Effect of Transducer Orientation on Errors in Ultrasound Image-Based Measurements of Human Medial Gastrocnemius Muscle Fascicle Length and Pennation.

PubMed

Bolsterlee, Bart; Gandevia, Simon C; Herbert, Robert D

2016-01-01

Ultrasound imaging is often used to measure muscle fascicle lengths and pennation angles in human muscles in vivo. Theoretically the most accurate measurements are made when the transducer is oriented so that the image plane aligns with muscle fascicles and, for measurements of pennation, when the image plane also intersects the aponeuroses perpendicularly. However this orientation is difficult to achieve and usually there is some degree of misalignment. Here, we used simulated ultrasound images based on three-dimensional models of the human medial gastrocnemius, derived from magnetic resonance and diffusion tensor images, to describe the relationship between transducer orientation and measurement errors. With the transducer oriented perpendicular to the surface of the leg, the error in measurement of fascicle lengths was about 0.4 mm per degree of misalignment of the ultrasound image with the muscle fascicles. If the transducer is then tipped by 20°, the error increases to 1.1 mm per degree of misalignment. For a given degree of misalignment of muscle fascicles with the image plane, the smallest absolute error in fascicle length measurements occurs when the transducer is held perpendicular to the surface of the leg. Misalignment of the transducer with the fascicles may cause fascicle length measurements to be underestimated or overestimated. Contrary to widely held beliefs, it is shown that pennation angles are always overestimated if the image is not perpendicular to the aponeurosis, even when the image is perfectly aligned with the fascicles. An analytical explanation is provided for this finding.

Ultrasound of skeletal muscle injury.

PubMed

Koh, Eamon Su Chun; McNally, Eugene G

2007-06-01

The professional and recreational demands of modern society make the treatment of muscle injury an increasingly important clinical problem, particularly in the athletic population. In the elite athlete, significant financial and professional pressures may also exist that emphasize the need for accurate diagnosis and treatment. With new advances in ultrasound technology, images of exquisite detail allow diagnosis of muscle injury that matches the accuracy of magnetic resonance imaging (MRI). Furthermore, the benefits of real-time and Doppler imaging, ability to perform interventional procedures, and relative cost benefits compared with MRI place ultrasound at the forefront for investigation for these injuries in many circumstances. Muscle injury may be divided into acute and chronic pathology, with muscle strain injury the most common clinical problem presenting to sports physicians. This article reviews the spectrum of acute and chronic muscle injuries, with particular attention to clinical features and some common or important muscle strain injuries.

Functional aspects of cross-legged sitting with special attention to piriformis muscles and sacroiliac joints.

PubMed

Snijders, Chris J; Hermans, Paul F G; Kleinrensink, Gerrit Jan

2006-02-01

Transversely oriented pelvic muscles such as the internal abdominal oblique, transversus abdominis, piriformis and pelvic floor muscles may contribute to sacroiliac joint stability by pressing the sacrum between the hipbones. Surface electromyographic measurements showed that leg crossing lowers the activity of the internal oblique abdominal muscle significantly. This suggests that leg crossing is a substitute for abdominal muscle activity. No previous studies addressed piriformis muscle and related pelvic structures in cross-legged sitting. Angles of pelvis and femur were measured in healthy subjects in standing, normal sitting and cross-legged sitting, and were used to simulate these postures on embalmed pelvises and measure piriformis muscle elongation. Deformations of pelvic ring and iliolumbar ligament caused by piriformis muscle force were measured on embalmed pelvises. Cross-legged sitting resulted in a relative elongation of the piriformis muscle of 11.7% compared to normal sitting and even 21.4% compared to standing. Application of piriformis muscle force resulted in inward deformation of the pelvic ring and compression of the sacroiliac joints and the dorsal side of the pubic symphysis. Cross-legged sitting is common. We believe that it contributes to sacroiliac joint stability. This study demonstrates the influence of the piriformis muscle on sacroiliac joint compression. The elongation of the piriformis muscle bilaterally by crossing the legs may be functional in the build-up of active or passive tension between sacrum and femur.

The difference in passive tension applied to the muscles composing the hamstrings - Comparison among muscles using ultrasound shear wave elastography.

PubMed

Nakamura, Masatoshi; Hasegawa, Satoshi; Umegaki, Hiroki; Nishishita, Satoru; Kobayashi, Takuya; Fujita, Kosuke; Tanaka, Hiroki; Ibuki, Satoko; Ichihashi, Noriaki

2016-08-01

Hamstring muscle strain is one of the most common injuries in sports. Therefore, to investigate the factors influencing hamstring strain, the differences in passive tension applied to the hamstring muscles at the same knee and hip positions as during terminal swing phase would be useful information. In addition, passive tension applied to the hamstrings could change with anterior or posterior tilt of the pelvis. The aims of this study were to investigate the difference in passive tension applied to the individual muscles composing the hamstrings during passive elongation, and to investigate the effect of pelvic position on passive tension. Fifteen healthy men volunteered for this study. The subject lay supine with the angle of the trunk axis to the femur of their dominant leg at 70° and the knee angle of the dominant leg fixed at 30° flexion. In three pelvic positions ("Non-Tilt", "Anterior-Tilt" and "Posterior-Tilt"), the shear elastic modulus of each muscle composing the hamstrings (semitendinosus, semimembranosus, and biceps femoris) was measured using an ultrasound shear wave elastography. The shear elastic modulus of semimembranosus was significantly higher than the others. Shear elastic modulus of the hamstrings in Anterior-Tilt was significantly higher than in Posterior-Tilt. Passive tension applied to semimembranosus is higher than the other muscles when the hamstring muscle is passively elongated, and passive tension applied to the hamstrings increases with anterior tilt of the pelvis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prevention of metabolic alterations caused by suspension hypokinesia in leg muscles of rats

NASA Technical Reports Server (NTRS)

Tischler, M. E.; Jaspers, S. R.; Fagan, J. M.

1983-01-01

Rats were subjected to tail-cast suspension hypokinesia for 6 days with one leg immobilized in dorsal flexion by casting. Control animals were also tail-casted. The soleus, gastrocnemius and plantaris muscles of uncasted hypokinetic legs were smaller than control muscles. Dorsal flexion prevented atrophy of these muscles and caused the soleus to hypertrophy. The anterior muscles were unaffected by hypokinesia. The smaller size of the soleus of the uncasted leg relative to the dorsal flexed and weight bearing limbs correlated with slower protein synthesis and faster proteolysis. The capacity of this muscle to synthesize glutamine (gln), which carries nitrogenous waste from muscle was also measured. Although tissue homogenates showed higher activities of gln synthetase, the rate of de novo synthesis was not altered in intact muscle but the tissue ratio of gln/glutamate was decreased. Glutamate and ATP were not limiting for gln synthesis, but availability of ammonia may be a limiting factor for this process in hypokinesia.

The control of mono-articular muscles in multijoint leg extensions in man.

PubMed Central

van Ingen Schenau, G J; Dorssers, W M; Welter, T G; Beelen, A; de Groot, G; Jacobs, R

1995-01-01

1. Movements often require control of direction and a magnitude of force exerted externally on the environment. Bi-articular upper leg muscles appear to play a unique role in the regulation of the net torques about the hip and knee joints, necessary for the control of this external force. 2. The aim of this study was to test the hypothesis that the mono-articular muscles act as work generators in powerful dynamic leg extensions, which means that they should be activated primarily in the phases during which they can contribute to work, irrespective of the net joint torques required to control the external force. 3. Cycling movements of six trained subjects were analysed by means of inverse dynamics, yielding net joint torques as well as activity patterns and shortening velocities of four mono- and four bi-articular leg muscles. 4. The results show that the mono-articular muscles exert force only in the phase in which these muscles shorten, whereas this appears not to be the case for the bi-articular muscles. 5. Reciprocal patterns of activation of the rectus femoris and hamstring muscles appear to tune the distribution of net joint torques about the hip and knee joints, necessary to control the (changing) direction of the force on the pedal. 6. An analysis of running in man and additional related literature based on animal studies appears to provide further support for the hypothesis that mono- and bi-articular muscles have essentially different roles in these powerful multijoint leg extension tasks. PMID:7602524

A system for evaluation and exercise-conditioning of paralyzed leg muscles.

PubMed

Gruner, J A; Glaser, R M; Feinberg, S D; Collins, S R; Nussbaum, N S

1983-07-01

The purpose of this project was to develop instrumentation and protocols in which electrical stimulation is used to induce exercise in paralyzed quadriceps muscles strength and endurance evaluation and conditioning. A computer-controlled electrical stimulation system, using surface electrodes, automatically regulates the bouts of leg extension exercise. Load weights attached just above the ankles can be progressively increased over a number of training sessions in such a manner that a measure of the fitness of the legs can be obtained. With three exercise sessions per week for 9 weeks, the strength and endurance of the quadriceps muscles of two paraplegic and four quadriplegic subjects were gradually and safely increased. During exercise at a means load weight of 5.4 kg, means heart rate did not rise above rest, whereas systolic blood pressure increased about 20 mm Hg, and skin temperature above the active muscles increased about 1.75 degrees C. Such exercise conditioning appears to be safe and may provide important health benefits, including improved fitness of the muscles and bones, better circulation in the paralyzed limbs, and enhanced self-image. Conditioned electrically stimulated paralyzed leg muscles may be used for locomotion in conjunction with special vehicles.

A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

PubMed

Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Bin Aziz, Mohamed Fareez; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M; Sato, Hirotaka

2014-01-01

In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot).

Quantitative muscle ultrasound and quadriceps strength in patients with post-polio syndrome.

PubMed

Bickerstaffe, Alice; Beelen, Anita; Zwarts, Machiel J; Nollet, Frans; van Dijk, Johannes P

2015-01-01

We investigated whether muscle ultrasound can distinguish muscles affected by post-polio syndrome (PPS) from healthy muscles and whether severity of ultrasound abnormalities is associated with muscle strength. Echo intensity, muscle thickness, and isometric strength of the quadriceps muscles were measured in 48 patients with PPS and 12 healthy controls. Patients with PPS had significantly higher echo intensity and lower muscle thickness than healthy controls. In patients, both echo intensity and muscle thickness were associated independently with muscle strength. A combined measure of echo intensity and muscle thickness was more strongly related to muscle strength than either parameter alone. Quantitative ultrasound distinguishes healthy muscles from those affected by PPS, and measures of muscle quality and quantity are associated with muscle strength. Hence, ultrasound could be a useful tool for assessing disease severity and monitoring changes resulting from disease progression or clinical intervention in patients with PPS. © 2014 Wiley Periodicals, Inc.

Control of Leg Movements Driven by EMG Activity of Shoulder Muscles

PubMed Central

La Scaleia, Valentina; Sylos-Labini, Francesca; Hoellinger, Thomas; Wang, Letian; Cheron, Guy; Lacquaniti, Francesco; Ivanenko, Yuri P.

2014-01-01

During human walking, there exists a functional neural coupling between arms and legs, and between cervical and lumbosacral pattern generators. Here, we present a novel approach for associating the electromyographic (EMG) activity from upper limb muscles with leg kinematics. Our methodology takes advantage of the high involvement of shoulder muscles in most locomotor-related movements and of the natural co-ordination between arms and legs. Nine healthy subjects were asked to walk at different constant and variable speeds (3–5 km/h), while EMG activity of shoulder (deltoid) muscles and the kinematics of walking were recorded. To ensure a high level of EMG activity in deltoid, the subjects performed slightly larger arm swinging than they usually do. The temporal structure of the burst-like EMG activity was used to predict the spatiotemporal kinematic pattern of the forthcoming step. A comparison of actual and predicted stride leg kinematics showed a high degree of correspondence (r > 0.9). This algorithm has been also implemented in pilot experiments for controlling avatar walking in a virtual reality setup and an exoskeleton during over-ground stepping. The proposed approach may have important implications for the design of human–machine interfaces and neuroprosthetic technologies such as those of assistive lower limb exoskeletons. PMID:25368569

Control of Leg Movements Driven by EMG Activity of Shoulder Muscles.

PubMed

La Scaleia, Valentina; Sylos-Labini, Francesca; Hoellinger, Thomas; Wang, Letian; Cheron, Guy; Lacquaniti, Francesco; Ivanenko, Yuri P

2014-01-01

During human walking, there exists a functional neural coupling between arms and legs, and between cervical and lumbosacral pattern generators. Here, we present a novel approach for associating the electromyographic (EMG) activity from upper limb muscles with leg kinematics. Our methodology takes advantage of the high involvement of shoulder muscles in most locomotor-related movements and of the natural co-ordination between arms and legs. Nine healthy subjects were asked to walk at different constant and variable speeds (3-5 km/h), while EMG activity of shoulder (deltoid) muscles and the kinematics of walking were recorded. To ensure a high level of EMG activity in deltoid, the subjects performed slightly larger arm swinging than they usually do. The temporal structure of the burst-like EMG activity was used to predict the spatiotemporal kinematic pattern of the forthcoming step. A comparison of actual and predicted stride leg kinematics showed a high degree of correspondence (r > 0.9). This algorithm has been also implemented in pilot experiments for controlling avatar walking in a virtual reality setup and an exoskeleton during over-ground stepping. The proposed approach may have important implications for the design of human-machine interfaces and neuroprosthetic technologies such as those of assistive lower limb exoskeletons.

Activation Pattern of Lower Leg Muscles in Running on Asphalt, Gravel and Grass.

PubMed

Dolenec, Aleš; Štirn, Igor; Strojnik, Vojko

2015-07-01

Running is performed on different natural surfaces (outdoor) and artificial surfaces (indoor). Different surface characteristics cause modification of the lower leg muscle activation pattern to adopt ankle stiffness to these characteristics. So the purpose of our investigation was to study changes of lower leg muscles activation pattern in running on different natural running surfaces. Six male and two female runners participated. The participants ran at a freely chosen velocity in trials on asphalt while in trials on gravel, and grass surfaces they were attempting to reach similar velocities as in the trials on asphalt. Muscle activation of the peroneus brevis, tibialis anterior, soleus, and gastrocnemius medialis of the right leg was recorded. Running on asphalt increased average EMG amplitude of the m. tibialis anterior in the pre-activation phase and the m. gastrocnemius medialis in the entire contact phase compared to running on grass from 0.222 ± 0.113 V to 0.276 ± 0.136 V and from 0.214 ± 0.084 V to 0.238 ± 0.088 V, respectively. The average EMG of m. peroneus brevis in pre-activation phase increased from 0.156 ± 0.026 V to 0.184 ± 0.455 V in running on grass in comparison to running on gravel. Running on different surfaces is connected with different activation patterns of lower leg muscles. Running on asphalt requires stiff ankle joints, running on gravel requires greater stability in ankle joints, while running on grass is the least demanding on lower leg muscles.

Ultrasound Assessment of the Transverse Abdominis During Functional Movement.

PubMed

Mangum, L Colby; Henderson, Kaitlin; Murray, Kyle P; Saliba, Susan A

2018-05-01

The traditional activation ratio divides contracted muscle thickness by resting muscle thickness while an abdominal draw-in maneuver is performed during hook lying. Ultrasound imaging during function, such as standing or gait, or peak knee flexion in a single-leg squat allows for further visualization of muscle activity. The goal of this study was to examine activation ratio calculations for transverse abdominis function in supine versus loaded conditions to determine the most informative normalization strategy for muscle activity based on thickness values. Transverse abdominis thickness was measured via ultrasound in 35 healthy participants under 4 different conditions. Comparisons were made between the traditional activation ratio tabletop, standing activation ratio (standing abdominal draw-in maneuver thickness/quiet standing thickness), and functional activation ratio (single-leg squat thickness/quiet standing thickness). Additionally, a cued activation ratio (single-leg squat with cued abdominal draw-in maneuver thickness/single-leg squat thickness) during the single-leg squat was obtained. Activation ratios of greater than 1.0 indicated that participants could activate the muscle during activity, and values were compared by analysis of variance. The participants included 23 women and 12 men with a mean age ± SD of 21.3 ± 2.7 years, mass of 66.1 ± 14.4 kg, and height of 168.5 ± 10.1 cm. Activation ratios exceeded 1.0 in 94.3% for the traditional activation ratio, 85.7% for the standing activation ratio, 82.9% for the cued activation ratio, and 82.9% for the functional activation ratio. With groups defined as tabletop activated or not, the standing, cued, and functional activation ratios were all significantly different (all P < .05). Normalizing muscle thickness to the corresponding functional position quiet value provides a useful functional activation ratio and may help clinicians better understand the transverse abdominis role

Ultrasound-Based Detection of Low Muscle Mass for Diagnosis of Sarcopenia in Older Adults.

PubMed

Minetto, Marco A; Caresio, Cristina; Menapace, Tommaso; Hajdarevic, Arnel; Marchini, Andrea; Molinari, Filippo; Maffiuletti, Nicola A

2016-05-01

To establish muscle-specific cut-off values for ultrasound-based detection of low muscle mass, and to assess its prevalence in a population of frail older subjects when applying the cut-points of different muscles and those of different sarcopenic indices. Cross-sectional study. Geriatric outpatient clinic and clinical research laboratory. A total of 44 older adults (30 women and 14 men, mean age 82 years, range 67-93 years) and 60 younger individuals (30 women and 30 men, mean age 26 years, range 20-36 years) participated. Body composition and thickness of 4 lower limb muscles (rectus femoris, vastus lateralis, tibialis anterior, medial gastrocnemius) were respectively assessed by bioelectrical impedance analysis (BIA) and ultrasonography. Site-specific cut-points for ultrasound-based assessment of low muscle mass (muscle thickness values 2 standard deviations below the gender-specific means of our sample of younger subjects) and comparative prevalence rates of low muscle mass. The following site-specific cut-points for muscle thickness were identified: rectus femoris: 20 mm in men and 16 mm in women; vastus lateralis: 17 mm in men and 15 mm in women; tibialis anterior: 23 mm in men and 22 mm in women; and medial gastrocnemius: 13 mm in both men and women. The prevalence of low muscle mass in older adults was highly dependent on the muscle being investigated; it varied from 86% for thigh muscles to 30% for leg muscles. Moreover, the prevalence of low muscle mass was highly dependent on the applied diagnostic criterion and on the adopted cut-off value; it ranged from 2% to 75% for different BIA-derived criteria. We suggest that muscle ultrasonography provides physiatrists with a practical and accurate tool for identifying individuals with low muscle mass. However, the usability of cut-off values established in our group of healthy younger subjects of white ethnicity to identify low muscle mass in older individuals of different ethnic groups remains to be

Real-Time Ultrasound Segmentation, Analysis and Visualisation of Deep Cervical Muscle Structure.

PubMed

Cunningham, Ryan J; Harding, Peter J; Loram, Ian D

2017-02-01

Despite widespread availability of ultrasound and a need for personalised muscle diagnosis (neck/back pain-injury, work related disorder, myopathies, neuropathies), robust, online segmentation of muscles within complex groups remains unsolved by existing methods. For example, Cervical Dystonia (CD) is a prevalent neurological condition causing painful spasticity in one or multiple muscles in the cervical muscle system. Clinicians currently have no method for targeting/monitoring treatment of deep muscles. Automated methods of muscle segmentation would enable clinicians to study, target, and monitor the deep cervical muscles via ultrasound. We have developed a method for segmenting five bilateral cervical muscles and the spine via ultrasound alone, in real-time. Magnetic Resonance Imaging (MRI) and ultrasound data were collected from 22 participants (age: 29.0±6.6, male: 12). To acquire ultrasound muscle segment labels, a novel multimodal registration method was developed, involving MRI image annotation, and shape registration to MRI-matched ultrasound images, via approximation of the tissue deformation. We then applied polynomial regression to transform our annotations and textures into a mean space, before using shape statistics to generate a texture-to-shape dictionary. For segmentation, test images were compared to dictionary textures giving an initial segmentation, and then we used a customized Active Shape Model to refine the fit. Using ultrasound alone, on unseen participants, our technique currently segments a single image in [Formula: see text] to over 86% accuracy (Jaccard index). We propose this approach is applicable generally to segment, extrapolate and visualise deep muscle structure, and analyse statistical features online.

Relationship between leg extensor muscle strength and knee joint loading during gait before and after total knee arthroplasty.

PubMed

Vahtrik, Doris; Gapeyeva, Helena; Ereline, Jaan; Pääsuke, Mati

2014-01-01

The aim of the present study was to evaluate an isometric maximal voluntary contraction (MVC) force of the leg extensor muscles and its relationship with knee joint loading during gait prior and after total knee arthroplasty (TKA). Custom-made dynamometer was used to assess an isometric MVC force of the leg extensor muscles and 3-D motion analysis system was used to evaluate the knee joint loading during gait in 13 female patients (aged 49-68 years) with knee osteoarthritis. Patients were evaluated one day before, and three and six months following TKA in the operated and non-operated leg. Six months after TKA, MVC force of the leg extensor muscles for the operated leg did not differ significantly as compared to the preoperative level, whereas it remained significantly lower for the non-operated leg and controls. The knee flexion moment and the knee joint power during mid stance of gait was improved six months after TKA, remaining significantly lowered compared with controls. Negative moderate correlation between leg extensor muscles strength and knee joint loading for the operated leg during mid stance was noted three months after TKA. The correlation analysis indicates that due to weak leg extensor muscles, an excessive load is applied to knee joint during mid stance of gait in patients, whereas in healthy subjects stronger knee-surrounding muscles provide stronger knee joint loading during gait. III (correlational study). Copyright © 2013 Elsevier B.V. All rights reserved.

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.

Ultrasound elastography: the new frontier in direct measurement of muscle stiffness.

PubMed

Brandenburg, Joline E; Eby, Sarah F; Song, Pengfei; Zhao, Heng; Brault, Jeffrey S; Chen, Shigao; An, Kai-Nan

2014-11-01

The use of brightness-mode ultrasound and Doppler ultrasound in physical medicine and rehabilitation has increased dramatically. The continuing evolution of ultrasound technology has also produced ultrasound elastography, a cutting-edge technology that can directly measure the mechanical properties of tissue, including muscle stiffness. Its real-time and direct measurements of muscle stiffness can aid the diagnosis and rehabilitation of acute musculoskeletal injuries and chronic myofascial pain. It can also help monitor outcomes of interventions affecting muscle in neuromuscular and musculoskeletal diseases, and it can better inform the functional prognosis. This technology has implications for even broader use of ultrasound in physical medicine and rehabilitation practice, but more knowledge about its uses and limitations is essential to its appropriate clinical implementation. In this review, we describe different ultrasound elastography techniques for studying muscle stiffness, including strain elastography, acoustic radiation force impulse imaging, and shear-wave elastography. We discuss the basic principles of these techniques, including the strengths and limitations of their measurement capabilities. We review the current muscle research, discuss physiatric clinical applications of these techniques, and note directions for future research. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Ultrasound Elastography: The New Frontier in Direct Measurement of Muscle Stiffness

PubMed Central

Brandenburg, Joline E.; Eby, Sarah F.; Song, Pengfei; Zhao, Heng; Brault, Jeffrey S.; Chen, Shigao; An, Kai-Nan

2014-01-01

The use of brightness-mode ultrasound and Doppler ultrasound in physical medicine and rehabilitation has increased dramatically. The continuing evolution of ultrasound technology has also produced ultrasound elastography, a cutting-edge technology that can directly measure the mechanical properties of tissue, including muscle stiffness. Its real-time and direct measurements of muscle stiffness can aid the diagnosis and rehabilitation of acute musculoskeletal injuries and chronic myofascial pain. It can also help monitor outcomes of interventions affecting muscle in neuromuscular and musculoskeletal diseases, and it can better inform the functional prognosis. This technology has implications for even broader use of ultrasound in physical medicine and rehabilitation practice, but more knowledge about its uses and limitations is essential to its appropriate clinical implementation. In this review, we describe different ultrasound elastography techniques for studying muscle stiffness, including strain elastography, acoustic radiation force impulse imaging, and shear-wave elastography. We discuss the basic principles of these techniques, including the strengths and limitations of their measurement capabilities. We review the current muscle research, discuss physiatric clinical applications of these techniques, and note directions for future research. PMID:25064780

Effect of armor and carrying load on body balance and leg muscle function.

PubMed

Park, Huiju; Branson, Donna; Kim, Seonyoung; Warren, Aric; Jacobson, Bert; Petrova, Adriana; Peksoz, Semra; Kamenidis, Panagiotis

2014-01-01

This study investigated the impact of weight and weight distribution of body armor and load carriage on static body balance and leg muscle function. A series of human performance tests were conducted with seven male, healthy, right-handed military students in seven garment conditions with varying weight and weight distributions. Static body balance was assessed by analyzing the trajectory of center of plantar pressure and symmetry of weight bearing in the feet. Leg muscle functions were assessed by analyzing the peak electromyography amplitude of four selected leg muscles during walking. Results of this study showed that uneven weight distribution of garment and load beyond an additional 9 kg impaired static body balance as evidenced by increased sway of center of plantar pressure and asymmetry of weight bearing in the feet. Added weight on non-dominant side of the body created greater impediment to static balance. Increased garment weight also elevated peak EMG amplitude in the rectus femoris to maintain body balance and in the medial gastrocnemius to increase propulsive force. Negative impacts on balance and leg muscle function with increased carrying loads, particularly with an uneven weight distribution, should be stressed to soldiers, designers, and sports enthusiasts. Copyright © 2013 Elsevier B.V. All rights reserved.

Ultrasound assessment of hamstring muscle size using posterior thigh muscle thickness.

PubMed

Abe, Takashi; Loenneke, Jeremy P; Thiebaud, Robert S

2016-05-01

Several studies have investigated the relationship between ultrasound-measured muscle thickness (MT) and individual muscle cross-sectional area (CSA) and muscle volume (MV) in extremity and trunk muscles; however, the hamstring muscle has not been studied. The purpose of this study was to examine the relationship between posterior thigh MT by ultrasound and the muscle CSA and MV of the hamstring obtained by magnetic resonance imaging (MRI). Ten young women aged 20-31 had MT measured by ultrasound at three sites on the medial anterior (50% of thigh length; TL) and posterior (50% and 70% of TL) aspects of the thigh. On the same day, a series of continuous muscle CSA along the thigh was measured by MRI. In each slice, the anatomical CSA of the hamstring (biceps femoris, semitendinosus and semimembranosus) and quadriceps muscle was analysed, and the CSAs at 50% and 70% of TL and maximal CSA of the hamstring (CSAmax ) were determined. MV was calculated by multiplying CSA by slice thickness. A significant correlation was observed between posterior 50% MT and 50% hamstring CSA (r = 0·848, P = 0·002) and between posterior 70% MT and 70% hamstring CSA (r = 0·679, P = 0·031). Posterior 50% MT (r = 0·732, P = 0·016) and 50% MTxTL (r = 0·873, P = 0·001) were also correlated to hamstring MV. Anterior:posterior 50% thigh MT ratio was correlated to MV ratio of quadriceps and hamstring muscles (r = 0·803, P = 0·005). Our results suggest that posterior thigh MT reflects hamstring muscle CSA and MV. The anterior:posterior MT ratio may serve as a surrogate for MV ratio of quadriceps and hamstring. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Distribution of mercury in leg muscle and liver of game birds from Serbia

NASA Astrophysics Data System (ADS)

Janković, S.; Nikolić, D.; Stefanović, S.; Radičević, T.; Đinović-Stojanović, J.; Spirić, D.; Tanković, S.

2017-09-01

The purpose of this study was to determine the distribution of Hg levels in leg muscle and liver of game birds collected within the Serbian National residue monitoring program from 2013 to 2016. Hg levels in samples (n=464) of: pheasants (n=182), mallard (n=25), Eurasian jay (n=7), partridges (n=5) and woodcocks (n=8) were determined by ICPMS. The highest mean Hg levels were observed in leg muscle samples of woodcocks (0.071 mg/kg) and mallard (0.059 mg/kg). The lowest mean Hg level in liver was determined in partridges (0.008 mg/kg) while the highest was in pheasants (0.262 mg/kg) and mallard (0.161 mg/kg). Statistical analysis showed significantly differences between Hg levels in liver of woodcocks and mallard, as well as between them and livers of other analysed game birds. During the four years (2013-2016), 87.5% of leg muscle and 50% of woodcock livers had Hg levels that exceeded the MRL, while in mallard muscle and liver those percentages were 36% and 40%, respectively.

Active and Inactive Leg Hemodynamics during Sequential Single-Leg Interval Cycling.

PubMed

Gordon, Nicole; Abbiss, Chris R; Ihsan, Mohammed; Maiorana, Andrew J; Peiffer, Jeremiah J

2018-06-01

Leg order during sequential single-leg cycling (i.e., exercising both legs independently within a single session) may affect local muscular responses potentially influencing adaptations. This study examined the cardiovascular and skeletal muscle hemodynamic responses during double-leg and sequential single-leg cycling. Ten young healthy adults (28 ± 6 yr) completed six 1-min double-leg intervals interspersed with 1 min of passive recovery and, on a separate occasion, 12 (six with one leg followed by six with the other leg) 1-min single-leg intervals interspersed with 1 min of passive recovery. Oxygen consumption, heart rate, blood pressure, muscle oxygenation, muscle blood volume, and power output were measured throughout each session. Oxygen consumption, heart rate, and power output were not different between sets of single-leg intervals, but the average of both sets was lower than the double-leg intervals. Mean arterial pressure was higher during double-leg compared with sequential single-leg intervals (115 ± 9 vs 104 ± 9 mm Hg, P < 0.05) and higher during the initial compared with second set of single-leg intervals (108 ± 10 vs 101 ± 10 mm Hg, P < 0.05). The increase in muscle blood volume from baseline was similar between the active single leg and the double leg (267 ± 150 vs 214 ± 169 μM·cm, P = 0.26). The pattern of change in muscle blood volume from the initial to second set of intervals was significantly different (P < 0.05) when the leg was active in the initial (-52.3% ± 111.6%) compared with second set (65.1% ± 152.9%). These data indicate that the order in which each leg performs sequential single-leg cycling influences the local hemodynamic responses, with the inactive muscle influencing the stimulus experienced by the contralateral leg.

Leg blood flow is impaired during small muscle mass exercise in patients with COPD.

PubMed

Iepsen, U W; Munch, G W; Rugbjerg, M; Ryrsø, C K; Secher, N H; Hellsten, Y; Lange, P; Pedersen, B K; Thaning, P; Mortensen, S P

2017-09-01

Skeletal muscle blood flow is regulated to match the oxygen demand and dysregulation could contribute to exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). We measured leg hemodynamics and metabolites from vasoactive compounds in muscle interstitial fluid and plasma at rest, during one-legged knee-extensor exercise, and during arterial infusions of sodium nitroprusside (SNP) and acetylcholine (ACh), respectively. Ten patients with moderate to severe COPD and eight age- and sex-matched healthy controls were studied. During knee-extensor exercise (10 W), leg blood flow was lower in the patients compared with the controls (1.82 ± 0.11 vs. 2.36 ± 0.14 l/min, respectively; P < 0.05), which compromised leg oxygen delivery (372 ± 26 vs. 453 ± 32 ml O 2 /min, respectively; P < 0.05). At rest, plasma endothelin-1 (vasoconstrictor) was higher in the patients with COPD ( P < 0.05) and also tended to be higher during exercise ( P = 0.07), whereas the formation of interstitial prostacyclin (vasodilator) was only increased in the controls. There was no difference between groups in the nitrite/nitrate levels (vasodilator) in plasma or interstitial fluid during exercise. Moreover, patients and controls showed similar vasodilatory capacity in response to both endothelium-independent (SNP) and endothelium-dependent (ACh) stimulation. The results suggest that leg muscle blood flow is impaired during small muscle mass exercise in patients with COPD possibly due to impaired formation of prostacyclin and increased levels of endothelin-1. NEW & NOTEWORTHY This study demonstrates that chronic obstructive pulmonary disease (COPD) is associated with a reduced blood flow to skeletal muscle during small muscle mass exercise. In contrast to healthy individuals, interstitial prostacyclin levels did not increase during exercise and plasma endothelin-1 levels were higher in the patients with COPD. Copyright © 2017 the American Physiological

Perfusion dynamics assessment with Power Doppler ultrasound in skeletal muscle during maximal and submaximal cycling exercise.

PubMed

Heres, H M; Schoots, T; Tchang, B C Y; Rutten, M C M; Kemps, H M C; van de Vosse, F N; Lopata, R G P

2018-06-01

Assessment of limitations in the perfusion dynamics of skeletal muscle may provide insight in the pathophysiology of exercise intolerance in, e.g., heart failure patients. Power doppler ultrasound (PDUS) has been recognized as a sensitive tool for the detection of muscle blood flow. In this volunteer study (N = 30), a method is demonstrated for perfusion measurements in the vastus lateralis muscle, with PDUS, during standardized cycling exercise protocols, and the test-retest reliability has been investigated. Fixation of the ultrasound probe on the upper leg allowed for continuous PDUS measurements. Cycling exercise protocols included a submaximal and an incremental exercise to maximal power. The relative perfused area (RPA) was determined as a measure of perfusion. Absolute and relative reliability of RPA amplitude and kinetic parameters during exercise (onset, slope, maximum value) and recovery (overshoot, decay time constants) were investigated. A RPA increase during exercise followed by a signal recovery was measured in all volunteers. Amplitudes and kinetic parameters during exercise and recovery showed poor to good relative reliability (ICC ranging from 0.2-0.8), and poor to moderate absolute reliability (coefficient of variation (CV) range 18-60%). A method has been demonstrated which allows for continuous (Power Doppler) ultrasonography and assessment of perfusion dynamics in skeletal muscle during exercise. The reliability of the RPA amplitudes and kinetics ranges from poor to good, while the reliability of the RPA increase in submaximal cycling (ICC = 0.8, CV = 18%) is promising for non-invasive clinical assessment of the muscle perfusion response to daily exercise.

Passive stiffness of monoarticular lower leg muscles is influenced by knee joint angle.

PubMed

Ateş, Filiz; Andrade, Ricardo J; Freitas, Sandro R; Hug, François; Lacourpaille, Lilian; Gross, Raphael; Yucesoy, Can A; Nordez, Antoine

2018-03-01

While several studies demonstrated the occurrence of intermuscular mechanical interactions, the physiological significance of these interactions remains a matter of debate. The purpose of this study was to quantify the localized changes in the shear modulus of the gastrocnemius lateralis (GL), monoarticular dorsi- and plantar-flexor muscles induced by a change in knee angle. Participants underwent slow passive ankle rotations at the following two knee positions: knee flexed at 90° and knee fully extended. Ultrasound shear wave elastography was used to assess the muscle shear modulus of the GL, soleus [both proximally (SOL-proximal) and distally (SOL distal)], peroneus longus (PERL), and tibialis anterior (TA). This was performed during two experimental sessions (experiment I: n = 11; experiment II: n = 10). The shear modulus of each muscle was compared between the two knee positions. The shear modulus was significantly higher when the knee was fully extended than when the knee was flexed (P < 0.001) for the GL (averaged increase on the whole range of motion: + 5.8 ± 1.3 kPa), SOL distal (+ 4.5 ± 1.5 kPa), PERL (+ 1.1 ± 0.7 kPa), and TA (+ 1.6 ± 1.0 kPa). In contrast, a lower SOL-proximal shear modulus (P < 0.001, - 5.9 ± 1.0 kPa) was observed. As the muscle shear modulus is linearly related to passive muscle force, these results provide evidence of a non-negligible intermuscular mechanical interaction between the human lower leg muscles during passive ankle rotations. The role of these interactions in the production of coordinated movements requires further investigation.

Distribution of cadmium in leg muscle and liver of game birds from Serbia

NASA Astrophysics Data System (ADS)

Nikolić, D.; Đinović-Stojanović, J.; Stefanović, S.; Radičević, T.; Trbović, D.; Spirić, D.; Janković, S.

2017-09-01

The aim of this study was to present the distribution of cadmium (Cd) levels in leg muscle and liver of game birds. Samples (n=464) of: pheasants (n=182), mallards (n=25), Eurasian jay (n=7), partridges (n=5), woodcocks (n=8) and common quail (n=5) were collected during regular hunting seasons within the Serbian National Residue Monitoring Program from 2013 to 2016. Analysis of Cd was performed by ICP-MS. In all liver samples, Cd levels were above the limit of detection (LOD=0.001 mg/kg) while in 66.4% of muscle samples, Cd was detected. Statistical analysis showed significant differences between Cd levels in leg muscle and liver of woodcocks and others game birds. The highest mean Cd level was observed in muscle samples of woodcocks (0.042 mg/kg). The lowest mean Cd levels in liver were observed in common quails (0.130 mg/kg) and mallards (0.160 mg/kg) while the highest levels were measured in woodcocks (1.247 mg/kg) and pheasants (0.262 mg/kg). During four years of the Serbian National Residue Monitoring Program, leg muscle samples of woodcocks (n=3), liver samples of pheasants (n=23), woodcocks (n=6) and mallards (n=3) exceeded the maximum residue limit (MRL).

Influence of unstable footwear on lower leg muscle activity, volume change and subjective discomfort during prolonged standing.

PubMed

Karimi, Zanyar; Allahyari, Teimour; Azghani, Mahmood Reza; Khalkhali, Hamidreza

2016-03-01

The present study was an attempt to investigate the effect of unstable footwear on lower leg muscle activity, volume change and subjective discomfort during prolonged standing. Ten healthy subjects were recruited to stand for 2 h in three footwear conditions: barefoot, flat-bottomed shoe and unstable shoe. During standing, lower leg discomfort and EMG activity of medial gastrocnemius (MG) and tibialis anterior (TA) muscles were continuously monitored. Changes in lower leg volume over standing time also were measured. Lower leg discomfort rating reduced significantly while subjects standing on unstable shoe compared to the flat-bottomed shoe and barefoot condition. For lower leg volume, less changes also were observed with unstable shoe. The activity level and variation of right MG muscle was greater with unstable shoe compared to the other footwear conditions; however regarding the left MG muscle, significant difference was found between unstable shoe and flat-bottomed shoe only for activity level. Furthermore no significant differences were observed for the activity level and variation of TA muscles (right/left) among all footwear conditions. The findings suggested that prolonged standing with unstable footwear produces changes in lower leg muscles activity and leads to less volume changes. Perceived discomfort also was lower for this type of footwear and this might mean that unstable footwear can be used as ergonomic solution for employees whose work requires prolonged standing. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Protection against high intravascular pressure in giraffe legs.

PubMed

Petersen, Karin K; Hørlyck, Arne; Ostergaard, Kristine H; Andresen, Joergen; Broegger, Torbjoern; Skovgaard, Nini; Telinius, Niklas; Laher, Ismael; Bertelsen, Mads F; Grøndahl, Carsten; Smerup, Morten; Secher, Niels H; Brøndum, Emil; Hasenkam, John M; Wang, Tobias; Baandrup, Ulrik; Aalkjaer, Christian

2013-11-01

The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated in 11 giraffes whether large and small arteries in the legs and the tight fascia protect leg capillaries. Ultrasound imaging of foreleg arteries in anesthetized giraffes and ex vivo examination revealed abrupt thickening of the arterial wall and a reduction of its internal diameter just below the elbow. At and distal to this narrowing, the artery constricted spontaneously and in response to norepinephrine and intravascular pressure recordings revealed a dynamic, viscous pressure drop along the artery. Histology of the isolated median artery confirmed dense sympathetic innervation at the narrowing. Structure and contractility of small arteries from muscular beds in the leg and neck were compared. The arteries from the legs demonstrated an increased media thickness-to-lumen diameter ratio, increased media volume, and increased numbers of smooth muscle cells per segment length and furthermore, they contracted more strongly than arteries from the neck (500 ± 49 vs. 318 ± 43 mmHg; n = 6 legs and neck, respectively). Finally, the transient increase in interstitial fluid pressure following injection of saline was 5.5 ± 1.7 times larger (n = 8) in the leg than in the neck. We conclude that 1) tissue compliance in the legs is low; 2) large arteries of the legs function as resistance arteries; and 3) structural adaptation of small muscle arteries allows them to develop an extraordinary tension. All three findings can contribute to protection of the capillaries in giraffe legs from a high arterial pressure.

Diagnostic ultrasound estimates of muscle mass and muscle quality discriminate between women with and without sarcopenia

PubMed Central

Ismail, Catheeja; Zabal, Johannah; Hernandez, Haniel J.; Woletz, Paula; Manning, Heather; Teixeira, Carla; DiPietro, Loretta; Blackman, Marc R.; Harris-Love, Michael O.

2015-01-01

Introduction: Age-related changes in muscle mass and muscle tissue composition contribute to diminished strength in older adults. The objectives of this study are to examine if an assessment method using mobile diagnostic ultrasound augments well-known determinants of lean body mass (LBM) to aid sarcopenia staging, and if a sonographic measure of muscle quality is associated with muscle performance. Methods: Twenty community-dwelling female subjects participated in the study (age = 43.4 ± 20.9 years; BMI: 23.8, interquartile range: 8.5). Dual energy X-ray absorptiometry (DXA) and diagnostic ultrasound morphometry were used to estimate LBM. Muscle tissue quality was estimated via the echogenicity using grayscale histogram analysis. Peak force was measured with grip dynamometry and scaled for body size. Bivariate and multiple regression analyses were used to determine the association of the predictor variables with appendicular lean mass (aLM/ht2), and examine the relationship between scaled peak force values and muscle echogenicity. The sarcopenia LBM cut point value of 6.75 kg/m2 determined participant assignment into the Normal LBM and Low LBM subgroups. Results: The selected LBM predictor variables were body mass index (BMI), ultrasound morphometry, and age. Although BMI exhibited a significant positive relationship with aLM/ht2 (adj. R2 = 0.61, p < 0.001), the strength of association improved with the addition of ultrasound morphometry and age as predictor variables (adj. R2 = 0.85, p < 0.001). Scaled peak force was associated with age and echogenicity (adj. R2 = 0.53, p < 0.001), but not LBM. The Low LBM subgroup of women (n = 10) had higher scaled peak force, lower BMI, and lower echogenicity values in comparison to the Normal LBM subgroup (n = 10; p < 0.05). Conclusions: Diagnostic ultrasound morphometry values are associated with LBM, and improve the BMI predictive model for aLM/ht2 in women. In addition, ultrasound proxy measures of muscle quality are more

Diagnostic ultrasound estimates of muscle mass and muscle quality discriminate between women with and without sarcopenia.

PubMed

Ismail, Catheeja; Zabal, Johannah; Hernandez, Haniel J; Woletz, Paula; Manning, Heather; Teixeira, Carla; DiPietro, Loretta; Blackman, Marc R; Harris-Love, Michael O

2015-01-01

Age-related changes in muscle mass and muscle tissue composition contribute to diminished strength in older adults. The objectives of this study are to examine if an assessment method using mobile diagnostic ultrasound augments well-known determinants of lean body mass (LBM) to aid sarcopenia staging, and if a sonographic measure of muscle quality is associated with muscle performance. Twenty community-dwelling female subjects participated in the study (age = 43.4 ± 20.9 years; BMI: 23.8, interquartile range: 8.5). Dual energy X-ray absorptiometry (DXA) and diagnostic ultrasound morphometry were used to estimate LBM. Muscle tissue quality was estimated via the echogenicity using grayscale histogram analysis. Peak force was measured with grip dynamometry and scaled for body size. Bivariate and multiple regression analyses were used to determine the association of the predictor variables with appendicular lean mass (aLM/ht(2)), and examine the relationship between scaled peak force values and muscle echogenicity. The sarcopenia LBM cut point value of 6.75 kg/m(2) determined participant assignment into the Normal LBM and Low LBM subgroups. The selected LBM predictor variables were body mass index (BMI), ultrasound morphometry, and age. Although BMI exhibited a significant positive relationship with aLM/ht(2) (adj. R (2) = 0.61, p < 0.001), the strength of association improved with the addition of ultrasound morphometry and age as predictor variables (adj. R (2) = 0.85, p < 0.001). Scaled peak force was associated with age and echogenicity (adj. R (2) = 0.53, p < 0.001), but not LBM. The Low LBM subgroup of women (n = 10) had higher scaled peak force, lower BMI, and lower echogenicity values in comparison to the Normal LBM subgroup (n = 10; p < 0.05). Diagnostic ultrasound morphometry values are associated with LBM, and improve the BMI predictive model for aLM/ht(2) in women. In addition, ultrasound proxy measures of muscle quality are more strongly associated with

Abdominal muscle response to a simulated weight-bearing task by elite Australian Rules football players.

