpha-1 related emphysema includes: • Exercise and ...

Reaching and Grasping a Glass of Water by Locked-In ALS Patients through a BCI-Controlled Humanoid Robot

PubMed Central

Spataro, Rossella; Chella, Antonio; Allison, Brendan; Giardina, Marcello; Sorbello, Rosario; Tramonte, Salvatore; Guger, Christoph; La Bella, Vincenzo

2017-01-01

Locked-in Amyotrophic Lateral Sclerosis (ALS) patients are fully dependent on caregivers for any daily need. At this stage, basic communication and environmental control may not be possible even with commonly used augmentative and alternative communication devices. Brain Computer Interface (BCI) technology allows users to modulate brain activity for communication and control of machines and devices, without requiring a motor control. In the last several years, numerous articles have described how persons with ALS could effectively use BCIs for different goals, usually spelling. In the present study, locked-in ALS patients used a BCI system to directly control the humanoid robot NAO (Aldebaran Robotics, France) with the aim of reaching and grasping a glass of water. Four ALS patients and four healthy controls were recruited and trained to operate this humanoid robot through a P300-based BCI. A few minutes training was sufficient to efficiently operate the system in different environments. Three out of the four ALS patients and all controls successfully performed the task with a high level of accuracy. These results suggest that BCI-operated robots can be used by locked-in ALS patients as an artificial alter-ego, the machine being able to move, speak and act in his/her place. PMID:28298888

Concluding remarks: nutritional strategies to support the adaptive response to prolonged exercise training.

PubMed

van Loon, Luc J C; Tipton, Kevin D

2013-01-01

Nutrition plays a key role in allowing the numerous training hours to be translated into useful adaptive responses of various tissues in the individual athlete. Research over the last decade has shown many examples of the impact of dietary interventions to modulate the skeletal muscle adaptive response to prolonged exercise training. Proper nutritional coaching should be applied throughout both training and competition, each with their specific requirements regarding nutrient provision. Such dietary support will improve exercise training efficiency and, as such, further increase performance capacity. Here, we provide an overview on the properties of various nutritional interventions that may be useful to support the adaptive response to exercise training and competition and, as such, to augment exercise training efficiency. Copyright © 2013 Nestec Ltd., Vevey/S. Karger AG, Basel.

Modular mechatronic system for stationary bicycles interfaced with virtual environment for rehabilitation.

PubMed

Ranky, Richard G; Sivak, Mark L; Lewis, Jeffrey A; Gade, Venkata K; Deutsch, Judith E; Mavroidis, Constantinos

2014-06-05

Cycling has been used in the rehabilitation of individuals with both chronic and post-surgical conditions. Among the challenges with implementing bicycling for rehabilitation is the recruitment of both extremities, in particular when one is weaker or less coordinated. Feedback embedded in virtual reality (VR) augmented cycling may serve to address the requirement for efficacious cycling; specifically recruitment of both extremities and exercising at a high intensity. In this paper a mechatronic rehabilitation bicycling system with an interactive virtual environment, called Virtual Reality Augmented Cycling Kit (VRACK), is presented. Novel hardware components embedded with sensors were implemented on a stationary exercise bicycle to monitor physiological and biomechanical parameters of participants while immersing them in an augmented reality simulation providing the user with visual, auditory and haptic feedback. This modular and adaptable system attaches to commercially-available stationary bicycle systems and interfaces with a personal computer for simulation and data acquisition processes. The complete bicycle system includes: a) handle bars based on hydraulic pressure sensors; b) pedals that monitor pedal kinematics with an inertial measurement unit (IMU) and forces on the pedals while providing vibratory feedback; c) off the shelf electronics to monitor heart rate and d) customized software for rehabilitation. Bench testing for the handle and pedal systems is presented for calibration of the sensors detecting force and angle. The modular mechatronic kit for exercise bicycles was tested in bench testing and human tests. Bench tests performed on the sensorized handle bars and the instrumented pedals validated the measurement accuracy of these components. Rider tests with the VRACK system focused on the pedal system and successfully monitored kinetic and kinematic parameters of the rider's lower extremities. The VRACK system, a virtual reality mechatronic bicycle rehabilitation modular system was designed to convert most bicycles in virtual reality (VR) cycles. Preliminary testing of the augmented reality bicycle system was successful in demonstrating that a modular mechatronic kit can monitor and record kinetic and kinematic parameters of several riders.

Post-exercise effects on aortic wave reflection derived from wave separation analysis in young- to middle-aged pre-hypertensives and hypertensives.

PubMed

Millen, Aletta M E; Woodiwiss, Angela J; Norton, Gavin R

2016-07-01

Decreases in brachial blood pressure (BP) may occur for several hours following a bout of exercise. Although aortic backward waves predict cardiovascular damage independent of brachial BP, whether decreases in aortic backward waves also occur post-exercise in young-to-middle-aged hypertensives, the extent to which these changes exceed brachial BP changes, and the best method of identifying these changes is uncertain. We examined aortic function at baseline and 15-min post-exercise in 20 pre-hypertensive or hypertensive men and women (age 45 ± 7 years). Central aortic pressure, forward (Pf) and backward (Pb) wave pressures, the reflection index (RI) and augmentation pressure (AP) and index (AIx) were determined using applanation tonometry, and SphygmoCor software. Decreases in central aortic (p < 0.001) but not brachial systolic BP and pulse pressure (PP) occurred post-exercise. In addition, decreases in post-exercise (baseline versus post-exercise) Pb (19 ± 4 vs 13 ± 3 mm Hg p < 0.0001), RI (72.9 ± 22.1 vs 47.6 ± 12.8 %, p < 0.0001), AIx (26.3 ± 10.8 vs 7.8 ± 11.6 %, p < 0.0001) and AP (9.9 ± 3.9 vs 2.8 ± 3.9 mm Hg, p < 0.0001), but not Pf, were noted. However, decreases in AIx were not correlated with decreases in Pb, and whilst decreases in aortic PP correlated with decreases in Pb (p < 0.0001), no correlations were noted with decreases in AP or AIx. In young-to-middle-aged pre-hypertensive and hypertensive individuals, aortic backward waves decrease post-exercise; this change is not reflected in brachial BP measurements and is poorly indexed by measures of pressure augmentation.

Effect of pencil grasp on the speed and legibility of handwriting in children.

PubMed

Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl; Chau, Tom

2012-01-01

Pencil grasps other than the dynamic tripod may be functional for handwriting. This study examined the impact of grasp on handwriting speed and legibility. We videotaped 120 typically developing fourth-grade students while they performed a writing task. We categorized the grasps they used and evaluated their writing for speed and legibility using a handwriting assessment. Using linear regression analysis, we examined the relationship between grasp and handwriting. We documented six categories of pencil grasp: four mature grasp patterns, one immature grasp pattern, and one alternating grasp pattern. Multiple linear regression results revealed no significant effect for mature grasp on either legibility or speed. Pencil grasp patterns did not influence handwriting speed or legibility in this sample of typically developing children. This finding adds to the mounting body of evidence that alternative grasps may be acceptable for fast and legible handwriting. Copyright © 2012 by the American Occupational Therapy Association, Inc.

Grasp-Based Functional Coupling Between Reach- and Grasp-Related Components of Forelimb Muscle Activity

PubMed Central

Geed, Shashwati; van Kan, Peter L. E.

2017-01-01

How are appropriate combinations of forelimb muscles selected during reach-to-grasp movements in the presence of neuromotor redundancy and important task-related constraints? The authors tested whether grasp type or target location preferentially influence the selection and synergistic coupling between forelimb muscles during reach-to-grasp movements. Factor analysis applied to 14–20 forelimb electromyograms recorded from monkeys performing reach-to-grasp tasks revealed 4–6 muscle components that showed transport/preshape- or grasp-related features. Weighting coefficients of transport/preshape-related components demonstrated strongest similarities for reaches that shared the same grasp type rather than the same target location. Scaling coefficients of transport/preshape- and grasp-related components showed invariant temporal coupling. Thus, grasp type influenced strongly both transport/preshape- and grasp-related muscle components, giving rise to grasp-based functional coupling between forelimb muscles. PMID:27589010

H-GRASP: the feasibility of an upper limb home exercise program monitored by phone for individuals post stroke

PubMed Central

Simpson, Lisa A.; Eng, Janice J.; Chan, May

2017-01-01

Abstract Purpose: To investigate the feasibility of a phone-monitored home exercise program for the upper limb following stroke. Methods: A pre-post double baseline repeated measures design was used. Participants completed an 8-week home exercise program that included behavioural strategies to promote greater use of the affected upper limb. Participants were monitored weekly by therapists over the phone. The following feasibility outcomes were collected: Process (e.g. recruitment rate); Resources (e.g. exercise adherence rate); Management (e.g. therapist monitoring) and Scientific (e.g. safety, effect sizes). Clinical outcomes included: The Chedoke Arm and Hand Inventory, Motor Activity Log, grip strength and the Canadian Occupational Performance Measure. Results: Eight individuals with stroke were recruited and six participants completed the exercise program. All but one of the six participants met the exercise target of 60 minutes/day, 6 days/week. Participants were stable across the baseline period. The following post-treatment effect sizes were observed: CAHAI (0.944, p = 0.046); MALQ (0.789, p = 0.03) grip strength (0.947, p = 0.046); COPM (0.789, p = 0.03). Improvements were maintained at three and six month follow ups. Conclusions: Community dwelling individuals with stroke may benefit from a phone-monitored upper limb home exercise program that includes behavioural strategies that promote transfer of exercise gains into daily upper limb use.Implications for RehabilitationA repetitive, task-oriented home exercise program that utilizes telephone supervision may be an effective method for the treatment of the upper limb following strokeThis program is best suited for individuals with mild to moderate level impairment and experience a sufficient level of challenge from the exercisesAn exercise program that includes behavioural strategies may promote transfer of exercise gains into greater use of the affected upper limb during daily activities PMID:27017890

Robot-Assisted End-Effector-Based Stair Climbing for Cardiopulmonary Exercise Testing: Feasibility, Reliability, and Repeatability.

PubMed

Stoller, Oliver; Schindelholz, Matthias; Hunt, Kenneth J

2016-01-01

Neurological impairments can limit the implementation of conventional cardiopulmonary exercise testing (CPET) and cardiovascular training strategies. A promising approach to provoke cardiovascular stress while facilitating task-specific exercise in people with disabilities is feedback-controlled robot-assisted end-effector-based stair climbing (RASC). The aim of this study was to evaluate the feasibility, reliability, and repeatability of augmented RASC-based CPET in able-bodied subjects, with a view towards future research and applications in neurologically impaired populations. Twenty able-bodied subjects performed a familiarisation session and 2 consecutive incremental CPETs using augmented RASC. Outcome measures focussed on standard cardiopulmonary performance parameters and on accuracy of work rate tracking (RMSEP-root mean square error). Criteria for feasibility were cardiopulmonary responsiveness and technical implementation. Relative and absolute test-retest reliability were assessed by intraclass correlation coefficients (ICC), standard error of the measurement (SEM), and minimal detectable change (MDC). Mean differences, limits of agreement, and coefficients of variation (CoV) were estimated to assess repeatability. All criteria for feasibility were achieved. Mean V'O2peak was 106±9% of predicted V'O2max and mean HRpeak was 99±3% of predicted HRmax. 95% of the subjects achieved at least 1 criterion for V'O2max, and the detection of the sub-maximal ventilatory thresholds was successful (ventilatory anaerobic threshold 100%, respiratory compensation point 90% of the subjects). Excellent reliability was found for peak cardiopulmonary outcome measures (ICC ≥ 0.890, SEM ≤ 0.60%, MDC ≤ 1.67%). Repeatability for the primary outcomes was good (CoV ≤ 0.12). RASC-based CPET with feedback-guided exercise intensity demonstrated comparable or higher peak cardiopulmonary performance variables relative to predicted values, achieved the criteria for V'O2max, and allowed determination of sub-maximal ventilatory thresholds. The reliability and repeatability were found to be high. There is potential for augmented RASC to be used for exercise testing and prescription in populations with neurological impairments who would benefit from repetitive task-specific training.

Robot-Assisted End-Effector-Based Stair Climbing for Cardiopulmonary Exercise Testing: Feasibility, Reliability, and Repeatability

PubMed Central

Stoller, Oliver; Schindelholz, Matthias; Hunt, Kenneth J.

2016-01-01

Background Neurological impairments can limit the implementation of conventional cardiopulmonary exercise testing (CPET) and cardiovascular training strategies. A promising approach to provoke cardiovascular stress while facilitating task-specific exercise in people with disabilities is feedback-controlled robot-assisted end-effector-based stair climbing (RASC). The aim of this study was to evaluate the feasibility, reliability, and repeatability of augmented RASC-based CPET in able-bodied subjects, with a view towards future research and applications in neurologically impaired populations. Methods Twenty able-bodied subjects performed a familiarisation session and 2 consecutive incremental CPETs using augmented RASC. Outcome measures focussed on standard cardiopulmonary performance parameters and on accuracy of work rate tracking (RMSEP−root mean square error). Criteria for feasibility were cardiopulmonary responsiveness and technical implementation. Relative and absolute test-retest reliability were assessed by intraclass correlation coefficients (ICC), standard error of the measurement (SEM), and minimal detectable change (MDC). Mean differences, limits of agreement, and coefficients of variation (CoV) were estimated to assess repeatability. Results All criteria for feasibility were achieved. Mean V′O2peak was 106±9% of predicted V′O2max and mean HRpeak was 99±3% of predicted HRmax. 95% of the subjects achieved at least 1 criterion for V′O2max, and the detection of the sub-maximal ventilatory thresholds was successful (ventilatory anaerobic threshold 100%, respiratory compensation point 90% of the subjects). Excellent reliability was found for peak cardiopulmonary outcome measures (ICC ≥ 0.890, SEM ≤ 0.60%, MDC ≤ 1.67%). Repeatability for the primary outcomes was good (CoV ≤ 0.12). Conclusions RASC-based CPET with feedback-guided exercise intensity demonstrated comparable or higher peak cardiopulmonary performance variables relative to predicted values, achieved the criteria for V′O2max, and allowed determination of sub-maximal ventilatory thresholds. The reliability and repeatability were found to be high. There is potential for augmented RASC to be used for exercise testing and prescription in populations with neurological impairments who would benefit from repetitive task-specific training. PMID:26849137

Aerobic exercise training reduces arterial stiffness in metabolic syndrome.

PubMed

Donley, David A; Fournier, Sara B; Reger, Brian L; DeVallance, Evan; Bonner, Daniel E; Olfert, I Mark; Frisbee, Jefferson C; Chantler, Paul D

2014-06-01

The metabolic syndrome (MetS) is associated with a threefold increase risk of cardiovascular disease (CVD) mortality partly due to increased arterial stiffening. We compared the effects of aerobic exercise training on arterial stiffening/mechanics in MetS subjects without overt CVD or type 2 diabetes. MetS and healthy control (Con) subjects underwent 8 wk of exercise training (ExT; 11 MetS and 11 Con) or remained inactive (11 MetS and 10 Con). The following measures were performed pre- and postintervention: radial pulse wave analysis (applanation tonometry) was used to measure augmentation pressure and index, central pressures, and an estimate of myocardial efficiency; arterial stiffness was assessed from carotid-femoral pulse-wave velocity (cfPWV, applanation tonometry); carotid thickness was assessed from B-mode ultrasound; and peak aerobic capacity (gas exchange) was performed in the seated position. Plasma matrix metalloproteinases (MMP) and CVD risk (Framingham risk score) were also assessed. cfPWV was reduced (P < 0.05) in MetS-ExT subjects (7.9 ± 0.6 to 7.2 ± 0.4 m/s) and Con-ExT (6.6 ± 1.8 to 5.6 ± 1.6 m/s). Exercise training reduced (P < 0.05) central systolic pressure (116 ± 5 to 110 ± 4 mmHg), augmentation pressure (9 ± 1 to 7 ± 1 mmHg), augmentation index (19 ± 3 to 15 ± 4%), and improved myocardial efficiency (155 ± 8 to 168 ± 9), but only in the MetS group. Aerobic capacity increased (P < 0.05) in MetS-ExT (16.6 ± 1.0 to 19.9 ± 1.0) and Con-ExT subjects (23.8 ± 1.6 to 26.3 ± 1.6). MMP-1 and -7 were correlated with cfPWV, and both MMP-1 and -7 were reduced post-ExT in MetS subjects. These findings suggest that some of the pathophysiological changes associated with MetS can be improved after aerobic exercise training, thereby lowering their cardiovascular risk. Copyright © 2014 the American Physiological Society.

Aerobic exercise training reduces arterial stiffness in metabolic syndrome

PubMed Central

Donley, David A.; Fournier, Sara B.; Reger, Brian L.; DeVallance, Evan; Bonner, Daniel E.; Olfert, I. Mark; Frisbee, Jefferson C.

2014-01-01

The metabolic syndrome (MetS) is associated with a threefold increase risk of cardiovascular disease (CVD) mortality partly due to increased arterial stiffening. We compared the effects of aerobic exercise training on arterial stiffening/mechanics in MetS subjects without overt CVD or type 2 diabetes. MetS and healthy control (Con) subjects underwent 8 wk of exercise training (ExT; 11 MetS and 11 Con) or remained inactive (11 MetS and 10 Con). The following measures were performed pre- and postintervention: radial pulse wave analysis (applanation tonometry) was used to measure augmentation pressure and index, central pressures, and an estimate of myocardial efficiency; arterial stiffness was assessed from carotid-femoral pulse-wave velocity (cfPWV, applanation tonometry); carotid thickness was assessed from B-mode ultrasound; and peak aerobic capacity (gas exchange) was performed in the seated position. Plasma matrix metalloproteinases (MMP) and CVD risk (Framingham risk score) were also assessed. cfPWV was reduced (P < 0.05) in MetS-ExT subjects (7.9 ± 0.6 to 7.2 ± 0.4 m/s) and Con-ExT (6.6 ± 1.8 to 5.6 ± 1.6 m/s). Exercise training reduced (P < 0.05) central systolic pressure (116 ± 5 to 110 ± 4 mmHg), augmentation pressure (9 ± 1 to 7 ± 1 mmHg), augmentation index (19 ± 3 to 15 ± 4%), and improved myocardial efficiency (155 ± 8 to 168 ± 9), but only in the MetS group. Aerobic capacity increased (P < 0.05) in MetS-ExT (16.6 ± 1.0 to 19.9 ± 1.0) and Con-ExT subjects (23.8 ± 1.6 to 26.3 ± 1.6). MMP-1 and -7 were correlated with cfPWV, and both MMP-1 and -7 were reduced post-ExT in MetS subjects. These findings suggest that some of the pathophysiological changes associated with MetS can be improved after aerobic exercise training, thereby lowering their cardiovascular risk. PMID:24744384

The prefrontal oxygenation and ventilatory responses at start of one-legged cycling exercise have relation to central command.

PubMed

Asahara, Ryota; Matsukawa, Kanji; Ishii, Kei; Liang, Nan; Endo, Kana

2016-11-01

When performing exercise arbitrarily, activation of central command should start before the onset of exercise, but when exercise is forced to start with cue, activation of central command should be delayed. We examined whether the in-advance activation of central command influenced the ventilatory response and reflected in the prefrontal oxygenation, by comparing the responses during exercise with arbitrary and cued start. The breath-by-breath respiratory variables and the prefrontal oxygenated-hemoglobin concentration (Oxy-Hb) were measured during one-legged cycling. Minute ventilation (V̇e) at the onset of arbitrary one-legged cycling was augmented to a greater extent than cued cycling, while end-tidal carbon dioxide tension (ETco 2 ) decreased irrespective of arbitrary or cued start. Symmetric increase in the bilateral prefrontal Oxy-Hb occurred before and at the onset of arbitrary one-legged cycling, whereas such an increase was absent with cued start. The time course and magnitude of the increased prefrontal oxygenation were not influenced by the extent of subjective rating of perceived exertion and were the same as those of the prefrontal oxygenation during two-legged cycling previously reported. Mental imagery or passive performance of the one-legged cycling increased V̇e and decreased ETco 2 Neither intervention, however, augmented the prefrontal Oxy-Hb. The changes in ETco 2 could not explain the prefrontal oxygenation response during voluntary or passive one-legged cycling. Taken together, it is likely that the in-advance activation of central command influenced the ventilatory response by enhancing minute ventilation at the onset of one-legged cycling exercise and reflected in the preexercise increase in the prefrontal oxygenation. Copyright © 2016 the American Physiological Society.

Ventilation Increases with Lower Extremity Venous Occlusion in Young Adults

PubMed Central

Keller-Ross, Manda L.; Cowl, Andrielle L.; Cross, Troy; Johnson, Bruce D.; Olson, Thomas P.

2015-01-01

Introduction Venous distention via sub-systolic occlusion of the lower limbs may augment ventilation via stimulation of group III/IV afferent neurons. Purpose The purpose of this study was to examine the ventilatory response to graded lower extremity venous occlusion during exercise in healthy adults. Methods Nineteen adults (9 men, 25±5 yr) completed two visits. Visit 1: a maximal cycle ergometry exercise test. Visit 2 included a 30% peak workload cycle exercise with randomized inflations of bilateral thigh pressure tourniquets to 20, 40, 60, 80, 100 mmHg for 2 min each, separated by 2 min of deflation. Three min of cycling occurred prior to cuffing (CTL). Expired minute ventilation (VE), whole body gas exchange, rating of perceived exertion and dyspnea were measured during each session. Results VE increased significantly from the control condition (exercise only, control, CTL) to each occlusion pressure (p<0.05) with the greatest increase at 100 mmHg (CTL to 100 mmHg: 31.5±6.6 to 40.1±10.7 L/min). Respiratory rate (RR) increased as well (CTL to 100 mmHg: 24.8±6.0 to 30.9±11.5 breaths/min, p<0.05, condition effect) with no change in tidal volume (p>0.05). Tidal volume to inspiratory time (VT/TI) increased significantly from the CTL condition to each occlusion pressure (CTL to 100 mmHg: 1.5±0.3 to 1.8±0.4 L/min, p<0.05, all pressures). Dyspnea and RPE increased with all occlusion pressures from CTL exercise (p<0.05, all pressures). Conclusion Our findings suggest that mild-to-moderate venous occlusion of the lower extremity evokes a tachypneic breathing pattern which, in turn, augments VE and perceived breathing effort during exercise. PMID:26484951

Exercise training augments the dynamic heart rate response to vagal but not sympathetic stimulation in rats.

PubMed

Mizuno, Masaki; Kawada, Toru; Kamiya, Atsunori; Miyamoto, Tadayoshi; Shimizu, Shuji; Shishido, Toshiaki; Smith, Scott A; Sugimachi, Masaru

2011-04-01

We examined the transfer function of autonomic heart rate (HR) control in anesthetized sedentary and exercise-trained (16 wk, treadmill for 1 h, 5 times/wk at 15 m/min and 15-degree grade) rats for comparison to HR variability assessed in the conscious resting state. The transfer function from sympathetic stimulation to HR response was similar between groups (gain, 4.2 ± 1.5 vs. 4.5 ± 1.5 beats·min(-1)·Hz(-1); natural frequency, 0.07 ± 0.01 vs. 0.08 ± 0.01 Hz; damping coefficient, 1.96 ± 0.55 vs. 1.69 ± 0.15; and lag time, 0.7 ± 0.1 vs. 0.6 ± 0.1 s; sedentary vs. exercise trained, respectively, means ± SD). The transfer gain from vagal stimulation to HR response was 6.1 ± 3.0 in the sedentary and 9.7 ± 5.1 beats·min(-1)·Hz(-1) in the exercise-trained group (P = 0.06). The corner frequency (0.11 ± 0.05 vs. 0.17 ± 0.09 Hz) and lag time (0.1 ± 0.1 vs. 0.2 ± 0.1 s) did not differ between groups. When the sympathetic transfer gain was averaged for very-low-frequency and low-frequency bands, no significant group effect was observed. In contrast, when the vagal transfer gain was averaged for very-low-frequency, low-frequency, and high-frequency bands, exercise training produced a significant group effect (P < 0.05 by two-way, repeated-measures ANOVA). These findings suggest that, in the frequency domain, exercise training augments the dynamic HR response to vagal stimulation but not sympathetic stimulation, regardless of the frequency bands.

Functional classification of grasp strategies used by hemiplegic patients

PubMed Central

Roby-Brami, Agnès; Robertson, Johanna; Roche, Nicolas

2017-01-01

This study aimed to identify and qualify grasp-types used by patients with stroke and determine the clinical parameters that could explain the use of each grasp. Thirty-eight patients with chronic stroke-related hemiparesis and a range of motor and functional capacities (17 females and 21 males, aged 25–78), and 10 healthy subjects were included. Four objects were used (tissue packet, teaspoon, bottle and tennis ball). Participants were instructed to “grasp the object as if you are going to use it”. Three trials were video-recorded for each object. A total of 456 grasps were analysed and rated using a custom-designed Functional Grasp Scale. Eight grasp-types were identified from the analysis: healthy subjects used Multi-pulpar, Pluri-digital, Lateral-pinch and Palmar grasps (Standard Grasps). Patients used the same grasps with in addition Digito-palmar, Raking, Ulnar and Interdigital grasps (Alternative Grasps). Only patients with a moderate or relatively good functional ability used Standard grasps. The correlation and regression analyses showed this was conditioned by sufficient finger and elbow extensor strength (Pluri-digital grasp); thumb extensor and wrist flexor strength (Lateral pinch) or in forearm supinator strength (Palmar grasp). By contrast, the patients who had severe impairment used Alternative grasps that did not involve the thumb. These strategies likely compensate specific impairments. Regression and correlation analyses suggested that weakness had a greater influence over grasp strategy than spasticity. This would imply that treatment should focus on improving hand strength and control although reducing spasticity may be useful in some cases. PMID:29125855

Atypical depressive symptoms as a predictor of treatment response to exercise in Major Depressive Disorder.

PubMed

Rethorst, Chad D; Tu, Jian; Carmody, Thomas J; Greer, Tracy L; Trivedi, Madhukar H

2016-08-01

Effective treatment of Major Depressive Disorder (MDD) will require the development of alternative treatments and the ability for clinicians to match patients with the treatment likely to produce the greatest effect. We examined atypical depression subtype as a predictor of treatment response to aerobic exercise augmentation in persons with non-remitted MDD. Our results revealed a small-to-moderate effect, particularly in a group assigned to high-dose exercise (semi-partial eta-squared =0.0335, p=0.0735), indicating that those with atypical depression tended to have larger treatment response to exercise. Through this hypothesis-generating analysis, we indicate the need for research to examine depression subtype, along with other demographic, clinical and biological factors as predictors of treatment response to exercise. Copyright © 2016 Elsevier B.V. All rights reserved.

Challenging Students' Intuitions—the Influence of a Tangible Model of Virus Assembly on Students' Conceptual Reasoning About the Process of Self-Assembly

NASA Astrophysics Data System (ADS)

Larsson, Caroline; Tibell, Lena A. E.

2015-10-01

A well-ordered biological complex can be formed by the random motion of its components, i.e. self-assemble. This is a concept that incorporates issues that may contradict students' everyday experiences and intuitions. In previous studies, we have shown that a tangible model of virus self-assembly, used in a group exercise, helps students to grasp the process of self-assembly and in particular the facet "random molecular collision". The present study investigates how and why the model and the group exercise facilitate students' learning of this particular facet. The data analysed consist of audio recordings of six group exercises ( n = 35 university students) and individual semi-structured interviews ( n = 5 university students). The analysis is based on constructivist perspectives of learning, a combination of conceptual change theory and learning with external representations. Qualitative analysis indicates that perceived counterintuitive aspects of the process created a cognitive conflict within learners. The tangible model used in the group exercises facilitated a conceptual change in their understanding of the process. In particular, the tangible model appeared to provide cues and possible explanations and functioned as an "eye-opener" and a "thinking tool". Lastly, the results show signs of emotions also being important elements for successful accommodation.

Data-driven grasp synthesis using shape matching and task-based pruning.

PubMed

Li, Ying; Fu, Jiaxin L; Pollard, Nancy S

2007-01-01

Human grasps, especially whole-hand grasps, are difficult to animate because of the high number of degrees of freedom of the hand and the need for the hand to conform naturally to the object surface. Captured human motion data provides us with a rich source of examples of natural grasps. However, for each new object, we are faced with the problem of selecting the best grasp from the database and adapting it to that object. This paper presents a data-driven approach to grasp synthesis. We begin with a database of captured human grasps. To identify candidate grasps for a new object, we introduce a novel shape matching algorithm that matches hand shape to object shape by identifying collections of features having similar relative placements and surface normals. This step returns many grasp candidates, which are clustered and pruned by choosing the grasp best suited for the intended task. For pruning undesirable grasps, we develop an anatomically-based grasp quality measure specific to the human hand. Examples of grasp synthesis are shown for a variety of objects not present in the original database. This algorithm should be useful both as an animator tool for posing the hand and for automatic grasp synthesis in virtual environments.

Influence of complementing a robotic upper limb rehabilitation system with video games on the engagement of the participants: a study focusing on muscle activities.

PubMed

Li, Chong; Rusák, Zoltán; Horváth, Imre; Ji, Linhong

2014-12-01

Efficacious stroke rehabilitation depends not only on patients' medical treatment but also on their motivation and engagement during rehabilitation exercises. Although traditional rehabilitation exercises are often mundane, technology-assisted upper-limb robotic training can provide engaging and task-oriented training in a natural environment. The factors that influence engagement, however, are not fully understood. This paper therefore studies the relationship between engagement and muscle activities as well as the influencing factors of engagement. To this end, an experiment was conducted using a robotic upper limb rehabilitation system with healthy individuals in three training exercises: (a) a traditional exercise, which is typically used for training the grasping function, (b) a tracking exercise, currently used in robot-assisted stroke patient rehabilitation for fine motor movement, and (c) a video game exercise, which is a proliferating approach of robot-assisted rehabilitation enabling high-level active engagement of stroke patients. These exercises differ not only in the characteristics of the motion that they use but also in their method of triggering engagement. To measure the level of engagement, we used facial expressions, motion analysis of the arm movements, and electromyography. The results show that (a) the video game exercise could engage the participants for a longer period than the other two exercises, (b) the engagement level decreased when the participants became too familiar with the exercises, and (c) analysis of normalized root mean square in electromyographic data indicated that muscle activities were more intense when the participants are engaged. This study shows that several sub-factors on engagement, such as versatility of feedback, cognitive tasks, and competitiveness, may influence engagement more than the others. To maintain a high level of engagement, the rehabilitation system needs to be adaptive, providing different exercises to engage the participants.

Enhancing Neuroplasticity to Augment Cognitive Remediation in Schizophrenia.

PubMed

Jahshan, Carol; Rassovsky, Yuri; Green, Michael F

2017-01-01

There is a burgeoning need for innovative treatment strategies to improve the cognitive deficits in schizophrenia. Cognitive remediation (CR) is effective at the group level, but the variability in treatment response is large. Given that CR may depend on intact neuroplasticity to produce cognitive gains, it is reasonable to combine it with strategies that harness patients' neuroplastic potential. In this review, we discuss two non-pharmacological approaches that can enhance neuroplasticity and possibly augment the effects of CR in schizophrenia: physical exercise and transcranial direct current stimulation (tDCS). Substantial body of evidence supports the beneficial effect of physical exercise on cognition, and a handful of studies in schizophrenia have shown that physical exercise in conjunction with CR has a larger impact on cognition than CR alone. Physical exercise is thought to stimulate neuroplasticity through the regulation of central growth factors, and current evidence points to brain-derived neurotrophic factor as the potential underlying mechanism through which physical exercise might enhance the effectiveness of CR. tDCS has emerged as a potential tool for cognitive enhancement and seems to affect the cellular mechanisms involved in long-term potentiation (LTP). A few reports have demonstrated the feasibility of integrating tDCS with CR in schizophrenia, but there are insufficient data to determine if this multimodal approach leads to incremental performance gain in patients. Larger randomized controlled trials are necessary to understand the mechanisms of the combined tDCS-CR intervention. Future research should take advantage of new developments in neuroplasticity paradigms to examine the effects of these interventions on LTP.

Purkinje cells signal hand shape and grasp force during reach-to-grasp in the monkey.

PubMed

Mason, Carolyn R; Hendrix, Claudia M; Ebner, Timothy J

2006-01-01

The cerebellar cortex and nuclei play important roles in the learning, planning, and execution of reach-to-grasp and prehensile movements. However, few studies have investigated the signals carried by cerebellar neurons during reach-to-grasp, particularly signals relating to target object properties, hand shape, and grasp force. In this study, the simple spike discharge of 77 Purkinje cells was recorded as two rhesus monkeys reached and grasped 16 objects. The objects varied systematically in volume, shape, and orientation and each was grasped at five different force levels. Linear multiple regression analyses showed the simple spike discharge was significantly modulated in relation to objects and force levels. Object related modulation occurred preferentially during reach or early in the grasp and was linearly related to grasp aperture. The simple spike discharge was positively correlated with grasp force during both the reach and the grasp. There was no significant interaction between object and grasp force modulation, supporting previous kinematic findings that grasp kinematics and force are signaled independently. Singular value decomposition (SVD) was used to quantify the temporal patterns in the simple spike discharge. Most cells had a predominant discharge pattern that remained relatively constant across object grasp dimensions and force levels. A single predominant simple spike discharge pattern that spans reach and grasp and accounts for most of the variation (>60%) is consistent with the concept that the cerebellum is involved with synergies underlying prehension. Therefore Purkinje cells are involved with the signaling of prehension, providing independent signals for hand shaping and grasp force.

Blood pressure and calf muscle oxygen extraction during plantar flexion exercise in peripheral artery disease.

PubMed

Luck, J Carter; Miller, Amanda J; Aziz, Faisal; Radtka, John F; Proctor, David N; Leuenberger, Urs A; Sinoway, Lawrence I; Muller, Matthew D

2017-07-01

Peripheral artery disease (PAD) is an atherosclerotic vascular disease that affects 200 million people worldwide. Although PAD primarily affects large arteries, it is also associated with microvascular dysfunction, an exaggerated blood pressure (BP) response to exercise, and high cardiovascular mortality. We hypothesized that fatiguing plantar flexion exercise that evokes claudication elicits a greater reduction in skeletal muscle oxygenation (SmO 2 ) and a higher rise in BP in PAD compared with age-matched healthy subjects, but low-intensity steady-state plantar flexion elicits similar responses between groups. In the first experiment, eight patients with PAD and eight healthy controls performed fatiguing plantar flexion exercise (from 0.5 to 7 kg for up to 14 min). In the second experiment, seven patients with PAD and seven healthy controls performed low-intensity plantar flexion exercise (2.0 kg for 14 min). BP, heart rate (HR), and SmO 2 were measured continuously using near-infrared spectroscopy (NIRS). SmO 2 is the ratio of oxygenated hemoglobin to total hemoglobin, expressed as a percent. At fatigue, patients with PAD had a greater increase in mean arterial BP (18 ± 2 vs. vs. 10 ± 2 mmHg, P = 0.029) and HR (14 ± 2 vs. 6 ± 2 beats/min, P = 0.033) and a greater reduction in SmO 2 (-54 ± 10 vs. -12 ± 4%, P = 0.001). However, both groups had similar physiological responses to low-intensity, nonpainful plantar flexion exercise. These data suggest that patients with PAD have altered oxygen uptake and/or utilization during fatiguing exercise coincident with an augmented BP response. NEW & NOTEWORTHY In this laboratory study, patients with peripheral artery disease performed plantar flexion exercise in the supine posture until symptoms of claudication occurred. Relative to age- and sex-matched healthy subjects we found that patients had a higher blood pressure response, a higher heart rate response, and a greater reduction in skeletal muscle oxygenation as determined by near-infrared spectroscopy. Our data suggest that muscle ischemia contributes to the augmented exercise pressor reflex in peripheral artery disease. Copyright © 2017 the American Physiological Society.

Muscle contraction duration and fibre recruitment influence blood flow and oxygen consumption independent of contractile work during steady-state exercise in humans.

PubMed

Richards, Jennifer C; Crecelius, Anne R; Kirby, Brett S; Larson, Dennis G; Dinenno, Frank A

2012-06-01

We tested the hypothesis that, among conditions of matched contractile work, shorter contraction durations and greater muscle fibre recruitment result in augmented skeletal muscle blood flow and oxygen consumption ( ) during steady-state exercise in humans. To do so, we measured forearm blood flow (FBF; Doppler ultrasound) during 4 min of rhythmic hand-grip exercise in 24 healthy young adults and calculated forearm oxygen consumption ( ) via blood samples obtained from a catheter placed in retrograde fashion into a deep vein draining the forearm muscle. In protocol 1 (n = 11), subjects performed rhythmic isometric hand-grip exercise at mild and moderate intensities during conditions in which time-tension index (isometric analogue of work) was held constant but contraction duration was manipulated. In this protocol, shorter contraction durations led to greater FBF (184 ± 25 versus 164 ± 25 ml min(-1)) and (23 ± 3 versus 17 ± 2 ml min(-1); both P < 0.05) among mild workloads, whereas this was not the case for moderate-intensity exercise. In protocol 2 (n = 13), subjects performed rhythmic dynamic hand-grip exercise at mild and moderate intensities in conditions of matched total work, but muscle fibre recruitment was manipulated. In this protocol, greater muscle fibre recruitment led to significantly greater FBF (152 ± 15 versus 127 ± 13 ml min(-1)) and (20 ± 2 versus 17 ± 2 ml min(-1); both P < 0.05) at mild workloads, and there was a trend for similar responses at the moderate intensity but this was not statistically significant. In both protocols, the ratio of the change in FBF to change in was similar across all exercise intensities and manipulations, and the strongest correlation among all variables was between and blood flow. Our collective data indicate that, among matched workloads, shorter contraction duration and greater muscle fibre recruitment augment FBF and during mild-intensity forearm exercise, and that muscle blood flow is more closely related to metabolic cost ( ) rather than contractile work per se during steady-state exercise in humans.

Influence of menopause status and age on integrated central and peripheral hemodynamic responses to subsystolic cuffing during submaximal exercise

PubMed Central

Gramm, Courtney; Randall, Nicholas R.; Olson, Thomas P.

2016-01-01

Although pathophysiological links between postmenopause and healthy aging remain unclear, both factors are associated with increased blood pressure and sympathetic nerve activity (SNA) in women. Activation of polymodal musculoskeletal neural afferents originating within adventia of venules modulates SNA and blood pressure control during exercise in healthy adults. We hypothesized transient subsystolic regional circulatory occlusion (RCO) during exercise sensitizes these afferents leading to augmented systemic vascular resistance (SVR)-mediated increased mean arterial pressure (MAP) in postmenopause vs. premenopause. Normotensive women in premenopause or postmenopause (n = 14 and 14; ages: 30 ± 9 and 55 ± 7 yr, respectively; P < 0.01) performed: 1) peak exercise testing and 2) fixed-load cycling at 30% peak workload (48 ± 11 and 38 ± 6 W, respectively; P < 0.01), whereby the initial 3 min were control exercise without RCO (CTL), thereafter including 2 min of bilateral-thigh RCO to 20, 40, 60, 80, or 100 mmHg (randomized), with 2 min deflation between RCO. Both MAP (17 ± 4 vs. 4 ± 4%, P = 0.02) and SVR (16 ± 8 vs. −3 ± 8%, P = 0.04) increased at 80 mmHg from CTL in postmenopause vs. premenopause, respectively. However, cardiac index was similar in postmenopause vs. premenopause at 80 mmHg from CTL (1 ± 6 vs. 7 ± 6%, respectively; P = 0.15). There was no continuous effect of aging in MAP (P = 0.12), SVR (P = 0.07), or cardiac index (P = 0.18) models. These data suggest transient locomotor subsystolic RCO sensitizes musculoskeletal afferents, which provoke increased SVR to generate augmented MAP during exercise in postmenopause. These observations provide a novel approach for understanding the age-independent variability in exercise blood pressure control across the normotensive adult pre- to postmenopause spectrum. PMID:27765745

Body temperature and cold sensation during and following exercise under temperate room conditions in cold-sensitive young trained females.

PubMed

Fujii, Naoto; Aoki-Murakami, Erii; Tsuji, Bun; Kenny, Glen P; Nagashima, Kei; Kondo, Narihiko; Nishiyasu, Takeshi

2017-11-01

We evaluated cold sensation at rest and in response to exercise-induced changes in core and skin temperatures in cold-sensitive exercise trained females. Fifty-eight trained young females were screened by a questionnaire, selecting cold-sensitive (Cold-sensitive, n  = 7) and non-cold-sensitive (Control, n  = 7) individuals. Participants rested in a room at 29.5°C for ~100 min after which ambient temperature was reduced to 23.5°C where they remained resting for 60 min. Participants then performed 30-min of moderate intensity cycling (50% peak oxygen uptake) followed by a 60-min recovery. Core and mean skin temperatures and cold sensation over the whole-body and extremities (fingers and toes) were assessed throughout. Resting core temperature was lower in the Cold-sensitive relative to Control group (36.4 ± 0.3 vs. 36.7 ± 0.2°C). Core temperature increased to similar levels at end-exercise (~37.2°C) and gradually returned to near preexercise rest levels at the end of recovery (>36.6°C). Whole-body cold sensation was greater in the Cold-sensitive relative to Control group during resting at a room temperature of 23.5°C only without a difference in mean skin temperature between groups. In contrast, cold sensation of the extremities was greater in the Cold-sensitive group prior to, during and following exercise albeit this was not paralleled by differences in mean extremity skin temperature. We show that young trained females who are sensitive to cold exhibit augmented whole-body cold sensation during rest under temperate ambient conditions. However, this response is diminished during and following exercise. In contrast, cold sensation of extremities is augmented during resting that persists during and following exercise. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Influence of menopause status and age on integrated central and peripheral hemodynamic responses to subsystolic cuffing during submaximal exercise.

PubMed

Van Iterson, Erik H; Gramm, Courtney; Randall, Nicholas R; Olson, Thomas P

2016-12-01

Although pathophysiological links between postmenopause and healthy aging remain unclear, both factors are associated with increased blood pressure and sympathetic nerve activity (SNA) in women. Activation of polymodal musculoskeletal neural afferents originating within adventia of venules modulates SNA and blood pressure control during exercise in healthy adults. We hypothesized transient subsystolic regional circulatory occlusion (RCO) during exercise sensitizes these afferents leading to augmented systemic vascular resistance (SVR)-mediated increased mean arterial pressure (MAP) in postmenopause vs. premenopause. Normotensive women in premenopause or postmenopause (n = 14 and 14; ages: 30 ± 9 and 55 ± 7 yr, respectively; P < 0.01) performed: 1) peak exercise testing and 2) fixed-load cycling at 30% peak workload (48 ± 11 and 38 ± 6 W, respectively; P < 0.01), whereby the initial 3 min were control exercise without RCO (CTL), thereafter including 2 min of bilateral-thigh RCO to 20, 40, 60, 80, or 100 mmHg (randomized), with 2 min deflation between RCO. Both MAP (17 ± 4 vs. 4 ± 4%, P = 0.02) and SVR (16 ± 8 vs. -3 ± 8%, P = 0.04) increased at 80 mmHg from CTL in postmenopause vs. premenopause, respectively. However, cardiac index was similar in postmenopause vs. premenopause at 80 mmHg from CTL (1 ± 6 vs. 7 ± 6%, respectively; P = 0.15). There was no continuous effect of aging in MAP (P = 0.12), SVR (P = 0.07), or cardiac index (P = 0.18) models. These data suggest transient locomotor subsystolic RCO sensitizes musculoskeletal afferents, which provoke increased SVR to generate augmented MAP during exercise in postmenopause. These observations provide a novel approach for understanding the age-independent variability in exercise blood pressure control across the normotensive adult pre- to postmenopause spectrum. Copyright © 2016 the American Physiological Society.

Military-specific application of nutritional supplements: a brief overview.

PubMed

Hoedebecke, Kyle; Brink, Will

2015-01-01

The Soldiers of America's military endure numerous physical and mental challenges that demand strict physical fitness regimens, extreme mental agility, and a perpetual readiness to deploy at a moment's notice. The chronicity of these stressors has the potential to dramatically reduce performance - both directly and indirectly.  Because of this risk, many Soldiers turn to nutritional supplements with hopes of optimizing performance. Increasing amounts of research have demonstrated that various supplements may enhance overall physical prowess, health, and offer quicker recovery in the face of corporal or psychological extremes. Most individuals, including many medical and nutrition professionals, possess only an elementary comprehension of nutritional supplements and their effect on Soldiers in training or combat environments. Nevertheless, a grasp of these details is required for safety and optimal benefits. Various compounds have been evaluated - to include evidence within the military setting - and found to augment endurance, increase cognitive function, decrease knee pain, or offer hearing or lung protection in the face of high-energy impulses. These efficacious outcomes may serve to augment the health and longevity of these Soldiers; however, continued research is needed for efficacy and long-term safety within specific environments.

A fingertip force prediction model for grasp patterns characterised from the chaotic behaviour of EEG.

PubMed

Roy, Rinku; Sikdar, Debdeep; Mahadevappa, Manjunatha; Kumar, C S

2018-05-19

A stable grasp is attained through appropriate hand preshaping and precise fingertip forces. Here, we have proposed a method to decode grasp patterns from motor imagery and subsequent fingertip force estimation model with a slippage avoidance strategy. We have developed a feature-based classification of electroencephalography (EEG) associated with imagination of the grasping postures. Chaotic behaviour of EEG for different grasping patterns has been utilised to capture the dynamics of associated motor activities. We have computed correlation dimension (CD) as the feature and classified with "one against one" multiclass support vector machine (SVM) to discriminate between different grasping patterns. The result of the analysis showed varying classification accuracies at different subband levels. Broad categories of grasping patterns, namely, power grasp and precision grasp, were classified at a 96.0% accuracy rate in the alpha subband. Furthermore, power grasp subtypes were classified with an accuracy of 97.2% in the upper beta subband, whereas precision grasp subtypes showed relatively lower 75.0% accuracy in the alpha subband. Following assessment of fingertip force distributions while grasping, a nonlinear autoregressive (NAR) model with proper prediction of fingertip forces was proposed for each grasp pattern. A slippage detection strategy has been incorporated with automatic recalibration of the regripping force. Intention of each grasp pattern associated with corresponding fingertip force model was virtualised in this work. This integrated system can be utilised as the control strategy for prosthetic hand in the future. The model to virtualise motor imagery based fingertip force prediction with inherent slippage correction for different grasp types ᅟ.

Effect of visual and tactile feedback on kinematic synergies in the grasping hand.

PubMed

Patel, Vrajeshri; Burns, Martin; Vinjamuri, Ramana

2016-08-01

The human hand uses a combination of feedforward and feedback mechanisms to accomplish high degree of freedom in grasp control efficiently. In this study, we used a synergy-based control model to determine the effect of sensory feedback on kinematic synergies in the grasping hand. Ten subjects performed two types of grasps: one that included feedback (real) and one without feedback (memory-guided), at two different speeds (rapid and natural). Kinematic synergies were extracted from rapid real and rapid memory-guided grasps using principal component analysis. Synergies extracted from memory-guided grasps revealed greater preservation of natural inter-finger relationships than those found in corresponding synergies extracted from real grasps. Reconstruction of natural real and natural memory-guided grasps was used to test performance and generalizability of synergies. A temporal analysis of reconstruction patterns revealed the differing contribution of individual synergies in real grasps versus memory-guided grasps. Finally, the results showed that memory-guided synergies could not reconstruct real grasps as accurately as real synergies could reconstruct memory-guided grasps. These results demonstrate how visual and tactile feedback affects a closed-loop synergy-based motor control system.

Effects of grasp compatibility on long-term memory for objects.

PubMed

Canits, Ivonne; Pecher, Diane; Zeelenberg, René

2018-01-01

Previous studies have shown action potentiation during conceptual processing of manipulable objects. In four experiments, we investigated whether these motor actions also play a role in long-term memory. Participants categorized objects that afforded either a power grasp or a precision grasp as natural or artifact by grasping cylinders with either a power grasp or a precision grasp. In all experiments, responses were faster when the affordance of the object was compatible with the type of grasp response. However, subsequent free recall and recognition memory tasks revealed no better memory for object pictures and object names for which the grasp affordance was compatible with the grasp response. The present results therefore do not support the hypothesis that motor actions play a role in long-term memory. Copyright © 2017 Elsevier B.V. All rights reserved.

Mena–GRASP65 interaction couples actin polymerization to Golgi ribbon linking

PubMed Central

Tang, Danming; Zhang, Xiaoyan; Huang, Shijiao; Yuan, Hebao; Li, Jie; Wang, Yanzhuang

2016-01-01

In mammalian cells, the Golgi reassembly stacking protein 65 (GRASP65) has been implicated in both Golgi stacking and ribbon linking by forming trans-oligomers through the N-terminal GRASP domain. Because the GRASP domain is globular and relatively small, but the gaps between stacks are large and heterogeneous, it remains puzzling how GRASP65 physically links Golgi stacks into a ribbon. To explore the possibility that other proteins may help GRASP65 in ribbon linking, we used biochemical methods and identified the actin elongation factor Mena as a novel GRASP65-binding protein. Mena is recruited onto the Golgi membranes through interaction with GRASP65. Depleting Mena or disrupting actin polymerization resulted in Golgi fragmentation. In cells, Mena and actin were required for Golgi ribbon formation after nocodazole washout; in vitro, Mena and microfilaments enhanced GRASP65 oligomerization and Golgi membrane fusion. Thus Mena interacts with GRASP65 to promote local actin polymerization, which facilitates Golgi ribbon linking. PMID:26538023

Vivaldi: visualization and validation of biomacromolecular NMR structures from the PDB.

PubMed

Hendrickx, Pieter M S; Gutmanas, Aleksandras; Kleywegt, Gerard J

2013-04-01

We describe Vivaldi (VIsualization and VALidation DIsplay; http://pdbe.org/vivaldi), a web-based service for the analysis, visualization, and validation of NMR structures in the Protein Data Bank (PDB). Vivaldi provides access to model coordinates and several types of experimental NMR data using interactive visualization tools, augmented with structural annotations and model-validation information. The service presents information about the modeled NMR ensemble, validation of experimental chemical shifts, residual dipolar couplings, distance and dihedral angle constraints, as well as validation scores based on empirical knowledge and databases. Vivaldi was designed for both expert NMR spectroscopists and casual non-expert users who wish to obtain a better grasp of the information content and quality of NMR structures in the public archive. Copyright © 2013 Wiley Periodicals, Inc.

Fast grasping of unknown objects using principal component analysis

NASA Astrophysics Data System (ADS)

Lei, Qujiang; Chen, Guangming; Wisse, Martijn

2017-09-01

Fast grasping of unknown objects has crucial impact on the efficiency of robot manipulation especially subjected to unfamiliar environments. In order to accelerate grasping speed of unknown objects, principal component analysis is utilized to direct the grasping process. In particular, a single-view partial point cloud is constructed and grasp candidates are allocated along the principal axis. Force balance optimization is employed to analyze possible graspable areas. The obtained graspable area with the minimal resultant force is the best zone for the final grasping execution. It is shown that an unknown object can be more quickly grasped provided that the component analysis principle axis is determined using single-view partial point cloud. To cope with the grasp uncertainty, robot motion is assisted to obtain a new viewpoint. Virtual exploration and experimental tests are carried out to verify this fast gasping algorithm. Both simulation and experimental tests demonstrated excellent performances based on the results of grasping a series of unknown objects. To minimize the grasping uncertainty, the merits of the robot hardware with two 3D cameras can be utilized to suffice the partial point cloud. As a result of utilizing the robot hardware, the grasping reliance is highly enhanced. Therefore, this research demonstrates practical significance for increasing grasping speed and thus increasing robot efficiency under unpredictable environments.

The role of descriptive norm within the theory of planned behavior in predicting Korean Americans' exercise behavior.

PubMed

Lee, Hyo

2011-08-01

There are few studies investigating psychosocial mechanisms in Korean Americans' exercise behavior. The present study tested the usefulness of the theory of planned behavior in predicting Korean American's exercise behavior and whether the descriptive norm (i.e., perceptions of what others do) improved the predictive validity of the theory of planned behavior. Using a retrospective design and self-report measures, web-survey responses from 198 Korean-American adults were analyzed using hierarchical regression analyses. The theory of planned behavior constructs accounted for 31% of exercise behavior and 43% of exercise intention. Intention and perceived behavioral control were significant predictors of exercise behavior. Although the descriptive norm did not augment the theory of planned behavior, all original constructs--attitude, injunctive norm (a narrow definition of subjective norm), and perceived behavioral control--statistically significantly predicted leisure-time physical activity intention. Future studies should consider random sampling, prospective design, and objective measures of physical activity.

Use of virtual reality technique for the training of motor control in the elderly. Some theoretical considerations.

PubMed

de Bruin, E D; Schoene, D; Pichierri, G; Smith, S T

2010-08-01

Virtual augmented exercise, an emerging technology that can help to promote physical activity and combine the strengths of indoor and outdoor exercise, has recently been proposed as having the potential to increase exercise behavior in older adults. By creating a strong presence in a virtual, interactive environment, distraction can be taken to greater levels while maintaining the benefits of indoor exercises which may result in a shift from negative to positive thoughts about exercise. Recent findings on young participants show that virtual reality training enhances mood, thus, increasing enjoyment and energy. For older adults virtual, interactive environments can influence postural control and fall events by stimulating the sensory cues that are responsible in maintaining balance and orientation. However, the potential of virtual reality training has yet to be explored for older adults. This manuscript describes the potential of dance pad training protocols in the elderly and reports on the theoretical rationale of combining physical game-like exercises with sensory and cognitive challenges in a virtual environment.

An instrumented object for hand exercise and assessment using a pneumatic pressure sensor

NASA Astrophysics Data System (ADS)

Mohan, A.; Tharion, G.; Kumar, R. K.; Devasahayam, S. R.

2018-05-01

Measurement of grip force is important for both exercise training and assessment of the hand during physical rehabilitation. The standard method uses a grip dynamometer which measures the force between the fingers and opposing thumb. The primary limitation of the grip dynamometer is the restriction of measurement to cylindrical grasps. Any deformation of the hand due to muscular or skeletal disease makes the grip dynamometer difficult or impossible to use. An alternative to the grip dynamometer is a sealed pneumatic object that can be gripped by the hand. Measurement of the internal pressure in the object can be related to the grip force. In this paper, we analyze such a pneumatic pressure sensing object for hand grip assessment and also describe an easy fabrication of the grip sensor. The instrumented object presented in this paper is designed to assess both the maximal voluntary grip forces and continuous grip force to monitor control of hand function during exercise under instruction from a therapist. Potential uses of such a pneumatic pressure sensing object for hand grip are in physical rehabilitation of patients following paralysing illnesses like stroke and spinal cord injury.

Forecasting: Exercises to Enhance Learning from Business Simulations

ERIC Educational Resources Information Center

Clark, Timothy S.; Kent, Brian M.

2013-01-01

Forecasting the outputs of dynamic systems develops a richer understanding of relevant inputs and their interrelationships than merely observing them ex post. Academic business simulations foster students' development of this critical competency, but learning outcomes can be significantly augmented with relatively simple, complementary exercises…

Augmented reality experimentation on oxygen gas generation from hydrogen peroxide and bleach reaction.

PubMed

Gan, Hong Seng; Tee, Nicholas Yee Kwang; Bin Mamtaz, Mohammad Raziun; Xiao, Kevin; Cheong, Brandon Huey-Ping; Liew, Oi Wah; Ng, Tuck Wah

2018-05-01

The appreciation and understanding of gas generation through processes is vital in biochemical education. In this work, an augmented reality tool is reported to depict the redox reaction between hydrogen peroxide and sodium hypochlorite solutions, two ubiquitous oxidizing agents, to create oxygen, a combustible gas. As it operates out of smartphones or tablets, students are able to conduct the exercise collaboratively, respond in a manner similar to an actual physical experiment, and able to depict the oxygen volume changes in relation to the volume of hydrogen peroxide of different concentrations used. The tool offers to help students acquire bench skills by limiting handing risks and to mitigate possible student anxiety on handling chemical materials and implements in the laboratory. The feedback received from Year 11 and 12 high school student participants in an outreach exercise indicate the overall effectiveness of this tool. © 2018 by The International Union of Biochemistry and Molecular Biology, 46(3):245-252, 2018. © 2018 The International Union of Biochemistry and Molecular Biology.

Effect of inorganic nitrate on exercise capacity in heart failure with preserved ejection fraction.

PubMed

Zamani, Payman; Rawat, Deepa; Shiva-Kumar, Prithvi; Geraci, Salvatore; Bhuva, Rushik; Konda, Prasad; Doulias, Paschalis-Thomas; Ischiropoulos, Harry; Townsend, Raymond R; Margulies, Kenneth B; Cappola, Thomas P; Poole, David C; Chirinos, Julio A

2015-01-27

Inorganic nitrate (NO3(-)), abundant in certain vegetables, is converted to nitrite by bacteria in the oral cavity. Nitrite can be converted to nitric oxide in the setting of hypoxia. We tested the hypothesis that NO3(-) supplementation improves exercise capacity in heart failure with preserved ejection fraction via specific adaptations to exercise. Seventeen subjects participated in this randomized, double-blind, crossover study comparing a single dose of NO3-rich beetroot juice (NO3(-), 12.9 mmol) with an identical nitrate-depleted placebo. Subjects performed supine-cycle maximal-effort cardiopulmonary exercise tests, with measurements of cardiac output and skeletal muscle oxygenation. We also assessed skeletal muscle oxidative function. Study end points included exercise efficiency (total work/total oxygen consumed), peak VO2, total work performed, vasodilatory reserve, forearm mitochondrial oxidative function, and augmentation index (a marker of arterial wave reflections, measured via radial arterial tonometry). Supplementation increased plasma nitric oxide metabolites (median, 326 versus 10 μmol/L; P=0.0003), peak VO2 (12.6±3.7 versus 11.6±3.1 mL O2·min(-1)·kg(-1); P=0.005), and total work performed (55.6±35.3 versus 49.2±28.9 kJ; P=0.04). However, efficiency was unchanged. NO3(-) led to greater reductions in systemic vascular resistance (-42.4±16.6% versus -31.8±20.3%; P=0.03) and increases in cardiac output (121.2±59.9% versus 88.7±53.3%; P=0.006) with exercise. NO3(-) reduced aortic augmentation index (132.2±16.7% versus 141.4±21.9%; P=0.03) and tended to improve mitochondrial oxidative function. NO3(-) increased exercise capacity in heart failure with preserved ejection fraction by targeting peripheral abnormalities. Efficiency did not change as a result of parallel increases in total work and VO2. NO3(-) increased exercise vasodilatory and cardiac output reserves. NO3(-) also reduced arterial wave reflections, which are linked to left ventricular diastolic dysfunction and remodeling. www.clinicaltrials.gov. Unique identifier: NCT01919177. © 2014 American Heart Association, Inc.

Isoform-specific tethering links the Golgi ribbon to maintain compartmentalization

PubMed Central

Jarvela, Timothy; Linstedt, Adam D.

2014-01-01

Homotypic membrane tethering by the Golgi reassembly and stacking proteins (GRASPs) is required for the lateral linkage of mammalian Golgi ministacks into a ribbon-like membrane network. Although GRASP65 and GRASP55 are specifically localized to cis and medial/trans cisternae, respectively, it is unknown whether each GRASP mediates cisternae-specific tethering and whether such specificity is necessary for Golgi compartmentalization. Here each GRASP was tagged with KillerRed (KR), expressed in HeLa cells, and inhibited by 1-min exposure to light. Significantly, inactivation of either GRASP unlinked the Golgi ribbon, and the immediate effect of GRASP65-KR inactivation was a loss of cis- rather than trans-Golgi integrity, whereas inactivation of GRASP55-KR first affected the trans- and not the cis-Golgi. Thus each GRASP appears to play a direct and cisternae-specific role in linking ministacks into a continuous membrane network. To test the consequence of loss of cisternae-specific tethering, we generated Golgi membranes with a single GRASP on all cisternae. Remarkably, the membranes exhibited the full connectivity of wild-type Golgi ribbons but were decompartmentalized and defective in glycan processing. Thus the GRASP isoforms specifically link analogous cisternae to ensure Golgi compartmentalization and proper processing. PMID:24227884

Distinct neural patterns enable grasp types decoding in monkey dorsal premotor cortex.

PubMed

Hao, Yaoyao; Zhang, Qiaosheng; Controzzi, Marco; Cipriani, Christian; Li, Yue; Li, Juncheng; Zhang, Shaomin; Wang, Yiwen; Chen, Weidong; Chiara Carrozza, Maria; Zheng, Xiaoxiang

2014-12-01

Recent studies have shown that dorsal premotor cortex (PMd), a cortical area in the dorsomedial grasp pathway, is involved in grasp movements. However, the neural ensemble firing property of PMd during grasp movements and the extent to which it can be used for grasp decoding are still unclear. To address these issues, we used multielectrode arrays to record both spike and local field potential (LFP) signals in PMd in macaque monkeys performing reaching and grasping of one of four differently shaped objects. Single and population neuronal activity showed distinct patterns during execution of different grip types. Cluster analysis of neural ensemble signals indicated that the grasp related patterns emerged soon (200-300 ms) after the go cue signal, and faded away during the hold period. The timing and duration of the patterns varied depending on the behaviors of individual monkey. Application of support vector machine model to stable activity patterns revealed classification accuracies of 94% and 89% for each of the two monkeys, indicating a robust, decodable grasp pattern encoded in the PMd. Grasp decoding using LFPs, especially the high-frequency bands, also produced high decoding accuracies. This study is the first to specify the neuronal population encoding of grasp during the time course of grasp. We demonstrate high grasp decoding performance in PMd. These findings, combined with previous evidence for reach related modulation studies, suggest that PMd may play an important role in generation and maintenance of grasp action and may be a suitable locus for brain-machine interface applications.

Kinematics and force analysis of a robot hand based on an artificial biological control scheme

NASA Astrophysics Data System (ADS)

Kim, Man Guen

An artificial biological control scheme (ABCS) is used to study the kinematics and statics of a multifingered hand with a view to developing an efficient control scheme for grasping. The ABCS is based on observation of human grasping, intuitively taking it as the optimum model for robotic grasping. A final chapter proposes several grasping measures to be applied to the design and control of a robot hand. The ABCS leads to the definition of two modes of the grasping action: natural grasping (NG), which is the human motion to grasp the object without any special task command, and forced grasping (FG), which is the motion with a specific task. The grasping direction line (GDL) is defined to determine the position and orientation of the object in the hand. The kinematic model of a redundant robot arm and hand is developed by reconstructing the human upper extremity and using anthropometric measurement data. The inverse kinematic analyses of various types of precision and power grasping are studied by replacing the three-link with one virtual link and using the GDL. The static force analysis for grasping with fingertips is studied by applying the ABCS. A measure of grasping stability, that maintains the positions of contacts as well as the configurations of the redundant fingers, is derived. The grasping stability measure (GSM), a measure of how well the hand maintains grasping under the existence of external disturbance, is derived by the torque vector of the hand calculated from the external force applied to the object. The grasping manipulability measure (GMM), a measure of how well the hand manipulates the object for the task, is derived by the joint velocity vector of the hand calculated from the object velocity. The grasping performance measure (GPM) is defined by the sum of the directional components of the GSM and the GMM. Finally, a planar redundant hand with two fingers is examined in order to study the various postures of the hand performing pinch grasping by applying the GSM and the GMM.

Effects of pomegranate extract on blood flow and running time to exhaustion.

PubMed

Trexler, Eric T; Smith-Ryan, Abbie E; Melvin, Malia N; Roelofs, Erica J; Wingfield, Hailee L

2014-09-01

Recent research has shown that dietary nitrate has favorable effects on blood flow and exercise performance. The purpose of this randomized, double-blind, placebo-controlled crossover study was to investigate the acute effects of pomegranate extract on blood flow, vessel diameter, and exercise performance in active individuals. Nineteen men and women (mean ± SD: age, 22.2 ± 2.2 years; height, 174.8 ± 10.7 cm; body mass, 71.9 ± 13.5 kg) were randomly assigned to a placebo (PL) or pomegranate extract (PE) group. Participants performed a maximal oxygen consumption treadmill test to determine peak velocity (PV). Participants returned after 24-48 h and ingested either PL or PE. Brachial artery blood flow was assessed using ultrasound at baseline and 30 min post-ingestion (30minPI). Three treadmill runs to exhaustion were performed at 90%, 100%, and 110% PV. Blood flow was assessed immediately after each exercise bout and 30 min postexercise (30minPEx). After a 7-10 day washout, participants repeated the same procedures, ingesting the opposite supplement. Separate repeated measures ANOVAs were performed for blood flow, vessel diameter, and time to exhaustion (TTE). Blood flow was significantly augmented (p = 0.033) 30minPI with PE in comparison with PL. Vessel diameter was significantly larger (p = 0.036) 30minPEx with PE. Ingestion of PE was found to significantly augment TTE at 90% (p = 0.009) and 100% PV (p = 0.027). Acute ingestion of PE 30 min before exercise may enhance vessel diameter and blood flow and delay fatigue during exercise. Results of the current study indicate that PE is ergogenic for intermittent running, eliciting beneficial effects on blood flow.

Effect of orofacial exercises on oral aperture in adults with systemic sclerosis

PubMed Central

Yuen, Hon K.; Marlow, Nicole M.; Reed, Susan G.; Summerlin, Lisa M.; Leite, Renata S.; Mahoney, Samantha; Silver, Richard M.