PubMed

Hyde, Jodie; Stanton, Warren R; Hides, Julie A

2012-02-01

The aim of this study was to examine the automatic recruitment of the deep abdominal muscles during a unilateral simulated weight-bearing task by elite Australian Rules football (AFL) players with and without low back pain (LBP). An observational cross-sectional study was conducted using ultrasound imaging to measure the thickness of the internal oblique (IO) and transversus abdominis (TrA) muscles. Thirty-seven elite male AFL players participated. Repeated measures factors included 'force level' (rest, 25% and 45% of body weight), 'leg' (dominant or non-dominant kicking leg) and 'side' (ultrasound side ipsilateral or contralateral to the leg used for the weight-bearing task). The dependent variables were thickness of the IO and TrA muscles. The results of this study showed that thickness of the IO (p<.0001) and TrA (p<.0001) muscles increased in response to 'force level'. During the task, the thickness of the IO muscle on the contralateral side of the trunk relative to the leg being tested, increased more in participants with current LBP (p=.034). This pattern was more distinct on the non-dominant kicking leg. Altered abdominal muscle recruitment in elite athletes with low back pain may be an attempt by the central nervous system (CNS) to compensate for inadequate lumbo-pelvic stability. Copyright © 2011 Elsevier B.V. All rights reserved.

Reliability and validity of quantifying absolute muscle hardness using ultrasound elastography.

PubMed

Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Fukashiro, Senshi; Takahashi, Hideyuki

2012-01-01

Muscle hardness is a mechanical property that represents transverse muscle stiffness. A quantitative method that uses ultrasound elastography for quantifying absolute human muscle hardness has been previously devised; however, its reliability and validity have not been completely verified. This study aimed to verify the reliability and validity of this quantitative method. The Young's moduli of seven tissue-mimicking materials (in vitro; Young's modulus range, 20-80 kPa; increments of 10 kPa) and the human medial gastrocnemius muscle (in vivo) were quantified using ultrasound elastography. On the basis of the strain/Young's modulus ratio of two reference materials, one hard and one soft (Young's moduli of 7 and 30 kPa, respectively), the Young's moduli of the tissue-mimicking materials and medial gastrocnemius muscle were calculated. The intra- and inter-investigator reliability of the method was confirmed on the basis of acceptably low coefficient of variations (≤6.9%) and substantially high intraclass correlation coefficients (≥0.77) obtained from all measurements. The correlation coefficient between the Young's moduli of the tissue-mimicking materials obtained using a mechanical method and ultrasound elastography was 0.996, which was equivalent to values previously obtained using magnetic resonance elastography. The Young's moduli of the medial gastrocnemius muscle obtained using ultrasound elastography were within the range of values previously obtained using magnetic resonance elastography. The reliability and validity of the quantitative method for measuring absolute muscle hardness using ultrasound elastography were thus verified.

The Effect of Commonly Performed Exercises on the Levator Hiatus Area and the Length and Strength of Pelvic Floor Muscles in Postpartum Women.

PubMed

Siff, Lauren N; Hill, Audra J; Walters, Samantha J; Walters, Ginny; Walters, Mark D

2018-05-02

The aim oft his study was to compare the effects of 10 common exercises to traditional pelvic floor muscle (PFM) contractions (Kegel) on levator hiatus (LH) area and PFM length and strength. This is a cross-sectional study of 15 healthy postpartum women. Ten exercises were studied. These were common variations of leg, core, and back exercises used in yoga, Pilates, strength training, and physical therapy. Each participant performed all 10 exercises at a single visit in 2 examination settings: transperineal ultrasound and perineometry. Ultrasound measured the LH area and PFM length, and perineometry measured the muscle strength (peak squeeze pressure). Kegel generates an increase in squeeze pressure (24.3 cm H2O), shortens the muscles (-0.46 cm) and narrows the LH (-0.13 cm). The bird-dog and plank exercises were not different from Kegel in any measurement. While the leg-lift ultrasound dimensions are similar to Kegel, leg lifts generated peak squeeze pressures stronger than any other exercise (including Kegel). Whereas ultrasound dimensions were similar to Kegel, tucked and untucked squats and thigh adductions generated weaker contractions than Kegel. While crunch generated a squeeze pressure similar to Kegel, the ultrasound dimensions showed a significantly wider LH and longer muscle than Kegel. Bridge, clam, and plié exercises affected the PFMs differently than Kegel in all measures. Bird-dog, plank, and leg-lift exercises should be evaluated as alternative exercises to Kegel as they affect PFM strength and length and LH area similarly to Kegel, and leg lifts generate a stronger contraction than Kegel.

Onset in abdominal muscles recorded simultaneously by ultrasound imaging and intramuscular electromyography.

PubMed

Vasseljen, Ottar; Fladmark, Anne M; Westad, Christian; Torp, Hans G

2009-04-01

Delayed onset of muscle activity in abdominal muscles has been related to low back pain. To investigate this in larger clinical trials it would be beneficial if non-invasive and less cumbersome alternatives to intramuscular electromyography (EMG) were available. This study was designed to compare onset of muscle activity recorded by intramuscular EMG to onset of muscle deformations by ultrasound imaging. Muscle deformations were recorded by two ultrasound imaging modes at high time resolution (m-mode and tissue velocity) in separate sessions and compared to simultaneously recorded intramuscular EMG in three abdominal muscles. Tissue velocity imaging was converted to strain rate which measures deformation velocity gradients within small regions, giving information about the rate of local tissue shortening or lengthening along the beam axis. Onsets in transversus abdominis (TrA), obliquus internus abdominis (OI) and obliquus externus abdominis (OE) were recorded during rapid arm flexions in ten healthy subjects. During ultrasound m-mode recordings, the results showed that mean onsets by EMG were detected 7 ms (95% CI of mean difference; +/-4 ms) and 2 ms (95% CI of mean difference; +/-6 ms) before concurrent ultrasound m-mode detected onsets in TrA and OI, respectively. In contrast, OE onset was recorded 54 ms (95% CI of bias; +/-16 ms) later by EMG compared to ultrasound m-mode. The discrepancy of ultrasound m-mode to accurately record onset in OE was practically corrected in the ultrasound-based strain rate recordings. However, this could only be applied on half of the subjects due to the angle dependency between the ultrasound beam and the direction of the contraction in strain rate recordings. The angle dependency needs to be further explored.

Blood ammonia and lactate as markers of muscle metabolites during leg press exercise.

PubMed

Gorostiaga, Esteban M; Navarro-Amézqueta, Ion; Calbet, Jose A L; Sánchez-Medina, Luis; Cusso, Roser; Guerrero, Mario; Granados, Cristina; González-Izal, Miriam; Ibáñez, Javier; Izquierdo, Mikel

2014-10-01

To examine whether blood lactate and ammonia concentrations can be used to estimate the functional state of the muscle contractile machinery with regard to muscle lactate and adenosine triphosphate (ATP) levels during leg press exercise. Thirteen men (age, 34 ± 5 years; 1 repetition maximum leg press strength 199 ± 33 kg) performed either 5 sets of 10 repetitions to failure (5×10RF), or 10 sets of 5 repetitions not to failure (10×5RNF) with the same initial load (10RM) and interset rests (2 minutes) on 2 separate sessions in random order. Capillary blood samples were obtained before and during exercise and recovery. Six subjects underwent vastus lateralis muscle biopsies at rest, before the first set and after the final exercise set. The 5×10RF resulted in a significant and marked decrease in power output (37%), muscle ATP content (24%), and high levels of muscle lactate (25.0 ± 8.1 mmol·kg wet weight), blood lactate (10.3 ± 2.6 mmol·L), and blood ammonia (91.6 ± 40.5 μmol·L). During 10×5RNF no or minimal changes were observed. Significant correlations were found between: (a) blood ammonia and muscle ATP (r = -0.75), (b) changes in peak power output and blood ammonia (r = -0.87) and blood lactate (r = -0.84), and (c) blood and muscle lactate (r = 0.90). Blood lactate and ammonia concentrations can be used as extracellular markers for muscle lactate and ATP contents, respectively. The decline in mechanical power output can be used to indirectly estimate blood ammonia and lactate during leg press exercise.

Reliability and Validity of Quantifying Absolute Muscle Hardness Using Ultrasound Elastography

PubMed Central

Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Fukashiro, Senshi; Takahashi, Hideyuki

2012-01-01

Muscle hardness is a mechanical property that represents transverse muscle stiffness. A quantitative method that uses ultrasound elastography for quantifying absolute human muscle hardness has been previously devised; however, its reliability and validity have not been completely verified. This study aimed to verify the reliability and validity of this quantitative method. The Young’s moduli of seven tissue-mimicking materials (in vitro; Young’s modulus range, 20–80 kPa; increments of 10 kPa) and the human medial gastrocnemius muscle (in vivo) were quantified using ultrasound elastography. On the basis of the strain/Young’s modulus ratio of two reference materials, one hard and one soft (Young’s moduli of 7 and 30 kPa, respectively), the Young’s moduli of the tissue-mimicking materials and medial gastrocnemius muscle were calculated. The intra- and inter-investigator reliability of the method was confirmed on the basis of acceptably low coefficient of variations (≤6.9%) and substantially high intraclass correlation coefficients (≥0.77) obtained from all measurements. The correlation coefficient between the Young’s moduli of the tissue-mimicking materials obtained using a mechanical method and ultrasound elastography was 0.996, which was equivalent to values previously obtained using magnetic resonance elastography. The Young’s moduli of the medial gastrocnemius muscle obtained using ultrasound elastography were within the range of values previously obtained using magnetic resonance elastography. The reliability and validity of the quantitative method for measuring absolute muscle hardness using ultrasound elastography were thus verified. PMID:23029231

Validation of musculoskeletal ultrasound to assess and quantify muscle glycogen content. A novel approach.

PubMed

Hill, John C; Millán, Iñigo San

2014-09-01

Glycogen storage is essential for exercise performance. The ability to assess muscle glycogen levels should be an important advantage for performance. However, skeletal muscle glycogen assessment has only been available and validated through muscle biopsy. We have developed a new methodology using high-frequency ultrasound to assess skeletal muscle glycogen content in a rapid, portable, and noninvasive way using MuscleSound (MuscleSound, LCC, Denver, CO) technology. To validate the utilization of high-frequency musculoskeletal ultrasound for muscle glycogen assessment and correlate it with histochemical glycogen quantification through muscle biopsy. Twenty-two male competitive cyclists (categories: Pro, 1-4; average height, 183.7 ± 4.9 cm; average weight, 76.8 ± 7.8 kg) performed a steady-state test on a cyclergometer for 90 minutes at a moderate to high exercise intensity, eliciting a carbohydrate oxidation of 2-3 g·min⁻¹ and a blood lactate concentration of 2 to 3 mM. Pre- and post-exercise glycogen content from rectus femoris muscle was measured using histochemical analysis through muscle biopsy and through high-frequency ultrasound scans using MuscleSound technology. Correlations between muscle biopsy glycogen histochemical quantification (mmol·kg⁻¹) and high-frequency ultrasound methodology through MuscleSound technology were r = 0.93 (P < 0.0001) pre-exercise and r = 0.94 (P < 0.0001) post-exercise. The correlation between muscle biopsy glycogen quantification and high-frequency ultrasound methodology for the change in glycogen from pre- and post-exercise was r = 0.81 (P < 0.0001). These results demonstrate that skeletal muscle glycogen can be measured quickly and noninvasively through high-frequency ultrasound using MuscleSound technology.

Maintained peak leg and pulmonary VO2 despite substantial reduction in muscle mitochondrial capacity.

PubMed

Boushel, R; Gnaiger, E; Larsen, F J; Helge, J W; González-Alonso, J; Ara, I; Munch-Andersen, T; van Hall, G; Søndergaard, H; Saltin, B; Calbet, J A L

2015-12-01

We recently reported the circulatory and muscle oxidative capacities of the arm after prolonged low-intensity skiing in the arctic (Boushel et al., 2014). In the present study, leg VO2 was measured by the Fick method during leg cycling while muscle mitochondrial capacity was examined on a biopsy of the vastus lateralis in healthy volunteers (7 male, 2 female) before and after 42 days of skiing at 60% HR max. Peak pulmonary VO2 (3.52 ± 0.18 L.min(-1) pre vs 3.52 ± 0.19 post) and VO2 across the leg (2.8 ± 0.4L.min(-1) pre vs 3.0 ± 0.2 post) were unchanged after the ski journey. Peak leg O2 delivery (3.6 ± 0.2 L.min(-1) pre vs 3.8 ± 0.4 post), O2 extraction (82 ± 1% pre vs 83 ± 1 post), and muscle capillaries per mm(2) (576 ± 17 pre vs 612 ± 28 post) were also unchanged; however, leg muscle mitochondrial OXPHOS capacity was reduced (90 ± 3 pmol.sec(-1) .mg(-1) pre vs 70 ± 2 post, P < 0.05) as was citrate synthase activity (40 ± 3 μmol.min(-1) .g(-1) pre vs 34 ± 3 vs P < 0.05). These findings indicate that peak muscle VO2 can be sustained with a substantial reduction in mitochondrial OXPHOS capacity. This is achieved at a similar O2 delivery and a higher relative ADP-stimulated mitochondrial respiration at a higher mitochondrial p50. These findings support the concept that muscle mitochondrial respiration is submaximal at VO2max , and that mitochondrial volume can be downregulated by chronic energy demand. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Motor-Neuron Pool Excitability of the Lower Leg Muscles After Acute Lateral Ankle Sprain

PubMed Central

Klykken, Lindsey W.; Pietrosimone, Brian G.; Kim, Kyung-Min; Ingersoll, Christopher D.; Hertel, Jay

2011-01-01

Context: Neuromuscular deficits in leg muscles that are associated with arthrogenic muscle inhibition have been reported in people with chronic ankle instability, yet whether these neuromuscular alterations are present in individuals with acute sprains is unknown. Objective: To compare the effect of acute lateral ankle sprain on the motor-neuron pool excitability (MNPE) of injured leg muscles with that of uninjured contralateral leg muscles and the leg muscles of healthy controls. Design: Case-control study. Setting: Laboratory. Patients or Other Participants: Ten individuals with acute ankle sprains (6 females, 4 males; age = 19.2 ± 3.8 years, height = 169.4 ± 8.5 cm, mass = 66.3 ±11.6 kg) and 10 healthy individuals (6 females, 4 males; age = 20.6 ± 4.0 years, height = 169.9 ± 10.6 cm, mass = 66.3 ± 10.2 kg) participated. Intervention(s): The independent variables were group (acute ankle sprain, healthy) and limb (injured, uninjured). Separate dependent t tests were used to determine differences in MNPE between legs. Main Outcome Measure(s): The MNPE of the soleus, fibularis longus, and tibialis anterior was measured by the maximal Hoffmann reflex (Hmax) and maximal muscle response (Mmax) and was then normalized using the Hmax:Mmax ratio. Results: The soleus MNPE in the ankle-sprain group was higher in the injured limb (Hmax:Mmax = 0.63; 95% confidence interval [CI], 0.46, 0.80) than in the uninjured limb (Hmax:Mmax = 0.47; 95% CI, 0.08, 0.93) (t6 = 3.62, P = .01). In the acute ankle-sprain group, tibialis anterior MNPE tended to be lower in the injured ankle (Hmax:Mmax = 0.06; 95% CI, 0.01, 0.10) than in the uninjured ankle (Hmax:Mmax = 0.22; 95% CI, 0.09, 0.35), but this finding was not different (t9 = −2.01, P = .07). No differences were detected between injured (0.22; 95% CI, 0.14, 0.29) and uninjured (0.25; 95% CI, 0.12, 0.38) ankles for the fibularis longus in the ankle-sprain group (t9 = −0.739, P = .48). We found no side-to-side differences in

Motor-neuron pool excitability of the lower leg muscles after acute lateral ankle sprain.

PubMed

Klykken, Lindsey W; Pietrosimone, Brian G; Kim, Kyung-Min; Ingersoll, Christopher D; Hertel, Jay

2011-01-01

Neuromuscular deficits in leg muscles that are associated with arthrogenic muscle inhibition have been reported in people with chronic ankle instability, yet whether these neuromuscular alterations are present in individuals with acute sprains is unknown. To compare the effect of acute lateral ankle sprain on the motor-neuron pool excitability (MNPE) of injured leg muscles with that of uninjured contralateral leg muscles and the leg muscles of healthy controls. Case-control study. Laboratory. Ten individuals with acute ankle sprains (6 females, 4 males; age= 19.2 ± 3.8 years, height= 169.4 ± 8.5 cm, mass= 66.3 ± 11.6 kg) and 10 healthy individuals(6 females,4 males; age= 20.6 ± 4.0 years, height = 169.9 ± 10.6 cm, mass= 66.3 ± 10.2 kg) participated. The independent variables were group (acute ankle sprain, healthy) and limb (injured, uninjured). Separate dependent t tests were used to determine differences in MNPE between legs. The MNPE of the soleus, fibularis longus, and tibialis anterior was measured by the maximal Hoffmann reflex (H(max)) and maximal muscle response (M(max)) and was then normalized using the H(max):M(max) ratio. The soleus MNPE in the ankle-sprain group was higher in the injured limb (H(max):M(max) = 0.63; 95% confidence interval [Cl],0.46, 0.80) than the uninjured limb (H(max):M(max) = 0.47; 95%Cl, 0.08, 0.93)(t(6) = 3.62,P =.01).In the acute ankle-sprain group, tibialis anterior MNPE tended to be lower in the injured ankle (H(max):M(max) =0.06; 95% Cl, 0.01, 0.10) than in the uninjured ankle (H(max):M(max) =0.22; 95%Cl, 0.09, 0.35),but this finding was not different (t(9) =-2.01, P =.07). No differences were detected between injured (0.22; 95% Cl, 0.14, 0.29) and uninjured (0.25; 95%Cl, 0.12, 0.38) ankles for the fibularis longus in the ankle-sprain group (t(9) =-0.739, P =.48). We found no side-to-side differences in any muscle among the healthy group. Facilitated MNPE was present in the involved soleus muscle of patients with acute

Human Leg Model Predicts Muscle Forces, States, and Energetics during Walking.

PubMed

Markowitz, Jared; Herr, Hugh

2016-05-01

Humans employ a high degree of redundancy in joint actuation, with different combinations of muscle and tendon action providing the same net joint torque. Both the resolution of these redundancies and the energetics of such systems depend on the dynamic properties of muscles and tendons, particularly their force-length relations. Current walking models that use stock parameters when simulating muscle-tendon dynamics tend to significantly overestimate metabolic consumption, perhaps because they do not adequately consider the role of elasticity. As an alternative, we posit that the muscle-tendon morphology of the human leg has evolved to maximize the metabolic efficiency of walking at self-selected speed. We use a data-driven approach to evaluate this hypothesis, utilizing kinematic, kinetic, electromyographic (EMG), and metabolic data taken from five participants walking at self-selected speed. The kinematic and kinetic data are used to estimate muscle-tendon lengths, muscle moment arms, and joint moments while the EMG data are used to estimate muscle activations. For each subject we perform an optimization using prescribed skeletal kinematics, varying the parameters that govern the force-length curve of each tendon as well as the strength and optimal fiber length of each muscle while seeking to simultaneously minimize metabolic cost and maximize agreement with the estimated joint moments. We find that the metabolic cost of transport (MCOT) values of our participants may be correctly matched (on average 0.36±0.02 predicted, 0.35±0.02 measured) with acceptable joint torque fidelity through application of a single constraint to the muscle metabolic budget. The associated optimal muscle-tendon parameter sets allow us to estimate the forces and states of individual muscles, resolving redundancies in joint actuation and lending insight into the potential roles and control objectives of the muscles of the leg throughout the gait cycle.

The relationship of hip muscle performance to leg, ankle and foot injuries: a systematic review.

PubMed

Steinberg, Nili; Dar, Gali; Dunlop, Martin; Gaida, James Edmund

2017-02-01

Hip control affects movement and muscle firing patterns in the leg, ankle and foot, and may contribute to overuse injuries. Muscle performance can be measured as strength, endurance or muscle activation patterns. Our objective was to systematically review whether hip muscle performance is associated with leg, ankle and foot injuries. A structured and comprehensive search of six medical literature databases was combined with forward and backward citation tracking (AMED, CINAHL, EMBASE, Medline, Scopus and SportDiscus). Eligible studies measured hip muscle performance in individuals with musculoskeletal injuries below the tibial tuberosity, using dynamometry or electromyography (EMG). All studies compared an injured group with a control group or compared the injured and non-injured limb in the same individual. Data was extracted from each study independently by two authors. Twenty case-control and four prospective studies (n = 24) met the inclusion criteria. Injury classifications included chronic ankle instability (n = 18), Achilles tendinopathy (n = 2), medial tibial stress syndrome and tibial stress fracture (n = 1), posterior tibial tendon dysfunction (n = 1), and exertional medial tibial pain (n = 2). Eleven of the studies revealed differences in hip muscle performance indicating less strength, delayed onset activation and decreased duration of activation in the injured groups. Two studies found evidence for differences between groups only in some of their measurements. Three out of the four prospective studies revealed that hip muscle performance was not a risk factor for leg, ankle and foot injuries. This review provides limited evidence that hip muscle performance variables are related to leg, ankle and foot injuries. Emerging evidence indicates this might be a result of the injury rather than a contributor to the injury.

Analysis of ultrasound pulse-echo images for characterization of muscle disease

NASA Astrophysics Data System (ADS)

Leeman, Sidney; Heckmatt, John Z.

1996-04-01

This study aims to extract quantifiable indices characterizing ultrasound propagation and scattering in skeletal muscle, from data acquired using a real-time linear array scanner in a paediatric muscle clinic, in order to establish early diagnosis of Duchenne muscular dystrophy in young children, as well as to chart the progressive severity of the disease. Approximately 40 patients with gait disorders, aged between 1 and 11 years, were scanned with a real-time linear array ultrasound scanner, at 5 MHz. A control group consisted of approximately 50 boys, in the same age range, with no evidence or history of muscle disease. Results show that ultrasound quantitative methods can provide a tight clustering of normal data, and also provide a basis for charting the degree of change in diseased muscle. The most significant (quantitative) parameters derive from the frequency of the attenuation and the muscle echogenicity. The approach provides a discrimination method that is more sensitive than visual assessment of the corresponding image by even an experienced observer. There are also indications that the need for traumatic muscle biopsy may be obviated in some cases.

BUILDING A BETTER GLUTEAL BRIDGE: ELECTROMYOGRAPHIC ANALYSIS OF HIP MUSCLE ACTIVITY DURING MODIFIED SINGLE-LEG BRIDGES.

PubMed

Lehecka, B J; Edwards, Michael; Haverkamp, Ryan; Martin, Lani; Porter, Kambry; Thach, Kailey; Sack, Richard J; Hakansson, Nils A

2017-08-01

Gluteal strength plays a role in injury prevention, normal gait patterns, eliminating pain, and enhancing athletic performance. Research shows high gluteal muscle activity during a single-leg bridge compared to other gluteal strengthening exercises; however, prior studies have primarily measured muscle activity with the active lower extremity starting in 90 ° of knee flexion with an extended contralateral knee. This standard position has caused reports of hamstring cramping, which may impede optimal gluteal strengthening. The purpose of this study was to determine which modified position for the single-leg bridge is best for preferentially activating the gluteus maximus and medius. Cross-Sectional. Twenty-eight healthy males and females aged 18-30 years were tested in five different, randomized single-leg bridge positions. Electromyography (EMG) electrodes were placed on subjects' gluteus maximus, gluteus medius, rectus femoris, and biceps femoris of their bridge leg (i.e., dominant or kicking leg), as well as the rectus femoris of their contralateral leg. Subjects performed a maximal voluntary isometric contraction (MVIC) for each tested muscle prior to performing five different bridge positions in randomized order. All bridge EMG data were normalized to the corresponding muscle MVIC data. A modified bridge position with the knee of the bridge leg flexed to 135 ° versus the traditional 90 ° of knee flexion demonstrated preferential activation of the gluteus maximus and gluteus medius compared to the traditional single-leg bridge. Hamstring activation significantly decreased (p < 0.05) when the dominant knee was flexed to 135 ° (23.49% MVIC) versus the traditional 90 ° (75.34% MVIC), while gluteal activation remained similarly high (51.01% and 57.81% MVIC in the traditional position, versus 47.35% and 57.23% MVIC in the modified position for the gluteus maximus and medius, respectively). Modifying the traditional single-leg bridge by flexing the

Age-related differences in skeletal muscle microvascular response to exercise as detected by contrast-enhanced ultrasound (CEUS).

PubMed

Hildebrandt, Wulf; Schwarzbach, Hans; Pardun, Anita; Hannemann, Lena; Bogs, Björn; König, Alexander M; Mahnken, Andreas H; Hildebrandt, Olaf; Koehler, Ulrich; Kinscherf, Ralf

2017-01-01

Aging involves reductions in exercise total limb blood flow and exercise capacity. We hypothesized that this may involve early age-related impairments of skeletal muscle microvascular responsiveness as previously reported for insulin but not for exercise stimuli in humans. Using an isometric exercise model, we studied the effect of age on contrast-enhanced ultrasound (CEUS) parameters, i.e. microvascular blood volume (MBV), flow velocity (MFV) and blood flow (MBF) calculated from replenishment of Sonovue contrast-agent microbubbles after their destruction. CEUS was applied to the vastus lateralis (VLat) and intermedius (VInt) muscle in 15 middle-aged (MA, 43.6±1.5 years) and 11 young (YG, 24.1±0.6 years) healthy males before, during, and after 2 min of isometric knee extension at 15% of peak torque (PT). In addition, total leg blood flow as recorded by femoral artery Doppler-flow. Moreover, fiber-type-specific and overall capillarisation as well as fiber composition were additionally assessed in Vlat biopsies obtained from CEUS site. MA and YG had similar quadriceps muscle MRT-volume or PT and maximal oxygen uptake as well as a normal cardiovascular risk factors and intima-media-thickness. During isometric exercise MA compared to YG reached significantly lower levels in MFV (0.123±0.016 vs. 0.208±0.036 a.u.) and MBF (0.007±0.001 vs. 0.012±0.002 a.u.). In the VInt the (post-occlusive hyperemia) post-exercise peaks in MBV and MBF were significantly lower in MA vs. YG. Capillary density, capillary fiber contacts and femoral artery Doppler were similar between MA and YG. In the absence of significant age-related reductions in capillarisation, total leg blood flow or muscle mass, healthy middle-aged males reveal impaired skeletal muscle microcirculatory responses to isometric exercise. Whether this limits isometric muscle performance remains to be assessed.

Ultrasound Imaging of Muscle Contraction of the Tibialis Anterior in Patients with Facioscapulohumeral Dystrophy.

PubMed

Gijsbertse, Kaj; Goselink, Rianne; Lassche, Saskia; Nillesen, Maartje; Sprengers, André; Verdonschot, Nico; van Alfen, Nens; de Korte, Chris

2017-11-01

A need exists for biomarkers to diagnose, quantify and longitudinally follow facioscapulohumeral muscular dystrophy (FSHD) and many other neuromuscular disorders. Furthermore, the pathophysiological mechanisms leading to muscle weakness in most neuromuscular disorders are not completely understood. Dynamic ultrasound imaging (B-mode image sequences) in combination with speckle tracking is an easy, applicable and patient-friendly imaging tool to visualize and quantify muscle deformation. This dynamic information provides insight in the pathophysiological mechanisms and may help to distinguish the various stages of diseased muscle in FSHD. In this proof-of-principle study, we applied a speckle tracking technique to 2-D ultrasound image sequences to quantify the deformation of the tibialis anterior muscle in patients with FSHD and in healthy controls. The resulting deformation patterns were compared with muscle ultrasound echo intensity analysis (a measure of fat infiltration and dystrophy) and clinical outcome measures. Of the four FSHD patients, two patients had severe peroneal weakness and two patients had mild peroneal weakness on clinical examination. We found a markedly varied muscle deformation pattern between these groups: patients with severe peroneal weakness showed a different motion pattern of the tibialis anterior, with overall less displacement of the central tendon region, while healthy patients showed a non-uniform displacement pattern, with the central aponeurosis showing the largest displacement. Hence, dynamic muscle ultrasound of the tibialis anterior muscle in patients with FSHD revealed a distinctively different tissue deformation pattern among persons with and without tibialis anterior weakness. These findings could clarify the understanding of the pathophysiology of muscle weakness in FSHD patients. In addition, the change in muscle deformation shows good correlation with clinical measures and quantitative muscle ultrasound measurements. In

Hemodynamic Changes in Rat Leg Muscles during Tourniquet-induced Ischemia-reperfusion Injury Observed by Near-infrared Spectroscopy

DTIC Science & Technology

2009-07-01

leg muscle during pressure increase (Arbabi et al 1999) and in the human leg muscle during exercise (Breit et al 1997, Egun et al 2002, van den Brand...time of flight measurement. Phys Med Biol 1988;33:1433–42. [PubMed: 3237772] Egun A, Farooq V, Torella F, Cowley R, Thorniley MS, McCollum CN. The

The influence of estradiol on muscle damage and leg strength after intense eccentric exercise.

PubMed

Minahan, Clare; Joyce, Sarah; Bulmer, Andrew C; Cronin, Neil; Sabapathy, Surendran

2015-07-01

To examine the influence of estradiol on muscle damage and leg strength after intense eccentric exercise. Eight men (MEN), eight normally menstruating women (WomenNM), and eight women using oral contraceptives (WomenOC) participated in this study. Subjects performed 240 maximal-effort bilateral eccentric contractions of the quadriceps muscle groups designed to elicit exercise-induced muscle damage (EiMD). Serum creatine kinase (CK), myoglobin (Mb), and fatty acid-binding protein (FABP) concentrations were measured before (pre-) EiMD, as well as 0, 6, 24, and 48 h post-EiMD. Peak isometric quadriceps torque (i.e., leg strength) was measured pre-EiMD, as well as 24 and 48 h post-EiMD. The increases in CK, Mb, and FABP concentrations from pre- to post-EiMD were greater in MEN (10-fold, 15-fold, and fourfold, respectively) and WomenOC (sevenfold, 11-fold, and ninefold) compared with WomenNM (five-, six-, and threefold; p < 0.05). The decline in leg strength was about 10 % pre- to 24 h post-EiMD in all groups and decreased a further 10-15 % by 48 h post-EiMD in the MEN and WomenOC only. Our findings suggest an important role of estradiol in blunting the muscle damage response to intense eccentric exercise and preserving muscle function after EiMD.

Ultrasound elastography-based assessment of the elasticity of the supraspinatus muscle and tendon during muscle contraction.

PubMed

Muraki, Takayuki; Ishikawa, Hiroaki; Morise, Shuhei; Yamamoto, Nobuyuki; Sano, Hirotaka; Itoi, Eiji; Izumi, Shin-ichi

2015-01-01

Although elasticity of the supraspinatus muscle and tendon is a useful parameter to represent the conditions of the supraspinatus muscle and tendon, assessment of the elasticity in clinical settings has not been established. The purpose of this study was to determine the elasticity of the supraspinatus muscle belly and tendon under different muscle contraction conditions using ultrasound real-time tissue elastography (RTE). Twenty-three healthy individuals participated in this study. Ultrasound RTE was used for elasticity measurements of the muscle belly and tendon of the supraspinatus muscle. The elasticity was defined as the ratio of strain in the tissues to that in an acoustic coupler (reference). A greater ratio indicated that the tissue was softer. Measurements were performed with study subjects in the lateral decubitus position at 10° of shoulder abduction under conditions of (1) no contraction, (2) isometric contraction without a weight, and (3) isometric contraction with a 1-kg weight. The intraclass correlation coefficient (ICC1,3) of 3 measurements under each condition ranged from 0.931 to 0.998, showing high intraobserver reliability. Strain ratios for both the supraspinatus muscle belly and tendon significantly decreased with increases in muscle contraction (P < .001). Ultrasound RTE with the acoustic coupler has the potential to noninvasively detect changes in the elasticity of the supraspinatus muscle belly and tendon that accompany varying levels of muscle contraction in clinical practice. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

[Ultrasound diagnostics of muscle and tendon injuries].

PubMed

Stević, Ruza; Masulović, Dragan

2009-01-01

Sonography is a useful technique for the investigation of a number of musculoskeletal disorders. The most common indication for ultrasonography of muscles and tendons is the diagnosis of traumatic lesions, distinguishing them from other disorders and follow- up of healing process. The purpose of this paper is to show the importance of ultrasound in the diagnosis of muscle and tendon injuries. The study included 170 patients (148 male and 22 female), mean age 29.6 years (range 14-60 years). All examinations were performed by linear transducer of 7.5-10 MHz, with longitudinal and transverse scanning. Ultrasound examination followed physical examination. Traumatic lesions of muscles were diagnosed in 113 patients (66.7%) and tendon injuries in 57 cases (33.2%). The muscle changes detected by ultrasonography were the following: 70 (61.9%) partial and two (1.76%) complete ruptures, 22 (19.46%) haematoma, 9 (7.96%) strains grade I, 4 fibroses and 4 ossifying myositis 4 (3.5%, respectively). Complications of muscle injuries were diagnosed in two cases, a muscular hernia and an arteriovenous fistula. Among tendon injuries, 21 (33.8%) ruptures and 36 (66.1%) tendinitis were diagnosed. Accompanying effusion in the bursa of patients with tendon injuries was found in 9 cases. Ultrasonography allowed visualization and objective assessment of the type and the extent of traumatic pathomorphological changes of muscles and tendons. Such diagnostic possibilities of ultrasonography are especially important in the choice of appropriate therapy.

A common neural element receiving rhythmic arm and leg activity as assessed by reflex modulation in arm muscles

PubMed Central

Tazoe, Toshiki; Nakajima, Tsuyoshi; Futatsubashi, Genki; Ohtsuka, Hiroyuki; Suzuki, Shinya; Zehr, E. Paul; Komiyama, Tomoyoshi

2016-01-01

Neural interactions between regulatory systems for rhythmic arm and leg movements are an intriguing issue in locomotor neuroscience. Amplitudes of early latency cutaneous reflexes (ELCRs) in stationary arm muscles are modulated during rhythmic leg or arm cycling but not during limb positioning or voluntary contraction. This suggests that interneurons mediating ELCRs to arm muscles integrate outputs from neural systems controlling rhythmic limb movements. Alternatively, outputs could be integrated at the motoneuron and/or supraspinal levels. We examined whether a separate effect on the ELCR pathways and cortico-motoneuronal excitability during arm and leg cycling is integrated by neural elements common to the lumbo-sacral and cervical spinal cord. The subjects performed bilateral leg cycling (LEG), contralateral arm cycling (ARM), and simultaneous contralateral arm and bilateral leg cycling (A&L), while ELCRs in the wrist flexor and shoulder flexor muscles were evoked by superficial radial (SR) nerve stimulation. ELCR amplitudes were facilitated by cycling tasks and were larger during A&L than during ARM and LEG. A low stimulus intensity during ARM or LEG generated a larger ELCR during A&L than the sum of ELCRs during ARM and LEG. We confirmed this nonlinear increase in single motor unit firing probability following SR nerve stimulation during A&L. Furthermore, motor-evoked potentials following transcranial magnetic and electrical stimulation did not show nonlinear potentiation during A&L. These findings suggest the existence of a common neural element of the ELCR reflex pathway that is active only during rhythmic arm and leg movement and receives convergent input from contralateral arms and legs. PMID:26961103

Near-Infrared Spectroscopic Measurement of the Effect of Leg Dominance on Muscle Oxygen Saturation During Cycling

NASA Technical Reports Server (NTRS)

Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Paunescu, Lelia Adelina; Pereira, Chelsea; Smith, Charles P.; Soller, Babs R.

2011-01-01

The effect of leg dominance on the symmetry of the biomechanics during cycling remains uncertain -- asymmetries have been observed in kinematics and kinetics, while symmetries were found in muscle activation. No studies have yet investigated the symmetry of muscle metabolism during cycling. Near-infrared spectroscopy (NIRS) provides a non-invasive method to investigate the metabolic responses of specific muscles during cycling. PURPOSE: To determine whether there was an effect of leg dominance on thigh muscle oxygen saturation (SmO2) during incrementally loaded submaximal cycling using NIRS. METHODS: Eight right leg dominant, untrained subjects (5 men, 3 women; 31+/-2 yrs; 168.6+/-1.0 cm; 67.2+/-1.8 kg, mean +/- SE) volunteered to participate. Spectra were collected bilaterally from the vastus lateralis (VL) during supine rest and cycling. SmO2 was calculated using previously published methods. Subjects pedaled at 65 rpm while resistance to pedaling was increased in 0.5 kp increments from 0.5 kp every 3 min until the subject reached 80% of age-predicted maximal heart rate. SmO2 was averaged over 3 min for each completed stage. A two-way ANOVA was performed to test for leg differences. A priori contrasts were used to compare work levels to rest. RESULTS: VL SmO2 was not different between the dominant and non-dominant legs at rest and during exercise (p=0.57). How SmO2 changed with workload was also not different between legs (p=0.32). SmO2 at 0.5 kp (60.3+/-4.0, p=0.12) and 1.0 kp (59.5+/-4.0, p=0.10) was not different from rest (69.1+/-4.0). SmO2 at 1.5 kp (55.4 4.0, p=0.02), 2.0 kp (55.7+/-5.0, p=0.04), and 2.5 kp (43.4+/-7.9, p=0.01) was significantly lower than rest. CONCLUSION: VL SmO2 during cycling is not different between dominant and non-dominant legs and decreases with moderate workload in untrained cyclists. Assuming blood flow is directed equally to both legs, similar levels of oxygen extraction (as indicated by SmO2) suggests the metabolic load of

Physiological cross-sectional area of human leg muscles based on magnetic resonance imaging

NASA Technical Reports Server (NTRS)

Fukunaga, T.; Roy, R. R.; Shellock, F. G.; Hodgson, J. A.; Day, M. K.; Lee, P. L.; Kwong-Fu, H.; Edgerton, V. R.

1992-01-01

Magnetic resonance imaging techniques were used to determine the physiological cross-sectional areas (PCSAs) of the major muscles or muscle groups of the lower leg. For 12 healthy subjects, the boundaries of each muscle or muscle group were digitized from images taken at 1-cm intervals along the length of the leg. Muscle volumes were calculated from the summation of each anatomical CSA (ACSA) and the distance between each section. Muscle length was determined as the distance between the most proximal and distal images in which the muscle was visible. The PCSA of each muscle was calculated as muscle volume times the cosine of the angle of fiber pinnation divided by fiber length, where published fiber length:muscle length ratios were used to estimate fiber lengths. The mean volumes of the major plantarflexors were 489, 245, and 140 cm3 for the soleus and medial (MG) and lateral (LG) heads of the gastrocnemius. The mean PCSA of the soleus was 230 cm2, about three and eight times larger than the MG (68 cm2) and LG (28 cm2), respectively. These PCSA values were eight (soleus), four (MG), and three (LG) times larger than their respective maximum ACSA. The major dorsiflexor, the tibialis anterior (TA), had a muscle volume of 143 cm2, a PCSA of 19 cm2, and an ACSA of 9 cm2. With the exception of the soleus, the mean fiber length of all subjects was closely related to muscle volume across muscles. The soleus fibers were unusually short relative to the muscle volume, thus potentiating its force potential.(ABSTRACT TRUNCATED AT 250 WORDS).

Temperature Changes During Therapeutic Ultrasound in the Precooled Human Gastrocnemius Muscle

PubMed Central

Rimington, Stephanie J.; Draper, David O.; Durrant, Earlene; Fellingham, Gilbert

1994-01-01

Therapeutic ultrasound is frequently employed as a deep heating rehabilitation modality. It is administered in one of three ways: a) ultrasound with no preceding treatment, b) ultrasound on preheated tissues, or c) ultrasound on precooled tissues. The purpose of this study was to investigate the effect of ultrasound treatments on the tissue temperature rise of precooled human gastrocnemius muscle. Sixteen male subjects had a 23-gauge hypodermic needle microprobe inserted 3 cm deep into the medial aspect of their anesthetized gastrocnemius muscles. Data were gathered on each subject for one of two randomly assigned treatments: a) ultrasound treatment on precooled tissue, or b) ultrasound with no preceding treatment. Each treatment consisted of ultrasound delivered topically at 1.5 watts/cm2 in a continuous mode for 10 minutes. Ultrasound was applied in an overlapping longitudinal motion at 4 cm/s, with temperature readings recorded at 30-second intervals. We discovered a difference between the two treatment methods [t(14) = 16.26, p < .0001]. Ultrasound alone increased tissue temperature an average of 2°C, whereas ultrasound preceded by 15 minutes of ice did not increase tissue temperature even to the original baseline level. We concluded that, at a depth of 3 cm, ultrasound alone provided a greater heating effect than ultrasound preceded by an ice treatment. PMID:16558295

Sensorimotor state of the contralateral leg affects ipsilateral muscle coordination of pedaling.

PubMed

Ting, L H; Raasch, C C; Brown, D A; Kautz, S A; Zajac, F E

1998-09-01

The objective of this study was to determine if independent central pattern generating elements controlling the legs in bipedal and unipedal locomotion is a viable theory for locomotor propulsion in humans. Coordinative coupling of the limbs could then be accomplished through mechanical interactions and ipsilateral feedback control rather than through central interlimb neural pathways. Pedaling was chosen as the locomotor task to study because interlimb mechanics can be significantly altered, as pedaling can be executed with the use of either one leg or two legs (cf. walking) and because the load on the limb can be well-controlled. Subjects pedaled a modified bicycle ergometer in a two-legged (bilateral) and a one-legged (unilateral) pedaling condition. The loading on the leg during unilateral pedaling was designed to be identical to the loading experienced by the leg during bilateral pedaling. This loading was achieved by having a trained human "motor" pedal along with the subject and exert on the opposite crank the torque that the subject's contralateral leg generated in bilateral pedaling. The human "motor" was successful at reproducing each subject's one-leg crank torque. The shape of the motor's torque trajectory was similar to that of subjects, and the amount of work done during extension and flexion was not significantly different. Thus the same muscle coordination pattern would allow subjects to pedal successfully in both the bilateral and unilateral conditions, and the afferent signals from the pedaling leg could be the same for both conditions. Although the overall work done by each leg did not change, an 86% decrease in retarding (negative) crank torque during limb flexion was measured in all 11 subjects during the unilateral condition. This corresponded to an increase in integrated electromyography of tibialis anterior (70%), rectus femoris (43%), and biceps femoris (59%) during flexion. Even given visual torque feedback in the unilateral condition

Cerebral correlates of muscle tone fluctuations in restless legs syndrome: a pilot study with combined functional magnetic resonance imaging and anterior tibial muscle electromyography.

PubMed

Spiegelhalder, Kai; Feige, Bernd; Paul, Dominik; Riemann, Dieter; van Elst, Ludger Tebartz; Seifritz, Erich; Hennig, Jürgen; Hornyak, Magdolna

2008-01-01

The pathology of restless legs syndrome (RLS) is still not understood. To investigate the pathomechanism of the disorder further we recorded a surface electromyogram (EMG) of the anterior tibial muscle during functional magnetic resonance imaging (fMRI) in patients with idiopathic RLS. Seven subjects with moderate to severe RLS were investigated in the present pilot study. Patients were lying supine in the scanner for over 50 min and were instructed not to move voluntarily. Sensory leg discomfort (SLD) was evaluated on a 10-point Likert scale. For brain image analysis, an algorithm for the calculation of tonic EMG values was developed. We found a negative correlation of tonic EMG and SLD (p <0.01). This finding provides evidence for the clinical experience that RLS-related subjective leg discomfort increases during muscle relaxation at rest. In the fMRI analysis, the tonic EMG was associated with activation in motor and somatosensory pathways and also in some regions that are not primarily related to motor or somatosensory functions. By using a newly developed algorithm for the investigation of muscle tone-related changes in cerebral activity, we identified structures that are potentially involved in RLS pathology. Our method, with some modification, may also be suitable for the investigation of phasic muscle activity that occurs during periodic leg movements.