2012-01-01

Purpose To examine the effect of a home orofacial exercise program on increasing oral aperture among adults with systemic sclerosis (SSc). Method Forty-eight adults with SSc were assigned randomly to the multi-faceted oral health intervention or usual dental care control group. Participants with an oral aperture of < 40 mm in the intervention group received an orofacial exercise program, which included daily manual mouth-stretching and oral augmentation exercises twice a day with a total of 6 minutes for 6 months. The outcome measure was oral aperture which was measured at baseline, 3-months, and 6-months intervals. Results A significantly larger increase in oral aperture for participants received the orofacial exercise program was found when compared to those in the usual care at 3 months (P=0.01), but not at 6 months evaluation. Participants’ adherence rate to the exercise program was low (48.9%). Conclusions The orofacial exercise program intervention for adults with SSc and microstomia did not show significant improvement at 6 months. In addition to the low exercise adherence rate, insufficient frequencies, repetitions, and durations of the orofacial exercises may contribute to these results. PMID:21951278

Modular mechatronic system for stationary bicycles interfaced with virtual environment for rehabilitation

PubMed Central

2014-01-01

Background Cycling has been used in the rehabilitation of individuals with both chronic and post-surgical conditions. Among the challenges with implementing bicycling for rehabilitation is the recruitment of both extremities, in particular when one is weaker or less coordinated. Feedback embedded in virtual reality (VR) augmented cycling may serve to address the requirement for efficacious cycling; specifically recruitment of both extremities and exercising at a high intensity. Methods In this paper a mechatronic rehabilitation bicycling system with an interactive virtual environment, called Virtual Reality Augmented Cycling Kit (VRACK), is presented. Novel hardware components embedded with sensors were implemented on a stationary exercise bicycle to monitor physiological and biomechanical parameters of participants while immersing them in an augmented reality simulation providing the user with visual, auditory and haptic feedback. This modular and adaptable system attaches to commercially-available stationary bicycle systems and interfaces with a personal computer for simulation and data acquisition processes. The complete bicycle system includes: a) handle bars based on hydraulic pressure sensors; b) pedals that monitor pedal kinematics with an inertial measurement unit (IMU) and forces on the pedals while providing vibratory feedback; c) off the shelf electronics to monitor heart rate and d) customized software for rehabilitation. Bench testing for the handle and pedal systems is presented for calibration of the sensors detecting force and angle. Results The modular mechatronic kit for exercise bicycles was tested in bench testing and human tests. Bench tests performed on the sensorized handle bars and the instrumented pedals validated the measurement accuracy of these components. Rider tests with the VRACK system focused on the pedal system and successfully monitored kinetic and kinematic parameters of the rider’s lower extremities. Conclusions The VRACK system, a virtual reality mechatronic bicycle rehabilitation modular system was designed to convert most bicycles in virtual reality (VR) cycles. Preliminary testing of the augmented reality bicycle system was successful in demonstrating that a modular mechatronic kit can monitor and record kinetic and kinematic parameters of several riders. PMID:24902780

Exaggerated haemodynamic and neural responses to involuntary contractions induced by whole-body vibration in normotensive obese versus lean women.

PubMed

Dipla, Konstantina; Kousoula, Dimitra; Zafeiridis, Andreas; Karatrantou, Konstantina; Nikolaidis, Michalis G; Kyparos, Antonios; Gerodimos, Vassilis; Vrabas, Ioannis S

2016-06-01

What is the central question of this study? In obesity, the exaggerated blood pressure response to voluntary exercise is linked to hypertension, yet the mechanisms are not fully elucidated. We examined whether involuntary contractions elicit greater haemodynamic responses and altered neural control of blood pressure in normotensive obese versus lean women. What is the main finding and its importance? During involuntary contractions induced by whole-body vibration, there were augmented blood pressure and spontaneous baroreflex responses in obese compared with lean women. This finding is suggestive of an overactive mechanoreflex in the exercise-induced hypertensive response in obesity. Passive contractions did not elicit differential heart rate responses in obese compared with lean women, implying other mechanisms for the blunted heart rate response reported during voluntary exercise in obesity. In obesity, the exaggerated blood pressure (BP) response to exercise is linked to hypertension, yet the mechanisms are not fully elucidated. In this study, we examined whether involuntary mechanical oscillations, induced by whole-body vibration (WBV), elicit greater haemodynamic responses and altered neural control of BP in obese versus lean women. Twenty-two normotensive, premenopausal women (12 lean and 10 obese) randomly underwent a passive WBV (25 Hz) and a control protocol (similar posture without WVB). Beat-by-beat BP, heart rate, stroke volume, systemic vascular resistance, cardiac output, parasympathetic output (evaluated by heart rate variability) and spontaneous baroreceptor sensitivity (sBRS) were assessed. We found that during WBV, obese women exhibited an augmented systolic BP response compared with lean women that was correlated with body fat percentage (r = 0.77; P < 0.05). The exaggerated BP rise was driven mainly by the greater increase in cardiac output index in obese versus lean women, associated with a greater stroke volume index in obese women. Involuntary contractions did not elicit a differential magnitude of responses in heart rate, heart rate variability indices and systemic vascular resistance in obese versus lean women; however, they did result in greater sBRS responses (P < 0.05) in obese women. In conclusion, involuntary contractions elicited an augmented BP and sBRS response in normotensive obese versus lean women. The greater elevations in circulatory haemodynamics in obese women are suggestive of an overactive mechanoreflex in the exercise-induced hypertensive response in obesity. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Short-Term Modulation of the Ventilatory Response to Exercise is Preserved in Obstructive Sleep Apnea

PubMed Central

Bernhardt, Vipa; Mitchell, Gordon S.; Lee, Won Y.; Babb, Tony G.

2016-01-01

Background The ventilatory response to exercise can be transiently adjusted in response to environmentally (e.g., breathing apparatus) or physiologically altered conditions (e.g., respiratory disease), maintaining constant relative arterial PCO2 regulation from rest to exercise (Mitchell and Babb, 2006); this augmentation is called short-term modulation (STM) of the exercise ventilatory response. Obesity and/or obstructive sleep apnea could affect the exercise ventilatory response and the capacity for STM due to chronically increased mechanical and/or ventilatory loads on the respiratory system, and/or recurrent (chronic) intermittent hypoxia experienced during sleep. We hypothesized that: 1) the exercise ventilatory response is augmented in obese OSA patients compared with obese non-OSA adults, and 2) the capacity for STM with added dead space is diminished in obese OSA patients. Methods Nine obese adults with OSA (age: 39 ± 6 yr, BMI: 40 ± 5 kg/m2, AHI: 25 ± 24 events/hr [range 6–73], mean ± SD) and 8 obese adults without OSA (age: 38 ± 10 yr, BMI: 37 ± 6 kg/m2, AHI: 1 ± 2) completed three, 20-min bouts of constant-load submaximal cycling exercise (8 min rest, 6 min at 10 and 30 W) with or without added external dead space (200 or 400 ml; 20 min rest between bouts). Steady-state measurements were made of ventilation (V̇E), oxygen consumption (V̇O2), carbon dioxide production (V̇CO2), and end-tidal PCO2 (PETCO2). The exercise ventilatory response was defined as the slope of the V̇E-V̇CO2 relationship (ΔV̇E/ΔV̇CO2). Results In control (i.e. no added dead space), the exercise ventilatory response was not significantly different between non-OSA and OSA groups (ΔV̇E/ΔV̇CO2 slope: 30.5 ± 4.2 vs 30.5 ± 3.8, p > 0.05); PETCO2 regulation from rest to exercise did not differ between groups (p > 0.05). In trials with added external dead space, ΔV̇E/ΔV̇CO2 increased with increased dead space (p < 0.05) and the PETCO2 change from rest to exercise remained small (<2 mmHg) in both groups, demonstrating STM. There were no significant differences between groups. Conclusions Contrary to our hypotheses: 1) the exercise ventilatory response is not increased in obese OSA patients compared with obese non-OSA adults, and 2) the capacity for STM with added dead space is preserved in obese OSA and non-OSA adults. PMID:27840272

Neural blockade during exercise augments central command's contribution to carotid baroreflex resetting

NASA Technical Reports Server (NTRS)

Querry, R. G.; Smith, S. A.; Stromstad, M.; Ide, K.; Raven, P. B.; Secher, N. H.

2001-01-01

This investigation was designed to determine central command's role on carotid baroreflex (CBR) resetting during exercise. Nine volunteer subjects performed static and rhythmic handgrip exercise at 30 and 40% maximal voluntary contraction (MVC), respectively, before and after partial axillary neural blockade. Stimulus-response curves were developed using the neck pressure-neck suction technique and a rapid pulse train protocol (+40 to -80 Torr). Regional anesthesia resulted in a significant reduction in MVC. Heart rate (HR) and ratings of perceived exertion (RPE) were used as indexes of central command and were elevated during exercise at control force intensity after induced muscle weakness. The CBR function curves were reset vertically with a minimal lateral shift during control exercise and exhibited a further parallel resetting during exercise with neural blockade. The operating point was progressively reset to coincide with the centering point of the CBR curve. These data suggest that central command was a primary mechanism in the resetting of the CBR during exercise. However, it appeared that central command modulated the carotid-cardiac reflex proportionately more than the carotid-vasomotor reflex.

Sensor fusion and augmented reality with the SAFIRE system

NASA Astrophysics Data System (ADS)

Saponaro, Philip; Treible, Wayne; Phelan, Brian; Sherbondy, Kelly; Kambhamettu, Chandra

2018-04-01

The Spectrally Agile Frequency-Incrementing Reconfigurable (SAFIRE) mobile radar system was developed and exercised at an arid U.S. test site. The system can detect hidden target using radar, a global positioning system (GPS), dual stereo color cameras, and dual stereo thermal cameras. An Augmented Reality (AR) software interface allows the user to see a single fused video stream containing the SAR, color, and thermal imagery. The stereo sensors allow the AR system to display both fused 2D imagery and 3D metric reconstructions, where the user can "fly" around the 3D model and switch between the modalities.

Blended shared control utilizing online identification : Regulating grasping forces of a surrogate surgical grasper.

PubMed

Stephens, Trevor K; Kong, Nathan J; Dockter, Rodney L; O'Neill, John J; Sweet, Robert M; Kowalewski, Timothy M

2018-06-01

Surgical robots are increasingly common, yet routine tasks such as tissue grasping remain potentially harmful with high occurrences of tissue crush injury due to the lack of force feedback from the grasper. This work aims to investigate whether a blended shared control framework which utilizes real-time identification of the object being grasped as part of the feedback may help address the prevalence of tissue crush injury in robotic surgeries. This work tests the proposed shared control framework and tissue identification algorithm on a custom surrogate surgical robotic grasping setup. This scheme utilizes identification of the object being grasped as part of the feedback to regulate to a desired force. The blended shared control is arbitrated between human and an implicit force controller based on a computed confidence in the identification of the grasped object. The online identification is performed using least squares based on a nonlinear tissue model. Testing was performed on five silicone tissue surrogates. Twenty grasps were conducted, with half of the grasps performed under manual control and half of the grasps performed with the proposed blended shared control, to test the efficacy of the control scheme. The identification method resulted in an average of 95% accuracy across all time samples of all tissue grasps using a full leave-grasp-out cross-validation. There was an average convergence time of [Formula: see text] ms across all training grasps for all tissue surrogates. Additionally, there was a reduction in peak forces induced during grasping for all tissue surrogates when applying blended shared control online. The blended shared control using online identification more successfully regulated grasping forces to the desired target force when compared with manual control. The preliminary work on this surrogate setup for surgical grasping merits further investigation on real surgical tools and with real human tissues.

Distinct neural patterns enable grasp types decoding in monkey dorsal premotor cortex

NASA Astrophysics Data System (ADS)

Hao, Yaoyao; Zhang, Qiaosheng; Controzzi, Marco; Cipriani, Christian; Li, Yue; Li, Juncheng; Zhang, Shaomin; Wang, Yiwen; Chen, Weidong; Chiara Carrozza, Maria; Zheng, Xiaoxiang

2014-12-01

Objective. Recent studies have shown that dorsal premotor cortex (PMd), a cortical area in the dorsomedial grasp pathway, is involved in grasp movements. However, the neural ensemble firing property of PMd during grasp movements and the extent to which it can be used for grasp decoding are still unclear. Approach. To address these issues, we used multielectrode arrays to record both spike and local field potential (LFP) signals in PMd in macaque monkeys performing reaching and grasping of one of four differently shaped objects. Main results. Single and population neuronal activity showed distinct patterns during execution of different grip types. Cluster analysis of neural ensemble signals indicated that the grasp related patterns emerged soon (200-300 ms) after the go cue signal, and faded away during the hold period. The timing and duration of the patterns varied depending on the behaviors of individual monkey. Application of support vector machine model to stable activity patterns revealed classification accuracies of 94% and 89% for each of the two monkeys, indicating a robust, decodable grasp pattern encoded in the PMd. Grasp decoding using LFPs, especially the high-frequency bands, also produced high decoding accuracies. Significance. This study is the first to specify the neuronal population encoding of grasp during the time course of grasp. We demonstrate high grasp decoding performance in PMd. These findings, combined with previous evidence for reach related modulation studies, suggest that PMd may play an important role in generation and maintenance of grasp action and may be a suitable locus for brain-machine interface applications.

Vibrotactile grasping force and hand aperture feedback for myoelectric forearm prosthesis users.

PubMed

Witteveen, Heidi J B; Rietman, Hans S; Veltink, Peter H

2015-06-01

User feedback about grasping force and hand aperture is very important in object handling with myoelectric forearm prostheses but is lacking in current prostheses. Vibrotactile feedback increases the performance of healthy subjects in virtual grasping tasks, but no extensive validation on potential users has been performed. Investigate the performance of upper-limb loss subjects in grasping tasks with vibrotactile stimulation, providing hand aperture, and grasping force feedback. Cross-over trial. A total of 10 subjects with upper-limb loss performed virtual grasping tasks while perceiving vibrotactile feedback. Hand aperture feedback was provided through an array of coin motors and grasping force feedback through a single miniature stimulator or an array of coin motors. Objects with varying sizes and weights had to be grasped by a virtual hand. Percentages correctly applied hand apertures and correct grasping force levels were all higher for the vibrotactile feedback condition compared to the no-feedback condition. With visual feedback, the results were always better compared to the vibrotactile feedback condition. Task durations were comparable for all feedback conditions. Vibrotactile grasping force and hand aperture feedback improves grasping performance of subjects with upper-limb loss. However, it should be investigated whether this is of additional value in daily-life tasks. This study is a first step toward the implementation of sensory vibrotactile feedback for users of myoelectric forearm prostheses. Grasping force feedback is crucial for optimal object handling, and hand aperture feedback is essential for reduction of required visual attention. Grasping performance with feedback is evaluated for the potential users. © The International Society for Prosthetics and Orthotics 2014.

LOW-LEVEL CARBON MONOXIDE EXPOSURE AND WORK CAPACITY AT 1600 METERS

EPA Science Inventory

At sea level, low-level carbon monoxide (CO) exposure impairs exercise performance. To determine if altitude residence at 1600 m augments this CO effect, two studies of graded treadmill work capacity were done. The Initial Study investigated nine, non-smoking male subjects breath...

Force feedback requirements for efficient laparoscopic grasp control.

PubMed

Westebring-van der Putten, Eleonora P; van den Dobbelsteen, John J; Goossens, Richard H M; Jakimowicz, Jack J; Dankelman, Jenny

2009-09-01

During laparoscopic grasping, tissue damage may occur due to use of excessive grasp forces and tissue slippage, whereas in barehanded grasping, humans control their grasp to prevent slippage and use of excessive force (safe grasp). This study investigates the differences in grasp control during barehanded and laparoscopic lifts. Ten novices performed lifts in order to compare pinch forces under four conditions: barehanded; using tweezers; a low-efficient grasper; and a high-efficient grasper. Results showed that participants increased their pinch force significantly later during a barehanded lift (at a pull-force level of 2.63 N) than when lifting laparoscopically (from pull-force levels of 0.77 to 1.08 N). In barehanded lifts all participants could accomplish a safe grasp, whereas in laparoscopic lifts excessive force (up to 7.9 N) and slippage (up to 38% of the trials) occurred frequently. For novices, it can be concluded that force feedback (additional to the hand-tool interface), as in skin-tissue contact, is a prerequisite to maintain a safe grasp. Much is known about grasp control during barehanded object manipulation, especially the control of pinch forces to changing loading, whereas little is known about force perception and grasp control during tool usage. This knowledge is a prerequisite for the ergonomic design of tools that are used to manipulate objects.

It’s Out of My Hands! Grasping Capacity May Not Influence Perceived Object Size

PubMed Central

2017-01-01

Linkenauger, Witt, and Proffitt (2011) found that the perceived size of graspable objects was scaled by perceived grasping capacity. However, it is possible that this effect occurred because object size was estimated on the same trial as grasping capacity. This may have led to a conflation of estimates of perceived action capacity and spatial properties. In 5 experiments, we tested Linkenauger et al.’s claim that right-handed observers overestimate the grasping capacity of their right hand relative to their left hand, and that this, in turn, leads them to underestimate the size of objects to-be-grasped in their right hand relative to their left hand. We replicated the finding that right handers overestimate the size and grasping capacity of their right hand relative to their left hand. However, when estimates of object size and grasping capacity were made in separate tasks, objects grasped in the right hand were not underestimated relative to those grasped in the left hand. Further, when grasping capacity was physically restricted, observers appropriately recalibrated their perception of their maximum grasp but estimates of object size were unaffected. Our results suggest that changes in action capacity may not influence perceived object size if sources of conflation are controlled for. PMID:28191987

Manipulation Capabilities with Simple Hands

DTIC Science & Technology

2010-01-01

allowing it to interpret online kinesthetic data, addressing two objectives: • Grasp classification: Distinguish between successful and unsuccessful...determining the grasp outcome before the grasping process is complete, by using the entire time series or kinesthetic signature of the grasping process. As...the grasp proceeds and additional kinesthetic data accumulates, the confidence also increases. In some cases Manipulation Capabilities with Simple Hands

Learning Grasp Context Distinctions that Generalize

NASA Technical Reports Server (NTRS)

Platt, Robert; Grupen, Roderic A.; Fagg, Andrew H.

2006-01-01

Control-based approaches to grasp synthesis create grasping behavior by sequencing and combining control primitives. In the absence of any other structure, these approaches must evaluate a large number of feasible control sequences as a function of object shape, object pose, and task. This work explores a new approach to grasp synthesis that limits consideration to variations on a generalized localize-reach-grasp control policy. A new learning algorithm, known as schema structured learning, is used to learn which instantiations of the generalized policy are most likely to lead to a successful grasp in different problem contexts. Two experiments are described where Dexter, a bimanual upper torso, learns to select an appropriate grasp strategy as a function of object eccentricity and orientation. In addition, it is shown that grasp skills learned in this way can generalize to new objects. Results are presented showing that after learning how to grasp a small, representative set of objects, the robot's performance quantitatively improves for similar objects that it has not experienced before.

The continuous end-state comfort effect: weighted integration of multiple biases.

PubMed

Herbort, Oliver; Butz, Martin V

2012-05-01

The grasp orientation when grasping an object is frequently aligned in anticipation of the intended rotation of the object (end-state comfort effect). We analyzed grasp orientation selection in a continuous task to determine the mechanisms underlying the end-state comfort effect. Participants had to grasp a box by a circular handle-which allowed for arbitrary grasp orientations-and then had to rotate the box by various angles. Experiments 1 and 2 revealed both that the rotation's direction considerably determined grasp orientations and that end-postures varied considerably. Experiments 3 and 4 further showed that visual stimuli and initial arm postures biased grasp orientations if the intended rotation could be easily achieved. The data show that end-state comfort but also other factors determine grasp orientation selection. A simple mechanism that integrates multiple weighted biases can account for the data.

Inverting the planning gradient: adjustment of grasps to late segments of multi-step object manipulations.

PubMed

Mathew, Hanna; Kunde, Wilfried; Herbort, Oliver

2017-05-01

When someone grasps an object, the grasp depends on the intended object manipulation and usually facilitates it. If several object manipulation steps are planned, the first step has been reported to primarily determine the grasp selection. We address whether the grasp can be aligned to the second step, if the second step's requirements exceed those of the first step. Participants grasped and rotated a dial first by a small extent and then by various extents in the opposite direction, without releasing the dial. On average, when the requirements of the first and the second step were similar, participants mostly aligned the grasp to the first step. When the requirements of the second step were considerably higher, participants aligned the grasp to the second step, even though the first step still had a considerable impact. Participants employed two different strategies. One subgroup initially aligned the grasp to the first step and then ceased adjusting the grasp to either step. Another group also initially aligned the grasp to the first step and then switched to aligning it primarily to the second step. The data suggest that participants are more likely to switch to the latter strategy when they experienced more awkward arm postures. In summary, grasp selections for multi-step object manipulations can be aligned to the second object manipulation step, if the requirements of this step clearly exceed those of the first step and if participants have some experience with the task.

Closed-loop control of grasping with a myoelectric hand prosthesis: which are the relevant feedback variables for force control?

PubMed

Ninu, Andrei; Dosen, Strahinja; Muceli, Silvia; Rattay, Frank; Dietl, Hans; Farina, Dario

2014-09-01

In closed-loop control of grasping by hand prostheses, the feedback information sent to the user is usually the actual controlled variable, i.e., the grasp force. Although this choice is intuitive and logical, the force production is only the last step in the process of grasping. Therefore, this study evaluated the performance in controlling grasp strength using a hand prosthesis operated through a complete grasping sequence while varying the feedback variables (e.g., closing velocity, grasping force), which were provided to the user visually or through vibrotactile stimulation. The experiments were conducted on 13 volunteers who controlled the Otto Bock Sensor Hand Speed prosthesis. Results showed that vibrotactile patterns were able to replace the visual feedback. Interestingly, the experiments demonstrated that direct force feedback was not essential for the control of grasping force. The subjects were indeed able to control the grip strength, predictively, by estimating the grasping force from the prosthesis velocity of closing. Therefore, grasping without explicit force feedback is not completely blind, contrary to what is usually assumed. In our study we analyzed grasping with a specific prosthetic device, but the outcomes are also applicable for other devices, with one or more degrees-of-freedom. The necessary condition is that the electromyography (EMG) signal directly and proportionally controls the velocity/grasp force of the hand, which is a common approach among EMG controlled prosthetic devices. The results provide important indications on the design of closed-loop EMG controlled prosthetic systems.

Poor shape perception is the reason reaches-to-grasp are visually guided online.

PubMed

Lee, Young-Lim; Crabtree, Charles E; Norman, J Farley; Bingham, Geoffrey P

2008-08-01

Both judgment studies and studies of feedforward reaching have shown that the visual perception of object distance, size, and shape are inaccurate. However, feedback has been shown to calibrate feedfoward reaches-to-grasp to make them accurate with respect to object distance and size. We now investigate whether shape perception (in particular, the aspect ratio of object depth to width) can be calibrated in the context of reaches-to-grasp. We used cylindrical objects with elliptical cross-sections of varying eccentricity. Our participants reached to grasp the width or the depth of these objects with the index finger and thumb. The maximum grasp aperture and the terminal grasp aperture were used to evaluate perception. Both occur before the hand has contacted an object. In Experiments 1 and 2, we investigated whether perceived shape is recalibrated by distorted haptic feedback. Although somewhat equivocal, the results suggest that it is not. In Experiment 3, we tested the accuracy of feedforward grasping with respect to shape with haptic feedback to allow calibration. Grasping was inaccurate in ways comparable to findings in shape perception judgment studies. In Experiment 4, we hypothesized that online guidance is needed for accurate grasping. Participants reached to grasp either with or without vision of the hand. The result was that the former was accurate, whereas the latter was not. We conclude that shape perception is not calibrated by feedback from reaches-to-grasp and that online visual guidance is required for accurate grasping because shape perception is poor.

Exercise as an anabolic intervention in patients with end-stage renal disease.

PubMed

Ikizler, T Alp

2011-01-01

Muscle wasting and accompanying structural derangements leading to abnormalities in muscle function, exercise performance, and physical activity are common in patients with end-stage renal disease. Therefore, several studies have been performed examining the effects of exercise in this particular patient population. Most of the studies have assessed the effects of cardiopulmonary fitness training, whereas a few have examined the role of resistance (i.e., strength) training. Despite the proven efficacy of resistance exercise as an anabolic intervention in the otherwise healthy elderly population and certain chronic disease states, recent studies in patients on maintenance hemodialysis have not been encouraging in terms of long-term improvements in markers of muscle mass. Preliminary studies indicated that a combination of simultaneous exercise and nutritional supplementation could augment the anabolic effects of exercise, at least in the acute setting. However, a recent randomized clinical trial failed to show further benefits of additional resistance exercise on long-term somatic protein accretion above and beyond nutritional supplementation alone. Further research is necessary to both understand the observed lack of obvious benefits and strategies to improve the exercise regimens in patients with end-stage renal disease. Published by Elsevier Inc.

Detecting Symptoms of Low Performance Using Production Rules

ERIC Educational Resources Information Center

Bravo, Javier; Ortigosa, Alvaro

2009-01-01

E-Learning systems offer students innovative and attractive ways of learning through augmentation or substitution of traditional lectures and exercises with online learning material. Such material can be accessed at any time from anywhere using different devices, and can be personalized according to the individual student's needs, goals and…

Role of α-adrenergic vasoconstriction in regulating skeletal muscle blood flow and vascular conductance during forearm exercise in ageing humans

PubMed Central

Richards, Jennifer C; Luckasen, Gary J; Larson, Dennis G; Dinenno, Frank A

2014-01-01

In healthy humans, ageing is typically associated with reduced skeletal muscle blood flow and vascular conductance during exercise. Further, there is a marked increase in resting sympathetic nervous system (SNS) activity with age, yet whether augmented SNS-mediated α-adrenergic vasoconstriction contributes to the age-associated impairment in exercising muscle blood flow and vascular tone in humans is unknown. We tested the hypothesis that SNS-mediated vasoconstriction is greater in older than young adults and limits muscle (forearm) blood flow (FBF) during graded handgrip exercise (5, 15, 25% maximal voluntary contraction (MVC)). FBF was measured (Doppler ultrasound) and forearm vascular conductance (FVC) was calculated in 11 young (21 ± 1 years) and 12 older (62 ± 2 years) adults in control conditions and during combined local α- and β-adrenoreceptor blockade via intra-arterial infusions of phentolamine and propranolol, respectively. Under control conditions, older adults exhibited significantly lower FBF and FVC at 15% MVC exercise (22.6 ± 1.3 vs. 29 ± 3.3 ml min−1 100 g forearm fat-free mass (FFM)−1 and 21.7 ± 1.2 vs. 33.6 ± 4.0 ml min−1 100 g FFM−1 100 mmHg−1; P < 0.05) and 25% MVC exercise (37.4 ± 1.4 vs. 46.0 ± 4.9 ml min−1 100 g FFM−1 and 33.7 ± 1.4 vs. 49.0 ± 5.7 ml min−1 100 g FFM−1 100 mmHg−1; P < 0.05), whereas there was no age group difference at 5% MVC exercise. Local adrenoreceptor blockade increased FBF and FVC at rest and during exercise in both groups, although the increase in FBF and FVC from rest to steady-state exercise was similar in young and older adults across exercise intensities, and thus the age-associated impairment in FBF and FVC persisted. Our data indicate that during graded intensity handgrip exercise, the reduced FVC and subsequently lower skeletal muscle blood flow in older healthy adults is not due to augmented sympathetic vasoconstriction, but rather due to impairments in local signalling or structural limitations in the peripheral vasculature with advancing age. PMID:25194040

Force coordination in static manipulation tasks performed using standard and non-standard grasping techniques.

PubMed

de Freitas, Paulo B; Jaric, Slobodan

2009-04-01

We evaluated coordination of the hand grip force (GF; normal component of the force acting at the hand-object contact area) and load force (LF; the tangential component) in a variety of grasping techniques and two LF directions. Thirteen participants exerted a continuous sinusoidal LF pattern against externally fixed handles applying both standard (i.e., using either the tips of the digits or the palms; the precision and palm grasps, respectively) and non-standard grasping techniques (using wrists and the dorsal finger areas; the wrist and fist grasp). We hypothesized (1) that the non-standard grasping techniques would provide deteriorated indices of force coordination when compared with the standard ones, and (2) that the nervous system would be able to adjust GF to the differences in friction coefficients of various skin areas used for grasping. However, most of the indices of force coordination remained similar across the tested grasping techniques, while the GF adjustments for the differences in friction coefficients (highest in the palm and the lowest in the fist and wrist grasp) provided inconclusive results. As hypothesized, GF relative to the skin friction was lowest in the precision grasp, but highest in the palm grasp. Therefore, we conclude that (1) the elaborate coordination of GF and LF consistently seen across the standard grasping techniques could be generalized to the non-standard ones, while (2) the ability to adjust GF using the same grasping technique to the differences in friction of various objects cannot be fully generalized to the GF adjustment when different grasps (i.e., hand segments) are used to manipulate the same object. Due to the importance of the studied phenomena for understanding both the functional and neural control aspects of manipulation, future studies should extend the current research to the transient and dynamic tasks, as well as to the general role of friction in our mechanical interactions with the environment.

Hand synergies during reach-to-grasp.

PubMed

Mason, C R; Gomez, J E; Ebner, T J

2001-12-01

An emerging viewpoint is that the CNS uses synergies to simplify the control of the hand. Previous work has shown that static hand postures for mimed grasps can be described by a few principal components in which the higher order components explained only a small fraction of the variance yet provided meaningful information. Extending that earlier work, this study addressed whether the entire act of grasp can be described by a small number of postural synergies and whether these synergies are similar for different grasps. Five right-handed adults performed five types of reach-to-grasps including power grasp, power grasp with a lift, precision grasp, and mimed power grasp and mimed precision grasp of 16 different objects. The object shapes were cones, cylinders, and spindles, systematically varied in size to produce a large range of finger joint angle combinations. Three-dimensional reconstructions of 21 positions on the hand and wrist throughout the reach-to-grasp were obtained using a four-camera video system. Singular value decomposition on the temporal sequence of the marker positions was used to identify the common patterns ("eigenpostures") across the 16 objects for each task and their weightings as a function of time. The first eigenposture explained an average of 97.3 +/- 0.89% (mean +/- SD) of the variance of the hand shape, and the second another 1.9 +/- 0.85%. The first eigenposture was characterized by an open hand configuration that opens and closes during reach. The second eigenposture contributed to the control of the thumb and long fingers, particularly in the opening of the hand during the reach and the closing in preparation for object grasp. The eigenpostures and their temporal evolutions were similar across subjects and grasps. The higher order eigenpostures, although explaining only small amounts of the variance, contributed to the movements of the fingers and thumb. These findings suggest that much of reach-to-grasp is effected using a base posture with refinements in finger and thumb positions added in time to yield unique hand shapes.

Probing the reaching-grasping network in humans through multivoxel pattern decoding.

PubMed

Di Bono, Maria Grazia; Begliomini, Chiara; Castiello, Umberto; Zorzi, Marco

2015-11-01

The quest for a putative human homolog of the reaching-grasping network identified in monkeys has been the focus of many neuropsychological and neuroimaging studies in recent years. These studies have shown that the network underlying reaching-only and reach-to-grasp movements includes the superior parieto-occipital cortex (SPOC), the anterior part of the human intraparietal sulcus (hAIP), the ventral and the dorsal portion of the premotor cortex, and the primary motor cortex (M1). Recent evidence for a wider frontoparietal network coding for different aspects of reaching-only and reach-to-grasp actions calls for a more fine-grained assessment of the reaching-grasping network in humans by exploiting pattern decoding methods (multivoxel pattern analysis--MVPA). Here, we used MPVA on functional magnetic resonance imaging (fMRI) data to assess whether regions of the frontoparietal network discriminate between reaching-only and reach-to-grasp actions, natural and constrained grasping, different grasp types, and object sizes. Participants were required to perform either reaching-only movements or two reach-to-grasp types (precision or whole hand grasp) upon spherical objects of different sizes. Multivoxel pattern analysis highlighted that, independently from the object size, all the selected regions of both hemispheres contribute in coding for grasp type, with the exception of SPOC and the right hAIP. Consistent with recent neurophysiological findings on monkeys, there was no evidence for a clear-cut distinction between a dorsomedial and a dorsolateral pathway that would be specialized for reaching-only and reach-to-grasp actions, respectively. Nevertheless, the comparison of decoding accuracy across brain areas highlighted their different contributions to reaching-only and grasping actions. Altogether, our findings enrich the current knowledge regarding the functional role of key brain areas involved in the cortical control of reaching-only and reach-to-grasp actions in humans, by revealing novel fine-grained distinctions among action types within a wide frontoparietal network.

Pencil grasp and children's handwriting legibility during different-length writing tasks.

PubMed

Dennis, J L; Swinth, Y

2001-01-01

This study examined the influence ofpencil grasp on handwriting legibility during both short and long writing tasks in 46fourth-grade students who were typically developing. Matched samples were used to controlfor variability. Regular classroom writing assignments were scoredfor word and letter legibility, and scores were compared using a mixed repeated-measures analysis of variance design. The two independent variables were pencil grasp (dynamic tripod grasp vs. atypical grasp) and task length (short vs. long). A significant difference was found between the letter legibility scores on the short task and the letter legibility scores on the long task. Students' legibility was greater on the short task than on the long task across both grasp conditions. No significant difference was found in scores between students who used dynamic tripod grasps and those who used atypical grasps, nor was there a significant interaction between grasp and task length. No significant differences were found between word legibility scores. The results indicate that although the students in this study wrote more legibly on the short task than on the long task, the type of grasp they used did not affect their legibility. Because of the limited sample size, the results of this study should be interpreted cautiously. More research in handwriting performance and pencil grasp is needed to provide clear expectations and treatment options for students.

Decoding Grasping Movements from the Parieto-Frontal Reaching Circuit in the Nonhuman Primate.

PubMed

Nelissen, Koen; Fiave, Prosper Agbesi; Vanduffel, Wim

2018-04-01

Prehension movements typically include a reaching phase, guiding the hand toward the object, and a grip phase, shaping the hand around it. The dominant view posits that these components rely upon largely independent parieto-frontal circuits: a dorso-medial circuit involved in reaching and a dorso-lateral circuit involved in grasping. However, mounting evidence suggests a more complex arrangement, with dorso-medial areas contributing to both reaching and grasping. To investigate the role of the dorso-medial reaching circuit in grasping, we trained monkeys to reach-and-grasp different objects in the dark and determined if hand configurations could be decoded from functional magnetic resonance imaging (MRI) responses obtained from the reaching and grasping circuits. Indicative of their established role in grasping, object-specific grasp decoding was found in anterior intraparietal (AIP) area, inferior parietal lobule area PFG and ventral premotor region F5 of the lateral grasping circuit, and primary motor cortex. Importantly, the medial reaching circuit also conveyed robust grasp-specific information, as evidenced by significant decoding in parietal reach regions (particular V6A) and dorsal premotor region F2. These data support the proposed role of dorso-medial "reach" regions in controlling aspects of grasping and demonstrate the value of complementing univariate with more sensitive multivariate analyses of functional MRI (fMRI) data in uncovering information coding in the brain.

Writing Forces Associated With Four Pencil Grasp Patterns in Grade 4 Children

PubMed Central

Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl

2013-01-01

OBJECTIVE. We investigated differences in handwriting kinetics, speed, and legibility among four pencil grasps after a 10-min copy task. METHOD. Seventy-four Grade 4 students completed a handwriting assessment before and after a copy task. Grip and axial forces were measured with an instrumented stylus and force-sensitive tablet. We used multiple linear regression to analyze the relationship between grasp pattern and grip and axial forces. RESULTS. We found no kinetic differences among grasps, whether considered individually or grouped by the number of fingers on the barrel. However, when grasps were grouped according to the thumb position, the adducted grasps exhibited higher mean grip and axial forces. CONCLUSION. Grip forces were generally similar across the different grasps. Kinetic differences resulting from thumb position seemed to have no bearing on speed and legibility. Interventions for handwriting difficulties should focus more on speed and letter formation than on grasp pattern. PMID:23433277

Next Gen One Portal Usability Evaluation

NASA Technical Reports Server (NTRS)

Cross, E. V., III; Perera, J. S.; Hanson, A. M.; English, K.; Vu, L.; Amonette, W.

2018-01-01

Each exercise device on the International Space Station (ISS) has a unique, customized software system interface with unique layouts / hierarchy, and operational principles that require significant crew training. Furthermore, the software programs are not adaptable and provide no real-time feedback or motivation to enhance the exercise experience and/or prevent injuries. Additionally, the graphical user interfaces (GUI) of these systems present information through multiple layers resulting in difficulty navigating to the desired screens and functions. These limitations of current exercise device GUI's lead to increased crew time spent on initiating, loading, performing exercises, logging data and exiting the system. To address these limitations a Next Generation One Portal (NextGen One Portal) Crew Countermeasure System (CMS) was developed, which utilizes the latest industry guidelines in GUI designs to provide an intuitive ease of use approach (i.e., 80% of the functionality gained within 5-10 minutes of initial use without/limited formal training required). This is accomplished by providing a consistent interface using common software to reduce crew training, increase efficiency & user satisfaction while also reducing development & maintenance costs. Results from the usability evaluations showed the NextGen One Portal UI having greater efficiency, learnability, memorability, usability and overall user experience than the current Advanced Resistive Exercise Device (ARED) UI used by astronauts on ISS. Specifically, the design of the One-Portal UI as an app interface similar to those found on the Apple and Google's App Store, assisted many of the participants in grasping the concepts of the interface with minimum training. Although the NextGen One-Portal UI was shown to be an overall better interface, observations by the test facilitators noted specific exercise tasks appeared to have a significant impact on the NextGen One-Portal UI efficiency. Future updates to the NextGen One Portal UI will address these inefficiencies.

Does a Rehabilitation Program of Aerobic and Progressive Resisted Exercises Influence HIV-Induced Distal Neuropathic Pain?

PubMed

Maharaj, Sonill S; Yakasai, Abdulsalam M

2018-05-01

Distal symmetrical polyneuropathy is a common neurological sequela after HIV, which leads to neuropathic pain and functional limitations. Rehabilitation programs with exercises are used to augment pharmacological therapy to relieve pain but appropriate and effective exercises are unknown. This study explored the safety and effect of moderate-intensity aerobic exercises and progressive resisted exercises for HIV-induced distal symmetrical polyneuropathy neuropathic pain. A randomized pretest, posttest of 12 wks of aerobic exercise or progressive resisted exercise compared with a control. Outcome measures were assessed using the subjective periphery neuropathy, brief peripheral neuropathy screening, and numeric pain rating scale. Pain was assessed at baseline, 6 and 12 wks. Data between groups were compared using Kruskal-Wallis, Mann-Whitney U test, and within-groups Friedman and Wilcoxon signed rank tests. There were 136 participants (mean [SD] age = 36.79 [8.23] yrs) and the exercise groups completed the protocols without any adverse effects. Pain scores within and between aerobic exercise and progressive resisted exercise groups showed significant improvement (P < 0.05) from baseline to 6 and 12 wks compared with the control (P > 0.05). This study supports a rehabilitation program of moderate-intensity aerobic exercise and progressive resisted exercise being safe and effective for reducing neuropathic pain and is beneficial with analgesics for HIV-induced distal symmetrical polyneuropathy.

The observation of manual grasp actions affects the control of speech: a combined behavioral and Transcranial Magnetic Stimulation study.

PubMed

Gentilucci, Maurizio; Campione, Giovanna Cristina; Dalla Volta, Riccardo; Bernardis, Paolo

2009-12-01

Does the mirror system affect the control of speech? This issue was addressed in behavioral and Transcranial Magnetic Stimulation (TMS) experiments. In behavioral experiment 1, participants pronounced the syllable /da/ while observing (1) a hand grasping large and small objects with power and precision grasps, respectively, (2) a foot interacting with large and small objects and (3) differently sized objects presented alone. Voice formant 1 was higher when observing power as compared to precision grasp, whereas it remained unaffected by observation of the different types of foot interaction and objects alone. In TMS experiment 2, we stimulated hand motor cortex, while participants observed the two types of grasp. Motor Evoked Potentials (MEPs) of hand muscles active during the two types of grasp were greater when observing power than precision grasp. In experiments 3-5, TMS was applied to tongue motor cortex of participants silently pronouncing the syllable /da/ and simultaneously observing power and precision grasps, pantomimes of the two types of grasps, and differently sized objects presented alone. Tongue MEPs were greater when observing power than precision grasp either executed or pantomimed. Finally, in TMS experiment 6, the observation of foot interaction with large and small objects did not modulate tongue MEPs. We hypothesized that grasp observation activated motor commands to the mouth as well as to the hand that were congruent with the hand kinematics implemented in the observed type of grasp. The commands to the mouth selectively affected postures of phonation organs and consequently basic features of phonological units.

Neural correlates of action perception at the onset of functional grasping

PubMed Central

Daum, Moritz M.; Handl, Andrea; Gredebäck, Gustaf

2015-01-01

Event-related potentials were recorded while infants observe congruent or incongruent grasping actions at the age when organized grasping first emerges (4–6 months of age). We demonstrate that the event-related potential component P400 encodes the congruency of power grasps at the age of 6 months (Experiment 1) and in 5-month-old infants that have developed the ability to use power grasps (Experiment 2). This effect does not extend to precision grasps, which infants cannot perform (Experiment 3). Our findings suggest that infants’ encoding of the relationship between an object and a grasping hand (the action–perception link) is highly specialized to actions and manual configurations of actions that infants are able to perform. PMID:25193947

An introductory study of common grasps used by adults during performance of activities of daily living.

PubMed

Vergara, Margarita; Sancho-Bru, J L; Gracia-Ibáñez, V; Pérez-González, A

2014-01-01

This paper presents the results of a descriptive survey on human grasps. Sixty-four videos were selected to represent tasks performed in the main areas of activities of daily living (ADL) (personal care, meal preparation, eating, housekeeping, etc.). All the participants were right-handed. Elementary grasps were identified for each hand, and the grasp type (from a 9-type classification), the hands involved, and the duration were registered for each case. The results show that the most commonly used grasps are: pinch, non-prehensile, cylindrical, lateral pinch and lumbrical. The presence of these grasps in the areas of ADL is, however, very different (e.g., pinch is widely used in food preparation and very little in driving). Some grasps were used more frequently with one hand or when both hands were used simultaneously (e.g., special pinch was hardly used by the left hand). Knowing the grasp types most frequently used in ADL is essential to be able to assess grasp rehabilitation processes or hand prostheses development. Copyright © 2014 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Fast grasping of unknown objects using cylinder searching on a single point cloud

NASA Astrophysics Data System (ADS)

Lei, Qujiang; Wisse, Martijn

2017-03-01

Grasping of unknown objects with neither appearance data nor object models given in advance is very important for robots that work in an unfamiliar environment. The goal of this paper is to quickly synthesize an executable grasp for one unknown object by using cylinder searching on a single point cloud. Specifically, a 3D camera is first used to obtain a partial point cloud of the target unknown object. An original method is then employed to do post treatment on the partial point cloud to minimize the uncertainty which may lead to grasp failure. In order to accelerate the grasp searching, surface normal of the target object is then used to constrain the synthetization of the cylinder grasp candidates. Operability analysis is then used to select out all executable grasp candidates followed by force balance optimization to choose the most reliable grasp as the final grasp execution. In order to verify the effectiveness of our algorithm, Simulations on a Universal Robot arm UR5 and an under-actuated Lacquey Fetch gripper are used to examine the performance of this algorithm, and successful results are obtained.

Dose-response relationship of the cardiovascular adaptation to endurance training in healthy adults: how much training for what benefit?

PubMed

Iwasaki, Ken-Ichi; Zhang, Rong; Zuckerman, Julie H; Levine, Benjamin D

2003-10-01

Occupational or recreational exercise reduces mortality from cardiovascular disease. The potential mechanisms for this reduction may include changes in blood pressure (BP) and autonomic control of the circulation. Therefore, we conducted the present long-term longitudinal study to quantify the dose-response relationship between the volume and intensity of exercise training, and regulation of heart rate (HR) and BP. We measured steady-state hemodynamics and analyzed dynamic cardiovascular regulation by spectral and transfer function analysis of cardiovascular variability in 11 initially sedentary subjects during 1 yr of progressive endurance training sufficient to allow them to complete a marathon. From this, we found that 1) moderate exercise training for 3 mo decreased BP, HR, and total peripheral resistance, and increased cardiovascular variability and arterial baroreflex sensitivity; 2) more prolonged and intense training did not augment these changes further; and 3) most of these changes returned to control values at 12 mo despite markedly increased training duration and intensity equivalent to that routinely observed in competitive athletes. In conclusion, increases in R-wave-R-wave interval and cardiovascular variability indexes are consistent with an augmentation of vagal modulation of HR after exercise training. It appears that moderate doses of training for 3 mo are sufficient to achieve this response as well as a modest hypotensive effect from decreasing vascular resistance. However, more prolonged and intense training does not necessarily lead to greater enhancement of circulatory control and, therefore, may not provide an added protective benefit via autonomic mechanisms against death by cardiovascular disease.

Importance of compensatory heart rate increase during myocardial ischemia to preserve appropriate oxygen kinetics.

PubMed

Yoshida, Sadamitsu; Adachi, Hitoshi; Murata, Makoto; Tomono, Junichi; Oshima, Shigeru; Kurabayashi, Masahiko

2017-09-01

Myocardial ischemia induces cardiac dysfunction, resulting in insufficient oxygen supply to peripheral tissues and mismatched energy production during exercise. To relieve the insufficient oxygen supply, heart rate (HR) response is augmented; however, beta-adrenergic receptor blockers (BB) restrict HR response. Although BB are essential drugs for angina pectoris, the effect of BB on exercise tolerance in patients with angina has not been studied. The aim of this study was to clarify the importance of HR augmentation to preserve exercise tolerance in patients with angina pectoris. Forty-two subjects who underwent cardiopulmonary exercise testing (CPX) to detect myocardial ischemia were enrolled. CPX was performed until exhaustion or onset of significant myocardial ischemia using a ramp protocol. Subjects were assigned to three groups (Group A: with ST depression during CPX with significant coronary stenosis and taking BB; Group B: with ST depression and not taking BB; Group C: without ST depression and not taking BB). HR response to exercise was evaluated during the following two periods: below and above ischemic threshold (IT). In Group C, it was evaluated during the first 2min and the last 2min of a ramp exercise. No significant differences were observed among the three groups with regard to patients' basic characteristics. Below IT, there were no differences in oxygen pulse/watt (O 2 pulse increasing rate), HR/watt (ΔHR/ΔWR), and ΔV˙O 2 /ΔWR. Above IT, O 2 pulse increasing rate was greater in Group A than in Group B. ΔHR/ΔWR was smaller in Group A than in Group B. ΔV˙O 2 /ΔWR became smaller in Group A than in Group B. There was no difference in anaerobic threshold, and peak V˙O 2 was smaller in Group A than in Group B. Restriction of HR response by a BB is shown to be one of the important factors in diminished exercise tolerance. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

RoboGlove - A Robonaut Derived Multipurpose Assistive Device

NASA Technical Reports Server (NTRS)

Diftler, Myron; Ihrke, C. A.; Bridgwater, L. B.; Davis, D. R.; Linn, D. M.; Laske, E. A.; Ensley, K. G.; Lee, J. H.

2014-01-01

The RoboGlove is an assistive device that can augment human strength, endurance or provide directed motion for use in rehabilitation. RoboGlove is a spinoff of the highly successful Robonaut 2 (R2) system developed as part of a partnership between General Motors and NASA. This extremely lightweight device employs an actuator system based on the R2 finger drive system to transfer part or the entire grasp load from human tendons to artificial ones contained in the glove. Steady state loads ranging from 15 to 20 lbs. and peaks approaching 50 lbs. are achievable. The technology holds great promise for use with space suit gloves to reduce fatigue during space walks. Tactile sensing, miniaturized electronics, and on-board processing provide sufficient flexibility for applications in many industries. The following describes the design, mechanical/electrical integration, and control features of the glove.

Effect of preexercise ingestion of modified cornstarch on substrate oxidation during endurance exercise.

PubMed

Johannsen, Neil M; Sharp, Rick L

2007-06-01

The purpose of this study was to investigate differences in substrate oxidation between dextrose (DEX) and unmodified (UAMS) and acid/alcohol-modified (MAMS) cornstarches. Seven endurance-trained men (VO2peak = 59.1 +/- 5.4 mL.kg-1.min-1) participated in 2 h of exercise (66.4% +/- 3.3% VO2peak) 30 min after ingesting 1 g/kg body weight of the experimental carbohydrate or placebo (PLA). Plasma glucose and insulin were elevated after DEX (P < 0.05) compared with UAMS, MAMS, and PLA. Although MAMS and DEX raised carbohydrate oxidation rate through 90 min of exercise, only MAMS persisted throughout 120 min (P < 0.05 compared with all trials). Exogenous-carbohydrate oxidation rate was higher in DEX than in MAMS and UAMS until 90 min of exercise. Acid/alcohol modification resulted in augmented carbohydrate oxidation with a small, sustained increase in exogenous-carbohydrate oxidation rate. MAMS appears to be metabolizable and available for oxidation during exercise.

Mena-GRASP65 interaction couples actin polymerization to Golgi ribbon linking.

PubMed

Tang, Danming; Zhang, Xiaoyan; Huang, Shijiao; Yuan, Hebao; Li, Jie; Wang, Yanzhuang

2016-01-01

In mammalian cells, the Golgi reassembly stacking protein 65 (GRASP65) has been implicated in both Golgi stacking and ribbon linking by forming trans-oligomers through the N-terminal GRASP domain. Because the GRASP domain is globular and relatively small, but the gaps between stacks are large and heterogeneous, it remains puzzling how GRASP65 physically links Golgi stacks into a ribbon. To explore the possibility that other proteins may help GRASP65 in ribbon linking, we used biochemical methods and identified the actin elongation factor Mena as a novel GRASP65-binding protein. Mena is recruited onto the Golgi membranes through interaction with GRASP65. Depleting Mena or disrupting actin polymerization resulted in Golgi fragmentation. In cells, Mena and actin were required for Golgi ribbon formation after nocodazole washout; in vitro, Mena and microfilaments enhanced GRASP65 oligomerization and Golgi membrane fusion. Thus Mena interacts with GRASP65 to promote local actin polymerization, which facilitates Golgi ribbon linking. © 2016 Tang et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Learning Grasp Strategies Composed of Contact Relative Motions

NASA Technical Reports Server (NTRS)

Platt, Robert, Jr.

2007-01-01

Of central importance to grasp synthesis algorithms are the assumptions made about the object to be grasped and the sensory information that is available. Many approaches avoid the issue of sensing entirely by assuming that complete information is available. In contrast, this paper proposes an approach to grasp synthesis expressed in terms of units of control that simultaneously change the contact configuration and sense information about the object and the relative manipulator-object pose. These units of control, known as contact relative motions (CRMs), allow the grasp synthesis problem to be recast as an optimal control problem where the goal is to find a strategy for executing CRMs that leads to a grasp in the shortest number of steps. An experiment is described that uses Robonaut, the NASA-JSC space humanoid, to show that CRMs are a viable means of synthesizing grasps. However, because of the limited amount of information that a single CRM can sense, the optimal control problem may be partially observable. This paper proposes expressing the problem as a k-order Markov Decision Process (MDP) and solving it using Reinforcement Learning. This approach is tested in a simulation of a two-contact manipulator that learns to grasp an object. Grasp strategies learned in simulation are tested on the physical Robonaut platform and found to lead to grasp configurations consistently.

Comparison of stiffness and interface pressure during rest and exercise among various arm sleeves.

PubMed

Hirai, M; Niimi, K; Iwata, H; Sugimoto, I; Ishibashi, H; Ota, T; Nakamura, H

2010-08-01

To compare the interface pressure during rest and exercise among various kinds of arm sleeves. The interface pressure underneath nine different arm sleeves was measured during 10 maximal opening and closing movements of fingers using a pressure transducer (Air Pack Type Analyser) in 16 healthy volunteers. Furthermore, in order to evaluate the characteristics of each arm sleeve, the extensibility, stiffness and thickness were determined in vitro by several apparatuses. There was a significant correlation between stiffness and extensibility. The stiffness was significantly correlated with the pressure difference between muscle contraction and relaxation during exercise. The higher the value of stiffness, the greater the pressure amplitude during exercise. Short-stretch arm sleeves characterized with a high level stiffness, including thick round- and flat-knitted arm sleeves, are more beneficial for the augmentation of muscle pumping than long-stretch arm sleeves, in the same way as short-stretch bandages or stockings applied to the leg.

Grasping with the eyes of your hands: hapsis and vision modulate hand preference.

PubMed

Stone, Kayla D; Gonzalez, Claudia L R

2014-02-01

Right-hand preference has been demonstrated for visually guided reaching and grasping. Grasping, however, requires the integration of both visual and haptic cues. To what extent does vision influence hand preference for grasping? Is there a hand preference for haptically guided grasping? Two experiments were designed to address these questions. In Experiment 1, individuals were tested in a reaching-to-grasp task with vision (sighted condition) and with hapsis (blindfolded condition). Participants were asked to put together 3D models using building blocks scattered on a tabletop. The models were simple, composed of ten blocks of three different shapes. Starting condition (Vision-First or Hapsis-First) was counterbalanced among participants. Right-hand preference was greater in visually guided grasping but only in the Vision-First group. Participants who initially built the models while blindfolded (Hapsis-First group) used their right hand significantly less for the visually guided portion of the task. To investigate whether grasping using hapsis modifies subsequent hand preference, participants received an additional haptic experience in a follow-up experiment. While blindfolded, participants manipulated the blocks in a container for 5 min prior to the task. This additional experience did not affect right-hand use on visually guided grasping but had a robust effect on haptically guided grasping. Together, the results demonstrate first that hand preference for grasping is influenced by both vision and hapsis, and second, they highlight how flexible this preference could be when modulated by hapsis.

Chronic inhibition of nitric oxide synthase augments the ACTH response to exercise

PubMed Central

Jankord, Ryan; McAllister, Richard M.; Ganjam, Venkataseshu K.; Laughlin, M. Harold

2009-01-01

Exercise can activate the hypothalamo-pituitary-adrenocortical (HPA) axis, and regular exercise training can impact how the HPA axis responds to stress. The mechanism by which acute exercise induces HPA activity is unclear. Therefore, the purpose of this study was to test the hypothesis that nitric oxide modulates the neuroendocrine component of the HPA axis during exercise. Female Yucatan miniature swine were treated with N-nitro-l-arginine methyl ester (l-NAME) to test the effect of chronic nitric oxide synthase (NOS) inhibition on the ACTH response to exercise. In addition, we tested the effect of NOS inhibition on blood flow to tissues of the HPA axis and report the effects of handling and treadmill exercise on the plasma concentrations of ACTH and cortisol. Chronic NOS inhibition decreased plasma NOx levels by 44%, increased mean arterial blood pressure by 46%, and increased expression of neuronal NOS in carotid arteries. Vascular conductance was decreased in the frontal cortex, the hypothalamus, and the adrenal gland. Chronic NOS inhibition exaggerated the ACTH response to exercise. In contrast, chronic NOS inhibition decreased the ACTH response to restraint, suggesting that the role of NO in modulating HPA activity is stressor dependent. These results demonstrate that NOS activity modulates the response of the neuroendocrine component of the HPA axis during exercise stress. PMID:19144752

Chronic inhibition of nitric oxide synthase augments the ACTH response to exercise.

PubMed

Jankord, Ryan; McAllister, Richard M; Ganjam, Venkataseshu K; Laughlin, M Harold

2009-03-01

Exercise can activate the hypothalamo-pituitary-adrenocortical (HPA) axis, and regular exercise training can impact how the HPA axis responds to stress. The mechanism by which acute exercise induces HPA activity is unclear. Therefore, the purpose of this study was to test the hypothesis that nitric oxide modulates the neuroendocrine component of the HPA axis during exercise. Female Yucatan miniature swine were treated with N-nitro-l-arginine methyl ester (l-NAME) to test the effect of chronic nitric oxide synthase (NOS) inhibition on the ACTH response to exercise. In addition, we tested the effect of NOS inhibition on blood flow to tissues of the HPA axis and report the effects of handling and treadmill exercise on the plasma concentrations of ACTH and cortisol. Chronic NOS inhibition decreased plasma NO(x) levels by 44%, increased mean arterial blood pressure by 46%, and increased expression of neuronal NOS in carotid arteries. Vascular conductance was decreased in the frontal cortex, the hypothalamus, and the adrenal gland. Chronic NOS inhibition exaggerated the ACTH response to exercise. In contrast, chronic NOS inhibition decreased the ACTH response to restraint, suggesting that the role of NO in modulating HPA activity is stressor dependent. These results demonstrate that NOS activity modulates the response of the neuroendocrine component of the HPA axis during exercise stress.

Effects of Exercise in Immersive Virtual Environments on Cortical Neural Oscillations and Mental State

PubMed Central

Vogt, Tobias; Herpers, Rainer; Askew, Christopher D.; Scherfgen, David; Strüder, Heiko K.; Schneider, Stefan

2015-01-01

Virtual reality environments are increasingly being used to encourage individuals to exercise more regularly, including as part of treatment those with mental health or neurological disorders. The success of virtual environments likely depends on whether a sense of presence can be established, where participants become fully immersed in the virtual environment. Exposure to virtual environments is associated with physiological responses, including cortical activation changes. Whether the addition of a real exercise within a virtual environment alters sense of presence perception, or the accompanying physiological changes, is not known. In a randomized and controlled study design, moderate-intensity Exercise (i.e., self-paced cycling) and No-Exercise (i.e., automatic propulsion) trials were performed within three levels of virtual environment exposure. Each trial was 5 minutes in duration and was followed by posttrial assessments of heart rate, perceived sense of presence, EEG, and mental state. Changes in psychological strain and physical state were generally mirrored by neural activation patterns. Furthermore, these changes indicated that exercise augments the demands of virtual environment exposures and this likely contributed to an enhanced sense of presence. PMID:26366305

Effects of Exercise in Immersive Virtual Environments on Cortical Neural Oscillations and Mental State.

PubMed

Vogt, Tobias; Herpers, Rainer; Askew, Christopher D; Scherfgen, David; Strüder, Heiko K; Schneider, Stefan

2015-01-01

Virtual reality environments are increasingly being used to encourage individuals to exercise more regularly, including as part of treatment those with mental health or neurological disorders. The success of virtual environments likely depends on whether a sense of presence can be established, where participants become fully immersed in the virtual environment. Exposure to virtual environments is associated with physiological responses, including cortical activation changes. Whether the addition of a real exercise within a virtual environment alters sense of presence perception, or the accompanying physiological changes, is not known. In a randomized and controlled study design, moderate-intensity Exercise (i.e., self-paced cycling) and No-Exercise (i.e., automatic propulsion) trials were performed within three levels of virtual environment exposure. Each trial was 5 minutes in duration and was followed by posttrial assessments of heart rate, perceived sense of presence, EEG, and mental state. Changes in psychological strain and physical state were generally mirrored by neural activation patterns. Furthermore, these changes indicated that exercise augments the demands of virtual environment exposures and this likely contributed to an enhanced sense of presence.

Saxagliptin Restores Vascular Mitochondrial Exercise Response in the Goto-Kakizaki Rat

PubMed Central

Keller, Amy C.; Knaub, Leslie A.; Miller, Matthew W.; Birdsey, Nicholas; Klemm, Dwight J.

2015-01-01

Abstract: Cardiovascular disease risk and all-cause mortality are largely predicted by physical fitness. Exercise stimulates vascular mitochondrial biogenesis through endothelial nitric oxide synthase (eNOS), sirtuins, and PPARγ coactivator 1α (PGC-1α), a response absent in diabetes and hypertension. We hypothesized that an agent regulating eNOS in the context of diabetes could reconstitute exercise-mediated signaling to mitochondrial biogenesis. Glucagon-like peptide 1 (GLP-1) stimulates eNOS and blood flow; we used saxagliptin, an inhibitor of GLP-1 degradation, to test whether vascular mitochondrial adaptation to exercise in diabetes could be restored. Goto-Kakizaki (GK) rats, a nonobese, type 2 diabetes model, and Wistar controls were exposed to an 8-day exercise intervention with or without saxagliptin (10 mg·kg−1·d−1). We evaluated the impact of exercise and saxagliptin on mitochondrial proteins and signaling pathways in aorta. Mitochondrial protein expression increased with exercise in the Wistar aorta and decreased or remained unchanged in the GK animals. GK rats treated with saxagliptin plus exercise showed increased expression of mitochondrial complexes, cytochrome c, eNOS, nNOS, PGC-1α, and UCP3 proteins. Notably, a 3-week saxagliptin plus exercise intervention significantly increased running time in the GK rats. These data suggest that saxagliptin restores vascular mitochondrial adaptation to exercise in a diabetic rodent model and may augment the impact of exercise on the vasculature. PMID:25264749

Saxagliptin restores vascular mitochondrial exercise response in the Goto-Kakizaki rat.

PubMed

Keller, Amy C; Knaub, Leslie A; Miller, Matthew W; Birdsey, Nicholas; Klemm, Dwight J; Reusch, Jane E B

2015-02-01

Cardiovascular disease risk and all-cause mortality are largely predicted by physical fitness. Exercise stimulates vascular mitochondrial biogenesis through endothelial nitric oxide synthase (eNOS), sirtuins, and PPARγ coactivator 1α (PGC-1α), a response absent in diabetes and hypertension. We hypothesized that an agent regulating eNOS in the context of diabetes could reconstitute exercise-mediated signaling to mitochondrial biogenesis. Glucagon-like peptide 1 (GLP-1) stimulates eNOS and blood flow; we used saxagliptin, an inhibitor of GLP-1 degradation, to test whether vascular mitochondrial adaptation to exercise in diabetes could be restored. Goto-Kakizaki (GK) rats, a nonobese, type 2 diabetes model, and Wistar controls were exposed to an 8-day exercise intervention with or without saxagliptin (10 mg·kg·d). We evaluated the impact of exercise and saxagliptin on mitochondrial proteins and signaling pathways in aorta. Mitochondrial protein expression increased with exercise in the Wistar aorta and decreased or remained unchanged in the GK animals. GK rats treated with saxagliptin plus exercise showed increased expression of mitochondrial complexes, cytochrome c, eNOS, nNOS, PGC-1α, and UCP3 proteins. Notably, a 3-week saxagliptin plus exercise intervention significantly increased running time in the GK rats. These data suggest that saxagliptin restores vascular mitochondrial adaptation to exercise in a diabetic rodent model and may augment the impact of exercise on the vasculature.

The destination defines the journey: an examination of the kinematics of hand-to-mouth movements

PubMed Central

Gonzalez, Claudia L. R.

2016-01-01

Long-train electrical stimulation of the motor and premotor cortices of nonhuman primates can produce either hand-to-mouth or grasp-to-inspect movements, depending on the precise location of stimulation. Furthermore, single-neuron recording studies identify discrete neuronal populations in the inferior parietal and ventral premotor cortices that respond uniquely to either grasp-to-eat or grasp-to-place movements, despite their identical mechanistic requirements. These studies demonstrate that the macaque motor cortex is organized around producing functional, goal-oriented movements, rather than simply fulfilling muscular prerequisites of action. In humans, right-handed hand-to-mouth movements have a unique kinematic signature; smaller maximum grip apertures are produced when grasping to eat than when grasping to place identical targets. This is evidence that the motor cortex in humans is also organized around producing functional movements. However, in both macaques and humans, grasp-to-eat/hand-to-mouth movements have always been elicited using edible targets and have (necessarily) been paired with mouth movement. It is therefore unknown whether the kinematic distinction is a natural result of grasping food and/or is simply attributable to concurrent opening of the mouth while grasping. In experiment 1, we used goal-differentiated grasping tasks, directed toward edible and inedible targets, to show that the unique kinematic signature is present even with inedible targets. In experiment 2, we used the same goal-differentiated grasping tasks, either coupled with or divorced from an open-mouth movement, to show that the signature is not attributable merely to a planned opening of the mouth during the grasp. These results are discussed in relation to the role of hand-to-mouth movements in human development, independently of grasp-to-eat behavior. PMID:27512020

Mirror system activity for action and language is embedded in the integration of dorsal and ventral pathways.

PubMed

Arbib, Michael A

2010-01-01

We develop the view that the involvement of mirror neurons in embodied experience grounds brain structures that underlie language, but that many other brain regions are involved. We stress the cooperation between the dorsal and ventral streams in praxis and language. Both have perceptual and motor schemas but the perceptual schemas in the dorsal path are affordances linked to specific motor schemas for detailed motor control, whereas the ventral path supports planning and decision making. This frames the hypothesis that the mirror system for words evolved from the mirror system for actions to support words-as-phonological-actions, with semantics provided by the linkage to neural systems supporting perceptual and motor schemas. We stress the importance of computational models which can be linked to the parametric analysis of data and conceptual analysis of these models to support new patterns of understanding of the data. In the domain of praxis, we assess the FARS model of the canonical system for grasping, the MNS models for the mirror system for grasping, and the Augmented Competitive Queuing model that extends the control of action to the opportunistic scheduling of action sequences and also offers a new hypothesis on the role of mirror neurons in self action. Turning to language, we use Construction Grammar as our linguistic framework to get beyond single words to phrases and sentences, and initiate analysis of what brain functions must complement mirror systems to support this functionality. 2009 Elsevier Inc. All rights reserved.

Tactility as a function of grasp force: Effects of glove, orientation, pressure, load, and handle

NASA Technical Reports Server (NTRS)

Bishu, Ram R.; Bronkema, Lisa A.; Garcia, Dishayne; Klute, Glenn; Rajulu, Sudhakar

1994-01-01

One of the reasons for reduction in performance when gloves are donned is the lack of tactile sensitivity. It was argued that grasping force for a weight to be grasped will be a function of the weight to be lifted and the hand conditions. It was further reasoned that the differences in grasping force for various hand conditions will be a correlate of the tactile sensitivity of the corresponding hand conditions. The objective of this experiment, therefore, was to determine the effects of glove type, pressure, and weight of load on the initial grasping force and stable grasping force. It was hypothesized that when a person grasps an object, he/she grasps very firmly initially and then releases the grasp slightly after realizing what force is needed to maintain a steady grasp. This would seem to be particularly true when a person is wearing a glove and has lost some tactile sensitivity and force feedback during the grasp. Therefore, the ratio of initial force and stable force and the stable force itself would represent the amount of tactile adjustment that is made when picking up an object, and this adjustment should vary with the use of gloves. A dynamometer was fabricated to measure the grasping force; the tests were performed inside a glove box. Four female and four male subjects participated in the study, which measured the effects of four variables: load effect, gender effect, glove type, and pressure variance. The only significant effects on the peak and stable force were caused by gender and the weight of the load lifted. Neither gloves nor pressure altered these forces when compared to a bare-handed condition, as was suspected before the test. It is possible that gloves facilitate in holding due to coefficient of friction while they deter in peak grasp strength.

Coordination of pincer grasp and transport after mechanical perturbation of the index finger

PubMed Central

Schettino, Luis F.; Adamovich, Sergei V.

2017-01-01

Our understanding of reach-to-grasp movements has evolved from the original formulation of the movement as two semi-independent visuomotor channels to one of interdependence. Despite a number of important contributions involving perturbations of the reach or the grasp, some of the features of the movement, such as the presence or absence of coordination between the digits during the pincer grasp and the extent of spatio-temporal interdependence between the transport and the grasp, are still unclear. In this study, we physically perturbed the index finger into extension during grasping closure on a minority of trials to test whether modifying the movement of one digit would affect the movement of the opposite digit, suggestive of an overarching coordinative process. Furthermore, we tested whether disruption of the grasp results in the modification of kinematic parameters of the transport. Our results showed that a continuous perturbation to the index finger affected wrist velocity but not lateral displacement. Moreover, we found that the typical flexion of the thumb observed in nonperturbed trials was delayed until the index finger counteracted the extension force. These results suggest that physically perturbing the grasp modifies the kinematics of the transport component, indicating a two-way interdependence of the reach and the grasp. Furthermore, a perturbation to one digit affects the kinematics of the other, supporting a model of grasping in which the digits are coordinated by a higher-level process rather than being independently controlled. NEW & NOTEWORTHY A current debate concerning the neural control of prehension centers on the question of whether the digits in a pincer grasp are controlled individually or together. Employing a novel approach that perturbs mechanically the grasp component during a natural reach-to-grasp movement, this work is the first to test a key hypothesis: whether perturbing one of the digits during the movement affects the other. Our results support the idea that the digits are not independently controlled. PMID:28331008

Grasp with hand and mouth: a kinematic study on healthy subjects.

PubMed

Gentilucci, M; Benuzzi, F; Gangitano, M; Grimaldi, S

2001-10-01

Neurons involved in grasp preparation with hand and mouth were previously recorded in the premotor cortex of monkey. The aim of the present kinematic study was to determine whether a unique planning underlies the act of grasping with hand and mouth in humans as well. In a set of four experiments, healthy subjects reached and grasped with the hand an object of different size while opening the mouth (experiments 1 and 3), or extending the other forearm (experiment 4), or the fingers of the other hand (experiment 5). In a subsequent set of three experiments, subjects grasped an object of different size with the mouth, while opening the fingers of the right hand (experiments 6-8). The initial kinematics of mouth and finger opening, but not of forearm extension, was affected by the size of the grasped object congruently with the size effect on initial grasp kinematics. This effect was due neither to visual presentation of the object, without the successive grasp motor act (experiment 2) nor to synchronism between finger and mouth opening (experiments 3, 7, and 8). In experiment 9 subjects grasped with the right hand an object of different size while pronouncing a syllable printed on the target. Mouth opening and sound production were affected by the grasped object size. The results of the present study are discussed according to the notion that in an action each motor act is prepared before the beginning of the motor sequence. Double grasp preparation can be used for successive motor acts on the same object as, for example, grasping food with the hand and ingesting it after bringing it to the mouth. We speculate that the circuits involved in double grasp preparation might have been the neural substrate where hand motor patterns used as primitive communication signs were transferred to mouth articulation system. This is in accordance with the hypothesis that Broca's area derives phylogenetically from the monkey premotor area where hand movements are controlled.

Clinical relevance of the effects of reach-to-grasp training using trunk restraint in individuals with hemiparesis poststroke: A systematic review.

PubMed

Greisberger, Andrea; Aviv, Hanna; Garbade, Sven F; Diermayr, Gudrun

2016-04-28

To evaluate the evidence for, and clinical relevance of, immediate and long-term effects of trunk restraint during reach-to-grasp training poststroke on movement patterns and functional abilities within the framework of the International Classification of Functioning, Disability and Health. PubMed, Web of Science, CINAHL, Embase, PEDro, Cochrane Library (publication dates January 1985 to March 2015). Randomized controlled trials comparing training using trunk restraint with any other exercise training. Data were extracted by one researcher and checked by two other researchers. The Cochrane Collaboration's tool for assessing risk of bias and the Physiotherapy Evidence Database scale were used by two researchers to assess study quality and risk of bias. Eight studies met the inclusion criteria. Five studies found better recovery of movement patterns (trunk displacement, elbow extension, and/or shoulder flexion - body function/structure) at post-test in the experimental compared with the control groups. Functional abilities (activity/participation) improved more in the experimental groups in 3 studies at post-test. Long-term effects were found in one study after 4 weeks. Trunk restraint has immediate and some long-term effects in adults with chronic stroke. However, these effects are not consistently clinically relevant when referring to minimal detectable change or minimal clinically important difference values.

Grasp frequency and usage in daily household and machine shop tasks.

PubMed

Bullock, Ian M; Zheng, Joshua Z; De La Rosa, Sara; Guertler, Charlotte; Dollar, Aaron M

2013-01-01

In this paper, we present results from a study of prehensile human hand use during the daily work activities of four subjects: two housekeepers and two machinists. Subjects wore a head-mounted camera that recorded their hand usage during their daily work activities in their typical place of work. For each subject, 7.45 hours of video was analyzed, recording the type of grasp being used and its duration. From this data, we extracted overall grasp frequency, duration distributions for each grasp, and common transitions between grasps. The results show that for 80 percent of the study duration the housekeepers used just five grasps and the machinists used 10. The grasping patterns for the different subjects were compared, and the overall top 10 grasps are discussed in detail. The results of this study not only lend insight into how people use their hands during daily tasks, but can also inform the design of effective robotic and prosthetic hands.

Writing forces associated with four pencil grasp patterns in grade 4 children.

PubMed

Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl; Chau, Tom

2013-01-01

OBJECTIVE. We investigated differences in handwriting kinetics, speed, and legibility among four pencil grasps after a 10-min copy task. METHOD. Seventy-four Grade 4 students completed a handwriting assessment before and after a copy task. Grip and axial forces were measured with an instrumented stylus and force-sensitive tablet. We used multiple linear regression to analyze the relationship between grasp pattern and grip and axial forces. RESULTS. We found no kinetic differences among grasps, whether considered individually or grouped by the number of fingers on the barrel. However, when grasps were grouped according to the thumb position, the adducted grasps exhibited higher mean grip and axial forces. CONCLUSION. Grip forces were generally similar across the different grasps. Kinetic differences resulting from thumb position seemed to have no bearing on speed and legibility. Interventions for handwriting difficulties should focus more on speed and letter formation than on grasp pattern. Copyright © 2013 by the American Occupational Therapy Association, Inc.

Augmentation plating in hypertrophic non-union after nail fixation of femoral shaft fracture compared with exchange plating.

PubMed

Jiang, Liangjun; Pan, Zhijun; Zheng, Qiang

2014-01-01

Augmentation plating has been used successfully to treat hypertrophic non-union after nail fixation. This study compared the efficacy of augmentation plating and exchange plating for treating hypertrophic non-union of femoral shaft fracture after intramedullary nail fixation. A total of 12 patients received augmentation plating and 15 patients received exchange plating as treatment for femoral shaft hypertrophic non-union. The procedures were conducted at our medical centre between January 2005 and January 2012. Clinical follow-up was conducted at 2 weeks, 1 month and then monthly until union was achieved to compare union time, operation time, bleeding and complications between the two groups. All patients underwent follow-up examinations until fracture union was achieved. The average length of follow-up time after the second treatment was (18.37 ± 3.28) months. The time needed for union was (4.17 ± 0.94) months in the augmentation plating group and (5.33 ± 1.72) months in the exchange plating group. The operation time was (90.00 ± 17.58) minutes in the augmentation plating group and (160.00 ± 25.35) minutes in the exchange plating group. The amount of blood loss during the operation was (270.00 ± 43.32) ml in the augmentation plating group and (530.00 ± 103.65) ml in the exchange plating group. Both groups showed significant difference (P < 0.05) in their results. No complications were reported after the second operation. Augmentation plating after nail fixation could remove local rotation instability, facilitate simple operation, create minimal damage and enable exercise for early functional recovery. Therefore, augmentation plating is excellent for treating hypertrophic non-union after nail fixation in femoral shaft fracture.

Effects of fasted vs fed-state exercise on performance and post-exercise metabolism: A systematic review and meta-analysis.

PubMed

Aird, T P; Davies, R W; Carson, B P

2018-05-01

The effects of nutrition on exercise metabolism and performance remain an important topic among sports scientists, clinical, and athletic populations. Recently, fasted exercise has garnered interest as a beneficial stimulus which induces superior metabolic adaptations to fed exercise in key peripheral tissues. Conversely, pre-exercise feeding augments exercise performance compared with fasting conditions. Given these seemingly divergent effects on performance and metabolism, an appraisal of the literature is warranted. This review determined the effects of fasting vs pre-exercise feeding on continuous aerobic and anaerobic or intermittent exercise performance, and post-exercise metabolic adaptations. A search was performed using the MEDLINE and PubMed search engines. The literature search identified 46 studies meeting the relevant inclusion criteria. The Delphi list was used to assess study quality. A meta-analysis and meta-regression were performed where appropriate. Findings indicated that pre-exercise feeding enhanced prolonged (P = .012), but not shorter duration aerobic exercise performance (P = .687). Fasted exercise increased post-exercise circulating FFAs (P = .023) compared to fed exercise. It is evidenced that pre-exercise feeding blunted signaling in skeletal muscle and adipose tissue implicated in regulating components of metabolism, including mitochondrial adaptation and substrate utilization. This review's findings support the hypothesis that the fasted and fed conditions can divergently influence exercise metabolism and performance. Pre-exercise feeding bolsters prolonged aerobic performance, while seminal evidence highlights potential beneficial metabolic adaptations that fasted exercise may induce in peripheral tissues. However, further research is required to fully elucidate the acute and chronic physiological adaptations to fasted vs fed exercise. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Myristoylation Restricts Orientation of the GRASP Domain on Membranes and Promotes Membrane Tethering*

PubMed Central

Heinrich, Frank; Nanda, Hirsh; Goh, Haw Zan; Bachert, Collin; Lösche, Mathias; Linstedt, Adam D.

2014-01-01

The mammalian Golgi reassembly stacking protein (GRASP) proteins are Golgi-localized homotypic membrane tethers that organize Golgi stacks into a long, contiguous ribbon-like structure. It is unknown how GRASPs undergo trans pairing given that cis interactions between the proteins in the plane of the membrane are intrinsically favored. To test the hypothesis that myristoylation of the self-interacting GRASP domain restricts its orientation on the membrane to favor trans pairing, we established an in vitro assay that recapitulates GRASP-dependent membrane tethering and used neutron reflection under similar conditions to determine the orientation of the GRASP domain. In vivo, the membrane association of GRASP proteins is conferred by the simultaneous insertion of an N-terminal myristic acid and binding to a Golgi-associated binding partner. In our assay, the latter contact was replaced using a C-terminal hexa-His moiety, which bound to Ni2+-conjugated lipids incorporated into a substrate-supported bilayer lipid membrane. Nonmyristoylated protein lacked a fixed orientation on the membrane and inefficiently tethered liposomes. In contrast, myristoylated GRASP promoted tethering and exhibited a unique membrane complex. Thus, myristoylation restricts the membrane orientation of the GRASP domain favoring interactions in trans for membrane tethering. PMID:24505136

GRASP55 Senses Glucose Deprivation through O-GlcNAcylation to Promote Autophagosome-Lysosome Fusion.

PubMed

Zhang, Xiaoyan; Wang, Leibin; Lak, Behnam; Li, Jie; Jokitalo, Eija; Wang, Yanzhuang

2018-04-23

The Golgi apparatus is the central hub for protein trafficking and glycosylation in the secretory pathway. However, how the Golgi responds to glucose deprivation is so far unknown. Here, we report that GRASP55, the Golgi stacking protein located in medial- and trans-Golgi cisternae, is O-GlcNAcylated by the O-GlcNAc transferase OGT under growth conditions. Glucose deprivation reduces GRASP55 O-GlcNAcylation. De-O-GlcNAcylated GRASP55 forms puncta outside of the Golgi area, which co-localize with autophagosomes and late endosomes/lysosomes. GRASP55 depletion reduces autophagic flux and results in autophagosome accumulation, while expression of an O-GlcNAcylation-deficient mutant of GRASP55 accelerates autophagic flux. Biochemically, GRASP55 interacts with LC3-II on the autophagosomes and LAMP2 on late endosomes/lysosomes and functions as a bridge between LC3-II and LAMP2 for autophagosome and lysosome fusion; this function is negatively regulated by GRASP55 O-GlcNAcylation. Therefore, GRASP55 senses glucose levels through O-GlcNAcylation and acts as a tether to facilitate autophagosome maturation. Copyright © 2018 Elsevier Inc. All rights reserved.

Haemodynamic dose-response effects of intravenous nisoldipine in coronary artery disease.

PubMed Central

Silke, B; Frais, M A; Muller, P; Verma, S P; Reynolds, G; Taylor, S H

1985-01-01

The circulatory consequences of slow-calcium channel blockade with a new dihydropyridine nisoldipine were evaluated at rest and during exercise-induced angina in 16 patients with angiographically proven coronary artery disease. In 10 patients resting cardiac stroke output (thermodilution) and pulmonary artery occluded pressure were determined following four intravenous nisoldipine injections (cumulative dosage of 1, 2, 4 and 8 micrograms kg-1). The exercise effects of nisoldipine were evaluated by comparing the effects of the 8 micrograms kg-1 cumulative dosage with a control exercise period at the same workload. At rest nisoldipine reduced systemic vascular resistance and mean arterial pressure, and increased heart rate, cardiac and stroke volume indices. During 4 min supine-bicycle exercise nisoldipine reduced systemic mean arterial pressure and vascular resistance; this resulted in augmented cardiac and stroke volume indices at an unchanged pulmonary artery occluded pressure. In six additional patients rest and exercise ejection fractions were measured using a nonimaging nuclear probe. Nisoldipine (4 micrograms kg-1) resulted in a small trend to increase left ventricular rest and exercise ejection fraction. These data demonstrated improved rest and exercise cardiac performance following nisoldipine in patients with severe coronary artery disease. PMID:4091998

Devices for Deviling Classes in Theatre History.

ERIC Educational Resources Information Center

Bryan, George B.

In addition to the use of the lecture-discussion method of teaching theatre history, the author contends that this approach can be augmented by the process of "deviling" (adding spice to) the learning situation. At the University of Vermont, theatre history courses have been taught with a variety of deviling exercises, which include: (1)…

Community Connections to Enhance Undergraduate International Business Education: An Example of Business Consulting Projects

ERIC Educational Resources Information Center

Annavarjula, Madan; Trifts, Jack W.

2012-01-01

Practical project experience as a means of augmenting traditional classroom learning has long been viewed as a value adding curricular exercise. While students participating in the projects gain valuable skills that will enhance their personal marketability, successful projects also benefit the client companies involved and help enhance the image…

CRUX: a Compliant Robotic Upper-Extremity eXosuit for Lightweight, Portable, Multi-DoF Muscular Augmentation

NASA Technical Reports Server (NTRS)

Lessard, Steven; Pansodtee, Pattawong; Robbins, Ash; Baltaxe-Admony, Leya Breanna; Teodorescu, Mircea; Kurniawan,Sri; Agogino, Adrian; Kurniawan, Sri

2017-01-01

Wearable robots can potentially offer their users enhanced stability and strength. These augmentations are ideally designed to actuate harmoniously with the users movements and provide extra force as needed. The creation of such robots, however, is particularly challenging due to the complexity of the underlying human body. In this paper, we present a compliant, robotic exosuit for upper-extremities called CRUX. This exosuit, inspired by tensegrity models of the human arm, features a lightweight (1.3 kg), flexible design for portability. We also show how CRUX maintains full flexibility of the upper-extremities for its users while providing multi- DoF augmentative strength to the major muscles of the arm, as evident by tracking the heart rate of an individual exercising said arm. Exosuits such as CRUX may be useful in physical therapy and in extreme environments where users are expected to exert their bodies to the fullest extent.

Spatiotemporal distribution of location and object effects in reach-to-grasp kinematics

PubMed Central

Rouse, Adam G.

2015-01-01

In reaching to grasp an object, the arm transports the hand to the intended location as the hand shapes to grasp the object. Prior studies that tracked arm endpoint and grip aperture have shown that reaching and grasping, while proceeding in parallel, are interdependent to some degree. Other studies of reaching and grasping that have examined the joint angles of all five digits as the hand shapes to grasp various objects have not tracked the joint angles of the arm as well. We, therefore, examined 22 joint angles from the shoulder to the five digits as monkeys reached, grasped, and manipulated in a task that dissociated location and object. We quantified the extent to which each angle varied depending on location, on object, and on their interaction, all as a function of time. Although joint angles varied depending on both location and object beginning early in the movement, an early phase of location effects in joint angles from the shoulder to the digits was followed by a later phase in which object effects predominated at all joint angles distal to the shoulder. Interaction effects were relatively small throughout the reach-to-grasp. Whereas reach trajectory was influenced substantially by the object, grasp shape was comparatively invariant to location. Our observations suggest that neural control of reach-to-grasp may occur largely in two sequential phases: the first determining the location to which the arm transports the hand, and the second shaping the entire upper extremity to grasp and manipulate the object. PMID:26445870

Examining physiotherapist use of structured aerobic exercise testing to decrease barriers to aerobic exercise.

PubMed

Foster B Sc, Evan; Fraser, Julia E; Inness PhD, Elizabeth L; Munce, Sarah; Biasin, Louis; Poon, Vivien; Bayley, Mark

2018-04-03

To determine the frequency of physiotherapist-administered aerobic exercise testing/training, the proportion of physiotherapists who administer this testing/training, and the barriers that currently exist across different practice environments. A secondary objective is to identify the learning needs of physiotherapists for the development of an education curriculum in aerobic exercise testing and training with electrocardiograph (ECG) administration and interpretation. National, cross-sectional survey. Registered physiotherapists practicing in Canada. Out of 137 participants, most (75%) physiotherapists prescribed aerobic exercise on a regular basis (weekly); however, 65% had never conducted an aerobic exercise test. There were no significant differences in frequency of aerobic exercise testing across different practice environments or across years of physiotherapy experience. Physiotherapists perceived the main barriers to aerobic exercise testing as being a lack of equipment/space (78%), time (65%), and knowledge (56%). Although most (82%) were uncomfortable administering 12-lead ECG-monitored aerobic exercise tests, 60% stated they would be interested in learning more about ECG interpretation. This study found that physiotherapists are regularly implementing aerobic exercise. This exercise was infrequently guided by formal aerobic exercise testing, which could increase access to safe and effective exercise within the optimal aerobic training zone. As well, this could facilitate training in patients with cardiovascular diagnoses that require additional testing for medical clearance. Increased ECG training and access to equipment for physiotherapists may augment pre-screening aerobic exercise testing. This training should include learning the key arrhythmias for aerobic exercise test termination as defined by the American College of Sports Medicine.

Inhibition of KATP channel activity augments baroreflex-mediated vasoconstriction in exercising human skeletal muscle

PubMed Central

Keller, David Melvin; Ogoh, Shigehiko; Greene, Shane; Olivencia-Yurvati, A; Raven, Peter B

2004-01-01

In the present investigation we examined the role of ATP-sensitive potassium (KATP) channel activity in modulating carotid baroreflex (CBR)-induced vasoconstriction in the vasculature of the leg. The CBR control of mean arterial pressure (MAP) and leg vascular conductance (LVC) was determined in seven subjects (25 ± 1 years, mean ± s.e.m.) using the variable-pressure neck collar technique at rest and during one-legged knee extension exercise. The oral ingestion of glyburide (5 mg) did not change mean arterial pressure (MAP) at rest (86 versus 89 mmHg, P > 0.05), but did appear to increase MAP during exercise (87 versus 92 mmHg, P = 0.053). However, the CBR–MAP function curves were similar at rest before and after glyburide ingestion. The CBR-mediated decrease in LVC observed at rest (∼39%) was attenuated during exercise in the exercising leg (∼15%, P < 0.05). Oral glyburide ingestion partially restored CBR-mediated vasoconstriction in the exercising leg (∼40% restoration, P < 0.05) compared to control exercise. These findings indicate that KATP channel activity modulates sympathetic vasoconstriction in humans and may prove to be an important mechanism by which functional sympatholysis operates in humans during exercise. PMID:15345750

Physical Exercise As Stabilizer For Alzheimer'S Disease Cognitive Decline: Current Status.

PubMed

Machado, Sergio; Filho, Alberto Souza de Sá; Wilbert, Matheus; Barbieri, Gabriela; Almeida, Victor; Gurgel, Alexandre; Rosa, Charles V; Lins, Victor; Paixão, Alexandre; Santana, Kamila; Ramos, Gabriel; Neto, Geraldo Maranhão; Paes, Flá; Rocha, Nuno; Murillo-Rodriguez, Eric

2017-01-01

Mental health decline is one of the main responsible factors for augments in health care costs, and diagnosis of Alzheimer's disease (AD). Some studies stated physical exercise is useful for reduction in cognitive decline and AD. Moreover, a recent review argued that evidence are scarce due to few studies published and lack of configuration information of exercise protocol, such as intensity and duration of exercise, number of sessions and other relevant data, to allow appropriate assessment. Here, we discussed the possible confounders or factors responsible for these differences and possible neurophysiological mechanisms. Most studies revealed a possible positive association between physical exercise and cognitive assessments. There are inconsistencies in studies design responsible for varying use of cognitive assessments and different assessments of fitness. However, these studies do not fail to provide evidence about the benefits of exercise, but fail to make it possible because of the lack of dose-response information in AD patients. Physical exercise of moderate intensity should be considered as standard recommendation to reduce cognitive decline, probably due to the improvement in neurodegenerative mechanisms, and the increase in neuroplastic and neuroprotective neurotrophic factors. Therefore, it is suggested that physical exercise is an important neuroprotective modulator, bringing significant control of the disease and amplifying brain functions.

Neural coordination during reach-to-grasp

PubMed Central

Vaidya, Mukta; Kording, Konrad; Saleh, Maryam; Takahashi, Kazutaka

2015-01-01

When reaching to grasp, we coordinate how we preshape the hand with how we move it. To ask how motor cortical neurons participate in this coordination, we examined the interactions between reach- and grasp-related neuronal ensembles while monkeys reached to grasp a variety of different objects in different locations. By describing the dynamics of these two ensembles as trajectories in a low-dimensional state space, we examined their coupling in time. We found evidence for temporal compensation across many different reach-to-grasp conditions such that if one neural trajectory led in time the other tended to catch up, reducing the asynchrony between the trajectories. Granger causality revealed bidirectional interactions between reach and grasp neural trajectories beyond that which could be attributed to the joint kinematics that were consistently stronger in the grasp-to-reach direction. Characterizing cortical coordination dynamics provides a new framework for understanding the functional interactions between neural populations. PMID:26224773

Grasp posture alters visual processing biases near the hands

PubMed Central

Thomas, Laura E.

2015-01-01

Observers experience biases in visual processing for objects within easy reach of their hands that may assist them in evaluating items that are candidates for action. I investigated the hypothesis that hand postures affording different types of actions differentially bias vision. Across three experiments, participants performed global motion detection and global form perception tasks while their hands were positioned a) near the display in a posture affording a power grasp, b) near the display in a posture affording a precision grasp, or c) in their laps. Although the power grasp posture facilitated performance on the motion task, the precision grasp posture instead facilitated performance on the form task. These results suggest that the visual system weights processing based on an observer’s current affordances for specific actions: fast and forceful power grasps enhance temporal sensitivity, while detail-oriented precision grasps enhance spatial sensitivity. PMID:25862545

GRASP1 regulates synaptic plasticity and learning through endosomal recycling of AMPA receptors

PubMed Central

Chiu, Shu-Ling; Diering, Graham Hugh; Ye, Bing; Takamiya, Kogo; Chen, Chih-Ming; Jiang, Yuwu; Niranjan, Tejasvi; Schwartz, Charles E.; Wang, Tao; Huganir, Richard L.

2017-01-01

Summary Learning depends on experience-dependent modification of synaptic efficacy and neuronal connectivity in the brain. We provide direct evidence for physiological roles of the recycling endosome protein GRASP1 in glutamatergic synapse function and animal behavior. Mice lacking GRASP1 showed abnormal excitatory synapse number, synaptic plasticity and hippocampal-dependent learning and memory due to a failure in learning-induced synaptic AMPAR incorporation. We identified two GRASP1 point mutations from intellectual disability (ID) patients that showed convergent disruptive effects on AMPAR recycling and glutamate uncaging-induced structural and functional plasticity. Wild-type GRASP1, but not ID mutants, rescues spine loss in hippocampal CA1 neurons of Grasp1 knockout mice. Together, these results demonstrate a requirement for normal recycling endosome function in AMPAR-dependent synaptic function and neuronal connectivity in vivo, and suggest a potential role for GRASP1 in the pathophysiology of human cognitive disorders. PMID:28285821

A novel algorithm for fast grasping of unknown objects using C-shape configuration

NASA Astrophysics Data System (ADS)

Lei, Qujiang; Chen, Guangming; Meijer, Jonathan; Wisse, Martijn

2018-02-01

Increasing grasping efficiency is very important for the robots to grasp unknown objects especially subjected to unfamiliar environments. To achieve this, a new algorithm is proposed based on the C-shape configuration. Specifically, the geometric model of the used under-actuated gripper is approximated as a C-shape. To obtain an appropriate graspable position, this C-shape configuration is applied to fit geometric model of an unknown object. The geometric model of unknown object is constructed by using a single-view partial point cloud. To examine the algorithm using simulations, a comparison of the commonly used motion planners is made. The motion planner with the highest number of solved runs, lowest computing time and the shortest path length is chosen to execute grasps found by this grasping algorithm. The simulation results demonstrate that excellent grasping efficiency is achieved by adopting our algorithm. To validate this algorithm, experiment tests are carried out using a UR5 robot arm and an under-actuated gripper. The experimental results show that steady grasping actions are obtained. Hence, this research provides a novel algorithm for fast grasping of unknown objects.

Grasping trajectories in a virtual environment adhere to Weber's law.

PubMed

Ozana, Aviad; Berman, Sigal; Ganel, Tzvi

2018-06-01

Virtual-reality and telerobotic devices simulate local motor control of virtual objects within computerized environments. Here, we explored grasping kinematics within a virtual environment and tested whether, as in normal 3D grasping, trajectories in the virtual environment are performed analytically, violating Weber's law with respect to object's size. Participants were asked to grasp a series of 2D objects using a haptic system, which projected their movements to a virtual space presented on a computer screen. The apparatus also provided object-specific haptic information upon "touching" the edges of the virtual targets. The results showed that grasping movements performed within the virtual environment did not produce the typical analytical trajectory pattern obtained during 3D grasping. Unlike as in 3D grasping, grasping trajectories in the virtual environment adhered to Weber's law, which indicates relative resolution in size processing. In addition, the trajectory patterns differed from typical trajectories obtained during 3D grasping, with longer times to complete the movement, and with maximum grip apertures appearing relatively early in the movement. The results suggest that grasping movements within a virtual environment could differ from those performed in real space, and are subjected to irrelevant effects of perceptual information. Such atypical pattern of visuomotor control may be mediated by the lack of complete transparency between the interface and the virtual environment in terms of the provided visual and haptic feedback. Possible implications of the findings to movement control within robotic and virtual environments are further discussed.

Haptically Guided Grasping. fMRI Shows Right-Hemisphere Parietal Stimulus Encoding, and Bilateral Dorso-Ventral Parietal Gradients of Object- and Action-Related Processing during Grasp Execution

PubMed Central

Marangon, Mattia; Kubiak, Agnieszka; Króliczak, Gregory

2016-01-01

The neural bases of haptically-guided grasp planning and execution are largely unknown, especially for stimuli having no visual representations. Therefore, we used functional magnetic resonance imaging (fMRI) to monitor brain activity during haptic exploration of novel 3D complex objects, subsequent grasp planning, and the execution of the pre-planned grasps. Haptic object exploration, involving extraction of shape, orientation, and length of the to-be-grasped targets, was associated with the fronto-parietal, temporo-occipital, and insular cortex activity. Yet, only the anterior divisions of the posterior parietal cortex (PPC) of the right hemisphere were significantly more engaged in exploration of complex objects (vs. simple control disks). None of these regions were re-recruited during the planning phase. Even more surprisingly, the left-hemisphere intraparietal, temporal, and occipital areas that were significantly invoked for grasp planning did not show sensitivity to object features. Finally, grasp execution, involving the re-recruitment of the critical right-hemisphere PPC clusters, was also significantly associated with two kinds of bilateral parieto-frontal processes. The first represents transformations of grasp-relevant target features and is linked to the dorso-dorsal (lateral and medial) parieto-frontal networks. The second monitors grasp kinematics and belongs to the ventro-dorsal networks. Indeed, signal modulations associated with these distinct functions follow dorso-ventral gradients, with left aIPS showing significant sensitivity to both target features and the characteristics of the required grasp. Thus, our results from the haptic domain are consistent with the notion that the parietal processing for action guidance reflects primarily transformations from object-related to effector-related coding, and these mechanisms are rather independent of sensory input modality. PMID:26779002

Relevance of grasp types to assess functionality for personal autonomy.

PubMed

Gracia-Ibáñez, Verónica; Sancho-Bru, Joaquin L; Vergara, Margarita

Cross-sectional research design. Current assessment of hand function is not focused on evaluating the real abilities required for autonomy. To quantify the relevance of grasp types for autonomy to guide hand recovery and its assessment. Representative tasks of the International Classification of Functioning, Disability and Health activities in which the hands are directly involved were recorded. The videos were analyzed to identify the grasps used with each hand, and their relevance for autonomy was determined by weighting time with the frequency of appearance of each activity in disability and dependency scales. Relevance is provided globally and distinguished by hand (right-left) and bimanual function. Significant differences in relevance are also checked. The most relevant grasps are pad-to-pad pinch (31.9%), lumbrical (15.4%), cylindrical (12%), and special pinch (7.3%) together with the nonprehensile (18.6%) use of the hand. Lumbrical grasp has higher relevance for the left hand (19.9% vs 12%) while cylindrical grasp for the right hand (15.3% vs 7.7%). Relevancies are also different depending on bimanual function. Different relative importance was obtained when considering dependency vs disability scales. Pad-to-pad pinch and nonprehensile grasp are the most relevant grasps for both hands, whereas lumbrical grasp is more relevant for the left hand and cylindrical grasp for the right one. The most significant difference in bimanual function refers to pad-to-pad pinch (more relevant for unimanual actions of the left hand and bimanual actions of the right). The relative importance of each grasp type for autonomy and the differences observed between hand and bimanual action should be used in medical and physical decision-making. N/A. Copyright © 2017 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Haptically Guided Grasping. fMRI Shows Right-Hemisphere Parietal Stimulus Encoding, and Bilateral Dorso-Ventral Parietal Gradients of Object- and Action-Related Processing during Grasp Execution.

PubMed

Marangon, Mattia; Kubiak, Agnieszka; Króliczak, Gregory

2015-01-01

The neural bases of haptically-guided grasp planning and execution are largely unknown, especially for stimuli having no visual representations. Therefore, we used functional magnetic resonance imaging (fMRI) to monitor brain activity during haptic exploration of novel 3D complex objects, subsequent grasp planning, and the execution of the pre-planned grasps. Haptic object exploration, involving extraction of shape, orientation, and length of the to-be-grasped targets, was associated with the fronto-parietal, temporo-occipital, and insular cortex activity. Yet, only the anterior divisions of the posterior parietal cortex (PPC) of the right hemisphere were significantly more engaged in exploration of complex objects (vs. simple control disks). None of these regions were re-recruited during the planning phase. Even more surprisingly, the left-hemisphere intraparietal, temporal, and occipital areas that were significantly invoked for grasp planning did not show sensitivity to object features. Finally, grasp execution, involving the re-recruitment of the critical right-hemisphere PPC clusters, was also significantly associated with two kinds of bilateral parieto-frontal processes. The first represents transformations of grasp-relevant target features and is linked to the dorso-dorsal (lateral and medial) parieto-frontal networks. The second monitors grasp kinematics and belongs to the ventro-dorsal networks. Indeed, signal modulations associated with these distinct functions follow dorso-ventral gradients, with left aIPS showing significant sensitivity to both target features and the characteristics of the required grasp. Thus, our results from the haptic domain are consistent with the notion that the parietal processing for action guidance reflects primarily transformations from object-related to effector-related coding, and these mechanisms are rather independent of sensory input modality.

Grasp-specific motor resonance is influenced by the visibility of the observed actor.

PubMed

Bunday, Karen L; Lemon, Roger N; Kilner, James M; Davare, Marco; Orban, Guy A

2016-11-01

Motor resonance is the modulation of M1 corticospinal excitability induced by observation of others' actions. Recent brain imaging studies have revealed that viewing videos of grasping actions led to a differential activation of the ventral premotor cortex depending on whether the entire person is viewed versus only their disembodied hand. Here we used transcranial magnetic stimulation (TMS) to examine motor evoked potentials (MEPs) in the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) during observation of videos or static images in which a whole person or merely the hand was seen reaching and grasping a peanut (precision grip) or an apple (whole hand grasp). Participants were presented with six visual conditions in which visual stimuli (video vs static image), view (whole person vs hand) and grasp (precision grip vs whole hand grasp) were varied in a 2 × 2 × 2 factorial design. Observing videos, but not static images, of a hand grasping different objects resulted in a grasp-specific interaction, such that FDI and ADM MEPs were differentially modulated depending on the type of grasp being observed (precision grip vs whole hand grasp). This interaction was present when observing the hand acting, but not when observing the whole person acting. Additional experiments revealed that these results were unlikely to be due to the relative size of the hand being observed. Our results suggest that observation of videos rather than static images is critical for motor resonance. Importantly, observing the whole person performing the action abolished the grasp-specific effect, which could be due to a variety of PMv inputs converging on M1. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Assessment of input-output properties and control of neuroprosthetic hand grasp.

PubMed

Hines, A E; Owens, N E; Crago, P E

1992-06-01

Three tests have been developed to evaluate rapidly and quantitatively the input-output properties and patient control of neuroprosthetic hand grasp. Each test utilizes a visual pursuit tracking task during which the subject controls the grasp force and grasp opening (position) of the hand. The first test characterizes the static input-output properties of the hand grasp, where the input is a slowly changing patient generated command signal and the outputs are grasp force and grasp opening. Nonlinearities and inappropriate slopes have been documented in these relationships, and in some instances the need for system returning has been indicated. For each subject larger grasp forces were produced when grasping larger objects, and for some subjects the shapes of the relationships also varied with object size. The second test quantifies the ability of the subject to control the hand grasp outputs while tracking steps and ramps. Neuroprosthesis users had rms errors two to three times larger when tracking steps versus ramps, and had rms errors four to five times larger than normals when tracking ramps. The third test provides an estimate of the frequency response of the hand grasp system dynamics, from input and output data collected during a random tracking task. Transfer functions were estimated by spectral analysis after removal of the static input-output nonlinearities measured in the first test. The dynamics had low-pass filter characteristics with 3 dB cutoff frequencies from 1.0 to 1.4 Hz. The tests developed in this study provide a rapid evaluation of both the system and the user. They provide information to 1) help interpret subject performance of functional tasks, 2) evaluate the efficacy of system features such as closed-loop control, and 3) screen the neuroprosthesis to indicate the need for retuning.

Ambient temperature influences the neural benefits of exercise.

PubMed

Maynard, Mark E; Chung, Chasity; Comer, Ashley; Nelson, Katharine; Tran, Jamie; Werries, Nadja; Barton, Emily A; Spinetta, Michael; Leasure, J Leigh

2016-02-15

Many of the neural benefits of exercise require weeks to manifest. It would be useful to accelerate onset of exercise-driven plastic changes, such as increased hippocampal neurogenesis. Exercise represents a significant challenge to the brain because it produces heat, but brain temperature does not rise during exercise in the cold. This study tested the hypothesis that exercise in cold ambient temperature would stimulate hippocampal neurogenesis more than exercise in room or hot conditions. Adult female rats had exercise access 2h per day for 5 days at either room (20 °C), cold (4.5 °C) or hot (37.5 °C) temperature. To label dividing hippocampal precursor cells, animals received daily injections of BrdU. Brains were immunohistochemically processed for dividing cells (Ki67+), surviving cells (BrdU+) and new neurons (doublecortin, DCX) in the hippocampal dentate gyrus. Animals exercising at room temperature ran significantly farther than animals exercising in cold or hot conditions (room 1490 ± 400 m; cold 440 ± 102 m; hot 291 ± 56 m). We therefore analyzed the number of Ki67+, BrdU+ and DCX+ cells normalized for shortest distance run. Contrary to our hypothesis, exercise in either cold or hot conditions generated significantly more Ki67+, BrdU+ and DCX+ cells compared to exercise at room temperature. Thus, a limited amount of running in either cold or hot ambient conditions generates more new cells than a much greater distance run at room temperature. Taken together, our results suggest a simple means by which to augment exercise effects, yet minimize exercise time. Copyright © 2015 Elsevier B.V. All rights reserved.

Chronic disease self-management and exercise in COPD as pulmonary rehabilitation: a randomized controlled trial.

PubMed

Cameron-Tucker, Helen L; Wood-Baker, Richard; Owen, Christine; Joseph, Lyn; Walters, E Haydn

2014-01-01

Both exercise and self-management are advocated in pulmonary rehabilitation for people with chronic obstructive pulmonary disease (COPD). The widely used 6-week, group-based Chronic Disease Self-Management Program (CDSMP) increases self-reported exercise, despite supervised exercise not being a program component. This has been little explored in COPD. Whether adding supervised exercise to the CDSMP would add benefit is unknown. We investigated the CDSMP in COPD, with and without a formal supervised exercise component, to address this question. Adult outpatients with COPD were randomized to the CDSMP with or without one hour of weekly supervised exercise over 6 weeks. The primary outcome measure was 6-minute walk test distance (6MWD). Secondary outcomes included self-reported exercise, exercise stage of change, exercise self-efficacy, breathlessness, quality of life, and self-management behaviors. Within- and between-group differences were analyzed on an intention-to-treat basis. Of 84 subjects recruited, 15 withdrew. 6MWD increased similarly in both groups: CDSMP-plus-exercise (intervention group) by 18.6±46.2 m; CDSMP-alone (control group) by 20.0±46.2 m. There was no significant difference for any secondary outcome. The CDSMP produced à small statistically significant increase in 6MWD. The addition of a single supervised exercise session did not further increase exercise capacity. Our findings confirm the efficacy of a behaviorally based intervention in COPD, but this would seem to be less than expected from conventional exercise-based pulmonary rehabilitation, raising the question of how, if at all, the small gains observed in this study may be augmented.

Multidigit force control during unconstrained grasping in response to object perturbations

PubMed Central

Haschke, Robert; Ritter, Helge; Santello, Marco; Ernst, Marc O.

2017-01-01

Because of the complex anatomy of the human hand, in the absence of external constraints, a large number of postures and force combinations can be used to attain a stable grasp. Motor synergies provide a viable strategy to solve this problem of motor redundancy. In this study, we exploited the technical advantages of an innovative sensorized object to study unconstrained hand grasping within the theoretical framework of motor synergies. Participants were required to grasp, lift, and hold the sensorized object. During the holding phase, we repetitively applied external disturbance forces and torques and recorded the spatiotemporal distribution of grip forces produced by each digit. We found that the time to reach the maximum grip force during each perturbation was roughly equal across fingers, consistent with a synchronous, synergistic stiffening across digits. We further evaluated this hypothesis by comparing the force distribution of human grasping vs. robotic grasping, where the control strategy was set by the experimenter. We controlled the global hand stiffness of the robotic hand and found that this control algorithm produced a force pattern qualitatively similar to human grasping performance. Our results suggest that the nervous system uses a default whole hand synergistic control to maintain a stable grasp regardless of the number of digits involved in the task, their position on the objects, and the type and frequency of external perturbations. NEW & NOTEWORTHY We studied hand grasping using a sensorized object allowing unconstrained finger placement. During object perturbation, the time to reach the peak force was roughly equal across fingers, consistently with a synergistic stiffening across fingers. Force distribution of a robotic grasping hand, where the control algorithm is based on global hand stiffness, was qualitatively similar to human grasping. This suggests that the central nervous system uses a default whole hand synergistic control to maintain a stable grasp. PMID:28228582

Gaze anchoring guides real but not pantomime reach-to-grasp: support for the action-perception theory.

PubMed

Kuntz, Jessica R; Karl, Jenni M; Doan, Jon B; Whishaw, Ian Q

2018-04-01

Reach-to-grasp movements feature the integration of a reach directed by the extrinsic (location) features of a target and a grasp directed by the intrinsic (size, shape) features of a target. The action-perception theory suggests that integration and scaling of a reach-to-grasp movement, including its trajectory and the concurrent digit shaping, are features that depend upon online action pathways of the dorsal visuomotor stream. Scaling is much less accurate for a pantomime reach-to-grasp movement, a pretend reach with the target object absent. Thus, the action-perception theory proposes that pantomime movement is mediated by perceptual pathways of the ventral visuomotor stream. A distinguishing visual feature of a real reach-to-grasp movement is gaze anchoring, in which a participant visually fixates the target throughout the reach and disengages, often by blinking or looking away/averting the head, at about the time that the target is grasped. The present study examined whether gaze anchoring is associated with pantomime reaching. The eye and hand movements of participants were recorded as they reached for a ball of one of three sizes, located on a pedestal at arms' length, or pantomimed the same reach with the ball and pedestal absent. The kinematic measures for real reach-to-grasp movements were coupled to the location and size of the target, whereas the kinematic measures for pantomime reach-to-grasp, although grossly reflecting target features, were significantly altered. Gaze anchoring was also tightly coupled to the target for real reach-to-grasp movements, but there was no systematic focus for gaze, either in relation with the virtual target, the previous location of the target, or the participant's reaching hand, for pantomime reach-to-grasp. The presence of gaze anchoring during real vs. its absence in pantomime reach-to-grasp supports the action-perception theory that real, but not pantomime, reaches are online visuomotor actions and is discussed in relation with the neural control of real and pantomime reach-to-grasp movements.

Neuronal Correlates of Functional Coupling between Reach- and Grasp-Related Components of Muscle Activity

PubMed Central

Geed, Shashwati; McCurdy, Martha L.; van Kan, Peter L. E.

2017-01-01

Coordinated reach-to-grasp movements require precise spatiotemporal synchrony between proximal forelimb muscles (shoulder, elbow) that transport the hand toward a target during reach, and distal muscles (wrist, digit) that simultaneously preshape and orient the hand for grasp. The precise mechanisms through which the redundant neuromuscular circuitry coordinates reach with grasp, however, remain unclear. Recently, Geed and Van Kan (2016) demonstrated, using exploratory factor analysis (EFA), that limited numbers of global, template-like transport/preshape- and grasp-related muscle components underlie the complexity and variability of intramuscular electromyograms (EMGs) of up to 21 distal and proximal muscles recorded while monkeys performed reach-to-grasp tasks. Importantly, transport/preshape- and grasp-related muscle components showed invariant spatiotemporal coupling, which provides a potential mechanism for coordinating forelimb muscles during reach-to-grasp movements. In the present study, we tested whether ensemble discharges of forelimb neurons in the cerebellar nucleus interpositus (NI) and its target, the magnocellular red nucleus (RNm), a source of rubrospinal fibers, function as neuronal correlates of the transport/preshape- and grasp-related muscle components we identified. EFA applied to single-unit discharges of populations of NI and RNm neurons recorded while the same monkeys that were used previously performed the same reach-to-grasp tasks, revealed neuronal components in the ensemble discharges of both NI and RNm neuronal populations with characteristics broadly similar to muscle components. Subsets of NI and RNm neuronal components were strongly and significantly crosscorrelated with subsets of muscle components, suggesting that similar functional units of reach-to-grasp behavior are expressed by NI and RNm neuronal populations and forelimb muscles. Importantly, like transport/preshape- and grasp-related muscle components, their NI and RNm neuronal correlates showed invariant spatiotemporal coupling. Clinical and lesion studies have reported disruption of coupling between reach and grasp following cerebellar damage; the present results expand on those studies by identifying a neuronal mechanism that may underlie cerebellar contributions to spatiotemporal coordination of distal and proximal limb muscles during reaching to grasp. We conclude that finding similar functional units of behavior expressed at multiple levels of information processing along interposito-rubrospinal pathways and forelimb muscles supports the hypothesis that functionally related populations of NI and RNm neurons act synergistically in the control of complex coordinated motor behaviors. PMID:28270752

Spatiotemporal Distribution of Location and Object Effects in Primary Motor Cortex Neurons during Reach-to-Grasp

PubMed Central

Rouse, Adam G.

2016-01-01

Reaching and grasping typically are considered to be spatially separate processes that proceed concurrently in the arm and the hand, respectively. The proximal representation in the primary motor cortex (M1) controls the arm for reaching, while the distal representation controls the hand for grasping. Many studies of M1 activity therefore have focused either on reaching to various locations without grasping different objects, or else on grasping different objects all at the same location. Here, we recorded M1 neurons in the anterior bank and lip of the central sulcus as monkeys performed more naturalistic movements, reaching toward, grasping, and manipulating four different objects in up to eight different locations. We quantified the extent to which variation in firing rates depended on location, on object, and on their interaction—all as a function of time. Activity proceeded largely in two sequential phases: the first related predominantly to the location to which the upper extremity reached, and the second related to the object about to be grasped. Both phases involved activity distributed widely throughout the sampled territory, spanning both the proximal and the distal upper extremity representation in caudal M1. Our findings indicate that naturalistic reaching and grasping, rather than being spatially segregated processes that proceed concurrently, each are spatially distributed processes controlled by caudal M1 in large part sequentially. Rather than neuromuscular processes separated in space but not time, reaching and grasping are separated more in time than in space. SIGNIFICANCE STATEMENT Reaching and grasping typically are viewed as processes that proceed concurrently in the arm and hand, respectively. The arm region in the primary motor cortex (M1) is assumed to control reaching, while the hand region controls grasping. During naturalistic reach–grasp–manipulate movements, we found, however, that neuron activity proceeds largely in two sequential phases, each spanning both arm and hand representations in M1. The first phase is related predominantly to the reach location, and the second is related to the object about to be grasped. Our findings indicate that reaching and grasping are successive aspects of a single movement. Initially the arm and the hand both are projected toward the object's location, and later both are shaped to grasp and manipulate. PMID:27733614

Are gender differences in upper-body power generated by elite cross-country skiers augmented by increasing the intensity of exercise?

PubMed

Hegge, Ann Magdalen; Myhre, Kenneth; Welde, Boye; Holmberg, Hans-Christer; Sandbakk, Øyvind

2015-01-01

In the current study, we evaluated the impact of exercise intensity on gender differences in upper-body poling among cross-country skiers, as well as the associated differences in aerobic capacity, maximal strength, body composition, technique and extent of training. Eight male and eight female elite skiers, gender-matched for level of performance by FIS points, carried out a 4-min submaximal, and a 3-min and 30-sec maximal all-out test of isolated upper-body double poling on a Concept2 ski ergometer. Maximal upper-body power and strength (1RM) were determined with a pull-down exercise. In addition, body composition was assessed with a DXA scan and training during the previous six months quantified from diaries. Relative to the corresponding female values (defined as 100%), the power output produced by the men was 88%, 95% and 108% higher during the submaximal, 3-min and 30-sec tests, respectively, and peak power in the pull-down strength exercise was 118% higher (all P<0.001). During the ergometer tests the work performed per cycle by the men was 97%, 102% and 91% greater, respectively, and the men elevated their cycle rate to a greater extent at higher intensities (both P<0.01). Furthermore, men had a 61% higher VO2peak, 58% higher 1RM, relatively larger upper-body mass (61% vs 56%) and reported considerably more upper-body strength and endurance training (all P<0.05). In conclusion, gender differences in upper-body power among cross-country skiers augmented as the intensity of exercise increased. The gender differences observed here are greater than those reported previously for both lower- and whole-body sports and coincided with greater peak aerobic capacity and maximal upper-body strength, relatively more muscle mass in the upper-body, and more extensive training of upper-body strength and endurance among the male skiers.

Are Gender Differences in Upper-Body Power Generated by Elite Cross-Country Skiers Augmented by Increasing the Intensity of Exercise?

PubMed Central

Hegge, Ann Magdalen; Myhre, Kenneth; Welde, Boye; Holmberg, Hans-Christer; Sandbakk, Øyvind

2015-01-01

In the current study, we evaluated the impact of exercise intensity on gender differences in upper-body poling among cross-country skiers, as well as the associated differences in aerobic capacity, maximal strength, body composition, technique and extent of training. Eight male and eight female elite skiers, gender-matched for level of performance by FIS points, carried out a 4-min submaximal, and a 3-min and 30-sec maximal all-out test of isolated upper-body double poling on a Concept2 ski ergometer. Maximal upper-body power and strength (1RM) were determined with a pull-down exercise. In addition, body composition was assessed with a DXA scan and training during the previous six months quantified from diaries. Relative to the corresponding female values (defined as 100%), the power output produced by the men was 88%, 95% and 108% higher during the submaximal, 3-min and 30-sec tests, respectively, and peak power in the pull-down strength exercise was 118% higher (all P<0.001). During the ergometer tests the work performed per cycle by the men was 97%, 102% and 91% greater, respectively, and the men elevated their cycle rate to a greater extent at higher intensities (both P<0.01). Furthermore, men had a 61% higher VO2peak, 58% higher 1RM, relatively larger upper-body mass (61% vs 56%) and reported considerably more upper-body strength and endurance training (all P<0.05). In conclusion, gender differences in upper-body power among cross-country skiers augmented as the intensity of exercise increased. The gender differences observed here are greater than those reported previously for both lower- and whole-body sports and coincided with greater peak aerobic capacity and maximal upper-body strength, relatively more muscle mass in the upper-body, and more extensive training of upper-body strength and endurance among the male skiers. PMID:26000713

Reversible grasp reflexes in normal pressure hydrocephalus.

PubMed

Thomas, Rhys H; Bennetto, Luke; Silva, Mark T

2009-05-01

We present two cases of normal pressure hydrocephalus in combination with grasp reflexes. In both cases the grasp reflexes disappeared following high volume cerebrospinal fluid removal. In one of the cases the grasp reflexes returned over a period of weeks but again resolved following definitive cerebrospinal fluid shunting surgery, and remained absent until final follow up at 9 months. We hypothesise that resolving grasp reflexes following high volume CSF removal has both diagnostic and prognostic value in normal pressure hydrocephalus, encouraging larger studies on the relevance of primitive reflexes in NPH.

Grasp Assist Device with Automatic Mode Control Logic

NASA Technical Reports Server (NTRS)

Laske, Evan (Inventor); Davis, Donald R. (Inventor); Ihrke, Chris A. (Inventor)

2018-01-01

A system includes a glove, sensors, actuator assemblies, and controller. The sensors include load sensors which measure an actual grasping force and attitude sensors which determine a glove attitude. The actuator assembly provides a grasp assist force to the glove. Respective locations of work cells in the work environment and permitted work tasks for each work cell are programmed into the controller. The controller detects the glove location and attitude. A work task is selected by the controller for the location. The controller calculates a required grasp assist force using measured actual grasping forces from the load sensors. The required grasp assist force is applied via the glove using the actuator assembly to thereby assist the operator in performing the identified work task.

Autonomous Object Manipulation Using a Soft Planar Grasping Manipulator

PubMed Central

Katzschmann, Robert K.; Marchese, Andrew D.

2015-01-01

Abstract This article presents the development of an autonomous motion planning algorithm for a soft planar grasping manipulator capable of grasp-and-place operations by encapsulation with uncertainty in the position and shape of the object. The end effector of the soft manipulator is fabricated in one piece without weakening seams using lost-wax casting instead of the commonly used multilayer lamination process. The soft manipulation system can grasp randomly positioned objects within its reachable envelope and move them to a desired location without human intervention. The autonomous planning system leverages the compliance and continuum bending of the soft grasping manipulator to achieve repeatable grasps in the presence of uncertainty. A suite of experiments is presented that demonstrates the system's capabilities. PMID:27625916

Exercise-induced brachial artery vasodilation: effects of antioxidants and exercise training in elderly men

PubMed Central

Donato, Anthony J.; Uberoi, Abhimanyu; Bailey, Damian M.; Walter Wray, D.

2010-01-01

Aging, vascular function, and exercise are thought to have a common link in oxidative stress. Of the 28 subjects studied (young, 26 ± 2 yr; old, 71 ± 6 yr), 12 took part in a study to validate an antioxidant cocktail (AOC: vitamins C, E, and α-lipoic acid), while the remaining 8 young and 8 old subjects performed submaximal forearm handgrip exercise with placebo or AOC. Old subjects repeated forearm exercise with placebo or AOC following knee-extensor (KE) exercise training. Brachial arterial diameter and blood velocity (Doppler ultrasound) were measured at rest and during exercise. During handgrip exercise, brachial artery vasodilation in the old subjects was attenuated compared with that in young subjects following placebo (maximum = ∼3.0 and ∼6.0%, respectively). In contrast to the previously documented attenuation in exercise-induced brachial artery vasodilation in the young group with AOC, in the old subjects the AOC restored vasodilation (maximum = ∼7.0%) to match the young. KE training also improved exercise-induced brachial artery vasodilation. However, in the trained state, AOC administration no longer augmented brachial artery vasodilation in the elderly, but rather attenuated it. These data reveal an age-related pro-/antioxidant imbalance that impacts vascular function and show that exercise training is capable of restoring equilibrium such that vascular function is improved and the AOC-mediated reduction in free radicals now negatively impacts brachial artery vasodilation, as seen in the young. PMID:19966056

A perturbation-based balance training program for older adults: study protocol for a randomised controlled trial

PubMed Central

Mansfield, Avril; Peters, Amy L; Liu, Barbara A; Maki, Brian E

2007-01-01

Background Previous research investigating exercise as a means of falls prevention in older adults has shown mixed results. Lack of specificity of the intervention may be an important factor contributing to negative results. Change-in-support (CIS) balance reactions, which involve very rapid stepping or grasping movements of the limbs, play a critical role in preventing falls; hence, a training program that improves ability to execute effective CIS reactions could potentially have a profound effect in reducing risk of falling. This paper describes: 1) the development of a perturbation-based balance training program that targets specific previously-reported age-related impairments in CIS reactions, and 2) a study protocol to evaluate the efficacy of this new training program. Methods/Design The training program involves use of unpredictable, multi-directional moving-platform perturbations to evoke stepping and grasping reactions. Perturbation magnitude is gradually increased over the course of the 6-week program, and concurrent cognitive and movement tasks are included during later sessions. The program was developed in accordance with well-established principles of motor learning, such as individualisation, specificity, overload, adaptation-progression and variability. Specific goals are to reduce the frequency of multiple-step responses, reduce the frequency of collisions between the stepping foot and stance leg, and increase the speed of grasping reactions. A randomised control trial will be performed to evaluate the efficacy of the training program. A total of 30 community-dwelling older adults (age 64–80) with a recent history of instability or falling will be assigned to either the perturbation-based training or a control group (flexibility/relaxation training), using a stratified randomisation that controls for gender, age and baseline stepping/grasping performance. CIS reactions will be tested immediately before and after the six weeks of training, using platform perturbations as well as a distinctly different method of perturbation (waist pulls) in order to evaluate the generalisability of the training effects. Discussion This study will determine whether perturbation-based balance training can help to reverse specific age-related impairments in balance-recovery reactions. These results will help to guide the development of more effective falls prevention programs, which may ultimately lead to reduced health-care costs and enhanced mobility, independence and quality of life. PMID:17540020

A perturbation-based balance training program for older adults: study protocol for a randomised controlled trial.

PubMed

Mansfield, Avril; Peters, Amy L; Liu, Barbara A; Maki, Brian E

2007-05-31

Previous research investigating exercise as a means of falls prevention in older adults has shown mixed results. Lack of specificity of the intervention may be an important factor contributing to negative results. Change-in-support (CIS) balance reactions, which involve very rapid stepping or grasping movements of the limbs, play a critical role in preventing falls; hence, a training program that improves ability to execute effective CIS reactions could potentially have a profound effect in reducing risk of falling. This paper describes: 1) the development of a perturbation-based balance training program that targets specific previously-reported age-related impairments in CIS reactions, and 2) a study protocol to evaluate the efficacy of this new training program. The training program involves use of unpredictable, multi-directional moving-platform perturbations to evoke stepping and grasping reactions. Perturbation magnitude is gradually increased over the course of the 6-week program, and concurrent cognitive and movement tasks are included during later sessions. The program was developed in accordance with well-established principles of motor learning, such as individualisation, specificity, overload, adaptation-progression and variability. Specific goals are to reduce the frequency of multiple-step responses, reduce the frequency of collisions between the stepping foot and stance leg, and increase the speed of grasping reactions. A randomised control trial will be performed to evaluate the efficacy of the training program. A total of 30 community-dwelling older adults (age 64-80) with a recent history of instability or falling will be assigned to either the perturbation-based training or a control group (flexibility/relaxation training), using a stratified randomisation that controls for gender, age and baseline stepping/grasping performance. CIS reactions will be tested immediately before and after the six weeks of training, using platform perturbations as well as a distinctly different method of perturbation (waist pulls) in order to evaluate the generalisability of the training effects. This study will determine whether perturbation-based balance training can help to reverse specific age-related impairments in balance-recovery reactions. These results will help to guide the development of more effective falls prevention programs, which may ultimately lead to reduced health-care costs and enhanced mobility, independence and quality of life.

Hiking with DiabetesRisks and Benefits.

PubMed

Jenkins, David W; Jenks, Alexander

2017-09-01

Exercise is highly beneficial for persons with diabetes. Similar to many other patients, those with diabetes may be reluctant to exercise given a lack of motivation and proper instruction regarding an exercise prescription. In general, medical providers are poorly equipped to develop an exercise prescription and furnish motivation. Attempts to find activities that not only provide effective aerobic challenges but also are enjoyable to participate in are fraught with difficulty. Hiking as a potential option for a safe and enjoyable activity is discussed, including the possible downsides. Multiple publications were reviewed using key words. A review of the literature uncovered limited publications or controlled trials that discussed the use of hiking per se as an activity for the management of diabetes. Newer studies reviewing weightbearing exercise and diabetic polyneuropathy and those discussing the advantages of trekking poles for balance and proprioception are cited in support of the recommendation for hiking as an activity for those with diabetes. Exercise has been shown to substantially benefit individuals with diabetes, but convincing patients with diabetes to exercise is daunting. Hiking, unlike other, more tedious exercise programs, may be an exercise option that persons with diabetes might find enjoyable. Hiking may encourage balance training and reduced ground reaction forces. These benefits may be augmented by trekking poles, which may likewise counter the concerns of the uneven surfaces that present challenges to the hiker with diabetes.

Rifampin phosphotransferase is an unusual antibiotic resistance kinase

PubMed Central

Stogios, Peter J.; Cox, Georgina; Spanogiannopoulos, Peter; Pillon, Monica C.; Waglechner, Nicholas; Skarina, Tatiana; Koteva, Kalinka; Guarné, Alba; Savchenko, Alexei; Wright, Gerard D.

2016-01-01

Rifampin (RIF) phosphotransferase (RPH) confers antibiotic resistance by conversion of RIF and ATP, to inactive phospho-RIF, AMP and Pi. Here we present the crystal structure of RPH from Listeria monocytogenes (RPH-Lm), which reveals that the enzyme is comprised of three domains: two substrate-binding domains (ATP-grasp and RIF-binding domains); and a smaller phosphate-carrying His swivel domain. Using solution small-angle X-ray scattering and mutagenesis, we reveal a mechanism where the swivel domain transits between the spatially distinct substrate-binding sites during catalysis. RPHs are previously uncharacterized dikinases that are widespread in environmental and pathogenic bacteria. These enzymes are members of a large unexplored group of bacterial enzymes with substrate affinities that have yet to be fully explored. Such an enzymatically complex mechanism of antibiotic resistance augments the spectrum of strategies used by bacteria to evade antimicrobial compounds. PMID:27103605

Exercise training reduces peripheral arterial stiffness and myocardial oxygen demand in young prehypertensive subjects.

PubMed

Beck, Darren T; Martin, Jeffrey S; Casey, Darren P; Braith, Randy W

2013-09-01

Large artery stiffness is a major risk factor for the development of hypertension and cardiovascular disease. Persistent prehypertension accelerates the progression of arterial stiffness. Forty-three unmedicated prehypertensive (systolic blood pressure (SBP) = 120-139 mm Hg or diastolic blood pressure (DBP) = 80-89 mm Hg) men and women and 15 normotensive time-matched control subjects (NMTCs; n = 15) aged 18-35 years of age met screening requirements and participated in the study. Prehypertensive subjects were randomly assigned to a resistance exercise training (PHRT; n = 15), endurance exercise training (PHET; n = 13) or time-control group (PHTC; n = 15). Treatment groups performed exercise training 3 days per week for 8 weeks. Pulse wave analysis, pulse wave velocity (PWV), and central and peripheral blood pressures were evaluated before and after exercise intervention or time-matched control. PHRT and PHET reduced resting SBP by 9.6±3.6mm Hg and 11.9±3.4mm Hg, respectively, and DBP by 8.0±5.1mm Hg and 7.2±3.4mm Hg, respectively (P < 0.05). PHRT and PHET decreased augmentation index (AIx) by 7.5% ± 2.8% and 8.1% ± 3.2% (P < 0.05), AIx@75 by 8.0% ± 3.2% and 9.2% ± 3.8% (P < 0.05), and left ventricular wasted pressure energy, an index of extra left ventricular myocardial oxygen requirement due to early systolic wave reflection, by 573±161 dynes s/cm(2) and 612±167 dynes s/cm(2) (P < 0.05), respectively. PHRT and PHET reduced carotid-radial PWV by 1.02±0.32 m/sec and 0.92±0.36 m/sec (P < 0.05) and femoral-distal PWV by 1.04±0.31 m/sec and 1.34±0.33 m/sec (P < 0.05), respectively. No significant changes were observed in the time-control groups. This study suggests that both resistance and endurance exercise alone effectively reduce peripheral arterial stiffness, central blood pressures, augmentation index, and myocardial oxygen demand in young prehypertensive subjects.

Exercise Training Reduces Peripheral Arterial Stiffness and Myocardial Oxygen Demand in Young Prehypertensive Subjects

PubMed Central

2013-01-01

BACKGROUND Large artery stiffness is a major risk factor for the development of hypertension and cardiovascular disease. Persistent prehypertension accelerates the progression of arterial stiffness. METHODS Forty-three unmedicated prehypertensive (systolic blood pressure (SBP) = 120–139mm Hg or diastolic blood pressure (DBP) = 80–89mm Hg) men and women and 15 normotensive time-matched control subjects (NMTCs; n = 15) aged 18–35 years of age met screening requirements and participated in the study. Prehypertensive subjects were randomly assigned to a resistance exercise training (PHRT; n = 15), endurance exercise training (PHET; n = 13) or time-control group (PHTC; n = 15). Treatment groups performed exercise training 3 days per week for 8 weeks. Pulse wave analysis, pulse wave velocity (PWV), and central and peripheral blood pressures were evaluated before and after exercise intervention or time-matched control. RESULTS PHRT and PHET reduced resting SBP by 9.6±3.6mm Hg and 11.9±3.4mm Hg, respectively, and DBP by 8.0±5.1mm Hg and 7.2±3.4mm Hg, respectively (P < 0.05). PHRT and PHET decreased augmentation index (AIx) by 7.5% ± 2.8% and 8.1% ± 3.2% (P < 0.05), AIx@75 by 8.0% ± 3.2% and 9.2% ± 3.8% (P < 0.05), and left ventricular wasted pressure energy, an index of extra left ventricular myocardial oxygen requirement due to early systolic wave reflection, by 573±161 dynes s/cm2 and 612±167 dynes s/cm2 (P < 0.05), respectively. PHRT and PHET reduced carotid–radial PWV by 1.02±0.32 m/sec and 0.92±0.36 m/sec (P < 0.05) and femoral–distal PWV by 1.04±0.31 m/sec and 1.34±0.33 m/sec (P < 0.05), respectively. No significant changes were observed in the time-control groups. CONCLUSIONS This study suggests that both resistance and endurance exercise alone effectively reduce peripheral arterial stiffness, central blood pressures, augmentation index, and myocardial oxygen demand in young prehypertensive subjects. PMID:23736111

Increased respiratory neural drive and work of breathing in exercise-induced laryngeal obstruction.