A common neural element receiving rhythmic arm and leg activity as assessed by reflex modulation in arm muscles.

PubMed

Sasada, Syusaku; Tazoe, Toshiki; Nakajima, Tsuyoshi; Futatsubashi, Genki; Ohtsuka, Hiroyuki; Suzuki, Shinya; Zehr, E Paul; Komiyama, Tomoyoshi

2016-04-01

Neural interactions between regulatory systems for rhythmic arm and leg movements are an intriguing issue in locomotor neuroscience. Amplitudes of early latency cutaneous reflexes (ELCRs) in stationary arm muscles are modulated during rhythmic leg or arm cycling but not during limb positioning or voluntary contraction. This suggests that interneurons mediating ELCRs to arm muscles integrate outputs from neural systems controlling rhythmic limb movements. Alternatively, outputs could be integrated at the motoneuron and/or supraspinal levels. We examined whether a separate effect on the ELCR pathways and cortico-motoneuronal excitability during arm and leg cycling is integrated by neural elements common to the lumbo-sacral and cervical spinal cord. The subjects performed bilateral leg cycling (LEG), contralateral arm cycling (ARM), and simultaneous contralateral arm and bilateral leg cycling (A&L), while ELCRs in the wrist flexor and shoulder flexor muscles were evoked by superficial radial (SR) nerve stimulation. ELCR amplitudes were facilitated by cycling tasks and were larger during A&L than during ARM and LEG. A low stimulus intensity during ARM or LEG generated a larger ELCR during A&L than the sum of ELCRs during ARM and LEG. We confirmed this nonlinear increase in single motor unit firing probability following SR nerve stimulation during A&L. Furthermore, motor-evoked potentials following transcranial magnetic and electrical stimulation did not show nonlinear potentiation during A&L. These findings suggest the existence of a common neural element of the ELCR reflex pathway that is active only during rhythmic arm and leg movement and receives convergent input from contralateral arms and legs. Copyright © 2016 the American Physiological Society.

Real-Time Classification of Hand Motions Using Ultrasound Imaging of Forearm Muscles.

PubMed

Akhlaghi, Nima; Baker, Clayton A; Lahlou, Mohamed; Zafar, Hozaifah; Murthy, Karthik G; Rangwala, Huzefa S; Kosecka, Jana; Joiner, Wilsaan M; Pancrazio, Joseph J; Sikdar, Siddhartha

2016-08-01

Surface electromyography (sEMG) has been the predominant method for sensing electrical activity for a number of applications involving muscle-computer interfaces, including myoelectric control of prostheses and rehabilitation robots. Ultrasound imaging for sensing mechanical deformation of functional muscle compartments can overcome several limitations of sEMG, including the inability to differentiate between deep contiguous muscle compartments, low signal-to-noise ratio, and lack of a robust graded signal. The objective of this study was to evaluate the feasibility of real-time graded control using a computationally efficient method to differentiate between complex hand motions based on ultrasound imaging of forearm muscles. Dynamic ultrasound images of the forearm muscles were obtained from six able-bodied volunteers and analyzed to map muscle activity based on the deformation of the contracting muscles during different hand motions. Each participant performed 15 different hand motions, including digit flexion, different grips (i.e., power grasp and pinch grip), and grips in combination with wrist pronation. During the training phase, we generated a database of activity patterns corresponding to different hand motions for each participant. During the testing phase, novel activity patterns were classified using a nearest neighbor classification algorithm based on that database. The average classification accuracy was 91%. Real-time image-based control of a virtual hand showed an average classification accuracy of 92%. Our results demonstrate the feasibility of using ultrasound imaging as a robust muscle-computer interface. Potential clinical applications include control of multiarticulated prosthetic hands, stroke rehabilitation, and fundamental investigations of motor control and biomechanics.

Predicting muscle forces during the propulsion phase of single leg triple hop test.

PubMed

Alvim, Felipe Costa; Lucareli, Paulo Roberto Garcia; Menegaldo, Luciano Luporini

2018-01-01

Functional biomechanical tests allow the assessment of musculoskeletal system impairments in a simple way. Muscle force synergies associated with movement can provide additional information for diagnosis. However, such forces cannot be directly measured noninvasively. This study aims to estimate muscle activations and forces exerted during the preparation phase of the single leg triple hop test. Two different approaches were tested: static optimization (SO) and computed muscle control (CMC). As an indirect validation, model-estimated muscle activations were compared with surface electromyography (EMG) of selected hip and thigh muscles. Ten physically healthy active women performed a series of jumps, and ground reaction forces, kinematics and EMG data were recorded. An existing OpenSim model with 92 musculotendon actuators was used to estimate muscle forces. Reflective markers data were processed using the OpenSim Inverse Kinematics tool. Residual Reduction Algorithm (RRA) was applied recursively before running the SO and CMC. For both, the same adjusted kinematics were used as inputs. Both approaches presented similar residuals amplitudes. SO showed a closer agreement between the estimated activations and the EMGs of some muscles. Due to inherent EMG methodological limitations, the superiority of SO in relation to CMC can be only hypothesized. It should be confirmed by conducting further studies comparing joint contact forces. The workflow presented in this study can be used to estimate muscle forces during the preparation phase of the single leg triple hop test and allows investigating muscle activation and coordination. Copyright © 2017 Elsevier B.V. All rights reserved.

Coordinated Development of Muscles and Tendon-Like Structures: Early Interactions in the Drosophila Leg.

PubMed

Soler, Cedric; Laddada, Lilia; Jagla, Krzysztof

2016-01-01

The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton) via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well-established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here, we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates) during the early steps of leg development, we affect the spatial localization of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes.

Coordinated Development of Muscles and Tendon-Like Structures: Early Interactions in the Drosophila Leg

PubMed Central

Soler, Cedric; Laddada, Lilia; Jagla, Krzysztof

2016-01-01

The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton) via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well-established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here, we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates) during the early steps of leg development, we affect the spatial localization of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes. PMID:26869938

Do oarsmen have asymmetries in the strength of their back and leg muscles?

PubMed

Parkin, S; Nowicky, A V; Rutherford, O M; McGregor, A H

2001-07-01

The aim of this study was to establish whether asymmetry of the strength of the leg and trunk musculature is more prominent in rowers than in controls. Nineteen oarsmen and 20 male controls matched for age, height and body mass performed a series of isokinetic and isometric strength tests on an isokinetic dynamometer. These strength tests focused on the trunk and leg muscles. Comparisons of strength were made between and within groups for right and left symmetry patterns, hamstring: quadriceps ratios, and trunk flexor and extensor ratios. The results revealed no left and right asymmetries in either the knee extensor or flexor strength parameters (including both isometric and isokinetic measures). Knee extensor strength was significantly greater in the rowing population, but knee flexor strength was similar between the two groups. No difference was seen between the groups for the hamstring: quadriceps strength ratio. In the rowing population, stroke side had no influence on leg strength. No differences were observed in the isometric strength of the trunk flexors and extensors between groups, although EMG activity was significantly higher in the rowing population. Patterns of asymmetry of muscle activity were observed between the left and right erector spinae muscles during extension, which was significantly related to rowing side (P < 0.01). These observations could be related to the high incidence of low back pain in oarsmen.

Experience with peroneus brevis muscle flaps for reconstruction of distal leg and ankle defects

PubMed Central

Bajantri, Babu; Bharathi, Ravindra; Ramkumar, Sanjai; Latheef, Latheesh; Dhane, Smitha; Sabapathy, S. Raja

2013-01-01

Objective: Peroneus brevis is a muscle in the leg which is expendable without much functional deficit. The objective of this study was to find out its usefulness in coverage of the defects of the lower leg and ankle. Patients and Methods: A retrospective analysis of the use of 39 pedicled peroneus brevis muscle flaps used for coverage of defects of the lower leg and ankle between November 2010 and December 2012 was carried out. The flaps were proximally based for defects of the lower third of the leg in 12 patients and distally based for reconstruction of defects of the ankle in 26 patients, with one patient having flaps on both ankles. Results: Partial flap loss in critical areas was found in four patients requiring further flap cover and in non-critical areas in two patients, which were managed with a skin graft. Three of the four critical losses occurred when we used it for covering defects over the medial malleolus. There was no complete flap loss in any of the patients. Conclusion: This flap has a unique vascular pattern and fails to fit into the classification of the vasculature of muscles by Mathes and Nahai. The unusual feature is an axial vessel system running down the deep aspect of the muscle and linking the perforators from the peroneal artery and anterior tibial artery, which allows it to be raised proximally or distally on a single perforator. The flap is simple to raise and safe for the reconstruction of small-to moderate-sized skin defects of the distal third of the tibia and all parts of the ankle except the medial malleolus, which is too far from the pedicle of the distally based flap. The donor site can be closed primarily to provide a linear scar. The muscle flap thins with time to provide a good result aesthetically at the primary defect. PMID:23960305

Age-related differences in skeletal muscle microvascular response to exercise as detected by contrast-enhanced ultrasound (CEUS)

PubMed Central

Hildebrandt, Wulf; Schwarzbach, Hans; Pardun, Anita; Hannemann, Lena; Bogs, Björn; König, Alexander M.; Mahnken, Andreas H.; Hildebrandt, Olaf; Koehler, Ulrich; Kinscherf, Ralf

2017-01-01

Background Aging involves reductions in exercise total limb blood flow and exercise capacity. We hypothesized that this may involve early age-related impairments of skeletal muscle microvascular responsiveness as previously reported for insulin but not for exercise stimuli in humans. Methods Using an isometric exercise model, we studied the effect of age on contrast-enhanced ultrasound (CEUS) parameters, i.e. microvascular blood volume (MBV), flow velocity (MFV) and blood flow (MBF) calculated from replenishment of Sonovue contrast-agent microbubbles after their destruction. CEUS was applied to the vastus lateralis (VLat) and intermedius (VInt) muscle in 15 middle-aged (MA, 43.6±1.5 years) and 11 young (YG, 24.1±0.6 years) healthy males before, during, and after 2 min of isometric knee extension at 15% of peak torque (PT). In addition, total leg blood flow as recorded by femoral artery Doppler-flow. Moreover, fiber-type-specific and overall capillarisation as well as fiber composition were additionally assessed in Vlat biopsies obtained from CEUS site. MA and YG had similar quadriceps muscle MRT-volume or PT and maximal oxygen uptake as well as a normal cardiovascular risk factors and intima-media-thickness. Results During isometric exercise MA compared to YG reached significantly lower levels in MFV (0.123±0.016 vs. 0.208±0.036 a.u.) and MBF (0.007±0.001 vs. 0.012±0.002 a.u.). In the VInt the (post-occlusive hyperemia) post-exercise peaks in MBV and MBF were significantly lower in MA vs. YG. Capillary density, capillary fiber contacts and femoral artery Doppler were similar between MA and YG. Conclusions In the absence of significant age-related reductions in capillarisation, total leg blood flow or muscle mass, healthy middle-aged males reveal impaired skeletal muscle microcirculatory responses to isometric exercise. Whether this limits isometric muscle performance remains to be assessed. PMID:28273102

Quality properties of pre- and post-rigor beef muscle after interventions with high frequency ultrasound.

PubMed

Sikes, Anita L; Mawson, Raymond; Stark, Janet; Warner, Robyn

2014-11-01

The delivery of a consistent quality product to the consumer is vitally important for the food industry. The aim of this study was to investigate the potential for using high frequency ultrasound applied to pre- and post-rigor beef muscle on the metabolism and subsequent quality. High frequency ultrasound (600kHz at 48kPa and 65kPa acoustic pressure) applied to post-rigor beef striploin steaks resulted in no significant effect on the texture (peak force value) of cooked steaks as measured by a Tenderometer. There was no added benefit of ultrasound treatment above that of the normal ageing process after ageing of the steaks for 7days at 4°C. Ultrasound treatment of post-rigor beef steaks resulted in a darkening of fresh steaks but after ageing for 7days at 4°C, the ultrasound-treated steaks were similar in colour to that of the aged, untreated steaks. High frequency ultrasound (2MHz at 48kPa acoustic pressure) applied to pre-rigor beef neck muscle had no effect on the pH, but the calculated exhaustion factor suggested that there was some effect on metabolism and actin-myosin interaction. However, the resultant texture of cooked, ultrasound-treated muscle was lower in tenderness compared to the control sample. After ageing for 3weeks at 0°C, the ultrasound-treated samples had the same peak force value as the control. High frequency ultrasound had no significant effect on the colour parameters of pre-rigor beef neck muscle. This proof-of-concept study showed no effect of ultrasound on quality but did indicate that the application of high frequency ultrasound to pre-rigor beef muscle shows potential for modifying ATP turnover and further investigation is warranted. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Antagonist muscle co-contraction during a double-leg landing maneuver at two heights.

PubMed

Mokhtarzadeh, Hossein; Yeow, Chen Hua; Goh, James Cho Hong; Oetomo, Denny; Ewing, Katie; Lee, Peter Vee Sin

2017-10-01

Knee injuries are common during landing activities. Greater landing height increases peak ground reaction forces (GRFs) and loading at the knee joint. As major muscles to stabilize the knee joint, Quadriceps and Hamstring muscles provide internal forces to attenuate the excessive GRF. Despite the number of investigations on the importance of muscle function during landing, the role of landing height on these muscles forces using modeling during landing is not fully investigated. Participant-specific musculoskeletal models were developed using experimental motion analysis data consisting of anatomic joint motions and GRF from eight male participants performing double-leg drop landing from 30 and 60 cm. Muscle forces were calculated in OpenSim and their differences were analyzed at the instances of high risk during landing i.e. peak GRF for both heights. The maximum knee flexion angle and moments were found significantly higher from a double-leg landing at 60 cm compared to 30 cm. The results showed elevated GRF, and mean muscle forces during landing. At peak GRF, only quadriceps showed significantly greater forces at 60 cm. Hamstring muscle forces did not significantly change at 60 cm compared to 30 cm. Quadriceps and hamstring muscle forces changed at different heights. Since hamstring forces were similar in both landing heights, this could lead to an imbalance between the antagonist muscles, potentially placing the knee at risk of injury if combined with small flexion angles that was not observed at peak GRF in our study. Thus, enhanced neuromuscular training programs strengthening the hamstrings may be required to address this imbalance. These findings may contribute to enhance neuromuscular training programs to prevent knee injuries during landing.

Body Mass Normalization for Ultrasound Measurements of Adolescent Lateral Abdominal Muscle Thickness.

PubMed

Linek, Pawel; Saulicz, Edward; Wolny, Tomasz; Myśliwiec, Andrzej

2017-04-01

The purpose of this study was to determine the value of the allometric parameter for ultrasound measurements of the thickness of the oblique external (OE), internal (OI), and transversus abdominis (TrA) muscles in the adolescent population. The allometric parameter is the slope of the linear regression line between the log transformed body mass and log transformed muscle size measurement. The study included 321 adolescents between the ages of 10 and 17, consisting of 160 boys and 161 girls. The participants were recruited from local schools and attended regular school classes at normal grade levels. All individuals with no signs of scoliosis (screening with use of a scoliometer), and no surgical procedures performed on the trunk area were included. A real-time ultrasound B-scanner with a linear array transducer was used to obtain images of the lateral abdominal muscles from both sides of the body. The correlation between body mass and the OE muscle was r = 0.69; the OI muscle r = 0.68; and the TrA muscle r = 0.53 (in all cases, P < .0001). The allometric parameter for the OE was 0.88296; the OI 0.718756; and the TrA 0.60986. Using these parameters, no significant correlations were found between body mass and the allometric-scaled thickness of the lateral abdominal muscles. Significant positive correlations exist between body mass and lateral abdominal muscle thickness assessed by ultrasound imaging. Therefore, it is reasonable to advise that the values of the allometric parameters for OE, OI, and TrA obtained in this study should be used in other studies performed on adolescents. © 2016 by the American Institute of Ultrasound in Medicine.

AUGMENTATION OF MUSCLE BLOOD FLOW BY ULTRASOUND CAVITATION IS MEDIATED BY ATP AND PURINERGIC SIGNALING

PubMed Central

Belcik, J. Todd; Davidson, Brian P.; Xie, Aris; Wu, Melinda D.; Yadava, Mrinal; Qi, Yue; Liang, Sherry; Chon, Chae Ryung; Ammi, Azzdine Y.; Field, Joshua; Harmann, Leanne; Chilian, William M.; Linden, Joel; Lindner, Jonathan R.

2017-01-01

Background Augmentation of tissue blood flow by therapeutic ultrasound is thought to rely on convective shear. Microbubble contrast agents that undergo ultrasound-mediated cavitation markedly amplify these effects. We hypothesized that purinergic signalling is responsible for shear-dependent increases in muscle perfusion during therapeutic cavitation. Methods Unilateral exposure of the proximal hindlimb of mice (with or without ischemia produced by iliac ligation) to therapeutic ultrasound (1.3 MHz, mechanical index 1.3) was performed for ten minutes after intravenous injection of 2×108 lipid microbubbles. Microvascular perfusion was evaluated by low-power contrast ultrasound perfusion imaging. In vivo muscle ATP release and in vitro ATP release from endothelial cells or erythrocytes were assessed by a luciferin-luciferase assay. Purinergic signalling pathways were assessed by studying interventions that either (1) accelerated ATP degradation; (2) inhibited P2Y receptors, adenosine receptors, or KATP channels; or (3) inhibited downstream signalling pathways involving endothelial nitric oxide synthase (eNOS) or prostanoid production (indomethacin). Augmentation in muscle perfusion by ultrasound cavitation was assessed in a proof-of-concept clinical trial in 12 subjects with stable sickle cell disease (SCD). Results Therapeutic ultrasound cavitation increased muscle perfusion by 7-fold in normal mice, reversed tissue ischemia for up to 24 hrs in the murine model of peripheral artery disease, and doubled muscle perfusion in patients with SCD. Augmentation in flow extended well beyond the region of ultrasound exposure. Ultrasound cavitation produced a nearly 40-fold focal and sustained increase in ATP, the source of which included both endothelial cells and erythrocytes. Inhibitory studies indicated that ATP was a critical mediator of flow augmentation that acts primarily through either P2Y receptors or through adenosine produced by ectonucleotidase activity. Combined

Augmentation of Muscle Blood Flow by Ultrasound Cavitation Is Mediated by ATP and Purinergic Signaling.

PubMed

Belcik, J Todd; Davidson, Brian P; Xie, Aris; Wu, Melinda D; Yadava, Mrinal; Qi, Yue; Liang, Sherry; Chon, Chae Ryung; Ammi, Azzdine Y; Field, Joshua; Harmann, Leanne; Chilian, William M; Linden, Joel; Lindner, Jonathan R

2017-03-28

Augmentation of tissue blood flow by therapeutic ultrasound is thought to rely on convective shear. Microbubble contrast agents that undergo ultrasound-mediated cavitation markedly amplify these effects. We hypothesized that purinergic signaling is responsible for shear-dependent increases in muscle perfusion during therapeutic cavitation. Unilateral exposure of the proximal hindlimb of mice (with or without ischemia produced by iliac ligation) to therapeutic ultrasound (1.3 MHz, mechanical index 1.3) was performed for 10 minutes after intravenous injection of 2×10 8 lipid microbubbles. Microvascular perfusion was evaluated by low-power contrast ultrasound perfusion imaging. In vivo muscle ATP release and in vitro ATP release from endothelial cells or erythrocytes were assessed by a luciferin-luciferase assay. Purinergic signaling pathways were assessed by studying interventions that (1) accelerated ATP degradation; (2) inhibited P2Y receptors, adenosine receptors, or K ATP channels; or (3) inhibited downstream signaling pathways involving endothelial nitric oxide synthase or prostanoid production (indomethacin). Augmentation in muscle perfusion by ultrasound cavitation was assessed in a proof-of-concept clinical trial in 12 subjects with stable sickle cell disease. Therapeutic ultrasound cavitation increased muscle perfusion by 7-fold in normal mice, reversed tissue ischemia for up to 24 hours in the murine model of peripheral artery disease, and doubled muscle perfusion in patients with sickle cell disease. Augmentation in flow extended well beyond the region of ultrasound exposure. Ultrasound cavitation produced an ≈40-fold focal and sustained increase in ATP, the source of which included both endothelial cells and erythrocytes. Inhibitory studies indicated that ATP was a critical mediator of flow augmentation that acts primarily through either P2Y receptors or adenosine produced by ectonucleotidase activity. Combined indomethacin and inhibition of

Muscle Activity in Single- vs. Double-Leg Squats.

PubMed

DeFOREST, Bradley A; Cantrell, Gregory S; Schilling, Brian K

Muscular activity, vertical displacement and ground reaction forces of back squats (BS), rear-leg elevated split squats (RLESS) and split squats (SS) were examined. Nine resistance-trained men reported for two sessions. The first session consisted of the consent process, practice, and BS 1-repetition maximum testing. In the second session, participants performed the three exercises while EMG, displacment and ground reaction force data (one leg on plate) were collected. EMG data were collected from the gluteus maximus (GMX), biceps femoris (BF), semitendinosus (ST), rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), tibialis anterior (TA), and medial gastrocnemius (MGas) of the left leg (non-dominant, front leg for unilateral squats). Load for BS was 85% one repetition maximum, and RLESS and SS were performed at 50% of BS load. Repeated measures ANOVA was used to compare all variables for the three exercises, with Bonferroni adjustments for post hoc multiple comparisons, in addition to calculation of standardized mean differences (ES). Muscle activity was similar between exercises except for biceps femoris, which was significantly higher during RLESS than SS during both concentric and eccentric phases (ES = 2.11; p=0.012 and ES= 2.19; p=0.008), and significantly higher during BS than the SS during the concentric phase (ES = 1.78; p=0.029). Vertical displacement was similar between all exercises. Peak vertical force was similar between BS and RLESS and significantly greater during RLESS than SS (ES = 3.03; p=0.001). These findings may be helpful in designing resistance training programs by using RLESS if greater biceps femoris activity is desired.

Muscle Activity in Single- vs. Double-Leg Squats

PubMed Central

DeFOREST, BRADLEY A.; CANTRELL, GREGORY S.; SCHILLING, BRIAN K.

2014-01-01

Muscular activity, vertical displacement and ground reaction forces of back squats (BS), rear-leg elevated split squats (RLESS) and split squats (SS) were examined. Nine resistance-trained men reported for two sessions. The first session consisted of the consent process, practice, and BS 1-repetition maximum testing. In the second session, participants performed the three exercises while EMG, displacment and ground reaction force data (one leg on plate) were collected. EMG data were collected from the gluteus maximus (GMX), biceps femoris (BF), semitendinosus (ST), rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), tibialis anterior (TA), and medial gastrocnemius (MGas) of the left leg (non-dominant, front leg for unilateral squats). Load for BS was 85% one repetition maximum, and RLESS and SS were performed at 50% of BS load. Repeated measures ANOVA was used to compare all variables for the three exercises, with Bonferroni adjustments for post hoc multiple comparisons, in addition to calculation of standardized mean differences (ES). Muscle activity was similar between exercises except for biceps femoris, which was significantly higher during RLESS than SS during both concentric and eccentric phases (ES = 2.11; p=0.012 and ES= 2.19; p=0.008), and significantly higher during BS than the SS during the concentric phase (ES = 1.78; p=0.029). Vertical displacement was similar between all exercises. Peak vertical force was similar between BS and RLESS and significantly greater during RLESS than SS (ES = 3.03; p=0.001). These findings may be helpful in designing resistance training programs by using RLESS if greater biceps femoris activity is desired. PMID:27182408

The effects of performing a one-legged bridge with hip abduction and use of a sling on trunk and lower extremity muscle activation in healthy adults.

PubMed

Choi, Kyuju; Bak, Jongwoo; Cho, Minkwon; Chung, Yijung

2016-09-01

[Purpose] This study investigated the changes in the muscle activities of the trunk and lower limbs of healthy adults during a one-legged bridge exercise using a sling, and with the addition of hip abduction. [Subjects and Methods] Twenty-seven healthy individuals participated in this study (14 males and 13 females). The participants were instructed to perform the bridge exercises under five different conditions. Trunk and lower limb muscle activation of the erector spinae (ES), external oblique (EO), gluteus maximus (GM), and biceps femoris (BF) was measured using surface electromyography. Data analysis was performed using the mean scores of three trials performed under each condition. [Results] There was a significant increase in bilateral EO and contralateral GM with the one-legged bridge compared with the one-legged bridge with sling exercise. Muscle activation of the ipsilateral GM and BF was significantly less during the one-legged bridge exercise compared to the one-legged bridge with sling exercise, and was significantly greater during the one-legged bridge with hip abduction compared to the one-legged bridge exercise. The muscle activation of the contralateral GM and BF was significantly greater with the one-legged bridge with hip abduction compared to the general bridge exercise. [Conclusion] With the one-legged bridge with hip abduction, the ipsilateral EO, GM and BF muscle activities were significantly greater than those of the one-legged bridge exercise. The muscle activation of all trunk and contralateral lower extremity muscles increased with the bridge with sling exercises compared with general bridge exercises.

The effects of passive leg press training on jumping performance, speed, and muscle power.

PubMed

Liu, Chiang; Chen, Chuan-Shou; Ho, Wei-Hua; Füle, Róbert János; Chung, Pao-Hung; Shiang, Tzyy-Yuang

2013-06-01

Passive leg press (PLP) training was developed based on the concepts of the stretch-shortening cycle (SSC) and the benefits of high muscle contraction velocity. Passive leg press training enables lower limb muscle groups to apply a maximum downward force against a platform moved up and down at high frequency by an electric motor. Thus, these muscle groups accomplished both concentric and eccentric isokinetic contractions in a passive, rapid, and repetitive manner. This study investigates the effects of 10 weeks of PLP training at high and low movement frequencies have on jumping performance, speed, and muscle power. The authors selected 30 college students who had not performed systematic resistance training in the previous 6 months, including traditional resistance training at a squat frequency of 0.5 Hz, PLP training at a low frequency of 0.5 Hz, and PLP training at a high frequency of 2.5 Hz, and randomly divided them into 3 groups (n = 10). The participants' vertical jump, drop jump, 30-m sprint performance, explosive force, and SSC efficiency were tested under the same experimental procedures at pre- and post-training. Results reveal that high-frequency PLP training significantly increased participants' vertical jump, drop jump, 30-m sprint performance, instantaneous force, peak power, and SSC efficiency (p < 0.05). Additionally, their change rate abilities were substantially superior to those of the traditional resistance training (p < 0.05). The low-frequency PLP training significantly increased participants' vertical jump, 30-m sprint performance, instantaneous force, and peak power (p < 0.05). However, traditional resistance training only increased participants' 30-m sprint performance and peak power (p < 0.05). The findings suggest that jump performance, speed, and muscle power significantly improved after 10 weeks of PLP training at high movement frequency. A PLP training machine powered by an electrical motor enables muscles of the lower extremities to

The use of real-time ultrasound imaging for biofeedback of lumbar multifidus muscle contraction in healthy subjects.

PubMed

Van, Khai; Hides, Julie A; Richardson, Carolyn A

2006-12-01

Randomized controlled trial. To determine if the provision of visual biofeedback using real-time ultrasound imaging enhances the ability to activate the multifidus muscle. Increasingly clinicians are using real-time ultrasound as a form of biofeedback when re-educating muscle activation. The effectiveness of this form of biofeedback for the multifidus muscle has not been reported. Healthy subjects were randomly divided into groups that received different forms of biofeedback. All subjects received clinical instruction on how to activate the multifidus muscle isometrically prior to testing and verbal feedback regarding the amount of multifidus contraction, which occurred during 10 repetitions (acquisition phase). In addition, 1 group received visual biofeedback (watched the multifidus muscle contract) using real-time ultrasound imaging. All subjects were reassessed a week later (retention phase). Subjects from both groups improved their voluntary contraction of the multifidus muscle in the acquisition phase (P<.001) and the ability to recruit the multifidus muscle differed between groups (P<.05), with subjects in the group that received visual ultrasound biofeedback achieving greater improvements. In addition, the group that received visual ultrasound biofeedback retained their improvement in performance from week 1 to week 2 (P>.90), whereas the performance of the other group decreased (P<.05). Real-time ultrasound imaging can be used to provide visual biofeedback and improve performance and retention in the ability to activate the multifidus muscle in healthy subjects.

A neuro-mechanical model of a single leg joint highlighting the basic physiological role of fast and slow muscle fibres of an insect muscle system.

PubMed

Toth, Tibor Istvan; Schmidt, Joachim; Büschges, Ansgar; Daun-Gruhn, Silvia

2013-01-01

In legged animals, the muscle system has a dual function: to produce forces and torques necessary to move the limbs in a systematic way, and to maintain the body in a static position. These two functions are performed by the contribution of specialized motor units, i.e. motoneurons driving sets of specialized muscle fibres. With reference to their overall contraction and metabolic properties they are called fast and slow muscle fibres and can be found ubiquitously in skeletal muscles. Both fibre types are active during stepping, but only the slow ones maintain the posture of the body. From these findings, the general hypothesis on a functional segregation between both fibre types and their neuronal control has arisen. Earlier muscle models did not fully take this aspect into account. They either focused on certain aspects of muscular function or were developed to describe specific behaviours only. By contrast, our neuro-mechanical model is more general as it allows functionally to differentiate between static and dynamic aspects of movement control. It does so by including both muscle fibre types and separate motoneuron drives. Our model helps to gain a deeper insight into how the nervous system might combine neuronal control of locomotion and posture. It predicts that (1) positioning the leg at a specific retraction angle in steady state is most likely due to the extent of recruitment of slow muscle fibres and not to the force developed in the individual fibres of the antagonistic muscles; (2) the fast muscle fibres of antagonistic muscles contract alternately during stepping, while co-contraction of the slow muscle fibres takes place during steady state; (3) there are several possible ways of transition between movement and steady state of the leg achieved by varying the time course of recruitment of the fibres in the participating muscles.

Acute experimental hip muscle pain alters single-leg squat balance in healthy young adults.

PubMed

Hatton, Anna L; Crossley, Kay M; Hug, François; Bouma, James; Ha, Bonnie; Spaulding, Kara L; Tucker, Kylie

2015-05-01

Clinical musculoskeletal pain commonly accompanies hip pathology and can impact balance performance. Due to the cross-sectional designs of previous studies, and the multifactorial nature of musculoskeletal pain conditions, it is difficult to determine whether pain is a driver of balance impairments in this population. This study explored the effects of experimentally induced hip muscle pain on static and dynamic balance. Twelve healthy adults (4 women, mean[SD]: 27.1[3] years) performed three balance tasks on each leg, separately: single-leg standing (eyes closed), single-leg squat (eyes open), forward step (eyes open); before and after hypertonic saline injection (1ml, 5% NaCl) into the right gluteus medius. Range, standard deviation (SD), and velocity of the centre of pressure (CoP) in medio-lateral (ML) and anterior-posterior (AP) directions were considered. During the single-leg squat task, experimental hip pain was associated with significantly reduced ML range (-4[13]%, P=0.028), AP range (-14[21]%, P=0.005), APSD (-15[28]%, P=0.009), and AP velocity (-6[13]%, P=0.032), relative to the control condition, in both legs. No effect of pain was observed during single-leg standing and forward stepping. Significant between-leg differences in ML velocity were observed during the forward stepping task (P=0.034). Pain is a potentially modifiable patient-reported outcome in individuals with hip problems. This study demonstrates that acute hip muscle pain alone, without interference of musculoskeletal pathology, does not lead to the same impairments in balance as exhibited in clinical populations with hip pathologies. This is the first step in understanding how and why balance is altered in painful hip pathologies. Copyright © 2015 Elsevier B.V. All rights reserved.

Coactivation of lower leg muscles during body weight-supported treadmill walking decreases with age in adolescents.

PubMed

Deffeyes, Joan E; Karst, Gregory M; Stuberg, Wayne A; Kurz, Max J

2012-08-01

The kinematics of children's walking are nearly adult-like by about age 3-4 years, but metabolic efficiency of walking does not reach adult values until late in adolescence or early adulthood, perhaps due to higher coactivation of agonist/antagonist muscle pairs in adolescents. Additionally, it is unknown how use of a body weight-supported treadmill device affects coactivation, but because unloading will alter the activity of anti-gravity muscles, it was hypothesized that muscle coactivation will be altered as well. Muscle coactivation during treadmill walking was evaluated for adolescents (ages 10 to 17 years, M = 13.2, SD = 2.2) and adults (ages 22 to 35 years, M = 25.2, SD = 4.3), for thigh muscles (vastus lateralis/biceps femoris) and lower leg muscles (tibialis anterior/gastrocnemius). Conditions included body weight unloadings from nearly 0% to 80% of body weight, while walking at a preferred speed (self-selected, overground speed) or a reduced speed. Unloading was accomplished using a lower body positive pressure support system. Coactivation was found to be higher in adolescents than in adults, but only for the lower leg muscles.

Characteristics of Lower Leg Muscle Activity in Patients with Cerebral Palsy during Cycling on an Ergometer.

PubMed

Roy, Susmita; Alves-Pinto, Ana; Lampe, Renée

2018-01-01

Cycling on ergometer is often part of rehabilitation programs for patients with cerebral palsy (CP). The present study analyzed activity patterns of individual lower leg muscle during active cycling on ergometer in patients with CP and compared them to similar recordings in healthy participants. Electromyographic (EMG) recordings of lower leg muscle activity were collected from 14 adult patients and 10 adult healthy participants. Activity of the following muscles was recorded: Musculus tibialis anterior, Musculus gastrocnemius, Musculus rectus femoris, and Musculus biceps femoris. Besides qualitative analysis also quantitative analysis of individual muscle activity was performed by computing the coefficient of variation of EMG signal amplitude. More irregular EMG patterns were observed in patients in comparison to healthy participants: agonist-antagonist cocontractions were more frequent, muscle activity measured at specific points of the cycle path was more variable, and dynamic range of muscle activity along the cycle path was narrower in patients. Hypertonicity was also more frequent in patients. Muscle activity patterns during cycling differed substantially across patients. It showed irregular nature and occasional sharp high peaks. Dynamic range was also narrower than in controls. Observations underline the need for individualized cycling training to optimize rehabilitation effects.

FE6 during Sprint Ultrasound Scans

NASA Image and Video Library

2013-11-22

ISS038-E-007119 (21 Nov. 2013) --- Japan Aerospace Exploration Agency astronaut Koichi Wakata, Expedition 38 flight engineer, wears ultrasound gear around his legs while performing the Integrated Resistance and Aerobic Training Study (Sprint) experiment in the Columbus laboratory of the International Space Station. Sprint evaluates the use of high intensity, low volume exercise training to minimize loss of muscle, bone, and cardiovascular function in station crew members during long-duration missions.

Influence of respiratory muscle work on VO(2) and leg blood flow during submaximal exercise.

PubMed

Wetter, T J; Harms, C A; Nelson, W B; Pegelow, D F; Dempsey, J A

1999-08-01

The work of breathing (W(b)) normally incurred during maximal exercise not only requires substantial cardiac output and O(2) consumption (VO(2)) but also causes vasoconstriction in locomotor muscles and compromises leg blood flow (Q(leg)). We wondered whether the W(b) normally incurred during submaximal exercise would also reduce Q(leg). Therefore, we investigated the effects of changing the W(b) on Q(leg) via thermodilution in 10 healthy trained male cyclists [maximal VO(2) (VO(2 max)) = 59 +/- 9 ml. kg(-1). min(-1)] during repeated bouts of cycle exercise at work rates corresponding to 50 and 75% of VO(2 max). Inspiratory muscle work was 1) reduced 40 +/- 6% via a proportional-assist ventilator, 2) not manipulated (control), or 3) increased 61 +/- 8% by addition of inspiratory resistive loads. Increasing the W(b) during submaximal exercise caused VO(2) to increase; decreasing the W(b) was associated with lower VO(2) (DeltaVO(2) = 0.12 and 0.21 l/min at 50 and 75% of VO(2 max), respectively, for approximately 100% change in W(b)). There were no significant changes in leg vascular resistance (LVR), norepinephrine spillover, arterial pressure, or Q(leg) when W(b) was reduced or increased. Why are LVR, norepinephrine spillover, and Q(leg) influenced by the W(b) at maximal but not submaximal exercise? We postulate that at submaximal work rates and ventilation rates the normal W(b) required makes insufficient demands for VO(2) and cardiac output to require any cardiovascular adjustment and is too small to activate sympathetic vasoconstrictor efferent output. Furthermore, even a 50-70% increase in W(b) during submaximal exercise, as might be encountered in conditions where ventilation rates and/or inspiratory flow resistive forces are higher than normal, also does not elicit changes in LVR or Q(leg).

The susceptibility of the knee extensors to eccentric exercise-induced muscle damage is not affected by leg dominance but by exercise order.

PubMed

Hody, S; Rogister, B; Leprince, P; Laglaine, T; Croisier, J-L

2013-09-01

The aims of this study were first to compare the response of dominant and non-dominant legs to eccentric exercise and second, to examine whether there is an effect of exercise order on the magnitude of symptoms associated with intense eccentric protocols. Eighteen young men performed three sets of 30 maximal eccentric isokinetic (60° s(-1)) contractions of the knee extensors (range of motion, ROM: 0°-100°, 0 = full extension) using either dominant or non-dominant leg. They repeated a similar eccentric bout using the contralateral leg 6 weeks later. The sequence of leg's use was allocated to create equally balanced groups. Four indirect markers of muscle damage including subjective pain intensity, maximal isometric strength, muscle stiffness and plasma creatine kinase (CK) activity were measured before and 24 h after exercise. All markers changed significantly following the eccentric bout performed either by dominant or non-dominant legs, but no significant difference was observed between legs. Interestingly, the comparison between the first and second eccentric bouts revealed that muscle soreness (-42%, P<0.001), CK activity (-62%, P<0.05) and strength loss (-54%, P<0.01) were significantly lower after the second bout. This study suggests that leg dominance does not influence the magnitude of exercise-induced muscle damage and supports for the first time the existence of a contralateral protection against exercise-induced muscle damage in the lower limbs. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Skeletal Muscle Ultrasound in Critical Care: A Tool in Need of Translation.

PubMed

Mourtzakis, Marina; Parry, Selina; Connolly, Bronwen; Puthucheary, Zudin

2017-10-01

With the emerging interest in documenting and understanding muscle atrophy and function in critically ill patients and survivors, ultrasonography has transformational potential for measurement of muscle quantity and quality. We discuss the importance of quantifying skeletal muscle in the intensive care unit setting. We also identify the merits and limitations of various modalities that are capable of accurately and precisely measuring muscularity. Ultrasound is emerging as a potentially powerful tool for skeletal muscle quantification; however, there are key challenges that need to be addressed in future work to ensure useful interpretation and comparability of results across diverse observational and interventional studies. Ultrasound presents several methodological challenges, and ultimately muscle quantification combined with metabolic, nutritional, and functional markers will allow optimal patient assessment and prognosis. Moving forward, we recommend that publications include greater detail on landmarking, repeated measures, identification of muscle that was not assessable, and reproducible protocols to more effectively compare results across different studies.

Relationships Between Lower-Body Muscle Structure and, Lower-Body Strength, Explosiveness and Eccentric Leg Stiffness in Adolescent Athletes

PubMed Central

Secomb, Josh L.; Nimphius, Sophia; Farley, Oliver R.L.; Lundgren, Lina E.; Tran, Tai T.; Sheppard, Jeremy M.

2015-01-01

The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a countermovement jump (CMJ) and squat jump (SJ), and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23) and female (n = 7) surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg) undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isometric mid-thigh pull (IMTP). In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73) were identified between the thickness of the vastus lateralis (VL) and lateral gastrocnemius (LG) muscles, and VL pennation angle and; peak force (PF) in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59) were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59) also present with IMTP PF. These results suggest that greater thickness of the VL and LG were related to improved maximal dynamic and isometric strength, likely due to increased hypertrophy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle. Key points Greater thickness of the VL and LG muscles were significantly related to an enhanced ability to express higher levels of isometric and dynamic strength, and explosiveness in adolescent athletes. Isometric strength underpinned performance in the CMJ and SJ in these athletes. Greater lower-body isometric strength was significantly related to eccentric leg stiffness, which is potentially the result of greater neuromuscular activation in the muscle-tendon unit. PMID

Glucose uptake heterogeneity of the leg muscles is similar between patients with multiple sclerosis and healthy controls during walking.

PubMed

Kindred, John H; Ketelhut, Nathaniel B; Rudroff, Thorsten

2015-02-01

Difficulties in ambulation are one of the main problems reported by patients with multiple sclerosis. A previous study by our research group showed increased recruitment of muscle groups during walking, but the influence of skeletal muscle properties, such as muscle fiber activity, has not been fully elucidated. The purpose of this investigation was to use the novel method of calculating glucose uptake heterogeneity in the leg muscles of patients with multiple sclerosis and compare these results to healthy controls. Eight patients with multiple sclerosis (4 men) and 8 healthy controls (4 men) performed 15 min of treadmill walking at a comfortable self-selected speed following muscle strength tests. Participants were injected with ≈ 8 mCi of [(18)F]-fluorodeoxyglucose during walking after which positron emission tomography/computed tomography imaging was performed. No differences in muscle strength were detected between multiple sclerosis and control groups (P>0.27). Within the multiple sclerosis, group differences in muscle volume existed between the stronger and weaker legs in the vastus lateralis, semitendinosus, and semimembranosus (P<0.03). Glucose uptake heterogeneity between the groups was not different for any muscle group or individual muscle of the legs (P>0.16, P≥0.05). Patients with multiple sclerosis and healthy controls showed similar muscle fiber activity during walking. Interpretations of these results, with respect to our previous study, suggest that walking difficulties in patients with multiple sclerosis may be more associated with altered central nervous system motor patterns rather than alterations in skeletal muscle properties. Published by Elsevier Ltd.

Magnetic Resonance Assessment of Hypertrophic and Pseudo-Hypertrophic Changes in Lower Leg Muscles of Boys with Duchenne Muscular Dystrophy and Their Relationship to Functional Measurements.

PubMed

Vohra, Ravneet S; Lott, Donovan; Mathur, Sunita; Senesac, Claudia; Deol, Jasjit; Germain, Sean; Bendixen, Roxanna; Forbes, Sean C; Sweeney, H Lee; Walter, Glenn A; Vandenborne, Krista

2015-01-01

The primary objectives of this study were to evaluate contractile and non-contractile content of lower leg muscles of boys with Duchenne muscular dystrophy (DMD) and determine the relationships between non-contractile content and functional abilities. Lower leg muscles of thirty-two boys with DMD and sixteen age matched unaffected controls were imaged. Non-contractile content, contractile cross sectional area and non-contractile cross sectional area of lower leg muscles (tibialis anterior, extensor digitorum longus, peroneal, medial gastrocnemius and soleus) were assessed by magnetic resonance imaging (MRI). Muscle strength, timed functional tests and the Brooke lower extremity score were also assessed. Non-contractile content of lower leg muscles (peroneal, medial gastrocnemius, and soleus) was significantly greater than control group (p<0.05). Non-contractile content of lower leg muscles correlated with Brooke score (rs = 0.64-0.84) and 30 feet walk (rs = 0.66-0.80). Dorsiflexor (DF) and plantarflexor (PF) specific torque was significantly different between the groups. Overall, non-contractile content of the lower leg muscles was greater in DMD than controls. Furthermore, there was an age dependent increase in contractile content in the medial gastrocnemius of boys with DMD. The findings of this study suggest that T1 weighted MR images can be used to monitor disease progression and provide a quantitative estimate of contractile and non-contractile content of tissue in children with DMD.

The effects of surface condition on abdominal muscle activity during single-legged hold exercise.

PubMed

Ha, Sung-min; Oh, Jae-seop; Jeon, In-cheol; Kwon, Oh-yun

2015-02-01

To treat low-back pain, various spinal stability exercises are commonly used to improve trunk muscle function and strength. Because human movement for normal daily activity occurs in multi-dimensions, the importance of exercise in multi-dimensions or on unstable surfaces has been emphasized. Recently, a motorized rotating platform (MRP) for facilitating multi-dimensions dynamic movement was introduced for clinical use. However, the abdominal muscle activity with this device has not been reported. The purpose of this study was to compare the abdominal muscle activity (rectus abdominis, external and internal oblique muscles) during an active single-leg-hold (SLH) exercise on a floor (stable surface), foam roll, and motorized rotating platform (MRP). Thirteen healthy male subjects participated in this study. Using electromyography, the abdominal muscle activity was measured while the subjects performed SLH exercises on floor (stable surface), foam roll, and MRP. There were significant differences in the abdominal muscle activities among conditions (P<.05), except for left EO (P>.05) (Fig. 2). After the Bonferroni correction, however, no significant differences among conditions remained, except for differences in both side IO muscle activity between the floor and foam roll conditions (padj<0.017). The findings suggest that performing the SLH exercises on a foam roll and MRP is more effective increased activities of both side of RA and IO, and Rt. EO compared to floor condition. However, there were no significant differences in abdominal muscles activity in the multiple comparison between conditions (mean difference were smaller than the standard deviation in the abdominal muscle activities) (padj>0.017), except for differences in both side IO muscle activity between the floor (stable surface) and foam roll (padj<0.017) (effect size: 0.79/0.62 (non-supporting/supporting leg) for foam-roll versus floor). Copyright © 2014 Elsevier Ltd. All rights reserved.

A Neuro-Mechanical Model Explaining the Physiological Role of Fast and Slow Muscle Fibres at Stop and Start of Stepping of an Insect Leg

PubMed Central

Toth, Tibor Istvan; Grabowska, Martyna; Schmidt, Joachim; Büschges, Ansgar; Daun-Gruhn, Silvia

2013-01-01

Stop and start of stepping are two basic actions of the musculo-skeletal system of a leg. Although they are basic phenomena, they require the coordinated activities of the leg muscles. However, little is known of the details of how these activities are generated by the interactions between the local neuronal networks controlling the fast and slow muscle fibres at the individual leg joints. In the present work, we aim at uncovering some of those details using a suitable neuro-mechanical model. It is an extension of the model in the accompanying paper and now includes all three antagonistic muscle pairs of the main joints of an insect leg, together with their dedicated neuronal control, as well as common inhibitory motoneurons and the residual stiffness of the slow muscles. This model enabled us to study putative processes of intra-leg coordination during stop and start of stepping. We also made use of the effects of sensory signals encoding the position and velocity of the leg joints. Where experimental observations are available, the corresponding simulation results are in good agreement with them. Our model makes detailed predictions as to the coordination processes of the individual muscle systems both at stop and start of stepping. In particular, it reveals a possible role of the slow muscle fibres at stop in accelerating the convergence of the leg to its steady-state position. These findings lend our model physiological relevance and can therefore be used to elucidate details of the stop and start of stepping in insects, and perhaps in other animals, too. PMID:24278108

Focal vibration of quadriceps muscle enhances leg power and decreases knee joint laxity in female volleyball players.

PubMed

Brunetti, O; Botti, F M; Roscini, M; Brunetti, A; Panichi, R; Filippi, G M; Biscarini, A; Pettorossi, V E

2012-12-01

This double-blind randomized controlled study aims at determining the effect of repeated muscle vibration (rMV) on explosive and reactive leg power and on knee laxity of female volleyball players. Eighteen voluntary volleyball athletes, belonging to the same senior regional level team (age=22.7 ± 3 years, height=180.3 ± 5 cm, mass= 64 ± 4 kg) were assigned to three groups (N.=6) for vibration on contracted quadriceps (VC), vibration on relaxed muscle (VR), and sham vibration (NV), respectively. Intervention consisted in 3 rMV sessions performed in 3 consecutive days. In each session, 100 Hz, 300-500 μm amplitude vibratory stimuli were bilaterally delivered to the quadriceps in three consecutive 10-minutes applications. Explosive and reactive leg power and knee joint laxity were evaluated 1 day before, and 1, 30, and 240 days after intervention. In VC group, explosive and reactive leg power increased respectively by ~16% and ~9% at 1 day, by ~19% and ~11% at 30 days and by ~26% and ~13% at 240 days, concomitantly knee laxity decreased by ~6%, ~15% and ~18% at the same times. These changes were significantly larger than in the other groups, in which leg power increment and knee joint laxity reduction remained close to ~3%, ~5% and ~10% at 1, 30 and 240 days, respectively. Combined bilateral voluntary contraction and rMV of the quadriceps muscles is a short-lasting, non-invasive technique that can significantly and persistently improve muscle performance and knee laxity in volleyball women players.

[Contrast-enhanced Ultrasound in Diagnostic Imaging of Muscle Injuries: Perfusion Imaging in the Early Arterial Phase].

PubMed

Hotfiel, T; Carl, H D; Swoboda, B; Engelhardt, M; Heinrich, M; Strobel, D; Wildner, D

2016-03-01

Ultrasound is a standard procedure widely used in the diagnostic investigation of muscle injuries and widely described in the literature. Its advantages include rapid availability, cost effectiveness and the possibility to perform a real-time dynamic examination with the highest possible spatial resolution. In the diagnostic work-up of minor lesions (muscle stiffness, muscle strain), plain ultrasound has so far been inferior to MRI. The case presented by us is an example of the possibilities offered by contrast-enhanced ultrasound (CEUS) in the imaging of muscle injuries compared with plain B-mode image ultrasound and MRI imaging of the affected region. This case report is about a high-performance football player who sustained a muscle injury. He underwent an ultrasound examination (S 2000, 9L4 Probe, Siemens, Germany), which was performed simultaneously in the conventional and contrast-enhanced mode at the level of the lesion. An intravenous bolus injection of 4.8 ml of intravascular contrast agent (SonoVue(®), Bracco, Italy) was given via a cubital intravenous line. After that, the distribution of contrast agent was visualised in the early arterial phase. In addition, a plain magnetic resonance imaging scan of both thighs was performed for reference. On conventional ultrasound, the lesion was not clearly distinguishable from neighbouring tissue, whereas contrast-enhanced ultrasound demonstrated a well delineated, circumscribed area of impaired perfusion with hypoenhancement compared with the surrounding muscles at the clinical level of the lesion in the arterial wash-in phase (0-30 sec, after intravenous administration). The MRI scan revealed an edema signal with perifascial fluid accumulation in the corresponding site. The use of intravascular contrast agent enabled the sensitive detection of a minor injury by ultrasound for the first time. An intramuscular edema seen in the MRI scan showed a functional arterial perfusion impairment on ultrasound, which was

Contrast-Enhanced Ultrasound as a New Investigative Tool in Diagnostic Imaging of Muscle Injuries-A Pilot Study Evaluating Conventional Ultrasound, CEUS, and Findings in MRI.

PubMed

Hotfiel, Thilo; Heiss, Rafael; Swoboda, Bernd; Kellermann, Marion; Gelse, Kolja; Grim, Casper; Strobel, Deike; Wildner, Dane

2018-07-01

To emphasize the diagnostic value of contrast-enhanced ultrasound (CEUS) in the imaging of muscle injuries with different degrees of severity by comparing findings to established imaging modalities such as conventional ultrasound and magnetic resonance imaging (MRI). Case series. Institutional study. Conventional ultrasound and CEUS were performed in the Department of Internal Medicine. Magnetic resonance imaging was carried out in the Department of Radiology within the Magnetom Avanto 1.5T and Magnetom Skyra fit 3T (Siemens Healthineers, Erlangen, Germany) and in the Institution of Imaging Diagnostics and Therapy (Magnetom Avanto 1.5T; Siemens, Erlangen, Germany). Fifteen patients who underwent an acute muscle injury were recruited. The appearance and detectable size of muscle injuries were compared between each imaging modality. The injuries were assessed by 3 independent observers and blinded between imaging modalities. All 15 injuries were identified on MRI and CEUS, whereas 10 injuries showed abnormalities in conventional ultrasound. The determination and measurement revealed significant differences between conventional ultrasound and CEUS depending on injury severity. Contrast-enhanced ultrasound revealed an impairment of microcirculation in grade I lesions (corresponding to intramuscular edema observed in MRI), which was not detectable using conventional ultrasound. Our results indicate that performing CEUS seems to be a sensitive additional diagnostic modality in the early assessment of muscle injuries. Our results highlight the advantages of CEUS in the imaging of low-grade lesions when compared with conventional ultrasound, as this was the more accurate modality for identifying intramuscular edema.

The influence of changes in trunk and pelvic posture during single leg standing on hip and thigh muscle activation in a pain free population.

PubMed

Prior, Simon; Mitchell, Tim; Whiteley, Rod; O'Sullivan, Peter; Williams, Benjamin K; Racinais, Sebastien; Farooq, Abdulaziz

2014-03-27

Thigh muscle injuries commonly occur during single leg loading tasks and patterns of muscle activation are thought to contribute to these injuries. The influence trunk and pelvis posture has on hip and thigh muscle activation during single leg stance is unknown and was investigated in a pain free population to determine if changes in body posture result in consistent patterns of changes in muscle activation. Hip and thigh muscle activation patterns were compared in 22 asymptomatic, male subjects (20-45 years old) in paired functionally relevant single leg standing test postures: Anterior vs. Posterior Trunk Sway; Anterior vs. Posterior Pelvic Rotation; Left vs. Right Trunk Shift; and Pelvic Drop vs. Raise. Surface EMG was collected from eight hip and thigh muscles calculating Root Mean Square. EMG was normalized to an "upright standing" reference posture. Repeated measures ANOVA was performed along with associated F tests to determine if there were significant differences in muscle activation between paired test postures. In right leg stance, Anterior Trunk Sway (compared to Posterior Sway) increased activity in posterior sagittal plane muscles, with a concurrent deactivation of anterior sagittal plane muscles (p: 0.016 - <0.001). Lateral hip abductor muscles increased activation during Left Trunk Shift (compared to Right) (p :≤ 0.001). Lateral Pelvic Drop (compared to Raise) decreased activity in hip abductors and increased hamstring, adductor longus and vastus lateralis activity (p: 0.037 - <0.001). Changes in both trunk and pelvic posture during single leg stance generally resulted in large, predictable changes in hip and thigh muscle activation in asymptomatic young males. Changes in trunk position in the sagittal plane and pelvis position in the frontal plane had the greatest effect on muscle activation. Investigation of these activation patterns in clinical populations such as hip and thigh muscle injuries may provide important insights into injury

Magnetic Resonance Assessment of Hypertrophic and Pseudo-Hypertrophic Changes in Lower Leg Muscles of Boys with Duchenne Muscular Dystrophy and Their Relationship to Functional Measurements

PubMed Central

Vohra, Ravneet S.; Lott, Donovan; Mathur, Sunita; Senesac, Claudia; Deol, Jasjit; Germain, Sean; Bendixen, Roxanna; Forbes, Sean C.; Sweeney, H. Lee; Walter, Glenn A.; Vandenborne, Krista

2015-01-01

Introduction The primary objectives of this study were to evaluate contractile and non-contractile content of lower leg muscles of boys with Duchenne muscular dystrophy (DMD) and determine the relationships between non-contractile content and functional abilities. Methods Lower leg muscles of thirty-two boys with DMD and sixteen age matched unaffected controls were imaged. Non-contractile content, contractile cross sectional area and non-contractile cross sectional area of lower leg muscles (tibialis anterior, extensor digitorum longus, peroneal, medial gastrocnemius and soleus) were assessed by magnetic resonance imaging (MRI). Muscle strength, timed functional tests and the Brooke lower extremity score were also assessed. Results Non-contractile content of lower leg muscles (peroneal, medial gastrocnemius, and soleus) was significantly greater than control group (p<0.05). Non-contractile content of lower leg muscles correlated with Brooke score (rs = 0.64-0.84) and 30 feet walk (rs = 0.66-0.80). Dorsiflexor (DF) and plantarflexor (PF) specific torque was significantly different between the groups. Discussion Overall, non-contractile content of the lower leg muscles was greater in DMD than controls. Furthermore, there was an age dependent increase in contractile content in the medial gastrocnemius of boys with DMD. The findings of this study suggest that T1 weighted MR images can be used to monitor disease progression and provide a quantitative estimate of contractile and non-contractile content of tissue in children with DMD. PMID:26103164

Muscle ultrasound quantifies disease progression over time in infants and young boys with duchenne muscular dystrophy.

PubMed

Zaidman, Craig M; Malkus, Elizabeth C; Connolly, Anne M

2015-09-01

Quantitative muscle ultrasound (QUS) in boys with Duchenne muscular dystrophy (DMD) shows increased echointensity as muscle is replaced with fat and fibrosis. Studies of quantitative ultrasound in infants/young boys with DMD over time have not been reported. We used calibrated muscle backscatter (cMB), a reproducible measure of ultrasound echointensity, to quantify muscle pathology in 5 young boys with DMD (ages 0.5-2.8 years) over 17-29 months. We compared the results with repeated assessments of function (n = 4) and with muscle ultrasound images from a cross-section of 6 male controls (0.6-3.1 years). cMB in boys with DMD increased (worsened) over time (P < 0.001), whereas function improved. After age 2 years, cMB in most (4 of 5) boys with DMD was higher than in any control. QUS measures disease progression in young boys with DMD despite functional improvements. QUS could be employed as an outcome measure for serial assessment of young boys with DMD. © 2015 Wiley Periodicals, Inc.

Leg muscle volume during 30-day 6-degree head-down bed rest with isotonic and isokinetic exercise training

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Lee, P. L.; Ellis, S.; Selzer, R. H.; Ortendahl, D. A.

1994-01-01

Magnetic resonance imaging (MRI) was used to compare the effect of two modes of lower-extremity exercise training on the mass (volume) of posterior leg group (PLG) muscles (soleus, flexor hallucis longus, tibialis posterior, lateral and medial gastrocnemius, and flexor digitorum longus) on 19 men (ages 32-42 years) subjected to intense dynamic-isotonic (ITE, cycle ergometer, number of subjects (N) = 7), isokinetic (IKE, torque egrometer, N = 7), and no exercise (NOE, N = 5) training for 60 min/day during head-down bed rest (HDBR). Total volume of the PLG muscles decreased (p less than 0.05) similarly: ITE = 4.3 +/- SE 1.6%, IKE = 7.7 +/- 1.6%, and NOE = 6.3 +/- 0.8%; combined volume (N = 19) loss was 6.1 +/- 0.9%. Ranges of volume changes were 2.6% to -9.0% (ITE), -2.1% to -14.9% (IKE), and -3.4% to -8/1% (NOE). Correlation coefficients (r) of muscle volume versus thickness measured with ultrasonography were: ITE r + 0.79 (p less than 0.05), IKE r = 0.27 (not significant (NS)), and NOE r = 0.63 (NS). Leg-muscle volume and thickness were highly correlated (r = 0.79) when plasma volume was maintained during HDBR with ITE. Thus, neither intensive lower extremity ITE nor IKE training influence the normal non-exercised posterior leg muscle atrophy during HDBR. The relationship of muscle volume and thickness may depend on the mode of exercise training associated with the maintenance of plasma volume.

[Electromyographic determination of the fatigability of respiratory and leg muscles before and after aortocoronary bypass operation].

PubMed

Worth, H; Grundmann, C; Goeckenjan, G; Smidt, U; Irlich, G; Loogen, F

1984-01-01

To study the effect of postoperative confinement to bed on respiratory muscle fatigue, 31 male subjects (age, 34-66 years) undergoing coronary artery revascularization were examined. Fatigue of both respiratory muscles (musculi intercostales externi) and leg muscles (musculus gastrocnemius) was determined by electromyography prior to and 7 and 12 days after operation. Additionally, oscillatory resistance to breathing and phase angle were measured. Pre- and postoperative routine lung function tests were performed. A comparison between preoperative and postoperative measurements reveals that respiratory as well as leg muscle fatigue occurred at higher loads during the preoperative and the second postoperative than during the first postoperative determination. After surgery vital capacity, total lung capacity, 1-second capacity, and, to a lower extent, thoracic gas volume were diminished, while specific airway conductance, oscillatory resistance to breathing, phase angle, residual volume, and relative 1-second capacity remained unchanged. The constancy of the latter parameters indicates that neither airway obstruction nor a significant restriction of the lung and/or thorax occurred due to surgery. Therefore, the increase of respiratory muscle fatigue after surgery may more probably be attributed to a lack of training of respiratory muscles which may contribute to limitation of ventilation in bedridden patients.

The reliability and validity of ultrasound to quantify muscles in older adults: a systematic review

PubMed Central

Scafoglieri, Aldo; Jager‐Wittenaar, Harriët; Hobbelen, Johannes S.M.; van der Schans, Cees P.

2017-01-01

Abstract This review evaluates the reliability and validity of ultrasound to quantify muscles in older adults. The databases PubMed, Cochrane, and Cumulative Index to Nursing and Allied Health Literature were systematically searched for studies. In 17 studies, the reliability (n = 13) and validity (n = 8) of ultrasound to quantify muscles in community‐dwelling older adults (≥60 years) or a clinical population were evaluated. Four out of 13 reliability studies investigated both intra‐rater and inter‐rater reliability. Intraclass correlation coefficient (ICC) scores for reliability ranged from −0.26 to 1.00. The highest ICC scores were found for the vastus lateralis, rectus femoris, upper arm anterior, and the trunk (ICC = 0.72 to 1.000). All included validity studies found ICC scores ranging from 0.92 to 0.999. Two studies describing the validity of ultrasound to predict lean body mass showed good validity as compared with dual‐energy X‐ray absorptiometry (r 2 = 0.92 to 0.96). This systematic review shows that ultrasound is a reliable and valid tool for the assessment of muscle size in older adults. More high‐quality research is required to confirm these findings in both clinical and healthy populations. Furthermore, ultrasound assessment of small muscles needs further evaluation. Ultrasound to predict lean body mass is feasible; however, future research is required to validate prediction equations in older adults with varying function and health. PMID:28703496

Investigating the Effects of Motion Streaks on pQCT-Derived Leg Muscle Density and Its Association With Fractures.

PubMed

Chan, Adrian C H; Adachi, Jonathan D; Papaioannou, Alexandra; Wong, Andy Kin On

Lower peripheral quantitative computed tomography (pQCT)-derived leg muscle density has been associated with fragility fractures in postmenopausal women. Limb movement during image acquisition may result in motion streaks in muscle that could dilute this relationship. This cross-sectional study examined a subset of women from the Canadian Multicentre Osteoporosis Study. pQCT leg scans were qualitatively graded (1-5) for motion severity. Muscle and motion streak were segmented using semi-automated (watershed) and fully automated (threshold-based) methods, computing area, and density. Binary logistic regression evaluated odds ratios (ORs) for fragility or all-cause fractures related to each of these measures with covariate adjustment. Among the 223 women examined (mean age: 72.7 ± 7.1 years, body mass index: 26.30 ± 4.97 kg/m 2 ), muscle density was significantly lower after removing motion (p < 0.001) for both methods. Motion streak areas segmented using the semi-automated method correlated better with visual motion grades (rho = 0.90, p < 0.01) compared to the fully automated method (rho = 0.65, p < 0.01). Although the analysis-reanalysis precision of motion streak area segmentation using the semi-automated method is above 5% error (6.44%), motion-corrected muscle density measures remained well within 2% analytical error. The effect of motion-correction on strengthening the association between muscle density and fragility fractures was significant when motion grade was ≥3 (p interaction <0.05). This observation was most dramatic for the semi-automated algorithm (OR: 1.62 [0.82,3.17] before to 2.19 [1.05,4.59] after correction). Although muscle density showed an overall association with all-cause fractures (OR: 1.49 [1.05,2.12]), the effect of motion-correction was again, most impactful within individuals with scans showing grade 3 or above motion. Correcting for motion in pQCT leg scans strengthened the relationship between

Development of a new Sonovue™ contrast-enhanced ultrasound approach reveals temporal and age-related features of muscle microvascular responses to feeding

PubMed Central

Mitchell, William Kyle; Phillips, Bethan E; Williams, John P; Rankin, Debbie; Smith, Kenneth; Lund, Jonathan N; Atherton, Philip J

2013-01-01

Compromised limb blood flow in aging may contribute to the development of sarcopenia, frailty, and the metabolic syndrome. We developed a novel contrast-enhanced ultrasound technique using Sonovue™ to characterize muscle microvasculature responses to an oral feeding stimulus (15 g essential amino acids) in young (∼20 years) and older (∼70 years) men. Intensity-time replenishment curves were made via an ultrasound probe “fixed” over the quadriceps, with intermittent high mechanical index destruction of microbubbles within muscle vasculature. This permitted real-time measures of microvascular blood volume (MBV), microvascular flow velocity (MFV) and their product, microvascular blood flow (MBF). Leg blood flow (LBF) was measured by Doppler and insulin by enzyme-linked immunosorbent assay. Steady-state contrast concentrations needed for comparison between different physiological states were achieved <150 sec from commencing Sonovue™ infusion, and MFV and MBV measurements were completed <120 sec thereafter. Interindividual coefficients of variation in MBV and MFV were 35–40%, (N = 36). Younger men (N = 6) exhibited biphasic vascular responses to feeding with early increases in MBV (+36%, P < 0.008 45 min post feed) reflecting capillary recruitment, and late increases in MFV (+77%, P < 0.008) and MBF (+130%, P < 0.007 195 min post feed) reflecting more proximal vessel dilatation. Early MBV responses were synchronized with peak insulin but not increased LBF, while later changes in MFV and MBF occurred with insulin at post absorptive values but alongside increased LBF. All circulatory responses were absent in old men (N = 7). Thus, impaired postprandial circulation could impact age-related declines in muscle glucose disposal, protein anabolism, and muscle mass. PMID:24303186

Monitoring Progression of Amyotrophic Lateral Sclerosis Using Ultrasound Morpho-Textural Muscle Biomarkers: A Pilot Study.

PubMed

Martínez-Payá, Jacinto J; Ríos-Díaz, José; Medina-Mirapeix, Francesc; Vázquez-Costa, Juan F; Del Baño-Aledo, María Elena

2018-01-01

The need is increasing for progression biomarkers that allow the loss of motor neurons in amyotrophic lateral sclerosis (ALS) to be monitored in clinical trials. In this prospective longitudinal study, muscle thickness, echointensity, echovariation and gray level co-occurrence matrix textural features are examined as possible progression ultrasound biomarkers in ALS patients during a 5-mo follow-up period. We subjected 13 patients to 3 measurements for 20 wk. They showed a significant loss of muscle, an evident tendency to loss of thickness and increased echointensity and echovariation. In regard to textural parameters, muscle heterogeneity tended to increase as a result of the neoformation of non-contractile tissue through denervation. Considering some limitations of the study, the quantitative muscle ultrasound biomarkers evaluated showed a promising ability to monitor patients affected by ALS. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

Local nitric oxide synthase inhibition reduces skeletal muscle glucose uptake but not capillary blood flow during in situ muscle contraction in rats.

PubMed

Ross, Renee M; Wadley, Glenn D; Clark, Michael G; Rattigan, Stephen; McConell, Glenn K

2007-12-01

We have previously shown in humans that local infusion of a nitric oxide synthase (NOS) inhibitor into the femoral artery attenuates the increase in leg glucose uptake during exercise without influencing total leg blood flow. However, rodent studies examining the effect of NOS inhibition on contraction-stimulated skeletal muscle glucose uptake have yielded contradictory results. This study examined the effect of local infusion of an NOS inhibitor on skeletal muscle glucose uptake (2-deoxyglucose) and capillary blood flow (contrast-enhanced ultrasound) during in situ contractions in rats. Male hooded Wistar rats were anesthetized and one hindleg electrically stimulated to contract (2 Hz, 0.1 ms) for 30 min while the other leg rested. After 10 min, the NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) (arterial concentration of 5 micromol/l) or saline was infused into the epigastric artery of the contracting leg. Local NOS inhibition had no effect on blood pressure, heart rate, or muscle contraction force. Contractions increased (P < 0.05) skeletal muscle NOS activity, and this was prevented by L-NAME infusion. NOS inhibition caused a modest significant (P < 0.05) attenuation of the increase in femoral blood flow during contractions, but importantly there was no effect on capillary recruitment. NOS inhibition attenuated (P < 0.05) the increase in contraction-stimulated skeletal muscle glucose uptake by approximately 35%, without affecting AMP-activated protein kinase (AMPK) activation. NOS inhibition attenuated increases in skeletal muscle glucose uptake during contraction without influencing capillary recruitment, suggesting that NO is critical for part of the normal increase in skeletal muscle fiber glucose uptake during contraction.

Dissociation of muscle sympathetic nerve activity and leg vascular resistance in humans

NASA Technical Reports Server (NTRS)

Shoemaker, J. K.; Herr, M. D.; Sinoway, L. I.

2000-01-01

We examined the hypothesis that the increase in inactive leg vascular resistance during forearm metaboreflex activation is dissociated from muscle sympathetic nerve activity (MSNA). MSNA (microneurography), femoral artery mean blood velocity (FAMBV, Doppler), mean arterial pressure (MAP), and heart rate (HR) were assessed during fatiguing static handgrip exercise (SHG, 2 min) followed by posthandgrip ischemia (PHI, 2 min). Whereas both MAP and MSNA increase during SHG, the transition from SHG to PHI is characterized by a transient reduction in MAP but sustained elevation in MSNA, facilitating separation of these factors in vivo. Femoral artery vascular resistance (FAVR) was calculated (MAP/MBV). MSNA increased by 59 +/- 20% above baseline during SHG (P < 0.05) and was 58 +/- 18 and 78 +/- 18% above baseline at 10 and 20 s of PHI, respectively (P < 0.05 vs. baseline). Compared with baseline, FAVR increased 51 +/- 22% during SHG (P < 0.0001) but returned to baseline levels during the first 30 s of PHI, reflecting the changes in MAP (P < 0.005) and not MSNA. It was concluded that control of leg muscle vascular resistance is sensitive to changes in arterial pressure and can be dissociated from sympathetic factors.

Different fatigue-resistant leg muscles and EMG response during whole-body vibration.

PubMed

Simsek, Deniz

2017-12-01

The purpose of this study was to determine the effects of static whole-body vibration (WBV) on the Electromyograhic (EMG) responses of leg muscles, which are fatigue-resistant in different manner. The study population was divided into two groups according to the values obtained by the Fatigue Index [Group I: Less Fatigue Resistant (LFR), n=11; Group II: More Fatigue Resistant (MFR), n=11]. The repeated electromyographic (EMG) activities of four leg muscles were analyzed the following determinants: (1) frequency (30 Hz, 35 Hz and 40 Hz); (2) stance position (static squat position); (3) amplitude (2 mm and 4 mm) and (4) knee flexion angle (120°), (5) vertical vibration platform. Vibration data were analyzed using Minitab 16 (Minitab Ltd, State College, PA, USA). The significance level was set at p<.05. The study results showed that static WBV stimuli given at different frequencies and amplitudes resulted in a significant increase (p<.05) in compared, the LFR group showed significantly (1) higher rates of quadriceps femoris and hamstring muscle fatigue (p<.05), (2) higher levels of knee extensor and flexor torque (p<.05) and (3) higher percentage increases in EMG activation at higher frequencies (max at 40 Hz) and amplitudes (4 mm) (p<.05). The present study can be used for the optimal prescription of vibration exercise and can serve to guide the development of training programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pharmacological vasodilation improves insulin-stimulated muscle protein anabolism but not glucose utilization in older adults.

PubMed

Timmerman, Kyle L; Lee, Jessica L; Fujita, Satoshi; Dhanani, Shaheen; Dreyer, Hans C; Fry, Christopher S; Drummond, Micah J; Sheffield-Moore, Melinda; Rasmussen, Blake B; Volpi, Elena

2010-11-01

Skeletal muscle protein metabolism is resistant to the anabolic action of insulin in healthy, nondiabetic older adults. This defect is associated with impaired insulin-induced vasodilation and mTORC1 signaling. We hypothesized that, in older subjects, pharmacological restoration of insulin-induced capillary recruitment would improve the response of muscle protein synthesis and anabolism to insulin. Twelve healthy, nondiabetic older subjects (71 ± 2 years) were randomized to two groups. Subjects were studied at baseline and during local infusion in one leg of insulin alone (Control) or insulin plus sodium nitroprusside (SNP) at variable rate to double leg blood flow. We measured leg blood flow by dye dilution; muscle microvascular perfusion with contrast enhanced ultrasound; Akt/mTORC1 signaling by Western blotting; and muscle protein synthesis, amino acid, and glucose kinetics using stable isotope methodologies. There were no baseline differences between groups. Blood flow, muscle perfusion, phenylalanine delivery to the leg, and intracellular availability of phenylalanine increased significantly (P < 0.05) in SNP only. Akt phosphorylation increased in both groups but increased more in SNP (P < 0.05). Muscle protein synthesis and net balance (nmol · min(-1) · 100 ml · leg(-1)) increased significantly (P < 0.05) in SNP (synthesis, 43 ± 6 to 129 ± 25; net balance, -16 ± 3 to 26 ± 12) but not in Control (synthesis, 41 ± 10 to 53 ± 8; net balance, -17 ± 3 to -2 ± 3). Pharmacological enhancement of muscle perfusion and amino acid availability during hyperinsulinemia improves the muscle protein anabolic effect of insulin in older adults.

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

Muscle activity during leg strengthening exercise using free weights and elastic resistance: effects of ballistic vs controlled contractions.

PubMed

Jakobsen, Markus Due; Sundstrup, Emil; Andersen, Christoffer H; Aagaard, Per; Andersen, Lars L

2013-02-01

The present study's aim was to evaluate muscle activity during leg exercises using elastic vs. isoinertial resistance at different exertion and loading levels, respectively. Twenty-four women and eighteen men aged 26-67 years volunteered to participate in the experiment. Electromyographic (EMG) activity was recorded in nine muscles during a standardized forward lunge movement performed with dumbbells and elastic bands during (1) ballistic vs. controlled exertion, and (2) at low, medium and high loads (33%, 66% and 100% of 10 RM, respectively). The recorded EMG signals were normalized to MVC EMG. Knee joint angle was measured using electronic inclinometers. The following results were obtained. Loading intensity affected EMG amplitude in the order: lowmuscles ballistic contractions with medium load showed similar EMG amplitude as controlled contractions with high load. At flexed knee joint positions with elastic resistance, quadriceps and gluteus EMG amplitude during medium-load ballistic contractions exceeded that recorded during high-load controlled contractions. Quadriceps and gluteus EMG amplitude increased at flexed knee positions. In contrast, hamstrings EMG amplitude remained constant throughout ROM during dumbbell lunge, but increased at more extended knee joint positions during lunges using elastic resistance. Based on these results, it can be concluded that lunges performed using medium-load ballistic muscle contractions may induce similar or even higher leg muscle activity than lunges using high-load slow-speed contractions. Consequently, lunges using elastic resistance appear to be equally effective in inducing high leg muscle activity as traditional lunges using isoinertial resistance. Copyright © 2012 Elsevier B.V. All rights reserved.

Neuromuscular ultrasound imaging in low back pain patients with radiculopathy.

PubMed

Frost, Lydia R; Brown, Stephen H M

2016-02-01

Patients suffering from chronic low back pain with associated radiculopathy (LBP-R), or sciatica, experience neuromuscular symptoms in the lower back and leg; however, research to date has focussed solely on the lower back. To expand neuromuscular research of LBP-R patients into the lower limb, using ultrasound imaging. Case control study comparing LBP-R patients to matched healthy controls. LBP-R patients with disc bulge or herniation (L3/L4 to L5/S1) resulting in unilateral radiculopathy (n = 17) and healthy matched controls (n = 17) were recruited. High-resolution ultrasound imaging was used to investigate sciatic nerve structure, as well as the quality (relative magnitude of fat/fibrosis infiltration) and contraction (muscle thickening) of associated musculature in the lower back (paraspinals) and lower limb (biceps femoris, gastrocnemius, soleus). LBP-R patients had swollen sciatic nerves (increased cross sectional area), but this was not associated with evidence of reduced lower limb muscle quality. As compared to controls, LBP-R patients demonstrated less soleus muscle thickening during submaximal contraction; however, there were no impairments in the hamstring or lower back musculature. Ultrasound imaging was an effective method to detect sciatic nerve swelling in mild to moderately affected LBP-R patients. Nerve swelling was not associated with poorer muscle quality, nor consistently impaired muscle contraction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Assessment of pelvic floor muscle contraction with palpation, perineometry and transperineal ultrasound: a cross-sectional study.

PubMed

Volløyhaug, I; Mørkved, S; Salvesen, Ø; Salvesen, K Å

2016-06-01

To study the correlation between palpation, perineometry and transperineal ultrasound for assessment of pelvic floor muscle contraction and to define a contraction scale for ultrasound measurements. This was a cross-sectional study of 608 women examined with palpation of pelvic floor muscle contraction, using the Modified Oxford Scale, and measurement of the vaginal squeeze pressure with a vaginal balloon connected to a fiber-optic microtip transducer (perineometry). Transperineal ultrasound was used for measurements of levator hiatal area and anteroposterior (AP) diameter in the plane of minimal hiatal dimensions, at rest and on contraction. The pelvic floor muscle contraction was expressed as the percentage difference between values at rest and on contraction. Spearman's rank was used to test for correlation between the different methods of assessment. Significant correlations were found between all assessment methods (P < 0.001). Palpation correlated with perineometry (rs = 0.74) and with proportional change in hiatal area (rs = 0.67) and AP diameter (rs = 0.69) on ultrasound. Perineometry correlated with proportional change in hiatal area (rs = 0.60) and AP diameter (rs = 0.66) on ultrasound. We defined a contraction scale based on the proportional change in AP diameter. In this population, a change in AP diameter of < 7% corresponded to absence of contractions, 7-18% corresponded to weak contractions, 18-35% corresponded to normal contractions and > 35% corresponded to strong contractions. We found moderate to strong correlation between ultrasound measurements, palpation and perineometry for assessing pelvic floor muscle contraction. The proportional change in levator hiatal AP diameter was the ultrasound measurement with strongest correlation to palpation and perineometry and formed the basis for the contraction scale for ultrasound measurements. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley

Function-sparing tibialis anterior pivoted muscle flap for reconstruction of post-burn and post-traumatic middle-third leg defects with exposed tibia

PubMed Central

Megahed, M.A.

2011-01-01

Summary Reconstruction of the middle third of the leg is a challenging procedure. The tibialis anterior muscle flap can be useful in reconstruction of the middle third of the leg with exposed tibia. The aim of this work was to evaluate the efficacy of tibialis anterior pivoted muscle flap for reconstruction of the middle third of the leg with functional preservation. This study, performed in the Plastic, Reconstructive and Burn Unit, Menoufiya University Hospital, Egypt, included 16 patients (13 males and 3 females) during the period February 2007/May 2010: seven post-burn and nine post-traumatic patients with post-burn middle-third leg defects with exposed tibia. Their ages ranged from 14 to 67 years. A function-sparing lateral split tibialis anterior pivoted muscle flap was used in all the patients. Follow-up ranged from six months to two years. Partial flap loss occurred in one patient (6.25%), there was no post-operative haematoma or infection, and only one case of wound dehiscence (6.25%), managed by secondary suture. No donor site morbidity or any significant functional impairment was observed, and the subjective aesthetic results were satisfactory. Lateral split tibialis anterior pivoted muscle flap is a useful, simple technique, allowing rapid, durable and reliable coverage of middle-third leg defects without significant impairment of function and without sacrificing major nerves or vessels in the foot, and without any donor site morbidity. PMID:22262962

Quantification of muscle oxygenation and flow of healthy volunteers during cuff occlusion of arm and leg flexor muscles and plantar flexion exercise

NASA Astrophysics Data System (ADS)

Durduran, Turgut; Yu, Guoqiang; Zhou, Chao; Lech, Gwen; Chance, Britton; Yodh, Arjun G.

2003-07-01

A hybrid instrument combining near infrared and diffuse correlation spectroscopies was used to measure muscle oxygenation and blood flow dynamics during cuff occlusion and ischemia. Measurements were done on six healthy subjects on their arm and leg flexor muscles. Hemodynamic response was characterized for blood oxygen saturation, total hemoglobin concenration and relative blood flow speed. The characterization allowed us to define the normal response range as well as showing the feasibility of using a hybrid instrument for dynamic measurements.

Night Leg Cramps

MedlinePlus

... feet or thighs might cramp as well. Forcefully stretching the contracted muscle relieves the pain. Most of ... include Drinking plenty of fluids to avoid dehydration Stretching your leg muscles or riding a stationary bicycle ...

Mean individual muscle activities and ratios of total muscle activities in a selective muscle strengthening experiment: the effects of lower limb muscle activity based on mediolateral slope angles during a one-leg stance.

PubMed

Lee, Sang-Yeol

2016-09-01

[Purpose] The purpose of this study was to provide basic data for research on selective muscle strengthening by identifying mean muscle activities and calculating muscle ratios for use in developing strengthening methods. [Subjects and Methods] Twenty-one healthy volunteers were included in this study. Muscle activity was measured during a one-leg stance under 6 conditions of slope angle: 0°, 5°, 10°, 15°, 20°, and 25°. The data used in the analysis were root mean square and % total muscle activity values. [Results] There were significant differences in the root mean square of the gluteus medius, the hamstring, and the medial gastrocnemius muscles. There were significant differences in % total muscle activity of the medial gastrocnemius. [Conclusion] Future studies aimed at developing selective muscle strengthening methods are likely to yield more effective results by using muscle activity ratios based on electromyography data.

Leg kinematics and muscle activity during treadmill running in the cockroach, Blaberus discoidalis: I. Slow running.

PubMed

Watson, J T; Ritzmann, R E

1998-01-01

We have combined high-speed video motion analysis of leg movements with electromyogram (EMG) recordings from leg muscles in cockroaches running on a treadmill. The mesothoracic (T2) and metathoracic (T3) legs have different kinematics. While in each leg the coxa-femur (CF) joint moves in unison with the femurtibia (FT) joint, the relative joint excursions differ between T2 and T3 legs. In T3 legs, the two joints move through approximately the same excursion. In T2 legs, the FT joint moves through a narrower range of angles than the CF joint. In spite of these differences in motion, no differences between the T2 and T3 legs were seen in timing or qualitative patterns of depressor coxa and extensor tibia activity. The average firing frequencies of slow depressor coxa (Ds) and slow extensor tibia (SETi) motor neurons are directly proportional to the average angular velocity of their joints during stance. The average Ds and SETi firing frequency appears to be modulated on a cycle-by-cycle basis to control running speed and orientation. In contrast, while the frequency variations within Ds and SETi bursts were consistent across cycles, the variations within each burst did not parallel variations in the velocity of the relevant joints.

Female PFP patients present alterations in eccentric muscle activity but not the temporal order of activation of the vastus lateralis muscle during the single leg triple hop test.

PubMed

Kalytczak, Marcelo Martins; Lucareli, Paulo Roberto Garcia; Dos Reis, Amir Curcio; Bley, André Serra; Biasotto-Gonzalez, Daniela Aparecida; Correa, João Carlos Ferrari; Politti, Fabiano

2018-04-07

This study aimed to compare the concentric and eccentric activity and the temporal order of peak activity of the hip and knee muscles between women with patellofemoral pain (PFP) and healthy women during the single leg triple hop test (SLTHT). Electromyographic (EMG) and Kinematic data were collected from 14 healthy women (CG) and 14 women diagnosed with PFP (PFG) during a single session of the single leg triple hop test. Integral surface electromyography (iEMG) data of the hip and knee muscles in eccentric and concentric phases and the length of time that each muscle needed to reach the maximal peak of muscle activity were calculated. The iEMG in the eccentric phase was significantly higher (p < 0.05) than the concentric phase, for the gluteus maximus and gluteus medius muscles (CG and PFG) and for the vastus lateralis muscle (PFG). The vastus lateralis muscle was the first muscle to reach the highest peak of activity in the PFG, and the third to reach this peak in the CG. In the present study, the activity of the vastus lateralis muscle during the eccentric phase of the jump was greater than concentric phase, as a temporal anticipation of its peak in activity among women with PFP. Copyright © 2018 Elsevier B.V. All rights reserved.

The comparison of manual lymph drainage and ultrasound therapy on the leg swelling caused by wearing high heels.

PubMed

Lee, Dong-Yeop; Han, Ji-Su; Jang, Eun-Ji; Seo, Dong-Kwon; Hong, Ji-Heon; Lee, Sang-Sook; Lee, Dong-Geol; Yu Lee, Jae-Ho

2014-01-01

One of the major symptoms when women are wearing high heels for a long time is leg swelling. The purpose of this study was to compare the effect of manual lymph drainage with ultrasound therapy. The forty-five healthy women of twenties were participated in this study and divided randomly into three groups; manual lymph drainage group (n=15), ultrasound therapy group (n=15) and control group (n=15). Swelling was measured before wearing the high heels (10 cm-height), after one-hour of wearing the high heels, wearing the high heels of one-hour after the intervention of 15 minutes. Also swelling was calculated by using a tape measure, volumeter and body composition analyzer. Statistical analysis of the comparison between the three groups was performed by one-way ANOVA. Also comparison to the mean value in swelling according to the time was performed by repeated measure ANOVA. As the result of this study, a significant changes have emerged within each of manual lymph drainage, ultrasound therapy and control group (p< 0.05). However, there were no significant differences between each group (p> 0.05). But the mean value of manual lymph drainage group showed the tendency of fast recovering before causing swelling. Therefore, we consider that the clinical treatment of manual lymph drainage and ongoing studies will be made since manual lymph drainage is very effective in releasing the leg swelling caused by wearing high heels and standing for a long time at work.

Molecular plasticity and functional enhancements of leg muscles in response to hypergravity in the fruit fly Drosophila melanogaster.

PubMed

Schilder, Rudolf J; Raynor, Megan

2017-10-01

Studies of organismal and tissue biomechanics have clearly demonstrated that musculoskeletal design is strongly dependent on experienced loads, which can vary in the short term, as a result of growth during life history and during the evolution of animal body size. However, how animals actually perceive and make adjustments to their load-bearing musculoskeletal elements that accommodate variation in their body weight is poorly understood. We developed an experimental model system that can be used to start addressing these open questions, and uses hypergravity centrifugation to experimentally manipulate the loads experienced by Drosophila melanogaster We examined effects of this manipulation on leg muscle alternative splicing of the sarcomere gene troponin T ( Dmel\\up ; Fbgn0004169, herein referred to by its synonym TnT ), a process that was previously demonstrated to precisely correlate with quantitative variation in body weight in Lepidoptera and rat. In a similar fashion, hypergravity centrifugation caused fast (i.e. within 24 h) changes to fly leg muscle TnT alternative splicing that correlated with body weight variation across eight D. melanogaster lines. Hypergravity treatment also appeared to enhance leg muscle function, as centrifuged flies showed an increased negative geotaxis response and jump ability. Although the identity and location of the sensors and effectors involved remains unknown, our results provide further support for the existence of an evolutionarily conserved mechanism that translates signals that encode body weight into appropriate skeletal muscle molecular and functional responses. © 2017. Published by The Company of Biologists Ltd.

Subglottal pressure, tracheal airflow, and intrinsic laryngeal muscle activity during rat ultrasound vocalization

PubMed Central

2011-01-01

Vocal production requires complex planning and coordination of respiratory, laryngeal, and vocal tract movements, which are incompletely understood in most mammals. Rats produce a variety of whistles in the ultrasonic range that are of communicative relevance and of importance as a model system, but the sources of acoustic variability were mostly unknown. The goal was to identify sources of fundamental frequency variability. Subglottal pressure, tracheal airflow, and electromyographic (EMG) data from two intrinsic laryngeal muscles were measured during 22-kHz and 50-kHz call production in awake, spontaneously behaving adult male rats. During ultrasound vocalization, subglottal pressure ranged between 0.8 and 1.9 kPa. Pressure differences between call types were not significant. The relation between fundamental frequency and subglottal pressure within call types was inconsistent. Experimental manipulations of subglottal pressure had only small effects on fundamental frequency. Tracheal airflow patterns were also inconsistently associated with frequency. Pressure and flow seem to play a small role in regulation of fundamental frequency. Muscle activity, however, is precisely regulated and very sensitive to alterations, presumably because of effects on resonance properties in the vocal tract. EMG activity of cricothyroid and thyroarytenoid muscle was tonic in calls with slow or no fundamental frequency modulations, like 22-kHz and flat 50-kHz calls. Both muscles showed brief high-amplitude, alternating bursts at rates up to 150 Hz during production of frequency-modulated 50-kHz calls. A differentiated and fine regulation of intrinsic laryngeal muscles is critical for normal ultrasound vocalization. Many features of the laryngeal muscle activation pattern during ultrasound vocalization in rats are shared with other mammals. PMID:21832032

Effects of age and muscle action type on acute strength and power recovery following fatigue of the leg flexors.