PubMed

Walsted, Emil S; Faisal, Azmy; Jolley, Caroline J; Swanton, Laura L; Pavitt, Matthew J; Luo, Yuan-Ming; Backer, Vibeke; Polkey, Michael I; Hull, James H

2018-02-01

Exercise-induced laryngeal obstruction (EILO), a phenomenon in which the larynx closes inappropriately during physical activity, is a prevalent cause of exertional dyspnea in young individuals. The physiological ventilatory impact of EILO and its relationship to dyspnea are poorly understood. The objective of this study was to evaluate exercise-related changes in laryngeal aperture on ventilation, pulmonary mechanics, and respiratory neural drive. We prospectively evaluated 12 subjects (6 with EILO and 6 healthy age- and gender-matched controls). Subjects underwent baseline spirometry and a symptom-limited incremental exercise test with simultaneous and synchronized recording of endoscopic video and gastric, esophageal, and transdiaphragmatic pressures, diaphragm electromyography, and respiratory airflow. The EILO and control groups had similar peak work rates and minute ventilation (V̇e) (work rate: 227 ± 35 vs. 237 ± 35 W; V̇e: 103 ± 20 vs. 98 ± 23 l/min; P > 0.05). At submaximal work rates (140-240 W), subjects with EILO demonstrated increased work of breathing ( P < 0.05) and respiratory neural drive ( P < 0.05), developing in close temporal association with onset of endoscopic evidence of laryngeal closure ( P < 0.05). Unexpectedly, a ventilatory increase ( P < 0.05), driven by augmented tidal volume ( P < 0.05), was seen in subjects with EILO before the onset of laryngeal closure; there were however no differences in dyspnea intensity between groups. Using simultaneous measurements of respiratory mechanics and diaphragm electromyography with endoscopic video, we demonstrate, for the first time, increased work of breathing and respiratory neural drive in association with the development of EILO. Future detailed investigations are now needed to understand the role of upper airway closure in causing exertional dyspnea and exercise limitation. NEW & NOTEWORTHY Exercise-induced laryngeal obstruction is a prevalent cause of exertional dyspnea in young individuals; yet, how laryngeal closure affects breathing is unknown. In this study we synchronized endoscopic video with respiratory physiological measurements, thus providing the first detailed commensurate assessment of respiratory mechanics and neural drive in relation to laryngeal closure. Laryngeal closure was associated with increased work of breathing and respiratory neural drive preceded by an augmented tidal volume and a rise in minute ventilation.

Blood pressure regulation X: what happens when the muscle pump is lost? Post-exercise hypotension and syncope.

PubMed

Halliwill, John R; Sieck, Dylan C; Romero, Steven A; Buck, Tahisha M; Ely, Matthew R

2014-03-01

Syncope which occurs suddenly in the setting of recovery from exercise, known as post-exercise syncope, represents a failure of integrative physiology during recovery from exercise. We estimate that between 50 and 80% of healthy individuals will develop pre-syncopal signs and symptoms if subjected to a 15-min head-up tilt following exercise. Post-exercise syncope is most often neurally mediated syncope during recovery from exercise, with a combination of factors associated with post-exercise hypotension and loss of the muscle pump contributing to the onset of the event. One can consider the initiating reduction in blood pressure as the tip of the proverbial iceberg. What is needed is a clear model of what lies under the surface; a model that puts the observational variations in context and provides a rational framework for developing strategic physical or pharmacological countermeasures to ultimately protect cerebral perfusion and avert loss of consciousness. This review summarizes the current mechanistic understanding of post-exercise syncope and attempts to categorize the variation of the physiological processes that arise in multiple exercise settings. Newer investigations into the basic integrative physiology of recovery from exercise provide insight into the mechanisms and potential interventions that could be developed as countermeasures against post-exercise syncope. While physical counter maneuvers designed to engage the muscle pump and augment venous return are often found to be beneficial in preventing a significant drop in blood pressure after exercise, countermeasures that target the respiratory pump and pharmacological countermeasures based on the involvement of histamine receptors show promise.

Blood pressure regulation X: What happens when the muscle pump is lost? Post-exercise hypotension and syncope

PubMed Central

Halliwill, John R.; Sieck, Dylan C.; Romero, Steven A.; Buck, Tahisha M.; Ely, Matthew R.

2013-01-01

Syncope which occurs suddenly in the setting of recovery from exercise, known as post-exercise syncope, represents a failure of integrative physiology during recovery from exercise. We estimate that between 50 and 80% of healthy individuals will develop pre-syncopal signs and symptoms if subjected to a 15-min head-up tilt following exercise. Post-exercise syncope is most often neurally mediated syncope during recovery from exercise, with a combination of factors associated with post-exercise hypotension and loss of the muscle pump contributing to the onset of the event. One can consider the initiating reduction in blood pressure as the tip of the proverbial iceberg. What is needed is a clear model of what lies under the surface; a model that puts the observational variations in context and provides a rational framework for developing strategic physical or pharmacological countermeasures to ultimately protect cerebral perfusion and avert loss of consciousness. This review summarizes the current mechanistic understanding of post-exercise syncope and attempts to categorize the variation of the physiological processes that arise in multiple exercise settings. Newer investigations into the basic integrative physiology of recovery from exercise provide insight into the mechanisms and potential interventions that could be developed as countermeasures against post-exercise syncope. While physical counter maneuvers designed to engage the muscle pump and augment venous return are often found to be beneficial in preventing a significant drop in blood pressure after exercise, countermeasures that target the respiratory pump and pharmacological countermeasures based on the involvement of histamine receptors show promise. PMID:24197081

A soft-contact model for computing safety margins in human prehension.

PubMed

Singh, Tarkeshwar; Ambike, Satyajit

2017-10-01

The soft human digit tip forms contact with grasped objects over a finite area and applies a moment about an axis normal to the area. These moments are important for ensuring stability during precision grasping. However, the contribution of these moments to grasp stability is rarely investigated in prehension studies. The more popular hard-contact model assumes that the digits exert a force vector but no free moment on the grasped object. Many sensorimotor studies use this model and show that humans estimate friction coefficients to scale the normal force to grasp objects stably, i.e. the smoother the surface, the tighter the grasp. The difference between the applied normal force and the minimal normal force needed to prevent slipping is called safety margin and this index is widely used as a measure of grasp planning. Here, we define and quantify safety margin using a more realistic contact model that allows digits to apply both forces and moments. Specifically, we adapt a soft-contact model from robotics and demonstrate that the safety margin thus computed is a more accurate and robust index of grasp planning than its hard-contact variant. Previously, we have used the soft-contact model to propose two indices of grasp planning that show how humans account for the shape and inertial properties of an object. A soft-contact based safety margin offers complementary insights by quantifying how humans may account for surface properties of the object and skin tissue during grasp planning and execution. Copyright © 2017 Elsevier B.V. All rights reserved.

Unusual hand postures but not familiar tools show motor equivalence with precision grasping.

PubMed

Tang, Rixin; Whitwell, Robert L; Goodale, Melvyn A

2016-06-01

A central question in sensorimotor control is whether or not actions performed with the hands and corresponding actions performed with tools share a common underlying motor plan, even though different muscles and effectors are engaged. There is certainly evidence that tools used to extend the reach of the limb can be incorporated into the body schema after training. But even so, it is not clear whether or not actions such as grasping with tools and grasping with the fingers share the same programming network, i.e. show 'motor equivalence'. Here we first show that feedback-appropriate motor programming for grasps with atypical hand postures readily transfers to stereotypical precision grasps. In stark contrast, however, we find no evidence for an analogous transfer of the programming for grasps using tools to the same stereotypical precision grasps. These findings have important implications for our understanding of body schema. Although the extension of the limb that is afforded by tool use may be incorporated into the body schema, the programming of a grasping movement made with tools appears to resist such incorporation. It could be the case that the proprioceptive signals from the limb can be easily updated to reflect the end of a tool held in the hand, but the motor programs and sensory signals associated with grasping with the thumb and finger cannot be easily adapted to control the opening and closing of a tool. Instead, new but well-practiced motor programs are put in place for tool use that do not exhibit motor equivalence with manual grasping. Copyright © 2016 Elsevier B.V. All rights reserved.

A force vector and surface orientation sensor for intelligent grasping

NASA Technical Reports Server (NTRS)

Mcglasson, W. D.; Lorenz, R. D.; Duffie, N. A.; Gale, K. L.

1991-01-01

The paper discusses a force vector and surface orientation sensor suitable for intelligent grasping. The use of a novel four degree-of-freedom force vector robotic fingertip sensor allows efficient, real time intelligent grasping operations. The basis of sensing for intelligent grasping operations is presented and experimental results demonstrate the accuracy and ease of implementation of this approach.

Grasps Recognition and Evaluation of Stroke Patients for Supporting Rehabilitation Therapy

PubMed Central

Sale, Patrizio; Nijenhuis, Sharon; Prange, Gerdienke; Amirabdollahian, Farshid

2014-01-01

Stroke survivors often suffer impairments on their wrist and hand. Robot-mediated rehabilitation techniques have been proposed as a way to enhance conventional therapy, based on intensive repeated movements. Amongst the set of activities of daily living, grasping is one of the most recurrent. Our aim is to incorporate the detection of grasps in the machine-mediated rehabilitation framework so that they can be incorporated into interactive therapeutic games. In this study, we developed and tested a method based on support vector machines for recognizing various grasp postures wearing a passive exoskeleton for hand and wrist rehabilitation after stroke. The experiment was conducted with ten healthy subjects and eight stroke patients performing the grasping gestures. The method was tested in terms of accuracy and robustness with respect to intersubjects' variability and differences between different grasps. Our results show reliable recognition while also indicating that the recognition accuracy can be used to assess the patients' ability to consistently repeat the gestures. Additionally, a grasp quality measure was proposed to measure the capabilities of the stroke patients to perform grasp postures in a similar way than healthy people. These two measures can be potentially used as complementary measures to other upper limb motion tests. PMID:25258709

Action Categorization in Rhesus Monkeys: discrimination of grasping from non-grasping manual motor acts.

PubMed

Nelissen, Koen; Vanduffel, Wim

2017-11-08

The ability to recognize others' actions is an important aspect of social behavior. While neurophysiological and behavioral research in monkeys has offered a better understanding of how the primate brain processes this type of information, further insight with respect to the neural correlates of action recognition requires tasks that allow recording of brain activity or perturbing brain regions while monkeys simultaneously make behavioral judgements about certain aspects of observed actions. Here we investigated whether rhesus monkeys could actively discriminate videos showing grasping or non-grasping manual motor acts in a two-alternative categorization task. After monkeys became proficient in this task, we tested their ability to generalize to a number of untrained, novel videos depicting grasps or other manual motor acts. Monkeys generalized to a wide range of novel human or conspecific grasping and non-grasping motor acts. They failed, however, for videos showing unfamiliar actions such as a non-biological effector performing a grasp, or a human hand touching an object with the back of the hand. This study shows the feasibility of training monkeys to perform active judgements about certain aspects of observed actions, instrumental for causal investigations into the neural correlates of action recognition.

Nutritional status, functional capacity and exercise rehabilitation in end-stage renal disease.

PubMed

Mercer, T H; Koufaki, P; Naish, P F

2004-05-01

A significant percentage of patients with end-stage renal disease are malnourished and/or muscle wasted. Uremia is associated with decreased protein synthesis and increased protein degradation. Fortunately, nutritional status has been shown to be a modifiable risk factor in the dialysis population. It has long been proposed that exercise could positively alter the protein synthesis-degradation balance. Resistance training had been considered as the only form of exercise likely to induce anabolism in renal failure patients. However, a small, but growing, body of evidence indicates that for some dialysis patients, favourable improvements in muscle atrophy and fibre hypertrophy can be achieved via predominantly aerobic exercise training. Moreover, some studies tentatively suggest that nutritional status, as measured by SGA, can also be modestly improved by modes and patterns of exercise training that have been shown to also increase muscle fibre cross-sectional area and improve functional capacity. Functional capacity tests can augment the information content of basic nutritional status assessments of dialysis patients and as such are recommended for routine inclusion as a feature of all nutritional status assessments.

A novel cluster-tube self-adaptive robot hand.

PubMed

Fu, Hong; Yang, Haokun; Song, Weishu; Zhang, Wenzeng

2017-01-01

This paper proposes a novel cluster-tube self-adaptive robot hand (CTSA Hand). The CTSA Hand consists of a base, a motor, a transmission mechanism, multiple elastic tendons, and a group of sliding-tube assemblies. Each sliding-tube assembly is composed of a sliding tube, a guide rod, two springs and a hinge. When the hand grasping an object, the object pushes some sliding tubes to different positions according to the surface shape of the object, the motor pulls the tendons tight to cluster tubes. The CTSA Hand can realize self-adaptive grasping of objects of different sizes and shapes. The CTSA Hand can grasp multiple objects simultaneously because the grasping of the hand acts as many grippers in different directions and heights. The grasping forces of the hand are adjusted by a closed-loop control system with potentiometer. Experimental results show that the CTSA Hand has the features of highly self-adaption and large grasping forces when grasping various objects.

Comparisons among tools, surface orientation, and pencil grasp for children 23 months of age.

PubMed

Yakimishyn, Janet E; Magill-Evans, Joyce

2002-01-01

The purpose of this study was to determine whether writing tool type and angle of writing surface affect grasp. Fifty-one children 23 to 24 months of age who were typically developing drew with a primary marker, colored pencil, and small piece of crayon on a table and an easel. The marker and pencil were presented pointing left, right, and toward the child. The order of writing tool presentation was counterbalanced. Grasps were scored with a 5-point rating system and analyzed with dependent t tests. Children used a more mature grasp when drawing with a piece of crayon than with a pencil. No difference in grasp maturity was found when using a pencil compared with a marker. A more mature grasp when drawing on the easel compared with the table was used with the crayon but not with the marker or pencil. Results imply that a short writing tool combined with a vertical surface can influence the grasp of young children.

Representation of grasp postures and anticipatory motor planning in children.

PubMed

Stöckel, Tino; Hughes, Charmayne M L; Schack, Thomas

2012-11-01

In this study, we investigated anticipatory motor planning and the development of cognitive representation of grasp postures in children aged 7, 8, and 9 years. Overall, 9-year-old children were more likely to plan their movements to end in comfortable postures, and have distinct representational structures of certain grasp postures, compared to the 7- and 8-year old children. Additionally, the sensitivity toward comfortable end-states (end-state comfort) was related to the mental representation of certain grasp postures. Children with grasp comfort related and functionally well-structured representations were more likely to have satisfied end-state comfort in both the simple and the advanced planning condition. In contrast, end-state comfort satisfaction for the advanced planning condition was much lower for children whose cognitive representations were not structured by grasp comfort. The results of the present study support the notion that cognitive action representation plays an important role in the planning and control of grasp postures.

Human grasping database for activities of daily living with depth, color and kinematic data streams.

PubMed

Saudabayev, Artur; Rysbek, Zhanibek; Khassenova, Raykhan; Varol, Huseyin Atakan

2018-05-29

This paper presents a grasping database collected from multiple human subjects for activities of daily living in unstructured environments. The main strength of this database is the use of three different sensing modalities: color images from a head-mounted action camera, distance data from a depth sensor on the dominant arm and upper body kinematic data acquired from an inertial motion capture suit. 3826 grasps were identified in the data collected during 9-hours of experiments. The grasps were grouped according to a hierarchical taxonomy into 35 different grasp types. The database contains information related to each grasp and associated sensor data acquired from the three sensor modalities. We also provide our data annotation software written in Matlab as an open-source tool. The size of the database is 172 GB. We believe this database can be used as a stepping stone to develop big data and machine learning techniques for grasping and manipulation with potential applications in rehabilitation robotics and intelligent automation.

Effect of exercise augmentation of cognitive behavioural therapy for the treatment of suicidal ideation and depression.

PubMed

Abdollahi, Abbas; LeBouthillier, Daniel M; Najafi, Mahmoud; Asmundson, Gordon J G; Hosseinian, Simin; Shahidi, Shahriar; Carlbring, Per; Kalhori, Atefeh; Sadeghi, Hassan; Jalili, Marzieh

2017-09-01

Suicidal ideation and depression are prevalent and costly conditions that reduce quality of life. This study was designed to determine the efficacy of exercise as an adjunct to cognitive behavioural therapy (CBT) for suicidal ideation and depression among depressed individuals. In a randomized clinical trial, 54 mildly to moderately depressed patients (54% female, mean age=48.25) were assigned to a combined CBT and exercise group or to a CBT only group. Both groups received one weekly session of therapy for 12 weeks, while the combined group also completed exercise three times weekly over the same period. Self-reported suicidal ideation, depression, and activities of daily living were measured at the beginning and the end of treatment. Multilevel modelling revealed greater improvements in suicidal ideation, depression, and activities of daily living in the combined CBT and exercise group, compared to the CBT only group. No follow-up data were collected, so the long-term effects (i.e., maintenance of gains) is unclear. The findings revealed that exercise adjunct to CBT effectively decreases both depressive symptoms and suicidal ideation in mildly to moderately depressed individuals. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of simulated microgravity on the sympathetic response to exercise

NASA Technical Reports Server (NTRS)

Woodman, C. R.; Kregel, K. C.; Tipton, C. M.

1997-01-01

Rats exposed to simulated conditions of microgravity exhibit reductions in aerobic exercise capacity that may be due to an impaired ability of the sympathetic nervous system (SNS) to mediate an increase in cardiac output and to redistribute blood flow. The purpose of this study was to quantify the sympathetic response to exercise in rats after exposure to 14 days of simulated microgravity or control conditions. To achieve this aim, rats were exposed to 14 days of head-down suspension (HDS) or cage control (CC) conditions. On day 14, norepinephrine (NE) synthesis was blocked with alpha-methyl-p-tyrosine, and the rate of NE depletion after synthesis blockade was used to estimate SNS activity in the left ventricle, spleen, and soleus muscle during treadmill exercise at 75% of maximal oxygen uptake. When compared with CC rats, the sympathetic response to exercise in HDS rats was characterized by a lower rate of NE depletion in the left ventricle (-82%) and spleen (-42%). The rate of NE depletion in the soleus muscle was 47% higher. These differences could contribute to the decrement in aerobic capacity of HDS rats by impairing their ability to augment cardiac output and to redirect blood flow to actively contracting skeletal muscle during exercise.

Audio-Visual Stimulation in Conjunction with Functional Electrical Stimulation to Address Upper Limb and Lower Limb Movement Disorder.

PubMed

Kumar, Deepesh; Verma, Sunny; Bhattacharya, Sutapa; Lahiri, Uttama

2016-06-13

Neurological disorders often manifest themselves in the form of movement deficit on the part of the patient. Conventional rehabilitation often used to address these deficits, though powerful are often monotonous in nature. Adequate audio-visual stimulation can prove to be motivational. In the research presented here we indicate the applicability of audio-visual stimulation to rehabilitation exercises to address at least some of the movement deficits for upper and lower limbs. Added to the audio-visual stimulation, we also use Functional Electrical Stimulation (FES). In our presented research we also show the applicability of FES in conjunction with audio-visual stimulation delivered through VR-based platform for grasping skills of patients with movement disorder.

Technical Rebuilding of Movement Function Using Functional Electrical Stimulation

NASA Astrophysics Data System (ADS)

Gföhler, Margit

To rebuild lost movement functions, neuroprostheses based on functional electrical stimulation (FES) artificially activate skeletal muscles in corresponding sequences, using both residual body functions and artificial signals for control. Besides the functional gain, FES training also brings physiological and psychological benefits for spinal cord-injured subjects. In this chapter, current stimulation technology and the main components of FES-based neuroprostheses including enhanced control systems are presented. Technology and application of FES cycling and rowing, both approaches that enable spinal cord-injured subjects to participate in mainstream activities and improve their health and fitness by exercising like able-bodied subjects, are discussed in detail, and an overview of neuroprostheses that aim at restoring movement functions for daily life as walking or grasping is given.

Combined Interval Training and Post-exercise Nutrition in Type 2 Diabetes: A Randomized Control Trial.

PubMed

Francois, Monique E; Durrer, Cody; Pistawka, Kevin J; Halperin, Frank A; Chang, Courtney; Little, Jonathan P

2017-01-01

Background: High-intensity interval training (HIIT) can improve several aspects of cardiometabolic health. Previous studies have suggested that adaptations to exercise training can be augmented with post-exercise milk or protein consumption, but whether this nutritional strategy can impact the cardiometabolic adaptations to HIIT in type 2 diabetes is unknown. Objective: To determine if the addition of a post-exercise milk or protein beverage to a high-intensity interval training (HIIT) intervention improves cardiometabolic health in individuals with type 2 diabetes. Design: In a proof-of-concept, double-blind clinical trial 53 adults with uncomplicated type 2 diabetes were randomized to one of three nutritional beverages (500 mL skim-milk, macronutrient control, or flavored water placebo) consumed after exercise (3 days/week) during a 12 week low-volume HIIT intervention. HIIT involved 10 X 1-min high-intensity intervals separated by 1-min low-intensity recovery periods. Two sessions per week were cardio-based (at ~90% of heart rate max) and one session involved resistance-based exercises (at RPE of 5-6; CR-10 scale) in the same interval pattern. Continuous glucose monitoring (CGM), glycosylated hemoglobin (HbA 1c ), body composition (dual-energy X-ray absorptiometry), cardiorespiratory fitness ([Formula: see text]), blood pressure, and endothelial function (%FMD) were measured before and after the intervention. Results: There were significant main effects of time (all p < 0.05) but no difference between groups (Interaction: all p > 0.71) for CGM 24-h mean glucose (-0.5 ± 1.1 mmol/L), HbA 1c (-0.2 ± 0.4%), percent body fat (-0.8 ± 1.6%), and lean mass (+1.1 ± 2.8 kg). Similarly, [Formula: see text] (+2.5 ± 1.6 mL/kg/min) and %FMD (+1.4 ± 1.9%) were increased, and mean arterial blood pressure reduced (-6 ± 7 mmHg), after 12 weeks of HIIT (all p < 0.01) with no difference between beverage groups (Interaction: all p > 0.11). Conclusion: High-intensity interval training is a potent stimulus for improving several important metabolic and cardiovascular risk factors in type 2 diabetes. The benefits of HIIT are not augmented by the addition of post-exercise protein.

Combined Interval Training and Post-exercise Nutrition in Type 2 Diabetes: A Randomized Control Trial

PubMed Central

Francois, Monique E.; Durrer, Cody; Pistawka, Kevin J.; Halperin, Frank A.; Chang, Courtney; Little, Jonathan P.

2017-01-01

Background: High-intensity interval training (HIIT) can improve several aspects of cardiometabolic health. Previous studies have suggested that adaptations to exercise training can be augmented with post-exercise milk or protein consumption, but whether this nutritional strategy can impact the cardiometabolic adaptations to HIIT in type 2 diabetes is unknown. Objective: To determine if the addition of a post-exercise milk or protein beverage to a high-intensity interval training (HIIT) intervention improves cardiometabolic health in individuals with type 2 diabetes. Design: In a proof-of-concept, double-blind clinical trial 53 adults with uncomplicated type 2 diabetes were randomized to one of three nutritional beverages (500 mL skim-milk, macronutrient control, or flavored water placebo) consumed after exercise (3 days/week) during a 12 week low-volume HIIT intervention. HIIT involved 10 X 1-min high-intensity intervals separated by 1-min low-intensity recovery periods. Two sessions per week were cardio-based (at ~90% of heart rate max) and one session involved resistance-based exercises (at RPE of 5–6; CR-10 scale) in the same interval pattern. Continuous glucose monitoring (CGM), glycosylated hemoglobin (HbA1c), body composition (dual-energy X-ray absorptiometry), cardiorespiratory fitness (V˙O2peak), blood pressure, and endothelial function (%FMD) were measured before and after the intervention. Results: There were significant main effects of time (all p < 0.05) but no difference between groups (Interaction: all p > 0.71) for CGM 24-h mean glucose (−0.5 ± 1.1 mmol/L), HbA1c (−0.2 ± 0.4%), percent body fat (−0.8 ± 1.6%), and lean mass (+1.1 ± 2.8 kg). Similarly, V˙O2peak (+2.5 ± 1.6 mL/kg/min) and %FMD (+1.4 ± 1.9%) were increased, and mean arterial blood pressure reduced (−6 ± 7 mmHg), after 12 weeks of HIIT (all p < 0.01) with no difference between beverage groups (Interaction: all p > 0.11). Conclusion: High-intensity interval training is a potent stimulus for improving several important metabolic and cardiovascular risk factors in type 2 diabetes. The benefits of HIIT are not augmented by the addition of post-exercise protein. PMID:28790929

Branched-Chain Amino Acid Supplementation in Combination with Voluntary Running Improves Body Composition in Female C57BL/6 Mice.

PubMed

Platt, Kristen M; Charnigo, Richard J; Shertzer, Howard G; Pearson, Kevin J

2016-01-01

Exercise is an inexpensive intervention that may be used to reduce obesity and its consequences. In addition, many individuals who regularly exercise utilize dietary supplements to enhance their exercise routine and to accelerate fat loss or increase lean mass. Branched-chain amino acids (BCAAs) are a popular supplement and have been shown to produce a number of beneficial effects in rodent models and humans. Therefore, we hypothesized that BCAA supplementation would protect against high fat diet (HFD)-induced glucose intolerance and obesity in mice with and without access to exercise. We subjected 80 female C57BL/6 mice to a paradigm of HFD feeding, exercise in the form of voluntary wheel running, and BCAA supplementation in the drinking water for 16 weeks (n = 10 per group). Body weight was monitored weekly, while food and water consumption were recorded twice weekly. During the 5th, 10th, and 15th weeks of treatment, glucose tolerance and body composition were analyzed. Exercise significantly improved glucose tolerance in both control-fed and HFD-fed mice. BCAA supplementation, however, did not significantly alter glucose tolerance in any treatment group. While BCAA supplements did not improve lean to fat mass ratio in sedentary mice, it significantly augmented the effects of exercise on this parameter.

Exercise-induced cardioprotection--biochemical, morphological and functional evidence in whole tissue and isolated mitochondria.

PubMed

Ascensão, António; Ferreira, Rita; Magalhães, José

2007-04-12

Myocardial injury is a major contributor to the morbidity and mortality associated with coronary artery disease. Regular exercise has been confirmed as a pragmatic countermeasure to protect against cardiac injury. Specifically, endurance exercise has been proven to provide cardioprotection against cardiac insults in both young and old animals. Proposed mechanisms to explain the cardioprotective effects of exercise are mediated, at least partially, by redox changes and include the induction of myocardial heat shock proteins, improved cardiac antioxidant capacity, and/or elevation of other cardioprotective molecules. Understanding the molecular basis for exercise-induced cardioprotection is important in developing exercise strategies to protect the heart during and after insults. Data suggest that these positive modulator effects occur at different levels of cellular organization, being mitochondria fundamental organelles that are sensitive to disturbances imposed by exercise on basal homeostasis. At present, which of these protective mechanisms is essential for exercise-induced cardioprotection remains unclear. This review analyzes the biochemical, morphological and functional outcomes of acute and chronic exercise on the overall cardiac muscle tissue and in isolated mitochondria. Some redox-based mechanisms behind the cross-tolerance effects particularly induced by endurance training, against certain stressors responsible for the impairments in cardiac homeostasis caused by aging, diabetes, drug administration or ischemia-reperfusion are also outlined. Further work should be addressed in order to clarify the precise regulatory mechanisms by which physical exercise augments heart tolerance against many cardiotoxic agents.

A Biologically Inspired Learning to Grasp System

DTIC Science & Technology

2001-10-25

possible extensive discussions of data on the premotor cortex and monkey grasping circuit with Giacomo Rizzolatti , Vittorio Gallese, to whom we express...premotor specialisation for the different types of grasps that Rizzolatti group [3] has found be formed at this age yet. Infants will need to...our gratitude. REFERENCES [1] M. Jeannerod, M.A. Arbib, G. Rizzolatti , H. Sakata, “Grasping objects: the cortical mechanisms of visuomotor

Robot Grasps Rotating Object

NASA Technical Reports Server (NTRS)

Wilcox, Brian H.; Tso, Kam S.; Litwin, Todd E.; Hayati, Samad A.; Bon, Bruce B.

1991-01-01

Experimental robotic system semiautomatically grasps rotating object, stops rotation, and pulls object to rest in fixture. Based on combination of advanced techniques for sensing and control, constructed to test concepts for robotic recapture of spinning artificial satellites. Potential terrestrial applications for technology developed with help of system includes tracking and grasping of industrial parts on conveyor belts, tracking of vehicles and animals, and soft grasping of moving objects in general.

Encoding of Both Reaching and Grasping Kinematics in Dorsal and Ventral Premotor Cortices

PubMed Central

Best, Matthew D.

2017-01-01

Classically, it has been hypothesized that reach-to-grasp movements arise from two discrete parietofrontal cortical networks. As part of these networks, the dorsal premotor cortex (PMd) has been implicated in the control of reaching movements of the arm, whereas the ventral premotor cortex (PMv) has been associated with the control of grasping movements of the hand. Recent studies have shown that such a strict delineation of function along anatomical boundaries is unlikely, partly because reaching to different locations can alter distal hand kinematics and grasping different objects can affect kinematics of the proximal arm. Here, we used chronically implanted multielectrode arrays to record unit-spiking activity in both PMd and PMv simultaneously while rhesus macaques engaged in a reach-to-grasp task. Generalized linear models were used to predict the spiking activity of cells in both areas as a function of different kinematic parameters, as well as spike history. To account for the influence of reaching on hand kinematics and vice versa, we applied demixed principal components analysis to define kinematics synergies that maximized variance across either different object locations or grip types. We found that single cells in both PMd and PMv encode the kinematics of both reaching and grasping synergies, suggesting that this classical division of reach and grasp in PMd and PMv, respectively, does not accurately reflect the encoding preferences of cells in those areas. SIGNIFICANCE STATEMENT For reach-to-grasp movements, the dorsal premotor cortex (PMd) has been implicated in the control of reaching movements of the arm, whereas the ventral premotor cortex (PMv) has been associated with the control of grasping movements of the hand. We recorded unit-spiking activity in PMd and PMv simultaneously while macaques performed a reach-to-grasp task. We modeled the spiking activity of neurons as a function of kinematic parameters and spike history. We applied demixed principal components analysis to define kinematics synergies. We found that single units in both PMd and PMv encode the kinematics of both reaching and grasping synergies, suggesting that the division of reach and grasp in PMd and PMv, respectively, cannot be made based on their encoding properties. PMID:28077725

Effect of pelvic floor muscle exercises in the treatment of urinary incontinence during pregnancy and the postpartum period.

PubMed

Dinc, Ayten; Kizilkaya Beji, Nezihe; Yalcin, Onay

2009-10-01

The aim of this study was to determine the effectiveness of pelvic floor muscle exercises on urinary incontinence during pregnancy and the postpartum period. The study was carried out on 80 pregnant women (study group, 40 subjects; control group, 40 subjects).The study group was trained by the researcher on how to do the pelvic floor muscle exercises. Both groups were evaluated for pelvic floor muscle strength and urinary complaints in their 36th to 38th week of pregnancy and postpartum sixth to eighth week. The study group had a significant decrease in urinary incontinence episodes during pregnancy and in the postpartum period, and their pelvic floor muscle strength increased to a larger extent. Control group had an increase in the postpartum muscle strength and decrease in the incontinence episodes in the postpartum period. Pelvic floor muscle exercises are quite effective in the augmentation of the pelvic floor muscle strength and consequently in the treatment of urinary incontinence.

The extended object-grasping network.

PubMed

Gerbella, Marzio; Rozzi, Stefano; Rizzolatti, Giacomo

2017-10-01

Grasping is the most important skilled motor act of primates. It is based on a series of sensorimotor transformations through which the affordances of the objects to be grasped are transformed into appropriate hand movements. It is generally accepted that a circuit formed by inferior parietal areas AIP and PFG and ventral premotor area F5 represents the core circuit for sensorimotor transformations for grasping. However, selection and control of appropriate grip should also depend on higher-order information, such as the meaning of the object to be grasped, and the overarching goal of the action in which grasping is embedded. In this review, we describe recent findings showing that specific sectors of the ventrolateral prefrontal cortex are instrumental in controlling higher-order aspects of grasping. We show that these prefrontal sectors control the premotor cortex through two main gateways: the anterior subdivision of ventral area F5-sub-area F5a-, and the pre-supplementary area (area F6). We then review functional studies showing that both F5a and F6, besides being relay stations of prefrontal information, also play specific roles in grasping. Namely, sub-area F5a is involved in stereoscopic analysis of 3D objects, and in planning cue-dependent grasping activity. As for area F6, this area appears to play a crucial role in determining when to execute the motor program encoded in the parieto-premotor circuit. The recent discovery that area F6 contains a set of neurons encoding specific grip types suggests that this area, besides controlling "when to go", also may control the grip type, i.e., "how to go". We conclude by discussing clinical syndromes affecting grasping actions and their possible mechanisms.

A Novel Device for Grasping Assessment during Functional Tasks: Preliminary Results

PubMed Central

Rocha, Ana Carolinne Portela; Tudella, Eloisa; Pedro, Leonardo M.; Appel, Viviane Cristina Roma; da Silva, Louise Gracelli Pereira; Caurin, Glauco Augusto de Paula

2016-01-01

This paper presents a methodology and first results obtained in a study with a novel device that allows the analysis of grasping quality. Such a device is able to acquire motion information of upper limbs allowing kinetic of manipulation analysis as well. A pilot experiment was carried out with six groups of typically developing children aged between 5 and 10 years, with seven to eight children in each one. The device, designed to emulate a glass, has an optical system composed by one digital camera and a special convex mirror that together allow image acquisition of grasping hand posture when it is grasped and manipulated. It also carries an Inertial Measurement Unit that captures motion data as acceleration, orientation, and angular velocities. The novel instrumented object is used in our approach to evaluate functional tasks performance in quantitative terms. During tests, each child was invited to grasp the cylindrical part of the device that was placed on the top of a table, simulating the task of drinking a glass of water. In the sequence, the child was oriented to transport the device back to the starting position and release it. The task was repeated three times for each child. A grasping hand posture evaluation is presented as an example to evaluate grasping quality. Additionally, motion patterns obtained with the trials performed with the different groups are presented and discussed. This device is attractive due to its portable characteristics, the small size, and its ability to evaluate grasping form. The results may be also useful to analyze the evolution of the rehabilitation process through reach-to-grasping movement and the grasping images analysis. PMID:26942178

Pulmonary Artery Wedge Pressure Relative to Exercise Work Rate in Older Men and Women.

PubMed

Esfandiari, Sam; Wright, Stephen P; Goodman, Jack M; Sasson, Zion; Mak, Susanna

2017-07-01

An augmented pulmonary artery wedge pressure (PAWP) response may explain exercise intolerance in some humans. However, routine use of exercise hemodynamic testing is limited by a lack of data from normal older men and women. Our objective was to evaluate the exercise PAWP response and the potential for sexual dimorphism in healthy, nondyspneic older adults. Thirty-six healthy volunteers (18 men [54 ± 7 yr] and 18 women [58 ± 6 yr]) were studied at rest (control) and during two stages of semi-upright cycle ergometry, at heart rates of 100 bpm (light exercise) and 120 bpm (moderate exercise). Right heart catheterization was performed to measure pulmonary pressures. The PAWP response to exercise was assessed in context of exercise work rate and body size. At control, PAWP was similar between men and women. Work rates were significantly smaller in women at comparable HR (P < 0.001). PAWP increased similarly at light exercise, with no further increase at moderate exercise. When indexed to work rate alone or work rate adjusted to body weight and height, the PAWP response at light and moderate exercise was significantly elevated in women compared with men (P < 0.05 condition-sex interaction). The change in PAWP relative to the increase in cardiac output did not exceed 2 mm Hg·L·min in any volunteer at moderate exercise. The similar rise in the PAWP response to submaximal exercise occurs despite lower work rate in healthy older women compared with men, even when adjusted for smaller body size. It is important to consider sex in the development of normal reference ranges for exercise hemodynamic testing.

Responses of mirror neurons in area F5 to hand and tool grasping observation

PubMed Central

Rochat, Magali J.; Caruana, Fausto; Jezzini, Ahmad; Escola, Ludovic; Intskirveli, Irakli; Grammont, Franck; Gallese, Vittorio; Rizzolatti, Giacomo

2010-01-01

Mirror neurons are a distinct class of neurons that discharge both during the execution of a motor act and during observation of the same or similar motor act performed by another individual. However, the extent to which mirror neurons coding a motor act with a specific goal (e.g., grasping) might also respond to the observation of a motor act having the same goal, but achieved with artificial effectors, is not yet established. In the present study, we addressed this issue by recording mirror neurons from the ventral premotor cortex (area F5) of two monkeys trained to grasp objects with pliers. Neuron activity was recorded during the observation and execution of grasping performed with the hand, with pliers and during observation of an experimenter spearing food with a stick. The results showed that virtually all neurons responding to the observation of hand grasping also responded to the observation of grasping with pliers and, many of them to the observation of spearing with a stick. However, the intensity and pattern of the response differed among conditions. Hand grasping observation determined the earliest and the strongest discharge, while pliers grasping and spearing observation triggered weaker responses at longer latencies. We conclude that F5 grasping mirror neurons respond to the observation of a family of stimuli leading to the same goal. However, the response pattern depends upon the similarity between the observed motor act and the one executed by the hand, the natural motor template. PMID:20577726

The Influence of Robotic Assistance on Reducing Neuromuscular Effort and Fatigue during Extravehicular Activity Glove Use

NASA Technical Reports Server (NTRS)

Madden, Kaci E.; Deshpande, Ashish D.; Peters, Benjamin J.; Rogers, Jonathan M.; Laske, Evan A.; McBryan, Emily R.

2017-01-01

The three-layered, pressurized space suit glove worn by Extravehicular Activity (EVA) crew members during missions commonly causes hand and forearm fatigue. The Spacesuit RoboGlove (SSRG), a Phase VI EVA space suit glove modified with robotic grasp-assist capabilities, has been developed to augment grip strength in order to improve endurance and reduce the risk of injury in astronauts. The overall goals of this study were to i) quantify the neuromuscular modulations that occur in response to wearing a conventional Phase VI space suit glove (SSG) during a fatiguing task, and ii) determine the efficacy of Spacesuit RoboGlove (SSRG) in reversing the adverse neuromuscular modulations and restoring altered muscular activity to barehanded levels. Six subjects performed a fatigue sequence consisting of repetitive dynamic-gripping interspersed with isometric grip-holds under three conditions: barehanded, wearing pressurized SSG, and wearing pressurized SSRG. Surface electromyography (sEMG) from six forearm muscles (flexor digitorum superficialis (FDS), flexor carpi radialis (FCR), flexor carpi ulnaris (FCU), extensor digitorum (ED), extensor carpi radialis longus (ECRL), and extensor carpi ulnaris (ECU)) and subjective fatigue ratings were collected during each condition. Trends in amplitude and spectral distributions of the sEMG signals were used to derive metrics quantifying neuromuscular effort and fatigue that were compared across the glove conditions. Results showed that by augmenting finger flexion, the SSRG successfully reduced the neuromuscular effort needed to close the fingers of the space suit glove in more than half of subjects during two types of tasks. However, the SSRG required more neuromuscular effort to extend the fingers compared to a conventional SSG in many subjects. Psychologically, the SSRG aided subjects in feeling less fatigued during short periods of intense work compared to the SSG. The results of this study reveal the promise of the SSRG as a grasp-assist device that can improve astronaut performance and reduce the risk of injury by offsetting neuromuscular effort. Modifications to the experimental protocol are needed, however, to improve the outcome of the neuromuscular fatigue metrics and determine the effectiveness of SSRG in increasing astronaut endurance. Nevertheless, these findings will improve the understanding of astronaut-spacesuit interaction and provide direction toward designing improved spacesuit gloves and robotic-assist devices, like the SSRG.

An augmented reality home-training system based on the mirror training and imagery approach.

PubMed

Trojan, Jörg; Diers, Martin; Fuchs, Xaver; Bach, Felix; Bekrater-Bodmann, Robin; Foell, Jens; Kamping, Sandra; Rance, Mariela; Maaß, Heiko; Flor, Herta

2014-09-01

Mirror training and movement imagery have been demonstrated to be effective in treating several clinical conditions, such as phantom limb pain, stroke-induced hemiparesis, and complex regional pain syndrome. This article presents an augmented reality home-training system based on the mirror and imagery treatment approaches for hand training. A head-mounted display equipped with cameras captures one hand held in front of the body, mirrors this hand, and displays it in real time in a set of four different training tasks: (1) flexing fingers in a predefined sequence, (2) moving the hand into a posture fitting into a silhouette template, (3) driving a "Snake" video game with the index finger, and (4) grasping and moving a virtual ball. The system records task performance and transfers these data to a central server via the Internet, allowing monitoring of training progress. We evaluated the system by having 7 healthy participants train with it over the course of ten sessions of 15-min duration. No technical problems emerged during this time. Performance indicators showed that the system achieves a good balance between relatively easy and more challenging tasks and that participants improved significantly over the training sessions. This suggests that the system is well suited to maintain motivation in patients, especially when it is used for a prolonged period of time.

Validation of a mechanism to balance exercise difficulty in robot-assisted upper-extremity rehabilitation after stroke

PubMed Central

2012-01-01

Background The motivation of patients during robot-assisted rehabilitation after neurological disorders that lead to impairments of motor functions is of great importance. Due to the increasing number of patients, increasing medical costs and limited therapeutic resources, clinicians in the future may want patients to practice their movements at home or with reduced supervision during their stay in the clinic. Since people only engage in an activity and are motivated to practice if the outcome matches the effort at which they perform, an augmented feedback application for rehabilitation should take the cognitive and physical deficits of patients into account and incorporate a mechanism that is capable of balancing i.e. adjusting the difficulty of an exercise in an augmented feedback application to the patient's capabilities. Methods We propose a computational mechanism based on Fitts' Law that balances i.e. adjusts the difficulty of an exercise for upper-extremity rehabilitation. The proposed mechanism was implemented into an augmented feedback application consisting of three difficulty conditions (easy, balanced, hard). The task of the exercise was to reach random targets on the screen from a starting point within a specified time window. The available time was decreased with increasing condition difficulty. Ten subacute stroke patients were recruited to validate the mechanism through a study. Cognitive and motor functions of patients were assessed using the upper extremity section of the Fugl-Meyer Assessment, the modified Ashworth scale as well as the Addenbrookes cognitive examination-revised. Handedness of patients was obtained using the Edinburgh handedness inventory. Patients' performance during the execution of the exercises was measured twice, once for the paretic and once for the non-paretic arm. Results were compared using a two-way ANOVA. Post hoc analysis was performed using a Tukey HSD with a significance level of p < 0.05. Results Results show that the mechanism was capable of balancing the difficulty of an exercise to the capabilities of the patients. Medians for both arms show a gradual decrease and significant difference of the number of successful trials with increasing condition difficulty (F2;60 = 44.623; p < 0.01; η2 = 0.623) but no significant difference between paretic and non-paretic arm (F1;60 = 3.768; p = 0.057; η2 = 0.065). Post hoc analysis revealed that, for both arms, the hard condition significantly differed from the easy condition (p < 0.01). In the non-paretic arm there was an additional significant difference between the balanced and the hard condition (p < 0.01). Reducing the time to reach the target, i.e., increasing the difficulty level, additionally revealed significant differences between conditions for movement speeds (F2;59 = 6.013; p < 0.01; η2 = 0.185), without significant differences for hand-closing time (F2;59 = 2.620; p = 0.082; η2 = 0.09), reaction time (F2;59 = 0.978; p = 0.383; η2 = 0.036) and hand-path ratio (F2;59 = 0.054; p = 0.947; η2 = 0.002). The evaluation of a questionnaire further supported the assumption that perceived performance declined with increased effort and increased exercise difficulty leads to frustration. Conclusions Our results support that Fitts' Law indeed constitutes a powerful mechanism for task difficulty adaptation and can be incorporated into exercises for upper-extremity rehabilitation. PMID:22304989

Effects of caffeinated chewing gum on muscle pain during submaximal isometric exercise in individuals with fibromyalgia.

PubMed

Umeda, Masataka; Kempka, Laura; Weatherby, Amy; Greenlee, Brennan; Mansion, Kimberly

2016-04-01

Physical activity is important to manage symptom of fibromyalgia (FM); however, individuals with FM typically experience augmented muscle pain during exercise. This study examined the effects of caffeinated chewing gum on exercise-induced muscle pain in individuals with FM. This study was conducted with a double-blind, placebo-controlled, cross-over design. Twenty-three patients with FM completed a caffeine condition where they consumed a caffeinated chewing gum that contains 100mg of caffeine, and a placebo condition where they consumed a non-caffeinated chewing gum. They completed isometric handgrip exercise at 25% of their maximal strength for 3 min, and muscle pain rating (MPR) was recorded every 30s during exercise. Clinical pain severity was assessed in each condition using a pain questionnaire. The order of the two conditions was randomly determined. MPR increased during exercise, but caffeinated chewing gum did not attenuate the increase in MPR compared to placebo gum. Clinical pain severity was generally associated with the average MPR and the caffeine effects on MPR, calculated as difference in the average MPR between the two conditions. The results suggest that more symptomatic individuals with FM may experience greater exercise-induced muscle pain, but benefit more from caffeinated chewing gum to reduce exercise-induced muscle pain. Copyright © 2016 Elsevier Inc. All rights reserved.

Modeling heat exchange characteristics of long term space operations: Role of skin wettedness and exercise

NASA Technical Reports Server (NTRS)

Gonzalez, Richard R.

1994-01-01

The problems of heat exchange during rest and exercise during long term space operations are covered in this report. Particular attention is given to the modeling and description of the consequences of requirement to exercise in a zero-g atmosphere during Space Shuttle flights, especially long term ones. In space environments, there exists no free convection therefore only forced convection occurring by movement, such as pedalling on a cycle ergometer, augments required heat dissipation necessary to regulate body temperature. The requirement to exercise at discrete periods of the day is good practice in order to resist the deleterious consequences of zero-gravity problems and improve distribution of body fluids. However, during exercise (ca. 180 to 250W), in zero-g environments, the mass of eccrine sweating rests as sheets on the skin surface and the sweat cannot evaporate readily. The use of exercise suits with fabrics that have hydrophobic or outwicking properties somewhat distributes the mass of sweat to a larger surface from which to evaporate. However, with no free convection, increased skin wettedness throughout the body surface induces increasing thermal discomfort, particularly during continuous exercise. This report presents several alternatives to aid in this problem: use of intermittent exercise, methods to quantify local skin wettedness, and introduction of a new effective temperature that integrates thermal stress and heat exchange avenues in a zero-g atmosphere.

Monocular-Based 6-Degree of Freedom Pose Estimation Technology for Robotic Intelligent Grasping Systems

PubMed Central

Liu, Tao; Guo, Yin; Yang, Shourui; Yin, Shibin; Zhu, Jigui

2017-01-01

Industrial robots are expected to undertake ever more advanced tasks in the modern manufacturing industry, such as intelligent grasping, in which robots should be capable of recognizing the position and orientation of a part before grasping it. In this paper, a monocular-based 6-degree of freedom (DOF) pose estimation technology to enable robots to grasp large-size parts at informal poses is proposed. A camera was mounted on the robot end-flange and oriented to measure several featured points on the part before the robot moved to grasp it. In order to estimate the part pose, a nonlinear optimization model based on the camera object space collinearity error in different poses is established, and the initial iteration value is estimated with the differential transformation. Measuring poses of the camera are optimized based on uncertainty analysis. Also, the principle of the robotic intelligent grasping system was developed, with which the robot could adjust its pose to grasp the part. In experimental tests, the part poses estimated with the method described in this paper were compared with those produced by a laser tracker, and results show the RMS angle and position error are about 0.0228° and 0.4603 mm. Robotic intelligent grasping tests were also successfully performed in the experiments. PMID:28216555

Monocular-Based 6-Degree of Freedom Pose Estimation Technology for Robotic Intelligent Grasping Systems.

PubMed

Liu, Tao; Guo, Yin; Yang, Shourui; Yin, Shibin; Zhu, Jigui

2017-02-14

Industrial robots are expected to undertake ever more advanced tasks in the modern manufacturing industry, such as intelligent grasping, in which robots should be capable of recognizing the position and orientation of a part before grasping it. In this paper, a monocular-based 6-degree of freedom (DOF) pose estimation technology to enable robots to grasp large-size parts at informal poses is proposed. A camera was mounted on the robot end-flange and oriented to measure several featured points on the part before the robot moved to grasp it. In order to estimate the part pose, a nonlinear optimization model based on the camera object space collinearity error in different poses is established, and the initial iteration value is estimated with the differential transformation. Measuring poses of the camera are optimized based on uncertainty analysis. Also, the principle of the robotic intelligent grasping system was developed, with which the robot could adjust its pose to grasp the part. In experimental tests, the part poses estimated with the method described in this paper were compared with those produced by a laser tracker, and results show the RMS angle and position error are about 0.0228° and 0.4603 mm. Robotic intelligent grasping tests were also successfully performed in the experiments.

Motivational state, reward value, and Pavlovian cues differentially affect skilled forelimb grasping in rats

PubMed Central

de Clauser, Larissa; Kasper, Hansjörg; Schwab, Martin E.

2016-01-01

Motor skills represent high-precision movements performed at optimal speed and accuracy. Such motor skills are learned with practice over time. Besides practice, effects of motivation have also been shown to influence speed and accuracy of movements, suggesting that fast movements are performed to maximize gained reward over time as noted in previous studies. In rodents, skilled motor performance has been successfully modeled with the skilled grasping task, in which animals use their forepaw to grasp for sugar pellet rewards through a narrow window. Using sugar pellets, the skilled grasping task is inherently tied to motivation processes. In the present study, we performed three experiments modulating animals’ motivation during skilled grasping by changing the motivational state, presenting different reward value ratios, and displaying Pavlovian stimuli. We found in all three studies that motivation affected the speed of skilled grasping movements, with the strongest effects seen due to motivational state and reward value. Furthermore, accuracy of the movement, measured in success rate, showed a strong dependence on motivational state as well. Pavlovian cues had only minor effects on skilled grasping, but results indicate an inverse Pavlovian-instrumental transfer effect on movement speed. These findings have broad implications considering the increasing use of skilled grasping in studies of motor system structure, function, and recovery after injuries. PMID:27194796

The application of a modified neuroprosthetic hand system in a child with a C7 spinal cord injury. Case report.

PubMed

Smith, B T; Mulcahey, M J; Triolo, R J; Betz, R R

1992-08-01

A neuroprosthetic hand system developed at Case Western Reserve University has been modified for use by an 8 year old child with an incomplete C7 spinal cord injury. This system has been adapted to accommodate voluntary thumb and finger extension, and provides stimulated finger flexion and thumb position for lateral and palmar prehension. Three months were required to develop grasp with sufficient strength and coordination for functional use. This period consisted of: implantation and immobilization of percutaneous intramuscular electrodes; stimulated exercise of the muscles of the hand and forearm; programming grasp patterns; and system training. Functional assessments show that the neuroprosthetic hand system allows the subject to perform unilateral and bilateral tasks that were otherwise impossible or were previously performed bimanually. The ability to perform activities of daily living with one hand frees the contralateral upper extremity to be used either for balance which increases the work area, or to stabilize an object allowing manipulation with the instrumented hand. Telephone interviews suggest that the hand system is used on a consistent basis at home and school. This single subject application indicates that a stimulation system designed for adults with C5-6 spinal cord injuries can enhance hand function and facilitate independence in a child with a low level cervical lesion.

Analysis of Decision Making Skills for Large Scale Disaster Response

DTIC Science & Technology

2015-08-21

Capability to influence and collaborate Compassion Teamwork Communication Leadership Provide vision of outcome / set priorities Confidence, courage to make...project evaluates the viability of expanding the use of serious games to augment classroom training, tabletop and full scale exercise, and actual...training, evaluation, analysis, and technology ex- ploration. Those techniques have found successful niches, but their wider applicability faces

Dikin-type algorithms for dextrous grasping force optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buss, M.; Faybusovich, L.; Moore, J.B.

1998-08-01

One of the central issues in dextrous robotic hand grasping is to balance external forces acting on the object and at the same time achieve grasp stability and minimum grasping effort. A companion paper shows that the nonlinear friction-force limit constraints on grasping forces are equivalent to the positive definiteness of a certain matrix subject to linear constraints. Further, compensation of the external object force is also a linear constraint on this matrix. Consequently, the task of grasping force optimization can be formulated as a problem with semidefinite constraints. In this paper, two versions of strictly convex cost functions, onemore » of them self-concordant, are considered. These are twice-continuously differentiable functions that tend to infinity at the boundary of possible definiteness. For the general class of such cost functions, Dikin-type algorithms are presented. It is shown that the proposed algorithms guarantee convergence to the unique solution of the semidefinite programming problem associated with dextrous grasping force optimization. Numerical examples demonstrate the simplicity of implementation, the good numerical properties, and the optimality of the approach.« less

On the road to a neuroprosthetic hand: a novel hand grasp orthosis based on functional electrical stimulation.

PubMed

Leeb, Robert; Gubler, Miguel; Tavella, Michele; Miller, Heather; Del Millan, Jose R

2010-01-01

To patients who have lost the functionality of their hands as a result of a severe spinal cord injury or brain stroke, the development of new techniques for grasping is indispensable for reintegration and independency in daily life. Functional Electrical Stimulation (FES) of residual muscles can reproduce the most dominant grasping tasks and can be initialized by brain signals. However, due to the very complex hand anatomy and current limitations in FES-technology with surface electrodes, these grasp patterns cannot be smoothly executed. In this paper, we present an adaptable passive hand orthosis which is capable of producing natural and smooth movements when coupled with FES. It evenly synchronizes the grasping movements and applied forces on all fingers, allowing for naturalistic gestures and functional grasps of everyday objects. The orthosis is also equipped with a lock, which allows it to remain in the desired position without the need for long-term stimulation. Furthermore, we quantify improvements offered by the orthosis compare them with natural grasps on healthy subjects.

LapSim virtual reality laparoscopic simulator reflects clinical experience in German surgeons.

PubMed

Langelotz, C; Kilian, M; Paul, C; Schwenk, W

2005-11-01

The aim of this study was to analyze the ability of a training module on a virtual laparoscopic simulator to assess surgical experience in laparoscopy. One hundred and fifteen participants at the 120th annual convent of the German surgical society took part in this study. All participants were stratified into two groups, one with laparoscopic experience of less than 50 operations (group 1, n=61) and one with laparoscopic experience of more than 50 laparoscopic operations (group 2, n=54). All subjects completed a laparoscopic training module consisting of five different exercises for navigation, coordination, grasping, cutting and clipping. The time to perform each task was measured, as were the path lengths of the instruments and their respective angles representing the economy of the movements. Results between groups were compared using chi(2) or Mann-Whitney U-test. Group 1 needed more time for completion of the exercises (median 424 s, range 99-1,376 s) than group 2 (median 315 s, range 168-625 s) (P<0.01). Instrument movements were less economic in group 1 with larger angular pathways, e.g. in the cutting exercise (median 352 degrees , range 104-1,628 degrees vs median 204 degrees , range 107-444 degrees , P<0.01), and longer path lengths (each instrument P<0.05). As time for completion of exercises, instrument path lengths and angular paths are indicators of clinical experience, it can be concluded that laparoscopic skills acquired in the operating room transfer into virtual reality. A laparoscopic simulator can serve as an instrument for the assessment of experience in laparoscopic surgery.

Treadmill walking with load carriage increases aortic pressure wave reflection.

PubMed

Ribeiro, Fernando; Oliveira, Nórton L; Pires, Joana; Alves, Alberto J; Oliveira, José

2014-01-01

The study examined the effects of treadmill walking with load carriage on derived measures of central pressure and augmentation index in young healthy subjects. Fourteen male subjects (age 31.0 ± 1.0 years) volunteered in this study. Subjects walked 10 minutes on a treadmill at a speed of 5 km/h carrying no load during one session and a load of 10% of their body weight on both upper limbs in two water carboys with handle during the other session. Pulse wave analysis was performed at rest and immediately after exercise in the radial artery of the right upper limb by applanation tonometry. The main result indicates that walking with load carriage sharply increased augmentation index at 75 bpm (-5.5 ± 2.2 to -1.4 ± 2.2% vs. -5.2 ± 2.8 to -5.5 ± 2.1%, p<0.05), and also induced twice as high increments in central pulse pressure (7.4 ± 1.5 vs. 3.1 ± 1.4 mmHg, p<0.05) and peripheral (20.5 ± 2.7 vs. 10.3 ± 2.5 mmHg, p<0.05) and central systolic pressure (14.7 ± 2.1 vs. 7.4 ± 2.0 mmHg, p<0.05). Walking with additional load of 10% of their body weight (aerobic exercise accompanied by upper limb isometric contraction) increases derived measures of central pressure and augmentation index, an index of wave reflection and arterial stiffness. Copyright © 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

CRUX: A compliant robotic upper-extremity exosuit for lightweight, portable, multi-joint muscular augmentation.

PubMed

Lessard, Steven; Pansodtee, Pattawong; Robbins, Ash; Baltaxe-Admony, Leya Breanna; Trombadore, James M; Teodorescu, Mircea; Agogino, Adrian; Kurniawan, Sri

2017-07-01

Wearable robots can potentially offer their users enhanced stability and strength. These augmentations are ideally designed to actuate harmoniously with the user's movements and provide extra force as needed. The creation of such robots, however, is particularly challenging due to the underlying complexity of the human body. In this paper, we present a compliant, robotic exosuit for upper extremities called CRUX. This exosuit, inspired by tensegrity models of the human arm, features a lightweight (1.3 kg), flexible multi-joint design for portable augmentation. We also illustrate how CRUX maintains the full range of motion of the upper-extremities for its users while providing multi-DoF strength amplification to the major muscles of the arm, as evident by tracking the heart rate of an individual exercising said arm. Exosuits such as CRUX may be useful in physical therapy and in extreme environments where users are expected to exert their bodies to the fullest extent.

Orientation priming of grasping decision for drawings of objects and blocks, and words.

PubMed

Chainay, Hanna; Naouri, Lucie; Pavec, Alice

2011-05-01

This study tested the influence of orientation priming on grasping decisions. Two groups of 20 healthy participants had to select a preferred grasping orientation (horizontal, vertical) based on drawings of everyday objects, geometric blocks or object names. Three priming conditions were used: congruent, incongruent and neutral. The facilitating effects of priming were observed in the grasping decision task for drawings of objects and blocks but not object names. The visual information about congruent orientation in the prime quickened participants' responses but had no effect on response accuracy. The results are discussed in the context of the hypothesis that an object automatically potentiates grasping associated with it, and that the on-line visual information is necessary for grasping potentiation to occur. The possibility that the most frequent orientation of familiar objects might be included in object-action representation is also discussed.

Fast Grasp Contact Computation for a Serial Robot

NASA Technical Reports Server (NTRS)

Hargrave, Brian (Inventor); Shi, Jianying (Inventor); Diftler, Myron A. (Inventor)

2015-01-01

A system includes a controller and a serial robot having links that are interconnected by a joint, wherein the robot can grasp a three-dimensional (3D) object in response to a commanded grasp pose. The controller receives input information, including the commanded grasp pose, a first set of information describing the kinematics of the robot, and a second set of information describing the position of the object to be grasped. The controller also calculates, in a two-dimensional (2D) plane, a set of contact points between the serial robot and a surface of the 3D object needed for the serial robot to achieve the commanded grasp pose. A required joint angle is then calculated in the 2D plane between the pair of links using the set of contact points. A control action is then executed with respect to the motion of the serial robot using the required joint angle.

Comparison of grasping movements made by healthy subjects in a 3-dimensional immersive virtual versus physical environment.

PubMed

Magdalon, Eliane C; Michaelsen, Stella M; Quevedo, Antonio A; Levin, Mindy F

2011-09-01

Virtual reality (VR) technology is being used with increasing frequency as a training medium for motor rehabilitation. However, before addressing training effectiveness in virtual environments (VEs), it is necessary to identify if movements made in such environments are kinematically similar to those made in physical environments (PEs) and the effect of provision of haptic feedback on these movement patterns. These questions are important since reach-to-grasp movements may be inaccurate when visual or haptic feedback is altered or absent. Our goal was to compare kinematics of reaching and grasping movements to three objects performed in an immersive three-dimensional (3D) VE with haptic feedback (cyberglove/grasp system) viewed through a head-mounted display to those made in an equivalent physical environment (PE). We also compared movements in PE made with and without wearing the cyberglove/grasp haptic feedback system. Ten healthy subjects (8 women, 62.1±8.8years) reached and grasped objects requiring 3 different grasp types (can, diameter 65.6mm, cylindrical grasp; screwdriver, diameter 31.6mm, power grasp; pen, diameter 7.5mm, precision grasp) in PE and visually similar virtual objects in VE. Temporal and spatial arm and trunk kinematics were analyzed. Movements were slower and grip apertures were wider when wearing the glove in both the PE and the VE compared to movements made in the PE without the glove. When wearing the glove, subjects used similar reaching trajectories in both environments, preserved the coordination between reaching and grasping and scaled grip aperture to object size for the larger object (cylindrical grasp). However, in VE compared to PE, movements were slower and had longer deceleration times, elbow extension was greater when reaching to the smallest object and apertures were wider for the power and precision grip tasks. Overall, the differences in spatial and temporal kinematics of movements between environments were greater than those due only to wearing the cyberglove/grasp system. Differences in movement kinematics due to the viewing environment were likely due to a lack of prior experience with the virtual environment, an uncertainty of object location and the restricted field-of-view when wearing the head-mounted display. The results can be used to inform the design and disposition of objects within 3D VEs for the study of the control of prehension and for upper limb rehabilitation. Copyright © 2011 Elsevier B.V. All rights reserved.

Effectiveness of exercise in hepatic fat mobilization in non-alcoholic fatty liver disease: Systematic review.

PubMed

Golabi, Pegah; Locklear, Cameron T; Austin, Patrick; Afdhal, Sophie; Byrns, Melinda; Gerber, Lynn; Younossi, Zobair M

2016-07-21

To investigate the efficacy of exercise interventions on hepatic fat mobilization in non-alcoholic fatty liver disease (NAFLD) patients. Ovid-Medline, PubMed, EMBASE and Cochrane database were searched for randomized trials and prospective cohort studies in adults aged ≥ 18 which investigated the effects of at least 8 wk of exercise only or combination with diet on NAFLD from 2010 to 2016. The search terms used to identify articles, in which exercise was clearly described by type, duration, intensity and frequency were: "NASH", "NAFLD", "non-alcoholic steatohepatitis", "non-alcoholic fatty liver disease", "fat", "steatosis", "diet", "exercise", "MR spectroscopy" and "liver biopsy". NAFLD diagnosis, as well as the outcome measures, was confirmed by either hydrogen-magnetic resonance spectroscopy (H-MRS) or biopsy. Trials that included dietary interventions along with exercise were accepted if they met all criteria. Eight studies met selection criteria (6 with exercise only, 2 with diet and exercise with a total of 433 adult participants). Training interventions ranged between 8 and 48 wk in duration with a prescribed exercise frequency of 3 to 7 d per week, at intensities between 45% and 75% of VO2 peak. The most commonly used imaging modality was H-MRS and one study utilized biopsy. The effect of intervention on fat mobilization was 30.2% in the exercise only group and 49.8% in diet and exercise group. There was no difference between aerobic and resistance exercise intervention, although only one study compared the two interventions. The beneficial effects of exercise on intrahepatic triglyceride (IHTG) were seen even in the absence of significant weight loss. Although combining an exercise program with dietary interventions augmented the reduction in IHTG, as well as improved measures of glucose control and/or insulin sensitivity, exercise only significantly decreased hepatic lipid contents. Prescribed exercise in subjects with NAFLD reduces IHTG independent of dietary intervention. Diet and exercise was more effective than exercise alone in reducing IHTG.

Multiple parietal-frontal pathways mediate grasping in macaque monkeys

PubMed Central

Gharbawie, Omar A.; Stepniewska, Iwona; Qi, Huixin; Kaas, Jon H.