PubMed

Thompson, Brennan J; Conchola, Eric C; Stock, Matt S

2015-12-01

Short-term strength and power recovery patterns following fatigue have received little research attention, particularly as they pertain to age-specific responses, and the leg flexors (i.e., hamstrings) muscle group. Thus, research is warranted addressing these issues because both age-related alterations in the neuromuscular system and mode of muscle action (e.g., eccentric, concentric, isometric) may differentially influence recovery responses from fatigue. The aim of this study was to investigate the strength and power recovery responses for eccentric, concentric, and isometric muscle actions of the leg flexors in young and older men following an isometric, intermittent fatigue-inducing protocol. Nineteen young (age = 25 ± 3 years) and nineteen older (71 ± 4) men performed maximal voluntary contractions (MVCs) for eccentric, concentric, and isometric muscle actions followed by a fatigue protocol of intermittent (0.6 duty cycle) isometric contractions of the leg flexors at 60% of isometric MVC. MVCs of each muscle action were performed at 0, 7, 15, and 30 min following fatigue. Peak torque (PT) and mean power values were calculated from the MVCs and the eccentric/concentric ratio (ECR) was derived. For PT and mean power, young men showed incomplete recovery at all time phases, whereas the older men had recovered by 7 min. Eccentric and isometric muscle actions showed incomplete recovery at all time phases, but concentric recovered by 7 min, independent of age. The ECR was depressed for up to 30 min following fatigue. More rapid and pronounced recovery in older men and concentric contractions may be related to physiological differences specific to aging and muscle action motor unit patterns. Individuals and clinicians may use these time course responses as a guide for recovery following activity-induced fatigue.

Automatic measurement of pennation angle and fascicle length of gastrocnemius muscles using real-time ultrasound imaging.

PubMed

Zhou, Guang-Quan; Chan, Phoebe; Zheng, Yong-Ping

2015-03-01

Muscle imaging is a promising field of research to understand the biological and bioelectrical characteristics of muscles through the observation of muscle architectural change. Sonomyography (SMG) is a technique which can quantify the real-time architectural change of muscles under different contractions and motions with ultrasound imaging. The pennation angle and fascicle length are two crucial SMG parameters to understand the contraction mechanics at muscle level, but they have to be manually detected on ultrasound images frame by frame. In this study, we proposed an automatic method to quantitatively identify pennation angle and fascicle length of gastrocnemius (GM) muscle based on multi-resolution analysis and line feature extraction, which could overcome the limitations of tedious and time-consuming manual measurement. The method started with convolving Gabor wavelet specially designed for enhancing the line-like structure detection in GM ultrasound image. The resulting image was then used to detect the fascicles and aponeuroses for calculating the pennation angle and fascicle length with the consideration of their distribution in ultrasound image. The performance of this method was tested on computer simulated images and experimental images in vivo obtained from normal subjects. Tests on synthetic images showed that the method could identify the fascicle orientation with an average error less than 0.1°. The result of in vivo experiment showed a good agreement between the results obtained by the automatic and the manual measurements (r=0.94±0.03; p<0.001, and r=0.95±0.02, p<0.001). Furthermore, a significant correlation between the ankle angle and pennation angle (r=0.89±0.05; p<0.001) and fascicle length (r=-0.90±0.04; p<0.001) was found for the ankle plantar flexion. This study demonstrated that the proposed method was able to automatically measure the pennation angle and fascicle length of GM ultrasound images, which made it feasible to investigate

Postural adjustments associated with voluntary contraction of leg muscles in standing man.

PubMed

Nardone, A; Schieppati, M

1988-01-01

The postural adjustments associated with a voluntary contraction of the postural muscles themselves have been studied in the legs of normal standing men. We focussed on the following questions. Do postural adjustments precede the focal movement as in the case of movements of the upper limb? Which muscle(s) are involved in the task of stabilizing posture? Can the same postural muscle be activated in postural stabilization and in voluntary movement at the same time, in spite of the opposite changes in activity possibly required by these conditions? Six subjects standing on a dynamometric platform were asked to rise onto the tips their toes by contracting their soleus muscles, or to rock on their heels by contracting their tibialis anterior muscles. The tasks were made in a reaction time (RT) situation or in a self-paced mode, standing either freely or holding onto a stable structure. Surface EMGs of leg and thigh muscles, and the foot-floor reaction forces were recorded. The following results were obtained in the RT mode, standing freely. 1. Rising onto toe tips: a striking silent period in soleus preceded its voluntary activation; during this silent period, a tibialis anterior burst could be observed in three subjects; these anticipatory activities induced a forward sway, as monitored by a change in the force exerted along the x axis of the platform. 2. Rocking on heels: an enhancement in tonic EMG of soleus was observed before tibialis anterior voluntary burst, at a mean latency from the go-signal similar to that of the silent period; this anticipatory activity induced a backward body sway. 3. Choice RT conditions showed that the above anticipatory patterns in muscle activity were pre-programmed, specific for the intended tasks, and closely associated with the focal movement. When both tasks were performed in a self-paced mode, all the above EMG and mechanical features were more pronounced and unfolded in time. If the subjects held onto the frame, the early

A low arm and leg muscle mass to total body weight ratio is associated with an increased prevalence of metabolic syndrome: The Korea National Health and Nutrition Examination Survey 2010-2011.

PubMed

Kim, Yong Hwan; So, Wi-Young

2016-09-14

The aim of this study was to investigate the association between metabolic syndrome (MetS) and arm and leg muscle mass to total weight ratios in Korean adults. This was a randomized, controlled, cross-sectional study. Data from 2,383 adults (1,030 men and 1,353 women) were collected from the Korea National Health and Nutrition Examination Survey 2010-2011. Blood lipid profiles, blood pressure, and anthropometric characteristics, including weight, height, waist circumference, and muscle mass on dual energy X-ray absorptiometry (DXA), were evaluated in the participants. MetS was defined according to the criteria of the National Cholesterol Education Program Adult Treatment Panel III. The average mass of both arms and legs was determined using regional muscle analysis by DXA. Afterwards, the arm and leg muscle mass to total body weight ratio was determined and classified into 4 quartiles (i.e., quartile 1 [highest muscle ratio] to quartile 4 [lowest muscle ratio]). According to the arm muscle and leg muscle ratios, there was a higher prevalence of MetS in quartile 4 than in quartile 1 in both men and women. A low arm and leg muscle mass to body weight ratio was associated with a higher prevalence of MetS after adjusting for age, physical activity, frequency of smoking, and frequency of alcohol consumption. In conclusion, MetS patients demonstrated a lower arm and leg muscle mass to body weight ratio. Strength training for the lower and upper extremities is recommended because it can have a positive effect on MetS prevention.

Comparison Between Neck and Shoulder Stiffness Determined by Shear Wave Ultrasound Elastography and a Muscle Hardness Meter.

PubMed

Akagi, Ryota; Kusama, Saki

2015-08-01

The goals of this study were to compare neck and shoulder stiffness values determined by shear wave ultrasound elastography with those obtained with a muscle hardness meter and to verify the correspondence between objective and subjective stiffness in the neck and shoulder. Twenty-four young men and women participated in the study. Their neck and shoulder stiffness was determined at six sites. Before the start of the measurements, patients rated their present subjective symptoms of neck and shoulder stiffness on a 6-point verbal scale. At all measurement sites, the correlation coefficients between the values of muscle hardness indices determined by the muscle hardness meter and shear wave ultrasound elastography were not significant. Furthermore, individuals' subjective neck and shoulder stiffness did not correspond to their objective symptoms. These results suggest that the use of shear wave ultrasound elastography is essential to more precisely assess neck and shoulder stiffness. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Intramuscular pressures beneath elastic and inelastic leggings

NASA Technical Reports Server (NTRS)

Murthy, G.; Ballard, R. E.; Breit, G. A.; Watenpaugh, D. E.; Hargens, A. R.

1994-01-01

Leg compression devices have been used extensively by patients to combat chronic venous insufficiency and by astronauts to counteract orthostatic intolerance following spaceflight. However, the effects of elastic and inelastic leggings on the calf muscle pump have not been compared. The purpose of this study was to compare in normal subjects the effects of elastic and inelastic compression on leg intramuscular pressure (IMP), an objective index of calf muscle pump function. IMP in soleus and tibialis anterior muscles was measured with transducer-tipped catheters. Surface compression between each legging and the skin was recorded with an air bladder. Subjects were studied under three conditions: (1) control (no legging), (2) elastic legging, and (3) inelastic legging. Pressure data were recorded for each condition during recumbency, sitting, standing, walking, and running. Elastic leggings applied significantly greater surface compression during recumbency (20 +/- 1 mm Hg, mean +/- SE) than inelastic leggings (13 +/- 2 mm Hg). During recumbency, elastic leggings produced significantly higher soleus IMP of 25 +/- 1 mm Hg and tibialis anterior IMP of 28 +/- 1 mm Hg compared to 17 +/- 1 mm Hg and 20 +/- 2 mm Hg, respectively, generated by inelastic leggings and 8 +/- 1 mm Hg and 11 +/- 1 mm Hg, respectively, without leggings. During sitting, walking, and running, however, peak IMPs generated in the muscular compartments by elastic and inelastic leggings were similar. Our results suggest that elastic leg compression applied over a long period in the recumbent posture may impede microcirculation and jeopardize tissue viability.(ABSTRACT TRUNCATED AT 250 WORDS).

Age-related differences in the response of leg muscle cross-sectional area and water diffusivity measures to a period of supine rest.

PubMed

Lorbergs, Amanda L; Noseworthy, Michael D; MacIntyre, Norma J

2015-06-01

The object was to assess whether cross-sectional area (CSA) and water diffusion properties of leg muscles in young and older women change with increased time spent in supine rest. Healthy young (n = 9, aged 20-30 years) and older (n = 9, aged 65-75 years) women underwent MRI scanning of the right leg at baseline, 30 and 60 min of supine rest. Muscle CSA was derived from proton density images. Water diffusion properties [apparent diffusion coefficient (ADC) and fractional anisotropy (FA)] of the tibialis anterior and posterior, soleus, and medial and lateral heads of the gastrocnemius were derived from diffusion tensor imaging (DTI). Repeated measures ANOVAs and Bonferroni post hoc tests determined the effects of time and group on each muscle outcome. In both groups, muscle CSA and FA did not significantly change over time, whereas ADC significantly decreased. A greater decline at 30 min for young women was only observed for ADC in the medial gastrocnemius. Regardless of age, ADC values decreased with fluid shift associated with time spent supine, whereas CSA and FA were not affected. For leg muscle assessment in young and older women, DTI scanning protocols should consider the amount of time spent in a recumbent position.

The validity of anthropometric leg muscle volume estimation across a wide spectrum: From able-bodied adults to individuals with a spinal cord injury

PubMed Central

Venturelli, Massimo; Jeong, Eun-Kee; Richardson, Russell S.

2014-01-01

The assessment of muscle volume, and changes over time, have significant clinical and research-related implications. Methods to assess muscle volume vary from simple and inexpensive to complex and expensive. Therefore this study sought to examine the validity of muscle volume estimated simply by anthropometry compared with the more complex proton magnetic resonance imaging (1H-MRI) across a wide spectrum of individuals including those with a spinal cord injury (SCI), a group recognized to exhibit significant muscle atrophy. Accordingly, muscle volume of the thigh and lower leg of eight subjects with a SCI and eight able-bodied subjects (controls) was determined by anthropometry and 1H-MRI. With either method, muscle volumes were significantly lower in the SCI compared with the controls (P < 0.05) and, using pooled data from both groups, anthropometric measurements of muscle volume were strongly correlated to the values assessed by 1H-MRI in both the thigh (r2 = 0.89; P < 0.05) and lower leg (r2 = 0.98; P < 0.05). However, the anthropometric approach systematically overestimated muscle volume compared with 1H-MRI in both the thigh (mean bias = 2407cm3) and the lower (mean bias = 170 cm3) leg. Thus with an appropriate correction for this systemic overestimation, muscle volume estimated from anthropometric measurements is a valid approach and provides acceptable accuracy across a spectrum of adults with normal muscle mass to a SCI and severe muscle atrophy. In practical terms this study provides the formulas that add validity to the already simple and inexpensive anthropometric approach to assess muscle volume in clinical and research settings. PMID:24458749

Massage induces an immediate, albeit short-term, reduction in muscle stiffness.

PubMed

Eriksson Crommert, M; Lacourpaille, L; Heales, L J; Tucker, K; Hug, F

2015-10-01

Using ultrasound shear wave elastography, the aims of this study were: (a) to evaluate the effect of massage on stiffness of the medial gastrocnemius (MG) muscle and (b) to determine whether this effect (if any) persists over a short period of rest. A 7-min massage protocol was performed unilaterally on MG in 18 healthy volunteers. Measurements of muscle shear elastic modulus (stiffness) were performed bilaterally (control and massaged leg) in a moderately stretched position at three time points: before massage (baseline), directly after massage (follow-up 1), and following 3 min of rest (follow-up 2). Directly after massage, participants rated pain experienced during the massage. MG shear elastic modulus of the massaged leg decreased significantly at follow-up 1 (-5.2 ± 8.8%, P = 0.019, d = -0.66). There was no difference between follow-up 2 and baseline for the massaged leg (P = 0.83) indicating that muscle stiffness returned to baseline values. Shear elastic modulus was not different between time points in the control leg. There was no association between perceived pain during the massage and stiffness reduction (r = 0.035; P = 0.89). This is the first study to provide evidence that massage reduces muscle stiffness. However, this effect is short lived and returns to baseline values quickly after cessation of the massage. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Ankle muscle activity modulation during single-leg stance differs between children, young adults and seniors.

PubMed

Kurz, Eduard; Faude, Oliver; Roth, Ralf; Zahner, Lukas; Donath, Lars

2018-02-01

Incomplete maturation and aging-induced declines of the neuromuscular system affect postural control both in children and older adults and lead to high fall rates. Age-specific comparisons of the modulation of ankle muscle activation and behavioral center of pressure (COP) indices during upright stance have been rarely conducted. The objective of the present study was to quantify aging effects on a neuromuscular level. Thus, surface electromyography (SEMG) modulation and co-activity of ankle muscles during single-leg standing was compared in healthy children, young adults and seniors. Postural steadiness (velocity and mean sway frequency of COP), relative muscle activation (SEMG modulation) and co-activation of two ankle muscles (tibialis anterior, TA; soleus, SO) were examined during single-leg stance in 19 children [age, 9.7 (SD 0.5) years], 30 adults [23.3 (1.5) years] and 29 seniors [62.7 (6.1) years]. Velocity of COP in medio-lateral and anterior-posterior directions, mean sway frequency in anterior-posterior direction, relative muscle activation (TA and SO) and co-activation revealed large age effects (P < 0.003, η p 2  > 0.14). Post-hoc comparisons indicated higher COP velocities, anterior-posterior frequencies, relative SO activation and co-activation in children and seniors when compared with adults. Relative TA activation was higher in children and adults compared with seniors (P < 0.001). Increased postural sway in children and seniors seems to be counteracted with higher TA/SO co-activity and SO modulation. However, TA modulation is higher in children and adults, whereas seniors' TA modulation capacity is diminished. An aging-induced decline of TA motor units might account for deteriorations of TA modulation in seniors.

Reliability of a Novel High Intensity One Leg Dynamic Exercise Protocol to Measure Muscle Endurance

PubMed Central

Lepers, Romuald; Marcora, Samuele M.

2016-01-01

We recently developed a high intensity one leg dynamic exercise (OLDE) protocol to measure muscle endurance and investigate the central and peripheral mechanisms of muscle fatigue. The aims of the present study were to establish the reliability of this novel protocol and describe the isokinetic muscle fatigue induced by high intensity OLDE and its recovery. Eight subjects performed the OLDE protocol (time to exhaustion test of the right leg at 85% of peak power output) three times over a week period. Isokinetic maximal voluntary contraction torque at 60 (MVC60), 100 (MVC100) and 140 (MVC140) deg/s was measured pre-exercise, shortly after exhaustion (13 ± 4 s), 20 s (P20) and 40 s (P40) post-exercise. Electromyographic (EMG) signal was analyzed via the root mean square (RMS) for all three superficial knee extensors. Mean time to exhaustion was 5.96 ± 1.40 min, coefficient of variation was 8.42 ± 6.24%, typical error of measurement was 0.30 min and intraclass correlation was 0.795. MVC torque decreased shortly after exhaustion for all angular velocities (all P < 0.001). MVC60 and MVC100 recovered between P20 (P < 0.05) and exhaustion and then plateaued. MVC140 recovered only at P40 (P < 0.05). High intensity OLDE did not alter maximal EMG RMS of the three superficial knee extensors during MVC. The results of this study demonstrate that this novel high intensity OLDE protocol could be reliably used to measure muscle endurance, and that muscle fatigue induced by high intensity OLDE should be examined within ~ 30 s following exhaustion. PMID:27706196

The effect of age and unilateral leg immobilization for 2 weeks on substrate utilization during moderate‐intensity exercise in human skeletal muscle

PubMed Central

Gram, M.; Dybboe, R.; Kuhlman, A. B.; Prats, C.; Greenhaff, P. L.; Constantin‐Teodosiu, D.; Birk, J. B.; Wojtaszewski, J. F. P.; Dela, F.; Helge, J. W.

2016-01-01

Key points This study aimed to provide molecular insight into the differential effects of age and physical inactivity on the regulation of substrate metabolism during moderate‐intensity exercise.Using the arteriovenous balance technique, we studied the effect of immobilization of one leg for 2 weeks on leg substrate utilization in young and older men during two‐legged dynamic knee‐extensor moderate‐intensity exercise, as well as changes in key proteins in muscle metabolism before and after exercise.Age and immobilization did not affect relative carbohydrate and fat utilization during exercise, but the older men had higher uptake of exogenous fatty acids, whereas the young men relied more on endogenous fatty acids during exercise.Using a combined whole‐leg and molecular approach, we provide evidence that both age and physical inactivity result in intramuscular lipid accumulation, but this occurs only in part through the same mechanisms. Abstract Age and inactivity have been associated with intramuscular triglyceride (IMTG) accumulation. Here, we attempt to disentangle these factors by studying the effect of 2 weeks of unilateral leg immobilization on substrate utilization across the legs during moderate‐intensity exercise in young (n = 17; 23 ± 1 years old) and older men (n = 15; 68 ± 1 years old), while the contralateral leg served as the control. After immobilization, the participants performed two‐legged isolated knee‐extensor exercise at 20 ± 1 W (∼50% maximal work capacity) for 45 min with catheters inserted in the brachial artery and both femoral veins. Biopsy samples obtained from vastus lateralis muscles of both legs before and after exercise were used for analysis of substrates, protein content and enzyme activities. During exercise, leg substrate utilization (respiratory quotient) did not differ between groups or legs. Leg fatty acid uptake was greater in older than in young men, and although young men demonstrated net

Muscle sympathetic nerve responses to passive and active one-legged cycling: insights into the contributions of central command.

PubMed

Doherty, Connor J; Incognito, Anthony V; Notay, Karambir; Burns, Matthew J; Slysz, Joshua T; Seed, Jeremy D; Nardone, Massimo; Burr, Jamie F; Millar, Philip J

2018-01-01

The contribution of central command to the peripheral vasoconstrictor response during exercise has been investigated using primarily handgrip exercise. The purpose of the present study was to compare muscle sympathetic nerve activity (MSNA) responses during passive (involuntary) and active (voluntary) zero-load cycling to gain insights into the effects of central command on sympathetic outflow during dynamic exercise. Hemodynamic measurements and contralateral leg MSNA (microneurography) data were collected in 18 young healthy participants at rest and during 2 min of passive and active zero-load one-legged cycling. Arterial baroreflex control of MSNA burst occurrence and burst area were calculated separately in the time domain. Blood pressure and stroke volume increased during exercise ( P < 0.0001) but were not different between passive and active cycling ( P > 0.05). In contrast, heart rate, cardiac output, and total vascular conductance were greater during the first and second minute of active cycling ( P < 0.001). MSNA burst frequency and incidence decreased during passive and active cycling ( P < 0.0001), but no differences were detected between exercise modes ( P > 0.05). Reductions in total MSNA were attenuated during the first ( P < 0.0001) and second ( P = 0.0004) minute of active compared with passive cycling, in concert with increased MSNA burst amplitude ( P = 0.02 and P = 0.005, respectively). The sensitivity of arterial baroreflex control of MSNA burst occurrence was lower during active than passive cycling ( P = 0.01), while control of MSNA burst strength was unchanged ( P > 0.05). These results suggest that central feedforward mechanisms are involved primarily in modulating the strength, but not the occurrence, of a sympathetic burst during low-intensity dynamic leg exercise. NEW & NOTEWORTHY Muscle sympathetic nerve activity burst frequency decreased equally during passive and active cycling, but reductions in total muscle sympathetic nerve

Validity of measurement of shear modulus by ultrasound shear wave elastography in human pennate muscle.

PubMed

Miyamoto, Naokazu; Hirata, Kosuke; Kanehisa, Hiroaki; Yoshitake, Yasuhide

2015-01-01

Ultrasound shear wave elastography is becoming a valuable tool for measuring mechanical properties of individual muscles. Since ultrasound shear wave elastography measures shear modulus along the principal axis of the probe (i.e., along the transverse axis of the imaging plane), the measured shear modulus most accurately represents the mechanical property of the muscle along the fascicle direction when the probe's principal axis is parallel to the fascicle direction in the plane of the ultrasound image. However, it is unclear how the measured shear modulus is affected by the probe angle relative to the fascicle direction in the same plane. The purpose of the present study was therefore to examine whether the angle between the principal axis of the probe and the fascicle direction in the same plane affects the measured shear modulus. Shear modulus in seven specially-designed tissue-mimicking phantoms, and in eleven human in-vivo biceps brachii and medial gastrocnemius were determined by using ultrasound shear wave elastography. The probe was positioned parallel or 20° obliquely to the fascicle across the B-mode images. The reproducibility of shear modulus measurements was high for both parallel and oblique conditions. Although there was a significant effect of the probe angle relative to the fascicle on the shear modulus in human experiment, the magnitude was negligibly small. These findings indicate that the ultrasound shear wave elastography is a valid tool for evaluating the mechanical property of pennate muscles along the fascicle direction.

Leg extensor muscle strength, postural stability, and fear of falling after a 2-month home exercise program in women with severe knee joint osteoarthritis.

PubMed

Rätsepsoo, Monika; Gapeyeva, Helena; Sokk, Jelena; Ereline, Jaan; Haviko, Tiit; Pääsuke, Mati

2013-01-01

BACKGROUND AND OBJECTIVE. The aim of this study was to compare the leg extensor muscle strength, the postural stability, and the fear of falling in the women with severe knee joint osteoarthritis (OA) before and after a 2-month home exercise program (HEP). MATERIAL AND METHODS. In total, 17 women aged 46-72 years with late-stage knee joint OA scheduled for total knee arthroplasty participated in this study before and after the 2-month HEP with strengthening, stretching, balance, and step exercises. The isometric peak torque (PT) of the leg extensors and postural stability characteristics when standing on a firm or a foam surface for 30 seconds were recorded. The fear of falling and the pain intensity (VAS) were estimated. RESULTS. A significant increase in the PT and the PT-to-body weight (PT-to-BW) ratio of the involved leg as well as the bilateral PT and the PT-to-BW ratio was found after the 2-month HEP compared with the data before the HEP (P<0.05). The PT and the PT-to-BW ratio of the involved leg were significantly lower compared with the uninvolved leg before the HEP (P<0.05). The center of the pressure sway length (foam surface) decreased significantly after the HEP (P<0.05). Significant correlations were found between the PT of the involved leg and the bilateral PT and the fear of falling and between the PT of the involved leg and the postural sway (foam surface) before the HEP. CONCLUSIONS. After the 2-month HEP, the leg extensor muscle strength increased and the postural sway length on a foam surface decreased. The results indicate that the increased leg extensor muscle strength improves postural stability and diminishes the fear of falling in women with late-stage knee joint OA.

Rehabilitative ultrasound measurement of trapezius muscle contractile states in people with mild shoulder pain.

PubMed

O'Sullivan, Cliona; McCarthy Persson, Ulrik; Blake, Catherine; Stokes, Maria

2012-04-01

The utility of rehabilitative ultrasound imaging (RUSI) for assessing trapezius muscle contractile characteristics was investigated by examining whether muscle thickness changes during contraction (CT) differed between people with and without mild shoulder pain. In 18 subjects with mild shoulder pain (aged 28±8 years) and 18 matched controls, trapezius muscle thickness change was measured in prone at rest at 0° and during isometric CTs at 90° and 120° of shoulder abduction. Images were taken at four sites using a real-time ultrasound scanner (7-MHz linear transducer, 40 mm footprint). Percentage change in muscle thickness from rest was calculated. Differences between painful and non-painful shoulders and participant groups were examined by analysis of variance (ANOVA) and t-tests. There were no significant differences between groups or sides in trapezius muscle thickness change during CT. There was no significant difference in trapezius muscle resting thickness (RT) between painful and non-painful shoulders in the same subjects. Contractile ability of the trapezius muscle, assessed using RUSI was not impaired in subjects with mild shoulder pain during the test manoeuvres used. Further research is warranted involving patients with different severity of symptoms, using other test manoeuvres before RUSI can be advocated for assessing scapular muscle dysfunction. Copyright © 2011 Elsevier Ltd. All rights reserved.

Contributions of Hamstring Stiffness to Straight-Leg-Raise and Sit-and-Reach Test Scores.

PubMed

Miyamoto, Naokazu; Hirata, Kosuke; Kimura, Noriko; Miyamoto-Mikami, Eri

2018-02-01

The passive straight-leg-raise (PSLR) and the sit-and-reach (SR) tests have been widely used to assess hamstring extensibility. However, it remains unclear to what extent hamstring stiffness (a measure of material properties) contributes to PSLR and SR test scores. Therefore, we aimed to clarify the relationship between hamstring stiffness and PSLR and SR scores using ultrasound shear wave elastography. Ninety-eight healthy subjects completed the study. Each subject completed PSLR testing, and classic and modified SR testing of the right leg. Muscle shear modulus of the biceps femoris, semitendinosus, and semimembranosus was quantified as an index of muscle stiffness. The relationships between shear modulus of each muscle and PSLR or SR scores were calculated using Pearson's product-moment correlation coefficients. Shear modulus of the semitendinosus and semimembranosus showed negative correlations with the two PSLR and two SR scores (absolute r value≤0.484). Shear modulus of the biceps femoris was significantly correlated with the PSLR score determined by the examiner and the modified SR score (absolute r value≤0.308). The present findings suggest that PSLR and SR test scores are strongly influenced by factors other than hamstring stiffness and therefore might not accurately evaluate hamstring stiffness. © Georg Thieme Verlag KG Stuttgart · New York.

Four weeks one-leg training and high fat diet does not alter PPARalpha protein or mRNA expression in human skeletal muscle.

PubMed

Helge, J W; Bentley, D; Schjerling, P; Willer, M; Gibala, M J; Franch, J; Tapia-Laliena, M A; Daugaard, J R; Andersen, J L

2007-09-01

Fatty acid metabolism is influenced by training and diet with exercise training mediating this through activation of nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARalpha) in skeletal muscle. This study investigated the effect of training and high fat or normal diet on PPARalpha expression in human skeletal muscle. Thirteen men trained one leg (T) four weeks (31.5 h in total), while the other leg (UT) served as control. During the 4 weeks six subjects consumed high fat (FAT) diet and seven subjects maintained a normal (CHO) diet. Biopsies were obtained from vastus lateralis muscle in both legs before and after training. After the biopsy, one-leg extension exercise was performed in random order with both legs 30 min at 95% of workload max. A training effect was evident as citrate synthase activity increased (P < 0.05) by 15% in the trained, but not the control leg in both groups. During exercise respiratory exchange ratio was lower in FAT (0.86 +/- 0.01, 0.83 +/- 0.01, mean +/- SEM) than CHO (0.96 +/- 0.02, 0.94 +/- 0.03) and in UT than T legs, respectively. The PPARalpha protein (144 +/- 44, 104 +/- 28, 79 +/- 15, 79 +/- 14, % of pre level) and PPARalpha mRNA (69 +/- [2, 2], 78 +/- [7, 6], 92 +/- [22, 18], 106 +/- [21, 18], % of pre level, geometric mean +/- SEM) expression remained unchanged by diet and training in FAT (UT, T) and CHO (UT, T), respectively. After the training and diet CS, HAD, PPARalpha, UCP2, UCP3 and mFABP mRNA content remained unchanged, whereas GLUT4 mRNA was lower in both groups and LDHA mRNA was lower (P < 0.05) only in FAT. 4 weeks one leg knee extensor training did not affect PPARalpha protein or mRNA expression. Furthermore, higher fat oxidation during exercise after fat rich diet was not accompanied by an increased PPARalpha protein or mRNA expression after 4 weeks.

Quantitative muscle ultrasound in Duchenne muscular dystrophy: a comparison of techniques.

PubMed

Shklyar, Irina; Geisbush, Tom R; Mijialovic, Aleksandar S; Pasternak, Amy; Darras, Basil T; Wu, Jim S; Rutkove, Seward B; Zaidman, Craig M

2015-02-01

Muscle pathology in Duchenne muscular dystrophy (DMD) can be quantified using ultrasound by measuring either the amplitudes of sound-waves scattered back from the tissue [quantitative backscatter analysis (QBA)] or by measuring these backscattered amplitudes after compression into grayscale levels (GSL) obtained from the images. We measured and compared QBA and GSL from 6 muscles of 25 boys with DMD and 25 healthy subjects, aged 2-14 years, with age and, in DMD, with function (North Star Ambulatory Assessment). Both QBA and GSL were measured reliably (intraclass correlation ≥ 0.87) and were higher in DMD than controls (P < 0.0001). In DMD, average QBA and GSL measured from superficial regions of muscle increased (rho ≥ 0.47, P < 0.05) with both higher age and worse function; in contrast, GSL measured from whole regions of muscle did not. QBA and GSL measured from superficial regions of muscle can similarly quantify muscle pathology in DMD. © 2014 Wiley Periodicals, Inc.

Synthesis of amino acids in weight bearing and non-weight bearing leg muscles of suspended rats

NASA Technical Reports Server (NTRS)

Tischler, M. E.; Jaspers, S. R.

1982-01-01

The effect of hypokinesia (HYP) for 6 days on the de novo synthesis of glutamine (GLN) and glutamate (GLU), and of alanine was tested in isolated leg muscles of intact, adrenalectomized (ADX) and ADX cortisol-treated rats. The net synthesis of GLN and GLU was lower in soleus muscles of HYP animals of these three groups of rats. The synthesis of alanine was lowered by HYP in ADX animals and apparently raised by HYP in ADX cortisol-treated rats. No HYP effect was seen in the extensor digitorum longus (EDL) muscles of these animals. Although ADX lowered the synthesis of GLN and GLU in soleus muscles of control rats, while cortisol treatment restored this process to near normal, neither ADX nor cortisol treatment produced any effect in the HYP animals. However, effects of ADX and cortisol treatment on synthesis of GLN and GLU in EDL muscles and of alanine in both muscles seemed normal in HYP animals.

Comparison of clinical marking and ultrasound-guided injection of Botulinum type A toxin into the masseter muscles for treating bruxism and its cosmetic effects.

PubMed

Quezada-Gaon, Natacha; Wortsman, Ximena; Peñaloza, Osvaldo; Carrasco, Juan Eduardo

2016-09-01

Botulinum toxin type A has been used for treating the hypertrophy of the masseter muscles and its cosmetic effects. Ultrasound is increasingly used in dermatology, along with the guidance of mini-invasive procedures. To evaluate the role of ultrasound for guiding the application of Botulinum A toxin in patients with cosmetic alterations due to bruxism, correlate the clinical landmarks with the ultrasound findings, and study the effect on the symptoms, cosmetics, and quality of life. Twenty individuals with bruxism and cosmetic alterations underwent an ultrasound-guided injection of Botulinum toxin type A in each masseter muscle. Clinical and ultrasound marking of the procedure was compared. Clinical and sonographic evaluation was performed at the time of injection and 3 months later. Ten normal individuals underwent ultrasound of the masseter muscles as a control group. Up to 65% of individuals showed anatomical variants of the salivary glands. The method for clinically marking the skin showed a frequently erroneous location of the anterior point (up to 40% of cases) that was proven by ultrasound to be out of the muscle. In 20% of cases, ultrasound showed that the needle should be longer to enter the muscle. After injection, most of the patients demonstrated a decrease of the symptoms and cosmetic and quality of life improvements. Ultrasound can be a potent tool for guiding the injection of Botulinum toxin into the masseter muscles. It may contribute to a more personalized procedure, better cosmetic results, and help to avoid potential complications. © 2016 Wiley Periodicals, Inc.

Therapeutic Pulsed Ultrasound Promotes Revascularization and Functional Recovery of Rat Skeletal Muscle after Contusion Injury.

PubMed

Chongsatientam, Areeya; Yimlamai, Tossaporn

2016-12-01

The mechanism by which therapeutic pulsed ultrasound (TPU) promotes the repair of damaged gastrocnemius muscle was investigated. Male Wistar rats were divided into uninjured, sham-treated injured and TPU-treated injured (TPU) groups. Injury was induced by mass-drop technique. TPU was applied to the injured muscle for 5 min, daily, started at day 1 post-injury and continuing for 3, 7 and 14 d. For 3 d post-injury, a significant reduction in muscle force was observed in both the sham-treated injured and TPU groups. TPU treatment significantly increased recovery force of the injured muscle after day 7 post-injury. This effect of TPU is associated with increased centronucleated fibers and cross-sectional area, mRNA expression of the vascular endothelial growth factor and capillary density of the regenerated fibers, but not with mRNA expression of nitric oxide synthase. We conclude that TPU hastens muscle recovery, at least in part, by upregulating angiogenesis. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Comparison of human gastrocnemius forces predicted by Hill-type muscle models and estimated from ultrasound images

PubMed Central

Biewener, Andrew A.; Wakeling, James M.

2017-01-01

ABSTRACT Hill-type models are ubiquitous in the field of biomechanics, providing estimates of a muscle's force as a function of its activation state and its assumed force–length and force–velocity properties. However, despite their routine use, the accuracy with which Hill-type models predict the forces generated by muscles during submaximal, dynamic tasks remains largely unknown. This study compared human gastrocnemius forces predicted by Hill-type models with the forces estimated from ultrasound-based measures of tendon length changes and stiffness during cycling, over a range of loads and cadences. We tested both a traditional model, with one contractile element, and a differential model, with two contractile elements that accounted for independent contributions of slow and fast muscle fibres. Both models were driven by subject-specific, ultrasound-based measures of fascicle lengths, velocities and pennation angles and by activation patterns of slow and fast muscle fibres derived from surface electromyographic recordings. The models predicted, on average, 54% of the time-varying gastrocnemius forces estimated from the ultrasound-based methods. However, differences between predicted and estimated forces were smaller under low speed–high activation conditions, with models able to predict nearly 80% of the gastrocnemius force over a complete pedal cycle. Additionally, the predictions from the Hill-type muscle models tested here showed that a similar pattern of force production could be achieved for most conditions with and without accounting for the independent contributions of different muscle fibre types. PMID:28202584

The effect of age and unilateral leg immobilization for 2 weeks on substrate utilization during moderate-intensity exercise in human skeletal muscle.

PubMed

Vigelsø, A; Gram, M; Dybboe, R; Kuhlman, A B; Prats, C; Greenhaff, P L; Constantin-Teodosiu, D; Birk, J B; Wojtaszewski, J F P; Dela, F; Helge, J W

2016-04-15

This study aimed to provide molecular insight into the differential effects of age and physical inactivity on the regulation of substrate metabolism during moderate-intensity exercise. Using the arteriovenous balance technique, we studied the effect of immobilization of one leg for 2 weeks on leg substrate utilization in young and older men during two-legged dynamic knee-extensor moderate-intensity exercise, as well as changes in key proteins in muscle metabolism before and after exercise. Age and immobilization did not affect relative carbohydrate and fat utilization during exercise, but the older men had higher uptake of exogenous fatty acids, whereas the young men relied more on endogenous fatty acids during exercise. Using a combined whole-leg and molecular approach, we provide evidence that both age and physical inactivity result in intramuscular lipid accumulation, but this occurs only in part through the same mechanisms. Age and inactivity have been associated with intramuscular triglyceride (IMTG) accumulation. Here, we attempt to disentangle these factors by studying the effect of 2 weeks of unilateral leg immobilization on substrate utilization across the legs during moderate-intensity exercise in young (n = 17; 23 ± 1 years old) and older men (n = 15; 68 ± 1 years old), while the contralateral leg served as the control. After immobilization, the participants performed two-legged isolated knee-extensor exercise at 20 ± 1 W (∼50% maximal work capacity) for 45 min with catheters inserted in the brachial artery and both femoral veins. Biopsy samples obtained from vastus lateralis muscles of both legs before and after exercise were used for analysis of substrates, protein content and enzyme activities. During exercise, leg substrate utilization (respiratory quotient) did not differ between groups or legs. Leg fatty acid uptake was greater in older than in young men, and although young men demonstrated net leg glycerol release during

Acute cocoa flavanol supplementation improves muscle macro- and microvascular but not anabolic responses to amino acids in older men.

PubMed

Phillips, Bethan E; Atherton, Philip J; Varadhan, Krishna; Limb, Marie C; Williams, John P; Smith, Kenneth

2016-05-01

The anabolic effects of nutrition on skeletal muscle may depend on adequate skeletal muscle perfusion, which is impaired in older people. Cocoa flavanols have been shown to improve flow-mediated dilation, an established measure of endothelial function. However, their effect on muscle microvascular blood flow is currently unknown. Therefore, the objective of this study was to explore links between the consumption of cocoa flavanols, muscle microvascular blood flow, and muscle protein synthesis (MPS) in response to nutrition in older men. To achieve this objective, leg blood flow (LBF), muscle microvascular blood volume (MBV), and MPS were measured under postabsorptive and postprandial (intravenous Glamin (Fresenius Kabi, Germany), dextrose to sustain glucose ∼7.5 mmol·L(-1)) conditions in 20 older men. Ten of these men were studied with no cocoa flavanol intervention and a further 10 were studied with the addition of 350 mg of cocoa flavanols at the same time that nutrition began. Leg (femoral artery) blood flow was measured by Doppler ultrasound, muscle MBV by contrast-enhanced ultrasound using Definity (Lantheus Medical Imaging, Mass., USA) perflutren contrast agent and MPS using [1, 2-(13)C2]leucine tracer techniques. Our results show that although older individuals do not show an increase in LBF or MBV in response to feeding, these absent responses are apparent when cocoa flavanols are given acutely with nutrition. However, this restoration in vascular responsiveness is not associated with improved MPS responses to nutrition. We conclude that acute cocoa flavanol supplementation improves muscle macro- and microvascular responses to nutrition, independently of modifying muscle protein anabolism.

Improvement in upper leg muscle strength underlies beneficial effects of exercise therapy in knee osteoarthritis: secondary analysis from a randomised controlled trial.

PubMed

Knoop, J; Steultjens, M P M; Roorda, L D; Lems, W F; van der Esch, M; Thorstensson, C A; Twisk, J W R; Bierma-Zeinstra, S M A; van der Leeden, M; Dekker, J

2015-06-01

Although exercise therapy is effective for reducing pain and activity limitations in patients with knee osteoarthritis (OA), the underlying mechanisms are unclear. This study aimed to evaluate if improvements in neuromuscular factors (i.e. upper leg muscle strength and knee proprioception) underlie the beneficial effects of exercise therapy in patients with knee OA. Secondary analyses from a randomised controlled trial, with measurements at baseline, 6 weeks, 12 weeks and 38 weeks. Rehabilitation centre. One hundred and fifty-nine patients diagnosed with knee OA. Exercise therapy. Changes in pain [numeric rating scale (NRS)] and activity limitations [Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale and get-up-and-go test] during the study period. Independent variables were changes in upper leg muscle strength and knee joint proprioception (i.e. motion sense) during the study period. Longitudinal regression analyses (generalised estimating equation) were performed to analyse associations between changes in upper leg muscle strength and knee proprioception with changes in pain and activity limitations. Improved muscle strength was significantly associated with reductions in NRS pain {B coefficient -2.5 [95% confidence interval (CI) -3.7 to -1.4], meaning that every change of 1 unit of strength was linked to a change of -2.5 units of pain}, WOMAC physical function (-8.8, 95% CI -13.4 to -4.2) and get-up-and-go test (-1.7, 95% CI -2.4 to -1.0). Improved proprioception was not significantly associated with better outcomes of exercise therapy (P>0.05). Upper leg muscle strengthening is one of the mechanisms underlying the beneficial effects of exercise therapy in patients with knee OA. Copyright © 2014 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Cardiovascular control during concomitant dynamic leg exercise and static arm exercise in humans

PubMed Central

Strange, S

1999-01-01

Skeletal muscle blood flow is thought to be determined by a balance between sympathetic vasoconstriction and metabolic vasodilatation. The purpose of this study was to assess the importance of high levels of sympathetic vasoconstrictor activity in control of blood flow to human skeletal muscle during dynamic exercise.Muscle sympathetic nerve activity to the exercising leg was increased by static or static ischaemic arm exercise added to on-going dynamic leg exercise. Ten subjects performed light (20 W) or moderate (40 W) dynamic knee extension for 6 min with one leg alone or concomitant with bilateral static handgrip at 20% of maximal voluntary contraction force with or without forearm muscle ischaemia or post-exercise forearm muscle ischaemia.Muscle sympathetic nerve activity was measured by microneurography (peroneal nerve) and leg muscle blood flow by a constant infusion thermodilution technique (femoral vein).Activation of an exercise pressor reflex from the arms, causing a 2- to 4-fold increase in muscle sympathetic nerve activity and a 15–32% increase in mean arterial blood pressure, did not affect blood flow to the dynamically exercising leg muscles at any level of leg exercise. Leg vascular conductance was reduced in line with the higher perfusion pressure.The results demonstrate that the vasoconstrictor effects of high levels of muscle sympathetic nerve activity does not affect blood flow to human skeletal muscle exercising at moderate intensities. One question remaining is whether the observed decrease in muscle vascular conductance is the result of sympathetic vasoconstriction or metabolic autoregulation of muscle blood flow. PMID:9831733

Relationship between isometric contraction intensity and muscle hardness assessed by ultrasound strain elastography.

PubMed

Inami, Takayuki; Tsujimura, Toru; Shimizu, Takuya; Watanabe, Takemasa; Lau, Wing Yin; Nosaka, Kazunori

2017-05-01

Ultrasound elastography is used to assess muscle hardness or stiffness; however, no previous studies have validated muscle hardness measures using ultrasound strain elastography (SE). This study investigated the relationship between plantar flexor isometric contraction intensity and gastrocnemius hardness assessed by SE. We hypothesised that the muscle would become harder linearly with an increase in the contraction intensity of the plantar flexors. Fifteen young women (20.1 ± 0.8 years) performed isometric contractions of the ankle plantar flexors at four different intensities (25, 50, 75, 100% of maximal voluntary contraction force: MVC) at 0° plantar flexion. Using SE images, the strain ratio (SR) between the muscle and an acoustic coupler (elastic modulus 22.6 kPa) placed over the skin was calculated (muscle/coupler); pennation angle and muscle thickness were measured for the resting and contracting conditions. SR decreased with increasing contraction intensity from rest (1.28 ± 0.20) to 25% (0.99 ± 0.21), 50% (0.61 ± 0.15), 75% (0.34 ± 0.1) and 100% MVC (0.20 ± 0.05). SR decreased linearly (P < 0.05) with increasing MVC from rest to 75% MVC, but levelled off from 75 and 100% MVC. SR was negatively correlated with pennation angle (r = -0.80, P < 0.01) and muscle thickness ( r= -0.78,  P< 0.01). SR appears to represent muscle hardness changes in response to contraction intensity changes, in the assumption that the gastrocnemius muscle contraction intensity is proportional to the plantar flexion intensity. We concluded that gastrocnemius muscle hardness changes could be validly assessed by SR, and the force-hardness relationship was not linear.

T2 mapping provides multiple approaches to characterize muscle involvement in neuromuscular diseases: a cross-sectional study of lower leg muscles in 5–15 year old boys with Duchenne Muscular Dystrophy

PubMed Central

Arpan, Ishu; Forbes, Sean C; Lott, Donovan J; Senesac, Claudia R; Daniels, Michael J; Triplett, William T; Deol, Jasjit K; Sweeney, H Lee; Walter, Glenn A; Vandenborne, Krista

2012-01-01

Purpose Skeletal muscles of children with Duchenne muscular dystrophy (DMD) have enhanced susceptibility to damage and progressive lipid infiltration, which contribute to an increase in magnetic resonance proton transverse relaxation time (T2). Therefore, examining T2 changes in individual muscles may be useful for monitoring disease progression in DMD. In this study we utilized mean T2, percent elevated pixels, and T2 heterogeneity to assess changes in composition of dystrophic muscles. In addition, we used fat saturation (fatsat) to distinguish T2 changes due to edema and inflammation from fat infiltration in muscles. Methods Thirty subjects with DMD and 15 age-matched controls underwent T2-weighted imaging of their lower leg using 3-T MR system. T2 maps were developed and four lower leg muscles were manually traced (soleus, medial gastrocnemius, peroneal and tibialis anterior). Mean T2 of the traced regions of interest (ROI), width of T2 histograms, and percent-elevated pixels were calculated. Results We found that even in young children with DMD, muscles had elevated mean T2, were more heterogeneous, and had a greater percent-elevated pixels in the lower leg muscles than controls. T2 measures decreased with fat saturation, but were still higher (p<0.05) in dystrophic muscles than controls. Further, T2 measures showed positive correlations with timed functional tests (r=0.23–0.79). Conclusion The elevated T2 measures with and without fat saturation in all ages of DMD examined (5–15 years) compared to unaffected controls indicate that the dystrophic muscles have increased regions of damage, edema, and fat infiltration. This study shows that T2 mapping provides multiple approaches that can be effectively utilized to characterize muscle tissue in children with DMD even in the early stages of the disease. Therefore, T2 mapping may prove clinically useful in monitoring muscle changes due to disease process or therapeutic interventions in DMD. PMID:23044995

Validation of Bedside Ultrasound of Muscle Layer Thickness of the Quadriceps in the Critically Ill Patient (VALIDUM Study).

PubMed

Paris, Michael T; Mourtzakis, Marina; Day, Andrew; Leung, Roger; Watharkar, Snehal; Kozar, Rosemary; Earthman, Carrie; Kuchnia, Adam; Dhaliwal, Rupinder; Moisey, Lesley; Compher, Charlene; Martin, Niels; Nicolo, Michelle; White, Tom; Roosevelt, Hannah; Peterson, Sarah; Heyland, Daren K

2017-02-01

In critically ill patients, muscle atrophy is associated with long-term disability and mortality. Bedside ultrasound may quantify muscle mass, but it has not been validated in the intensive care unit (ICU). Here, we compared ultrasound-based quadriceps muscle layer thickness (QMLT) with precise quantifications of computed tomography (CT)-based muscle cross-sectional area (CSA). Patients ≥18 years old with abdominal CT scans performed for clinical reasons were recruited from 9 ICUs for an ultrasound assessment of the quadriceps. CT scans of the third lumbar vertebra, performed <24 hours before or <72 hours after ICU admission, were analyzed for CSA. Low muscularity was defined as 170 cm 2 for men and 110 cm 2 for women. The ultrasound probe was maximally compressed against the skin and QMLT was measured on 2 sites of each quadriceps <72 hours of the CT scan. Mean CT-derived muscle CSA was 109 ± 25 cm 2 for women and 168 ± 37 cm 2 for men, where 58% of patients exhibited low muscularity; only 2.7% patients were underweight according to body mass index. QMLT was positively correlated with CT CSA ( r = 0.45, P < .001). Based on logistic regression to predict low muscularity, QMLT independently generated a concordance index ( c) of 0.67 ( P < .002), which increased to 0.77 ( P < .001) when age, sex, body mass index, Charlson Comorbidity Index, and admission type (surgical vs medical) were added. Our results suggest that QMLT alone with our current protocol may not accurately identify patients with low muscle mass.

Muscle activity and spine load during anterior chain whole body linkage exercises: the body saw, hanging leg raise and walkout from a push-up.

PubMed

McGill, Stuart; Andersen, Jordan; Cannon, Jordan

2015-01-01

This study examined anterior chain whole body linkage exercises, namely the body saw, hanging leg raise and walkout from a push-up. Investigation of these exercises focused on which particular muscles were challenged and the magnitude of the resulting spine load. Fourteen males performed the exercises while muscle activity, external force and 3D body segment motion were recorded. A sophisticated and anatomically detailed 3D model used muscle activity and body segment kinematics to estimate muscle force, and thus sensitivity to each individual's choice of motor control for each task. Gradations of muscle activity and spine load characteristics were observed across tasks. On average, the hanging straight leg raise created approximately 3000 N of spine compression while the body saw created less than 2500 N. The hanging straight leg raise created the highest challenge to the abdominal wall (>130% MVC in rectus abdominis, 88% MVC in external oblique). The body saw resulted in almost 140% MVC activation of the serratus anterior. All other exercises produced substantial abdominal challenge, although the body saw did so in the most spine conserving way. These findings, along with consideration of an individual's injury history, training goals and current fitness level, should assist in exercise choice and programme design.

A comparison of optimisation methods and knee joint degrees of freedom on muscle force predictions during single-leg hop landings.

PubMed

Mokhtarzadeh, Hossein; Perraton, Luke; Fok, Laurence; Muñoz, Mario A; Clark, Ross; Pivonka, Peter; Bryant, Adam L

2014-09-22

The aim of this paper was to compare the effect of different optimisation methods and different knee joint degrees of freedom (DOF) on muscle force predictions during a single legged hop. Nineteen subjects performed single-legged hopping manoeuvres and subject-specific musculoskeletal models were developed to predict muscle forces during the movement. Muscle forces were predicted using static optimisation (SO) and computed muscle control (CMC) methods using either 1 or 3 DOF knee joint models. All sagittal and transverse plane joint angles calculated using inverse kinematics or CMC in a 1 DOF or 3 DOF knee were well-matched (RMS error<3°). Biarticular muscles (hamstrings, rectus femoris and gastrocnemius) showed more differences in muscle force profiles when comparing between the different muscle prediction approaches where these muscles showed larger time delays for many of the comparisons. The muscle force magnitudes of vasti, gluteus maximus and gluteus medius were not greatly influenced by the choice of muscle force prediction method with low normalised root mean squared errors (<48%) observed in most comparisons. We conclude that SO and CMC can be used to predict lower-limb muscle co-contraction during hopping movements. However, care must be taken in interpreting the magnitude of force predicted in the biarticular muscles and the soleus, especially when using a 1 DOF knee. Despite this limitation, given that SO is a more robust and computationally efficient method for predicting muscle forces than CMC, we suggest that SO can be used in conjunction with musculoskeletal models that have a 1 or 3 DOF knee joint to study the relative differences and the role of muscles during hopping activities in future studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Superior mitochondrial adaptations in human skeletal muscle after interval compared to continuous single‐leg cycling matched for total work

PubMed Central

MacInnis, Martin J.; Zacharewicz, Evelyn; Martin, Brian J.; Haikalis, Maria E.; Skelly, Lauren E.; Tarnopolsky, Mark A.; Murphy, Robyn M.

2016-01-01

Key points A classic unresolved issue in human integrative physiology involves the role of exercise intensity, duration and volume in regulating skeletal muscle adaptations to training.We employed counterweighted single‐leg cycling as a unique within‐subject model to investigate the role of exercise intensity in promoting training‐induced increases in skeletal muscle mitochondrial content.Six sessions of high‐intensity interval training performed over 2 weeks elicited greater increases in citrate synthase maximal activity and mitochondrial respiration compared to moderate‐intensity continuous training matched for total work and session duration.These data suggest that exercise intensity, and/or the pattern of contraction, is an important determinant of exercise‐induced skeletal muscle remodelling in humans. Abstract We employed counterweighted single‐leg cycling as a unique model to investigate the role of exercise intensity in human skeletal muscle remodelling. Ten young active men performed unilateral graded‐exercise tests to measure single‐leg V˙O2, peak and peak power (W peak). Each leg was randomly assigned to complete six sessions of high‐intensity interval training (HIIT) [4 × (5 min at 65% W peak and 2.5 min at 20% W peak)] or moderate‐intensity continuous training (MICT) (30 min at 50% W peak), which were performed 10 min apart on each day, in an alternating order. The work performed per session was matched for MICT (143 ± 8.4 kJ) and HIIT (144 ± 8.5 kJ, P > 0.05). Post‐training, citrate synthase (CS) maximal activity (10.2 ± 0.8 vs. 8.4 ± 0.9 mmol kg protein−1 min−1) and mass‐specific [pmol O2•(s•mg wet weight)−1] oxidative phosphorylation capacities (complex I: 23.4 ± 3.2 vs. 17.1 ± 2.8; complexes I and II: 58.2 ± 7.5 vs. 42.2 ± 5.3) were greater in HIIT relative to MICT (interaction effects, P < 0.05); however, mitochondrial function [i.e. pmol O2•(s•CS maximal

Ultrasound-mediated gene delivery of naked plasmid DNA in skeletal muscles: a case for bolus injections.

PubMed

Sanches, Pedro Gomes; Mühlmeister, Mareike; Seip, Ralf; Kaijzel, Eric; Löwik, Clemens; Böhmer, Marcel; Tiemann, Klaus; Grüll, Holger

2014-12-10

Localized gene delivery has many potential clinical applications. However, the nucleic acids (e.g. pDNA and siRNA) are incapable of passively crossing the endothelium, cell membranes and other biological barriers which must be crossed to reach their intracellular targets. A possible solution is the use of ultrasound to burst circulating microbubbles inducing transient permeabilization of surrounding tissues which mediates nucleic acid extravasation and cellular uptake. In this study we report on an optimization of the ultrasound gene delivery technique. Naked pDNA (200 μg) encoding luciferase and SonoVue® microbubbles were co-injected intravenously in mice. The hindlimb skeletal muscles were exposed to ultrasound from a non-focused transducer (1 MHz, 1.25 MPa, PRI 30s) and injection protocols and total amounts as well as ultrasound parameters were systemically varied. Gene expression was quantified relative to a control using a bioluminescence camera system at day 7 after sonication. Bioluminescence ratios in sonicated/control muscles of up to 101× were obtained. In conclusion, we were able to specifically deliver genetic material to the selected skeletal muscles and overall, the use of bolus injections and high microbubble numbers resulted in increased gene expression reflected by stronger bioluminescence signals. Based on our data, bolus injections seem to be required in order to achieve transient highly concentrated levels of nucleic acids and microbubbles at the tissue of interest which upon ultrasound exposure should lead to increased levels of gene delivery. Thus, ultrasound mediated gene delivery is a promising technique for the clinical translation of localized drug delivery. Copyright © 2014 Elsevier B.V. All rights reserved.

T₂ mapping provides multiple approaches for the characterization of muscle involvement in neuromuscular diseases: a cross-sectional study of lower leg muscles in 5-15-year-old boys with Duchenne muscular dystrophy.

PubMed

Arpan, Ishu; Forbes, Sean C; Lott, Donovan J; Senesac, Claudia R; Daniels, Michael J; Triplett, William T; Deol, Jasjit K; Sweeney, H Lee; Walter, Glenn A; Vandenborne, Krista

2013-03-01

Skeletal muscles of children with Duchenne muscular dystrophy (DMD) show enhanced susceptibility to damage and progressive lipid infiltration, which contribute to an increase in the MR proton transverse relaxation time (T₂). Therefore, the examination of T₂ changes in individual muscles may be useful for the monitoring of disease progression in DMD. In this study, we used the mean T₂, percentage of elevated pixels and T₂ heterogeneity to assess changes in the composition of dystrophic muscles. In addition, we used fat saturation to distinguish T₂ changes caused by edema and inflammation from fat infiltration in muscles. Thirty subjects with DMD and 15 age-matched controls underwent T₂ -weighted imaging of their lower leg using a 3-T MR system. T₂ maps were developed and four lower leg muscles were manually traced (soleus, medial gastrocnemius, peroneal and tibialis anterior). The mean T₂ of the traced regions of interest, width of the T₂ histograms and percentage of elevated pixels were calculated. We found that, even in young children with DMD, lower leg muscles showed elevated mean T₂, were more heterogeneous and had a greater percentage of elevated pixels than in controls. T₂ measures decreased with fat saturation, but were still higher (P < 0.05) in dystrophic muscles than in controls. Further, T₂ measures showed positive correlations with timed functional tests (r = 0.23-0.79). The elevated T₂ measures with and without fat saturation at all ages of DMD examined (5-15 years) compared with unaffected controls indicate that the dystrophic muscles have increased regions of damage, edema and fat infiltration. This study shows that T₂ mapping provides multiple approaches that can be used effectively to characterize muscle tissue in children with DMD, even in the early stages of the disease. Therefore, T₂ mapping may prove to be clinically useful in the monitoring of muscle changes caused by the disease process or by therapeutic

Comparison of human gastrocnemius forces predicted by Hill-type muscle models and estimated from ultrasound images.

PubMed

Dick, Taylor J M; Biewener, Andrew A; Wakeling, James M

2017-05-01

Hill-type models are ubiquitous in the field of biomechanics, providing estimates of a muscle's force as a function of its activation state and its assumed force-length and force-velocity properties. However, despite their routine use, the accuracy with which Hill-type models predict the forces generated by muscles during submaximal, dynamic tasks remains largely unknown. This study compared human gastrocnemius forces predicted by Hill-type models with the forces estimated from ultrasound-based measures of tendon length changes and stiffness during cycling, over a range of loads and cadences. We tested both a traditional model, with one contractile element, and a differential model, with two contractile elements that accounted for independent contributions of slow and fast muscle fibres. Both models were driven by subject-specific, ultrasound-based measures of fascicle lengths, velocities and pennation angles and by activation patterns of slow and fast muscle fibres derived from surface electromyographic recordings. The models predicted, on average, 54% of the time-varying gastrocnemius forces estimated from the ultrasound-based methods. However, differences between predicted and estimated forces were smaller under low speed-high activation conditions, with models able to predict nearly 80% of the gastrocnemius force over a complete pedal cycle. Additionally, the predictions from the Hill-type muscle models tested here showed that a similar pattern of force production could be achieved for most conditions with and without accounting for the independent contributions of different muscle fibre types. © 2017. Published by The Company of Biologists Ltd.

Net joint moments and muscle activation in barbell squats without and with restricted anterior leg rotation.

PubMed

Chiu, Loren Z F; vonGaza, Gabriella L; Jean, Liane M Y

2017-01-01

Muscle utilisation in squat exercise depends on technique. The purpose of this study was to compare net joint moments (NJMs) and muscle activation during squats without and with restricted leg dorsiflexion. Experienced men (n = 5) and women (n = 4) performed full squats at 80% one repetition maximum. 3D motion analysis, force platform and (EMG) data were collected. Restricting anterior leg rotation reduced anterior leg (P = 0.001) and posterior thigh (P < 0.001) rotations, resulting in a smaller knee flexion range of motion (P < 0.001). At maximum squat depth, ankle plantar flexor (P < 0.001) and knee extensor (P < 0.001) NJM were higher in unrestricted squats. Hip extensor NJM (P = 0.14) was not different between squat types at maximum squat depth. Vastus lateralis (P > 0.05), vastus medialis (P > 0.05) and rectus femoris (P > 0.05) EMG were not different between squat types. Unrestricted squats have higher ankle plantar flexor and knee extensor NJM than previously reported from jumping and landing. However, ankle plantar flexor and knee extensor NJM are lower in restricted squats than previous studies of jumping and landing. The high NJM in unrestricted squat exercise performed through a full range of motion suggests this squat type would be more effective to stimulate adaptations in the lower extremity musculature than restricted squats.

Effects of wearing lower leg compression sleeves on locomotion economy.

PubMed

Kurz, Eduard; Anders, Christoph

2018-09-01

The purpose of this investigation was to assess the effect of compression sleeves on muscle activation cost during locomotion. Twenty-two recreationally active men (age: 25 ± 3 years) ran on a treadmill at four different speeds (ordered sequence of 2.8, 3.3, 2.2, and 3.9 m/s). The tests were performed without (control situation, CON) and while wearing specially designed lower leg compression sleeves (SL). Myoelectric activity of five lower leg muscles (tibialis anterior, fibularis longus, lateral and medial head of gastrocnemius, and soleus) was captured using Surface EMG. To assess muscle activation cost, the cumulative muscle activity per distance travelled (CMAPD) of the CON and SL situations was determined. Repeated measures analyses of variance were performed separately for each muscle. The analyses revealed a reduced lower leg muscle activation cost with respect to test situation for SL for all muscles (p < 0.05, η p 2  > 0.18). The respective significant reductions of CMAPD values during SL ranged between 4% and 16% and were largest at 2.8 m/s. The findings presented point towards an improved muscle activation cost while wearing lower leg compression sleeves during locomotion that have potential to postpone muscle fatigue.

Carotid baroreflex control of leg vasculature in exercising and non-exercising skeletal muscle in humans

PubMed Central

Melvin Keller, David; Fadel, Paul J; Ogoh, Shigehiko; Matthew Brothers, Robert; Hawkins, Megan; Olivencia-Yurvati, Al; Raven, Peter B

2004-01-01

Carotid baroreflex (CBR) function was examined in five men and three women (25 ± 1 years) using the variable-pressure neck collar technique at rest and during dynamic, one-legged knee extension exercise at 7 W and 25 W. The CBR exhibited control of leg vascular conductance (LVC) at rest and during exercise in both an exercising leg (EL) and a non-exercising leg (NEL) across a wide range of pressures from +40 Torr neck pressure (NP) to −80 Torr neck suction (NS). Specifically, increases in LVC (% change) in response to NS were no different across −20 to −80 Torr in either EL or NEL compared to rest, P > 0.05. However, CBR-mediated decreases in percentage LVC in response to NP were attenuated in EL at both 7 W (16 ± 1%) and 25 W (12 ± 1%) compared to rest (40 ± 3%; P < 0.05) as well as compared to responses in the NEL (36 ± 6% at 7 W and 36 ± 7% at 25 W; P < 0.05). This decrease in vascular responsiveness in EL was associated with a reduction in the gain of the percentage muscle sympathetic nerve activity (%MSNA)–%LVC relationship compared to rest (P < 0.05). Collectively, these data indicate that, despite a clear attenuation of the vascular response to MSNA in the exercising leg, CBR-mediated changes in mean arterial pressure were no different between rest and exercise. PMID:15388778

Association between leg strength and muscle cross-sectional area of the quadriceps femoris with the physical activity level in octogenarians.

PubMed

Latorre-Román, Pedro Á; Arévalo-Arévalo, Juan Manuel; García-Pinillos, Felipe

2016-06-03

Aging is a complex physiological process whose main feature is the progressive loss of functionality, which may be delayed or attenuated by improving physical fitness.  To determine the association between leg strength and the muscle cross-sectional area of the quadriceps femoris in relation to physical activity level in the elderly.  Thirty-two functionally autonomous people over 80 years (men: 82.80±2.09 years; women: 83.77±4.09 years) participated in this study. The Barthel Index, the Yale Physical Activity Survey and the Chair Stand Test were the instruments used.  There were significant differences between sexes in muscle area (p<0.001) in the Chair Stand Test (p=0.028) and the walk index (p=0.029), with higher values in men. The muscle area and the Chair Stand Test correlated significantly with the walk index (r=0.445, p<0.005, and r=0.522, p<0.001, respectively) and the total weekly activity index (r=0.430, p<0.005, and r=0.519, p<0.001, respectively). In the multiple linear regression models for the total weekly activity index, muscle area and the Chair Stand Test, only the latter behaved as a predictor variable.  Muscle strength and muscle mass of quadriceps showed a significant association with the physical activity level in older people. Leg muscle strength was useful to reveal muscle mass and physical activity level in older people, which is relevant as a clinical practice indicator.

Fingertip contact suppresses the destabilizing influence of leg muscle vibration

NASA Technical Reports Server (NTRS)

Lackner, J. R.; Rabin, E.; DiZio, P.

2000-01-01

Touch of the hand with a stationary surface at nonmechanically supportive force levels (<1 N) greatly attenuates postural sway during quiet stance. We predicted such haptic contact would also suppress the postural destabilization caused by vibrating the right peroneus brevis and longus muscles of subjects standing heel-to-toe with eyes closed. In experiment 1, ten subjects were tested under four conditions: no-vibration, no-touch; no-vibration, touch; vibration, no-touch; and vibration, touch. A hand-held physiotherapy vibrator (120 Hz) was applied approximately 5 cm above the malleolous to stimulate the peroneus longus and brevis tendons. Touch conditions involved contact of the right index finger with a laterally positioned surface (<1 N of force) at waist height. Vibration in the absence of finger contact greatly increased the mean sway amplitude of the center of pressure and of the head relative to the no-vibration, no-touch control condition (P < 0.001). The touch, no-vibration and touch-vibration conditions were not significantly different (P > 0.05) from each other and both had significantly less mean sway amplitude of head and of center of pressure than the other conditions (P < 0.01). In experiment 2, eight subjects stood heel-to-toe under touch and no-touch conditions involving 40-s duration trials of peroneus tendon vibration at different duty cycles: 1-, 2-, 3-, and 4-s ON and OFF periods. The vibrator was attached to the subject's leg and remotely activated. In the no-touch conditions, subjects showed periodic postural disruptions contingent on the duty cycle and mirror image rebounds with the offset of vibration. In the touch conditions, subjects were much less disrupted and showed compensations occurring within 500 ms of vibration onset and mirror image rebounds with vibration offset. Subjects were able to suppress almost completely the destabilizing influence of the vibration in the 3- and 4-s duty cycle trials. These experiments show that haptic

Surgery-Induced Changes and Early Recovery of Hip-Muscle Strength, Leg-Press Power, and Functional Performance after Fast-Track Total Hip Arthroplasty: A Prospective Cohort Study

PubMed Central

Holm, Bente; Thorborg, Kristian; Husted, Henrik; Kehlet, Henrik; Bandholm, Thomas

2013-01-01

Background By measuring very early changes in muscle strength and functional performance after fast-track total hip arthroplasty (THA), post-operative rehabilitation, introduced soon after surgery, can be designed to specifically target identified deficits. Objective(s) Firstly, to quantify changes (compared to pre-operative values) in hip muscle strength, leg-press power, and functional performance in the first week after THA, and secondly, to explore relationships between the muscle strength changes, and changes in hip pain, systemic inflammation, and thigh swelling. Design Prospective, cohort study. Setting Convenience sample of patients receiving a THA at Copenhagen University Hospital, Hvidovre, Denmark, between March and December 2011. Participants Thirty-five patients (65.9±7.2 years) undergoing THA. Main outcome measures Hip muscle strength, leg-press power, performance-based function, and self-reported disability were determined prior to, and 2 and 8 days after, THA (Day 2 and 8, respectively). Hip pain, thigh swelling, and C-Reactive Protein were also determined. Results Five patients were lost to follow-up. Hip muscle strength and leg press power were substantially reduced at Day 2 (range of reductions: 41–58%, P<0.001), but less pronounced at Day 8 (range of reductions: 23–31%, P<0.017). Self-reported symptoms and function (HOOS: Pain, Symptoms, and ADL) improved at Day 8 (P<0.014). Changes in hip pain, C-Reactive Protein, and thigh swelling were not related to the muscle strength and power losses. Conclusion(s) Hip muscle strength and leg-press power decreased substantially in the first week after THA – especially at Day 2 – with some recovery at Day 8. The muscle strength loss and power loss were not related to changes in hip pain, systemic inflammation, or thigh swelling. In contrast, self-reported symptoms and function improved. These data on surgery-induced changes in muscle strength may help design impairment-directed, post

Fasciculations in nerve and muscle disorders - A prospective study of muscle ultrasound compared to electromyography.

PubMed

Johansson, M T; Ellegaard, H R; Tankisi, H; Fuglsang-Frederiksen, A; Qerama, E

2017-11-01

We examined the clinical utility of muscle ultrasound (MUS) in detecting fasciculations in patients with nerve and muscle disorders (NMD) and investigated the impact on diagnostic sensitivity when combining electromyography (EMG) and MUS. We included 58 consecutive patients suspected to have NMD and 38 healthy subjects (HS). Patients and HS underwent MUS in 14 skeletal and two bulbar muscles and the video recordings of the MUS were anonymised. Only patients underwent EMG. The follow-up diagnoses were: 15 Amyotrophic lateral sclerosis (ALS), 15 polyneuropathy, 14 patients had other diagnoses (disease-control group) and 14 patients had no pathological findings. MUS detected more muscles with fasciculations among ALS patients compared to all other groups. In ALS patients, the dominating pattern of fasciculations was continuous (45%). More proximal muscles showed fasciculations among ALS patients compared to all other patient groups. MUS was more sensitive than EMG in detecting fasciculations (58% vs. 48%). When combining the two methods, the sensitivity in detecting fasciculations increased to 65%. Fasciculations in nine muscles could predict the ALS diagnosis with high sensitivity and specificity. MUS is a sensitive tool in detecting fasciculations in patients with NMD and performs well compared to EMG in diagnosing ALS. MUS may add valuable information in the clinic, especially in diagnosing ALS. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Discriminant musculo-skeletal leg characteristics between sprint and endurance elite Caucasian runners.

PubMed

Bex, T; Iannaccone, F; Stautemas, J; Baguet, A; De Beule, M; Verhegghe, B; Aerts, P; De Clercq, D; Derave, W

2017-03-01

Excellence in either sprinting or endurance running requires specific musculo-skeletal characteristics of the legs. This study aims to investigate the morphology of the leg of sprinters and endurance runners of Caucasian ethnicity. Eight male sprinters and 11 male endurance runners volunteered to participate in this cross-sectional study. They underwent magnetic resonance imaging and after data collection, digital reconstruction was done to calculate muscle volumes and bone lengths. Sprinters have a higher total upper leg volume compared to endurance runners (7340 vs 6265 cm 3 ). Specifically, the rectus femoris, vastus lateralis, and hamstrings showed significantly higher muscle volumes in the sprint group. For the lower leg, only a higher muscle volume was found in the gastrocnemius lateralis for the sprinters. No differences were found in muscle volume distribution, center of mass in the different muscles, or relative bone lengths. There was a significant positive correlation between ratio hamstrings/quadriceps volume and best running performance in the sprint group. Sprinters and endurance runners of Caucasian ethnicity showed the greatest distinctions in muscle volumes, rather than in muscle distributions or skeletal measures. Sprinters show higher volumes in mainly the proximal and lateral leg muscles than endurance runners. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

ACTN3 R577X polymorphism and explosive leg-muscle power in elite basketball players.

PubMed

Garatachea, Nuria; Verde, Zoraida; Santos-Lozano, Alejandro; Yvert, Thomas; Rodriguez-Romo, Gabriel; Sarasa, Francisco J; Hernández-Sánchez, Sonsoles; Santiago, Catalina; Lucia, Alejandro

2014-03-01

To determine the association of the ACTN3 R577X polymorphism with leg-muscle explosive power in Spanish (white) elite basketball players and controls. 100 (60 men) elite basketball players (cases) and 283 nonathletic controls. The authors assessed power performance by means of the vertical-squat and countermovement-jump tests. Genotype distributions did not differ between groups (cases: 37.0% [RR], 42.0% [RX], and 21.0% [XX]; controls: 31.8% [RR], 49.8% [RX], and 18.4% [XX]; P = .353). The authors did not observe any effect of the ACTN3 R577X polymorphism on study phenotypes in either group, including when they performed the analyses separately in men and women. They found no association between the ACTN3 R577X polymorphism and the likelihood of being an elite basketball player using the dominant or the recessive model, and the results remained unaltered when the analyses were adjusted for sex, weight, height, and age or when performed for men and women separately. Although the ACTN3 R577X is associated with explosive muscle performance and this phenotype is important in the sport of basketball (ie, during jumps), the authors found no association with leg explosive power in elite basket players or with the status of being this type of athlete.

Prophylactic knee bracing alters lower-limb muscle forces during a double-leg drop landing.

PubMed

Ewing, Katie A; Fernandez, Justin W; Begg, Rezaul K; Galea, Mary P; Lee, Peter V S

2016-10-03

Anterior cruciate ligament (ACL) injury can be a painful, debilitating and costly consequence of participating in sporting activities. Prophylactic knee bracing aims to reduce the number and severity of ACL injury, which commonly occurs during landing maneuvers and is more prevalent in female athletes, but a consensus on the effectiveness of prophylactic knee braces has not been established. The lower-limb muscles are believed to play an important role in stabilizing the knee joint. The purpose of this study was to investigate the changes in lower-limb muscle function with prophylactic knee bracing in male and female athletes during landing. Fifteen recreational athletes performed double-leg drop landing tasks from 0.30m and 0.60m with and without a prophylactic knee brace. Motion analysis data were used to create subject-specific musculoskeletal models in OpenSim. Static optimization was performed to calculate the lower-limb muscle forces. A linear mixed model determined that the hamstrings and vasti muscles produced significantly greater flexion and extension torques, respectively, and greater peak muscle forces with bracing. No differences in the timings of peak muscle forces were observed. These findings suggest that prophylactic knee bracing may help to provide stability to the knee joint by increasing the active stiffness of the hamstrings and vasti muscles later in the landing phase rather than by altering the timing of muscle forces. Further studies are necessary to quantify whether prophylactic knee bracing can reduce the load placed on the ACL during intense dynamic movements. Copyright © 2016 Elsevier Ltd. All rights reserved.

Unilateral Muscle Overuse Causes Bilateral Changes in Muscle Fiber Composition and Vascular Supply

PubMed Central

Song, Yafeng; Forsgren, Sture; Liu, Jing-Xia; Yu, Ji-Guo; Stål, Per

2014-01-01

Unilateral strength training can cause cross-transfer strength effects to the homologous contralateral muscles. However, the impact of the cross-over effects on the muscle tissue is unclear. To test the hypothesis that unilateral muscle overuse causes bilateral alterations in muscle fiber composition and vascular supply, we have used an experimental rabbit model with unilateral unloaded overstrain exercise via electrical muscle stimulation (E/EMS). The soleus (SOL) and gastrocnemius (GA) muscles of both exercised (E) and contralateral non-exercised (NE) legs (n = 24) were morphologically analyzed after 1w, 3w and 6w of EMS. Non-exercised rabbits served as controls (n = 6). After unilateral intervention the muscles of both E and NE legs showed myositis and structural and molecular tissue changes that to various degrees mirrored each other. The fiber area was bilaterally smaller than in controls after 3w of E/EMS in both SOL (E 4420 and NE 4333 µm2 vs. 5183 µm2, p<0.05) and GA (E 3572 and NE 2983 µm2 vs. 4697 µm2, p<0.02) muscles. After 6w of E/EMS, the percentage of slow MyHCI fibers was lower than in controls in the NE legs of SOL (88.1% vs. 98.1%, p<0.009), while the percentage of fast MyHCIIa fibers was higher in the NE legs of GA (25.7% vs. 15.8%, p = 0.02). The number of capillaries around fibers in the E and NE legs was lower (SOL 13% and 15%, respectively, GA 25% and 23%, respectively, p<0.05) than in controls. The overall alterations were more marked in the fast GA muscle than in the slow SOL muscle, which on the other hand showed more histopathological muscle changes. We conclude that unilateral repetitive unloaded overuse exercise via EMS causes myositis and muscle changes in fiber type proportions, fiber area and fiber capillarization not only in the exercised leg, but also in the homologous muscles in the non-exercised leg. PMID:25545800

[Acute leg compartment syndrome after exertion].

PubMed

Misović, Sidor; Kronja, Goran; Ignjatović, Dragan; Tomić, Aleksandar

2005-03-01

A case of a 22-year old soldier, with a history of pain in the leg during heavy exercise, which desisted at rest, was presented. One day before admission, the patient had felt an extreme exertion-induced pain in his right leg which had not lessenned at rest. At the same time, the patient noticed persistent severe leg edema. On physical examination, the intracompartmental pressure was 62 mmHg (> 30 mmHg). The patient was urgently operated on, and fasciotomy according to Mubarak was used. At second surgery, the debridement of the muscles of the posterior group of the leg, and the evacuation of hemathoma from the anterior and lateral group of the right leg muscles were perfomed. Postoperative recovery was uneventful. Fasciotomy wounds were closed within 14 days of the surgery. The complete physical treatment was done. Follow-up examinations 1, 3, and 6 months afterwards were satisfactory. The soldier completed his compulsory military service without any sequelae. Laboratory results were normal. Overlooked, unrecognized or surgically untreated compartment syndrome can cause severe damage, including even the loss of the extremity.

Muscle ultrasound elastography and MRI in preschool children with Duchenne muscular dystrophy.

PubMed

Pichiecchio, Anna; Alessandrino, Francesco; Bortolotto, Chandra; Cerica, Alessandra; Rosti, Cristina; Raciti, Maria Vittoria; Rossi, Marta; Berardinelli, Angela; Baranello, Giovanni; Bastianello, Stefano; Calliada, Fabrizio

2018-06-01

The aim of this study was to determine muscle tissue elasticity, measured with shear-wave elastography, in selected lower limb muscles of patients affected by Duchenne muscular dystrophy (DMD) and to correlate the values obtained with those recorded in healthy children and with muscle magnetic resonance imaging (MRI) data from the same DMD children, specifically the pattern on T1-weighted (w) and short-tau inversion recovery (STIR) sequences. Five preschool DMD children and five age-matched healthy children were studied with shear-wave elastography. In the DMD children, muscle stiffness was moderately higher compared with the muscle stiffness in HC, in the rectus femoris, vastus lateralis, adductor magnus and gluteus maximus muscles. On muscle MRI T1-w images showed fatty replacement in 3/5 patients at the level of the GM, while thigh and leg muscles were affected in 2/5; hyperintensity on STIR images was identified in 4/5 patients. No significant correlation was observed between stiffness values and MRI scoring. Our study demonstrated that lower limb muscles of preschool DMD patients show fatty replacement and patchy edema on muscle MRI and increased stiffness on shear-wave elastography. In conclusion, although further studies in larger cohorts are needed, shear-wave elastography could be considered a useful non-invasive tool to easily monitor muscle changes in early stages of the disease. Copyright © 2018 Elsevier B.V. All rights reserved.

Mechanical Impedance of the Non-loaded Lower Leg with Relaxed Muscles in the Transverse Plane

PubMed Central

Ficanha, Evandro Maicon; Ribeiro, Guilherme Aramizo; Rastgaar, Mohammad

2015-01-01

This paper describes the protocols and results of the experiments for the estimation of the mechanical impedance of the humans’ lower leg in the External–Internal direction in the transverse plane under non-load bearing condition and with relaxed muscles. The objectives of the estimation of the lower leg’s mechanical impedance are to facilitate the design of passive and active prostheses with mechanical characteristics similar to the humans’ lower leg, and to define a reference that can be compared to the values from the patients suffering from spasticity. The experiments were performed with 10 unimpaired male subjects using a lower extremity rehabilitation robot (Anklebot, Interactive Motion Technologies, Inc.) capable of applying torque perturbations to the foot. The subjects were in a seated position, and the Anklebot recorded the applied torques and the resulting angular movement of the lower leg. In this configuration, the recorded dynamics are due mainly to the rotations of the ankle’s talocrural and the subtalar joints, and any contribution of the tibiofibular joints and knee joint. The dynamic mechanical impedance of the lower leg was estimated in the frequency domain with an average coherence of 0.92 within the frequency range of 0–30 Hz, showing a linear correlation between the displacement and the torques within this frequency range under the conditions of the experiment. The mean magnitude of the stiffness of the lower leg (the impedance magnitude averaged in the range of 0–1 Hz) was determined as 4.9 ± 0.74 Nm/rad. The direct estimation of the quasi-static stiffness of the lower leg results in the mean value of 5.8 ± 0.81 Nm/rad. An analysis of variance shows that the estimated values for the stiffness from the two experiments are not statistically different. PMID:26697424

Transfection of neurotrophin-3 into neural stem cells using ultrasound with microbubbles to treat denervated muscle atrophy.

PubMed

Gong, Lin; Jiang, Changqing; Liu, Li; Wan, Shengxiang; Tan, Wen; Ma, Sushuang; Jia, Xiaojian; Wang, Meiwei; Hu, Azhen; Shi, Yu; Zhang, Yu; Shen, Yuanyuan; Wang, Feng; Chen, Yun

2018-01-01

Neurotrophin-3 (NT-3) has potential as a therapeutic agent for the treatment of patients with denervated muscle atrophy. However, the endogenous secretion of NT-3 is low and exogenous NT-3 lacks sufficient time to accumulate due to its short half-life. The transfection of NT-3 has been demonstrated to have a beneficial effect on denervated muscle and motor endplates. Neural stem cells (NSCs) differentiate into neurons and form motor endplate nerve-muscle connections. It has been previously demonstrated that local and noninvasive transfection can be performed using ultrasound with microbubbles (MBs). In the current study, hematoxylin and eosin, acetylcholinesterase and gold chloride staining, as well as transmission electron microscopy, were performed to verify the effects of this treatment strategy. The results demonstrated that using ultrasound with MBs for the transfection of NT-3 into NSCs, and their subsequent transplantation in vivo , attenuated the atrophy of denervated muscle and reduced motor endplate degeneration. This noninvasive, efficient and targeted treatment strategy may therefore be a potential treatment for patients with denervated muscle atrophy.

Wavelet decomposition of transmitted ultrasound wave through a 1-D muscle-bone system.

PubMed

Buchanan, James L; Gilbert, Robert P; Ou, Miao-jung Y

2011-01-11

In the attempt for using ultrasound as a diagnostic device for osteoporosis, several authors have described the result of the in vitro experiment in which ultrasound is passed through a cancellous bone specimen placed in a water tank. However, in the in vivo setting, a patient's cancellous bone is surrounded by cortical and muscle layers. This paper considers in the one-dimensional case (1) what effect the cortical bone segments surrounding the cancellous segment would have on the received signal and (2) what the received signal would be when a source and receiver are placed on opposite sides of a structure consisting of a cancellous segment surrounded by cortical and muscle layers. Mathematically this is accomplished by representing the received signal as a sum of wavelets which go through different reflection-transmission histories at the muscle-cortical bone and cortical-cancellous bone interfaces. The muscle and cortical bone are modeled as elastic materials and the cancellous bone as a poroelastic material described by the Biot-Johnson-Koplik-Dashen model. The approach presented here permits the assessment of which possible paths of transmission and reflection through the cortical-cancellous or muscle-cortical-cancellous complex will result in significant contributions to the received waveform. This piece of information can be useful for solving the inverse problem of non-destructive assessment of material properties of bone. Our methodology can be generalized to three-dimensional parallelly layered structure by first applying Fourier transform in the directions perpendicular to the transverse direction. Copyright © 2010 Elsevier Ltd. All rights reserved.

Ultrasound-Guided Removal of an Infected Loose Body from the Quadriceps Muscle.

PubMed

Razdan, Rishi N; Dube, Tiffany; Specht, Neil

2008-01-01

We present the case of a 35 year-old male with pain and swelling in his right thigh. By CT and sonography, an abscess was localized to the deep, anteromedial, mid-thigh within the quadriceps muscle, along with a 1.3 cm loose body. The infected loose body was removed under ultrasound guidance without complications.

Effect of Compression Garments on the Development of Delayed-Onset Muscle Soreness: A Multimodal Approach Using Contrast-Enhanced Ultrasound and Acoustic Radiation Force Impulse Elastography.

PubMed

Heiss, Rafael; Kellermann, Marion; Swoboda, Bernd; Grim, Casper; Lutter, Christoph; May, Matthias S; Wuest, Wolfgang; Uder, Michael; Nagel, Armin M; Hotfiel, Thilo

2018-06-12

Study Design Controlled laboratory study with repeated measures. Background Delayed-onset muscle soreness (DOMS) is one of the most common reasons for impaired muscle performance in sports. However, little consensus exists regarding which treatments may be most effective and the underlying mechanisms are poorly understood. Objectives To investigate the influence of compression garments on the development of DOMS, focusing on changes in muscle perfusion and muscle stiffness. Methods Muscle perfusion and stiffness, calf circumference, muscle soreness, passive ankle dorsiflexion, and creatine kinase levels were assessed on participants before (baseline) a DOMS-inducing eccentric calf exercise intervention and 60 h later (follow-up). After DOMS induction, a sports compression garment (18-21 mmHg) was worn on one randomized calf until follow-up. The contralateral calf served as an internal control. Muscle perfusion was assessed using contrast-enhanced ultrasound (peak enhancement [PE] and wash-in area under the curve [WiAUC]), while muscle stiffness was assessed using acoustic radiation force impulse (shear wave velocities [SWV]). An MRI scan of both lower legs was also performed during the follow-up testing session to characterize the extent of exercise-induced muscle damage. Comparisons were made between limbs and over time. Results SWV values of the medial gastrocnemius showed a significant interaction between time and limb (p=0.006) with the non-compressed muscle demonstrating lower muscle stiffness values at follow-up compared to baseline or the compressed muscle. No significant differences in soleus muscle stiffness were noted between limb or over time, as was the case for muscle perfusion metrics (PE and WiAUC) for the medial gastrocnemius and soleus muscles. Further, compression had no significant effect on passive ankle dorsiflexion, muscle soreness, calf circumference, or injury severity per MRI. Conclusion Continuous wearing of compression garments during the

Relationships between maximal anaerobic power of the arms and legs and javelin performance.

PubMed

Bouhlel, E; Chelly, M S; Tabka, Z; Shephard, R

2007-06-01

The aim of this study was to examine relationships between maximal anaerobic power, as measured by leg and arm force-velocity tests, estimates of local muscle volume and javelin performance. Ten trained national level male javelin throwers (mean age 19.6+/- 2 years) participated in this study. Maximal anaerobic power, maximal force and maximal velocity were measured during leg (Wmax-L) and arm (Wmax-A) force-velocity tests, performed on appropriately modified forms of Monark cycle ergometer. Estimates of leg and arm muscle volume were made using a standard anthropometric kit. Maximal force of the leg (Fmax-L) was significantly correlated with estimated leg muscle volume (r=0.71, P<0.05). Wmax-L and Wmax-A were both significantly correlated with javelin performance (r=0.76, P<0.01; r=0.71, P <0.05, respectively). Maximal velocity of the leg (Vmax-L) was also significantly correlated with throwing performance (r=0.83; P<0.001). Wmax of both legs and arms were significantly correlated with javelin performance, the closest correlation being for Wmax-L; this emphasizes the importance of the leg muscles in this sport. Fmax-L and Vmax-L were related to muscle volume and to javelin performance, respectively. Force-velocity testing may have value in regulating conditioning and rehabilitation in sports involving throwing.