2011-01-01

The nodes of a parietal-frontal pathway that mediates grasping in primates are in anterior intraparietal area (AIP) and ventral premotor cortex (PMv). Nevertheless, multiple somatosensory and motor representations of the hand, respectively in parietal and frontal cortex, suggest that additional pathways remain unrealized. We explored this possibility in macaque monkeys by injecting retrograde tracers into grasp zones identified in M1, PMv, and area 2 with long train electrical stimulation. The M1 grasp zone was densely connected with other frontal cortex motor regions. The remainder of the connections originated from somatosensory areas 3a and S2/PV, and from the medial bank and fundus of the intraparietal sulcus (IPS). The PMv grasp zone was also densely connected with frontal cortex motor regions, albeit to a lesser extent than the M1 grasp zone. The remainder of the connections originated from areas S2/PV and aspects of the inferior parietal lobe such as PF, PFG, AIP, and the tip of the IPS. The area 2 grasp zone was densely connected with the hand representations of somatosensory areas 3b, 1, and S2/PV. The remainder of the connections was with areas 3a and 5 and the medial bank and fundus of the IPS. Connections with frontal cortex were relatively weak and concentrated in caudal M1. Thus, the three grasp zones may be nodes of parallel parietal-frontal pathways. Differential points of origin and termination of each pathway suggest varying functional specializations. Direct and indirect connections between those parietal-frontal pathways likely coordinate their respective functions into an accurate grasp. PMID:21832196

Analysis of Structures with Rotating, Flexible Substructures Applied to Rotorcraft Aeroelasticity in GRASP (General Rotorcraft Aeromechanical Stability Program),

DTIC Science & Technology

1987-01-01

two nodes behave identically. In GRASP, these constraints are entirely invisible from the user’s point of view. GRASP (Recall that the Levi - Civita ...virtual rotation GRASP is the first program implementing a new methodWl( = Levi -Ciudta symbol op for dynamic analysis of structures, parts of which may...natural coordinatization of sis for this methodology, which incorporates body flexibility components. with the large discrete motions previously

Grasping Force Control for a Robotic Hand by Slip Detection Using Developed Micro Laser Doppler Velocimeter

PubMed Central

Nogami, Hirofumi; Higurashi, Eiji; Sawada, Renshi

2018-01-01

The purpose of this paper is to show the feasibility of grasping force control by feeding back signals of the developed micro-laser Doppler velocimeter (μ-LDV) and by discriminating whether a grasped object is slipping or not. LDV is well known as a high response surface velocity sensor which can measure various surfaces—such as metal, paper, film, and so on—thus suggesting the potential application of LDV as a slip sensor for grasping various objects. However, the use of LDV as a slip sensor has not yet been reported because the size of LDVs is too large to be installed on a robotic fingertip. We have solved the size problem and enabled the performance of a feasibility test with a few-millimeter-scale LDV referred to as micro-LDV (μ-LDV) by modifying the design which was adopted from MEMS (microelectromechanical systems) fabrication process. In this paper, by applying our developed μ-LDV as a slip sensor, we have successfully demonstrated grasping force control with three target objects—aluminum block, wood block, and white acrylic block—considering that various objects made of these materials can be found in homes and factories, without grasping force feedback. We provide proofs that LDV is a new promising candidate slip sensor for grasping force control to execute target grasping. PMID:29360799

Correlations between grasp-reflex strengths and serum thyroid-hormone levels depending upon sex and familial sinistrality in human neonates: importance of genetically predetermined cerebral organization.

PubMed

Tan, U

1994-03-01

Relations of grasp-reflex strengths to serum free-thyroid hormone levels were studied in human neonates. In right-dominant (RH) males and females without familial sinistrality (-FS), grasp-reflex strengths from right (R) and left (L) inversely correlated with serum triiodothyronine (T3). In RH, +FS males, grasp-reflex strengths from R and L hands directly correlated with T3 (no correlations in RH, +FS females). There was no significant correlation between grasp reflex and T3 in non-right-handed (NRH), -FS neonates. In NRH +FS neonates, there was a significant negative linear correlation between grasp reflex from left and T3 only in NRH, +FS males. The following correlations were found between grasp reflex and thyroxine (T4): direct relation in RH, +FS males and females; inverse relation in NRH, -FS females only for the right hand; inverse correlations in NRH, +FS females. The R-L grasp reflex directly correlated with T3 in RH, -FS males, and inversely correlated with T3 in RH, -FS females (no significant correlations in others). These results indicated that thyroid hormones may influence cerebral maturation and lateralization differentially according to genetically predetermined cerebral organization. The generalizations of the hormonal effects on, at least, cerebral functioning would be wrong, if the genetically predetermined main features of the brain are neglected.

Development of a non-invasive, multifunctional grasp neuroprosthesis and its evaluation in an individual with a high spinal cord injury.

PubMed

Rupp, Rüdiger; Kreilinger, Alex; Rohm, Martin; Kaiser, Vera; Müller-Putz, Gernot R

2012-01-01

Over the last decade the improvement of a missing hand function by application of neuroprostheses in particular the implantable Freehand system has been successfully shown in high spinal cord injured individuals. The clinically proven advantages of the Freehand system is its ease of use, the reproducible generation of two distinct functional grasp patterns and an analog control scheme based on movements of the contralateral shoulder. However, after the Freehand system is not commercially available for more than ten years, alternative grasp neuroprosthesis with a comparable functionality are still missing. Therefore, the aim of this study was to develop a non-invasive neuroprosthesis and to show that a degree of functional restoration can be provided to end users comparable to implanted devices. By introduction of an easy to handle forearm electrode sleeve the reproducible generation of two grasp patterns has been achieved. Generated grasp forces of the palmar grasp are in the range of the implanted system. Though pinch force of the lateral grasp is significantly lower, it can effectively used by a tetraplegic subject to perform functional tasks. The non-invasive grasp neuroprosthesis developed in this work may serve as an easy to apply and inexpensive way to restore a missing hand and finger function at any time after spinal cord injury.

Attention and reach-to-grasp movements in Parkinson's disease.

PubMed

Lu, Cathy; Bharmal, Aamir; Kiss, Zelma H; Suchowersky, Oksana; Haffenden, Angela M

2010-08-01

The role of attention in grasping movements directed at common objects has not been examined in Parkinson's disease (PD), though these movements are critical to activities of daily living. Our primary objective was to determine whether patients with PD demonstrate automaticity in grasping movements directed toward common objects. Automaticity is assumed when tasks can be performed with little or no interference from concurrent tasks. Grasping performance in three patient groups (newly diagnosed, moderate, and advanced/surgically treated PD) on and off of their medication or deep brain stimulation was compared to performance in an age-matched control group. Automaticity was demonstrated by the absence of a decrement in grasping performance when attention was consumed by a concurrent spatial-visualization task. Only the control group and newly diagnosed PD group demonstrated automaticity in their grasping movements. The moderate and advanced PD groups did not demonstrate automaticity. Furthermore, the well-known effects of pharmacotherapy and surgical intervention on movement speed and muscle activation patterns did not appear to reduce the impact of attention-demanding tasks on grasping movements in those with moderate to advanced PD. By the moderate stage of PD, grasping is an attention-demanding process; this change is not ameliorated by dopaminergic or surgical treatments. These findings have important implications for activities of daily living, as devoting attention to the simplest of daily tasks would interfere with complex activities and potentially exacerbate fatigue.

The functional subdivision of the visual brain: Is there a real illusion effect on action? A multi-lab replication study.

PubMed

Kopiske, Karl K; Bruno, Nicola; Hesse, Constanze; Schenk, Thomas; Franz, Volker H

2016-06-01

It has often been suggested that visual illusions affect perception but not actions such as grasping, as predicted by the "two-visual-systems" hypothesis of Milner and Goodale (1995, The Visual Brain in Action, Oxford University press). However, at least for the Ebbinghaus illusion, relevant studies seem to reveal a consistent illusion effect on grasping (Franz & Gegenfurtner, 2008. Grasping visual illusions: consistent data and no dissociation. Cognitive Neuropsychology). Two interpretations are possible: either grasping is not immune to illusions (arguing against dissociable processing mechanisms for vision-for-perception and vision-for-action), or some other factors modulate grasping in ways that mimic a vision-for perception effect in actions. It has been suggested that one such factor may be obstacle avoidance (Haffenden Schiff & Goodale, 2001. The dissociation between perception and action in the Ebbinghaus illusion: nonillusory effects of pictorial cues on grasp. Current Biology, 11, 177-181). In four different labs (total N = 144), we conducted an exact replication of previous studies suggesting obstacle avoidance mechanisms, implementing conditions that tested grasping as well as multiple perceptual tasks. This replication was supplemented by additional conditions to obtain more conclusive results. Our results confirm that grasping is affected by the Ebbinghaus illusion and demonstrate that this effect cannot be explained by obstacle avoidance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Similar Cerebral Motor Plans for Real and Virtual Actions

PubMed Central

Bozzacchi, Chiara; Giusti, Maria Assunta; Pitzalis, Sabrina; Spinelli, Donatella; Di Russo, Francesco

2012-01-01

A simple movement, such as pressing a button, can acquire different meanings by producing different consequences, such as starting an elevator or switching a TV channel. We evaluated whether the brain activity preceding a simple action is modulated by the expected consequences of the action itself. To further this aim, the motor-related cortical potentials were compared during two key-press actions that were identical from the kinematics point of view but different in both meaning and consequences. In one case (virtual grasp), the key-press started a video clip showing a hand moving toward a cup and grasping it; in the other case, the key-press did not produce any consequence (key-press). A third condition (real grasp) was also compared, in which subjects actually grasped the cup, producing the same action presented in the video clip. Data were collected from fifteen subjects. The results showed that motor preparation for virtual grasp (starting 3 s before the movement onset) was different from that of the key-press and similar to the real grasp preparation–as if subjects had to grasp the cup in person. In particular, both virtual and real grasp presented a posterior parietal negativity preceding activity in motor and pre-motor areas. In summary, this finding supports the hypothesis that motor preparation is affected by the meaning of the action, even when the action is only virtual. PMID:23112847

Intestinal epithelial barrier function and tight junction proteins with heat and exercise

PubMed Central

Zuhl, Micah N.; Moseley, Pope L.

2015-01-01

A single layer of enterocytes and tight junctions (intercellular multiprotein complexes) form the intestinal epithelial barrier that controls transport of molecules through transcellular and paracellular pathways. A dysfunctional or “leaky” intestinal tight junction barrier allows augmented permeation of luminal antigens, endotoxins, and bacteria into the blood stream. Various substances and conditions have been shown to affect the maintenance of the intestinal epithelial tight junction barrier. The primary focus of the present review is to analyze the effects of exertional or nonexertional (passive hyperthermia) heat stress on tight junction barrier function in in vitro and in vivo (animals and humans) models. Our secondary focus is to review changes in tight junction proteins in response to exercise or hyperthermic conditions. Finally, we discuss some pharmacological or nutritional interventions that may affect the cellular mechanisms involved in maintaining homeostasis of the intestinal epithelial tight junction barrier during heat stress or exercise. PMID:26359485

Intestinal epithelial barrier function and tight junction proteins with heat and exercise.

PubMed

Dokladny, Karol; Zuhl, Micah N; Moseley, Pope L

2016-03-15

A single layer of enterocytes and tight junctions (intercellular multiprotein complexes) form the intestinal epithelial barrier that controls transport of molecules through transcellular and paracellular pathways. A dysfunctional or "leaky" intestinal tight junction barrier allows augmented permeation of luminal antigens, endotoxins, and bacteria into the blood stream. Various substances and conditions have been shown to affect the maintenance of the intestinal epithelial tight junction barrier. The primary focus of the present review is to analyze the effects of exertional or nonexertional (passive hyperthermia) heat stress on tight junction barrier function in in vitro and in vivo (animals and humans) models. Our secondary focus is to review changes in tight junction proteins in response to exercise or hyperthermic conditions. Finally, we discuss some pharmacological or nutritional interventions that may affect the cellular mechanisms involved in maintaining homeostasis of the intestinal epithelial tight junction barrier during heat stress or exercise. Copyright © 2016 the American Physiological Society.

Real-time vision, tactile cues, and visual form agnosia: removing haptic feedback from a “natural” grasping task induces pantomime-like grasps

PubMed Central

Whitwell, Robert L.; Ganel, Tzvi; Byrne, Caitlin M.; Goodale, Melvyn A.

2015-01-01

Investigators study the kinematics of grasping movements (prehension) under a variety of conditions to probe visuomotor function in normal and brain-damaged individuals. “Natural” prehensile acts are directed at the goal object and are executed using real-time vision. Typically, they also entail the use of tactile, proprioceptive, and kinesthetic sources of haptic feedback about the object (“haptics-based object information”) once contact with the object has been made. Natural and simulated (pantomimed) forms of prehension are thought to recruit different cortical structures: patient DF, who has visual form agnosia following bilateral damage to her temporal-occipital cortex, loses her ability to scale her grasp aperture to the size of targets (“grip scaling”) when her prehensile movements are based on a memory of a target previewed 2 s before the cue to respond or when her grasps are directed towards a visible virtual target but she is denied haptics-based information about the target. In the first of two experiments, we show that when DF performs real-time pantomimed grasps towards a 7.5 cm displaced imagined copy of a visible object such that her fingers make contact with the surface of the table, her grip scaling is in fact quite normal. This finding suggests that real-time vision and terminal tactile feedback are sufficient to preserve DF’s grip scaling slopes. In the second experiment, we examined an “unnatural” grasping task variant in which a tangible target (along with any proxy such as the surface of the table) is denied (i.e., no terminal tactile feedback). To do this, we used a mirror-apparatus to present virtual targets with and without a spatially coincident copy for the participants to grasp. We compared the grasp kinematics from trials with and without terminal tactile feedback to a real-time-pantomimed grasping task (one without tactile feedback) in which participants visualized a copy of the visible target as instructed in our laboratory in the past. Compared to natural grasps, removing tactile feedback increased RT, slowed the velocity of the reach, reduced in-flight grip aperture, increased the slopes relating grip aperture to target width, and reduced the final grip aperture (FGA). All of these effects were also observed in the real time-pantomime grasping task. These effects seem to be independent of those that arise from using the mirror in general as we also compared grasps directed towards virtual targets to those directed at real ones viewed directly through a pane of glass. These comparisons showed that the grasps directed at virtual targets increased grip aperture, slowed the velocity of the reach, and reduced the slopes relating grip aperture to the widths of the target. Thus, using the mirror has real consequences on grasp kinematics, reflecting the importance of task-relevant sources of online visual information for the programming and updating of natural prehensile movements. Taken together, these results provide compelling support for the view that removing terminal tactile feedback, even when the grasps are target-directed, induces a switch from real-time visual control towards one that depends more on visual perception and cognitive supervision. Providing terminal tactile feedback and real-time visual information can evidently keep the dorsal visuomotor system operating normally for prehensile acts. PMID:25999834

Real-time vision, tactile cues, and visual form agnosia: removing haptic feedback from a "natural" grasping task induces pantomime-like grasps.

PubMed

Whitwell, Robert L; Ganel, Tzvi; Byrne, Caitlin M; Goodale, Melvyn A

2015-01-01

Investigators study the kinematics of grasping movements (prehension) under a variety of conditions to probe visuomotor function in normal and brain-damaged individuals. "Natural" prehensile acts are directed at the goal object and are executed using real-time vision. Typically, they also entail the use of tactile, proprioceptive, and kinesthetic sources of haptic feedback about the object ("haptics-based object information") once contact with the object has been made. Natural and simulated (pantomimed) forms of prehension are thought to recruit different cortical structures: patient DF, who has visual form agnosia following bilateral damage to her temporal-occipital cortex, loses her ability to scale her grasp aperture to the size of targets ("grip scaling") when her prehensile movements are based on a memory of a target previewed 2 s before the cue to respond or when her grasps are directed towards a visible virtual target but she is denied haptics-based information about the target. In the first of two experiments, we show that when DF performs real-time pantomimed grasps towards a 7.5 cm displaced imagined copy of a visible object such that her fingers make contact with the surface of the table, her grip scaling is in fact quite normal. This finding suggests that real-time vision and terminal tactile feedback are sufficient to preserve DF's grip scaling slopes. In the second experiment, we examined an "unnatural" grasping task variant in which a tangible target (along with any proxy such as the surface of the table) is denied (i.e., no terminal tactile feedback). To do this, we used a mirror-apparatus to present virtual targets with and without a spatially coincident copy for the participants to grasp. We compared the grasp kinematics from trials with and without terminal tactile feedback to a real-time-pantomimed grasping task (one without tactile feedback) in which participants visualized a copy of the visible target as instructed in our laboratory in the past. Compared to natural grasps, removing tactile feedback increased RT, slowed the velocity of the reach, reduced in-flight grip aperture, increased the slopes relating grip aperture to target width, and reduced the final grip aperture (FGA). All of these effects were also observed in the real time-pantomime grasping task. These effects seem to be independent of those that arise from using the mirror in general as we also compared grasps directed towards virtual targets to those directed at real ones viewed directly through a pane of glass. These comparisons showed that the grasps directed at virtual targets increased grip aperture, slowed the velocity of the reach, and reduced the slopes relating grip aperture to the widths of the target. Thus, using the mirror has real consequences on grasp kinematics, reflecting the importance of task-relevant sources of online visual information for the programming and updating of natural prehensile movements. Taken together, these results provide compelling support for the view that removing terminal tactile feedback, even when the grasps are target-directed, induces a switch from real-time visual control towards one that depends more on visual perception and cognitive supervision. Providing terminal tactile feedback and real-time visual information can evidently keep the dorsal visuomotor system operating normally for prehensile acts.

Emergent coordination underlying learning to reach to grasp with a brain-machine interface.

PubMed

Vaidya, Mukta; Balasubramanian, Karthikeyan; Southerland, Joshua; Badreldin, Islam; Eleryan, Ahmed; Shattuck, Kelsey; Gururangan, Suchin; Slutzky, Marc; Osborne, Leslie; Fagg, Andrew; Oweiss, Karim; Hatsopoulos, Nicholas G

2018-04-01

The development of coordinated reach-to-grasp movement has been well studied in infants and children. However, the role of motor cortex during this development is unclear because it is difficult to study in humans. We took the approach of using a brain-machine interface (BMI) paradigm in rhesus macaques with prior therapeutic amputations to examine the emergence of novel, coordinated reach to grasp. Previous research has shown that after amputation, the cortical area previously involved in the control of the lost limb undergoes reorganization, but prior BMI work has largely relied on finding neurons that already encode specific movement-related information. In this study, we taught macaques to cortically control a robotic arm and hand through operant conditioning, using neurons that were not explicitly reach or grasp related. Over the course of training, stereotypical patterns emerged and stabilized in the cross-covariance between the reaching and grasping velocity profiles, between pairs of neurons involved in controlling reach and grasp, and to a comparable, but lesser, extent between other stable neurons in the network. In fact, we found evidence of this structured coordination between pairs composed of all combinations of neurons decoding reach or grasp and other stable neurons in the network. The degree of and participation in coordination was highly correlated across all pair types. Our approach provides a unique model for studying the development of novel, coordinated reach-to-grasp movement at the behavioral and cortical levels. NEW & NOTEWORTHY Given that motor cortex undergoes reorganization after amputation, our work focuses on training nonhuman primates with chronic amputations to use neurons that are not reach or grasp related to control a robotic arm to reach to grasp through the use of operant conditioning, mimicking early development. We studied the development of a novel, coordinated behavior at the behavioral and cortical level, and the neural plasticity in M1 associated with learning to use a brain-machine interface.

Design and fabrication of robotic gripper for grasping in minimizing contact force

NASA Astrophysics Data System (ADS)

Heidari, Hamidreza; Pouria, Milad Jafary; Sharifi, Shahriar; Karami, Mahmoudreza

2018-03-01

This paper presents a new method to improve the kinematics of robot gripper for grasping in unstructured environments, such as space operations. The robot gripper is inspired from the human hand and kept the hand design close to the structure of human fingers to provide successful grasping capabilities. The main goal is to improve kinematic structure of gripper to increase the grasping capability of large objects, decrease the contact forces and makes a successful grasp of various objects in unstructured environments. This research will describe the development of a self-adaptive and reconfigurable robotic hand for space operations through mechanical compliance which is versatile, robust and easy to control. Our model contains two fingers, two-link and three-link, with combining a kinematic model of thumb index. Moreover, some experimental tests are performed to examine the effectiveness of the hand-made in real, unstructured tasks. The results represent that the successful grasp range is improved about 30% and the contact forces is reduced approximately 10% for a wide range of target object size. According to the obtained results, the proposed approach provides an accommodative kinematic model which makes the better grasping capability by fingers geometries for a robot gripper.

Development and assessment of a hand assist device: GRIPIT.

PubMed

Kim, Byungchul; In, Hyunki; Lee, Dae-Young; Cho, Kyu-Jin

2017-02-21

Although various hand assist devices have been commercialized for people with paralysis, they are somewhat limited in terms of tool fixation and device attachment method. Hand exoskeleton robots allow users to grasp a wider range of tools but are heavy, complicated, and bulky owing to the presence of numerous actuators and controllers. The GRIPIT hand assist device overcomes the limitations of both conventional devices and exoskeleton robots by providing improved tool fixation and device attachment in a lightweight and compact device. GRIPIT has been designed to assist tripod grasp for people with spinal cord injury because this grasp posture is frequently used in school and offices for such activities as writing and grasping small objects. The main development objective of GRIPIT is to assist users to grasp tools with their own hand using a lightweight, compact assistive device that is manually operated via a single wire. GRIPIT consists of only a glove, a wire, and a small structure that maintains tendon tension to permit a stable grasp. The tendon routing points are designed to apply force to the thumb, index finger, and middle finger to form a tripod grasp. A tension-maintenance structure sustains the grasp posture with appropriate tension. Following device development, four people with spinal cord injury were recruited to verify the writing performance of GRIPIT compared to the performance of a conventional penholder and handwriting. Writing was chosen as the assessment task because it requires a tripod grasp, which is one of the main performance objectives of GRIPIT. New assessment, which includes six different writing tasks, was devised to measure writing ability from various viewpoints including both qualitative and quantitative methods, while most conventional assessments include only qualitative methods or simple time measuring assessments. Appearance, portability, difficulty of wearing, difficulty of grasping the subject, writing sensation, fatigability, and legibility were measured to assess qualitative performance while writing various words and sentences. Results showed that GRIPIT is relatively complicated to wear and use compared to a conventional assist device but has advantages for writing sensation, fatigability, and legibility because it affords sufficient grasp force during writing. Two quantitative performance factors were assessed, accuracy of writing and solidity of writing. To assess accuracy of writing, we asked subjects to draw various figures under given conditions. To assess solidity of writing, pen tip force and the angle variation of the pen were measured. Quantitative evaluation results showed that GRIPIT helps users to write accurately without pen shakes even high force is applied on the pen. Qualitative and quantitative results were better when subjects used GRIPIT than when they used the conventional penholder, mainly because GRIPIT allowed them to exert a higher grasp force. Grasp force is important because disabled people cannot control their fingers and thus need to move their entire arm to write, while non-disabled people only need to move their fingers to write. The tension-maintenance structure developed for GRIPIT provides appropriate grasp force and moment balance on the user's hand, but the other writing method only fixes the pen using friction force or requires the user's arm to generate a grasp force.

Neurobiological markers of exercise-related brain plasticity in older adults

PubMed Central

Voss, Michelle W.; Erickson, Kirk I.; Prakash, Ruchika Shaurya; Chaddock, Laura; Kim, Jennifer S.; Alves, Heloisa; Szabo, Amanda; White, Siobhan M.; Wójcicki, Thomas R.; Mailey, Emily L.; Olson, Erin A.; Gothe, Neha; Potter, Vicki V.; Martin, Stephen A.; Pence, Brandt D.; Cook, Marc D.; Woods, Jeffrey A.; McAuley, Edward; Kramer, Arthur F.

2012-01-01

The current study examined how a randomized one-year aerobic exercise program for healthy older adults would affect serum levels of brain-derived neurotrophic factor (BDNF), insulin-like growth factor type 1 (IGF-1), and vascular endothelial growth factor (VEGF) - putative markers of exercise-induced benefits on brain function. The study also examined whether (a) change in the concentration of these growth factors was associated with alterations in functional connectivity following exercise, and (b) the extent to which pre-intervention growth factor levels were associated with training-related changes in functional connectivity. In 65 participants (mean age = 66.4), we found that although there were no group-level changes in growth factors as a function of the intervention, increased temporal lobe connectivity between the bilateral parahippocampus and the bilateral middle temporal gyrus was associated with increased BDNF, IGF-1, and VEGF for an aerobic walking group but not for a non-aerobic control group, and greater pre-intervention VEGF was associated with greater training-related increases in this functional connection. Results are consistent with animal models of exercise and the brain, but are the first to show in humans that exercise-induced increases in temporal lobe functional connectivity are associated with changes in growth factors and may be augmented by greater baseline VEGF. PMID:23123199

Potential benefits of exercise on blood pressure and vascular function.

PubMed

Pal, Sebely; Radavelli-Bagatini, Simone; Ho, Suleen

2013-01-01

Physical activity seems to enhance cardiovascular fitness during the course of the lifecycle, improve blood pressure, and is associated with decreased prevalence of hypertension and coronary heart disease. It may also delay or prevent age-related increases in arterial stiffness. It is unclear if specific exercise types (aerobic, resistance, or combination) have a better effect on blood pressure and vascular function. This review was written based on previous original articles, systematic reviews, and meta-analyses indexed on PubMed from years 1975 to 2012 to identify studies on different types of exercise and the associations or effects on blood pressure and vascular function. In summary, aerobic exercise (30 to 40 minutes of training at 60% to 85% of predicted maximal heart rate, most days of the week) appears to significantly improve blood pressure and reduce augmentation index. Resistance training (three to four sets of eight to 12 repetitions at 10 repetition maximum, 3 days a week) appears to significantly improve blood pressure, whereas combination exercise training (15 minutes of aerobic and 15 minutes of resistance, 5 days a week) is beneficial to vascular function, but at a lower scale. Aerobic exercise seems to better benefit blood pressure and vascular function. Copyright © 2013 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

Grasp planning under uncertainty

NASA Technical Reports Server (NTRS)

Erkmen, A. M.; Stephanou, H. E.

1989-01-01

The planning of dexterous grasps for multifingered robot hands operating in uncertain environments is covered. A sensor-based approach to the planning of a reach path prior to grasping is first described. An on-line, joint space finger path planning algorithm for the enclose phase of grasping was then developed. The algorithm minimizes the impact momentum of the hand. It uses a Preshape Jacobian matrix to map task-level hand preshape requirements into kinematic constraints. A master slave scheme avoids inter-finger collisions and reduces the dimensionality of the planning problem.

Clearing a Pile of Unknown Objects using Interactive Perception

DTIC Science & Technology

2012-11-01

blocks and the shampoo . The robot now decides to grasp the bottle of shampoo . Next, the tissue box and the chunk of wood are pushed and grasped. The...20 seconds. Poking an object requires 12 (a) Initial pile (b) Poking macaroni box (c) After poking (d) Grasping shampoo (e) After grasping (f) Pooking...objects: a tissue box, a chunk of wood, a bottle of shampoo , a box of macaroni, and toy blocks. The algorithm switches between pushing to verify

An Analytical Evaluation of Contingency Contracting Operations in Iraq and Afghanistan: Capturing Critical Corporate Knowledge for the Future

DTIC Science & Technology

2013-01-07

Contingency Operations Task Force, 2011, p. 4)...........................68  Figure 25.  Original Organizational Makeup for the CASO (After Deputy...Workforce CAP Civilian Augmentation Program CAP Crisis Action Planning CASO Contingency Acquisition Support Office CBP Capability-Based...its inclusion in joint exercises;  Identify and assign responsibilities to institutionalize OCS lesson development, analysis, documentation and use

Use of Case-Based or Hands-On Laboratory Exercises with Physiology Lectures Improves Knowledge Retention, but Veterinary Medicine Students Prefer Case-Based Activities

ERIC Educational Resources Information Center

McFee, Renee M.; Cupp, Andrea S.; Wood, Jennifer R.

2018-01-01

Didactic lectures are prevalent in physiology courses within veterinary medicine programs, but more active learning methods have also been utilized. Our goal was to identify the most appropriate learning method to augment the lecture component of our physiology course. We hypothesized that case-based learning would be well received by students and…

Using "Saccharomyces cerevisiae" to Test the Mutagenicity of Household Compounds: An Open Ended Hypothesis-Driven Teaching Lab

ERIC Educational Resources Information Center

Marshall, Pamela A.

2007-01-01

In our Fundamentals of Genetics lab, students perform a wide variety of labs to reinforce and extend the topics covered in lecture. I developed an active-learning lab to augment the lecture topic of mutagenesis. In this lab exercise, students determine if a compound they bring from home is a mutagen. Students are required to read extensive…

The influence of object shape and center of mass on grasp and gaze

PubMed Central

Desanghere, Loni; Marotta, Jonathan J.

2015-01-01

Recent experiments examining where participants look when grasping an object found that fixations favor the eventual index finger landing position on the object. Even though the act of picking up an object must involve complex high-level computations such as the visual analysis of object contours, surface properties, knowledge of an object’s function and center of mass (COM) location, these investigations have generally used simple symmetrical objects – where COM and horizontal midline overlap. Less research has been aimed at looking at how variations in object properties, such as differences in curvature and changes in COM location, affect visual and motor control. The purpose of this study was to examine grasp and fixation locations when grasping objects whose COM was positioned to the left or right of the objects horizontal midline (Experiment 1) and objects whose COM was moved progressively further from the midline of the objects based on the alteration of the object’s shape (Experiment 2). Results from Experiment 1 showed that object COM position influenced fixation locations and grasp locations differently, with fixations not as tightly linked to index finger grasp locations as was previously reported with symmetrical objects. Fixation positions were also found to be more central on the non-symmetrical objects. This difference in gaze position may provide a more holistic view, which would allow both index finger and thumb positions to be monitored while grasping. Finally, manipulations of COM distance (Experiment 2) exerted marked effects on the visual analysis of the objects when compared to its influence on grasp locations, with fixation locations more sensitive to these manipulations. Together, these findings demonstrate how object features differentially influence gaze vs. grasp positions during object interaction. PMID:26528207

Discharge of primate magnocellular red nucleus neurons during reaching to grasp in different spatial locations.

PubMed

van Kan, Peter L E; McCurdy, Martha L

2002-01-01

Reaching to grasp is of fundamental importance to primate motor behavior. One descending motor pathway that contributes to the control of this behavior is the rubrospinal tract. An important source of origin of the rubrospinal tract is the magnocellular red nucleus (RNm). Forelimb RNm neurons discharge vigorously during reach-to-grasp movements. RNm discharge is important for hand use, as coordinated whole-limb movements without hand use are not associated with strong discharge. Because RNm is functionally linked to muscles of the entire forelimb, RNm discharge may also contribute to use of the proximal limb that accompanies hand use. If RNm contributes to proximal limb use, we predict discharge to differ for reaches that differ in proximal limb involvement but require the same grasp. We tested this prediction by measuring discharge of individual RNm neurons while monkeys reached to grasp objects in four spatial locations in front of them. The animals reached from the waist to locations to the left, right, above, and below the shoulder of the "reaching" limb. RNm neurons of our sample were activated strongly during reach-to-grasp, and discharge of a third of the neurons tested depended on the spatial location of the object grasped. Discharge of RNm neurons and EMG activity of many of the distal and proximal forelimb muscles we tested were larger for reaching to grasp in the upper and/or right than lower and left target locations. Based on comparisons of each individual neuron's discharge patterns during reaches with and without preshaping the hand, we conclude that target location-dependent modulations in discharge rate of the majority of RNm neurons whose discharge differed for reaching to grasp in the four target locations contributed to aspects of hand preshaping that covaried with reach direction.

Decoding natural reach-and-grasp actions from human EEG

NASA Astrophysics Data System (ADS)

Schwarz, Andreas; Ofner, Patrick; Pereira, Joana; Ioana Sburlea, Andreea; Müller-Putz, Gernot R.

2018-02-01

Objective. Despite the high number of degrees of freedom of the human hand, most actions of daily life can be executed incorporating only palmar, pincer and lateral grasp. In this study we attempt to discriminate these three different executed reach-and-grasp actions utilizing their EEG neural correlates. Approach. In a cue-guided experiment, 15 healthy individuals were asked to perform these actions using daily life objects. We recorded 72 trials for each reach-and-grasp condition and from a no-movement condition. Main results. Using low-frequency time domain features from 0.3 to 3 Hz, we achieved binary classification accuracies of 72.4%, STD  ±  5.8% between grasp types, for grasps versus no-movement condition peak performances of 93.5%, STD  ±  4.6% could be reached. In an offline multiclass classification scenario which incorporated not only all reach-and-grasp actions but also the no-movement condition, the highest performance could be reached using a window of 1000 ms for feature extraction. Classification performance peaked at 65.9%, STD  ±  8.1%. Underlying neural correlates of the reach-and-grasp actions, investigated over the primary motor cortex, showed significant differences starting from approximately 800 ms to 1200 ms after the movement onset which is also the same time frame where classification performance reached its maximum. Significance. We could show that it is possible to discriminate three executed reach-and-grasp actions prominent in people’s everyday use from non-invasive EEG. Underlying neural correlates showed significant differences between all tested conditions. These findings will eventually contribute to our attempt of controlling a neuroprosthesis in a natural and intuitive way, which could ultimately benefit motor impaired end users in their daily life actions.

Optimization and validation of accelerated golden-angle radial sparse MRI reconstruction with self-calibrating GRAPPA operator gridding.

PubMed

Benkert, Thomas; Tian, Ye; Huang, Chenchan; DiBella, Edward V R; Chandarana, Hersh; Feng, Li

2018-07-01

Golden-angle radial sparse parallel (GRASP) MRI reconstruction requires gridding and regridding to transform data between radial and Cartesian k-space. These operations are repeatedly performed in each iteration, which makes the reconstruction computationally demanding. This work aimed to accelerate GRASP reconstruction using self-calibrating GRAPPA operator gridding (GROG) and to validate its performance in clinical imaging. GROG is an alternative gridding approach based on parallel imaging, in which k-space data acquired on a non-Cartesian grid are shifted onto a Cartesian k-space grid using information from multicoil arrays. For iterative non-Cartesian image reconstruction, GROG is performed only once as a preprocessing step. Therefore, the subsequent iterative reconstruction can be performed directly in Cartesian space, which significantly reduces computational burden. Here, a framework combining GROG with GRASP (GROG-GRASP) is first optimized and then compared with standard GRASP reconstruction in 22 prostate patients. GROG-GRASP achieved approximately 4.2-fold reduction in reconstruction time compared with GRASP (∼333 min versus ∼78 min) while maintaining image quality (structural similarity index ≈ 0.97 and root mean square error ≈ 0.007). Visual image quality assessment by two experienced radiologists did not show significant differences between the two reconstruction schemes. With a graphics processing unit implementation, image reconstruction time can be further reduced to approximately 14 min. The GRASP reconstruction can be substantially accelerated using GROG. This framework is promising toward broader clinical application of GRASP and other iterative non-Cartesian reconstruction methods. Magn Reson Med 80:286-293, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Branched-Chain Amino Acid Supplementation in Combination with Voluntary Running Improves Body Composition in Female C57BL/6 Mice

PubMed Central

Platt, Kristen M.; Charnigo, Richard J.; Shertzer, Howard G.; Pearson, Kevin J.

2016-01-01

Exercise is an inexpensive intervention that may be used to reduce obesity and its consequences. In addition, many individuals who regularly exercise utilize dietary supplements to enhance their exercise routine and to accelerate fat loss or increase lean mass. Branched-chain amino acids (BCAAs) are a popular supplement and have been shown to produce a number of beneficial effects in rodent models and humans. Therefore, we hypothesized that BCAA supplementation would protect against high fat diet (HFD)-induced glucose intolerance and obesity in mice with and without access to exercise. We subjected 80 female C57BL/6 mice to a paradigm of HFD feeding, exercise in the form of voluntary wheel running, and BCAA supplementation in the drinking water for 16 weeks (n = 10 per group). Body weight was monitored weekly, while food and water consumption were recorded twice weekly. During the 5th, 10th, and 15th weeks of treatment, glucose tolerance and body composition were analyzed. Exercise significantly improved glucose tolerance in both control-fed and HFD-fed mice. BCAA supplementation, however, did not significantly alter glucose tolerance in any treatment group. While BCAA supplements did not improve lean to fat mass ratio in sedentary mice, it significantly augmented the effects of exercise on this parameter. PMID:26716948

Dietary thiols in exercise: oxidative stress defence, exercise performance, and adaptation.

PubMed

McLeay, Yanita; Stannard, Stephen; Houltham, Stuart; Starck, Carlene

2017-01-01

Endurance athletes are susceptible to cellular damage initiated by excessive levels of aerobic exercise-produced reactive oxygen species (ROS). Whilst ROS can contribute to the onset of fatigue, there is increasing evidence that they play a crucial role in exercise adaptations. The use of antioxidant supplements such as vitamin C and E in athletes is common; however, their ability to enhance performance and facilitate recovery is controversial, with many studies suggesting a blunting of training adaptations with supplementation. The up-regulation of endogenous antioxidant systems brought about by exercise training allows for greater tolerance to subsequent ROS, thus, athletes may benefit from increasing these systems through dietary thiol donors. Recent work has shown supplementation with a cysteine donor (N-acetylcysteine; NAC) improves antioxidant capacity by augmenting glutathione levels and reducing markers of oxidative stress, as well as ergogenic potential through association with delayed fatigue in numerous experimental models. However, the use of this, and other thiol donors may have adverse physiological effects. A recent discovery for the use of a thiol donor food source, keratin, to potentially enhance endogenous antioxidants may have important implications for endurance athletes hoping to enhance performance and recovery without blunting training adaptations.

Combining motivational and volitional interventions to promote exercise participation: protection motivation theory and implementation intentions.

PubMed

Milne, Sarah; Orbell, Sheina; Sheeran, Paschal

2002-05-01

This study compared a motivational intervention based on protection motivation theory (PMT, Rogers, 1975, 1983) with the same motivational intervention augmented by a volitional intervention based on implementation intentions (Gollwitzer, 1993). The study had a longitudinal design, involving three waves of data collection over a 2-week period, incorporating an experimental manipulation of PMT variables at Time 1 and a volitional, implementation intention intervention at Time 2. Participants (N=248) were randomly allocated to a control group or one of two intervention groups. Cognitions and exercise behaviour were measured at three time-points over a 2-week period. The motivational intervention significantly increased threat and coping appraisal and intentions to engage in exercise but did not bring about a significant increase in subsequent exercise behaviour. In contrast, the combined protection motivation theory/implementation intention intervention had a dramatic effect on subsequent exercise behaviour. This volitional intervention did not influence behavioural intention or any other motivational variables. It is concluded that supplementing PMT with implementation intentions strengthens the ability of the model to explain behaviour. This has implications for health education programmes, which should aim to increase both participants' motivation and their volition.

An augmented reality system for upper-limb post-stroke motor rehabilitation: a feasibility study.

PubMed

Assis, Gilda Aparecida de; Corrêa, Ana Grasielle Dionísio; Martins, Maria Bernardete Rodrigues; Pedrozo, Wendel Goes; Lopes, Roseli de Deus

2016-08-01

To determine the clinical feasibility of a system based on augmented reality for upper-limb (UL) motor rehabilitation of stroke participants. A physiotherapist instructed the participants to accomplish tasks in augmented reality environment, where they could see themselves and their surroundings, as in a mirror. Two case studies were conducted. Participants were evaluated pre- and post-intervention. The first study evaluated the UL motor function using Fugl-Meyer scale. Data were compared using non-parametric sign tests and effect size. The second study used the gain of motion range of shoulder flexion and abduction assessed by computerized biophotogrammetry. At a significance level of 5%, Fugl-Meyer scores suggested a trend for greater UL motor improvement in the augmented reality group than in the other. Moreover, effect size value 0.86 suggested high practical significance for UL motor rehabilitation using the augmented reality system. System provided promising results for UL motor rehabilitation, since enhancements have been observed in the shoulder range of motion and speed. Implications for Rehabilitation Gain of range of motion of flexion and abduction of the shoulder of post-stroke patients can be achieved through an augmented reality system containing exercises to promote the mental practice. NeuroR system provides a mental practice method combined with visual feedback for motor rehabilitation of chronic stroke patients, giving the illusion of injured upper-limb (UL) movements while the affected UL is resting. Its application is feasible and safe. This system can be used to improve UL rehabilitation, an additional treatment past the traditional period of the stroke patient hospitalization and rehabilitation.

When pliers become fingers in the monkey motor system

PubMed Central

Umiltà, M. A.; Escola, L.; Intskirveli, I.; Grammont, F.; Rochat, M.; Caruana, F.; Jezzini, A.; Gallese, V.; Rizzolatti, G.

2008-01-01

The capacity to use tools is a fundamental evolutionary achievement. Its essence stands in the capacity to transfer a proximal goal (grasp a tool) to a distal goal (e.g., grasp food). Where and how does this goal transfer occur? Here, we show that, in monkeys trained to use tools, cortical motor neurons, active during hand grasping, also become active during grasping with pliers, as if the pliers were now the hand fingers. This motor embodiment occurs both for normal pliers and for “reverse pliers,” an implement that requires finger opening, instead of their closing, to grasp an object. We conclude that the capacity to use tools is based on an inherently goal-centered functional organization of primate cortical motor areas. PMID:18238904

The contributions of vision and haptics to reaching and grasping

PubMed Central

Stone, Kayla D.; Gonzalez, Claudia L. R.

2015-01-01

This review aims to provide a comprehensive outlook on the sensory (visual and haptic) contributions to reaching and grasping. The focus is on studies in developing children, normal, and neuropsychological populations, and in sensory-deprived individuals. Studies have suggested a right-hand/left-hemisphere specialization for visually guided grasping and a left-hand/right-hemisphere specialization for haptically guided object recognition. This poses the interesting possibility that when vision is not available and grasping relies heavily on the haptic system, there is an advantage to use the left hand. We review the evidence for this possibility and dissect the unique contributions of the visual and haptic systems to grasping. We ultimately discuss how the integration of these two sensory modalities shape hand preference. PMID:26441777

Grasping isoluminant stimuli.

PubMed

Kleinholdermann, Urs; Franz, Volker H; Gegenfurtner, Karl R; Stockmeier, Kerstin

2009-07-01

We used a virtual reality setup to let participants grasp discs, which differed in luminance, chromaticity and size. Current theories on perception and action propose a division of labor in the brain into a color proficient perception pathway and a less color-capable action pathway. In this study, we addressed the question whether isoluminant stimuli, which provide only a chromatic but no luminance contrast for action planning, are harder to grasp than stimuli providing luminance contrast or both kinds of contrast. Although we found that grasps of isoluminant stimuli had a slightly steeper slope relating the maximum grip aperture to disc size, all other measures of grip quality were unaffected. Overall, our results do not support the view that isoluminance of stimulus and background impedes the planning of a grasping movement.

Extending the Cortical Grasping Network: Pre-supplementary Motor Neuron Activity During Vision and Grasping of Objects

PubMed Central

Lanzilotto, Marco; Livi, Alessandro; Maranesi, Monica; Gerbella, Marzio; Barz, Falk; Ruther, Patrick; Fogassi, Leonardo; Rizzolatti, Giacomo; Bonini, Luca

2016-01-01

Grasping relies on a network of parieto-frontal areas lying on the dorsolateral and dorsomedial parts of the hemispheres. However, the initiation and sequencing of voluntary actions also requires the contribution of mesial premotor regions, particularly the pre-supplementary motor area F6. We recorded 233 F6 neurons from 2 monkeys with chronic linear multishank neural probes during reaching–grasping visuomotor tasks. We showed that F6 neurons play a role in the control of forelimb movements and some of them (26%) exhibit visual and/or motor specificity for the target object. Interestingly, area F6 neurons form 2 functionally distinct populations, showing either visually-triggered or movement-related bursts of activity, in contrast to the sustained visual-to-motor activity displayed by ventral premotor area F5 neurons recorded in the same animals and with the same task during previous studies. These findings suggest that F6 plays a role in object grasping and extend existing models of the cortical grasping network. PMID:27733538

Dynamical characteristics of surface EMG signals of hand grasps via recurrence plot.

PubMed

Ouyang, Gaoxiang; Zhu, Xiangyang; Ju, Zhaojie; Liu, Honghai

2014-01-01

Recognizing human hand grasp movements through surface electromyogram (sEMG) is a challenging task. In this paper, we investigated nonlinear measures based on recurrence plot, as a tool to evaluate the hidden dynamical characteristics of sEMG during four different hand movements. A series of experimental tests in this study show that the dynamical characteristics of sEMG data with recurrence quantification analysis (RQA) can distinguish different hand grasp movements. Meanwhile, adaptive neuro-fuzzy inference system (ANFIS) is applied to evaluate the performance of the aforementioned measures to identify the grasp movements. The experimental results show that the recognition rate (99.1%) based on the combination of linear and nonlinear measures is much higher than those with only linear measures (93.4%) or nonlinear measures (88.1%). These results suggest that the RQA measures might be a potential tool to reveal the sEMG hidden characteristics of hand grasp movements and an effective supplement for the traditional linear grasp recognition methods.

Grip type and task goal modify reach-to-grasp performance in post-stroke hemiparesis.

PubMed

Schaefer, Sydney Y; DeJong, Stacey L; Cherry, Kendra M; Lang, Catherine E

2012-04-01

This study investigated whether grip type and/or task goal influenced reaching and grasping performance in poststroke hemiparesis. Sixteen adults with poststroke hemiparesis and twelve healthy adults reached to and grasped a cylindrical object using one of two grip types (3-finger or palmar) to achieve one of two task goals (hold or lift). Performance of the stroke group was characteristic of hemiparetic limb movement during reach-to-grasp, with more curved handpaths and slower velocities compared with the control group. These effects were present regardless of grip type or task goal. Other measures of reaching (reach time and reach velocity at object contact) and grasping (peak thumb-index finger aperture during the reach and peak grip force during the grasp) were differentially affected by grip type, task goal, or both, despite the presence of hemiparesis, providing new evidence that changes in motor patterns after stroke may occur to compensate for stroke-related motor impairment.

A simple rule of thumb for elegant prehension.

PubMed

Mon-Williams, M; Tresilian, J R

2001-07-10

Reaching out to grasp an object (prehension) is a deceptively elegant and skilled behavior. The movement prior to object contact can be described as having two components, the movement of the hand to an appropriate location for gripping the object, the "transport" component, and the opening and closing of the aperture between the fingers as they prepare to grip the target, the "grasp" component. The grasp component is sensitive to the size of the object, so that a larger grasp aperture is formed for wider objects; the maximum grasp aperture (MGA) is a little wider than the width of the target object and occurs later in the movement for larger objects. We present a simple model that can account for the temporal relationship between the transport and grasp components. We report the results of an experiment providing empirical support for our "rule of thumb." The model provides a simple, but plausible, account of a neural control strategy that has been the center of debate over the last two decades.

Grip type and task goal modify reach-to-grasp performance in post-stroke hemiparesis

PubMed Central

Schaefer, Sydney Y.; DeJong, Stacey L.; Cherry, Kendra M.; Lang, Catherine E.

2011-01-01

This study investigated whether grip type and/or task goal influenced reaching and grasping performance in post-stroke hemiparesis. Sixteen adults with post-stroke hemiparesis and twelve healthy adults reached to and grasped a cylindrical object using one of two grip types (3-finger or palmar) to achieve one of two task goals (hold or lift). Performance of the stroke group was characteristic of hemiparetic limb movement during reach-to-grasp, with more curved handpaths and slower velocities compared to the control group. These effects were present regardless of grip type or task goal. Other measures of reaching (reach time and reach velocity at object contact) and grasping (peak thumb-index finger aperture during the reach and peak grip force during the grasp) were differentially affected by grip type, task goal, or both, despite the presence of hemiparesis, providing new evidence that changes in motor patterns after stroke may occur to compensate for stroke-related motor impairment. PMID:22357103

Explicit knowledge about the availability of visual feedback affects grasping with the left but not the right hand.

PubMed

Tang, Rixin; Whitwell, Robert L; Goodale, Melvyn A

2014-01-01

Previous research (Whitwell et al. in Exp Brain Res 188:603-611, 2008; Whitwell and Goodale in Exp Brain Res 194:619-629, 2009) has shown that trial history, but not anticipatory knowledge about the presence or absence of visual feedback on an upcoming trial, plays a vital role in determining how that feedback is exploited when grasping with the right hand. Nothing is known about how the non-dominant left hand behaves under the same feedback regimens. In present study, therefore, we compared peak grip aperture (PGA) for left- and right-hand grasps executed with and without visual feedback (i.e., closed- vs. open-loop conditions) in right-handed individuals under three different trial schedules: the feedback conditions were blocked separately, they were randomly interleaved, or they were alternated. When feedback conditions were blocked, the PGA was much larger for open-loop trials as compared to closed-loop trials, although this difference was more pronounced for right-hand grasps than left-hand grasps. Like Whitwell et al., we found that mixing open- and closed-loop trials together, compared to blocking them separately, homogenized the PGA for open- and closed-loop grasping in the right hand (i.e., the PGAs became smaller on open-loop trials and larger on closed-loop trials). In addition, the PGAs for right-hand grasps were entirely determined by trial history and not by knowledge of whether or not visual feedback would be available on an upcoming trial. In contrast to grasps made with the right hand, grasps made by the left hand were affected both by trial history and by anticipatory knowledge of the upcoming visual feedback condition. But these effects were observed only on closed-loop trials, i.e., the PGAs of grasps made with the left hand on closed-loop trials were smaller when participants could anticipate the availability of feedback on an upcoming trial (alternating trials) than when they could not (randomized trials). In contrast, grasps made with the left hand on open-loop trials exhibited the same large PGAs under all feedback schedules: blocked, random, or alternating. In other words, there was no evidence for homogenization. Taken together, these results suggest that in addition to the real-time demands of the task, such as the target's size and position and the availability of visual feedback, the initial (i.e., pre-movement) programming of right-hand grasping relies on what happened on the previous trial, whereas the programming of left-hand grasping is more cognitively supervised and exploits explicit information about trial order to prepare for an upcoming trial.

High-Intensity Interval Cycling Exercise on Wave Reflection and Pulse Wave Velocity.

PubMed

Kingsley, J Derek; Tai, Yu Lun; Vaughan, Jeremiah A; Mayo, Xián

2017-05-01

Kingsley, JD, Tai, YL, Vaughan, J, and Mayo, X. High-intensity interval cycling exercise on wave reflection and pulse wave velocity. J Strength Cond Res 31(5): 1313-1320, 2017-The purpose of this study was to assess the effects of high-intensity exercise on wave reflection and aortic stiffness. Nine young, healthy men (mean ± SD: age: 22 ± 2 years) participated in the study. The high-intensity interval cycling exercise consisted of 3 sets of Wingate Anaerobic Tests (WATs) with 7.5% of bodyweight as resistance and 2 minutes of rest between each set. Measurements were taken at rest and 1 minute after completion of the WATs. Brachial and aortic blood pressures, as well as wave reflection characteristics, were measured through pulse wave analysis. Aortic stiffness was assessed through carotid-femoral pulse wave velocity (cfPWV). A repeated-measures analysis of variance was used to investigate the effects of the WATs on blood pressure and vascular function across time. There was no change in brachial or aortic systolic pressure from rest to recovery. There was a significant (p ≤ 0.05) decrease in brachial diastolic pressure (rest: 73 ± 6 mm Hg; recovery: 67 ± 9 mm Hg) and aortic diastolic pressure (rest: 75 ± 6 mm Hg; recovery: 70 ± 9 mm Hg) from rest to recovery. In addition, there was no significant change in the augmentation index (rest: 111.4 ± 6.5%; recovery: 109.8 ± 5.8%, p = 0.65) from rest to recovery. However, there was a significant (p ≤ 0.05) increase in the augmentation index normalized at 75 b·min (rest: 3.29 ± 9.82; recovery 21.21 ± 10.87) during recovery compared with rest. There was no change in cfPWV (rest: 5.3 ± 0.8 m·s; recovery: 5.7 ± 0.5m·s; p = 0.09) in response to the WAT. These data demonstrate that high-intensity interval cycling exercise with short rest periods has a nonsignificant effect on vascular function.

Differences in postprandial protein handling after beef compared with milk ingestion during postexercise recovery: a randomized controlled trial.

PubMed

Burd, Nicholas A; Gorissen, Stefan H; van Vliet, Stephan; Snijders, Tim; van Loon, Luc Jc

2015-10-01

Protein consumed after resistance exercise increases postexercise muscle protein synthesis rates. To date, dairy protein has been studied extensively, with little known about the capacity of other protein-dense foods to augment postexercise muscle protein synthesis rates. We aimed to compare protein digestion and absorption kinetics, postprandial amino acid availability, anabolic signaling, and the subsequent myofibrillar protein synthetic response after the ingestion of milk compared with beef during recovery from resistance-type exercise. In crossover trials, 12 healthy young men performed a single bout of resistance exercise. Immediately after cessation of exercise, participants ingested 30 g protein by consuming isonitrogenous amounts of intrinsically l-[1-(13)C]phenylalanine-labeled beef or milk. Blood and muscle biopsy samples were collected at rest and after exercise during primed continuous infusions of l-[ring-(2)H5]phenylalanine and l-[ring-3,5-(2)H2]tyrosine to assess protein digestion and absorption kinetics, plasma amino acid availability, anabolic signaling, and subsequent myofibrillar protein synthesis rates in vivo in young men. Beef protein-derived phenylalanine appeared more rapidly in circulation compared with milk ingestion (P < 0.001). The availability of phenylalanine during the 5-h postexercise period tended to be higher after beef (64% ± 3%) ingestion than after milk ingestion (57% ± 3%; P = 0.08). Both beef and milk ingestion were followed by an increase in the phosphorylation of mammalian target of rapamycin complex 1 and 70-kDa S6 protein kinase 1 during postexercise recovery. Milk ingestion increased myofibrillar protein synthesis rates to a greater extent than did beef ingestion during the 0- to 2-h postexercise phase (P = 0.013). However, the increase in myofibrillar protein synthesis rates did not differ between milk and beef ingestion during the entire 0- to 5-h postexercise phase (P = 0.114). Both milk and beef ingestion augment the postexercise myofibrillar protein synthetic response in young men, with a stronger stimulation of myofibrillar protein synthesis during the early postprandial stage after milk ingestion. This trial was registered at www.clinicaltrials.gov as NCT01578590. © 2015 American Society for Nutrition.

Endurance, interval sprint, and resistance exercise training: impact on microvascular dysfunction in type 2 diabetes

PubMed Central

Laughlin, M. Harold

2015-01-01

Type 2 diabetes (T2D) alters capillary hemodynamics, causes capillary rarefaction in skeletal muscle, and alters endothelial and vascular smooth muscle cell phenotype, resulting in impaired vasodilatory responses. These changes contribute to altered blood flow responses to physiological stimuli, such as exercise and insulin secretion. T2D-induced microvascular dysfunction impairs glucose and insulin delivery to skeletal muscle (and other tissues such as skin and nervous), thereby reducing glucose uptake and perpetuating hyperglycemia and hyperinsulinemia. In patients with T2D, exercise training (EX) improves microvascular vasodilator and insulin signaling and attenuates capillary rarefaction in skeletal muscle. EX-induced changes subsequently augment glucose and insulin delivery as well as glucose uptake. If these adaptions occur in a sufficient amount of tissue, and skeletal muscle in particular, chronic exposure to hyperglycemia and hyperinsulinemia and the risk of microvascular complications in all vascular beds will decrease. We postulate that EX programs that engage as much skeletal muscle mass as possible and recruit as many muscle fibers within each muscle as possible will generate the greatest improvements in microvascular function, providing that the duration of the stimulus is sufficient. Primary improvements in microvascular function occur in tissues (skeletal muscle primarily) engaged during exercise, and secondary improvements in microvascular function throughout the body may result from improved blood glucose control. We propose that the added benefit of combined resistance and aerobic EX programs and of vigorous intensity EX programs is not simply “more is better.” Rather, we believe the additional benefit is the result of EX-induced adaptations in and around more muscle fibers, resulting in more muscle mass and the associated microvasculature being changed. Thus, to acquire primary and secondary improvements in microvascular function and improved blood glucose control, EX programs should involve upper and lower body exercise and modulate intensity to augment skeletal muscle fiber recruitment. Under conditions of limited mobility, it may be necessary to train skeletal muscle groups separately to maximize whole body skeletal muscle fiber recruitment. PMID:26408541

Measurement and Data Transmission Validity of a Multi-Biosensor System for Real-Time Remote Exercise Monitoring Among Cardiac Patients.

PubMed

Rawstorn, Jonathan C; Gant, Nicholas; Warren, Ian; Doughty, Robert Neil; Lever, Nigel; Poppe, Katrina K; Maddison, Ralph

2015-03-20

Remote telemonitoring holds great potential to augment management of patients with coronary heart disease (CHD) and atrial fibrillation (AF) by enabling regular physiological monitoring during physical activity. Remote physiological monitoring may improve home and community exercise-based cardiac rehabilitation (exCR) programs and could improve assessment of the impact and management of pharmacological interventions for heart rate control in individuals with AF. Our aim was to evaluate the measurement validity and data transmission reliability of a remote telemonitoring system comprising a wireless multi-parameter physiological sensor, custom mobile app, and middleware platform, among individuals in sinus rhythm and AF. Participants in sinus rhythm and with AF undertook simulated daily activities, low, moderate, and/or high intensity exercise. Remote monitoring system heart rate and respiratory rate were compared to reference measures (12-lead ECG and indirect calorimeter). Wireless data transmission loss was calculated between the sensor, mobile app, and remote Internet server. Median heart rate (-0.30 to 1.10 b∙min -1 ) and respiratory rate (-1.25 to 0.39 br∙min -1 ) measurement biases were small, yet statistically significant (all P≤.003) due to the large number of observations. Measurement reliability was generally excellent (rho=.87-.97, all P<.001; intraclass correlation coefficient [ICC]=.94-.98, all P<.001; coefficient of variation [CV]=2.24-7.94%), although respiratory rate measurement reliability was poor among AF participants (rho=.43, P<.001; ICC=.55, P<.001; CV=16.61%). Data loss was minimal (<5%) when all system components were active; however, instability of the network hosting the remote data capture server resulted in data loss at the remote Internet server during some trials. System validity was sufficient for remote monitoring of heart and respiratory rates across a range of exercise intensities. Remote exercise monitoring has potential to augment current exCR and heart rate control management approaches by enabling the provision of individually tailored care to individuals outside traditional clinical environments. ©Jonathan C Rawstorn, Nicholas Gant, Ian Warren, Robert Neil Doughty, Nigel Lever, Katrina K Poppe, Ralph Maddison. Originally published in JMIR Rehabilitation and Assistive Technology (http://rehab.jmir.org), 20.03.2015.

Coronary Exercise Hyperemia Is Impaired in Patients with Peripheral Arterial Disease.

PubMed

Ross, Amanda J; Gao, Zhaohui; Luck, Jonathan Carter; Blaha, Cheryl A; Cauffman, Aimee E; Aziz, Faisal; Radtka, John F; Proctor, David N; Leuenberger, Urs A; Sinoway, Lawrence I; Muller, Matthew D

2017-01-01

Peripheral arterial disease (PAD) is an atherosclerotic vascular disease that affects over 200 million people worldwide. The hallmark of PAD is ischemic leg pain and this condition is also associated with an augmented blood pressure response to exercise, impaired vascular function, and high risk of myocardial infarction and cardiovascular mortality. In this study, we tested the hypothesis that coronary exercise hyperemia is impaired in PAD. Twelve patients with PAD and no overt coronary disease (65 ± 2 years, 7 men) and 15 healthy control subjects (64 ± 2 years, 9 men) performed supine plantar flexion exercise (30 contractions/min, increasing workload). A subset of subjects (n = 7 PAD, n = 8 healthy) also performed isometric handgrip exercise (40% of maximum voluntary contraction to fatigue). Coronary blood velocity in the left anterior descending artery was measured by transthoracic Doppler echocardiography; blood pressure and heart rate were monitored continuously. Coronary blood velocity responses to 4 min of plantar flexion exercise (PAD: Δ2.4 ± 1.2, healthy: Δ6.0 ± 1.6 cm/sec, P = 0.039) and isometric handgrip exercise (PAD: Δ8.3 ± 4.2, healthy: Δ16.9 ± 3.6, P = 0.033) were attenuated in PAD patients. These data indicate that coronary exercise hyperemia is impaired in PAD, which may predispose these patients to myocardial ischemia. Copyright © 2016 Elsevier Inc. All rights reserved.

Dynamic and Static Exercises Differentially Affect Plasma Cytokine Content in Elite Endurance- and Strength-Trained Athletes and Untrained Volunteers

PubMed Central

Kapilevich, Leonid V.; Zakharova, Anna N.; Kabachkova, Anastasia V.; Kironenko, Tatyana A.; Orlov, Sergei N.

2017-01-01

Extensive exercise increases the plasma content of IL-6, IL-8, IL-15, leukemia inhibitory factor (LIF), and several other cytokines via their augmented transcription in skeletal muscle cells. However, the relative impact of aerobic and resistant training interventions on cytokine production remains poorly defined. In this study, we compared effects of dynamic and static load on cytokine plasma content in elite strength- and endurance-trained athletes vs. healthy untrained volunteers. The plasma cytokine content was measured before, immediately after, and 30 min post-exercise using enzyme-linked immunosorbent assay. Pedaling on a bicycle ergometer increased IL-6 and IL-8 content in the plasma of trained athletes by about 4- and 2-fold, respectively. In contrast to dynamic load, weightlifting had negligible impact on these parameters in strength exercise-trained athletes. Unlike IL-6 and IL-8, dynamic exercise had no impact on IL-15 and LIF, whereas static load increases the content of these cytokines by ~50%. Two-fold increment of IL-8 content seen in athletes subjected to dynamic exercise was absent in untrained individuals, whereas the ~50% increase in IL-15 triggered by static load in the plasma of weightlifting athletes was not registered in the control group. Thus, our results show the distinct impact of static and dynamic exercises on cytokine content in the plasma of trained athletes. They also demonstrate that both types of exercises differentially affect cytokine content in plasma of athletes and untrained persons. PMID:28194116

Biclustering of gene expression data using reactive greedy randomized adaptive search procedure.

PubMed

Dharan, Smitha; Nair, Achuthsankar S

2009-01-30

Biclustering algorithms belong to a distinct class of clustering algorithms that perform simultaneous clustering of both rows and columns of the gene expression matrix and can be a very useful analysis tool when some genes have multiple functions and experimental conditions are diverse. Cheng and Church have introduced a measure called mean squared residue score to evaluate the quality of a bicluster and has become one of the most popular measures to search for biclusters. In this paper, we review basic concepts of the metaheuristics Greedy Randomized Adaptive Search Procedure (GRASP)-construction and local search phases and propose a new method which is a variant of GRASP called Reactive Greedy Randomized Adaptive Search Procedure (Reactive GRASP) to detect significant biclusters from large microarray datasets. The method has two major steps. First, high quality bicluster seeds are generated by means of k-means clustering. In the second step, these seeds are grown using the Reactive GRASP, in which the basic parameter that defines the restrictiveness of the candidate list is self-adjusted, depending on the quality of the solutions found previously. We performed statistical and biological validations of the biclusters obtained and evaluated the method against the results of basic GRASP and as well as with the classic work of Cheng and Church. The experimental results indicate that the Reactive GRASP approach outperforms the basic GRASP algorithm and Cheng and Church approach. The Reactive GRASP approach for the detection of significant biclusters is robust and does not require calibration efforts.

From reaching to reach-to-grasp: the arm posture difference and its implications on human motion control strategy.

PubMed

Li, Zhi; Milutinović, Dejan; Rosen, Jacob

2017-05-01

Reach-to-grasp arm postures differ from those in pure reaching because they are affected by grasp position/orientation, rather than simple transport to a position during a reaching motion. This paper investigates this difference via an analysis of experimental  data collected on reaching and reach-to-grasp motions. A seven-degree-of-freedom (DOFs) kinematic arm model with the swivel angle is used for the motion analysis. Compared to a widely used anatomical arm model, this model distinguishes clearly the four grasping-relevant DOFs (GR-DOFs) that are affected by positions and orientations of the objects to be grasped. These four GR-DOFs include the swivel angle that measures the elbow rotation about the shoulder-wrist axis, and three wrist joint angles. For each GR-DOF, we quantify position vs orientation task-relevance bias that measures how much the DOF is affected by the grasping position vs orientation. The swivel angle and forearm supination have similar bias, and the analysis of their motion suggests two hypotheses regarding the synergistic coordination of the macro- and micro-structures of the human arm (1) DOFs with similar task-relevance are synergistically coordinated; and (2) such synergy breaks when a task-relevant DOF is close to its joint limit without necessarily reaching the limit. This study provides a motion analysis method to reduce the control complexity for reach-to-grasp tasks, and suggests using dynamic coupling to coordinate the hand and arm of upper-limb exoskeletons.

General Rotorcraft Aeromechanical Stability Program (GRASP): Theory manual

NASA Technical Reports Server (NTRS)

Hodges, Dewey H.; Hopkins, A. Stewart; Kunz, Donald L.; Hinnant, Howard E.