Reliability and Validity of Ultrasound Cross Sectional Area Measurements for Long-Duration Spaceflight

NASA Technical Reports Server (NTRS)

Scott, Jessica M.; Martin, David S.; Cunningham, David; Matz, Timothy; Caine, Timothy; Hackney, Kyle J.; Arzeno, Natalia; Ploutz-Snyder, Lori

2010-01-01

Limb muscle atrophy and the accompanying decline in function can adversely affect the performance of astronauts during mission-related activities and upon re-ambulation in a gravitational environment. Previous characterization of space flight-induced muscle atrophy has been performed using pre and post flight magnetic resonance imaging (MRI). In addition to being costly and time consuming, MRI is an impractical methodology for assessing in-flight changes in muscle size. Given the mobility of ultrasound (US) equipment, it may be more feasible to evaluate changes in muscle size using this technique. PURPOSE: To examine the reliability and validity of using a customized template to acquire panoramic ultrasound (US) images for determining quadriceps and gastrocnemius anatomical cross sectional area (CSA). METHODS: Vastus lateralis (VL), rectus femoris (RF), medial gastrocnemius (MG), and lateral gastrocnemius (LG) CSA were assessed in 10 healthy individuals (36+/-2 yrs) using US and MRI. Panoramic US images were acquired by 2 sonographers using a customized template placed on the thigh and calf and analyzed by the same 2 sonographers (CX50 Philips). MRI images of the leg were acquired while subjects were supine in a 1.5T scanner (Signa Horizon LX, General Electric) and were analyzed by 3 trained investigators. The average of the 2 US and 3 MRI values were used for validity analysis. RESULTS: High inter-experimenter reliability was found for both the US template and MRI analysis as coefficients of variation across muscles ranged from 2.4 to 4.1% and 2.8 to 3.8%, respectively. Significant correlations were found between US and MRI CSA measures (VL, r = 0.85; RF, r = 0.60; MG, r = 0.86; LG, r = 0.73; p < 0.05). Furthermore, the standard error of measurement between US and MRI ranged from 0.91 to 2.09 sq cm with high limits of agreement analyzed by Bland-Altman plots. However, there were significant differences between absolute values of MRI and US for all muscles

EFFECTS OF LOW-FREQUENCY ULTRASOUND ON MICROCIRCULATION IN VENOUS LEG ULCERS

PubMed Central

Wollina, Uwe; Heinig, Birgit; Naumann, Gunther; Scheibe, Armin; Schmidt, Wolf-Dieter; Neugebauer, Reimund

2011-01-01

Background: Therapeutic low-frequency ultrasound (US) has been used for many years to improve wound healing in chronic wounds like venous leg ulcers. No human data are available for the possible effects of single US applications on microcirculation and their frequency-dependency. Aims: To investigated the role of therapeutic low-frequency US on microcirculation of venous leg ulcers in vivo. Patients and Methods: This is a pilot study on an inpatient basis. We use a newly developed low-frequency continuous-wave US-equipment composed of a US transducer based on piezo-fiber composites that allow the change of frequency. In this study, we apply US of 34 kHz, 53.5 kHz, and 75 kHz respectively. Twelve patients with chronic venous leg ulcers are analyzed. As an adjunct to good ulcer care, therapeutic US is applied, non-contacting, once a day, in a subaqual position for 10 minutes. Microcirculation is assessed in the ulcers adjacent to skin before US-therapy, immediately after the treatment and 30 minutes later. We use a micro-light guide spectrophotometer (O2C, LEA Medizintechnik GmbH, Gieίen, Germany) for calculation of blood flow velocity, hemoglobin oxygen saturation (SCO2) and relative hemoglobin concentration (rHb) in 2 and 8 mm depth. Contact-free remission spectroscopy (SkinREM3, Color Control Chemnitz GmbH, Chemnitz, Germany) allows contact free measurements in the VIS-NIR range of the spectrum (400 ± 1600 nm). Results: It is seen that therapeutic US is well tolerated. One patient dropped out from a treatment series since he developed erysipelas responding to standard antibiotic. Effects were seen at 34 kHz only. The SO2 values increased after single US application. The values for rHb were higher in the superficial layer of the wound bed (depth 2 mm) compared to deeper parts (8 mm depth). US treatment did not result in significant changes of rHb and blood cell velocity. The data obtained by remission spectroscopy disclose an increase of oxygenized hemoglobin

Diffusion Properties and 3D Architecture of Human Lower Leg Muscles Assessed with Ultra-High-Field-Strength Diffusion-Tensor MR Imaging and Tractography: Reproducibility and Sensitivity to Sex Difference and Intramuscular Variability.

PubMed

Fouré, Alexandre; Ogier, Augustin C; Le Troter, Arnaud; Vilmen, Christophe; Feiweier, Thorsten; Guye, Maxime; Gondin, Julien; Besson, Pierre; Bendahan, David

2018-05-01

Purpose To demonstrate the reproducibility of the diffusion properties and three-dimensional structural organization measurements of the lower leg muscles by using diffusion-tensor imaging (DTI) assessed with ultra-high-field-strength (7.0-T) magnetic resonance (MR) imaging and tractography of skeletal muscle fibers. On the basis of robust statistical mapping analyses, this study also aimed at determining the sensitivity of the measurements to sex difference and intramuscular variability. Materials and Methods All examinations were performed with ethical review board approval; written informed consent was obtained from all volunteers. Reproducibility of diffusion tensor indexes assessment including eigenvalues, mean diffusivity, and fractional anisotropy (FA) as well as muscle volume and architecture (ie, fiber length and pennation angle) were characterized in lower leg muscles (n = 8). Intramuscular variability and sex differences were characterized in young healthy men and women (n = 10 in each group). Student t test, statistical parametric mapping, correlation coefficients (Spearman rho and Pearson product-moment) and coefficient of variation (CV) were used for statistical data analysis. Results High reproducibility of measurements (mean CV ± standard deviation, 4.6% ± 3.8) was determined in diffusion properties and architectural parameters. Significant sex differences were detected in FA (4.2% in women for the entire lower leg; P = .001) and muscle volume (21.7% in men for the entire lower leg; P = .008), whereas architecture parameters were almost identical across sex. Additional differences were found independently of sex in diffusion properties and architecture along several muscles of the lower leg. Conclusion The high-spatial-resolution DTI assessed with 7.0-T MR imaging allows a reproducible assessment of structural organization of superficial and deep muscles, giving indirect information on muscle function. © RSNA, 2018 Online supplemental material is

A load-based mechanism for inter-leg coordination in insects

PubMed Central

2017-01-01

Animals rely on an adaptive coordination of legs during walking. However, which specific mechanisms underlie coordination during natural locomotion remains largely unknown. One hypothesis is that legs can be coordinated mechanically based on a transfer of body load from one leg to another. To test this hypothesis, we simultaneously recorded leg kinematics, ground reaction forces and muscle activity in freely walking stick insects (Carausius morosus). Based on torque calculations, we show that load sensors (campaniform sensilla) at the proximal leg joints are well suited to encode the unloading of the leg in individual steps. The unloading coincides with a switch from stance to swing muscle activity, consistent with a load reflex promoting the stance-to-swing transition. Moreover, a mechanical simulation reveals that the unloading can be ascribed to the loading of a specific neighbouring leg, making it exploitable for inter-leg coordination. We propose that mechanically mediated load-based coordination is used across insects analogously to mammals. PMID:29187626

Force-velocity property of leg muscles in individuals of different level of physical fitness

PubMed Central

Cuk, Ivan; Mirkov, Dragan; Nedeljkovic, Aleksandar; Kukolj, Milos; Ugarkovic, Dusan; Jaric, Slobodan

2016-01-01

The present study explored the method of testing muscle mechanical properties through the linear force-velocity (F–V) relationships obtained from loaded vertical jumps. Specifically, we hypothesised that the F-V relationship parameters depicting the force, power, and velocity of the tested muscles will differ among individuals of different physical fitness. Strength trained, physically active, and sedentary male participants (N=10+10+10; age 20–29 years) were tested on maximum countermovement and squat jumps where manipulation of external loads provided a range of F and V data. The observed F–V relationships of the tested leg muscles were approximately linear and mainly strong (median correlation coefficients ranged from 0.77 to 0.92; all p < 0.05), independently of either the tested group or the jump type. The maximum power revealed higher values in the strength trained than in the physically active and sedentary participants. This difference originated from the differences in F-intercepts, rather than from the V-intercepts. We conclude that the observed parameters could be sensitive enough to detect the differences among both the individuals of different physical fitness and various jump types. The present findings support using loaded vertical jumps and, possibly, other maximum performance multi-joint movements for the assessment of mechanical properties of active muscles. PMID:27111493

Are the hamstrings from the drive leg or landing leg more active in baseball pitchers? An electromyographic study.

PubMed

Erickson, Brandon J; Zaferiou, Antonia; Chalmers, Peter N; Ruby, Deana; Malloy, Phillip; Luchetti, Timothy J; Verma, Nikhil N; Romeo, Anthony A

2017-11-01

Ulnar collateral ligament reconstruction (UCLR) has become a common procedure among baseball players of all levels. There are several graft choices in performing UCLR, one of which is a hamstring (gracilis or semitendinosus) autograft. It is unclear whether the hamstring muscle from a pitcher's drive leg (ipsilateral side of the UCLR) or landing leg (contralateral side of the UCLR) is more active during the pitching motion. We hypothesized that the landing leg semitendinosus will be more electromyographically active than the drive leg. Healthy, elite male pitchers aged 16-21 years were recruited. Sixteen pitchers (average age, 17.6 ± 1.6 years; 67% threw right handed) underwent electromyographic analysis. Pitchers threw 5 fastballs at 100% effort from the wind-up with electromyographic analysis of every pitch. Activation of the semitendinosus and biceps femoris in both legs was compared within pitchers and between pitchers. Hamstring activity was higher in the drive leg than in the landing leg during each phase and in sum, although the difference was significant only during the double support phase (P = .021). On within-pitcher analysis, 10 of 16 pitchers had significantly more sum hamstring activity in the drive leg than in the landing leg, while only 4 of 16 had more activity in the landing leg (P = .043). During the baseball pitch, muscle activity of the semitendinosus was higher in the drive leg than in the landing leg in most pitchers. Surgeons performing UCLR using hamstring autograft should consider harvesting the graft from the pitcher's landing leg to minimize disruption to the athlete's pitching motion. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Measurement of anterior tibial muscle size using real-time ultrasound imaging.

PubMed

Martinson, H; Stokes, M J

1991-01-01

Cross-sectional images of the anterior tibial muscle group were obtained using real-time ultrasound scanning in 17 normal women. From photographs taken of the images, the cross-sectional area (CSA) and two linear measurements of muscle cross-section were determined. A measurement of the shortest distance of the muscle depth was termed DS, and a measurement of the longest distance through the muscle group was termed DL. Both linear dimensions showed a positive correlation with CSA and the best correlations were obtained when the dimensions were squared or combined (DS x DL). The correlation values were: CSA vs DS2, r = 0.9; CSA vs DL2, r = 0.75 and CSA vs DS x DL, r = 0.88. An approximate value for CSA could be calculated from DS2 by the equation 2 x DS2 + 1. A shape ratio, obtained by dividing DL by DS, was consistent within the group [mean 2.1 (SD 0.2)] and characterised the muscle geometrically. The CSA of repeated scans was assessed for repeatability between-days and between-scans by analysis of variance and the coefficient of variation (CV) calculated. Areas were repeatable between-days (CV 6.5%) and between-scans (CV 3.6%). Linear dimensions of the anterior tibial muscle group reflected CSA and their potential for assessing changes in muscle size with atrophy and hypertrophy have yet to be established.

Ultrasound Evaluation of the Abdominal Wall and Lumbar Multifidus Muscles in Participants Who Practice Pilates: A 1-year Follow-up Case Series.

PubMed

Gala-Alarcón, Paula; Calvo-Lobo, César; Serrano-Imedio, Ana; Garrido-Marín, Alejandro; Martín-Casas, Patricia; Plaza-Manzano, Gustavo

2018-04-18

The purpose of this study was to describe ultrasound (US) changes in muscle thickness produced during automatic activation of the transversus abdominis (TrAb), internal oblique (IO), external oblique (EO), and rectus abdominis (RA), as well as the cross-sectional area (CSA) of the lumbar multifidus (LM), after 1 year of Pilates practice. A 1-year follow-up case series study with a convenience sample of 17 participants was performed. Indeed, TrAb, IO, EO, and RA thickness, as well as LM CSA changes during automatic tests were measured by US scanning before and after 1 year of Pilates practice twice per week. Furthermore, quality of life changes using the 36-Item Short Form Health Survey and US measurement comparisons of participants who practiced exercises other than Pilates were described. Statistically significant changes were observed for the RA muscle thickness reduction during the active straight leg raise test (P = .007). Participants who practiced other exercises presented a larger LM CSA and IO thickness, which was statistically significant (P < .05). Statistically significant changes were not observed for the domains of the analyzed 36-Item Short Form Health Survey (P > .05). A direct moderate correlation was observed (r = 0.562, P = .019) between the TrAb thickness before and after a 1-year follow-up. Long-term Pilates practice may reduce the RA thickness automatic activation during active straight leg raise. Furthermore, LM CSA and IO thickness increases were observed in participants who practice other exercise types in conjunction with Pilates. Despite a moderate positive correlation observed for TrAb thickness, the quality of life did not seem to be modified after long-term Pilates practice. Copyright © 2018. Published by Elsevier Inc.

Leg Muscle Involvement in Facioscapulohumeral Muscular Dystrophy: Comparison between Facioscapulohumeral Muscular Dystrophy Types 1 and 2.

PubMed

Mair, Dorothea; Huegens-Penzel, Monika; Kress, Wolfram; Roth, Christian; Ferbert, Andreas

2017-01-01

Facioscapulohumeral muscular dystrophy (FSHD) presents with 2 genetically distinct types. We describe for the first time the MRI patterns of leg muscle involvement in type 2 and compare it with type 1. The intramuscular fat content was assessed on lower extremity axial T1-weighted MRI scans in 6 FSHD1 and 5 FSHD2 patients. Overall, the muscle involvement profile did not differ substantially between FSHD1 and FSHD2. In the thigh, the dorsomedial compartment including the semimembranosus, semitendinosus and adductor magnus was the most affected. The quadriceps was mostly spared, but isolated involvement of the rectus femoris was common. Fat infiltration in the distal soleus and the medial gastrocnemius with sparing of the lateral gastrocnemius was a common finding; involvement of the tibialis anterior was less frequent. A proximal-to-distal increase in fat content was frequently present in some muscles. Muscle involvement appears to be independent of type, confirming a similar pathophysiological pathway in FSHD1 and FSHD2. © 2016 S. Karger AG, Basel.

Muscle thickness measurements of the lower trapezius with rehabilitative ultrasound imaging are confounded by scapular dyskinesis.

PubMed

Seitz, Amee L; Baxter, Caralyn J; Benya, Kristen

2015-08-01

Alterations in scapular muscle activity have been theorized to contribute to abnormal scapular motion and shoulder pain, but pose challenges to quantify in the clinic. Rehabilitative Ultrasound Imaging (RUSI) has proved useful identifying dysfunction of lumbar regional stabilizing muscle activity, specifically contractile behavior. Although, recent examinations of scapular stabilizing trapezius muscle function using RUSI did not detect alterations individuals with shoulder pain or differences in muscle thickness between varying external loads in asymptomatic individuals, a potential confounder to prior results, scapular dyskinesis has not been controlled. It is unknown if dyskinesis alters scapular muscle thickness during activation measured with RUSI. Thus, the purpose of this study was to compare change in scapular muscle thickness between individuals with and without scapular dyskinesis. Thirty-nine asymptomatic adults with (n = 19) and without (n = 20) scapular dyskinesis, defined with a reliable and validated method, participated. Two separate ultrasound images of the serratus anterior (SA) and lower trapezius (LT) were captured under two randomized conditions, rest and isometric contraction against gravity, and saved for blinded measurement. Change in thickness with contraction was calculated and expressed as a percentage. The dyskinesis group demonstrated a greater increase (p = 0.005) in LT thickness with the isometric contraction than the group without (mean difference = 31.6%; 95%CI = 10.3, 53.0). No differences in SA or resting thickness of either muscle were found between groups. The presence of scapular dyskinesis alters thickness changes of the lower trapezius during activation. Furthermore, potential underlying reasons beyond muscle contractile behavior must be considered. Copyright © 2015 Elsevier Ltd. All rights reserved.

Automated diagnosis of myositis from muscle ultrasound: Exploring the use of machine learning and deep learning methods

PubMed Central

Burlina, Philippe; Billings, Seth; Joshi, Neil

2017-01-01

Objective To evaluate the use of ultrasound coupled with machine learning (ML) and deep learning (DL) techniques for automated or semi-automated classification of myositis. Methods Eighty subjects comprised of 19 with inclusion body myositis (IBM), 14 with polymyositis (PM), 14 with dermatomyositis (DM), and 33 normal (N) subjects were included in this study, where 3214 muscle ultrasound images of 7 muscles (observed bilaterally) were acquired. We considered three problems of classification including (A) normal vs. affected (DM, PM, IBM); (B) normal vs. IBM patients; and (C) IBM vs. other types of myositis (DM or PM). We studied the use of an automated DL method using deep convolutional neural networks (DL-DCNNs) for diagnostic classification and compared it with a semi-automated conventional ML method based on random forests (ML-RF) and “engineered” features. We used the known clinical diagnosis as the gold standard for evaluating performance of muscle classification. Results The performance of the DL-DCNN method resulted in accuracies ± standard deviation of 76.2% ± 3.1% for problem (A), 86.6% ± 2.4% for (B) and 74.8% ± 3.9% for (C), while the ML-RF method led to accuracies of 72.3% ± 3.3% for problem (A), 84.3% ± 2.3% for (B) and 68.9% ± 2.5% for (C). Conclusions This study demonstrates the application of machine learning methods for automatically or semi-automatically classifying inflammatory muscle disease using muscle ultrasound. Compared to the conventional random forest machine learning method used here, which has the drawback of requiring manual delineation of muscle/fat boundaries, DCNN-based classification by and large improved the accuracies in all classification problems while providing a fully automated approach to classification. PMID:28854220

Automated diagnosis of myositis from muscle ultrasound: Exploring the use of machine learning and deep learning methods.

PubMed

Burlina, Philippe; Billings, Seth; Joshi, Neil; Albayda, Jemima

2017-01-01

To evaluate the use of ultrasound coupled with machine learning (ML) and deep learning (DL) techniques for automated or semi-automated classification of myositis. Eighty subjects comprised of 19 with inclusion body myositis (IBM), 14 with polymyositis (PM), 14 with dermatomyositis (DM), and 33 normal (N) subjects were included in this study, where 3214 muscle ultrasound images of 7 muscles (observed bilaterally) were acquired. We considered three problems of classification including (A) normal vs. affected (DM, PM, IBM); (B) normal vs. IBM patients; and (C) IBM vs. other types of myositis (DM or PM). We studied the use of an automated DL method using deep convolutional neural networks (DL-DCNNs) for diagnostic classification and compared it with a semi-automated conventional ML method based on random forests (ML-RF) and "engineered" features. We used the known clinical diagnosis as the gold standard for evaluating performance of muscle classification. The performance of the DL-DCNN method resulted in accuracies ± standard deviation of 76.2% ± 3.1% for problem (A), 86.6% ± 2.4% for (B) and 74.8% ± 3.9% for (C), while the ML-RF method led to accuracies of 72.3% ± 3.3% for problem (A), 84.3% ± 2.3% for (B) and 68.9% ± 2.5% for (C). This study demonstrates the application of machine learning methods for automatically or semi-automatically classifying inflammatory muscle disease using muscle ultrasound. Compared to the conventional random forest machine learning method used here, which has the drawback of requiring manual delineation of muscle/fat boundaries, DCNN-based classification by and large improved the accuracies in all classification problems while providing a fully automated approach to classification.

Neural effects of muscle stretching on the spinal reflexes in multiple lower-limb muscles.

PubMed

Masugi, Yohei; Obata, Hiroki; Inoue, Daisuke; Kawashima, Noritaka; Nakazawa, Kimitaka

2017-01-01

While previous studies have shown that muscle stretching suppresses monosynaptic spinal reflex excitability in stretched muscles, its effects on non-stretched muscles is still largely unknown. The purpose of this study was to examine the effects of muscle stretching on monosynaptic spinal reflex in non-stretched muscles. Ten healthy male subjects participated in this study. Muscle stretching of the right triceps surae muscle was performed using a motor torque device for 1 minute. Three different dorsiflexion torques (at approximately 5, 10, and 15 Nm) were applied during muscle stretching. Spinal reflexes evoked by transcutaneous spinal cord stimulation were recorded in both the lower-limb muscles before, during, and at 0 and 5 min following muscle stretching. The amplitudes of the spinal reflexes in both the stretched and non-stretched muscles in the right (ipsilateral) leg were smaller during stretching compared to before, and at 0 and 5 min after stretching. Furthermore, the degree of reduction in the amplitude of the spinal reflexes in the right (ipsilateral) leg muscles increased significantly as the dorsiflexion torque (i.e., stretching of the right triceps surae muscles) increased. In contrast, reduction in the amplitude of the spinal reflexes with increasing dorsiflexion torque was not seen in the left (contralateral) leg muscles. Our results clearly indicate that muscle stretching has inhibitory effects on monosynaptic spinal reflexes, not only in stretched muscles, but also in non-stretched muscles of the ipsilateral leg.

Neural effects of muscle stretching on the spinal reflexes in multiple lower-limb muscles

PubMed Central

Obata, Hiroki; Inoue, Daisuke; Kawashima, Noritaka; Nakazawa, Kimitaka

2017-01-01

While previous studies have shown that muscle stretching suppresses monosynaptic spinal reflex excitability in stretched muscles, its effects on non-stretched muscles is still largely unknown. The purpose of this study was to examine the effects of muscle stretching on monosynaptic spinal reflex in non-stretched muscles. Ten healthy male subjects participated in this study. Muscle stretching of the right triceps surae muscle was performed using a motor torque device for 1 minute. Three different dorsiflexion torques (at approximately 5, 10, and 15 Nm) were applied during muscle stretching. Spinal reflexes evoked by transcutaneous spinal cord stimulation were recorded in both the lower-limb muscles before, during, and at 0 and 5 min following muscle stretching. The amplitudes of the spinal reflexes in both the stretched and non-stretched muscles in the right (ipsilateral) leg were smaller during stretching compared to before, and at 0 and 5 min after stretching. Furthermore, the degree of reduction in the amplitude of the spinal reflexes in the right (ipsilateral) leg muscles increased significantly as the dorsiflexion torque (i.e., stretching of the right triceps surae muscles) increased. In contrast, reduction in the amplitude of the spinal reflexes with increasing dorsiflexion torque was not seen in the left (contralateral) leg muscles. Our results clearly indicate that muscle stretching has inhibitory effects on monosynaptic spinal reflexes, not only in stretched muscles, but also in non-stretched muscles of the ipsilateral leg. PMID:28662201

H:q ratios and bilateral leg strength in college field and court sports players.

PubMed

Cheung, Roy T H; Smith, Andrew W; Wong, Del P

2012-06-01

One of the key components in sports injury prevention is the identification of imbalances in leg muscle strength. However, different leg muscle characteristics may occur in large playing area (field) sports and small playing area (court) sports, which should be considered in regular injury prevention assessment. This study examined the isokinetic hamstrings-to-quadriceps (H:Q) ratio and bilateral leg strength balance in 40 male college (age: 23.4 ± 2.5 yrs) team sport players (field sport = 23, soccer players; court sport = 17, volleyball and basketball players). Five repetitions of maximal knee concentric flexion and concentric extension were performed on an isokinetic dynamometer at two speeds (slow: 60°·s(-1) and fast: 300°·s(-1)) with 3 minutes rest between tests. Both legs were measured in counterbalanced order with the dominant leg being determined as the leg used to kick a ball. The highest concentric peak torque values (Nm) of the hamstrings and quadriceps of each leg were analyzed after body mass normalization (Nm·kg(-1)). Court sport players showed significantly weaker dominant leg hamstrings muscles at both contraction speeds (P < 0.05). The H:Q ratio was significantly larger in field players in their dominant leg at 60°·s(-1) (P < 0.001), and their non-dominant leg at 300°·s(-1) (P < 0.001) respectively. Sport-specific leg muscle strength was evident in college players from field and court sports. These results suggest the need for different muscle strength training and rehabilitation protocols for college players according to the musculature requirements in their respective sports.

[Effect of vibratory stimulation of foot support areas in rats on the functional state of leg muscles and the content of N2A titin isoforms in gravity relief].

PubMed

Baltina, Y V; Kuznetsov, M V; Yeremeev, A A; Baltin, M E

2014-01-01

In this work, we studied the effect of vibratory stimulation of the foot support zones on the functional state of the leg muscles and the content of N2A titin isoforms in rats under simulated microgravity (hanging model). The results of this study showed that vibratory support zones of the rat foot in a gravity discharge may reduce the incidence in amplitude of the leg muscle motor response and undesirable reduction of the titin content.

Effects of high intensity ultrasound treatment, storage time and cooking method on shear, sensory, instrumental color and cooking properties of packaged and unpackaged beef pectoralis muscle.

PubMed

Pohlman, F W; Dikeman, M E; Kropf, D H

1997-05-01

Beef pectoralis muscles were removed at 24 h post mortem from nine steers, and samples were vacuum packaged and exposed to high-intensity ultrasound (20 kHz, 22 W/cm(2)) for 0, 5 or 10 min, then aged for 1, 6 or 10 days before evaluation of purge and cooking losses, instrumental shear and color and sensory traits (Experiment 1). For Experiment 2, unpackaged beef pectoralis muscle samples from eight steers were subjected to ultrasonic cooking, boiling, convection cooking or ultrasound treatment for 5 or 10 min followed by cooking in a convection oven. Neither duration of sonication nor storage of packaged pectoralis muscles affected (p > 0.05) storage purge or cooking losses, shear properties or sensory characteristics (Experiment 1). However, muscles receiving ultrasonic treatment showed tendencies for reduced peak force and total work to shear. Increased length of storage caused pectoralis muscles to become more vivid red-orange colored (p < 0.05), whereas ultrasonic treatment caused muscles to become less vivid, less red and more orange colored (p < 0.05). Ultrasonically cooked pectoralis muscles (Experiment 2) had lower (p < 0.05) cooking losses than muscles cooked by other methods. Both ultrasonic cooking and boiling were faster than convection cooking only and ultrasound exposure followed by convection cooking. Additional studies are needed to verify the ability of ultrasound to promote improved cooking, sensory and shear properties of muscle.

Ultrasound Imaging System Video

NASA Technical Reports Server (NTRS)

2002-01-01

In this video, astronaut Peggy Whitson uses the Human Research Facility (HRF) Ultrasound Imaging System in the Destiny Laboratory of the International Space Station (ISS) to image her own heart. The Ultrasound Imaging System provides three-dimension image enlargement of the heart and other organs, muscles, and blood vessels. It is capable of high resolution imaging in a wide range of applications, both research and diagnostic, such as Echocardiography (ultrasound of the heart), abdominal, vascular, gynecological, muscle, tendon, and transcranial ultrasound.

Intrarater and interrater reliability of assessment of lumbar multifidus muscle thickness using rehabilitative ultrasound imaging.

PubMed

Wallwork, Tracy L; Hides, Julie A; Stanton, Warren R

2007-10-01

Within-session intrarater and interrater reliability study. To establish the intrarater and interrater reliability of thickness measurements of the multifidus muscle in a parasagittal plane, conducted by an experienced ultrasound operator and a novice assessor. There is considerable evidence for the important role of the multifidus muscle in segmental stabilization of the lumbar spine. The cross-sectional area of the multifidus muscle has been assessed in healthy subjects and patients with low back pain using real-time ultrasound imaging. However, few studies have measured the thickness of the multifidus muscle using a parasagittal view. The thickness of the multifidus muscle was measured at rest, using real-time ultrasound imaging, in 10 subjects without a history of low back pain, at the levels of the L2-3 and L4-5 zygapophyseal joints. The measure was carried out 3 times at each level by 2 assessors (1 experienced, 1 novice). Intrarater (model 3) and interrater (model 2) reliability was assessed by calculation of an F statistic (analysis of variance), the intraclass correlation coefficient (ICC), and the standard error of measurement (SEM). On the basis of an average of 3 trials, the 2 operators showed very high interrater agreement on the measurement of thicknesses at the L2-3 level (ICC2,3 = 0.96; 95% CI: 0.84 to 0.99) and the L4-5 vertebral level (ICC2,3 = 0.97; 95% CI: 0.87 to 0.99), with no systematic differences in muscle size across operators (P > .05). Interrater reliability was relatively lower for the L2-3 level (ICC2,1 = 0.85; 95% CI: 0.51 to 0.96) than the L4-5 level (ICC2,1 = 0.87; 95% CI: 0.52 to 0.97) when a single trial per rater was used, but these values still indicated a high level of agreement. In addition, the novice and experienced operator produced reliable intrarater measurements at L2-3 (ICC3,1 = 0.89; 95% CI: 0.72 to 0.97 and 0.94; 95% CI: 0.86 to 0.99) and at L4-5 (ICC3,1 = 0.88; 95% CI: 0.68 to 0.97 and 0.95; 95% CI: 0.86 to 0

[Ultrasound findings in rhabdomyolysis].

PubMed

Carrillo-Esper, Raúl; Galván-Talamantes, Yazmin; Meza-Ayala, Cynthia Margarita; Cruz-Santana, Julio Alberto; Bonilla-Reséndiz, Luis Ignacio

Rhabdomyolysis is defined as skeletal muscle necrosis. Ultrasound assessment has recently become a useful tool for the diagnosis and monitoring of muscle diseases, including rhabdomyolysis. A case is presented on the ultrasound findings in a patient with rhabdomyolysis. To highlight the importance of ultrasound as an essential part in the diagnosis in rhabdomyolysis, to describe the ultrasound findings, and review the literature. A 30 year-old with post-traumatic rhabdomyolysis of both thighs. Ultrasound was performed using a Philips Sparq model with a high-frequency linear transducer (5-10MHz), in low-dimensional scanning mode (2D), in longitudinal and transverse sections at the level of both thighs. The images obtained showed disorganisation of the orientation of the muscle fibres, ground glass image, thickening of the muscular fascia, and the presence of anechoic areas. Ultrasound is a useful tool in the evaluation of rhabdomyolysis. Copyright © 2015 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

Leg lengthening and shortening

MedlinePlus

... to match its length. Proper timing of this treatment is important for best results. Certain health conditions can lead to very unequal leg lengths. They include: Poliomyelitis Cerebral palsy Small, weak muscles or short, tight ( ...

Force-velocity property of leg muscles in individuals of different level of physical fitness.

PubMed

Cuk, Ivan; Mirkov, Dragan; Nedeljkovic, Aleksandar; Kukolj, Milos; Ugarkovic, Dusan; Jaric, Slobodan

2016-06-01

The present study explored the method of testing muscle mechanical properties through the linear force-velocity (F-V) relationships obtained from loaded vertical jumps. Specifically, we hypothesised that the F-V relationship parameters depicting the force, power, and velocity of the tested muscles will differ among individuals of different physical fitness. Strength trained, physically active, and sedentary male participants (N = 10 + 10 + 10; age 20-29 years) were tested on maximum countermovement and squat jumps where manipulation of external loads provided a range of F and V data. The observed F-V relationships of the tested leg muscles were approximately linear and mainly strong (median correlation coefficients ranged from 0.77 to 0.92; all p < 0.05), independently of either the tested group or the jump type. The maximum power revealed higher values in the strength trained than in the physically active and sedentary participants. This difference originated from the differences in F-intercepts, rather than from the V-intercepts. We conclude that the observed parameters could be sensitive enough to detect the differences among both the individuals of different physical fitness and various jump types. The present findings support using loaded vertical jumps and, possibly, other maximum performance multi-joint movements for the assessment of mechanical properties of active muscles.

Evaluating the influence of massage on leg strength, swelling, and pain following a half-marathon.

PubMed

Dawson, Lance G; Dawson, Kimberley A; Tiidus, Peter M

2004-11-01

Massage therapy is commonly used following endurance running races with the expectation that it will enhance post-run recovery of muscle function and reduce soreness. A limited number of studies have reported little or no influence of massage therapy on post-exercise muscle recovery. However, no studies have been conducted in a field setting to assess the potential for massage to influence muscle recovery following an actual endurance running race. To evaluate the potential for repeated massage therapy interventions to influence recovery of quadriceps and hamstring muscle soreness, recovery of quadriceps and hamstring muscle strength and reduction of upper leg muscle swelling over a two week recovery period following an actual road running race. Twelve adult recreational runners (8 male, 4 female) completed a half marathon (21.1 km) road race. On days 1,4, 8, and 11 post-race, subjects received 30 minutes of standardized massage therapy performed by a registered massage therapist on a randomly assigned massage treatment leg, while the other (control) leg received no massage treatment. Two days prior to the race (baseline) and preceding the treatments on post-race days 1, 4, 8, and 11 the following measures were conducted on each of the massage and control legs: strength of quadriceps and hamstring muscles, leg swelling, and soreness perception. At day 1, post-race quadriceps peak torque was significantly reduced (p < 0.05), and soreness and leg circumference significantly elevated (p < 0.05) relative to pre-race values with no difference between legs. This suggested that exercise-induced muscle disruption did occur. Comparing the rate of return to baseline measures between the massaged and control legs, revealed no significant differences (p > 0.05). All measures had returned to baseline at day 11. Massage did not affect the recovery of muscles in terms of physiological measures of strength, swelling, or soreness. However, questionnaires revealed that 7 of the 12

Towards a Comparative Measure of Legged Agility

DTIC Science & Technology

2014-06-01

body movement with change of velocity or direction in response to a stimulus” [18]. Notwithstanding the many informative and inspiring studies of legged...specific power (watts per kilogram taken over a gait cycle of leg power output relative to leg muscle mass or body mass) [22, 26–28] but it is not scale...closest to the body mass normalized mea- sure we will introduce below. In contrast, characterizing directional aspects of agility performance seems

UltraTrack: Software for semi-automated tracking of muscle fascicles in sequences of B-mode ultrasound images.

PubMed

Farris, Dominic James; Lichtwark, Glen A

2016-05-01

Dynamic measurements of human muscle fascicle length from sequences of B-mode ultrasound images have become increasingly prevalent in biomedical research. Manual digitisation of these images is time consuming and algorithms for automating the process have been developed. Here we present a freely available software implementation of a previously validated algorithm for semi-automated tracking of muscle fascicle length in dynamic ultrasound image recordings, "UltraTrack". UltraTrack implements an affine extension to an optic flow algorithm to track movement of the muscle fascicle end-points throughout dynamically recorded sequences of images. The underlying algorithm has been previously described and its reliability tested, but here we present the software implementation with features for: tracking multiple fascicles in multiple muscles simultaneously; correcting temporal drift in measurements; manually adjusting tracking results; saving and re-loading of tracking results and loading a range of file formats. Two example runs of the software are presented detailing the tracking of fascicles from several lower limb muscles during a squatting and walking activity. We have presented a software implementation of a validated fascicle-tracking algorithm and made the source code and standalone versions freely available for download. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

On the relationship between lower extremity muscles activation and peak vertical and posterior ground reaction forces during single leg drop landing.

PubMed

Mahaki, M; Mi'mar, R; Mahaki, B

2015-10-01

Anterior cruciate ligament (ACL) injury continues to be an important medical issue for athletes participating in sports. Vertical and posterior ground reaction forces have received considerable attention for their potential influence on ACL injuries. The purpose of this study was to examine the relationship between electromyographic activity of lower extremity muscles and the peak vertical and posterior ground reaction forces during single leg drop landing. Thirteen physical education male students participated in this correlation study. Electromyographic activities of gluteus medius, biceps femoris, medial gastrocnemius, soleus as well as anterior tibialis muscles along with ground reaction forces were measured. Participants performed single-leg landing from a 0.3 m height on to a force platform. Landing was divided into two phases: 100 ms preceding ground contact and 100 ms proceeding ground contact. Pearson correlation test was used to determine the relationships between these muscles activity and peak vertical and posterior ground reaction forces. The results of the study indicated that the activity of soleus and tibialis anterior in pre-landing phase were positively correlated with peak vertical ground reaction force ([P≤0.04], [P≤0.008], respectively). However, no significant correlation was found between the activities of other muscles in pre-landing phase and peak vertical as well as peak posterior ground reaction forces. Also, no significant correlation was found between the activities of muscles in post-landing phase and peak vertical as well as peak posterior ground reaction forces. Soleus loading shifts the proximal tibia posterior at the knee joint and tibialis anterior prevent hyperporonation of the ankle, a mechanisms of ACL injury. Hence, neuromuscular training promoting preparatory muscle activity in these muscles may reduce the incidence of ACL injuries.

The effect of core stability and general exercise on abdominal muscle thickness in non-specific chronic low back pain using ultrasound imaging.

PubMed

Shamsi, MohammadBagher; Sarrafzadeh, Javad; Jamshidi, Aliashraf; Zarabi, Vida; Pourahmadi, Mohammad Reza

2016-05-01

There is a controversy regarding whether core stability exercise (CSE) is more effective than general exercise (GE) for chronic LBP. To compare different exercises regarding their effect on improving back strength and stability, performance of abdominal muscles is a useful index. Ultrasound imaging for measuring muscle thickness could be used to assess muscle performance. The aim of this study was to compare CSE and GE in chronic LBP using ultrasound imaging for measurement of thickness of the deep stabilizing and main global trunk muscles in non-specific chronic LBP. Each program included 16 training sessions three times a week. Using ultrasound imaging, four transabdominal muscle thickness were measured before and after the intervention. Disability and pain were measured as secondary outcomes. After the intervention on participants (n = 43), a significant increase in muscle thickness (hypertrophy) was seen only in right and left rectus abdominis in the GE group, but significant difference to the CSE group was only on the right side. Disability and pain reduced within the groups without a significant difference in the change between them. The present results provided evidence that only GE increased right and left rectus muscle thickness. The only significant difference between CSE and GE groups was the right rectus thickness. As rectus is a global muscle, the effect of GE on strength improvement (one side stronger than the other) may have a negative effect on motor control of lumbopelvic muscles and possibly increase the risk of back pain occurring or becoming worse, though this was not observed in the present study.

[The Activation of Interlimb Interactions Increase the Motor Output in Legs in Healthy Subjects under the Conditions of Arm and Leg Unloading].

PubMed

Selionov, V A; Solopova, I A; Zhvansky, D S

2016-01-01

We studied the effect of arm movements and movements of separate arm joints on the electrophysiological and kinematic characteristics of voluntary and vibration-triggered stepping-like leg movements under the conditions of horizontal support of upper and lower limbs. The horizontal support of arms provided a significantly increase in the rate of activation of locomotor automatism by non-invasive impact on tonic sensory inputs. The addition of active arm movements during involuntary rhytmic stepping-like leg movements led to an increase in EMG activity of hip muscles and was accompanied by an increase in the amplitude of hip and shin movements. Passive arm movements had the same effect on induced leg movements. The movement of the shoulder joints led to an increase in the activity of hip muscles and an increase in the amplitude of movements of the knee and hip joints. At the same time, the movement of forearms. and wrists had similar facilitating effect on electrophysiological and kinematic characteristics of rhytmic stepping-like movements, but influenced the distal segments of legs to a greater extent. Under the conditions of sub-threshold vibration of leg muscles, voluntary arm movements led to the activation of involuntary rhytmic stepping movements. During voluntary leg movements, the addition of arm movements had a significantly smaller impact on the parameters of rhytmic stepping than during involuntary leg movements. Thus, the simultaneous movements of upper and lower limbs are an effective method of activation of neural networks connecting the rhythm generators of arms and legs. Under the conditions of arm and leg unloading, the interactions between the cervical and lumbosacral segments of the spinal cord seem to play the major role in the impact of arm movements on the patterns of leg movements. The described methods of activation of interlimb interactions can be used in the rehabilitation of post-stroke patients and patients with spinal cord injuries

Automated regional analysis of B-mode ultrasound images of skeletal muscle movement

PubMed Central

Darby, John; Costen, Nicholas; Loram, Ian D.

2012-01-01

To understand the functional significance of skeletal muscle anatomy, a method of quantifying local shape changes in different tissue structures during dynamic tasks is required. Taking advantage of the good spatial and temporal resolution of B-mode ultrasound imaging, we describe a method of automatically segmenting images into fascicle and aponeurosis regions and tracking movement of features, independently, in localized portions of each tissue. Ultrasound images (25 Hz) of the medial gastrocnemius muscle were collected from eight participants during ankle joint rotation (2° and 20°), isometric contractions (1, 5, and 50 Nm), and deep knee bends. A Kanade-Lucas-Tomasi feature tracker was used to identify and track any distinctive and persistent features within the image sequences. A velocity field representation of local movement was then found and subdivided between fascicle and aponeurosis regions using segmentations from a multiresolution active shape model (ASM). Movement in each region was quantified by interpolating the effect of the fields on a set of probes. ASM segmentation results were compared with hand-labeled data, while aponeurosis and fascicle movement were compared with results from a previously documented cross-correlation approach. ASM provided good image segmentations (<1 mm average error), with fully automatic initialization possible in sequences from seven participants. Feature tracking provided similar length change results to the cross-correlation approach for small movements, while outperforming it in larger movements. The proposed method provides the potential to distinguish between active and passive changes in muscle shape and model strain distributions during different movements/conditions and quantify nonhomogeneous strain along aponeuroses. PMID:22033532

Muscle Damage and Its Relationship with Muscle Fatigue During a Half-Iron Triathlon

PubMed Central

Coso, Juan Del; González-Millán, Cristina; Salinero, Juan José; Abián-Vicén, Javier; Soriano, Lidón; Garde, Sergio; Pérez-González, Benito

2012-01-01

Background To investigate the cause/s of muscle fatigue experienced during a half-iron distance triathlon. Methodology/Principal Findings We recruited 25 trained triathletes (36±7 yr; 75.1±9.8 kg) for the study. Before and just after the race, jump height and leg muscle power output were measured during a countermovement jump on a force platform to determine leg muscle fatigue. Body weight, handgrip maximal force and blood and urine samples were also obtained before and after the race. Blood myoglobin and creatine kinase concentrations were determined as markers of muscle damage. Results Jump height (from 30.3±5.0 to 23.4±6.4 cm; P<0.05) and leg power output (from 25.6±2.9 to 20.7±4.6 W · kg−1; P<0.05) were significantly reduced after the race. However, handgrip maximal force was unaffected by the race (430±59 to 430±62 N). Mean dehydration after the race was 2.3±1.2% with high inter-individual variability in the responses. Blood myoglobin and creatine kinase concentration increased to 516±248 µg · L−1 and 442±204 U · L−1, respectively (P<0.05) after the race. Pre- to post-race jump change did not correlate with dehydration (r = 0.16; P>0.05) but significantly correlated with myoglobin concentration (r = 0.65; P<0.001) and creatine kinase concentration (r = 0.54; P<0.001). Conclusions/significance During a half-iron distance triathlon, the capacity of leg muscles to produce force was notably diminished while arm muscle force output remained unaffected. Leg muscle fatigue was correlated with blood markers of muscle damage suggesting that muscle breakdown is one of the most relevant sources of muscle fatigue during a triathlon. PMID:22900101

Lower leg muscle density is independently associated with fall status in community-dwelling older adults.

PubMed

Frank-Wilson, A W; Farthing, J P; Chilibeck, P D; Arnold, C M; Davison, K S; Olszynski, W P; Kontulainen, S A

2016-07-01

Muscle density is a risk factor for fractures in older adults; however, its association with falls is not well described. After adjusting for biologically relevant confounding factors, a unit decrease in muscle density was associated with a 17 % increase in odds of reporting a fall, independent of functional mobility. Falls are the leading cause of injury, disability, and fractures in older adults. Low muscle density (i.e., caused by muscle adiposity) and functional mobility have been identified as risk factors for incident disability and fractures in older adults; however, it is not known if these are also independently associated with falls. The purpose of this study was to explore the associations of muscle density and functional mobility with fall status. Cross-sectional observational study of 183 men and women aged 60-98 years. Descriptive data, including a 12-month fall recall, Timed Up and Go (TUG) test performance, lower leg muscle area, and density. Odds ratio (OR) of being a faller were calculated, adjusted for age, sex, body mass index, general health status, diabetes, and comorbidities. Every mg/cm(3) increase in muscle density (mean 70.2, SD 2.6 mg/cm(3)) independently reduced the odds of being a faller by 19 % (OR 0.81 [95 % CI 0.67 to 0.97]), and every 1 s longer TUG test time (mean 9.8, SD 2.6 s) independently increased the odds by 17 % (OR 1.17 [95 % CI 1.01 to 1.37]). When both muscle density and TUG test time were included in the same model, only age (OR 0.93 [95 % CI 0.87 to 0.99]) and muscle density (OR 0.83 [95 % CI 0.69 to 0.99]) were independently associated with fall status. Muscle density was associated with fall status, independent of functional mobility. Muscle density may compliment functional mobility tests as a biometric outcome for assessing fall risk in well-functioning older adults.