1990-01-01

The general rotorcraft aeromechanical stability program (GRASP) was developed to calculate aeroelastic stability for rotorcraft in hovering flight, vertical flight, and ground contact conditions. GRASP is described in terms of its capabilities and its philosophy of modeling. The equations of motion that govern the physical system are described, as well as the analytical approximations used to derive them. The equations include the kinematical equation, the element equations, and the constraint equations. In addition, the solution procedures used by GRASP are described. GRASP is capable of treating the nonlinear static and linearized dynamic behavior of structures represented by arbitrary collections of rigid-body and beam elements. These elements may be connected in an arbitrary fashion, and are permitted to have large relative motions. The main limitation of this analysis is that periodic coefficient effects are not treated, restricting rotorcraft flight conditions to hover, axial flight, and ground contact. Instead of following the methods employed in other rotorcraft programs. GRASP is designed to be a hybrid of the finite-element method and the multibody methods used in spacecraft analysis. GRASP differs from traditional finite-element programs by allowing multiple levels of substructure in which the substructures can move and/or rotate relative to others with no small-angle approximations. This capability facilitates the modeling of rotorcraft structures, including the rotating/nonrotating interface and the details of the blade/root kinematics for various types. GRASP differs from traditional multibody programs by considering aeroelastic effects, including inflow dynamics (simple unsteady aerodynamics) and nonlinear aerodynamic coefficients.

Bed rest attenuates sympathetic and pressor responses to isometric exercise in antigravity leg muscles in humans.

PubMed

Kamiya, Atsunori; Michikami, Daisaku; Shiozawa, Tomoki; Iwase, Satoshi; Hayano, Junichiro; Kawada, Toru; Sunagawa, Kenji; Mano, Tadaaki

2004-05-01

Although spaceflight and bed rest are known to cause muscular atrophy in the antigravity muscles of the legs, the changes in sympathetic and cardiovascular responses to exercises using the atrophied muscles remain unknown. We hypothesized that bed rest would augment sympathetic responses to isometric exercise using antigravity leg muscles in humans. Ten healthy male volunteers were subjected to 14-day 6 degrees head-down bed rest. Before and after bed rest, they performed isometric exercises using leg (plantar flexion) and forearm (handgrip) muscles, followed by 2-min postexercise muscle ischemia (PEMI) that continues to stimulate the muscle metaboreflex. These exercises were sustained to fatigue. We measured muscle sympathetic nerve activity (MSNA) in the contralateral resting leg by microneurography. In both pre- and post-bed-rest exercise tests, exercise intensities were set at 30 and 70% of the maximum voluntary force measured before bed rest. Bed rest attenuated the increase in MSNA in response to fatiguing plantar flexion by approximately 70% at both exercise intensities (both P < 0.05 vs. before bed rest) and reduced the maximal voluntary force of plantar flexion by 15%. In contrast, bed rest did not alter the increase in MSNA response to fatiguing handgrip and had no effects on the maximal voluntary force of handgrip. Although PEMI sustained MSNA activation before bed rest in all trials, bed rest entirely eliminated the PEMI-induced increase in MSNA in leg exercises but partially attenuated it in forearm exercises. These results do not support our hypothesis but indicate that bed rest causes a reduction in isometric exercise-induced sympathetic activation in (probably atrophied) antigravity leg muscles.

Cyclical blood flow restriction resistance exercise: a potential parallel to remote ischemic preconditioning?

PubMed

Sprick, Justin D; Rickards, Caroline A

2017-11-01

Remote ischemic preconditioning (RIPC) is characterized by the cyclical application of limb blood flow restriction and reperfusion and has been shown to protect vital organs during a subsequent ischemic insult. Blood flow restriction exercise (BFRE) similarly combines bouts of blood flow restriction with low-intensity exercise and thus could potentially emulate the protection demonstrated by RIPC. One concern with BFRE, however, is the potential for an augmented rise in sympathetic outflow due to greater activation of the exercise pressor reflex. Because of the use of lower workloads, however, we hypothesized that BFRE would elicit an attenuated increase in sympathetic outflow [assessed via plasma norepinephrine (NE) and mean arterial pressure (MAP)] and middle cerebral artery velocity (MCAv) when compared with conventional exercise (CE). Fifteen subjects underwent two leg press exercise interventions: 1 ) BFRE-220 mmHg bilateral thigh occlusion at 20% 1 rep-max (1RM), and 2 ) CE-65% 1RM without occlusion. Each condition consisted of 4 × 5-min cycles of exercise, with 3 × 10-reps in each cycle. Five minutes of rest and reperfusion (for BFRE) followed each cycle. MAP increased with exercise ( P < 0.001) and was 4-5 mmHg higher with CE versus BFRE ( P ≤ 0.09). Mean MCAv also increased with exercise ( P < 0.001) and was higher with CE compared with BFRE during the first bout of exercise only ( P = 0.07). Plasma NE concentration increased with CE only ( P < 0.001) and was higher than BFRE throughout exercise ( P ≤ 0.02). The attenuated sympathetic response, combined with similar cerebrovascular responses, suggest that cyclical BFRE could be explored as an alternative to CE in the clinical setting. Copyright © 2017 the American Physiological Society.

Regulation of coronary resistance vessel tone in response to exercise.

PubMed

Duncker, Dirk J; Bache, Robert J; Merkus, Daphne

2012-04-01

Exercise is a primary stimulus for increased myocardial oxygen demand. The ~6-fold increase in oxygen demand of the left ventricle during heavy exercise is met principally by augmenting coronary blood flow (~5-fold), as hemoglobin concentration and oxygen extraction (which is already ~70% at rest) increase only modestly in most species. As a result, coronary blood flow is tightly coupled to myocardial oxygen consumption over a wide range of physical activity. This tight coupling has been proposed to depend on periarteriolar oxygen tension, signals released from cardiomyocytes and the endothelium as well as neurohumoral influences, but the contribution of each of these regulatory pathways, and their interactions, to exercise hyperemia in the heart remain incompletely understood. In humans, nitric oxide, adenosine and K(ATP) channels each appear to contribute to resting coronary resistance vessel tone, but evidence for a critical contribution to exercise hyperemia is lacking. In dogs K(ATP)-channel activation together with adenosine and nitric oxide contribute to exercise hyperemia in a non-linear redundant fashion. In contrast, in swine nitric oxide, adenosine and K(ATP) channels contribute to resting coronary resistance vessel tone control in a linear additive manner, but do not appear to be mandatory for exercise hyperemia. Rather, exercise hyperemia in swine appears to involve β-adrenergic activation in conjunction with exercise-induced blunting of an endothelin-mediated vasoconstrictor influence. In view of these remarkable species differences in coronary vasomotor control during exercise, future studies are required to determine the system of vasodilator components that mediate exercise hyperemia in humans. This article is part of a Special Issue entitled "Coronary Blood Flow". Copyright © 2011 Elsevier Ltd. All rights reserved.

One year of high-intensity interval training improves exercise capacity, but not left ventricular function in stable heart transplant recipients: a randomised controlled trial.

PubMed

Rustad, Lene A; Nytrøen, Kari; Amundsen, Brage H; Gullestad, Lars; Aakhus, Svend

2014-02-01

Heart transplant recipients have lower exercise capacity and impaired cardiac function compared with the normal population. High-intensity interval training (HIIT) improves exercise capacity and cardiac function in patients with heart failure and hypertension, but the effect on cardiac function in stable heart transplant recipients is not known. Thus, we investigated whether HIIT improved cardiac function and exercise capacity in stable heart transplant recipients by use of comprehensive rest- and exercise-echocardiography and cardiopulmonary exercise testing. Fifty-two clinically stable heart transplant recipients were randomised either to HIIT (4 × 4 minutes at 85-95% of peak heart rate three times per week for eight weeks) or to control. Three such eight-week periods were distributed throughout one year. Echocardiography (rest and submaximal exercise) and cardiopulmonary exercise testing were performed at baseline and follow-up. One year of HIIT increased VO 2peak from 27.7 ± 5.5 at baseline to 30.9 ± 5.0 ml/kg/min at follow-up, while the control group remained unchanged (28.5 ± 7.0 vs. 28.0 ± 6.7 ml/kg per min, p < 0.001 for difference between the groups). Systolic and diastolic left ventricular functions at rest and during exercise were generally unchanged by HIIT. Whereas HIIT is feasible in heart transplant recipients and effectively improves exercise capacity, it does not alter cardiac systolic and diastolic function significantly. Thus, the observed augmentation in exercise capacity is best explained by extra-cardiac adaptive mechanisms.

Acute resistance exercise using free weights on aortic wave reflection characteristics.

PubMed

Tai, Yu Lun; Gerhart, Hayden; Mayo, Xián; Kingsley, J Derek

2018-01-01

Aortic wave reflection characteristics such as the augmentation index (AIx), wasted left ventricular pressure energy (ΔE w ) and aortic haemodynamics, such as aortic systolic blood pressure (ASBP), strongly predict cardiovascular events. The effects of acute resistance exercise (ARE) using free-weight exercises on these characteristics are unknown. Therefore, we sought to determine the effects of acute free-weight resistance exercise on aortic wave reflection characteristics and aortic haemodynamics in resistance-trained individuals. Fifteen young, healthy resistance-trained (9 ± 3 years) individuals performed two randomized sessions consisting of an acute bout of free-weight resistance exercise (ARE) or a quiet control (CON). The ARE consisted of three sets of 10 repetitions at 75% one repetition maximum for squat, bench press and deadlift. In CON, the participants rested in the supine position for 30 min. Measurements were made at baseline before sessions and 10 min after sessions. A two-way ANOVA was used to compare the effects of condition across time. There were no significant interactions for aortic or brachial blood pressures. Compared to rest, there were significant increases in augmentation pressure (rest: 5·7 ± 3·0 mmHg; recovery: 10·4 ± 5·7 mmHg, P = 0·002), AIx (rest: 116·8 ± 4·2%; recovery: 123·2 ± 8·4%, P = 0·002), AIx normalized at 75 bpm (rest: 5·2 ± 7·6%; recovery: 27·3 ± 13·2%, P<0·0001), ΔE w (rest: 1215 ± 674 dynes s cm -2 ; recovery: 2096 ± 1182 dynes s cm -2 , P = 0·008), and there was a significant decrease in transit time of the reflected wave (rest: 150·7 ± 5·8 ms; recovery 145·5 ± 5·6 ms, P<0·001) during recovery from ARE compared to CON. These data suggest that ARE using free-weight exercises may have no effect on aortic and brachial blood pressure but may significantly alter aortic wave reflection characteristics. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Diet and exercise training reduce blood pressure and improve autonomic modulation in women with prehypertension.

PubMed

Sales, Allan R K; Silva, Bruno M; Neves, Fabricia J; Rocha, Natália G; Medeiros, Renata F; Castro, Renata R T; Nóbrega, Antonio C L

2012-09-01

Despite mortality from heart disease has been decreasing, the decline in death in women remains lower than in men. Hypertension (HT) is a major risk factor for cardiovascular disease. Therefore, approaches to prevent or delay the onset of HT would be valuable in women. Given this background, we investigated the effect of diet and exercise training on blood pressure (BP) and autonomic modulation in women with prehypertension (PHT). Ten women with PHT (39 ± 6 years, mean ± standard deviation) and ten with normotension (NT) (35 ± 11 years) underwent diet and exercise training for 12 weeks. Autonomic modulation was assessed through heart rate (HR) and systolic BP (SBP) variability, using time and frequency domain analyses. At preintervention, women with PHT had higher SBP (PHT: 128 ± 7 vs. NT: 111 ± 6 mmHg, p < 0.05) and lower HR variability [standard deviation of normal-to-normal beats (SDNN), PHT: 41 ± 18 vs. NT: 60 ± 19 ms, p < 0.05]. At post-intervention, peak oxygen consumption and muscular strength increased (p < 0.05), while body mass index decreased in both groups (p < 0.05). However, SBP decreased (118 ± 8 mmHg, p < 0.05 vs. preintervention) and total HR variability tended to increase (total power: 1,397 ± 570 vs. 2,137 ± 1,110 ms(2), p = 0.08) only in the group with PHT; consequently, HR variability became similar between groups at post-intervention (p > 0.05). Moreover, reduction in SBP was associated with augmentation in SDNN (r = -0.46, p < 0.05) and reduction in low-frequency power [LF (n.u.); r = 0.46, p < 0.05]. In conclusion, diet and exercise training reduced SBP in women with PHT, and this was associated with augmentation in parasympathetic and probably reduction in sympathetic cardiac modulation.

Grasping objects autonomously in simulated KC-135 zero-g

NASA Technical Reports Server (NTRS)

Norsworthy, Robert S.

1994-01-01

The KC-135 aircraft was chosen for simulated zero gravity testing of the Extravehicular Activity Helper/retriever (EVAHR). A software simulation of the EVAHR hardware, KC-135 flight dynamics, collision detection and grasp inpact dynamics has been developed to integrate and test the EVAHR software prior to flight testing on the KC-135. The EVAHR software will perform target pose estimation, tracking, and motion estimation for rigid, freely rotating, polyhedral objects. Manipulator grasp planning and trajectory control software has also been developed to grasp targets while avoiding collisions.

Visual guidance in control of grasping.

PubMed

Janssen, Peter; Scherberger, Hansjörg

2015-07-08

Humans and other primates possess a unique capacity to grasp and manipulate objects skillfully, a facility pervasive in everyday life that has undoubtedly contributed to the success of our species. When we reach and grasp an object, various cortical areas in the parietal and frontal lobes work together effortlessly to analyze object shape and position, transform this visual information into useful motor commands, and implement these motor representations to preshape the hand before contact with the object is made. In recent years, a growing number of studies have investigated the neural circuits underlying object grasping in both the visual and motor systems of the macaque monkey. The accumulated knowledge not only helps researchers understand how object grasping is implemented in the primate brain but may also contribute to the development of novel neural interfaces and neuroprosthetics.

The force synergy of human digits in static and dynamic cylindrical grasps.

PubMed

Kuo, Li-Chieh; Chen, Shih-Wei; Lin, Chien-Ju; Lin, Wei-Jr; Lin, Sheng-Che; Su, Fong-Chin

2013-01-01

This study explores the force synergy of human digits in both static and dynamic cylindrical grasping conditions. The patterns of digit force distribution, error compensation, and the relationships among digit forces are examined to quantify the synergetic patterns and coordination of multi-finger movements. This study recruited 24 healthy participants to perform cylindrical grasps using a glass simulator under normal grasping and one-finger restricted conditions. Parameters such as the grasping force, patterns of digit force distribution, and the force coefficient of variation are determined. Correlation coefficients and principal component analysis (PCA) are used to estimate the synergy strength under the dynamic grasping condition. Specific distribution patterns of digit forces are identified for various conditions. The compensation of adjacent fingers for the force in the normal direction of an absent finger agrees with the principle of error compensation. For digit forces in anti-gravity directions, the distribution patterns vary significantly by participant. The forces exerted by the thumb are closely related to those exerted by other fingers under all conditions. The index-middle and middle-ring finger pairs demonstrate a significant relationship. The PCA results show that the normal forces of digits are highly coordinated. This study reveals that normal force synergy exists under both static and dynamic cylindrical grasping conditions.

The Force Synergy of Human Digits in Static and Dynamic Cylindrical Grasps

PubMed Central

Kuo, Li-Chieh; Chen, Shih-Wei; Lin, Chien-Ju; Lin, Wei-Jr; Lin, Sheng-Che; Su, Fong-Chin

2013-01-01

This study explores the force synergy of human digits in both static and dynamic cylindrical grasping conditions. The patterns of digit force distribution, error compensation, and the relationships among digit forces are examined to quantify the synergetic patterns and coordination of multi-finger movements. This study recruited 24 healthy participants to perform cylindrical grasps using a glass simulator under normal grasping and one-finger restricted conditions. Parameters such as the grasping force, patterns of digit force distribution, and the force coefficient of variation are determined. Correlation coefficients and principal component analysis (PCA) are used to estimate the synergy strength under the dynamic grasping condition. Specific distribution patterns of digit forces are identified for various conditions. The compensation of adjacent fingers for the force in the normal direction of an absent finger agrees with the principle of error compensation. For digit forces in anti-gravity directions, the distribution patterns vary significantly by participant. The forces exerted by the thumb are closely related to those exerted by other fingers under all conditions. The index-middle and middle-ring finger pairs demonstrate a significant relationship. The PCA results show that the normal forces of digits are highly coordinated. This study reveals that normal force synergy exists under both static and dynamic cylindrical grasping conditions. PMID:23544151

Corrections in Grasp Posture in Response to Modifications of Action Goals

PubMed Central

Hughes, Charmayne M. L.; Seegelke, Christian; Spiegel, Marnie Ann; Oehmichen, Corinna; Hammes, Julia; Schack, Thomas

2012-01-01

There is ample evidence that people plan their movements to ensure comfortable final grasp postures at the end of a movement. The end-state comfort effect has been found to be a robust constraint during unimanual movements, and leads to the inference that goal-postures are represented and planned prior to movement initiation. The purpose of this study was to examine whether individuals make appropriate corrections to ensure comfortable final goal postures when faced with an unexpected change in action goal. Participants reached for a horizontal cylinder and placed the left or right end of the object into the target disk. As soon as the participant began to move, a secondary stimuli was triggered, which indicated whether the intended action goal had changed or not. Confirming previous research, participants selected initial grasp postures that ensured end-state comfort during non-perturbed trials. In addition, participants made appropriate on-line corrections to their reach-to-grasp movements to ensure end-state comfort during perturbed trials. Corrections in grasp posture occurred early or late in the reach-to-grasp phase. The results indicate that individuals plan their movements to afford comfort at the end of the movement, and that grasp posture planning is controlled via both feedforward and feedback mechanisms. PMID:22970119

Evidence for right-hand feeding biases in a left-handed population.

PubMed

Flindall, Jason W; Stone, Kayla D; Gonzalez, Claudia L R

2015-05-01

We have recently shown that actions with similar kinematic requirements, but different end-state goals may be supported by distinct neural networks. Specifically, we demonstrated that when right-handed individuals reach-to-grasp food items with intent to eat, they produce smaller maximum grip apertures (MGAs) than when they grasp the same item with intent to place it in a location near the mouth. This effect was restricted to right-handed movements; left-handed movements showed no difference between tasks. The current study investigates whether (and to which side) the effect may be lateralized in left-handed individuals. Twenty-one self-identified left-handed participants grasped food items of three different sizes while grasp kinematics were captured via an Optotrak Certus motion capture array. A main effect of task was identified wherein the grasp-to-eat action generated significantly smaller MGAs than did the grasp-to-place action. Further analysis revealed that similar to the findings in right-handed individuals, this effect was significant only during right-handed movements. Upon further inspection however, we found individual differences in the magnitude and direction of the observed lateralization. These results underscore the evolutionary significance of the grasp-to-eat movement in producing population-level right-handedness in humans as well as highlighting the heterogeneity of the left-handed population.

Independent digit movements and precision grip patterns in 1-5-month-old human infants: hand-babbling, including vacuous then self-directed hand and digit movements, precedes targeted reaching.

PubMed

Wallace, Patricia S; Whishaw, Ian Q

2003-01-01

Previous work has described human reflexive grasp patterns in early infancy and visually guided reaching and grasping in late infancy. There has been no examination of hand movements in the intervening period. This was the purpose of the present study. We video recorded the spontaneous hand and digit movements made by alert infants over their first 5 months of age. Over this period, spontaneous hand and digit movements developed from fists to almost continuous, vacuous movements and then to self-directed grasping movements. Amongst the many hand and digit movements observed, four grasping patterns emerged during this period: fists, pre-precision grips associated with numerous digit postures, precision grips including the pincer grasp, and self-directed grasps. The finding that a wide range of independent digit movements and grasp patterns are displayed spontaneously by infants within their first 5 months of age is discussed in relation to the development of the motor system, including the suggestion that direct connections of the pyramidal tract are functional relatively early in infancy. It is also suggested that hand babbling, consisting of first vacuous and then self-directed movements, is preparatory to targeted reaching.

Preschool children adapt grasping movements to upcoming object manipulations: Evidence from a dial rotation task.

PubMed

Herbort, Oliver; Büschelberger, Juliane; Janczyk, Markus

2018-03-01

In adults, the motor plans for object-directed grasping movements reflects the anticipated requirements of intended future object manipulations. This prospective mode of planning has been termed second-order planning. Surprisingly, second-order planning is thought to be fully developed only by 10 years of age, when children master seemingly more complex motor skills. In this study, we tested the hypothesis that already 5- and 6-year-old children consistently use second-order planning but that this ability does not become apparent in tasks that are traditionally used to probe it. We asked 5- and 6-year-olds and adults to grasp and rotate a circular dial in a clockwise or counterclockwise direction. Although children's grasp selections were less consistent on an intra- and inter-individual level than adults' grasp selections, all children adjusted their grasps to the upcoming dial rotations. By contrast, in an also administered bar rotation task, only a subset of children adjusted their grasps to different bar rotations, thereby replicating previous results. The results indicate that 5- and 6-year-olds consistently use second-order planning in a dial rotation task, although this ability does not become apparent in bar rotation tasks. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of acute exercise on fear extinction in rats and exposure therapy in humans: Null findings from five experiments.

PubMed

Jacquart, Jolene; Roquet, Rheall F; Papini, Santiago; Powers, Mark B; Rosenfield, David; Smits, Jasper A J; Monfils, Marie-H

2017-08-01

Exposure therapy is an established learning-based intervention for the treatment of anxiety disorders with an average response rate of nearly 50%, leaving room for improvement. Emerging strategies to enhance exposure therapy in humans and fear extinction retention in animal models are primarily pharmacological. These approaches are limited as many patients report preferring non-pharmacological approaches in therapy. With general cognitive enhancement effects, exercise has emerged as a plausible non-pharmacological augmentation strategy. The present study tested the hypothesis that fear extinction and exposure therapy would be enhanced by a pre-training bout of exercise. We conducted four experiments with rats that involved a standardized conditioning and extinction paradigm and a manipulation of exercise. In a fifth experiment, we manipulated vigorous-intensity exercise prior to a standardized virtual reality exposure therapy session among adults with fear of heights. In experiments 1-4, exercise did not facilitate fear extinction, long-term memory, or fear relapse tests. In experiment 5, human participants showed an overall reduction in fear of heights but exercise did not enhance symptom improvement. Although acute exercise prior to fear extinction or exposure therapy, as operationalized in the present 5 studies, did not enhance outcomes, these results must be interpreted within the context of a broader literature that includes positive findings. Taken all together, this suggests that more research is necessary to identify optimal parameters and key individual differences so that exercise can be implemented successfully to treat anxiety disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

Obesity, growth hormone and exercise.

PubMed

Thomas, Gwendolyn A; Kraemer, William J; Comstock, Brett A; Dunn-Lewis, Courtenay; Maresh, Carl M; Volek, Jeff S

2013-09-01

Growth hormone (GH) is regulated, suppressed and stimulated by numerous physiological stimuli. However, it is believed that obesity disrupts the physiological and pathological factors that regulate, suppress or stimulate GH release. Pulsatile GH has been potently stimulated in healthy subjects by both aerobic and resistance exercise of the right intensity and duration. GH modulates fuel metabolism, reduces total fat mass and abdominal fat mass, and could be a potent stimulus of lipolysis when administered to obese individuals exogenously. Only pulsatile GH has been shown to augment adipose tissue lipolysis and, therefore, increasing pulsatile GH response may be a therapeutic target. This review discusses the factors that cause secretion of GH, how obesity may alter GH secretion and how both aerobic and resistance exercise stimulates GH, as well as how exercise of a specific intensity may be used as a stimulus for GH release in individuals who are obese. Only five prior studies have investigated exercise as a stimulus of endogenous GH in individuals who are obese. Based on prior literature, resistance exercise may provide a therapeutic target for releasing endogenous GH in individuals who are obese if specific exercise programme variables are utilized. Biological activity of GH indicates that this may be an important precursor to beneficial changes in body fat and lean tissue mass in obese individuals. However, additional research is needed including what molecular GH variants are acutely released and involved at target tissues as a result of different exercise stimuli and what specific exercise programme variables may serve to stimulate GH in individuals who are obese.

Parkin is required for exercise-induced mitophagy in muscle: impact of aging.

PubMed

Chen, Chris Chin Wah; Erlich, Avigail T; Crilly, Matthew J; Hood, David A

2018-05-29

The maintenance of muscle health with advancing age is dependent on mitochondrial homeostasis. While reductions in mitochondrial biogenesis have been observed with age, less is known regarding organelle degradation. Parkin is an E3 ubiquitin ligase implicated in mitophagy, but few studies have examined Parkin's contribution to mitochondrial turnover in muscle. Wild type (WT) and Parkin knockout (KO) mice were used to delineate a role for Parkin-mediated mitochondrial degradation in aged muscle, in concurrence with exercise. Aged animals exhibited declines in muscle mass and mitochondrial content, paralleled by a nuclear environment endorsing the transcriptional repression of mitochondrial biogenesis. Mitophagic signaling was enhanced following acute endurance exercise in young WT mice, but was abolished in the absence of Parkin. Basal mitophagy flux of the autophagosomal protein LC3II was augmented in aged animals, but did not increase additionally with exercise when compared to young animals. In the absence of Parkin, exercise increased the nuclear localization of PARIS, corresponding to a decrease in nuclear PGC-1α. Remarkably, exercise enhanced mitochondrial ubiquitination in both young WT and KO animals. This suggested compensation of alternative ubiquitin ligases that were, however, unable to restore the diminished exercise-induced mitophagy in KO mice. Under basal conditions, we demonstrated that Parkin was required for mitochondrial Mfn2 ubiquitination. We also observed an abrogation of exercise-induced mitophagy in aged muscle. Our results demonstrate that acute exercise-induced mitophagy is dependent on Parkin, and attenuated with age, which likely contributes to changes in mitochondrial content and quality in aging muscle.

Neural control of blood flow during exercise in human metabolic syndrome.

PubMed

Limberg, Jacqueline K; Morgan, Barbara J; Sebranek, Joshua J; Proctor, Lester T; Eldridge, Marlowe W; Schrage, William G

2014-09-01

α-Adrenergic-mediated vasoconstriction is greater during simulated exercise in animal models of metabolic syndrome (MetSyn) when compared with control animals. In an attempt to translate such findings to humans, we hypothesized that adults with MetSyn (n = 14, 35 ± 3 years old) would exhibit greater α-adrenergic responsiveness during exercise when compared with age-matched healthy control subjects (n = 16, 31 ± 3 years old). We measured muscle sympathetic nerve activity (MSNA; microneurography) and forearm blood flow (Doppler ultrasound) during dynamic forearm exercise (15% of maximal voluntary contraction). α-Adrenergic agonists (phenylephrine and clonidine) and an antagonist (phentolamine) were infused intra-arterially to assess α-adrenergic receptor responsiveness and restraint, respectively. Resting MSNA was ∼35% higher in adults with MetSyn (P < 0.05), but did not change in either group with dynamic exercise. Clonidine-mediated vasoconstriction was greater in adults with MetSyn (P < 0.01). Group differences in vascular responses to phenylephrine and phentolamine were not detected (P > 0.05). Interestingly, exercise-mediated vasodilatation was greater in MetSyn (P < 0.05). Adults with MetSyn exhibit greater resting MSNA and clonidine-mediated vasoconstriction, yet preserved functional sympatholysis and higher exercise blood flow during low-intensity hand-grip exercise when compared with age-matched healthy control subjects. These results suggest that adults with MetSyn exhibit compensatory vascular control mechanisms capable of preserving blood flow responses to exercise in the face of augmented sympathetic adrenergic activity. © 2014 The Authors. Experimental Physiology © 2014 The Physiological Society.

Feasibility of cardiopulmonary exercise testing and training using a robotics-assisted tilt table in dependent-ambulatory stroke patients.

PubMed

Saengsuwan, Jittima; Huber, Celine; Schreiber, Jonathan; Schuster-Amft, Corina; Nef, Tobias; Hunt, Kenneth J

2015-09-26

We evaluated the feasibility of an augmented robotics-assisted tilt table (RATT) for incremental cardiopulmonary exercise testing (CPET) and exercise training in dependent-ambulatory stroke patients. Stroke patients (Functional Ambulation Category ≤ 3) underwent familiarization, an incremental exercise test (IET) and a constant load test (CLT) on separate days. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and real-time visual feedback to guide the exercise work rate was used. Feasibility assessment considered technical feasibility, patient tolerability, and cardiopulmonary responsiveness. Eight patients (4 female) aged 58.3 ± 9.2 years (mean ± SD) were recruited and all completed the study. For IETs, peak oxygen uptake (V'O2peak), peak heart rate (HRpeak) and peak work rate (WRpeak) were 11.9 ± 4.0 ml/kg/min (45 % of predicted V'O2max), 117 ± 32 beats/min (72 % of predicted HRmax) and 22.5 ± 13.0 W, respectively. Peak ratings of perceived exertion (RPE) were on the range "hard" to "very hard". All 8 patients reached their limit of functional capacity in terms of either their cardiopulmonary or neuromuscular performance. A ventilatory threshold (VT) was identified in 7 patients and a respiratory compensation point (RCP) in 6 patients: mean V'O2 at VT and RCP was 8.9 and 10.7 ml/kg/min, respectively, which represent 75 % (VT) and 85 % (RCP) of mean V'O2peak. Incremental CPET provided sufficient information to satisfy the responsiveness criteria and identification of key outcomes in all 8 patients. For CLTs, mean steady-state V'O2 was 6.9 ml/kg/min (49 % of V'O2 reserve), mean HR was 90 beats/min (56 % of HRmax), RPEs were > 2, and all patients maintained the active work rate for 10 min: these values meet recommended intensity levels for bouts of training. The augmented RATT is deemed feasible for incremental cardiopulmonary exercise testing and exercise training in dependent-ambulatory stroke patients: the approach was found to be technically implementable, acceptable to the patients, and it showed substantial cardiopulmonary responsiveness. This work has clinical implications for patients with severe disability who otherwise are not able to be tested.

Endothelial dysfunction correlates with exaggerated exercise pressor response during whole body maximal exercise in chronic kidney disease.

PubMed

Downey, Ryan M; Liao, Peizhou; Millson, Erin C; Quyyumi, Arshed A; Sher, Salman; Park, Jeanie

2017-05-01

Chronic kidney disease (CKD) patients have exercise intolerance associated with increased cardiovascular mortality. Previous studies demonstrate that blood pressure (BP) and sympathetic nerve responses to handgrip exercise are exaggerated in CKD. These patients also have decreased nitric oxide (NO) bioavailability and endothelial dysfunction, which could potentially lead to an impaired ability to vasodilate during exercise. We hypothesized that CKD patients have exaggerated BP responses during maximal whole body exercise and that endothelial dysfunction correlates with greater exercise pressor responses in these patients. Brachial artery flow-mediated dilation (FMD) was assessed before maximal treadmill exercise in 56 participants: 38 CKD (56.7 ± 1.2 yr old, 38 men) and 21 controls (52.8 ± 1.8 yr old, 20 men). During maximal treadmill exercise, the slope-of-rise in systolic BP (+10.32 vs. +7.75 mmHg/stage, P < 0.001), mean arterial pressure (+3.50 vs. +2.63 mmHg/stage, P = 0.004), and heart rate (+11.87 vs. +10.69 beats·min -1 ·stage -1 , P = 0.031) was significantly greater in CKD compared with controls. Baseline FMD was significantly lower in CKD (2.76 ± 0.42% vs. 5.84 ± 0.97%, P = 0.008). Lower FMD values were significantly associated with a higher slope-of-rise in systolic BP (+11.05 vs. 8.71 mmHg/stage, P = 0.003) during exercise in CKD, as well as poorer exercise capacity measured as peak oxygen uptake (V̇o 2peak ; 19.47 ± 1.47 vs. 24.57 ± 1.51 ml·min -1 ·kg -1 , P < 0.001). These findings demonstrate that low FMD in CKD correlates with augmented BP responses during exercise and lower V̇o 2peak , suggesting that endothelial dysfunction may contribute to exaggerated exercise pressor responses and poor exercise capacity in CKD patients.

Upper-body resistance exercise augments vastus lateralis androgen receptor-DNA binding and canonical Wnt/β-catenin signaling compared to lower-body resistance exercise in resistance-trained men without an acute increase in serum testosterone.

PubMed

Spillane, Mike; Schwarz, Neil; Willoughby, Darryn S

2015-06-01

The purpose of the study was to determine the effect of single bouts of lower-body (LB) and upper- and lower-body (ULB) resistance exercise on serum testosterone concentrations and the effects on muscle testosterone, dihydrotestosterone (DHT), androgen receptor (AR) protein content, and AR-DNA binding. A secondary purpose was to determine the effects on serum wingless-type MMTV integration site (Wnt4) levels and skeletal muscle β-catenin content. In a randomized cross-over design, exercise bouts consisted of a LB and ULB protocol, and each bout was separated by 1 week. Blood and muscle samples were obtained before exercise and 3 and 24h post-exercise; blood samples were also obtained at 0.5, 1, and 2 h post-exercise. Statistical analyses were performed by separate two-way factorial analyses of variance (ANOVA) with repeated measures. No significant differences from baseline were observed in serum total and free testosterone and skeletal muscle testosterone and DHT with either protocol (p>0.05). AR protein was significantly increased at 3 h post-exercise and decreased at 24 h post-exercise for ULB, whereas AR-DNA binding was significantly increased at 3 and 24h post-exercise (p<0.05). In response to ULB, serum Wnt4 was significantly increased at 0.5, 1, and 2 h post-exercise (p<0.05) and β-catenin was significantly increased at 3 and 24 h post-exercise (p<0.05). It was concluded that, despite a lack of increase in serum testosterone and muscle androgen concentrations from either mode of resistance exercise, ULB resistance exercise increased Wnt4/β-catenin signaling and AR-DNA binding. Copyright © 2015 Elsevier Inc. All rights reserved.

Co-ingestion of carbohydrate and whey protein increases fasted rates of muscle protein synthesis immediately after resistance exercise in rats

PubMed Central

Wang, Wanyi; Ding, Zhenping; Solares, Geoffrey J.; Choi, Soon-Mi; Wang, Bo; Yoon, Aram; Farrar, Roger P.; Ivy, John L.

2017-01-01

The objective of the study was to investigate whether co-ingestion of carbohydrate and protein as compared with protein alone augments muscle protein synthesis (MPS) during early exercise recovery. Two months old rats performed 10 repetitions of ladder climbing with 75% of body weight attached to their tails. Placebo (PLA), whey protein (WP), or whey protein plus carbohydrate (CP) was then given to rats by gavage. An additional group of sedentary rats (SED) was used as controls. Blood samples were collected immediately and at either 1 or 2 h after exercise. The flexor hallucis longus muscle was excised at 1 or 2 h post exercise for analysis of MPS and related signaling proteins. MPS was significantly increased by CP compared with PLA (p<0.05), and approached significance compared with WP at 1 h post exercise (p = 0.08). CP yielded a greater phosphorylation of mTOR compared with SED and PLA at 1 h post exercise and SED and WP at 2 h post exercise. CP also increased phosphorylation of p70S6K compared with SED at 1 and 2 h post exercise. 4E-BP1 phosphorylation was inhibited by PLA at 1 h but elevated by WP and CP at 2 h post exercise relative to SED. The phosphorylation of AMPK was elevated by exercise at 1 h post exercise, and this elevated level was sustained only in the WP group at 2 h. The phosphorylation of Akt, GSK3, and eIF2Bε were unchanged by treatments. Plasma insulin was transiently increased by CP at 1 h post exercise. In conclusion, post-exercise CP supplementation increases MPS post exercise relative to PLA and possibly WP, which may have been mediated by greater activation of the mTOR signaling pathway. PMID:28296942

Exercise excess pressure and exercise-induced albuminuria in patients with type 2 diabetes mellitus.

PubMed

Climie, Rachel E D; Srikanth, Velandai; Keith, Laura J; Davies, Justin E; Sharman, James E

2015-05-01

Exercise-induced albuminuria is common in patients with type 2 diabetes mellitus (T2DM) in response to maximal exercise, but the response to light-moderate exercise is unclear. Patients with T2DM have abnormal central hemodynamics and greater propensity for exercise hypertension. This study sought to determine the relationship between light-moderate exercise central hemodynamics (including aortic reservoir and excess pressure) and exercise-induced albuminuria. Thirty-nine T2DM (62 ± 9 yr; 49% male) and 39 nondiabetic controls (53 ± 9 yr; 51% male) were examined at rest and during 20 min of light-moderate cycle exercise (30 W; 50 revolutions/min). Albuminuria was assessed by the albumin-creatinine ratio (ACR) at rest and 30 min postexercise. Hemodynamics recorded included brachial and central blood pressure (BP), aortic stiffness, augmented pressure (AP), aortic reservoir pressure, and excess pressure integral (Pexcess). There was no difference in ACR between groups before exercise (P > 0.05). Exercise induced a significant rise in ACR in T2DM but not controls (1.73 ± 1.43 vs. 0.53 ± 1.0 mg/mol, P = 0.002). All central hemodynamic variables were significantly higher during exercise in T2DM (i.e., Pexcess, systolic BP and AP; P < 0.01 all). In T2DM (but not controls), exercise Pexcess was associated with postexercise ACR (r = 0.51, P = 0.002), and this relationship was independent of age, sex, body mass index, heart rate, aortic stiffness, antihypertensive medication, and ambulatory daytime systolic BP (β = 0.003, P = 0.003). Light-moderate exercise induced a significant rise in ACR in T2DM, and this was independently associated with Pexcess, a potential marker of vascular dysfunction. These novel findings suggest that Pexcess could be important for appropriate renal function in T2DM. Copyright © 2015 the American Physiological Society.

Identifiability of Additive Actuator and Sensor Faults by State Augmentation

NASA Technical Reports Server (NTRS)

Joshi, Suresh; Gonzalez, Oscar R.; Upchurch, Jason M.

2014-01-01

A class of fault detection and identification (FDI) methods for bias-type actuator and sensor faults is explored in detail from the point of view of fault identifiability. The methods use state augmentation along with banks of Kalman-Bucy filters for fault detection, fault pattern determination, and fault value estimation. A complete characterization of conditions for identifiability of bias-type actuator faults, sensor faults, and simultaneous actuator and sensor faults is presented. It is shown that FDI of simultaneous actuator and sensor faults is not possible using these methods when all sensors have unknown biases. The fault identifiability conditions are demonstrated via numerical examples. The analytical and numerical results indicate that caution must be exercised to ensure fault identifiability for different fault patterns when using such methods.

Fear of movement modulates the feedforward motor control of the affected limb in complex regional pain syndrome (CRPS): A single-case study.

PubMed

Osumi, Michihiro; Sumitani, Masahiko; Otake, Yuko; Morioka, Shu

2018-01-01

Pain-related fear can exacerbate physical disability and pathological pain in complex regional pain syndrome (CRPS) patients. We conducted a kinematic analysis of grasping movements with a pediatric patient suffering from CRPS in an upper limb to investigate how pain-related fear affects motor control. Using a three-dimensional measurement system, we recorded the patient's movement while grasping three vertical bars of different diameters (thin, middle, thick) with the affected and intact hands. We analyzed the maximum grasp distance between the thumb and the index finger (MGD), the peak velocity of the grasp movement (PV), and the time required for the finger opening phase (TOP) and closing phase (TCP). Consequently, the MGD and PV of grasp movements in the affected hand were significantly smaller than those of the intact hand when grasping the middle and thick bars. This might reflect pain-related fear against visual information of the target size which evokes sensation of difficulty in opening fingers widely to grasp the middle and thick bars. Although MGD and PV increased with target size, the TOP was longer in the affected hand when grasping the thick bar. These findings indicate that pain-related fear impairs motor commands that are sent to the musculoskeletal system, subsequently disrupting executed movements and their sensory feedback. Using kinematic analysis, we objectively demonstrated that pain-related fear affects the process of sending motor commands towards the musculoskeletal system in the CRPS-affected hand, providing a possible explanatory model of pathological pain. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Neural Correlates of Grasping in Left-Handers: When Handedness Does Not Matter.

PubMed

Begliomini, Chiara; Sartori, Luisa; Di Bono, Maria G; Budisavljević, Sanja; Castiello, Umberto

2018-01-01

Neurophysiological studies showed that in macaques, grasp-related visuomotor transformations are supported by a circuit involving the anterior part of the intraparietal sulcus, the ventral and the dorsal region of the premotor area. In humans, a similar grasp-related circuit has been revealed by means of neuroimaging techniques. However, the majority of "human" studies considered movements performed by right-handers only, leaving open the question of whether the dynamics underlying motor control during grasping is simply reversed in left-handers with respect to right-handers or not. To address this question, a group of left-handed participants has been scanned with functional magnetic resonance imaging while performing a precision grasping task with the left or the right hand. Dynamic causal modeling was used to assess how brain regions of the two hemispheres contribute to grasping execution and whether the intra- and inter-hemispheric connectivity is modulated by the choice of the performing hand. Results showed enhanced inter-hemispheric connectivity between anterior intraparietal and dorsal premotor cortices during grasping execution with the left dominant hand (LDH) (e.g., right hemisphere) compared to the right (e.g., left hemisphere). These findings suggest that that the left hand, although dominant and theoretically more skilled in left handers, might need additional resources in terms of the visuomotor control and on-line monitoring to accomplish a precision grasping movement. The results are discussed in light of theories on the modulation of parieto-frontal networks during the execution of prehensile movements, providing novel evidence supporting the hypothesis of a handedness-independent specialization of the left hemisphere in visuomotor control.

Patterns of muscle activity underlying object-specific grasp by the macaque monkey.

PubMed

Brochier, T; Spinks, R L; Umilta, M A; Lemon, R N

2004-09-01

During object grasp, a coordinated activation of distal muscles is required to shape the hand in relation to the physical properties of the object. Despite the fundamental importance of the grasping action, little is known of the muscular activation patterns that allow objects of different sizes and shapes to be grasped. In a study of two adult macaque monkeys, we investigated whether we could distinguish between EMG activation patterns associated with grasp of 12 differently shaped objects, chosen to evoke a wide range of grasping postures. Each object was mounted on a horizontal shuttle held by a weak spring (load force 1-2 N). Objects were located in separate sectors of a "carousel," and inter-trial rotation of the carousel allowed sequential presentation of the objects in pseudorandom order. EMG activity from 10 to 12 digit, hand, and arm muscles was recorded using chronically implanted electrodes. We show that the grasp of different objects was characterized by complex but distinctive patterns of EMG activation. Cluster analysis shows that these object-related EMG patterns were specific and consistent enough to identify the object unequivocally from the EMG recordings alone. EMG-based object identification required a minimum of six EMGs from simultaneously recorded muscles. EMG patterns were consistent across recording sessions in a given monkey but showed some differences between animals. These results identify the specific patterns of activity required to achieve distinct hand postures for grasping, and they open the way to our understanding of how these patterns are generated by the central motor network.

Biclustering of gene expression data using reactive greedy randomized adaptive search procedure

PubMed Central

Dharan, Smitha; Nair, Achuthsankar S

2009-01-01

Background Biclustering algorithms belong to a distinct class of clustering algorithms that perform simultaneous clustering of both rows and columns of the gene expression matrix and can be a very useful analysis tool when some genes have multiple functions and experimental conditions are diverse. Cheng and Church have introduced a measure called mean squared residue score to evaluate the quality of a bicluster and has become one of the most popular measures to search for biclusters. In this paper, we review basic concepts of the metaheuristics Greedy Randomized Adaptive Search Procedure (GRASP)-construction and local search phases and propose a new method which is a variant of GRASP called Reactive Greedy Randomized Adaptive Search Procedure (Reactive GRASP) to detect significant biclusters from large microarray datasets. The method has two major steps. First, high quality bicluster seeds are generated by means of k-means clustering. In the second step, these seeds are grown using the Reactive GRASP, in which the basic parameter that defines the restrictiveness of the candidate list is self-adjusted, depending on the quality of the solutions found previously. Results We performed statistical and biological validations of the biclusters obtained and evaluated the method against the results of basic GRASP and as well as with the classic work of Cheng and Church. The experimental results indicate that the Reactive GRASP approach outperforms the basic GRASP algorithm and Cheng and Church approach. Conclusion The Reactive GRASP approach for the detection of significant biclusters is robust and does not require calibration efforts. PMID:19208127

Afterrise: Deep Body Temperature Following Exercise

DTIC Science & Technology

1992-03-01

Egalement, les effets de la posture et des v~tements durant la recuperation et la temperature de la salle de recuperation furent examines. Cinq hommes se...chemise a manches courtes). Les temperatures rectales et de la peau furent mesurees A chaque minute durant les exercices et la r~cup~ration affectaient...overgarment. RESUME Cette etude fut entreprise pour documenter l’augmentation continue de la temperature rectale apres exercice dans la chaleur

The hematocrit paradox--how does blood doping really work?

PubMed

Böning, D; Maassen, N; Pries, A

2011-04-01

The wide-spread assumption that doping with erythropoietin or blood transfusion is only effective by increasing arterial blood O2 content because of rising hematocrit is not self-evident. "Natural blood dopers" (horses, dogs) increase both hematocrit and circulating blood volume during exercise by releasing stored erythrocytes from the spleen. Improvement of aerobic performance by augmenting hemoglobin concentration may be expected until the optimal hematocrit is reached; above this value maximal cardiac output declines due to the steep increase of blood viscosity. Therefore an enlarged blood oxygen content might only be useful if the normal hematocrit of man during exercise is suboptimal. However, recent studies suggest that cardiac power rises after erythropoietin allowing an unchanged cardiac output in spite of increased viscosity. Other factors underlying improved performance after blood doping might be: augmented diffusion capacity for oxygen in lungs and tissues, increased percentage of young red cells with good functional properties (after erythropoietin), increased buffer capacity, increase of blood volume, vasoconstriction, reduced damage by radicals, mood improvement by cerebral effects of erythropoietin. Also the importance of placebo is unknown since double-blind studies are rare. It is suggested that blood doping has multifactorial effects not restricted to the increase in arterial oxygen content. © Georg Thieme Verlag KG Stuttgart · New York.

Size, shape, and stamina: the impact of left ventricular geometry on exercise capacity.

PubMed

Lam, Carolyn S P; Grewal, Jasmine; Borlaug, Barry A; Ommen, Steve R; Kane, Garvan C; McCully, Robert B; Pellikka, Patricia A

2010-05-01

Although several studies have examined the cardiac functional determinants of exercise capacity, few have investigated the effects of structural remodeling. The current study evaluated the association between cardiac geometry and exercise capacity. Subjects with ejection fraction > or = 50% and no valvular disease, myocardial ischemia, or arrhythmias were identified from a large prospective exercise echocardiography database. Left ventricular mass index and relative wall thickness were used to classify geometry into normal, concentric remodeling, eccentric hypertrophy, and concentric hypertrophy. All of the subjects underwent symptom-limited treadmill exercise according to standard Bruce protocol. Maximal exercise tolerance was measured in metabolic equivalents. Of 366 (60+/-14 years; 57% male) subjects, 166 (45%) had normal geometry, 106 (29%) had concentric remodeling, 40 (11%) had eccentric hypertrophy, and 54 (15%) had concentric hypertrophy. Geometry was related to exercise capacity: in descending order, the maximum achieved metabolic equivalents were 9.9+/-2.8 in normal, 8.9+/-2.6 in concentric remodeling, 8.6+/-3.1 in eccentric hypertrophy, and 8.0+/-2.7 in concentric hypertrophy (all P<0.02 versus normal). Left ventricular mass index and relative wall thickness were negatively correlated with exercise tolerance in metabolic equivalents (r=-0.14; P=0.009 and r=-0.21; P<0.001, respectively). Augmentation of heart rate and ejection fraction with exercise were blunted in concentric hypertrophy compared with normal, even after adjusting for medications. In conclusion, the pattern of ventricular remodeling is related to exercise capacity among low-risk adults. Subjects with concentric hypertrophy display the greatest limitation, and this is related to reduced systolic and chronotropic reserve. Reverse remodeling strategies may prevent or treat functional decline in patients with structural heart disease.

Size, Shape and Stamina: The Impact of Left Ventricular Geometry on Exercise Capacity

PubMed Central

Lam, Carolyn S.P.; Grewal, Jasmine; Borlaug, Barry A.; Ommen, Steve R.; Kane, Garvan C.; McCully, Robert B.; Pellikka, Patricia A.

2010-01-01

While several studies have examined the cardiac functional determinants of exercise capacity, few have investigated the effects of structural remodeling. The current study evaluated the association between cardiac geometry and exercise capacity. Subjects with ejection fraction ≥ 50% and no valvular disease, myocardial ischemia or arrhythmias were identified from a large prospective exercise echocardiography database. Left ventricular mass index and relative wall thickness were used to classify geometry into normal, concentric remodeling, eccentric hypertrophy and concentric hypertrophy. All subjects underwent symptom-limited treadmill exercise according to standard Bruce protocol. Maximal exercise tolerance was measured in metabolic equivalents. Of 366 (60±14 years; 57% male) subjects, 166(45%) had normal geometry, 106(29%) had concentric remodeling, 40(11%) had eccentric hypertrophy and 54(15%) had concentric hypertrophy. Geometry was related to exercise capacity: in descending order, the maximum achieved metabolic equivalents was 9.9±2.8 in normal, 8.9±2.6 in concentric remodeling, 8.6±3.1 in eccentric hypertrophy and 8.0±2.7 in concentric hypertrophy (all p<0.02 vs normal). Left ventricular mass index and relative wall thickness were negatively correlated with exercise tolerance in metabolic equivalents (r= -0.14; p=0.009 and r= -0.21; p<0.001, respectively). Augmentation of heart rate and ejection fraction with exercise were blunted in concentric hypertrophy compared to normal, even after adjusting for medications. In conclusion, the pattern of ventricular remodeling is related to exercise capacity among low-risk adults. Subjects with concentric hypertrophy display the greatest limitation and this is related to reduced systolic and chronotropic reserve. Reverse remodeling strategies may prevent or treat functional decline in patients with structural heart disease. PMID:20215563

Atorvastatin Increases Exercise Leg Blood Flow in Healthy Adults

PubMed Central

Parker, Beth A.; Capizzi, Jeffrey A.; Augeri, Amanda L.; Grimaldi, Adam S.; White, C. Michael; Thompson, Paul D.

2011-01-01

OBJECTIVES We sought to examine the effect of atorvastatin therapy on exercise leg blood flow in healthy middle-aged and older, men and women. BACKGROUND The vasodilatory response to exercise decreases in humans with aging and disease and this reduction may contribute to reduced exercise capacity. METHODS We used a double-blind, randomly assigned, placebo-controlled protocol to assess the effect of atorvastatin treatment on exercising leg hemodynamics. We measured femoral artery blood flow (FBF) using Doppler ultrasound and calculated femoral vascular conductance (FVC) from brachial mean arterial pressure (MAP) before and during single knee-extensor exercise in healthy adults (ages 40–71) before (PRE) and after (POST) 6 months of 80 mg atorvastatin (A: 14 men, 16 women) or placebo (P: 14 men, 22 women) treatment. FBF and FVC were normalized to exercise power output and estimated quadriceps muscle mass. RESULTS Atorvastatin reduced LDL cholesterol by approximately 50%, but not in the placebo group (p < 0.01). Atorvastatin also increased exercise FBF from 44.2 ± 19.0 to 51.4 ± 22.0 mL/min/W/kg muscle whereas FBF in the placebo group was unchanged (40.1 ± 16.0 vs 39.5 ± 16.1) (p <0.01). FVC also increased with atorvastatin from 0.5 ± 0.2 to. 0.6 ± 0.2 mL/min/mmHg/W/kg muscle, but not in the placebo subjects (P: 0.4 ± 0.2 vs 0.4 ± 0.2) ( p < 0.01). CONCLUSIONS High-dose atorvastatin augments exercising leg hyperemia. Statins may mitigate reductions in the exercise vasodilatory response in humans that are associated with aging and disease. PMID:22018642

The effect of acute maximal exercise on postexercise hemodynamics and central arterial stiffness in obese and normal-weight individuals.

PubMed

Bunsawat, Kanokwan; Ranadive, Sushant M; Lane-Cordova, Abbi D; Yan, Huimin; Kappus, Rebecca M; Fernhall, Bo; Baynard, Tracy

2017-04-01

Central arterial stiffness is associated with incident hypertension and negative cardiovascular outcomes. Obese individuals have higher central blood pressure (BP) and central arterial stiffness than their normal-weight counterparts, but it is unclear whether obesity also affects hemodynamics and central arterial stiffness after maximal exercise. We evaluated central hemodynamics and arterial stiffness during recovery from acute maximal aerobic exercise in obese and normal-weight individuals. Forty-six normal-weight and twenty-one obese individuals underwent measurements of central BP and central arterial stiffness at rest and 15 and 30 min following acute maximal exercise. Central BP and normalized augmentation index (AIx@75) were derived from radial artery applanation tonometry, and central arterial stiffness was obtained via carotid-femoral pulse wave velocity (cPWV) and corrected for central mean arterial pressure (cPWV/cMAP). Central arterial stiffness increased in obese individuals but decreased in normal-weight individuals following acute maximal exercise, after adjusting for fitness. Obese individuals also exhibited an overall higher central BP ( P  <   0.05), with no exercise effect. The increase in heart rate was greater in obese versus normal-weight individuals following exercise ( P  <   0.05), but there was no group differences or exercise effect for AIx@75 In conclusion, obese (but not normal-weight) individuals increased central arterial stiffness following acute maximal exercise. An assessment of arterial stiffness response to acute exercise may serve as a useful detection tool for subclinical vascular dysfunction. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Comparison of Watermelon and Carbohydrate Beverage on Exercise-Induced Alterations in Systemic Inflammation, Immune Dysfunction, and Plasma Antioxidant Capacity

PubMed Central

Shanely, R. Andrew; Nieman, David C.; Perkins-Veazie, Penelope; Henson, Dru A.; Meaney, Mary P.; Knab, Amy M.; Cialdell-Kam, Lynn

2016-01-01

Consuming carbohydrate- and antioxidant-rich fruits during exercise as a means of supporting and enhancing both performance and health is of interest to endurance athletes. Watermelon (WM) contains carbohydrate, lycopene, l-citrulline, and l-arginine. WM may support exercise performance, augment antioxidant capacity, and act as a countermeasure to exercise-induced inflammation and innate immune changes. Trained cyclists (n = 20, 48 ± 2 years) participated in a randomized, placebo controlled, crossover study. Subjects completed two 75 km cycling time trials after either 2 weeks ingestion of 980 mL/day WM puree or no treatment. Subjects drank either WM puree containing 0.2 gm/kg carbohydrate or a 6% carbohydrate beverage every 15 min during the time trials. Blood samples were taken pre-study and pre-, post-, 1 h post-exercise. WM ingestion versus no treatment for 2-weeks increased plasma l-citrulline and l-arginine concentrations (p < 0.0125). Exercise performance did not differ between WM puree or carbohydrate beverage trials (p > 0.05), however, the rating of perceived exertion was greater during the WM trial (p > 0.05). WM puree versus carbohydrate beverage resulted in a similar pattern of increase in blood glucose, and greater increases in post-exercise plasma antioxidant capacity, l-citrulline, l-arginine, and total nitrate (all p < 0.05), but without differences in systemic markers of inflammation or innate immune function. Daily WM puree consumption fully supported the energy demands of exercise, and increased post-exercise blood levels of WM nutritional components (l-citrulline and l-arginine), antioxidant capacity, and total nitrate, but without an influence on post-exercise inflammation and changes in innate immune function. PMID:27556488

An increase in prefrontal oxygenation at the start of voluntary cycling exercise was observed independently of exercise effort and muscle mass.

PubMed

Asahara, Ryota; Endo, Kana; Liang, Nan; Matsukawa, Kanji

2018-05-31

We have reported using near-infrared spectroscopy that an increase in prefrontal oxygenated-hemoglobin concentration (Oxy-Hb) at the start of cycling exercise has relation to central command, defined as a feedforward signal descending from higher brain centers. The final output of central command evokes the exercise effort-dependent cardiovascular responses. If the prefrontal cortex may output the final signal of central command toward the autonomic nervous system, the prefrontal oxygenation should increase depending on exercise effort. To test the hypothesis, we investigated the effects of exercise intensity and muscle mass on prefrontal oxygenation in 13 subjects. The subjects performed one- or two-legged cycling at various relative intensities for 1 min. The prefrontal Oxy-Hb and cardiovascular variables were simultaneously measured during exercise. The increase in cardiac output and the decrease in total peripheral resistance at the start of one- and two-legged cycling were augmented in proportion to exercise intensity and muscle mass recruitment. The prefrontal Oxy-Hb increased at the start of voluntary cycling, while such increase was not developed during passive cycling. Mental imagery of cycling also increased the prefrontal Oxy-Hb, concomitantly with peripheral muscle vasodilatation. However, the increase in prefrontal Oxy-Hb at the start of voluntary cycling seemed independent of exercise intensity and muscle mass recruitment. It is likely that the increased prefrontal activity at the start of cycling exercise is not representative of the final output signal of central command itself toward the autonomic nervous system but may trigger neuronal activity in the caudal brain responsible for the generation of central command.

Exercise training increases basal tone in arterioles distal to chronic coronary occlusion

PubMed Central

Heaps, Cristine L.; Mattox, Mildred L.; Kelly, Katherine A.; Meininger, Cynthia J.; Parker, Janet L.

2014-01-01

Endurance exercise training increases basal active tone in coronary arteries and enhances myogenic tone in coronary arterioles of control animals. Paradoxically, exercise training has also been shown to augment nitric oxide production and nitric oxide-mediated relaxation in coronary arterioles. The purpose of the present study was to examine the effect of exercise training on basal active tone of arterioles (~150 µm ID) isolated from the collateral-dependent region of hearts exposed to chronic coronary occlusion. Ameroid occluders were surgically placed around the proximal left circumflex coronary artery of miniature swine. Arterioles were isolated from both the collateral-dependent and nonoccluded myocardial regions of sedentary (pen confined) and exercise-trained (treadmill run; 14 wk) pigs. Coronary tone was studied in isolated arterioles using microvessel myographs and standard isometric techniques. Exposure to nominally Ca2+-free external solution reduced resting tension in all arterioles; decreases were most profound (P < 0.05) in arterioles from the collateral-dependent region of exercise-trained animals. Furthermore, nitric oxide synthase (NOS) inhibition (Nω-nitro-l-arginine methylester; 100 µM) unmasked markedly increased nitric oxide-sensitive tone in arterioles from the collateral-dependent region of exercise-trained swine. Blockade of K+ channels revealed significantly enhanced K+ channel contribution to basal tone in collateral-dependent arterioles of exercise-trained pigs. Protein content of endothelial NOS (eNOS) and phosphorylated eNOS (pS1179), determined by immunoblot, was elevated in arterioles from exercise-trained animals with the greatest effect in collateral-dependent vasculature. Taken together, we demonstrate the interaction of opposing exercise training-enhanced arteriolar basal active tone, nitric oxide production, and K+ channel activity in chronic coronary occlusion, potentially enhancing the capacity to regulate blood flow to collateral-dependent myocardium. PMID:16243909

Comparison of Watermelon and Carbohydrate Beverage on Exercise-Induced Alterations in Systemic Inflammation, Immune Dysfunction, and Plasma Antioxidant Capacity.

PubMed

Shanely, R Andrew; Nieman, David C; Perkins-Veazie, Penelope; Henson, Dru A; Meaney, Mary P; Knab, Amy M; Cialdell-Kam, Lynn

2016-08-22

Consuming carbohydrate- and antioxidant-rich fruits during exercise as a means of supporting and enhancing both performance and health is of interest to endurance athletes. Watermelon (WM) contains carbohydrate, lycopene, l-citrulline, and l-arginine. WM may support exercise performance, augment antioxidant capacity, and act as a countermeasure to exercise-induced inflammation and innate immune changes. Trained cyclists (n = 20, 48 ± 2 years) participated in a randomized, placebo controlled, crossover study. Subjects completed two 75 km cycling time trials after either 2 weeks ingestion of 980 mL/day WM puree or no treatment. Subjects drank either WM puree containing 0.2 gm/kg carbohydrate or a 6% carbohydrate beverage every 15 min during the time trials. Blood samples were taken pre-study and pre-, post-, 1 h post-exercise. WM ingestion versus no treatment for 2-weeks increased plasma l-citrulline and l-arginine concentrations (p < 0.0125). Exercise performance did not differ between WM puree or carbohydrate beverage trials (p > 0.05), however, the rating of perceived exertion was greater during the WM trial (p > 0.05). WM puree versus carbohydrate beverage resulted in a similar pattern of increase in blood glucose, and greater increases in post-exercise plasma antioxidant capacity, l-citrulline, l-arginine, and total nitrate (all p < 0.05), but without differences in systemic markers of inflammation or innate immune function. Daily WM puree consumption fully supported the energy demands of exercise, and increased post-exercise blood levels of WM nutritional components (l-citrulline and l-arginine), antioxidant capacity, and total nitrate, but without an influence on post-exercise inflammation and changes in innate immune function.

Adaptive Force Control in Grasping as a Function of Level of Developmental Disability

ERIC Educational Resources Information Center

Sprague, R. L.; Deutsch, K. M.; Newell, K. M.

2009-01-01

Background: The adaptation to the task demands of grasping (grip mode and object mass) was investigated as a function of level of developmental disability. Methods: Subjects grasped objects of different grip widths and masses that were instrumented to record grip forces. Results: Proportionally, fewer participants from the profound compared with…

Short-Term Plasticity of the Visuomotor Map during Grasping Movements in Humans

ERIC Educational Resources Information Center

Safstrom, Daniel; Edin, Benoni B.

2005-01-01

During visually guided grasping movements, visual information is transformed into motor commands. This transformation is known as the "visuomotor map." To investigate limitations in the short-term plasticity of the visuomotor map in normal humans, we studied the maximum grip aperture (MGA) during the reaching phase while subjects grasped objects…

Extending the Cortical Grasping Network: Pre-supplementary Motor Neuron Activity During Vision and Grasping of Objects.

PubMed

Lanzilotto, Marco; Livi, Alessandro; Maranesi, Monica; Gerbella, Marzio; Barz, Falk; Ruther, Patrick; Fogassi, Leonardo; Rizzolatti, Giacomo; Bonini, Luca

2016-12-01

Grasping relies on a network of parieto-frontal areas lying on the dorsolateral and dorsomedial parts of the hemispheres. However, the initiation and sequencing of voluntary actions also requires the contribution of mesial premotor regions, particularly the pre-supplementary motor area F6. We recorded 233 F6 neurons from 2 monkeys with chronic linear multishank neural probes during reaching-grasping visuomotor tasks. We showed that F6 neurons play a role in the control of forelimb movements and some of them (26%) exhibit visual and/or motor specificity for the target object. Interestingly, area F6 neurons form 2 functionally distinct populations, showing either visually-triggered or movement-related bursts of activity, in contrast to the sustained visual-to-motor activity displayed by ventral premotor area F5 neurons recorded in the same animals and with the same task during previous studies. These findings suggest that F6 plays a role in object grasping and extend existing models of the cortical grasping network. © The Author 2016. Published by Oxford University Press.

Don/doff support stand for use with rear entry space suits

NASA Technical Reports Server (NTRS)

Kosmo, Joseph J. (Inventor); Tri, Terry O. (Inventor); Spenny, William E. (Inventor); West, Philip R. (Inventor)

1988-01-01

A don/doff support stand for use with rear entry space suits is disclosed. The support stand is designed for use in one-g environments; however, certain features of the stand can be used on future spacecraft, lunar, or planetary bases. The present invention has a retainer which receives a protrucing lug fixed on the torso section of the space suit. When the lug is locked in the retainer, the space suit is held in a generally upright position. In a one-g environment a portable ladder is positioned adjacent to the rear entry of the space suit supported by the stand. The astronaut climbs up the ladder and grasps a hand bar assembly positioned above the rear entry. The astronaut then slips his legs through the open rear entry and down into the abdominal portion of the suite. The astronaut then lowers himself fully into the suit. The portable ladder is then removed and the astronaut can close the rear entry door. The lug is then disengaged from the retainer and the astronaut is free to engage in training exercises in the suit. When suit use is over, the astronaut returns to the stand and inserts the lug into the retainer. A technician repositions the ladder. The astronaut opens the rear entry door, grasps the hand bar assembly and does a chin-up to extricate himself from the suit. The astronaut climbs down the movable ladder while the suit is supported by the stand.

Don/Doff support stand for use with rear entry space suits

NASA Technical Reports Server (NTRS)

Kosmo, Joseph J. (Inventor); Tri, Terry O. (Inventor); Spenny, William E. (Inventor); West, Philip R. (Inventor)

1989-01-01

A don/doff support stand for use with rear entry space suits is disclosed. The support stand is designed for use in one-g environments; however, certain features of the stand can be used on future space-craft, lunar or planetary bases. The present invention has a retainer which receives a protruding lug fixed on the torso section of the space suit. When the lug is locked in the retainer, the space suit is held in a generally upright position. In a one-g environment a portable ladder is positioned adjacent to the rear entry of the space suit supported by the stand. The astronaut climbs up the ladder and grasps a hand bar assembly positioned above the rear entry. The astronaut then slips his legs through the open rear entry and down into the abdominal portion of the suit. The astronaut then lowers himself fully into the suit. The portable ladder is then removed and the astronaut can close the rear entry door. The lug is then disengaged from the retainer and the astronaut is free to engage in training exercises in the suit. When suit use is over, the astronaut returns to the stand and inserts the lug into the retainer. A technician repositions the ladder. The astronaut opens the rear entry door, grasps the hand bar assembly and does a chin-up to extricate himself from the suit. The astronaut climbs down the movable ladder while the suit is supported by the stand.

Augmented Go/No-Go Task: Mouse Cursor Motion Measures Improve ADHD Symptom Assessment in Healthy College Students

PubMed Central

Leontyev, Anton; Sun, Stanley; Wolfe, Mary; Yamauchi, Takashi

2018-01-01

Attention deficit/hyperactivity disorder (ADHD) is frequently characterized as a disorder of executive function (EF). However, behavioral tests of EF, such as go/No-go tasks, often fail to grasp the deficiency in EF revealed by questionnaire-based measures. This inability is usually attributed to questionnaires and behavioral tasks assessing different constructs of EFs. We propose an additional explanation for this discrepancy. We hypothesize that this problem stems from the lack of dynamic assessment of decision-making (e.g., continuous monitoring of motor behavior such as velocity and acceleration in choice reaching) in classical versions of behavioral tasks. We test this hypothesis by introducing dynamic assessment in the form of mouse motion in a go/No-go task. Our results indicate that, among healthy college students, self-report measures of ADHD symptoms become strongly associated with performance in behavioral tasks when continuous assessment (e.g., acceleration in the mouse-cursor motion) is introduced. PMID:29695985

Augmented Go/No-Go Task: Mouse Cursor Motion Measures Improve ADHD Symptom Assessment in Healthy College Students.

PubMed

Leontyev, Anton; Sun, Stanley; Wolfe, Mary; Yamauchi, Takashi

2018-01-01

Attention deficit/hyperactivity disorder (ADHD) is frequently characterized as a disorder of executive function (EF). However, behavioral tests of EF, such as go/No-go tasks, often fail to grasp the deficiency in EF revealed by questionnaire-based measures. This inability is usually attributed to questionnaires and behavioral tasks assessing different constructs of EFs. We propose an additional explanation for this discrepancy. We hypothesize that this problem stems from the lack of dynamic assessment of decision-making (e.g., continuous monitoring of motor behavior such as velocity and acceleration in choice reaching) in classical versions of behavioral tasks. We test this hypothesis by introducing dynamic assessment in the form of mouse motion in a go/No-go task. Our results indicate that, among healthy college students, self-report measures of ADHD symptoms become strongly associated with performance in behavioral tasks when continuous assessment (e.g., acceleration in the mouse-cursor motion) is introduced.

Mirror neurons encode the subjective value of an observed action.

PubMed

Caggiano, Vittorio; Fogassi, Leonardo; Rizzolatti, Giacomo; Casile, Antonino; Giese, Martin A; Thier, Peter

2012-07-17

Objects grasped by an agent have a value not only for the acting agent, but also for an individual observing the grasping act. The value that the observer attributes to the object that is grasped can be pivotal for selecting a possible behavioral response. Mirror neurons in area F5 of the monkey premotor cortex have been suggested to play a crucial role in the understanding of action goals. However, it has not been addressed if these neurons are also involved in representing the value of the grasped object. Here we report that observation-related neuronal responses of F5 mirror neurons are indeed modulated by the value that the monkey associates with the grasped object. These findings suggest that during action observation F5 mirror neurons have access to key information needed to shape the behavioral responses of the observer.

An instrumented glove for grasp specification in virtual-reality-based point-and-direct telerobotics.

PubMed

Yun, M H; Cannon, D; Freivalds, A; Thomas, G

1997-10-01

Hand posture and force, which define aspects of the way an object is grasped, are features of robotic manipulation. A means for specifying these grasping "flavors" has been developed that uses an instrumented glove equipped with joint and force sensors. The new grasp specification system will be used at the Pennsylvania State University (Penn State) in a Virtual Reality based Point-and-Direct (VR-PAD) robotics implementation. Here, an operator gives directives to a robot in the same natural way that human may direct another. Phrases such as "put that there" cause the robot to define a grasping strategy and motion strategy to complete the task on its own. In the VR-PAD concept, pointing is done using virtual tools such that an operator can appear to graphically grasp real items in live video. Rather than requiring full duplication of forces and kinesthetic movement throughout a task as is required in manual telemanipulation, hand posture and force are now specified only once. The grasp parameters then become object flavors. The robot maintains the specified force and hand posture flavors for an object throughout the task in handling the real workpiece or item of interest. In the Computer integrated Manufacturing (CIM) Laboratory at Penn State, hand posture and force data were collected for manipulating bricks and other items that require varying amounts of force at multiple pressure points. The feasibility of measuring desired grasp characteristics was demonstrated for a modified Cyberglove impregnated with Force-Sensitive Resistor (FSR) (pressure sensors in the fingertips. A joint/force model relating the parameters of finger articulation and pressure to various lifting tasks was validated for the instrumented "wired" glove. Operators using such a modified glove may ultimately be able to configure robot grasping tasks in environments involving hazardous waste remediation, flexible manufacturing, space operations and other flexible robotics applications. In each case, the VR-PAD approach will finesse the computational and delay problems of real-time multiple-degree-of-freedom force feedback telemanipulation.

Getting a grip on reality: Grasping movements directed to real objects and images rely on dissociable neural representations.

PubMed

Freud, Erez; Macdonald, Scott N; Chen, Juan; Quinlan, Derek J; Goodale, Melvyn A; Culham, Jody C

2018-01-01

In the current era of touchscreen technology, humans commonly execute visually guided actions directed to two-dimensional (2D) images of objects. Although real, three-dimensional (3D), objects and images of the same objects share high degree of visual similarity, they differ fundamentally in the actions that can be performed on them. Indeed, previous behavioral studies have suggested that simulated grasping of images relies on different representations than actual grasping of real 3D objects. Yet the neural underpinnings of this phenomena have not been investigated. Here we used functional magnetic resonance imaging (fMRI) to investigate how brain activation patterns differed for grasping and reaching actions directed toward real 3D objects compared to images. Multivoxel Pattern Analysis (MVPA) revealed that the left anterior intraparietal sulcus (aIPS), a key region for visually guided grasping, discriminates between both the format in which objects were presented (real/image) and the motor task performed on them (grasping/reaching). Interestingly, during action planning, the representations of real 3D objects versus images differed more for grasping movements than reaching movements, likely because grasping real 3D objects involves fine-grained planning and anticipation of the consequences of a real interaction. Importantly, this dissociation was evident in the planning phase, before movement initiation, and was not found in any other regions, including motor and somatosensory cortices. This suggests that the dissociable representations in the left aIPS were not based on haptic, motor or proprioceptive feedback. Together, these findings provide novel evidence that actions, particularly grasping, are affected by the realness of the target objects during planning, perhaps because real targets require a more elaborate forward model based on visual cues to predict the consequences of real manipulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analysis of Hand and Wrist Postural Synergies in Tolerance Grasping of Various Objects

PubMed Central

Liu, Yuan; Jiang, Li; Yang, Dapeng; Liu, Hong

2016-01-01

Human can successfully grasp various objects in different acceptable relative positions between human hand and objects. This grasp functionality can be described as the grasp tolerance of human hand, which is a significant functionality of human grasp. To understand the motor control of human hand completely, an analysis of hand and wrist postural synergies in tolerance grasping of various objects is needed. Ten healthy right-handed subjects were asked to perform the tolerance grasping with right hand using 6 objects of different shapes, sizes and relative positions between human hand and objects. Subjects were wearing CyberGlove attaching motion tracker on right hand, allowing a measurement of the hand and wrist postures. Correlation analysis of joints and inter-joint/inter-finger modules were carried on to explore the coordination between joints or modules. As the correlation between hand and wrist module is not obvious in tolerance grasping, individual analysis of wrist synergies would be more practical. In this case, postural synergies of hand and wrist were then presented separately through principal component analysis (PCA), expressed through the principal component (PC) information transmitted ratio, PC elements distribution and reconstructed angle error of joints. Results on correlation comparison of different module movements can be well explained by the influence factors of the joint movement correlation. Moreover, correlation analysis of joints and modules showed the wrist module had the lowest correlation among all inter-finger and inter-joint modules. Hand and wrist postures were both sufficient to be described by a few principal components. In terms of the PC elements distribution of hand postures, compared with previous investigations, there was a greater proportion of movement in the thumb joints especially the interphalangeal (IP) and opposition rotation (ROT) joint. The research could serve to a complete understanding of hand grasp, and the design, control of the anthropomorphic hand and wrist. PMID:27580298

Independent development of the Reach and the Grasp in spontaneous self-touching by human infants in the first 6 months.

PubMed

Thomas, Brittany L; Karl, Jenni M; Whishaw, Ian Q

2014-01-01

The Dual Visuomotor Channel Theory proposes that visually guided reaching is a composite of two movements, a Reach that advances the hand to contact the target and a Grasp that shapes the digits for target purchase. The theory is supported by biometric analyses of adult reaching, evolutionary contrasts, and differential developmental patterns for the Reach and the Grasp in visually guided reaching in human infants. The present ethological study asked whether there is evidence for a dissociated development for the Reach and the Grasp in nonvisual hand use in very early infancy. The study documents a rich array of spontaneous self-touching behavior in infants during the first 6 months of life and subjected the Reach movements to an analysis in relation to body target, contact type, and Grasp. Video recordings were made of resting alert infants biweekly from birth to 6 months. In younger infants, self-touching targets included the head and trunk. As infants aged, targets became more caudal and included the hips, then legs, and eventually the feet. In younger infants hand contact was mainly made with the dorsum of the hand, but as infants aged, contacts included palmar contacts and eventually grasp and manipulation contacts with the body and clothes. The relative incidence of caudal contacts and palmar contacts increased concurrently and were significantly correlated throughout the period of study. Developmental increases in self-grasping contacts occurred a few weeks after the increase in caudal and palmar contacts. The behavioral and temporal pattern of these spontaneous self-touching movements suggest that the Reach, in which the hand extends to make a palmar self-contact, and the Grasp, in which the digits close and make manipulatory movements, have partially independent developmental profiles. The results additionally suggest that self-touching behavior is an important developmental phase that allows the coordination of the Reach and the Grasp prior to and concurrent with their use under visual guidance.

Application of GRASP (General Rotorcraft Aeromechanical Stability Program) to nonlinear analysis of a cantilever beam

NASA Technical Reports Server (NTRS)

Hinnant, Howard E.; Hodges, Dewey H.

1987-01-01

The General Rotorcraft Aeromechanical Stability Program (GRASP) was developed to analyse the steady-state and linearized dynamic behavior of rotorcraft in hovering and axial flight conditions. Because of the nature of problems GRASP was created to solve, the geometrically nonlinear behavior of beams is one area in which the program must perform well in order to be of any value. Numerical results obtained from GRASP are compared to both static and dynamic experimental data obtained for a cantilever beam undergoing large displacements and rotations caused by deformations. The correlation is excellent in all cases.

Effects of Exercise Modalities on Arterial Stiffness and Wave Reflection: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

PubMed Central

Ashor, Ammar W.; Lara, Jose; Siervo, Mario; Celis-Morales, Carlos; Mathers, John C.

2014-01-01

Background and Objectives Physical activity is associated with lower cardiovascular and all-cause mortality. However, the effects of different exercise modalities on arterial stiffness are currently unclear. Our objectives were to investigate the effects of exercise modalities (aerobic, resistance or combined) on pulse wave velocity (PWV) and augmentation index (AIx), and to determine whether the effects on these indices differed according to the participants' or exercise characteristics. Methods We searched the Medline, Embase and Cochrane Library databases from inception until April 2014 for randomized controlled trials lasting ≥4 weeks investigating the effects of exercise modalities on PWV and AIx in adults aged ≥18 years. Results Forty-two studies (1627 participants) were included in this analysis. Aerobic exercise improved both PWV (WMD: −0.63 m/s, 95% CI: −0.90, −0.35) and AIx (WMD:−2.63%, 95% CI: −5.25 to −0.02) significantly. Aerobic exercise training showed significantly greater reduction in brachial-ankle (WMD: −1.01 m/s, 95% CI: −1.57, −0.44) than in carotid-femoral (WMD: -0.39 m/s, 95% CI: −0.52, −0.27) PWV. Higher aerobic exercise intensity was associated with larger reductions in AIx (β: −1.55%, CI −3.09, 0.0001). In addition, aerobic exercise had a significantly larger effect in reducing PWV (WMD:−1.0 m/s, 95% CI: −1.43, −0.57) in participants with stiffer arteries (PWV ≥8 m/s). Resistance exercise had no effect on PWV and AIx. There was no significant effect of combined exercise on PWV and AIx. Conclusions We conclude that aerobic exercise improved arterial stiffness significantly and that the effect was enhanced with higher aerobic exercise intensity and in participants with greater arterial stiffness at baseline. Trial Registration PROSPERO Database registration: CRD42014009744,. PMID:25333969

Randomized Controlled Trial Comparing Exercise to Health Education for Stimulant Use Disorder: Results From the CTN-0037 STimulant Reduction Intervention Using Dosed Exercise (STRIDE) Study.

PubMed

Trivedi, Madhukar H; Greer, Tracy L; Rethorst, Chad D; Carmody, Thomas; Grannemann, Bruce D; Walker, Robrina; Warden, Diane; Shores-Wilson, Kathy; Stoutenberg, Mark; Oden, Neal; Silverstein, Meredith; Hodgkins, Candace; Love, Lee; Seamans, Cindy; Stotts, Angela; Causey, Trey; Szucs-Reed, Regina P; Rinaldi, Paul; Myrick, Hugh; Straus, Michele; Liu, David; Lindblad, Robert; Church, Timothy; Blair, Steven N; Nunes, Edward V

To evaluate exercise as a treatment for stimulant use disorders. The STimulant Reduction Intervention using Dosed Exercise (STRIDE) study was a randomized clinical trial conducted in 9 residential addiction treatment programs across the United States from July 2010 to February 2013. Of 497 adults referred to the study, 302 met all eligibility criteria, including DSM-IV criteria for stimulant abuse and/or dependence, and were randomized to either a dosed exercise intervention (Exercise) or a health education intervention (Health Education) control, both augmenting treatment as usual and conducted thrice weekly for 12 weeks. The primary outcome of percent stimulant abstinent days during study weeks 4 to 12 was estimated using a novel algorithm adjustment incorporating self-reported Timeline Followback (TLFB) stimulant use and urine drug screen (UDS) data. Mean percent of abstinent days based on TLFB was 90.8% (SD = 16.4%) for Exercise and 91.6% (SD = 14.7%) for Health Education participants. Percent of abstinent days using the eliminate contradiction (ELCON) algorithm was 75.6% (SD = 27.4%) for Exercise and 77.3% (SD = 25.1%) for Health Education. The primary intent-to-treat analysis, using a mixed model controlling for site and the ELCON algorithm, produced no treatment effect (P = .60). In post hoc analyses controlling for treatment adherence and baseline stimulant use, Exercise participants had a 4.8% higher abstinence rate (78.7%) compared to Health Education participants (73.9%) (P = .03, number needed to treat = 7.2). The primary analysis indicated no significant difference between exercise and health education. Adjustment for intervention adherence showed modestly but significantly higher percent of abstinent days in the exercise group, suggesting that exercise may improve outcomes for stimulant users who have better adherence to an exercise dose. ClinicalTrials.gov identifier: NCT01141608. © Copyright 2017 Physicians Postgraduate Press, Inc.

Design and validation of low-cost assistive glove for hand assessment and therapy during activity of daily living-focused robotic stroke therapy.

PubMed

Nathan, Dominic E; Johnson, Michelle J; McGuire, John R

2009-01-01

Hand and arm impairment is common after stroke. Robotic stroke therapy will be more effective if hand and upper-arm training is integrated to help users practice reaching and grasping tasks. This article presents the design, development, and validation of a low-cost, functional electrical stimulation grasp-assistive glove for use with task-oriented robotic stroke therapy. Our glove measures grasp aperture while a user completes simple-to-complex real-life activities, and when combined with an integrated functional electrical stimulator, it assists in hand opening and closing. A key function is a new grasp-aperture prediction model, which uses the position of the end-effectors of two planar robots to define the distance between the thumb and index finger. We validated the accuracy and repeatability of the glove and its capability to assist in grasping. Results from five nondisabled subjects indicated that the glove is accurate and repeatable for both static hand-open and -closed tasks when compared with goniometric measures and for dynamic reach-to-grasp tasks when compared with motion analysis measures. Results from five subjects with stroke showed that with the glove, they could open their hands but without it could not. We present a glove that is a low-cost solution for in vivo grasp measurement and assistance.

Different left brain regions are essential for grasping a tool compared with its subsequent use.

PubMed

Randerath, Jennifer; Goldenberg, Georg; Spijkers, Will; Li, Yong; Hermsdörfer, Joachim

2010-10-15

Tool use engages a left hemispheric network including frontal, temporal and parietal regions. Patients with left brain lesions (LBD patients) exhibit deficits when demonstrating use of a single tool (apraxia). When attempting to use a tool, some apraxic patients show errors in the preceding grasping movement. Forty-two LBD patients and 18 healthy controls grasped individual tools and demonstrated their typical use. For patients with a tool use impairment (22), lesion analysis revealed a large area of overlap in the left hemisphere, mainly in the supramarginal gyrus (SMG). For patients with erroneous grasping (12), the lesion overlay showed overlaps in the left frontal and parietal cortices, especially in the inferior frontal gyrus (IFG) and the angular gyrus (ANG). However, contrasting lesions associated with impaired grasping versus tool use impairments reveal little overlap, limited to the inferior parietal cortex. Presumably the left IFG is involved in selection processes in the context of tool use, such as choosing a functional or non-functional grasping movement depending on the task and the online information about the tool's structure and orientation. The ANG might provide this grasp related information, which is relevant for the specific action. The contribution of the SMG to tool use involves more general principals, such as integrating online and learned tool use information into the action plan for the use movement. Copyright 2010 Elsevier Inc. All rights reserved.

The Wire-Grasping Method as a New Technique for Forceps Biopsy of Biliary Strictures: A Prospective Randomized Controlled Study of Effectiveness

PubMed Central

Yamashita, Yasunobu; Ueda, Kazuki; Kawaji, Yuki; Tamura, Takashi; Itonaga, Masahiro; Yoshida, Takeichi; Maeda, Hiroki; Magari, Hirohito; Maekita, Takao; Iguchi, Mikitaka; Tamai, Hideyuki; Ichinose, Masao; Kato, Jun

2016-01-01

Background/Aims Transpapillary forceps biopsy is an effective diagnostic technique in patients with biliary stricture. This prospective study aimed to determine the usefulness of the wire-grasping method as a new technique for forceps biopsy. Methods Consecutive patients with biliary stricture or irregularities of the bile duct wall were randomly allocated to either the direct or wire-grasping method group. In the wire-grasping method, forceps in the duodenum grasps a guide-wire placed into the bile duct beforehand, and then, the forceps are pushed through the papilla without endoscopic sphincterotomy. In the direct method, forceps are directly pushed into the bile duct alongside a guide-wire. The primary endpoint was the success rate of obtaining specimens suitable for adequate pathological examination. Results In total, 32 patients were enrolled, and 28 (14 in each group) were eligible for analysis. The success rate was significantly higher using the wire-grasping method than the direct method (100% vs 50%, p=0.016). Sensitivity and accuracy for the diagnosis of cancer were comparable in patients with the successful procurement of biopsy specimens between the two methods (91% vs 83% and 93% vs 86%, respectively). Conclusions The wire-grasping method is useful for diagnosing patients with biliary stricture or irregularities of the bile duct wall. PMID:27021502

Spatiotemporal distribution of location and object effects in the electromyographic activity of upper extremity muscles during reach-to-grasp

PubMed Central

Rouse, Adam G.

2016-01-01

In reaching to grasp an object, proximal muscles that act on the shoulder and elbow classically have been viewed as transporting the hand to the intended location, while distal muscles that act on the fingers simultaneously shape the hand to grasp the object. Prior studies of electromyographic (EMG) activity in upper extremity muscles therefore have focused, by and large, either on proximal muscle activity during reaching to different locations or on distal muscle activity as the subject grasps various objects. Here, we examined the EMG activity of muscles from the shoulder to the hand, as monkeys reached and grasped in a task that dissociated location and object. We quantified the extent to which variation in the EMG activity of each muscle depended on location, on object, and on their interaction—all as a function of time. Although EMG variation depended on both location and object beginning early in the movement, an early phase of substantial location effects in muscles from proximal to distal was followed by a later phase in which object effects predominated throughout the extremity. Interaction effects remained relatively small. Our findings indicate that neural control of reach-to-grasp may occur largely in two sequential phases: the first, serving to project the entire upper extremity toward the intended location, and the second, acting predominantly to shape the entire extremity for grasping the object. PMID:27009156

Effects of β-Hydroxy-β-methylbutyrate Free Acid Ingestion and Resistance Exercise on the Acute Endocrine Response

PubMed Central

Townsend, Jeremy R.; Hoffman, Jay R.; Gonzalez, Adam M.; Jajtner, Adam R.; Boone, Carleigh H.; Robinson, Edward H.; Mangine, Gerald T.; Wells, Adam J.; Fragala, Maren S.; Fukuda, David H.; Stout, Jeffrey R.

2015-01-01

Objective. To examine the endocrine response to a bout of heavy resistance exercise following acute β-hydroxy-β-methylbutyrate free acid (HMB-FA) ingestion. Design. Twenty resistance trained men were randomized and consumed either 1 g of HMB-FA (BetaTor) or placebo (PL) 30 min prior to performing an acute heavy resistance exercise protocol. Blood was obtained before (PRE), immediately after (IP), and 30 min after exercise (30P). Circulating concentrations of testosterone, growth hormone (GH), insulin-like growth factor (IGF-1), and insulin were assayed. Data were analyzed with a repeated measures ANOVA and area under the curve (AUC) was analyzed by the trapezoidal rule. Results. The resistance exercise protocol resulted in significant elevations from PRE in testosterone (P < 0.01), GH (P < 0.01), and insulin (P = 0.05) at IP, with GH (P < 0.01) and insulin (P < 0.01) remaining elevated at 30P. A significant interaction was noted between groups in the plasma GH response at IP, which was significantly higher following HMB-FA compared to PL (P < 0.01). AUC analysis revealed an elevated GH and IGF-1 response in the HMB-FA group compared to PL. Conclusion. HMB-FA prior to resistance exercise augments the GH response to high volume resistance exercise compared to PL. These findings provide further support for the potential anabolic benefits associated with HMB supplementation. PMID:25792982

Nutritional targets to enhance exercise performance in chronic obstructive pulmonary disease.

PubMed

van de Bool, Coby; Steiner, Michael C; Schols, Annemie M W J

2012-11-01

This review presents current knowledge regarding the rationale and efficacy of nutrition as an ergogenic aid to enhance the effects of exercise and training in chronic obstructive pulmonary disease (COPD). Altered body composition and skeletal muscle dysfunction in COPD suggest that exercise capacity can be targeted via several metabolic routes. Muscle metabolic alterations in COPD include a reduced oxidative metabolism and enhanced susceptibility for oxidative stress. Muscle wasting may be associated with deficiencies of vitamin D and low branched-chain amino acid levels. Exercise training is of established benefit in COPD but clear-cut clinical trial evidence to support the performance enhancing effect of nutritional intervention is lacking. One randomized controlled trial suggested that augmentation of training with polyunsaturated fatty acids may improve exercise capacity. Conflicting results are reported on dietary creatine supplementation in patients with COPD receiving pulmonary rehabilitation and results from acute intervention studies do not directly imply long-term effects of glutamate or glutamine supplementation as an ergogenic aid in COPD. Recent data indicate that not only muscle but also visceral fat may be an important additional target for combined nutrition and exercise intervention in COPD to improve physical performance and decrease cardiometabolic risk. There is a clear need for adequately powered and controlled intervention and maintenance trials to establish the role of nutritional supplementation in the enhancement of exercise performance and training and the wider management of the systemic features of the disease.

An affordable, computerised, table-based exercise system for stroke survivors.

PubMed

King, Marcus; Hale, Leigh; Pekkari, Anna; Persson, Martin; Gregorsson, Malin; Nilsson, Mikaela

2010-07-01

Loss of hand function as a result of upper limb paresis after a stroke leads to reduced independence. Robotic-assisted therapy with virtual reality leads to improvements in motor function, but there is a need to improve the cost-benefit ratio of these therapies. This case series study investigated augmented reality computer games which provided a rewarded, goal-directed task to upper limb rehabilitation via a gravity supported reaching task. A computer game was developed to motivate chronic stroke survivors to undertake gravity supported reaching tasks performed on a table, and a focus group study investigated the application of this device for rehabilitation. From the focus group, a simple device was developed to improve the quality of the exercise and a further focus group study investigated a variety of computer games to determine motivations for undertaking rehabilitation exercises. Of the four participants in the case study, two showed improvement in ability to play the game and in arm function. Participants enjoyed playing a range of computer games and felt that the system provided a worthwhile exercise. Motivation for undertaking exercise with the system included: intellectual stimulation during game play, feedback such as game score, gaining physical benefits from the exercise, the system tolerating varying levels of disability, ability to relate to the game and ability to use the system in social groups. A low-cost device has been developed which increases the exercise of gravity supported reaching movements, provides goal-directed tasks with rewards and motivates the user to undertake extended rehabilitation.

Omega-3 fatty acid supplementation enhances stroke volume and cardiac output during dynamic exercise.

PubMed

Walser, Buddy; Stebbins, Charles L

2008-10-01

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have beneficial effects on cardiovascular function. We tested the hypotheses that dietary supplementation with DHA (2 g/day) + EPA (3 g/day) enhances increases in stroke volume (SV) and cardiac output (CO) and decreases in systemic vascular resistance (SVR) during dynamic exercise. Healthy subjects received DHA + EPA (eight men, four women) or safflower oil (six men, three women) for 6 weeks. Both groups performed 20 min of bicycle exercise (10 min each at a low and moderate work intensity) before and after DHA + EPA or safflower oil treatment. Mean arterial pressure (MAP), heart rate (HR), SV, CO, and SVR were assessed before exercise and during both workloads. HR was unaffected by DHA + EPA and MAP was reduced, but only at rest (88 +/- 5 vs. 83 +/- 4 mm Hg). DHA + EPA augmented increases in SV (14.1 +/- 6.3 vs. 32.3 +/- 8.7 ml) and CO (8.5 +/- 1.0 vs. 10.3 +/- 1.2 L/min) and tended to attenuate decreases in SVR (-7.0 +/- 0.6 vs. -10.1 +/- 1.6 mm Hg L(-1) min(-1)) during the moderate workload. Safflower oil treatment had no effects on MAP, HR, SV, CO or SVR at rest or during exercise. DHA + EPA-induced increases in SV and CO imply that dietary supplementation with these fatty acids can increase oxygen delivery during exercise, which may have beneficial clinical implications for individuals with cardiovascular disease and reduced exercise tolerance.

Redox interventions to increase exercise performance

PubMed Central

2015-01-01

Abstract Skeletal muscle continually produces reactive oxygen species (ROS) and nitric oxide (NO) derivatives. Both oxidant cascades have complex effects on muscle contraction, metabolic function and tissue perfusion. Strenuous exercise increases oxidant production by muscle, limiting performance during endurance exercise tasks. Conversely, redox interventions that modulate ROS or NO activity have the potential to improve performance. Antioxidants have long been known to buffer ROS activity and lessen oxidative perturbations during exercise. The capacity to enhance human performance varies among antioxidant categories. Vitamins, provitamins and nutriceuticals often blunt oxidative changes at the biochemical level but do not enhance performance. In contrast, reduced thiol donors have been shown to delay fatigue or increase endurance under a variety of experimental conditions. Dietary nitrate supplementation has recently emerged as a second redox strategy for increasing endurance. Purified nitrate salts and nitrate‐rich foods, notably beetroot and beetroot juice, are reported to lessen the oxygen cost of exercise, increase efficiency, and enhance performance during endurance tasks. These findings are exciting but enigmatic since nitrate per se has little bioactivity and cannot be converted to NO by mammalian cells. Overall, the available data suggest exercise endurance can be augmented by redox‐active supplements, either reduced thiol donors or dietary nitrates. These findings have clear implications for athletes seeking a competitive edge. More importantly, interventions that increase endurance may benefit individuals whose physical activity is limited by illness, ageing, or frailty. PMID:26584644

Yerba Maté (Ilex paraguariensis) Metabolic, Satiety, and Mood State Effects at Rest and during Prolonged Exercise.

PubMed

Alkhatib, Ahmad; Atcheson, Roisin

2017-08-15

Yerba Maté (YM), has become a popular herb ingested for enhancing metabolic health and weight-loss outcomes. No studies have tested the combined metabolic, satiety, and psychomotor effects of YM during exercise. We tested whether YM ingestion affects fatty acid oxidation (FAO), profile of mood state score (POMS), and subjective appetite scale (VAS), during prolonged moderate exercise. Twelve healthy active females were randomized to ingest either 2 g of YM or placebo (PLC) in a repeated-measures design. Participants rested for 120 min before performing a 30-min cycling exercise corresponding to individuals' crossover point intensity (COP). FAO, determined using indirect calorimetry, was significantly higher during the 30-min exercise in YM vs. PLC (0.21 ± 0.07 vs. 0.17 ± 0.06 g/min, p < 0.05). VAS scores for hunger, prospective eating, and desire to eat were all reduced ( p < 0.05). Whereas, POMS measures of focus, energy, and concentration were all increased ( p < 0.05). There was no significant time-effect for any of the measured variables, nor was there any interaction effects between YM treatment and time. Combining YM intake with prolonged exercise at targeted "fat-loss"' intensities augments FAO and improves measures of satiety and mood state. Such positive combined metabolic, satiety, and psychomotor effects may provide an important role for designing future fat and weight-loss lifestyle interventions.

Endurance Exercise in Hypoxia, Hyperoxia and Normoxia: Mitochondrial and Global Adaptations.

PubMed

Przyklenk, Axel; Gutmann, Boris; Schiffer, Thorsten; Hollmann, Wildor; Strueder, Heiko K; Bloch, Wilhelm; Mierau, Andreas; Gehlert, Sebastian

2017-07-01

We hypothesized short-term endurance exercise (EN) in hypoxia (HY) to exert decreased mitochondrial adaptation, peak oxygen consumption (VO 2peak ) and peak power output (PPO) compared to EN in normoxia (NOR) and hyperoxia (PER). 11 male subjects performed repeated unipedal cycling EN in HY, PER, and NOR over 4 weeks in a cross-over design. VO 2peak , PPO, rate of perceived exertion (RPE) and blood lactate (Bla) were determined pre- and post-intervention to assess physiological demands and adaptation. Skeletal muscle biopsies were collected to determine molecular mitochondrial signaling and adaptation. Despite reduced exercise intensity (P<0.05), increased Bla and RPE levels in HY revealed higher metabolic load compared to PER (P<0.05) and NOR (n.s.). PPO increased in all groups (P<0.05) while VO 2peak and mitochondrial signaling were unchanged (P>0.05). Electron transport chain complexes tended to increase in all groups with the highest increase in HY (n.s.). EN-induced mitochondrial adaptability and exercise capacity neither decreased significantly in HY nor increased in PER compared to NOR. Despite decreased exercise intensity, short term EN under HY may not necessarily impair mitochondrial adaptation and exercise capacity while PER does not augment adaptation. HY might strengthen adaptive responses under circumstances when absolute training intensity has to be reduced. © Georg Thieme Verlag KG Stuttgart · New York.

Mixed-reality exercise effects on participation of individuals with spinal cord injuries and developmental disabilities: a pilot study.

PubMed

Heyn, Patricia C; Baumgardner, Chad A; McLachlan, Leslie; Bodine, Cathy

2014-01-01

The purpose of this pilot study was to investigate the effectiveness of a mixed-reality (MR) exercise environment on engagement and enjoyment levels of individuals with spinal cord injury (SCI) and intellectual and developmental disabilities (IDD). Six people participated in this cross-sectional, observational pilot study involving one MR exercise trial. The augmented reality environment was based on a first-person perspective video of a scenic biking/walking trail in Colorado. Males and females (mean age, 43.3 ± 13.7 years) were recruited from a research database for their participation in previous clinical studies. Of the 6 participants, 2 had SCI, 2 had IDD, and 2 were without disability. The primary outcome measurement of this pilot study was the self-reported engagement and enjoyment level of each participant after the exercise trial. All participants reported increased levels of engagement, enjoyment, and immersion involving the MR exercise environment as well as positive feedback recommending this type of exercise approach to peers with similar disabilities. All the participants reported higher than normal levels of enjoyment and 66.7% reported higher than normal levels of being on a real trail. Participants' feedback suggested that the MR environment could be entertaining, motivating, and engaging for users with disabilities, resulting in a foundation for further development of this technology for use in individuals with cognitive and physical disabilities.

Low-level carbon monoxide exposure and work capacity at 1600 meters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiser, P.C.; Cropp, G.J.A.; Morrill, C.G.

At sea level, low-level carbon monoxide (CO) exposure impairs exercise performance. To determine if altitude residence at 1600 m augments this CO effect, two studies of graded treadmill work capacity were done. The Initial Study investigated nine, non-smoking male subjects breathing either filtered air (FA) or 28 ppm CO in filtered air. End-exercise carboxyhemoglobin (HbCO) levels averaged 0.9 %HbCO breathing FA and 4.7 %HbCO breathing CO. Total work performance and aerobic work capacity were reduced. Work heart rate was elevated, and post-exercise left ventricular ejection time breathing CO did not shorten to the same degree as with FA exposure. COmore » exposure resulted in a lower anaerobic threshold, and a greater minute ventilation occurred at work rates heavier than the anaerobic threshold due to an increased blood lactate level. The Dose-Response Study exposed twelve subjects to FA or CO such that the end-exercise HbCO levels were 0.7, 3.5, 5.4 and 8.7 %HbCO. Exercise performance and aerobic work capacity were impaired in proportion to the CO exposure. In both studies, maximal cardio-pulmonary responses were not different, but submaximal exercise changes were elevated breathing CO. Thus, in healthy young men residing near 1600 m, an increase in low-level CO exposure produced a linear decrement in maximal aerobic performance similar to that reported at sea level.« less

Respiratory Motion-Resolved Compressed Sensing Reconstruction of Free-Breathing Radial Acquisition for Dynamic Liver MRI

PubMed Central

Chandarana, Hersh; Feng, Li; Ream, Justin; Wang, Annie; Babb, James S; Block, Kai Tobias; Sodickson, Daniel K; Otazo, Ricardo

2015-01-01

Purpose Demonstrate feasibility of free-breathing radial acquisition with respiratory motion-resolved compressed sensing (CS) reconstruction (XD-GRASP) for multiphase dynamic Gd-EOB-DTPA enhanced liver imaging, and compare image quality to CS reconstruction with respiratory motion-averaging (GRASP) and prior conventional breath-held Cartesian-sampled datasets (BH-VIBE) in same patients. Subjects and Methods In this HIPAA-compliant prospective study, 16 subjects underwent free-breathing continuous radial acquisition during Gd-EOB-DTPA injection, and had prior BH-VIBE exam available. Acquired data were reconstructed using motion-averaging GRASP approach, in which consecutive 84-spokes were grouped in each contrast-enhanced phase for a temporal resolution of ~14 seconds. Additionally, respiratory motion-resolved reconstruction was performed from the same k-space data, by sorting each contrast-enhanced phase into multiple respiratory motion states using compressed sensing algorithm named XD-GRASP, which exploits sparsity along both the contrast-enhancement and respiratory-state dimensions. Contrast-enhanced dynamic multi-phase XD-GRASP, GRASP, and BH-VIBE images were anonymized, pooled together in a random order and presented to two board-certified radiologists for independent evaluation of image quality, with higher score indicating more optimal exam. Results XD-GRASP reconstructions had significantly (all p<0.05) higher overall image quality scores compared to GRASP for early arterial (Reader 1: 4.3 ± 0.6 vs. 3.31 ± 0.6 ; Reader 2: 3.81 ± 0.8 vs. 3.38 ± 0.9) and late arterial (Reader 1: 4.5 ± 0.6 vs. 3.63 ± 0.6; Reader 2: 3.56 ± 0.5 vs. 2.88 ± 0.7) phases of enhancement for both readers. XD-GRASP also had higher overall image quality score in portal venous phase which was significant for Reader 1 (4.44 ± 0.5 vs. 3.75 ± 0.8; p=0.002). In addition, XD-GRASP had higher overall image quality score compared to BH-VIBE for early (Reader 1: 4.3±0.6 vs. 3.88±0.6; Reader 2: 3.81±0.8 vs. 3.50±1.0) and late (Reader 1: 4.5±0.6 vs. 3.44±0.6; Reader 2: 3.56±0.5 vs. 2.94±0.9) arterial phases. Conclusion Free-breathing motion-resolved XD-GRASP reconstructions provide diagnostic high-quality multiphase images in patients undergoing Gd-EOB-DTPA-enhanced liver exam. PMID:26146869

Bone indicators of grasping hands in lizards

PubMed Central

2016-01-01

Grasping is one of a few adaptive mechanisms that, in conjunction with clinging, hooking, arm swinging, adhering, and flying, allowed for incursion into the arboreal eco-space. Little research has been done that addresses grasping as an enhanced manual ability in non-mammalian tetrapods, with the exception of studies comparing the anatomy of muscle and tendon structure. Previous studies showed that grasping abilities allow exploitation for narrow branch habitats and that this adaptation has clear osteological consequences. The objective of this work is to ascertain the existence of morphometric descriptors in the hand skeleton of lizards related to grasping functionality. A morphological matrix was constructed using 51 morphometric variables in 278 specimens, from 24 genera and 13 families of Squamata. To reduce the dimensions of the dataset and to organize the original variables into a simpler system, three PCAs (Principal Component Analyses) were performed using the subsets of (1) carpal variables, (2) metacarpal variables, and (3) phalanges variables. The variables that demonstrated the most significant contributions to the construction of the PCA synthetic variables were then used in subsequent analyses. To explore which morphological variables better explain the variations in the functional setting, we ran Generalized Linear Models for the three different sets. This method allows us to model the morphology that enables a particular functional trait. Grasping was considered the only response variable, taking the value of 0 or 1, while the original variables retained by the PCAs were considered predictor variables. Our analyses yielded six variables associated with grasping abilities: two belong to the carpal bones, two belong to the metacarpals and two belong to the phalanges. Grasping in lizards can be performed with hands exhibiting at least two different independently originated combinations of bones. The first is a combination of a highly elongated centrale bone, reduced palmar sesamoid, divergence angles above 90°, and slender metacarpal V and phalanges, such as exhibited by Anolis sp. and Tropidurus sp. The second includes an elongated centrale bone, lack of a palmar sesamoid, divergence angles above 90°, and narrow metacarpal V and phalanges, as exhibited by geckos. Our data suggest that the morphological distinction between graspers and non-graspers is demonstrating the existence of ranges along the morphological continuum within which a new ability is generated. Our results support the hypothesis of the nested origin of grasping abilities within arboreality. Thus, the manifestation of grasping abilities as a response to locomotive selective pressure in the context of narrow-branch eco-spaces could also enable other grasping-dependent biological roles, such as prey handling. PMID:27168987

Using kinematic reduction for studying grasping postures. An application to power and precision grasp of cylinders.

PubMed

Jarque-Bou, N; Gracia-Ibáñez, V; Sancho-Bru, J L; Vergara, M; Pérez-González, A; Andrés, F J

2016-09-01

The kinematic analysis of human grasping is challenging because of the high number of degrees of freedom involved. The use of principal component and factorial analyses is proposed in the present study to reduce the hand kinematics dimensionality in the analysis of posture for ergonomic purposes, allowing for a comprehensive study without losing accuracy while also enabling velocity and acceleration analyses to be performed. A laboratory study was designed to analyse the effect of weight and diameter in the grasping posture for cylinders. This study measured the hand posture from six subjects when transporting cylinders of different weights and diameters with precision and power grasps. The hand posture was measured using a Vicon(®) motion-tracking system, and the principal component analysis was applied to reduce the kinematics dimensionality. Different ANOVAs were performed on the reduced kinematic variables to check the effect of weight and diameter of the cylinders, as well as that of the subject. The results show that the original twenty-three degrees of freedom of the hand were reduced to five, which were identified as digit arching, closeness, palmar arching, finger adduction and thumb opposition. Both cylinder diameter and weight significantly affected the precision grasping posture: diameter affects closeness, palmar arching and opposition, while weight affects digit arching, palmar arching and closeness. The power-grasping posture was mainly affected by the cylinder diameter, through digit arching, closeness and opposition. The grasping posture was largely affected by the subject factor and this effect couldn't be attributed only to hand size. In conclusion, this kinematic reduction allowed identifying the effect of the diameter and weight of the cylinders in a comprehensive way, being diameter more important than weight. Copyright © 2016 Elsevier Ltd. All rights reserved.

On the evolution of handedness: evidence for feeding biases.

PubMed

Flindall, Jason W; Gonzalez, Claudia L R

2013-01-01

Many theories have been put forward to explain the origins of right-handedness in humans. Here we present evidence that this preference may stem in part from a right hand advantage in grasping for feeding. Thirteen participants were asked to reach-to-grasp food items of 3 different sizes: SMALL (Cheerios®), MEDIUM (Froot Loops®), and LARGE (Oatmeal Squares®). Participants used both their right- and left-hands in separate blocks (50 trials each, starting order counterbalanced) to grasp the items. After each grasp, participants either a) ate the food item, or b) placed it inside a bib worn beneath his/her chin (25 trials each, blocked design, counterbalanced). The conditions were designed such that the outward and inward movement trajectories were similar, differing only in the final step of placing it in the mouth or bib. Participants wore Plato liquid crystal goggles that blocked vision between trials. All trials were conducted in closed-loop with 5000 ms of vision. Hand kinematics were recorded by an Optotrak Certus, which tracked the position of three infrared diodes attached separately to the index finger, thumb, and wrist. We found a task (EAT/PLACE) by hand (LEFT/RIGHT) interaction on maximum grip aperture (MGA; the maximum distance between the index finger and thumb achieved during grasp pre-shaping). MGAs were smaller during right-handed movements, but only when grasping with intent to eat. Follow-up tests show that the RIGHT-HAND/EAT MGA was significantly smaller than all other hand/task conditions. Because smaller grip apertures are typically associated with greater precision, our results demonstrate a right-hand advantage for the grasp-to-eat movement. From an evolutionary perspective, early humans may have preferred the hand that could grasp food with more precision, thereby maximizing the likelihood of retrieval, consumption, and consequently, survival.

Effect of pencil grasp on the speed and legibility of handwriting after a 10-minute copy task in Grade 4 children.

PubMed

Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl; Chau, Tom

2012-06-01

To investigate the impact of common pencil grasp patterns on the speed and legibility of handwriting after a 10-minute copy task, intended to induce muscle fatigue, in typically developing children and in those non-proficient in handwriting. A total of 120 Grade 4 students completed a standardised handwriting assessment before and after a 10-minute copy task. The students indicated the perceived difficulty of the handwriting task at baseline and after 10 minutes. The students also completed a self-report questionnaire regarding their handwriting proficiency upon completion. The majority of the students rated higher effort after the 10-minute copy task than at baseline (rank sum: P = 0.00001). The effort ratings were similar for the different grasp patterns (multiple linear regression: F = 0.37, P = 0.895). For both typically developing children and those with handwriting issues, the legibility of the writing samples decreased after the 10-minute copy task but the speed of writing increased. CONCLUSIONS AND SIGNIFICANCE OF THE STUDY: The quality of the handwriting decreased after the 10-minute copy task; however, there was no difference in the quality or speed scores among the different pencil grasps before and after the copy task. The dynamic tripod pencil grasp did not offer any advantage over the lateral tripod or the dynamic or lateral quadrupod pencil grasps in terms of quality of handwriting after a 10-minute copy task. These four pencil grasp patterns performed equivalently. Our findings question the practice of having students adopt the dynamic tripod pencil grasp. © 2012 The Authors Australian Occupational Therapy Journal © 2012 Occupational Therapy Australia.

How Weight Affects the Perceived Spacing between the Thumb and Fingers during Grasping

PubMed Central

Butler, Annie A.; Héroux, Martin E.; Gandevia, Simon C.

2015-01-01

We know much about mechanisms determining the perceived size and weight of lifted objects, but little about how these properties of size and weight affect the body representation (e.g. grasp aperture of the hand). Without vision, subjects (n = 16) estimated spacing between fingers and thumb (perceived grasp aperture) while lifting canisters of the same width (6.6cm) but varied weights (300, 600, 900, and 1200 g). Lifts were performed by movement of either the wrist, elbow or shoulder to examine whether lifting with different muscle groups affects the judgement of grasp aperture. Results for perceived grasp aperture were compared with changes in perceived weight of objects of different sizes (5.2, 6.6, and 10 cm) but the same weight (600 g). When canisters of the same width but different weights were lifted, perceived grasp aperture decreased 4.8% [2.2 ‒ 7.4] (mean [95% CI]; P < 0.001) from the lightest to the heaviest canister, no matter how they were lifted. For objects of the same weight but different widths, perceived weight decreased 42.3% [38.2 ‒ 46.4] from narrowest to widest (P < 0.001), as expected from the size-weight illusion. Thus, despite a highly distorted perception of the weight of objects based on their size, we conclude that proprioceptive afferents maintain a reasonably stable perception of the aperture of the grasping hand over a wide range of object weights. Given the small magnitude of this ‘weight-grasp aperture’ illusion, we propose the brain has access to a relatively stable ‘perceptual ruler’ to aid the manipulation of different objects. PMID:25996760

Aerobic Exercise Training and Arterial Changes in African Americans versus Caucasians.

PubMed

Ranadive, Sushant M; Yan, Huimin; Lane, Abbi D; Kappus, Rebecca M; Cook, Marc D; Sun, Peng; Harvey, Idethia; Ploutz-Synder, Robert; Woods, Jeffrey A; Wilund, Kenneth R; Fernhall, B O

2016-01-01

African Americans (AA) have increased carotid artery intima-media thickness and decreased vascular function compared with their Caucasian (CA) peers. Aerobic exercise prevents and potentially reverses arterial dysfunction. The purpose of this study was to examine the effect of 8 wk of moderate- to high-intensity aerobic training in young healthy sedentary AA and CA men and women. Sixty-four healthy volunteers (men, 28; women, 36) with mean age 24 yr underwent measures of arterial structure, function, and blood pressure (BP) variables at baseline, after the 4-wk control period, and 8 wk after training. There was a significant increase in VO2peak among both groups after exercise training. Brachial systolic BP decreased significantly after the control period in both groups but not after exercise training. Carotid pulse pressure decreased significantly in both groups after exercise training as compared with that in baseline. There was no change in any of the other BP variables. AA had higher intima-media thickness at baseline and after the control period but it significantly decreased after exercise training compared with that of CA. AA had significantly lower baseline forearm blood flow and reactive hyperemia compared with those of CA, but exercise training had no effect on these variables. There was no significant difference in arterial stiffness (central pulse wave velocity) and wave-reflection (augmentation index) between the two groups at any time point. This is the first study to show that 8 wk of aerobic exercise training causes significant improvement in the arterial structure in young, healthy AA, making it comparable with the CA and with minimal effects on BP variables.

Community-based group aquatic programme for individuals with multiple sclerosis: a pilot study.

PubMed

Salem, Yasser; Scott, Anne Hiller; Karpatkin, Herbert; Concert, George; Haller, Leah; Kaminsky, Eva; Weisbrot, Rivky; Spatz, Eugene

2011-01-01

The purpose of this study was to determine the feasibility of providing a community-based aquatic exercise programme and to examine the effects of a group aquatic exercise programme in individuals with multiple sclerosis. This study illustrates the implementation of a multidisciplinary community-based programme in a university community wellness centre coordinated with a local advocacy group. Eleven subjects with multiple sclerosis participated in a 5-week community-based aquatic exercise programme. Aquatic exercises were held twice weekly for 60 minutes and included aerobic exercises, strength training, flexibility exercises, balance training and walking activities. The 10-Metre Walk test, the Berg Balance Scale (BBS), the 'Timed Up and Go' (TUG) test, grip strength and the Modified Fatigue Impact Scale were used to assess motor function. Analysis of the scores demonstrated improved gait speed, BBS, TUG test and grip strength. The average attendance of the training sessions was good (88%), and no incidence of injuries, no incidence of falls and no adverse effects related to the exercise programme were reported. All participants reported that they enjoyed the programme, and they had improved after the training. A community-based aquatic exercise programme is feasible and resulted in improvement in motor functions of individuals with multiple sclerosis. These findings indicate that an aquatic training programme is appropriate and beneficial for individuals with multiple sclerosis and should be considered to augment the rehabilitation of those individuals. This programme may provide a viable model for a community-based wellness programme for people with disability including individuals with multiple sclerosis.

Neuromuscular electrical stimulation via the peroneal nerve is superior to graduated compression socks in reducing perceived muscle soreness following intense intermittent endurance exercise.

PubMed

Ferguson, Richard A; Dodd, Matthew J; Paley, Victoria R

2014-10-01

A novel technique of neuromuscular electrical stimulation (NMES) via the peroneal nerve has been shown to augment limb blood flow which could enhance recovery following exercise. The present study examined the effects of NMES, compared to graduated compression socks on muscle soreness, strength, and markers of muscle damage and inflammation following intense intermittent exercise. Twenty-one (age 21 ± 1 years, height 179 ± 7 cm, body mass 76 ± 9 kg,) healthy males performed a 90-min intermittent shuttle running test on three occasions. Following exercise, the following interventions were applied: passive recovery (CON), graduated compression socks (GCS) or NMES. Perceived muscle soreness (PMS) and muscle strength (isometric maximal voluntary contraction of knee extensors and flexors) were measured and a venous blood sample taken pre-exercise and 0, 1, 24, 48 and 72 h following exercise for measurement of creatine kinase (CK) and Lactate dehydrogenase (LDH) activity and IL-6 and CRP concentrations. PMS increased in all conditions immediately, 1 and 24 h post-exercise. At 24 h PMS was lower in NMES compared to GCS and CON (2.0 ± 1.6, 3.2 ± 2.1, 4.6 ± 2.0, respectively). At 48 h PMS was lower in NMES compared to CON (1.3 ± 1.5 and 3.1 ± 1.8, respectively). There were no differences between treatments for muscle strength, CK and LDH activity, IL-6 and CRP concentrations. The novel NMES technique is superior to GCS in reducing PMS following intense intermittent endurance exercise.

Effect of Sacubitril/Valsartan on Exercise-Induced Lipid Metabolism in Patients With Obesity and Hypertension

PubMed Central

Engeli, Stefan; Stinkens, Rudi; Heise, Tim; May, Marcus; Goossens, Gijs H.; Blaak, Ellen E.; Havekes, Bas; Jax, Thomas; Albrecht, Diego; Pal, Parasar; Tegtbur, Uwe; Haufe, Sven; Langenickel, Thomas H.

2018-01-01

Sacubitril/valsartan (LCZ696), a novel angiotensin receptor-neprilysin inhibitor, was recently approved for the treatment of heart failure with reduced ejection fraction. Neprilysin degrades several peptides that modulate lipid metabolism, including natriuretic peptides. In this study, we investigated the effects of 8 weeks’ treatment with sacubitril/valsartan on whole-body and adipose tissue lipolysis and lipid oxidation during defined physical exercise compared with the metabolically neutral comparator amlodipine. This was a multicenter, randomized, double-blind, active-controlled, parallel-group study enrolling subjects with abdominal obesity and moderate hypertension (mean sitting systolic blood pressure ≥130–180 mm Hg). Lipolysis during rest and exercise was assessed by microdialysis and [1,1,2,3,3-2H]-glycerol tracer kinetics. Energy expenditure and substrate oxidation were measured simultaneously using indirect calorimetry. Plasma nonesterified fatty acids, glycerol, insulin, glucose, adrenaline and noradrenaline concentrations, blood pressure, and heart rate were also determined. Exercise elevated plasma glycerol, free fatty acids, and interstitial glycerol concentrations and increased the rate of glycerol appearance. However, exercise-induced stimulation of lipolysis was not augmented on sacubitril/valsartan treatment compared with amlodipine treatment. Furthermore, sacubitril/valsartan did not alter energy expenditure and substrate oxidation during exercise compared with amlodipine treatment. In conclusion, sacubitril/valsartan treatment for 8 weeks did not elicit clinically relevant changes in exercise-induced lipolysis or substrate oxidation in obese patients with hypertension, implying that its beneficial cardiovascular effects cannot be explained by changes in lipid metabolism during exercise. Clinical Trial Registration— URL: https://www.clinicaltrials.gov. Unique identifier: NCT01631864. PMID:29180454

Effect of Sacubitril/Valsartan on Exercise-Induced Lipid Metabolism in Patients With Obesity and Hypertension.

PubMed

Engeli, Stefan; Stinkens, Rudi; Heise, Tim; May, Marcus; Goossens, Gijs H; Blaak, Ellen E; Havekes, Bas; Jax, Thomas; Albrecht, Diego; Pal, Parasar; Tegtbur, Uwe; Haufe, Sven; Langenickel, Thomas H; Jordan, Jens

2018-01-01

Sacubitril/valsartan (LCZ696), a novel angiotensin receptor-neprilysin inhibitor, was recently approved for the treatment of heart failure with reduced ejection fraction. Neprilysin degrades several peptides that modulate lipid metabolism, including natriuretic peptides. In this study, we investigated the effects of 8 weeks' treatment with sacubitril/valsartan on whole-body and adipose tissue lipolysis and lipid oxidation during defined physical exercise compared with the metabolically neutral comparator amlodipine. This was a multicenter, randomized, double-blind, active-controlled, parallel-group study enrolling subjects with abdominal obesity and moderate hypertension (mean sitting systolic blood pressure ≥130-180 mm Hg). Lipolysis during rest and exercise was assessed by microdialysis and [1,1,2,3,3- 2 H]-glycerol tracer kinetics. Energy expenditure and substrate oxidation were measured simultaneously using indirect calorimetry. Plasma nonesterified fatty acids, glycerol, insulin, glucose, adrenaline and noradrenaline concentrations, blood pressure, and heart rate were also determined. Exercise elevated plasma glycerol, free fatty acids, and interstitial glycerol concentrations and increased the rate of glycerol appearance. However, exercise-induced stimulation of lipolysis was not augmented on sacubitril/valsartan treatment compared with amlodipine treatment. Furthermore, sacubitril/valsartan did not alter energy expenditure and substrate oxidation during exercise compared with amlodipine treatment. In conclusion, sacubitril/valsartan treatment for 8 weeks did not elicit clinically relevant changes in exercise-induced lipolysis or substrate oxidation in obese patients with hypertension, implying that its beneficial cardiovascular effects cannot be explained by changes in lipid metabolism during exercise. URL: https://www.clinicaltrials.gov. Unique identifier: NCT01631864. © 2017 The Authors.

Mirror neurons encode the subjective value of an observed action

PubMed Central

Caggiano, Vittorio; Fogassi, Leonardo; Rizzolatti, Giacomo; Casile, Antonino; Giese, Martin A.; Thier, Peter

2012-01-01

Objects grasped by an agent have a value not only for the acting agent, but also for an individual observing the grasping act. The value that the observer attributes to the object that is grasped can be pivotal for selecting a possible behavioral response. Mirror neurons in area F5 of the monkey premotor cortex have been suggested to play a crucial role in the understanding of action goals. However, it has not been addressed if these neurons are also involved in representing the value of the grasped object. Here we report that observation-related neuronal responses of F5 mirror neurons are indeed modulated by the value that the monkey associates with the grasped object. These findings suggest that during action observation F5 mirror neurons have access to key information needed to shape the behavioral responses of the observer. PMID:22753471

Design of precise assembly equipment of large aperture optics

NASA Astrophysics Data System (ADS)

Pei, Guoqing; Xu, Xu; Xiong, Zhao; Yan, Han; Qin, Tinghai; Zhou, Hai; Yuan, Xiaodong

2017-05-01

High-energy solid-state laser is an important way to achieve laser fusion research. Laser fusion facility includes thousands of various types of large aperture optics. These large aperture optics should be assembled with high precision and high efficiency. Currently, however, the assembly of large aperture optics is by man's hand which is in low level of efficiency and labor-intensive. Here, according to the characteristics of the assembly of large aperture optics, we designed three kinds of grasping devices. Using Finite Element Method, we simulated the impact of the grasping device on the PV value and the RMS value of the large aperture optics. The structural strength of the grasping device's key part was analyzed. An experiment was performed to illustrate the reliability and precision of the grasping device. We anticipate that the grasping device would complete the assembly of large aperture optics precisely and efficiently.

Manipulation of Unknown Objects to Improve the Grasp Quality Using Tactile Information.

PubMed

Montaño, Andrés; Suárez, Raúl

2018-05-03

This work presents a novel and simple approach in the area of manipulation of unknown objects considering both geometric and mechanical constraints of the robotic hand. Starting with an initial blind grasp, our method improves the grasp quality through manipulation considering the three common goals of the manipulation process: improving the hand configuration, the grasp quality and the object positioning, and, at the same time, prevents the object from falling. Tactile feedback is used to obtain local information of the contacts between the fingertips and the object, and no additional exteroceptive feedback sources are considered in the approach. The main novelty of this work lies in the fact that the grasp optimization is performed on-line as a reactive procedure using the tactile and kinematic information obtained during the manipulation. Experimental results are shown to illustrate the efficiency of the approach.

Control of a Glove-Based Grasp Assist Device

NASA Technical Reports Server (NTRS)

Bergelin, Bryan J (Inventor); Ihrke, Chris A. (Inventor); Davis, Donald R. (Inventor); Linn, Douglas Martin (Inventor); Sanders, Adam M (Inventor); Askew, R. Scott (Inventor); Laske, Evan (Inventor); Ensley, Kody (Inventor)

2015-01-01

A grasp assist system includes a glove and sleeve. The glove includes a digit, i.e., a finger or thumb, and a force sensor. The sensor measures a grasping force applied to an object by an operator wearing the glove. The glove contains a tendon connected at a first end to the digit. The sleeve has an actuator assembly connected to a second end of the tendon and a controller in communication with the sensor. The controller includes a configuration module having selectable operating modes and a processor that calculates a tensile force to apply to the tendon for each of the selectable operating modes to assist the grasping force in a manner that differs for each of the operating modes. A method includes measuring the grasping force, selecting the mode, calculating the tensile force, and applying the tensile force to the tendon using the actuator assembly.

Food choice, appetite and physical activity.

PubMed

Bellisle, F

1999-09-01

Food choices and diet composition have been studied less often than energy intake in subjects with varying levels of physical activity. The reported effects of exercise on food choices are not fully consistent, especially on the short term. Type of exercise, intensity, duration can affect the results as well as subjects' characteristics (gender, age, previous training and fitness). A crucial role could also be played by psychological (chronic dieting, attitudes toward health and food, long-established food habits and preferences) and social (traditions, food availability, appropriate times and places) factors. In short-term intervention studies, where a meal is ingested a few minutes following a bout of exercise of varying duration and intensity, an increase in CHO intake is most often reported, while increased protein intake is an occasional observation. In long-term (several weeks) training interventions, intake is assessed from dietary records. Again CHO intake is augmented in exercised subjects as compared to controls, while that of saturated fats and cholesterol may also be affected. Epidemiological studies (without dietary or exercise intervention) often report that habitually active persons eat more and ingest more fruits and vegetables than less active peers. It is not known to what extent such food choices are driven by biological needs (e.g. replacement of glycogen) or elicited by social and psychological factors.

Carbon monoxide and lethal arrhythmias

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farber, J.P.; Schwartz, P.J.; Vanoli, E.

1990-12-01

The effect of acute exposure to carbon monoxide on ventricular arrhythmias was studied in a previously described chronically maintained animal model of sudden cardiac death. In 60 percent of dogs with a healed anterior myocardial infarction, the combination of mild exercise and acute myocardial ischemia induces ventricular fibrillation. The events in this model are highly reproducible, thus allowing study by internal control analysis. Dogs that develop ventricular fibrillation during the test of exercise and acute myocardial ischemia are considered at high risk for sudden death and are defined as 'susceptible'; dogs that survive the test without a fatal arrhythmia aremore » considered at low risk for sudden death and are defined as 'resistant.' In the current study, the effects of carboxyhemoglobin levels ranging from 5 to 15 percent were tested in resistant and susceptible dogs. A trend toward higher heart rates was observed at all levels of carboxyhemoglobin, although significant differences were observed only with 15 percent carboxyhemoglobin. This trend was observed at rest and during exercise in both resistant and susceptible dogs. In resistant animals, in which acute myocardial ischemia is typically associated with bradycardia even under the control condition, this reflex response occurred earlier and was augmented after exposure to carbon monoxide. This effect may depend on the increased hypoxic challenge caused by carbon monoxide, and thus on an augmentation of the neural reflex activation or a sensitization of the sinus node to acetylcholine induced by hypoxia. In both resistant and susceptible dogs, carbon monoxide exposure induced a worsening of ventricular arrhythmias in a minority of cases. This worsening was not reproducible in subsequent trials. These data indicate that acute exposure to carbon monoxide is seldom arrhythmogenic in dogs that have survived myocardial infarction. (Abstract Truncated)« less

High dietary phosphate intake induces hypertension and augments exercise pressor reflex function in rats.

PubMed

Mizuno, Masaki; Mitchell, Jere H; Crawford, Scott; Huang, Chou-Long; Maalouf, Naim; Hu, Ming-Chang; Moe, Orson W; Smith, Scott A; Vongpatanasin, Wanpen

2016-07-01

An increasing number of studies have linked high dietary phosphate (Pi) intake to hypertension. It is well established that the rise in sympathetic nerve activity (SNA) and blood pressure (BP) during physical exertion is exaggerated in many forms of hypertension, which are primarily mediated by an overactive skeletal muscle exercise pressor reflex (EPR). However, it remains unknown whether high dietary Pi intake potentiates the EPR-mediated SNA and BP response to exercise. Accordingly, we measured renal SNA (RSNA) and mean BP (MBP) in normotensive Sprague-Dawley rats fed a normal Pi diet (0.6%, n = 13) or high Pi diet (1.2%, n = 13) for 3 mo. As previously reported, we found that resting BP was significantly increased by 1.2% Pi diet in both conscious and anesthetized animals. Activation of the EPR by electrically induced hindlimb contraction triggered greater increases in ΔRSNA and ΔMBP in the 1.2% compared with 0.6% Pi group (126 ± 25 vs. 42 ± 9%; 44 ± 5 vs. 14 ± 2 mmHg, respectively, P < 0.01). Activation of the muscle mechanoreflex, a component of the EPR, by passively stretching hindlimb muscle also evoked greater increases in ΔRSNA and ΔMBP in the 1.2% compared with 0.6% Pi group (109 ± 27 vs. 24 ± 7%, 38 ± 7 vs. 8 ± 2 mmHg, respectively, P < 0.01). A similar response was produced by hindlimb intra-arterial capsaicin administration to stimulate the metaboreflex arm of the EPR. Thus, our data demonstrate a novel action of dietary Pi loading in augmenting EPR function through overactivation of both the muscle mechanoreflex and metaboreflex. Copyright © 2016 the American Physiological Society.

IL-1β and BDNF are associated with improvement in hypersomnia but not insomnia following exercise in major depressive disorder

PubMed Central

Rethorst, C D; Greer, T L; Toups, M S P; Bernstein, I; Carmody, T J; Trivedi, M H

2015-01-01

Given the role of sleep in the development and treatment of major depressive disorder (MDD), it is becoming increasingly clear that elucidation of the biological mechanisms underlying sleep disturbances in MDD is crucial to improve treatment outcomes. Sleep disturbances are varied and can present as insomnia and/or hypersomnia. Though research has examined the biological underpinnings of insomnia in MDD, little is known about the role of biomarkers in hypersomnia associated with MDD. This paper examines biomarkers associated with changes in hypersomnia and insomnia and as predictors of improvements in sleep quality following exercise augmentation in persons with MDD. Subjects with non-remitted MDD were randomized to augmentation with one of two doses of aerobic exercise: 16 kilocalories per kilogram of body weight per week (KKW) or 4 KKW for 12 weeks. The four sleep-related items on the clinician-rated Inventory of Depressive Symptomatology (sleep onset insomnia, mid-nocturnal insomnia, early morning insomnia and hypersomnia) assessed self-reported sleep quality. Inflammatory cytokines (tumor necrosis factor-alpha, interleukin (IL)-1β, IL-6) and brain-derived neurotrophic factor (BDNF) were assessed in blood samples collected before and following the 12-week intervention. Reduction in hypersomnia was correlated with reductions in BDNF (ρ=0.26, P=0.029) and IL-1β (ρ=0.37, P=0.002). Changes in these biomarkers were not associated with changes in insomnia; however, lower baseline levels of IL-1β were predictive of greater improvements in insomnia (F=3.87, P=0.050). In conclusion, improvement in hypersomnia is related to reductions in inflammatory markers and BDNF in persons with non-remitted MDD. Distinct biological mechanisms may explain reductions in insomnia. PMID:26241349

Role of protein and amino acids in promoting lean mass accretion with resistance exercise and attenuating lean mass loss during energy deficit in humans.

PubMed

Churchward-Venne, Tyler A; Murphy, Caoileann H; Longland, Thomas M; Phillips, Stuart M

2013-08-01

Amino acids are major nutrient regulators of muscle protein turnover. After protein ingestion, hyperaminoacidemia stimulates increased rates of skeletal muscle protein synthesis, suppresses muscle protein breakdown, and promotes net muscle protein accretion for several hours. These acute observations form the basis for strategized protein intake to promote lean mass accretion, or prevent lean mass loss over the long term. However, factors such as protein dose, protein source, and timing of intake are important in mediating the anabolic effects of amino acids on skeletal muscle and must be considered within the context of evaluating the reported efficacy of long-term studies investigating protein supplementation as part of a dietary strategy to promote lean mass accretion and/or prevent lean mass loss. Current research suggests that dietary protein supplementation can augment resistance exercise-mediated gains in skeletal muscle mass and strength and can preserve skeletal muscle mass during periods of diet-induced energy restriction. Perhaps less appreciated, protein supplementation can augment resistance training-mediated gains in skeletal muscle mass even in individuals habitually consuming 'adequate' (i.e., >0.8 g kg⁻¹ day⁻¹) protein. Additionally, overfeeding energy with moderate to high-protein intake (15-25 % protein or 1.8-3.0 g kg⁻¹ day⁻¹) is associated with lean, but not fat mass accretion, when compared to overfeeding energy with low protein intake (5 % protein or ~0.68 g kg⁻¹ day⁻¹). Amino acids represent primary nutrient regulators of skeletal muscle anabolism, capable of enhancing lean mass accretion with resistance exercise and attenuating the loss of lean mass during periods of energy deficit, although factors such as protein dose, protein source, and timing of intake are likely important in mediating these effects.

Contact in an expanding universe: an instructive exercise in dynamic geometry

NASA Astrophysics Data System (ADS)

Zimmerman, Seth

2010-11-01

The particular problem solved in this paper is that of calculating the time required to overtake a distant object receding under cosmic expansion, and the speed at which that object is passed. This is a rarely investigated problem leading to some interesting apparent paradoxes. We employ the problem to promote a deeper understanding of the dynamic geometry behind the expansion of space in three eras, especially for physics undergraduates. We do not utilize the standard cosmological formulae, but deliberately take a simpler approach, comprehensible to any student comfortable with differentials. This should offer an intuitive preparation for later courses in general relativity. The paper can be read straight through, or offered to a class in segments as problems to investigate. The overall intention is to leave students with a more tangible grasp of expanding space.

The effect of exercise therapy on knee osteoarthritis: a randomized clinical trial

PubMed Central

Nejati, Parisa; Farzinmehr, Azizeh; Moradi-Lakeh, Maziar

2015-01-01

Background: Knee osteoarthritis (OA) is the most common musculoskeletal disease among old individuals which affects ability for sitting on the chair, standing, walking and climbing stairs. Our objective was to investigate the short and long-term effects of the most simple and the least expensive exercise protocols in combination to conventional conservative therapy for knee OA. Methods: It was a single blind RCT study with a 12-months follow-up. Totally, 56 patients with knee OA were assigned into 2 random groups. The patients in exercise group received exercise for knee muscles in combination with non-steroid anti-inflammatory drugs (NSAIDs) and 10 sessions acupuncture and physiotherapy modalities. Non-exercise group received similar treatments except exercise program. The changes in patients’ pain and functional status were evaluated by visual analog scale (VAS), knee and osteoarthritis outcome score (KOOS) questionnaire and functional tests (4 steps, 5 sit up, and 6 min walk test) before and after treatment (1 and 3 months after intervention), and 1 year later at the follow-up. Results: The results showed that the patients with knee OA in exercise group had significant improvement in pain, disability, walking, stair climbing, and sit up speed after treatment at first and second follow-up when compared with their initial status and when compared with non-exercise group. At third follow up (1 year later) there was significant difference between groups in VAS and in three items of KOOS questionnaire in functional status. Conclusion: Non aerobic exercises for muscles around knee can augment the effect of other therapeutic interventions like medical therapy, acupuncture, and modalities for knee OA. PMID:26034739

Rationale and design of REWARD (revving-up exercise for sustained weight loss by altering neurological reward and drive): a randomized trial in obese endometrial cancer survivors.

PubMed

Nock, Nora L; Dimitropoulos, Anastasia; Rao, Stephen M; Flask, Chris A; Schluchter, Mark; Zanotti, Kristine M; Rose, Peter G; Kirwan, John P; Alberts, Jay

2014-11-01

Obesity is a leading risk factor for endometrial cancer (EC), particularly Type I forms, which are increasing in the U.S. Although death rates from most cancers have been decreasing, overall mortality in EC is increasing in the U.S. EC survivors' poor fitness combined with their surgical treatments may make weight loss particularly challenging. High intensity exercise increases neurotrophins and neurological reward via altered striatal dopamine in animals, and, in humans, chronic high intensity exercise enhances meal-induced satiety and may reduce hedonic eating. "Assisted" exercise, a mode of exercise whereby a patient's voluntary exercise rate is augmented mechanically, may modulate brain dopamine levels in Parkinson's Disease patients but has not been previously evaluated as a treatment for obesity. We describe the rationale and design of the REWARD trial, which has the overarching goal of randomizing 120 obese EC survivors to "assisted" or voluntary rate cycling to evaluate the efficacy of "assisted" exercise in enhancing and sustaining weight loss. Patients in both arms will receive 3 days/week of supervised exercise and 1 day/week of a group dietary behavioral intervention for 16 weeks and, then, will be followed for 6 months. The primary outcome is weight loss. Secondary outcomes include measures for body composition, fitness, eating behavior, exercise motivation and, quality of life as well as cognition and food reward and motivation as assessed by functional magnetic resonance imaging (fMRI) tasks. If successful, the REWARD program could be extended to help sustain weight loss in obese cancer and non-cancer patients. Copyright © 2014 Elsevier Inc. All rights reserved.

Acute exercises induce disorders of the gastrointestinal integrity in a murine model.

PubMed

Gutekunst, Katrin; Krüger, Karsten; August, Christian; Diener, Martin; Mooren, Frank-Christoph

2014-03-01

Many endurance athletes complain about gastrointestinal (GI) symptoms. It is assumed that exercise-induced shift of perfusion with consecutive hypoperfusion of the enteral vascular system leads to an increased GI permeability and tissue damage. Therefore, the aim of the study was to investigate permeability, apoptosis, electrogenic ion transport (Isc), and tissue conductance (Gt) of the small intestine in a murine exercise model. After spirometry, male Swiss CD-1 mice were subjected to an intensive treadmill exercise (80% VO2max). Sedentary mice served as controls. The small intestine was removed at several time intervals post-exercise. Apoptotic cells were determined by the TUNEL method, while fluorescein isothiocyanate dextran permeation indicated intestinal permeability. The Gt and Isc measurements were carried out in a modified Ussing chamber. Apoptosis of epithelial cells increased continuously until 24 h post exercise (0.8 ± 0.42 versus 39.2 ± 26.0%; p < 0.05). Compared with the control group the permeability increased 2 h after exercise (0.47 ± 0.07 versus 0.67 ± 0.14 FU/min; p < 0.05). Isc measurements of the ileum were augmented after 24 h (3.33 ± 0.56 versus 5.77 ± 1.16 μEq/h/cm(2); p < 0.05). At this time the Gt increased as well (28.8 ± 3.37 versus 32.5 ± 2.59 mS/cm(2); p < 0.05). In the murine exercise model there is evidence that after intense endurance exercise repair processes occur in small intestinal epithelial cells, which affect permeability, Gt, and Isc. The formation of lamellipodia to close the "leaky" tight junctions caused by apoptosis might be an underlying mechanism.

Cerebral Blood Flow Responses to Aquatic Treadmill Exercise.

PubMed

Parfitt, Rhodri; Hensman, Marianne Y; Lucas, Samuel J E

2017-07-01

Aquatic treadmills are used as a rehabilitation method for conditions such as spinal cord injury, osteoarthritis, and stroke, and can facilitate an earlier return to exercise training for athletes. However, their effect on cerebral blood flow (CBF) responses has not been examined. We tested the hypothesis that aquatic treadmill exercise would augment CBF and lower HR compared with land-based treadmill exercise. Eleven participants completed incremental exercise (crossover design) starting from walking pace (4 km·h, immersed to iliac crest [aquatic], 6 km·h [land]) and increasing 1 km·h every 2 min up to 10 km·h for aquatic (maximum belt speed) or 12 km·h for land. After this, participants completed two 2-min bouts of exercise immersed to midthigh and midchest at constant submaximal speed (aquatic), or were ramped to exhaustion (land; increased gradient 2° every min). Middle cerebral artery blood flow velocity (MCAv) and HR were measured throughout, and the initial 10 min of each protocol and responses at each immersion level were compared. Compared with land-based treadmill, MCAvmean increased more from baseline for aquatic exercise (21% vs 12%, P < 0.001), while being associated with lower overall HR (pooled difference, 11 bpm; P < 0.001). MCAvmean increased similarly during aquatic walking compared with land-based moderate intensity running (~10 cm·s, P = 0.56). Greater water immersion lowered HR (139 vs 178 bpm for midchest vs midthigh), whereas MCAvmean remained constant (P = 0.37). Findings illustrate the potential for aquatic treadmill exercise to enhance exercise-induced elevations in CBF and thus optimize shear stress-mediated adaptation of the cerebrovasculature.

Carbohydrate feeding during recovery alters the skeletal muscle metabolic response to repeated sessions of high-intensity interval exercise in humans.

PubMed

Cochran, Andrew J R; Little, Jonathan P; Tarnopolsky, Mark A; Gibala, Martin J

2010-03-01

Exercise training under conditions of reduced carbohydrate (CHO) availability has been reported to augment gains in skeletal muscle oxidative capacity; however, the underlying mechanisms are unclear. We examined the effect of manipulating CHO intake on the acute metabolic response to high-intensity interval exercise, including signaling cascades linked to mitochondrial biogenesis. Ten men performed two trials in random order separated by >or=1 wk. Each trial consisted of a morning (AM) and afternoon (PM) training session (5 x 4 min cycling at approximately 90-95% of heart rate reserve) separated by 3 h of recovery during which subjects ingested a high-CHO drink (HI-HI) or nonenergetic placebo (HI-LO) before PM exercise. Biopsies (vastus lateralis) revealed that muscle phosphocreatine and ATP content were similar after AM exercise but decreased to a greater extent during PM exercise in HI-LO vs. HI-HI. Phosphorylation of p38 mitogen-activated protein kinase (MAPK) and AMP-activated protein kinase (AMPK) increased approximately 4-fold and 2-fold, respectively, during AM exercise with no difference between conditions. After PM exercise, p38 MAPK phosphorylation was higher in HI-LO vs. HI-HI, whereas AMPK was not different between conditions. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha) gene expression increased approximately 8-fold during recovery from AM exercise and remained elevated during PM exercise with no differences between conditions. Cytochrome oxidase subunit 4 (COXIV) mRNA was also elevated 3 h after AM exercise, with no difference between conditions. These data provide evidence that p38 MAPK is a nutrient-sensitive signaling molecule that could be involved in the altered skeletal muscle adaptive response reported after exercise training under conditions of restricted CHO intake, but further research is required to confirm this hypothesis.

Aerobic Exercise for Reducing Migraine Burden: Mechanisms, Markers, and Models of Change Processes

PubMed Central

Irby, Megan B.; Bond, Dale S.; Lipton, Richard B.; Nicklas, Barbara; Houle, Timothy T.; Penzien, Donald B.

2016-01-01

Background Engagement in regular exercise routinely is recommended as an intervention for managing and preventing migraine, and yet empirical support is far from definitive. We possess at best a weak understanding of how aerobic exercise and resulting change in aerobic capacity influence migraine, let alone the optimal parameters for exercise regimens as migraine therapy (eg, who will benefit, when to prescribe, optimal types, and doses/intensities of exercise, level of anticipated benefit). These fundamental knowledge gaps critically limit our capacity to deploy exercise as an intervention for migraine. Overview Clear articulation of the markers and mechanisms through which aerobic exercise confers benefits for migraine would prove invaluable and could yield insights on migraine pathophysiology. Neurovascular and neuroinflammatory pathways, including an effect on obesity or adiposity, are obvious candidates for study given their role both in migraine as well as the changes known to accrue with regular exercise. In addition to these biological pathways, improvements in aerobic fitness and migraine alike also are mediated by changes in psychological and sociocognitive factors. Indeed a number of specific mechanisms and pathways likely are operational in the relationship between exercise and migraine improvement, and it remains to be established whether these pathways operate in parallel or synergistically. As heuristics that might conceptually benefit our research programs here forward, we: (1) provide an extensive listing of potential mechanisms and markers that could account for the effects of aerobic exercise on migraine and are worthy of empirical exploration and (2) present two exemplar conceptual models depicting pathways through which exercise may serve to reduce the burden of migraine. Conclusion Should the promise of aerobic exercise as a feasible and effective migraine therapy be realized, this line of endeavor stands to benefit migraineurs (including the many who presently remain suboptimally treated) by providing a new therapeutic avenue as an alternative or augmentative compliment to established interventions for migraine. PMID:26643584

Aerobic Exercise for Reducing Migraine Burden: Mechanisms, Markers, and Models of Change Processes.

PubMed

Irby, Megan B; Bond, Dale S; Lipton, Richard B; Nicklas, Barbara; Houle, Timothy T; Penzien, Donald B

2016-02-01

Engagement in regular exercise routinely is recommended as an intervention for managing and preventing migraine, and yet empirical support is far from definitive. We possess at best a weak understanding of how aerobic exercise and resulting change in aerobic capacity influence migraine, let alone the optimal parameters for exercise regimens as migraine therapy (eg, who will benefit, when to prescribe, optimal types, and doses/intensities of exercise, level of anticipated benefit). These fundamental knowledge gaps critically limit our capacity to deploy exercise as an intervention for migraine. Clear articulation of the markers and mechanisms through which aerobic exercise confers benefits for migraine would prove invaluable and could yield insights on migraine pathophysiology. Neurovascular and neuroinflammatory pathways, including an effect on obesity or adiposity, are obvious candidates for study given their role both in migraine as well as the changes known to accrue with regular exercise. In addition to these biological pathways, improvements in aerobic fitness and migraine alike also are mediated by changes in psychological and sociocognitive factors. Indeed a number of specific mechanisms and pathways likely are operational in the relationship between exercise and migraine improvement, and it remains to be established whether these pathways operate in parallel or synergistically. As heuristics that might conceptually benefit our research programs here forward, we: (1) provide an extensive listing of potential mechanisms and markers that could account for the effects of aerobic exercise on migraine and are worthy of empirical exploration and (2) present two exemplar conceptual models depicting pathways through which exercise may serve to reduce the burden of migraine. Should the promise of aerobic exercise as a feasible and effective migraine therapy be realized, this line of endeavor stands to benefit migraineurs (including the many who presently remain suboptimally treated) by providing a new therapeutic avenue as an alternative or augmentative compliment to established interventions for migraine. © 2015 American Headache Society.

The Observation of Manual Grasp Actions Affects the Control of Speech: A Combined Behavioral and Transcranial Magnetic Stimulation Study

ERIC Educational Resources Information Center

Gentilucci, Maurizio; Campione, Giovanna Cristina; Volta, Riccardo Dalla; Bernardis, Paolo

2009-01-01

Does the mirror system affect the control of speech? This issue was addressed in behavioral and Transcranial Magnetic Stimulation (TMS) experiments. In behavioral experiment 1, participants pronounced the syllable /da/ while observing (1) a hand grasping large and small objects with power and precision grasps, respectively, (2) a foot interacting…

Development of Reaching and Grasping Skills in Infants with Down Syndrome

ERIC Educational Resources Information Center

de Campos, Ana Carolina; Rocha, Nelci Adriana Cicuto Ferreira; Savelsbergh, Geert J. P.

2010-01-01

Reaching and grasping skills have been described to emerge from a dynamic interaction between intrinsic and extrinsic factors. The aims of the study were to investigate the effect of such intrinsic factors as age and Down syndrome on the development of reaching and grasping skills and on overall gross motor skill, and to test the influence of the…

Augmenting Our Influence: Alliance Revitalization and Partner Development

DTIC Science & Technology

2014-04-01

actual sub- stance over cosmetics remains to be determined. Broadening Regional Partnerships. Widening the network of U.S. security ties to in- clude...of Virginia, February 20, 2013; Clinton, pp. 13-24; Condoleezza Rice , “Remarks at the U.S. University Presidents Summit on Interna- tional Education...require the showing of presence, such as rotational naval exercises in the Bal- tic Sea and Black Sea conducted by U.S. Naval Forces Europe and

Metrics of Software Quality.

DTIC Science & Technology

1980-11-01

Systems: A Raytheon Project History", RADC-TR-77-188, Final Technical Report, June 1977. 4. IBM Federal Systems Division, "Statistical Prediction of...147, June 1979. 4. W. D. Brooks, R. W. Motley, "Analysis of Discrete Software Reliability Models", IBM Corp., RADC-TR-80-84, RADC, New York, April 1980...J. C. King of IBM (Reference 9) and Lori A. Clark (Reference 10) of the University of Massachusetts. Programs, so exercised must be augmented so they

Political Kidnappings in Turkey, 1971-1972

DTIC Science & Technology

1977-07-01

diet , one TPLA member replied, "No, your minds must be clear in case you have to make an important decision." The hostages never learned what that...and inadequate exercise and diet augmented the intense anxiety and discomfort they suffered. As has happened in other polit- ical kidnappings, the...card from one of the airmen. Meanwhile, after his arrest, Ertekin had revealed the names of the group members, and the GOT learned that four of the

Fuzzy Logic Controller Design for A Robot Grasping System with Different Membership Functions

NASA Astrophysics Data System (ADS)

Ahmad, Hamzah; Razali, Saifudin; Rusllim Mohamed, Mohd

2013-12-01

This paper investigates the effects of the membership function to the object grasping for a three fingered gripper system. The performance of three famously used membership functions is compared to identify their behavior in lifting a defined object shape. MATLAB Simulink and SimMechanics toolboxes are used to examine the performance. Our preliminary results proposed that the Gaussian membership function surpassed the two other membership functions; triangular and trapezoid memberships especially in the context of firmer grasping and less time consumption during operations. Therefore, Gaussian membership function could be the best solution when time consumption and firmer grasp are considered.

Instrumented toys for studying power and precision grasp forces in infants.

PubMed

Serio, S M; Cecchi, F; Boldrini, E; Laschi, C; Sgandurra, G; Cioni, G; Dario, P

2011-01-01

Currently the study of infants grasping development is purely clinical, based on functional scales or on the observation of the infant while playing; no quantitative variables are measured or known for diagnosis of eventually disturbed development. The aim of this work is to show the results of a longitudinal study achieved by using a "baby gym" composed by a set of instrumented toys, as a tool to measure and stimulate grasping actions, in infants from 4 to 9 months of life. The study has been carried out with 7 healthy infants and it was observed, during infants development, an increase of precision grasp and a reduction of power grasp with age. Moreover the forces applied for performing both precision and power grasp increase with age. The proposed devices represent a valid tool for continuous and quantitative measuring infants manual function and motor development, without being distressful for the infant and consequently it could be suitable for early intervention training during the first year of life. The same system, in fact, could be used with infants at high risk for developmental motor disorder in order to evaluate any potential difference from control healthy infants.

Hypertensive response to exercise: mechanisms and clinical implication.

PubMed

Kim, Darae; Ha, Jong-Won

2016-01-01

A hypertensive response to exercise (HRE) is frequently observed in individuals without hypertension or other cardiovascular disease. However, mechanisms and clinical implication of HRE is not fully elucidated. Endothelial dysfunction and increased stiffness of large artery contribute to development of HRE. From neurohormonal aspects, excess stimulation of sympathetic nervous system and augmented rise of angiotensin II seems to be important mechanism in HRE. Increasing evidences indicates that a HRE is associated with functional and structural abnormalities of left ventricle, especially when accompanied by increased central blood pressure. A HRE harbors prognostic significance in future development of hypertension and increased cardiovascular events, particularly if a HRE is documented in moderate intensity of exercise. As supported by previous studies, a HRE is not a benign phenomenon, however, currently, whether to treat a HRE is controversial with uncertain treatment strategy. Considering underlying mechanisms, angiotensin receptor blockers and beta blockers can be suggested in individuals with HRE, however, evidences for efficacy and outcomes of treatment of HRE in individuals without hypertension is scarce and therefore warrants further studies.

Canine obesity: an overview.

PubMed

Gossellin, J; Wren, J A; Sunderland, S J

2007-08-01

Canine patients are generally regarded as being clinically obese when their body weight is at least 15% above ideal. The incidence of obesity in dogs is thought to be in the range of 20-40% of the general population and, since obesity is known to predispose or exacerbate a range of serious medical conditions, its importance cannot be overstated. Management of obesity through dietary restriction and increased exercise is often difficult to achieve and dependent upon owner compliance. Until recently there has been no authorized therapeutic medication available for weight reduction in dogs, and drugs used in people have proved unsuitable. However, with the development of microsomal triglyceride transfer protein inhibitors for canine use, such as dirlotapide, the veterinarian has a novel method with which to augment traditional weight control programmes. This approach has the additional advantage that weight loss is achieved without dietary restriction or change in exercise regimen, providing encouragement for the owner to comply with subsequent dietary and exercise recommendations, thereby increasing the likelihood for long-term success.

Influence of low versus moderate glycemic index of diet on substrate oxidation and energy expenditure during incremental exercise in endurance athletes: a randomized counterbalanced cross-over trial.

PubMed

Durkalec-Michalski, Krzysztof; Zawieja, Emilia Ewa; Zawieja, Bogna Ewa; Podgórski, Tomasz; Jurkowska, Dominika; Jeszka, Jan

2017-12-18

The study was aimed at assessing the influence of 3-week low glycemic index (LGI) versus moderate glycemic index (MGI) diet on substrate oxidation during incremental exercise. 17 runners completed two 3-week trials of either LGI or MGI diet in a randomised counterbalanced manner. Before and after each trial the incremental cycling test was performed. Metabolic alternations were observed only within tested diets and no significant differences in fat and carbohydrate (CHO) oxidation were found between MGI and LGI diets. Following MGI diet CHO oxidation rate increased. The AUC of fat oxidation decreased after both diets. Percent contribution of fat to energy yield declined, whereas contribution of CHO was augmented following MGI diet. This study indicates that the 3-week MGI diet increased the rate of carbohydrate oxidation during incremental cycling test and improved performance in acute intense exercise test, while both high-carbohydrate diets downregulated fat oxidation rate.

Dependence of behavioral performance on material category in an object grasping task with monkeys.

PubMed

Yokoi, Isao; Tachibana, Atsumichi; Minamimoto, Takafumi; Goda, Naokazu; Komatsu, Hidehiko

2018-05-02

Material perception is an essential part of our cognitive function that enables us to properly interact with our complex daily environment. One important aspect of material perception is its multimodal nature. When we see an object, we generally recognize its haptic properties as well as its visual properties. Consequently, one must examine behavior using real objects that are perceived both visually and haptically to fully understand the characteristics of material perception. As a first step, we examined whether there is any difference in the behavioral responses to different materials in monkeys trained to perform an object grasping task in which they saw and grasped rod-shaped real objects made of various materials. We found that the monkeys' behavior in the grasping task, measured based on the success rate and the pulling force, differed depending on the material category. Monkeys easily and correctly grasped objects of some materials, such as metal and glass, but failed to grasp objects of other materials. In particular, monkeys avoided grasping fur-covered objects. The differences in the behavioral responses to the material categories cannot be explained solely based on the degree of familiarity with the different materials. These results shed light on the organization of multimodal representation of materials, where their biological significance is an important factor. In addition, a monkey that avoided touching real fur-covered objects readily touched images of the same objects presented on a CRT display. This suggests employing real objects is important when studying behaviors related to material perception.

The origins of thalamic inputs to grasp zones in frontal cortex of macaque monkeys

PubMed Central

Stepniewska, Iwona; Kaas, Jon H.

2015-01-01

The hand representation in primary motor cortex (M1) is instrumental to manual dexterity in primates. In Old World monkeys, rostral and caudal aspects of the hand representation are located in the precentral gyrus and the anterior bank of the central sulcus, respectively. We previously reported the organization of the cortico-cortical connections of the grasp zone in rostral M1. Here we describe the organization of thalamocortical connections that were labeled from the same tracer injections. Thalamocortical connections of a grasp zone in ventral premotor cortex (PMv) and the M1 orofacial representation are included for direct comparison. The M1 grasp zone was primarily connected with ventral lateral divisions of motor thalamus. The largest proportion of inputs originated in the posterior division (VLp) followed by the medial and the anterior divisions. Thalamic inputs to the M1 grasp zone originated in more lateral aspects of VLp as compared to the origins of thalamic inputs to the M1 orofacial representation. Inputs to M1 from thalamic divisions connected with cerebellum constituted three fold the density of inputs from divisions connected with basal ganglia, whereas the ratio of inputs was more balanced for the grasp zone in PMv. Privileged access of the cerebellothalamic pathway to the grasp zone in rostral M1 is consistent with the connection patterns previously reported for the precentral gyrus. Thus, cerebellar nuclei are likely more involved than basal ganglia nuclei with the contributions of rostral M1 to manual dexterity. PMID:26254903

A rehabilitation device to improve the hand grasp function of stroke patients using a patient-driven approach.

PubMed

Park, Wanjoo; Jeong, Wookjin; Kwon, Gyu-Hyun; Kim, Yun-Hee; Kim, Laehyun

2013-06-01

This paper proposes a robotic hand rehabilitation device for grasp training. The device is designed for stroke patients to train and recover their hand grasp function in order to undertake activities of daily living (ADL). The device consists of a control unit, two small actuators, an infrared (IR) sensor, and pressure sensors in the grasp handle. The advantages of this device are that it is small in size, inexpensive, and available for use at home without specialist's supervision. In addition, a novel patient-driven strategy based on the patient's movement intention detected by the pressure sensors without bio-signals is introduced. Once the system detects a patient's movement intention, it triggers the robotic device to move the patient's hand to form the normal grasping behavior. This strategy may encourage stroke patients to participate in rehabilitation training to recover their hand grasp function and it may also enhance neural plasticity. A user study was conducted in order to investigate the usability, acceptability, satisfaction, and suggestions for improvement of the proposed device. The results of this survey included positive reviews from therapists and a stroke patient. In particular, therapists expected that the proposed patient-driven mode can motivate patients for their rehabilitation training and it can be effective to prevent a compensational strategy in active movements. It is expected that the proposed device will assist stroke patients in restoring their grasp function efficiently.

The origins of thalamic inputs to grasp zones in frontal cortex of macaque monkeys.

PubMed

Gharbawie, Omar A; Stepniewska, Iwona; Kaas, Jon H

2016-07-01

The hand representation in primary motor cortex (M1) is instrumental to manual dexterity in primates. In Old World monkeys, rostral and caudal aspects of the hand representation are located in the precentral gyrus and the anterior bank of the central sulcus, respectively. We previously reported the organization of the cortico-cortical connections of the grasp zone in rostral M1. Here we describe the organization of thalamocortical connections that were labeled from the same tracer injections. Thalamocortical connections of a grasp zone in ventral premotor cortex (PMv) and the M1 orofacial representation are included for direct comparison. The M1 grasp zone was primarily connected with ventral lateral divisions of motor thalamus. The largest proportion of inputs originated in the posterior division (VLp) followed by the medial and the anterior divisions. Thalamic inputs to the M1 grasp zone originated in more lateral aspects of VLp as compared to the origins of thalamic inputs to the M1 orofacial representation. Inputs to M1 from thalamic divisions connected with cerebellum constituted three fold the density of inputs from divisions connected with basal ganglia, whereas the ratio of inputs was more balanced for the grasp zone in PMv. Privileged access of the cerebellothalamic pathway to the grasp zone in rostral M1 is consistent with the connection patterns previously reported for the precentral gyrus. Thus, cerebellar nuclei are likely more involved than basal ganglia nuclei with the contributions of rostral M1 to manual dexterity.

Improving Fine Control of Grasping Force during Hand–Object Interactions for a Soft Synergy-Inspired Myoelectric Prosthetic Hand

PubMed Central

Fu, Qiushi; Santello, Marco

2018-01-01

The concept of postural synergies of the human hand has been shown to potentially reduce complexity in the neuromuscular control of grasping. By merging this concept with soft robotics approaches, a multi degrees of freedom soft-synergy prosthetic hand [SoftHand-Pro (SHP)] was created. The mechanical innovation of the SHP enables adaptive and robust functional grasps with simple and intuitive myoelectric control from only two surface electromyogram (sEMG) channels. However, the current myoelectric controller has very limited capability for fine control of grasp forces. We addressed this challenge by designing a hybrid-gain myoelectric controller that switches control gains based on the sensorimotor state of the SHP. This controller was tested against a conventional single-gain (SG) controller, as well as against native hand in able-bodied subjects. We used the following tasks to evaluate the performance of grasp force control: (1) pick and place objects with different size, weight, and fragility levels using power or precision grasp and (2) squeezing objects with different stiffness. Sensory feedback of the grasp forces was provided to the user through a non-invasive, mechanotactile haptic feedback device mounted on the upper arm. We demonstrated that the novel hybrid controller enabled superior task completion speed and fine force control over SG controller in object pick-and-place tasks. We also found that the performance of the hybrid controller qualitatively agrees with the performance of native human hands. PMID:29375360

Comparing "pick and place" task in spatial Augmented Reality versus non-immersive Virtual Reality for rehabilitation setting.

PubMed

Khademi, Maryam; Hondori, Hossein Mousavi; Dodakian, Lucy; Cramer, Steve; Lopes, Cristina V

2013-01-01

Introducing computer games to the rehabilitation market led to development of numerous Virtual Reality (VR) training applications. Although VR has provided tremendous benefit to the patients and caregivers, it has inherent limitations, some of which might be solved by replacing it with Augmented Reality (AR). The task of pick-and-place, which is part of many activities of daily living (ADL's), is one of the major affected functions stroke patients mainly expect to recover. We developed an exercise consisting of moving an object between various points, following a flash light that indicates the next target. The results show superior performance of subjects in spatial AR versus non-immersive VR setting. This could be due to the extraneous hand-eye coordination which exists in VR whereas it is eliminated in spatial AR.

Disaster medicine through Google Glass.

PubMed

Carenzo, Luca; Barra, Federico Lorenzo; Ingrassia, Pier Luigi; Colombo, Davide; Costa, Alessandro; Della Corte, Francesco

2015-06-01

Nontechnical skills can make a difference in the management of disasters and mass casualty incidents and any tool helping providers in action might improve their ability to respond to such events. Google Glass, released by Google as a new personal communication device, could play a role in this field. We recently tested Google Glass during a full-scale exercise to perform visually guided augmented-reality Simple Triage and Rapid Treatment triage using a custom-made application and to identify casualties and collect georeferenced notes, photos, and videos to be incorporated into the debriefing. Despite some limitations (battery life and privacy concerns), Glass is a promising technology both for telemedicine applications and augmented-reality disaster response support to increase operators' performance, helping them to make better choices on the field; to optimize timings; and finally represents an excellent option to take professional education to a higher level.

Differential effects of aging and exercise on intra-abdominal adipose arteriolar function and blood flow regulation

PubMed Central

Davis, Robert T.; Stabley, John N.; Dominguez, James M.; Ramsey, Michael W.; McCullough, Danielle J.; Lesniewski, Lisa A.; Delp, Michael D.

2013-01-01

Adipose tissue (AT), which typically comprises an increased percentage of body mass with advancing age, receives a large proportion of resting cardiac output. During exercise, an old age-associated inability to increase vascular resistance within the intra-abdominal AT may compromise the ability of the cardiovascular system to redistribute blood flow to the active musculature, contributing to the decline in exercise capacity observed in this population. We tested the hypotheses that 1) there would be an elevated perfusion of AT during exercise with old age that was associated with diminished vasoconstrictor responses of adipose-resistance arteries, and 2) chronic exercise training would mitigate the age-associated alterations in AT blood flow and vascular function. Young (6 mo; n = 40) and old (24 mo; n = 28) male Fischer 344 rats were divided into young sedentary (YSed), old sedentary (OSed), young exercise trained (YET), or old exercise trained (OET) groups, where training consisted of 10-12 wk of treadmill exercise. In vivo blood flow at rest and during exercise and in vitro α-adrenergic and myogenic vasoconstrictor responses in resistance arteries from AT were measured in all groups. In response to exercise, there was a directionally opposite change in AT blood flow in the OSed group (∼150% increase) and YSed (∼55% decrease) vs. resting values. Both α-adrenergic and myogenic vasoconstriction were diminished in OSed vs. YSed AT-resistance arteries. Exercise training resulted in a similar AT hyperemic response between age groups during exercise (YET, 9.9 ± 0.5 ml·min−1·100−1 g; OET, 8.1 ± 0.9 ml·min−1·100−1 g) and was associated with enhanced myogenic and α-adrenergic vasoconstriction of AT-resistance arteries from the OET group relative to OSed. These results indicate that there is an inability to increase vascular resistance in AT during exercise with old age, due, in part, to a diminished vasoconstriction of AT arteries. Furthermore, the results indicate that exercise training can augment vasoconstriction of AT arteries and mitigate age-related alterations in the regulation of AT blood flow during exercise. PMID:23349454

Effects of Multiple Planning Constraints on the Development of Grasp Posture Planning in 6- to 10-Year-Old Children

ERIC Educational Resources Information Center

Stöckel, Tino; Hughes, Charmayne M. L.

2015-01-01

This experiment examined how multiple planning constraints affect grasp posture planning in 6- to 10-year-old children (n = 16 in each group) by manipulating the intended object end-orientation (left end-down, right end-down) and initial precision demands (standard, initial precision) of a bar transport task. Results indicated that grasp posture…

Changes in performance over time while learning to use a myoelectric prosthesis

PubMed Central

2014-01-01

Background Training increases the functional use of an upper limb prosthesis, but little is known about how people learn to use their prosthesis. The aim of this study was to describe the changes in performance with an upper limb myoelectric prosthesis during practice. The results provide a basis to develop an evidence-based training program. Methods Thirty-one able-bodied participants took part in an experiment as well as thirty-one age- and gender-matched controls. Participants in the experimental condition, randomly assigned to one of four groups, practiced with a myoelectric simulator for five sessions in a two-weeks period. Group 1 practiced direct grasping, Group 2 practiced indirect grasping, Group 3 practiced fixating, and Group 4 practiced a combination of all three tasks. The Southampton Hand Assessment Procedure (SHAP) was assessed in a pretest, posttest, and two retention tests. Participants in the control condition performed SHAP two times, two weeks apart with no practice in between. Compressible objects were used in the grasping tasks. Changes in end-point kinematics, joint angles, and grip force control, the latter measured by magnitude of object compression, were examined. Results The experimental groups improved more on SHAP than the control group. Interestingly, the fixation group improved comparable to the other training groups on the SHAP. Improvement in global position of the prosthesis leveled off after three practice sessions, whereas learning to control grip force required more time. The indirect grasping group had the smallest object compression in the beginning and this did not change over time, whereas the direct grasping and the combination group had a decrease in compression over time. Moreover, the indirect grasping group had the smallest grasping time that did not vary over object rigidity, while for the other two groups the grasping time decreased with an increase in object rigidity. Conclusions A training program should spend more time on learning fine control aspects of the prosthetic hand during rehabilitation. Moreover, training should start with the indirect grasping task that has the best performance, which is probably due to the higher amount of useful information available from the sound hand. PMID:24568148

Multisession, noninvasive closed-loop neuroprosthetic control of grasping by upper limb amputees.

PubMed

Agashe, H A; Paek, A Y; Contreras-Vidal, J L

2016-01-01

Upper limb amputation results in a severe reduction in the quality of life of affected individuals due to their inability to easily perform activities of daily living. Brain-machine interfaces (BMIs) that translate grasping intent from the brain's neural activity into prosthetic control may increase the level of natural control currently available in myoelectric prostheses. Current BMI techniques demonstrate accurate arm position and single degree-of-freedom grasp control but are invasive and require daily recalibration. In this study we tested if transradial amputees (A1 and A2) could control grasp preshaping in a prosthetic device using a noninvasive electroencephalography (EEG)-based closed-loop BMI system. Participants attempted to grasp presented objects by controlling two grasping synergies, in 12 sessions performed over 5 weeks. Prior to closed-loop control, the first six sessions included a decoder calibration phase using action observation by the participants; thereafter, the decoder was fixed to examine neuroprosthetic performance in the absence of decoder recalibration. Ability of participants to control the prosthetic was measured by the success rate of grasping; ie, the percentage of trials within a session in which presented objects were successfully grasped. Participant A1 maintained a steady success rate (63±3%) across sessions (significantly above chance [41±5%] for 11 sessions). Participant A2, who was under the influence of pharmacological treatment for depression, hormone imbalance, pain management (for phantom pain as well as shoulder joint inflammation), and drug dependence, achieved a success rate of 32±2% across sessions (significantly above chance [27±5%] in only two sessions). EEG signal quality was stable across sessions, but the decoders created during the first six sessions showed variation, indicating EEG features relevant to decoding at a smaller timescale (100ms) may not be stable. Overall, our results show that (a) an EEG-based BMI for grasping is a feasible strategy for further investigation of prosthetic control by amputees, and (b) factors that may affect brain activity such as medication need further examination to improve accuracy and stability of BMI performance. © 2016 Elsevier B.V. All rights reserved.

Yohimbine enhancement of exposure therapy for social anxiety disorder: a randomized controlled trial.

PubMed

Smits, Jasper A J; Rosenfield, David; Davis, Michelle L; Julian, Kristin; Handelsman, Pamela R; Otto, Michael W; Tuerk, Peter; Shiekh, Michael; Rosenfield, Ben; Hofmann, Stefan G; Powers, Mark B

2014-06-01

Preclinical and clinical trials suggest that yohimbine may augment extinction learning without significant side effects. However, previous clinical trials have only examined adults with specific phobias. Yohimbine has not yet been investigated in the augmentation of exposure therapy for other anxiety disorders. Adults (n = 40) with a DSM-IV diagnosis of social anxiety disorder were randomized to placebo or yohimbine HCl (10.8 mg) 1 hour before each of four exposure sessions. Outcome measures were collected at baseline, each treatment session, posttreatment, and 1-month follow-up. Yohimbine was well tolerated. Yohimbine augmentation, relative to placebo augmentation, resulted in faster improvement and better outcomes on self-report measures of social anxiety disorder severity (Liebowitz Social Anxiety Scale, d = .53) and depressed mood severity (Beck Depression Inventory, d = .37) but not on the clinician-rated measures (Clinical Global Impressions-Severity Scale, d = .09; Clinical Global Impressions-Improvement Scale, d = .25). Between-group differences on the Liebowitz Social Anxiety Scale were moderated by the level of fear reported at the end of an exposure exercise (end fear), such that the advantage of yohimbine over placebo was only evident among patients who reported low end fear. The results provide moderate support for yohimbine as a therapeutic augmentation strategy for exposure therapy in social anxiety disorder, one that may be especially effective when coupled with successful exposure experiences. Beneficial effects for yohimbine were readily evident for self-report measures but not for clinician-rated outcomes of social anxiety severity and improvement. © 2013 Society of Biological Psychiatry Published by Society of Biological Psychiatry All rights reserved.

Feasibility of virtual reality augmented cycling for health promotion of people poststroke.

PubMed

Deutsch, Judith E; Myslinski, Mary Jane; Kafri, Michal; Ranky, Richard; Sivak, Mark; Mavroidis, Constantinos; Lewis, Jeffrey A

2013-09-01

A virtual reality (VR) augmented cycling kit (VRACK) was developed to address motor control and fitness deficits of individuals with chronic stroke. In this article, we report on the safety, feasibility, and efficacy of using the VR augmented cycling kit to improve cardiorespiratory (CR) fitness of individuals in the chronic phase poststroke. Four individuals with chronic stroke (47-65 years old and ≥3 years poststroke), with residual lower extremity impairments (Fugl-Meyer 24-26/34), who were limited community ambulators (gait speed range 0.56-1.1 m/s) participated in this study. Safety was defined as the absence of adverse events. Feasibility was measured using attendance, total exercise time, and "involvement" measured with the presence questionnaire (PQ). Efficacy of CR fitness was evaluated using a submaximal bicycle ergometer test before and after an 8-week training program. The intervention was safe and feasible with participants having 1 adverse event, 100% adherence, achieving between 90 and 125 minutes of cycling each week, and a mean PQ score of 39 (SD 3.3). There was a statistically significant (13%; P = 0.035) improvement in peak VO(2), with a range of 6% to 24.5%. For these individuals, poststroke, VR augmented cycling, using their heart rate to set their avatar's speed, fostered training of sufficient duration and intensity to promote CR fitness. In addition, there was a transfer of training from the bicycle to walking endurance. VR augmented cycling may be an addition to the therapist's tools for concurrent training of mobility and health promotion of individuals poststroke.

Influence of HMB supplementation and resistance training on cytokine responses to resistance exercise.

PubMed

Kraemer, William J; Hatfield, Disa L; Comstock, Brett A; Fragala, Maren S; Davitt, Patrick M; Cortis, Cristina; Wilson, Jacob M; Lee, Elaine C; Newton, Robert U; Dunn-Lewis, Courtenay; Häkkinen, Keijo; Szivak, Tunde K; Hooper, David R; Flanagan, Shawn D; Looney, David P; White, Mark T; Volek, Jeff S; Maresh, Carl M

2014-01-01

The purpose of this study was to determine the effects of a multinutritional supplement including amino acids, β-hydroxy-β-methylbutyrate (HMB), and carbohydrates on cytokine responses to resistance exercise and training. Seventeen healthy, college-aged men were randomly assigned to a Muscle Armor™ (MA; Abbott Nutrition, Columbus, OH) or placebo supplement group and 12 weeks of resistance training. An acute resistance exercise protocol was administered at 0, 6, and 12 weeks of training. Venous blood samples at pre-, immediately post-, and 30-minutes postexercise were analyzed via bead multiplex immunoassay for 17 cytokines. After 12 weeks of training, the MA group exhibited decreased interferon-gamma (IFN-γ) and interleukin (IL)-10. IL-1β differed by group at various times. Granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, IL-7, IL-8, IL-12p70, IL-13, IL-17, monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1β) changed over the 12-week training period but did not differ by group. Twelve weeks of resistance training alters the cytokine response to acute resistance exercise, and supplementation with HMB and amino acids appears to further augment this result.

Effects of whole-body vibration applied to lower extremity muscles during decline bench press exercise.

PubMed

García-Gutiérrez, M T; Hazell, T J; Marín, P J

2016-09-07

To evaluate the effects of whole-body vibration (WBV) on skeletal muscle activity and power performance of the upper body during decline bench press exercise at different loads. Forty-seven healthy young and active male students volunteered. Each performed dynamic decline bench press repetitions with and without WBV (50 Hz, 2.2 mm) applied through a hamstring bridge exercise at three different loads of their 1-repetition maximum (1RM): 30%, 50%, and 70% 1RM. Muscle activity of the triceps brachii (TB), biceps brachii (BB), pectoralis major (PM), and biceps femoris (BF) was measured with surface electromyography electrodes and kinetic parameters of the repetitions were measured with a rotary encoder. WBV increased peak power (PP) output during the 70% 1RM condition (p<0.01). Muscle activity was increased with WBV in the TB and BF muscles at all loads (p<0.05). There were no effects of WBV on BB or PM muscles. WBV applied through a hamstring bridge exercise increases TB muscle activity during a decline bench press and this augmentation contributes to an increased peak power at higher loads and increased peak acceleration at lower loads.

Respiratory Motion-Resolved Compressed Sensing Reconstruction of Free-Breathing Radial Acquisition for Dynamic Liver Magnetic Resonance Imaging.

PubMed

Chandarana, Hersh; Feng, Li; Ream, Justin; Wang, Annie; Babb, James S; Block, Kai Tobias; Sodickson, Daniel K; Otazo, Ricardo

2015-11-01

This study aimed to demonstrate feasibility of free-breathing radial acquisition with respiratory motion-resolved compressed sensing reconstruction [extra-dimensional golden-angle radial sparse parallel imaging (XD-GRASP)] for multiphase dynamic gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced liver imaging, and to compare image quality to compressed sensing reconstruction with respiratory motion-averaging (GRASP) and prior conventional breath-held Cartesian-sampled data sets [BH volume interpolated breath-hold examination (VIBE)] in same patients. In this Health Insurance Portability and Accountability Act-compliant prospective study, 16 subjects underwent free-breathing continuous radial acquisition during Gd-EOB-DTPA injection and had prior BH-VIBE available. Acquired data were reconstructed using motion-averaging GRASP approach in which consecutive 84 spokes were grouped in each contrast-enhanced phase for a temporal resolution of approximately 14 seconds. Additionally, respiratory motion-resolved reconstruction was performed from the same k-space data by sorting each contrast-enhanced phase into multiple respiratory motion states using compressed sensing algorithm named XD-GRASP, which exploits sparsity along both the contrast-enhancement and respiratory-state dimensions.Contrast-enhanced dynamic multiphase XD-GRASP, GRASP, and BH-VIBE images were anonymized, pooled together in a random order, and presented to 2 board-certified radiologists for independent evaluation of image quality, with higher score indicating more optimal examination. The XD-GRASP reconstructions had significantly (all P < 0.05) higher overall image quality scores compared to GRASP for early arterial (reader 1: 4.3 ± 0.6 vs 3.31 ± 0.6; reader 2: 3.81 ± 0.8 vs 3.38 ± 0.9) and late arterial (reader 1: 4.5 ± 0.6 vs 3.63 ± 0.6; reader 2: 3.56 ± 0.5 vs 2.88 ± 0.7) phases of enhancement for both readers. The XD-GRASP also had higher overall image quality score in portal venous phase, which was significant for reader 1 (4.44 ± 0.5 vs 3.75 ± 0.8; P = 0.002). In addition, the XD-GRASP had higher overall image quality score compared to BH-VIBE for early (reader 1: 4.3 ± 0.6 vs 3.88 ± 0.6; reader 2: 3.81 ± 0.8 vs 3.50 ± 1.0) and late (reader 1: 4.5 ± 0.6 vs 3.44 ± 0.6; reader 2: 3.56 ± 0.5 vs 2.94 ± 0.9) arterial phases. Free-breathing motion-resolved XD-GRASP reconstructions provide diagnostic high-quality multiphase images in patients undergoing Gd-EOB-DTPA-enhanced liver examination.

Acute exercise and motor memory consolidation: Does exercise type play a role?

PubMed

Thomas, R; Flindtgaard, M; Skriver, K; Geertsen, S S; Christiansen, L; Korsgaard Johnsen, L; Busk, D V P; Bojsen-Møller, E; Madsen, M J; Ritz, C; Roig, M; Lundbye-Jensen, J

2017-11-01

A single bout of high-intensity exercise can augment off-line gains in skills acquired during motor practice. It is currently unknown if the type of physical exercise influences the effect on motor skill consolidation. This study investigated the effect of three types of high-intensity exercise following visuomotor skill acquisition on the retention of motor memory in 40 young (25.3 ±3.6 years), able-bodied male participants randomly assigned to one of four groups either performing strength training (STR), circuit training (CT), indoor hockey (HOC) or rest (CON). Retention tests of the motor skill were performed 1 (R1h) and 24 h (R1d) post acquisition. For all exercise groups, mean motor performance scores decreased at R1h compared to post acquisition (POST) level; STR (P = 0.018), CT (P = 0.02), HOC (P = 0.014) and performance scores decreased for CT compared to CON (P = 0.049). Mean performance scores increased from POST to R1d for all exercise groups; STR (P = 0.010), CT (P = 0.020), HOC (P = 0.007) while performance scores for CON decreased (P = 0.043). Changes in motor performance were thus greater for STR (P = 0.006), CT (P < 0.001) and HOC (P < 0.001) compared to CON from POST to R1d. The results demonstrate that high-intensity, acute exercise can lead to a decrease in motor performance assessed shortly after motor skill practice (R1h), but enhances offline effects promoting long-term retention (R1d). Given that different exercise modalities produced similar positive off-line effects on motor memory, we conclude that exercise-induced effects beneficial to consolidation appear to depend primarily on the physiological stimulus rather than type of exercise and movements employed. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Improving Grasp Skills Using Schema Structured Learning

NASA Technical Reports Server (NTRS)

Platt, Robert; Grupen, ROderic A.; Fagg, Andrew H.

2006-01-01

Abstract In the control-based approach to robotics, complex behavior is created by sequencing and combining control primitives. While it is desirable for the robot to autonomously learn the correct control sequence, searching through the large number of potential solutions can be time consuming. This paper constrains this search to variations of a generalized solution encoded in a framework known as an action schema. A new algorithm, SCHEMA STRUCTURED LEARNING, is proposed that repeatedly executes variations of the generalized solution in search of instantiations that satisfy action schema objectives. This approach is tested in a grasping task where Dexter, the UMass humanoid robot, learns which reaching and grasping controllers maximize the probability of grasp success.

Neuron Specific Rab4 Effector GRASP-1 Coordinates Membrane Specialization and Maturation of Recycling Endosomes

PubMed Central

Hoogenraad, Casper C.; Popa, Ioana; Futai, Kensuke; Sanchez-Martinez, Emma; Wulf, Phebe S.; van Vlijmen, Thijs; Dortland, Bjorn R.; Oorschot, Viola; Govers, Roland; Monti, Maria; Heck, Albert J. R.; Sheng, Morgan; Klumperman, Judith; Rehmann, Holger; Jaarsma, Dick; Kapitein, Lukas C.; van der Sluijs, Peter

2010-01-01

The endosomal pathway in neuronal dendrites is essential for membrane receptor trafficking and proper synaptic function and plasticity. However, the molecular mechanisms that organize specific endocytic trafficking routes are poorly understood. Here, we identify GRIP-associated protein-1 (GRASP-1) as a neuron-specific effector of Rab4 and key component of the molecular machinery that coordinates recycling endosome maturation in dendrites. We show that GRASP-1 is necessary for AMPA receptor recycling, maintenance of spine morphology, and synaptic plasticity. At the molecular level, GRASP-1 segregates Rab4 from EEA1/Neep21/Rab5-positive early endosomal membranes and coordinates the coupling to Rab11-labelled recycling endosomes by interacting with the endosomal SNARE syntaxin 13. We propose that GRASP-1 connects early and late recycling endosomal compartments by forming a molecular bridge between Rab-specific membrane domains and the endosomal SNARE machinery. The data uncover a new mechanism to achieve specificity and directionality in neuronal membrane receptor trafficking. PMID:20098723

A hybrid system for upper limb movement restoration in quadriplegics.

PubMed

Varoto, Renato; Barbarini, Elisa Signoreto; Cliquet, Alberto

2008-09-01

Generally, quadriplegic individuals have difficulties performing object manipulation. Toward satisfactory manipulation, reach and grasp movements must be performed with voluntary control, and for that, grasp force feedback is essential. A hybrid system aiming at partial upper limb sensory-motor restoration for quadriplegics was built. Such device is composed of an elbow dynamic orthosis that provides elbow flexion/extension (range was approximately from 20 degrees to 120 degrees , and average angular speed was approximately 15 degrees /s) with forearm support, a wrist static orthosis and neuromuscular electrical stimulation for grasping generation, and a glove with force sensors that allows grasping force feedback. The glove presents two user interface modes: visual by light emitting diodes or audio emitted by buzzer. Voice control of the entire system (elbow dynamic orthosis and electrical stimulator) is performed by the patient. The movements provided by the hybrid system, combined with the scapular and shoulder movements performed by the patient, can aid quadriplegic individuals in tasks that involve reach and grasp movements.

Electrotactile Feedback Improves Performance and Facilitates Learning in the Routine Grasping Task.

PubMed

Isaković, Milica; Belić, Minja; Štrbac, Matija; Popović, Igor; Došen, Strahinja; Farina, Dario; Keller, Thierry

2016-06-13

Aim of this study was to investigate the feasibility of electrotactile feedback in closed loop training of force control during the routine grasping task. The feedback was provided using an array electrode and a simple six-level spatial coding, and the experiment was conducted in three amputee subjects. The psychometric tests confirmed that the subjects could perceive and interpret the electrotactile feedback with a high success rate. The subjects performed the routine grasping task comprising 4 blocks of 60 grasping trials. In each trial, the subjects employed feedforward control to close the hand and produce the desired grasping force (four levels). First (baseline) and the last (validation) session were performed in open loop, while the second and the third session (training) included electrotactile feedback. The obtained results confirmed that using the feedback improved the accuracy and precision of the force control. In addition, the subjects performed significantly better in the validation vs. baseline session, therefore suggesting that electrotactile feedback can be used for learning and training of myoelectric control.

Goal-Directed Grasping: The Dimensional Properties of an Object Influence the Nature of the Visual Information Mediating Aperture Shaping

ERIC Educational Resources Information Center

Holmes, Scott A.; Heath, Matthew

2013-01-01

An issue of continued debate in the visuomotor control literature surrounds whether a 2D object serves as a representative proxy for a 3D object in understanding the nature of the visual information supporting grasping control. In an effort to reconcile this issue, we examined the extent to which aperture profiles for grasping 2D and 3D objects…

Decoding 3-D Reach and Grasp Kinematics from High-Frequency Local Field Potentials in Primate Primary Motor Cortex

PubMed Central

Zhuang, Jun; Vargas-Irwin, Carlos; Donoghue, John P.

2011-01-01

Intracortical microelectrode array recordings generate a variety of neural signals with potential application as control signals in neural interface systems. Previous studies have focused on single and multiunit activity, as well as low frequency local field potentials (LFPs), but have not explored higher frequency (>200 Hz) LFPs. In addition, the potential to decode three dimensional (3-D) reach and grasp kinematics based on LFPs has not been demonstrated. Here, we use mutual information and decoding analyses to probe the information content about 3-D reaching and grasping of 7 different LFP frequency bands in the range of 0.3 Hz – 400 Hz. LFPs were recorded via 96-microelectrode arrays in primary motor cortex (M1) of two monkeys performing free reaching to grasp moving objects. Mutual information analyses revealed that higher frequency bands (e.g. 100 – 200 Hz and 200 – 400 Hz) carried the most information about the examined kinematics. Furthermore, Kalman filter decoding revealed that broadband high frequency LFPs, likely reflecting multiunit activity, provided the best decoding performance as well as substantial accuracy in reconstructing reach kinematics, grasp aperture and aperture velocity. These results indicate that LFPs, especially high frequency bands, could be useful signals for neural interfaces controlling 3-D reach and grasp kinematics. PMID:20403782

The Wire-Grasping Method as a New Technique for Forceps Biopsy of Biliary Strictures: A Prospective Randomized Controlled Study of Effectiveness.

PubMed

Yamashita, Yasunobu; Ueda, Kazuki; Kawaji, Yuki; Tamura, Takashi; Itonaga, Masahiro; Yoshida, Takeichi; Maeda, Hiroki; Magari, Hirohito; Maekita, Takao; Iguchi, Mikitaka; Tamai, Hideyuki; Ichinose, Masao; Kato, Jun

2016-07-15

Transpapillary forceps biopsy is an effective diagnostic technique in patients with biliary stricture. This prospective study aimed to determine the usefulness of the wire-grasping method as a new technique for forceps biopsy. Consecutive patients with biliary stricture or irregularities of the bile duct wall were randomly allocated to either the direct or wire-grasping method group. In the wiregrasping method, forceps in the duodenum grasps a guidewire placed into the bile duct beforehand, and then, the forceps are pushed through the papilla without endoscopic sphincterotomy. In the direct method, forceps are directly pushed into the bile duct alongside a guide-wire. The primary endpoint was the success rate of obtaining specimens suitable for adequate pathological examination. In total, 32 patients were enrolled, and 28 (14 in each group) were eligible for analysis. The success rate was significantly higher using the wire-grasping method than the direct method (100% vs 50%, p=0.016). Sensitivity and accuracy for the diagnosis of cancer were comparable in patients with the successful procurement of biopsy specimens between the two methods (91% vs 83% and 93% vs 86%, respectively). The wire-grasping method is useful for diagnosing patients with biliary stricture or irregularities of the bile duct wall.

Reliable vision-guided grasping

NASA Technical Reports Server (NTRS)

Nicewarner, Keith E.; Kelley, Robert B.

1992-01-01

Automated assembly of truss structures in space requires vision-guided servoing for grasping a strut when its position and orientation are uncertain. This paper presents a methodology for efficient and robust vision-guided robot grasping alignment. The vision-guided grasping problem is related to vision-guided 'docking' problems. It differs from other hand-in-eye visual servoing problems, such as tracking, in that the distance from the target is a relevant servo parameter. The methodology described in this paper is hierarchy of levels in which the vision/robot interface is decreasingly 'intelligent,' and increasingly fast. Speed is achieved primarily by information reduction. This reduction exploits the use of region-of-interest windows in the image plane and feature motion prediction. These reductions invariably require stringent assumptions about the image. Therefore, at a higher level, these assumptions are verified using slower, more reliable methods. This hierarchy provides for robust error recovery in that when a lower-level routine fails, the next-higher routine will be called and so on. A working system is described which visually aligns a robot to grasp a cylindrical strut. The system uses a single camera mounted on the end effector of a robot and requires only crude calibration parameters. The grasping procedure is fast and reliable, with a multi-level error recovery system.

Observation-based training for neuroprosthetic control of grasping by amputees.

PubMed

Agashe, Harshavardhan A; Contreras-Vidal, Jose L

2014-01-01

Current brain-machine interfaces (BMIs) allow upper limb amputees to position robotic arms with a high degree of accuracy, but lack the ability to control hand pre-shaping for grasping different objects. We have previously shown that low frequency (0.1-1 Hz) time domain cortical activity recorded at the scalp via electroencephalography (EEG) encodes information about grasp pre-shaping. To transfer this technology to clinical populations such as amputees, the challenge lies in constructing BMI models in the absence of overt training hand movements. Here we show that it is possible to train BMI models using observed grasping movements performed by a robotic hand attached to amputees' residual limb. Three transradial amputees controlled the grasping motion of an attached robotic hand via their EEG, following the action-observation training phase. Over multiple sessions, subjects successfully grasped the presented object (a bottle or a credit card) in 53±16 % of trials, demonstrating the validity of the BMI models. Importantly, the validation of the BMI model was through closed-loop performance, which demonstrates generalization of the model to unseen data. These results suggest `mirror neuron system' properties captured by delta band EEG that allows neural representation for action observation to be used for action control in an EEG-based BMI system.

The syntactic organization of pasta-eating and the structure of reach movements in the head-fixed mouse.

PubMed

Whishaw, Ian Q; Faraji, Jamshid; Kuntz, Jessica R; Mirza Agha, Behroo; Metz, Gerlinde A S; Mohajerani, Majid H

2017-09-08

Mice are adept in the use of their hands for activities such as feeding, which has led to their use in investigations of the neural basis of skilled-movements. We describe the syntactic organization of pasta-eating and the structure of hand movements used for pasta manipulation by the head-fixed mouse. An ethogram of mice consuming pieces of spaghetti reveals that they eat in bite/chew bouts. A bout begins with pasta lifted to the mouth and then manipulated with hand movements into a preferred orientation for biting. Manipulation involves many hand release-reach movements, each with a similar structure. A hand is advanced from a digit closed and flexed (collect) position to a digit extended and open position (overgrasp) and then to a digit closed and flexed (grasp) position. Reach distance, hand shaping, and grasp patterns featuring precision grasps or whole hand grasps are related. To bite, mice display hand preference and asymmetric grasps; one hand (guide grasp) directs food into the mouth and the other stabilizes the pasta for biting. When chewing after biting, the hands hold the pasta in a symmetric resting position. Pasta-eating is organized and features structured hand movements and so lends itself to the neural investigation of skilled-movements.

Effects of object shape on the visual guidance of action.

PubMed

Eloka, Owino; Franz, Volker H

2011-04-22

Little is known of how visual coding of the shape of an object affects grasping movements. We addressed this issue by investigating the influence of shape perturbations on grasping. Twenty-six participants grasped a disc or a bar that were chosen such that they could in principle be grasped with identical movements (i.e., relevant sizes were identical such that the final grips consisted of identical separations of the fingers and no parts of the objects constituted obstacles for the movement). Nevertheless, participants took object shape into account and grasped the bar with a larger maximum grip aperture and a different hand angle than the disc. In 20% of the trials, the object changed its shape from bar to disc or vice versa early or late during the movement. If there was enough time (early perturbations), grasps were often adapted in flight to the new shape. These results show that the motor system takes into account even small and seemingly irrelevant changes of object shape and adapts the movement in a fine-grained manner. Although this adaptation might seem computationally expensive, we presume that its benefits (e.g., a more comfortable and more accurate movement) outweigh the costs. Copyright © 2011 Elsevier Ltd. All rights reserved.

Post-exercise ingestion of a unique, high molecular weight glucose polymer solution improves performance during a subsequent bout of cycling exercise.

PubMed

Stephens, Francis B; Roig, Marc; Armstrong, Gerald; Greenhaff, Paul L

2008-01-15

The aim of the present study was to determine the effect of post-exercise ingestion of a unique, high molecular weight glucose polymer solution, known to augment gastric emptying and post-exercise muscle glycogen re-synthesis, on performance during a subsequent bout of intense exercise. On three randomized visits, eight healthy men cycled to exhaustion at 73.0% (s = 1.3) maximal oxygen uptake (90 min, s = 15). Immediately after this, participants consumed a one-litre solution containing sugar-free flavoured water (control), 100 g of a low molecular weight glucose polymer or 100 g of a very high molecular weight glucose polymer, and rested on a bed for 2 h. After recovery, a 15-min time-trial was performed on a cycle ergometer, during which work output was determined. Post-exercise ingestion of the very high molecular weight glucose polymer solution resulted in faster and greater increases in blood glucose (P < 0.001) and serum insulin (P < 0.01) concentrations than the low molecular weight glucose polymer solution, and greater work output during the 15-min time-trial (164.1 kJ, s = 21.1) than both the sugar-free flavoured water (137.5 kJ, s = 24.2; P < 0.05) and the low molecular weight glucose polymer (149.4 kJ, s = 21.8; P < 0.05) solutions. These findings could be of practical importance for athletes wishing to optimize performance by facilitating rapid re-synthesis of the muscle glycogen store during recovery following prolonged sub-maximal exercise.

Augmented sympathetic vasoconstriction in exercising forearms of postmenopausal women is reversed by oestrogen therapy

PubMed Central

Fadel, Paul J; Wang, Zhongyun; Watanabe, Hitoshi; Arbique, Debbie; Vongpatanasin, Wanpen; Thomas, Gail D

2004-01-01

Sympathetic vasoconstriction is normally attenuated in exercising muscles of young men and women. Recent evidence indicates that such modulation, termed functional sympatholysis, may be impaired in older men. Whether a similar impairment occurs in older women, and what role oestrogen deficiency might play in this impairment, are not known. Based on the strong positive correlation between circulating oestrogen levels and functional sympatholysis previously reported in female rats, we hypothesized that sympatholysis would be impaired in oestrogen-deficient postmenopausal women, and that this impairment would be reversed by oestrogen replacement. To test these hypotheses, we measured vasoconstrictor responses in the forearms of pre- and postmenopausal women using near infrared spectroscopy to detect decreases in muscle oxygenation in response to reflex activation of sympathetic nerves evoked by lower body negative pressure (LBNP). In eight premenopausal women, LBNP decreased muscle oxygenation by 20 ± 1% in resting forearm, but only by 3 ± 2% in exercising forearm (P < 0.05). In contrast, in eight postmenopausal women, LBNP decreased muscle oxygenation by 15 ± 3% in resting forearm, and by 12 ± 4% in exercising forearm (P > 0.05). After 1 month of transdermal oestradiol replacement in these women, the normal effect of exercise to blunt sympathetic vasoconstriction was restored (rest, −19 ± 3%; exercise, −2 ± 3%; P < 0.05). These data indicate that functional sympatholysis is impaired in oestrogen-deficient postmenopausal women. The effect of short-term unopposed oestrogen replacement to correct this impairment implicates a role for oestrogen in the sympathetic neural control of muscle haemodynamics during exercise. PMID:15498809

Methamphetamine blocks exercise effects on Bdnf and Drd2 gene expression in frontal cortex and striatum.

PubMed

Thompson, Andrew B; Stolyarova, Alexandra; Ying, Zhe; Zhuang, Yumei; Gómez-Pinilla, Fernando; Izquierdo, Alicia

2015-12-01

Exposure to drugs of abuse can produce many neurobiological changes which may lead to increased valuation of rewards and decreased sensitivity to their costs. Many of these behavioral alterations are associated with activity of D2-expressing medium spiny neurons in the striatum. Additionally, Bdnf in the striatum has been shown to play a role in flexible reward-seeking behavior. Given that voluntary aerobic exercise can affect the expression of these proteins in healthy subjects, and that exercise has shown promise as an anti-addictive therapy, we set out to quantify changes in D2 and Bdnf expression in methamphetamine-exposed rats given access to running wheels. Sixty-four rats were treated for two weeks with an escalating dose of methamphetamine or saline, then either sacrificed, housed in standard cages, or given free access to a running wheel for 6 weeks prior to sacrifice. Rats treated with methamphetamine ran significantly greater distances than saline-treated rats, suggesting an augmentation in the reinforcement value of voluntary wheel running. Transcription of Drd2 and Bdnf was assessed via RT-qPCR. Protein expression levels of D2 and phosphorylation of the TrkB receptor were measured via western blot. Drd2 and Bdnf mRNA levels were impacted independently by exercise and methamphetamine, but exposure to methamphetamine prior to the initiation of exercise blocked the exercise-induced changes seen in rats treated with saline. Expression levels of both proteins were elevated immediately after methamphetamine, but returned to baseline after six weeks, regardless of exercise status. Copyright © 2015 Elsevier Ltd. All rights reserved.