Limb muscle quality and quantity in elderly adults with dynapenia but not sarcopenia: An ultrasound imaging study.

PubMed

Chang, Ke-Vin; Wu, Wei-Ting; Huang, Kuo-Chin; Jan, Wei Han; Han, Der-Sheng

2018-03-28

Dynapenia is prevalent in people with reduced skeletal muscle mass, i.e. sarcopenia, but a certain population develops muscle strength loss despite having normal skeletal muscle volume. To date, studies investigating muscle quality and quantity in groups with dynapenia but not sarcopenia are limited. Echogenicity and thickness of the biceps brachii, triceps brachii, rectus femoris, and medial gastrocnemius muscles were measured using high-resolution ultrasonography in 140 community-dwelling elderly adults. Participants with decreased handgrip strength but normal muscular volume were diagnosed as having dynapenia without sarcopenia. A multivariate regression model was used to analyze the association between dynapenia and ultrasound indicators of the sampled muscle expressed as odds ratio (OR) and 95% confidence interval (CI). A total of 140 participants were recruited for the study, 12.6% (n = 18) of whom had dynapenia. The dynapenia group had a higher mean age, higher proportion of women, slower fast gait speed, reduced handgrip strength, and decreased thicknesses of the biceps brachii, rectus femoris, and medial gastrocnemius muscles. On multivariate logistic regression analysis, dynapenia was associated with older age (OR, 1.18; 95% CI, 1.05 to 1.33), higher body mass index (OR, 1.28; 95% CI, 1.05 to 1.64), and decreased thicknesses of the rectus femoris (OR, 0.01; 95% CI, <0.01 to 0.24) and medial gastrocnemius muscles (OR, 0.03; 95% CI, <0.01 to 0.61). Dynapenia without sarcopenia is associated with decreased thicknesses of the rectus femoris and medial gastrocnemius muscles, an association that remains significant after adjustment for demographics, body composition, and physical performance. Ultrasound measurements of lower-limb muscle thickness can be considered an auxiliary criterion for evaluating dynapenia. Copyright © 2018 Elsevier Inc. All rights reserved.

Voluntary enhanced cocontraction of hamstring muscles during open kinetic chain leg extension exercise: its potential unloading effect on the anterior cruciate ligament.

PubMed

Biscarini, Andrea; Benvenuti, Paolo; Botti, Fabio M; Brunetti, Antonella; Brunetti, Orazio; Pettorossi, Vito E

2014-09-01

A number of research studies provide evidence that hamstring cocontraction during open kinetic chain knee extension exercises enhances tibiofemoral (TF) stability and reduces the strain on the anterior cruciate ligament. To determine the possible increase in hamstring muscle coactivation caused by a voluntary cocontraction effort during open kinetic chain leg-extension exercises, and to assess whether an intentional hamstring cocontraction can completely suppress the anterior TF shear force during these exercises. Descriptive laboratory study. Knee kinematics as well as electromyographic activity in the semitendinosus (ST), semimembranosus (SM), biceps femoris (BF), and quadriceps femoris muscles were measured in 20 healthy men during isotonic leg extension exercises with resistance (R) ranging from 10% to 80% of the 1-repetition maximum (1RM). The same exercises were also performed while the participants attempted to enhance hamstring coactivation through a voluntary cocontraction effort. The data served as input parameters for a model to calculate the shear and compressive TF forces in leg extension exercises for any set of coactivation patterns of the different hamstring muscles. For R≤ 40% 1RM, the peak coactivation levels obtained with intentional cocontraction (l) were significantly higher (P < 10(-3)) than those obtained without intentional cocontraction (l 0). For each hamstring muscle, maximum level l was reached at R = 30% 1RM, corresponding to 9.2%, 10.5%, and 24.5% maximum voluntary isometric contraction (MVIC) for the BF, ST, and SM, respectively, whereas the ratio l/l 0 reached its maximum at R = 20% 1RM and was approximately 2, 3, and 4 for the BF, SM, and ST, respectively. The voluntary enhanced coactivation level l obtained for R≤ 30% 1RM completely suppressed the anterior TF shear force developed by the quadriceps during the exercise. In leg extension exercises with resistance R≤ 40% 1RM, coactivation of the BF, SM, and ST can be

Ultrasound-Guided Injection of Botulinum Toxin Type A for Piriformis Muscle Syndrome: A Case Report and Review of the Literature

PubMed Central

Santamato, Andrea; Micello, Maria Francesca; Valeno, Giovanni; Beatrice, Raffaele; Cinone, Nicoletta; Baricich, Alessio; Picelli, Alessandro; Panza, Francesco; Logroscino, Giancarlo; Fiore, Pietro; Ranieri, Maurizio

2015-01-01

Piriformis muscle syndrome (PMS) is caused by prolonged or excessive contraction of the piriformis muscle associated with pain in the buttocks, hips, and lower limbs because of the close proximity to the sciatic nerve. Botulinum toxin type A (BoNT-A) reduces muscle hypertonia as well as muscle contracture and pain inhibiting substance P release and other inflammatory factors. BoNT-A injection technique is important considering the difficult access of the needle for deep location, the small size of the muscle, and the proximity to neurovascular structures. Ultrasound guidance is easy to use and painless and several studies describe its use during BoNT-A administration in PMS. In the present review article, we briefly updated current knowledge regarding the BoNT therapy of PMS, describing also a case report in which this syndrome was treated with an ultrasound-guided injection of incobotulinumtoxin A. Pain reduction with an increase of hip articular range of motion in this patient with PMS confirmed the effectiveness of BoNT-A injection for the management of this syndrome. PMID:26266421

PULSED FOCUSED ULTRASOUND TREATMENT OF MUSCLE MITIGATES PARALYSIS-INDUCED BONE LOSS IN THE ADJACENT BONE: A STUDY IN A MOUSE MODEL

PubMed Central

Poliachik, Sandra L.; Khokhlova, Tatiana D.; Wang, Yak-Nam; Simon, Julianna C.; Bailey, Michael R.

2015-01-01

Bone loss can result from bed rest, space flight, spinal cord injury or age-related hormonal changes. Current bone loss mitigation techniques include pharmaceutical interventions, exercise, pulsed ultrasound targeted to bone and whole body vibration. In this study, we attempted to mitigate paralysis-induced bone loss by applying focused ultrasound to the midbelly of a paralyzed muscle. We employed a mouse model of disuse that uses onabotulinumtoxinA-induced paralysis, which causes rapid bone loss in 5 d. A focused 2 MHz transducer applied pulsed exposures with pulse repetition frequency mimicking that of motor neuron firing during walking (80 Hz), standing (20 Hz), or the standard pulsed ultrasound frequency used in fracture healing (1 kHz). Exposures were applied daily to calf muscle for 4 consecutive d. Trabecular bone changes were characterized using micro-computed tomography. Our results indicated that application of certain focused pulsed ultrasound parameters was able to mitigate some of the paralysis-induced bone loss. PMID:24857416

Delivery of Na/I symporter gene into skeletal muscle using nanobubbles and ultrasound: visualization of gene expression by PET.

PubMed

Watanabe, Yukiko; Horie, Sachiko; Funaki, Yoshihito; Kikuchi, Youhei; Yamazaki, Hiromichi; Ishii, Keizo; Mori, Shiro; Vassaux, Georges; Kodama, Tetsuya

2010-06-01

The development of nonviral gene delivery systems is essential in gene therapy, and the use of a minimally invasive imaging methodology can provide important clinical endpoints. In the current study, we present a new methodology for gene therapy-a delivery system using nanobubbles and ultrasound as a nonviral gene delivery method. We assessed whether the gene transfer allowed by this methodology was detectable by PET and bioluminescence imaging. Two kinds of reported vectors (luciferase and human Na/I symporter [hNIS]) were transfected or cotransfected into the skeletal muscles of normal mice (BALB/c) using the ultrasound-nanobubbles method. The kinetics of luciferase gene expression were analyzed in vivo using bioluminescence imaging. At the peak of gene transfer, PET of hNIS expression was performed using our recently developed PET scanner, after (124)I injection. The imaging data were confirmed using reverse-transcriptase polymerase chain reaction amplification, biodistribution, and a blocking study. The imaging potential of the 2 methodologies was evaluated in 2 mouse models of human pathology (McH/lpr-RA1 mice showing vascular disease and C57BL/10-mdx Jic mice showing muscular dystrophy). Peak luciferase gene activity was observed in the skeletal muscle 4 d after transfection. On day 2 after hNIS and luciferase cotransfection, the expression of these genes was confirmed by reverse-transcriptase polymerase chain reaction on a muscle biopsy. PET of the hNIS gene, biodistribution, the blocking study, and autoradiography were performed on day 4 after transfection, and it was indicated that hNIS expression was restricted to the site of plasmid administration (skeletal muscle). Similar localized PET and (124)I accumulation were successfully obtained in the disease-model mice. The hNIS gene was delivered into the skeletal muscle of healthy and disease-model mice by the ultrasound-nanobubbles method, and gene expression was successfully visualized with PET. The

Oral antioxidants improve leg blood flow during exercise in patients with chronic obstructive pulmonary disease

PubMed Central

Rossman, Matthew J.; Trinity, Joel D.; Garten, Ryan S.; Ives, Stephen J.; Conklin, Jamie D.; Barrett-O'Keefe, Zachary; Witman, Melissa A. H.; Bledsoe, Amber D.; Morgan, David E.; Runnels, Sean; Reese, Van R.; Zhao, Jia; Amann, Markus; Wray, D. Walter

2015-01-01

The consequence of elevated oxidative stress on exercising skeletal muscle blood flow as well as the transport and utilization of O2 in patients with chronic obstructive pulmonary disease (COPD) is not well understood. The present study examined the impact of an oral antioxidant cocktail (AOC) on leg blood flow (LBF) and O2 consumption during dynamic exercise in 16 patients with COPD and 16 healthy subjects. Subjects performed submaximal (3, 6, and 9 W) single-leg knee extensor exercise while LBF (Doppler ultrasound), mean arterial blood pressure, leg vascular conductance, arterial O2 saturation, leg arterial-venous O2 difference, and leg O2 consumption (direct Fick) were evaluated under control conditions and after AOC administration. AOC administration increased LBF (3 W: 1,604 ± 100 vs. 1,798 ± 128 ml/min, 6 W: 1,832 ± 109 vs. 1,992 ± 120 ml/min, and 9W: 2,035 ± 114 vs. 2,187 ± 136 ml/min, P < 0.05, control vs. AOC, respectively), leg vascular conductance, and leg O2 consumption (3 W: 173 ± 12 vs. 210 ± 15 ml O2/min, 6 W: 217 ± 14 vs. 237 ± 15 ml O2/min, and 9 W: 244 ± 16 vs 260 ± 18 ml O2/min, P < 0.05, control vs. AOC, respectively) during exercise in COPD, whereas no effect was observed in healthy subjects. In addition, the AOC afforded a small, but significant, improvement in arterial O2 saturation only in patients with COPD. Thus, these data demonstrate a novel beneficial role of AOC administration on exercising LBF, O2 consumption, and arterial O2 saturation in patients with COPD, implicating oxidative stress as a potential therapeutic target for impaired exercise capacity in this population. PMID:26188020

Automatic segmentation of the puborectalis muscle in 3D transperineal ultrasound.

PubMed

van den Noort, Frieda; Grob, Anique T M; Slump, Cornelis H; van der Vaart, Carl H; van Stralen, Marijn

2017-10-11

The introduction of 3D analysis of the puborectalis muscle, for diagnostic purposes, into daily practice is hindered by the need for appropriate training of the observers. Automatic 3D segmentation of the puborectalis muscle in 3D transperineal ultrasound may aid to its adaption in clinical practice. A manual 3D segmentation protocol was developed to segment the puborectalis muscle. The data of 20 women, in their first trimester of pregnancy, was used to validate the reproducibility of this protocol. For automatic segmentation, active appearance models of the puborectalis muscle were developed. Those models were trained using manual segmentation data of 50 women. The performance of both manual and automatic segmentation was analyzed by measuring the overlap and distance between the segmentations. Also, the interclass correlation coefficients and their 95% confidence intervals were determined for mean echogenicity and volume of the puborectalis muscle. The ICC values of mean echogenicity (0.968-0.991) and volume (0.626-0.910) are good to very good for both automatic and manual segmentation. The results of overlap and distance for manual segmentation are as expected, showing only few pixels (2-3) mismatch on average and a reasonable overlap. Based on overlap and distance 5 mismatches in automatic segmentation were detected, resulting in an automatic segmentation a success rate of 90%. In conclusion, this study presents a reliable manual and automatic 3D segmentation of the puborectalis muscle. This will facilitate future investigation of the puborectalis muscle. It also allows for reliable measurements of clinically potentially valuable parameters like mean echogenicity. This article is protected by copyright. All rights reserved.

Quantifying Leg Movement Activity During Sleep.

PubMed

Ferri, Raffaele; Fulda, Stephany

2016-12-01

Currently, 2 sets of similar rules for recording and scoring leg movement (LM) exist, including periodic LM during sleep (PLMS) and periodic LM during wakefulness. The former were published in 2006 by a task force of the International Restless Legs Syndrome Study Group, and the second in 2007 by the American Academy of Sleep Medicine. This article reviews the basic recording methods, scoring rules, and computer-based programs for PLMS. Less frequent LM activities, such as alternating leg muscle activation, hypnagogic foot tremor, high-frequency LMs, and excessive fragmentary myoclonus are briefly described. Copyright © 2016 Elsevier Inc. All rights reserved.

Muscle power is an important measure to detect deficits in muscle function in hip osteoarthritis: a cross-sectional study.

PubMed

Bieler, Theresa; Magnusson, Stig Peter; Christensen, Helle Elisabeth; Kjaer, Michael; Beyer, Nina

2017-07-01

To investigate between-leg differences in hip and thigh muscle strength and leg extensor power in patients with unilateral hip osteoarthritis. Further, to compare between-leg differences in knee extensor strength and leg extensor power between patients and healthy peers. Seventy-two patients (60-87 years) with radiographic and symptomatic hip osteoarthritis not awaiting hip replacement and 35 healthy peers (63-82 years) were included. Hip and thigh muscle strength and leg extensor power were measured in patients and knee extensor strength and leg extensor power in healthy. The symptomatic extremity in patients was significantly (p < 0.05, paired t-test) weaker compared with the non-symptomatic extremity for five hip muscles (8-17%), knee extensors (11%) and leg extensor power (19%). Healthy older adults had asymmetry in knee extensor strength (6%, p < 0.05) comparable to that found in patients, but had no asymmetry in leg extensor power. Patients had generalized weakening of the affected lower extremity and numerically the largest asymmetry was evident for leg extensor power. In contrast, healthy peers had no asymmetry in leg extensor power. These results indicate that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with hip osteoarthritis. Implications for Rehabilitation Even in patients with mild symptoms not awaiting hip replacement a generalized muscle weakening of the symptomatic lower extremity seems to be present. Between-leg differences in leg extensor power (force × velocity) appears to be relatively large (19%) in patients with unilateral hip osteoarthritis in contrast to healthy peers who show no asymmetry. Compared to muscle strength the relationship between functional performance and leg extensor power seems to be stronger, and more strongly related to power of the symptomatic lower extremity. Our results indicate that exercise

Reliability study of tibialis posterior and selected leg muscle EMG and multi-segment foot kinematics in rheumatoid arthritis associated pes planovalgus

PubMed Central

Barn, Ruth; Rafferty, Daniel; Turner, Deborah E.; Woodburn, James

2012-01-01

Objective To determine within- and between-day reliability characteristics of electromyographic (EMG) activity patterns of selected lower leg muscles and kinematic variables in patients with rheumatoid arthritis (RA) and pes planovalgus. Methods Five patients with RA underwent gait analysis barefoot and shod on two occasions 1 week apart. Fine-wire (tibialis posterior [TP]) and surface EMG for selected muscles and 3D kinematics using a multi-segmented foot model was undertaken barefoot and shod. Reliability of pre-determined variables including EMG activity patterns and inter-segment kinematics were analysed using coefficients of multiple correlation, intraclass correlation coefficients (ICC) and the standard error of the measurement (SEM). Results Muscle activation patterns within- and between-day ranged from fair-to-good to excellent in both conditions. Discrete temporal and amplitude variables were highly variable across all muscle groups in both conditions but particularly poor for TP and peroneus longus. SEMs ranged from 1% to 9% of stance and 4% to 27% of maximum voluntary contraction; in most cases the 95% confidence interval crossed zero. Excellent within-day reliability was found for the inter-segment kinematics in both conditions. Between-day reliability ranged from fair-to-good to excellent for kinematic variables and all ICCs were excellent; the SEM ranged from 0.60° to 1.99°. Conclusion Multi-segmented foot kinematics can be reliably measured in RA patients with pes planovalgus. Serial measurement of discrete variables for TP and other selected leg muscles via EMG is not supported from the findings in this cohort of RA patients. Caution should be exercised when EMG measurements are considered to study disease progression or intervention effects. PMID:22721819

Limitations of oxygen uptake and leg muscle activity during ascending evacuation in stairways.

PubMed

Halder, Amitava; Kuklane, Kalev; Gao, Chuansi; Miller, Michael; Delin, Mattias; Norén, Johan; Fridolf, Karl

2018-01-01

Stair ascending performance is critical during evacuation from buildings and underground infrastructures. Healthy subjects performed self-paced ascent in three settings: 13 floor building, 31 floor building, 33 m stationary subway escalator. To investigate leg muscle and cardiorespiratory capacities and how they constrain performance, oxygen uptake (VO 2 ), heart rate (HR) and ascending speed were measured in all three; electromyography (EMG) in the first two. The VO 2 and HR ranged from 89 to 96% of the maximum capacity reported in the literature. The average highest VO 2 and HR ranged from 39 to 41 mL·kg -1 ·min -1 and 162 to 174 b·min -1 , respectively. The subjects were able to sustain their initial preferred maximum pace for a short duration, while the average step rate was 92-95 steps·min -1 . In average, VO 2 reached relatively stable values at ≈37 mL·kg -1 ·min -1 . EMG amplitudes decreased significantly and frequencies were unchanged. Speed reductions indicate that climbing capacity declined in the process of fatigue development. In the two buildings, the reduction of muscle power allowed the subjects to extend their tolerance and complete ascents in the 48 m and 109 m high stairways in 2.9 and 7.8 min, respectively. Muscle activity interpretation squares were developed and proved advantageous to observe fatigue and recovery over time. Copyright © 2017 Elsevier Ltd. All rights reserved.

M-Mode Ultrasound Reveals Earlier Gluteus Minimus Activity in Individuals With Chronic Hip Pain During a Step-down Task.

PubMed

Dieterich, Angela V; Deshon, Louise; Strauss, Geoffrey R; McKay, Jan; Pickard, Christine M

2016-04-01

Controlled laboratory study. The hip abductor muscles are important hip joint stabilizers. Hip joint pain may alter muscle recruitment. Motion-mode (M-mode) ultrasound enables noninvasive measurements of the onset of deep and superficial muscle motion, which is associated with activation onset. To compare (1) the onset of superficial and deep gluteus medius and gluteus minimus muscle motion relative to the instant of peak ground reaction force and (2) the level of swing-phase muscle motion during step-down between subjects with chronic hip pain and controls using M-mode ultrasound. Thirty-five subjects with anterior, nontraumatic hip pain for more than 6 months (mean ± SD age, 54 ± 9 years) and 35 controls (age, 57 ± 7 years) were scanned on the lateral hip of the leading leg during frontal step-down onto a force platform using M-mode ultrasound. Computerized motion detection with the Teager-Kaiser energy operator was applied on the gluteus minimus and the deep and superficial gluteus medius to determine the time lag between muscle motion onset and instant of peak ground reaction force and the level of gluteus minimus motion during the swing phase. Time lags and motion levels were averaged per subject, and t tests were used to determine between-group differences. In participants with hip pain, gluteus minimus motion onset was 103 milliseconds earlier (P = .002) and superficial gluteus medius motion was 70 milliseconds earlier (P = .047) than those in healthy control participants. The level of gluteus minimus swing-phase motion was higher with pain (P = .006). Increased gluteus minimus motion during the swing phase and earlier gluteus minimus and superficial gluteus medius motion in individuals with hip pain suggest an overall increase of muscle activity, possibly a protective behavior.

Venous leg ulcers

PubMed Central

2011-01-01

, pentoxifylline, rutosides, stanozolol, sulodexide, thromboxane alpha2 antagonists, zinc), peri-ulcer injection of granulocyte-macrophage colony-stimulating factor, self-help (advice to elevate leg, to keep leg active, to modify diet, to stop smoking, to reduce weight), short-stretch bandages, single-layer non-elastic system, skin grafting, superficial vein surgery, systemic mesoglycan, therapeutic ultrasound, and topical treatments (antimicrobial agents, autologous platelet lysate, calcitonin gene-related peptide plus vasoactive intestinal polypeptide, freeze-dried keratinocyte lysate, mesoglycan, negative pressure, recombinant keratinocyte growth factor, platelet-derived growth factor). PMID:22189344

Profiling Isokinetic Strength by Leg Preference and Position in Rugby Union Athletes.

PubMed

Brown, Scott R; Brughelli, Matt; Bridgeman, Lee A

2016-05-01

Muscle imbalances aid in the identification of athletes at risk for lower-extremity injury. Little is known regarding the influence that leg preference or playing position may have on lower-extremity muscle strength and asymmetry. To investigate lower-extremity strength profiles in rugby union athletes and compare isokinetic knee- and hip-strength variables between legs and positions. Thirty male academy rugby union athletes, separated into forwards (n = 15) and backs (n = 15), participated in this cross-sectional analysis. Isokinetic dynamometry was used to evaluate peak torque, angle of peak torque, and strength ratios of the preferred and nonpreferred legs during seated knee extension/flexion and supine hip extension/flexion at 60°/s. Backs were older (ES = 1.6) but smaller in stature (ES = -0.47) and body mass (ES = -1.3) than the forwards. The nonpreferred leg was weaker than the preferred leg for forwards during extension (ES = -0.37) and flexion (ES = -0.21) actions and for backs during extension (ES = -0.28) actions. Backs were weaker at the knee than forwards in the preferred leg during extension (ES = -0.50) and flexion (ES = -0.66) actions. No differences were observed in strength ratios between legs or positions. Backs produced peak torque at longer muscle lengths in both legs at the knee (ES = -0.93 to -0.94) and hip (ES = -0.84 to -1.17) than the forwards. In this sample of male academy rugby union athletes, the preferred leg and forwards displayed superior strength compared with the nonpreferred leg and backs. These findings highlight the importance of individualized athletic assessments to detect crucial strength differences in male rugby union athletes.

Dynamic postural stability for double-leg drop landing.

PubMed

Niu, Wenxin; Zhang, Ming; Fan, Yubo; Zhao, Qinping

2013-01-01

Dynamic postural stability has been widely studied for single-leg landing, but seldom considered for double-leg landing. This study aimed to evaluate the dynamic postural stability and the influence mechanism of muscle activities during double-leg drop landing. Eight recreationally active males and eight recreationally active females participated in this study and dropped individually from three heights (0.32 m, 0.52 m, and 0.72 m). Ground reaction force was recorded to calculate the time to stabilisation. Electromyographic activities were recorded for selected lower-extremity muscles. A multivariate analysis of variance was carried out and no significant influence was found in time to stabilisation between genders or limb laterals (P > 0.05). With increasing drop height, time to stabilisation decreased significantly in two horizontal directions and the lower-extremity muscle activities were enhanced. Vertical time to stabilisation was not significantly influenced by drop height. Dynamic postural stability improved by neuromuscular change more than that required due to the increase of drop height. Double-leg landing on level ground is a stable movement, and the body would often be injured before dynamic postural stability is impaired. It is understandable to protect tissues from mechanical injuries by the sacrifice of certain dynamic postural stability in the design of protective devices or athlete training.

Mechanical evidence that flamingos can support their body on one leg with little active muscular force.

PubMed

Chang, Young-Hui; Ting, Lena H

2017-05-01

Flamingos (Phoenicopteridae) often stand and sleep on one leg for long periods, but it is unknown how much active muscle contractile force they use for the mechanical demands of standing on one leg: body weight support and maintaining balance. First, we demonstrated that flamingo cadavers could passively support body weight on one leg without any muscle activity while adopting a stable, unchanging, joint posture resembling that seen in live flamingos. By contrast, the cadaveric flamingo could not be stably held in a two-legged pose, suggesting a greater necessity for active muscle force to stabilize two-legged versus one-legged postures. Our results suggest that flamingos engage a passively engaged gravitational stay apparatus (proximally located) for weight support during one-legged standing. Second, we discovered that live flamingos standing on one leg have markedly reduced body sway during quiescent versus alert behaviours, with the point of force application directly under the distal joint, reducing the need for muscular joint torque. Taken together, our results highlight the possibility that flamingos stand for long durations on one leg without exacting high muscular forces and, thus, with little energetic expenditure. © 2017 The Author(s).

Contribution of Leg-Muscle Forces to Paddle Force and Kayak Speed During Maximal-Effort Flat-Water Paddling.

PubMed

Nilsson, Johnny E; Rosdahl, Hans G

2016-01-01

The purpose was to investigate the contribution of leg-muscle-generated forces to paddle force and kayak speed during maximal-effort flat-water paddling. Five elite male kayakers at national and international level participated. The participants warmed up at progressively increasing speeds and then performed a maximal-effort, nonrestricted paddling sequence. This was followed after 5 min rest by a maximal-effort paddling sequence with the leg action restricted--the knee joints "locked." Left- and right-side foot-bar and paddle forces were recorded with specially designed force devices. In addition, knee angular displacement of the right and left knees was recorded with electrogoniometric technique, and the kayak speed was calculated from GPS signals sampled at 5 Hz. The results showed that reduction in both push and pull foot-bar forces resulted in a reduction of 21% and 16% in mean paddle-stroke force and mean kayak speed, respectively. Thus, the contribution of foot-bar force from lower-limb action significantly contributes to kayakers' paddling performance.

Strength, power output and symmetry of leg muscles: effect of age and history of falling.

PubMed

Perry, Mark C; Carville, Serena F; Smith, I Christopher H; Rutherford, Olga M; Newham, Di J

2007-07-01

Risk factors for medically unexplained falls may include reduced muscle power, strength and asymmetry in the lower limbs. Conflicting reports exist about strength and there is little information about power and symmetry. Forty-four healthy young people (29.3 +/- 0.6 years), 44 older non-fallers (75.9 +/- 0.6 years), and 34 older fallers (76.4 +/- 0.8 years) were studied. Isometric, concentric and eccentric strength of the knee and ankle muscles and leg extension power were measured bilaterally. The younger group was stronger in all muscles and types of contraction than both older groups (P < 0.02-0.0001). Strength differences between the older groups occasionally reached significance in individual muscles and types of contraction but overall the fallers had 85% of the strength and 79% of the power of the non-fallers (P < 0.001). Young subjects generated more power than both older groups (P < 0.0001) and the fallers generated less than the non-fallers (P = 0.03). Strength symmetry showed an inconsistent age effect in some muscles and some contraction types. This was similar overall in the two older groups. Both older groups had greater asymmetry in power than the young (P < 0.02-0.004). Power asymmetry tended to be greater in the fallers than the non-fallers but this did not reach significance. These data do not support the suggestion that asymmetry of strength and power are associated with either increasing age or fall history. Power output showed clear differences between age groups and fall status and appears to be the most relevant measurement of fall risk and highlights the cumulative effects on function of small changes in strength in individual muscle groups.

[Blood distribution in the human leg arteries during orthostasis: role of the hydrostatic factor and posturotonic straining of the anti-gravity muscles].

PubMed

Modin, A Iu

2004-01-01

Ultrasonic visualization and dopplerography were used to study volumetric blood flows along the femoral artery, deep artery of the thigh, and the popliteal and sural arteries in normal volunteers. Active standing test resulted in significant blood redistribution among the arteries with prioritized blood supply to predominantly anti-g muscles but not to predominantly locomotor muscles. Elimination of static loading on the anti-g muscles by weight removal (transfer of the body mass on the other leg) was conducive to the opposite effect, i.e. absolute and relative decreases in the intensity of blood flow along the sural artery and a relatively more marked blood redistribution toward the deep artery of the thigh.

Ultrasound evaluation of intrinsic plantar muscles and fascia in hallux valgus

PubMed Central

Lobo, César Calvo; Marín, Alejandro Garrido; Sanz, David Rodríguez; López, Daniel López; López, Patricia Palomo; Morales, Carlos Romero; Corbalán, Irene Sanz

2016-01-01

Abstract A cross-sectional area (CSA) and thickness reduction of the abductor hallucis (AbH) is shown in subjects with hallux valgus (HV). To date, other soft-tissue structures have not been researched in relation with HV. The aim of this study was to compare the CSA and thickness of the intrinsic plantar muscles and fascia (PF) between feet with and without HV. Therefore, a cross-sectional and case-control study was performed using B-mode with an iU22 Philips ultrasound system and a 5 to 17-MHz transducer. The CSA and thickness were measured for the AbH, flexor digitorum brevis (FDB) and flexor hallucis brevis (FHB), and also the thickness for the anterior, middle, and posterior PF portions. A convenience sample of 40 feet, 20 with HV and 20 without HV, was recruited from a clinical and research center. A multivariate regression analysis using linear regression was performed to evaluate the ultrasound imaging measurements (α = 0.05). Consequently, statistically significant differences were observed between the groups (P < 0.05) for the AbH and FHB thickness, and CSA reduction, and also the plantar fascia thickness increase in favor of the HV group. On the contrary, the FDB thickness and CSA did not show statistically significant differences (P ≥ 0.05). In conclusion, the CSA and thickness of the AbH and FHB intrinsic plantar muscles are reduced, whereas the thickness of the anterior, middle, and posterior PF portions are increased, in subjects with HV compared with those without HV. PMID:27828846

Venous leg ulcers

PubMed Central

2008-01-01

-ulcer injection of granulocyte-macrophage colony-stimulating factor, short-stretch bandages, single-layer non-elastic system, skin grafting, superficial vein surgery, systemic mesoglycan, therapeutic ultrasound, self-help (advice to elevate leg, advice to keep leg active, advice to modify diet, advice to stop smoking, advice to reduce weight), and topical treatments (antimicrobial agents, autologous platelet lysate, calcitonin gene-related peptide plus vasoactive intestinal polypeptide, freeze-dried keratinocyte lysate, mesoglycan, negative-pressure recombinant keratinocyte growth factor, platelet-derived growth factor). PMID:19445798

The effect of leg dominance and landing height on ACL loading among female athletes.

PubMed

Mokhtarzadeh, Hossein; Ewing, Katie; Janssen, Ina; Yeow, Chen-Hua; Brown, Nicholas; Lee, Peter Vee Sin

2017-07-26

Female athletes are more prone to anterior cruciate ligament (ACL) injury. A neuromuscular imbalance called leg dominance may provide a biomechanical explanation. Therefore, the purpose of this study was to compare the side-to-side lower limb differences in movement patterns, muscle forces and ACL forces during a single-leg drop-landing task from two different heights. We hypothesized that there will be significant differences in lower limb movement patterns (kinematics), muscle forces and ACL loading between the dominant and non-dominant limbs. Further, we hypothesized that significant differences between limbs will be present when participants land from a greater drop-landing height. Eight recreational female participants performed dominant and non-dominant single-leg drop landings from 30 to 60cm. OpenSim software was used to develop participant-specific musculoskeletal models and to calculate muscle forces. We also predicted ACL loading using our previously established method. There were no significant differences between dominant and non-dominant leg landing except in ankle dorsiflexion and GMED muscle forces at peak GRF. Landing from a greater height resulted in significant differences among most kinetics and kinematics variables and ACL forces. Minimal differences in lower-limb muscle forces and ACL loading between the dominant and non-dominant legs during single-leg landing may suggest similar risk of injury across limbs in this cohort. Further research is required to confirm whether limb dominance may play an important role in the higher incidence of ACL injury in female athletes with larger and sport-specific cohorts. Copyright © 2017 Elsevier Ltd. All rights reserved.

High-Resolution Nerve Ultrasound and Electrophysiological Findings in Restless Legs Syndrome.

PubMed

Pitarokoili, K; Fels, M; Kerasnoudis, A; Toenges, L; Gold, R; Yoon, M-S

2018-05-11

Restless legs syndrome (RLS) is a multifactorial network disorder of a sensorimotor system extending from dopaminergic and glutamatergic cerebral structures to the spinal neurons and peripheral nerves. The role of peripheral nerve damage in the causality and severity progression for RLS patients remains unclear. We performed a clinical and epidemiological study on a cohort of 34 RLS patients focusing on RLS risk factors and disease severity. We investigated the peripheral nerves with nerve conduction studies and with high-resolution nerve ultrasound (HRUS). In 18 of the 34 patients (mean age 67.4 ± 15 years old), a sensorimotor axonal neuropathy was diagnosed. These patients presented with late-onset RLS were treated with membrane stabilizing agents, whereas no neuropathy predisposing comorbidity could be identified for the majority of them. We could show an inverse correlation between the amplitudes of the tibial nerve for the patients with polyneuropathy and the RLS severity index. Neuropathy patients were characterized by an increase of the cross-sectional area (CSA) of the tibial nerve in the popliteal fossa and by increased intranerve and internerve variability values showing an asymmetry of CSA distribution. This pattern resembles previous studies on diabetic neuropathy. Early diagnosis, characterization, and treatment of neuropathy are increasingly relevant for RLS patients as it correlates with disease severity. HRUS revealed a pattern resembling diabetic neuropathy, which implies a similar pathophysiology with metabolic and ischemic origin of RLS-related axonal neuropathy. Copyright © 2018 by the American Society of Neuroimaging.

Precooling leg muscle improves intermittent sprint exercise performance in hot, humid conditions.

PubMed

Castle, Paul C; Macdonald, Adam L; Philp, Andrew; Webborn, Anthony; Watt, Peter W; Maxwell, Neil S

2006-04-01

We used three techniques of precooling to test the hypothesis that heat strain would be alleviated, muscle temperature (Tmu) would be reduced, and as a result there would be delayed decrements in peak power output (PPO) during exercise in hot, humid conditions. Twelve male team-sport players completed four cycling intermittent sprint protocols (CISP). Each CISP consisted of twenty 2-min periods, each including 10 s of passive rest, 5 s of maximal sprint against a resistance of 7.5% body mass, and 105 s of active recovery. The CISP, preceded by 20 min of no cooling (Control), precooling via an ice vest (Vest), cold water immersion (Water), and ice packs covering the upper legs (Packs), was performed in hot, humid conditions (mean +/- SE; 33.7 +/- 0.3 degrees C, 51.6 +/- 2.2% relative humidity) in a randomized order. The rate of heat strain increase during the CISP was faster in Control than Water and Packs (P < 0.01), but it was similar to Vest. Packs and Water blunted the rise of Tmu until minute 16 and for the duration of the CISP (40 min), respectively (P < 0.01). Reductions in PPO occurred from minute 32 onward in Control, and an increase in PPO by approximately 4% due to Packs was observed (main effect; P < 0.05). The method of precooling determined the extent to which heat strain was reduced during intermittent sprint cycling, with leg precooling offering the greater ergogenic effect on PPO than either upper body or whole body cooling.

Distal muscle activity alterations during the stance phase of gait in restless leg syndrome (RLS) patients.

PubMed

Dafkin, Chloe; Green, Andrew; Olivier, Benita; McKinon, Warrick; Kerr, Samantha

2018-05-01

To assess if there is a circadian variation in electromyographical (EMG) muscle activity during gait in restless legs syndrome (RLS) patients and healthy control participants. Gait assessment was done in 14 RLS patients and 13 healthy control participants in the evening (PM) and the morning (AM). Muscle activity was recorded bilaterally from the tibialis anterior (TA), lateral gastrocnemius (GL), rectus femoris (RF) and biceps femoris (BF) muscles. A circadian variation during the stance phase in only TA (PM > AM, p < 0.005) and BF (PM < AM, p = 0.008) activity was observed in control participants. Conversely no circadian variation was seen in any muscles in the RLS patients. RLS patients had an increased TA and GL activity (RLS > Controls, p < 0.05) during early stance and decreased GL activity (RLS < Controls, p < 0.01) during terminal stance in comparison to control participants in the evening. No other significant differences were noted between RLS patients and control participants. Activation of GL during the swing phase was noted in 79% of RLS patients and in 23% of control participants in the morning compared to 71% and 38% in the evening, respectively. EMG muscle activity shows no circadian variation in RLS patients. Evening differences in gait muscle activation patterns between RLS patients and control participants are evident. These results extend our knowledge about alterations in spinal processing during gait in RLS. A possible explanation for these findings is central pattern generator sensitization caused by increased sensitivity in cutaneous afferents in RLS patients. Copyright © 2018 Elsevier B.V. All rights reserved.

Muscle stiffness of posterior lower leg in runners with a history of medial tibial stress syndrome.

PubMed

Saeki, J; Nakamura, M; Nakao, S; Fujita, K; Yanase, K; Ichihashi, N

2018-01-01

Previous history of medial tibial stress syndrome (MTSS) is a risk factor for MTSS relapse, which suggests that there might be some physical factors that are related to MTSS development in runners with a history of MTSS. The relationship between MTSS and muscle stiffness can be assessed in a cross-sectional study that measures muscle stiffness in subjects with a history of MTSS, who do not have pain at the time of measurement, and in those without a history of MTSS. The purpose of this study was to compare the shear elastic modulus, which is an index of muscle stiffness, of all posterior lower leg muscles of subjects with a history of MTSS and those with no history and investigate which muscles could be related to MTSS. Twenty-four male collegiate runners (age, 20.0±1.7 years; height, 172.7±4.8 cm; weight, 57.3±3.7 kg) participated in this study; 14 had a history of MTSS, and 10 did not. The shear elastic moduli of the lateral gastrocnemius, medial gastrocnemius, soleus, peroneus longus, peroneus brevis, flexor hallucis longus, flexor digitorum longus, and tibialis posterior were measured using shear wave elastography. The shear elastic moduli of the flexor digitorum longus and tibialis posterior were significantly higher in subjects with a history of MTSS than in those with no history. However, there was no significant difference in the shear elastic moduli of other muscles. The results of this study suggest that flexor digitorum longus and tibialis posterior stiffness could be related to MTSS. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Interdependence of torque, joint angle, angular velocity and muscle action during human multi-joint leg extension.

PubMed

Hahn, Daniel; Herzog, Walter; Schwirtz, Ansgar

2014-08-01

Force and torque production of human muscles depends upon their lengths and contraction velocity. However, these factors are widely assumed to be independent of each other and the few studies that dealt with interactions of torque, angle and angular velocity are based on isolated single-joint movements. Thus, the purpose of this study was to determine force/torque-angle and force/torque-angular velocity properties for multi-joint leg extensions. Human leg extension was investigated (n = 18) on a motor-driven leg press dynamometer while measuring external reaction forces at the feet. Extensor torque in the knee joint was calculated using inverse dynamics. Isometric contractions were performed at eight joint angle configurations of the lower limb corresponding to increments of 10° at the knee from 30 to 100° of knee flexion. Concentric and eccentric contractions were performed over the same range of motion at mean angular velocities of the knee from 30 to 240° s(-1). For contractions of increasing velocity, optimum knee angle shifted from 52 ± 7 to 64 ± 4° knee flexion. Furthermore, the curvature of the concentric force/torque-angular velocity relations varied with joint angles and maximum angular velocities increased from 866 ± 79 to 1,238 ± 132° s(-1) for 90-50° knee flexion. Normalised eccentric forces/torques ranged from 0.85 ± 0.12 to 1.32 ± 0.16 of their isometric reference, only showing significant increases above isometric and an effect of angular velocity for joint angles greater than optimum knee angle. The findings reveal that force/torque production during multi-joint leg extension depends on the combined effects of angle and angular velocity. This finding should be accounted for in modelling and optimisation of human movement.

Modulation of corticospinal input to the legs by arm and leg cycling in people with incomplete spinal cord injury.

PubMed

Zhou, R; Alvarado, L; Kim, S; Chong, S L; Mushahwar, V K

2017-10-01

The spinal cervico-lumbar interaction during rhythmic movements in humans has recently been studied; however, the role of arm movements in modulating the corticospinal drive to the legs is not well understood. The goals of this study were to investigate the effect of active rhythmic arm movements on the corticospinal drive to the legs ( study 1 ) and assess the effect of simultaneous arm and leg training on the corticospinal pathway after incomplete spinal cord injury (iSCI) ( study 2). In study 1 , neurologically intact (NI) participants or participants with iSCI performed combinations of stationary and rhythmic cycling of the arms and legs while motor evoked potentials (MEPs) were recorded from the vastus lateralis (VL) muscle. In the NI group, arm cycling alone could facilitate the VL MEP amplitude, suggesting that dynamic arm movements strongly modulate the corticospinal pathway to the legs. No significant difference in VL MEP between conditions was found in participants with iSCI. In study 2 , participants with iSCI underwent 12 wk of electrical stimulation-assisted cycling training: one group performed simultaneous arm and leg (A&L) cycling and the other legs-only cycling. MEPs in the tibialis anterior (TA) muscle were compared before and after training. After training, only the A&L group had a significantly larger TA MEP, suggesting increased excitability in the corticospinal pathway. The findings demonstrate the importance of arm movements in modulating the corticospinal drive to the legs and suggest that active engagement of the arms in lower limb rehabilitation may produce better neural regulation and restoration of function. NEW & NOTEWORTHY This study aimed to demonstrate the importance of arm movements in modulating the corticospinal drive to the legs. It provides direct evidence in humans that active movement of the arms could facilitate corticospinal transmission to the legs and, for the first time, shows that facilitation is absent after spinal cord

Ultrasound Assessment of Abdominal Muscle Thickness in Postpartum vs Nulliparous Women.

PubMed

Weis, Carol Ann; Triano, John J; Barrett, Jon; Campbell, Michelle D; Croy, Martine; Roeder, Jessica

2015-06-01

The purpose of this study was to determine the effect size in measurable change of abdominal musculature morphology using ultrasonography in postpartum women within 1 month of a healthy, vaginal delivery. One hundred fifty-six participants were recruited for this study. B-mode ultrasound imaging was used to measure abdominal muscle thickness on 80 nulliparous women and 76 mothers who had delivered within the past 4 weeks. Measures were taken for the upper and lower rectus abdominus, external and internal obliques, and transversus abdominus at rest. Statistically significant differences were found in the thickness of the rectus abdominus muscle at both sites; upper (P < .0001) and lower (P < .0001) as well as the internal oblique (P < .0001). All 3 muscles were thinner in postpartum participants (8.29 ± 1.83 mm, 8.89 ± 2.29 mm, and 7.06 ± 1.82 mm, respectively) within the first month of delivery than in controls (10.82 ± 1.93 mm, 11.13 ± 2.38 mm, and 8.36 ± 1.87 mm, respectively). Large effect sizes were found for the influence of pregnancy on the rectus muscle segments (1.35 for the upper rectus abdominus and 1.00 for the lower rectus abdominus) and a medium effect size for the internal oblique (0.71). No significant differences were observed in the remaining 2 muscles. This study showed that there are differences in morphology of the abdominal muscles in pregnant women vs nonpregnant controls. The large effect sizes reported may provide the basis for future studies examining relationships between morphology, functional change, and back pain during pregnancy. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

[Physical treatment modalities for chronic leg ulcers].

PubMed

Dissemond, J

2010-05-01

An increasing numbers of physical treatment options are available for chronic leg ulcer. In this review article, compression therapy, therapeutic ultrasound, negative pressure therapy, extracorporeal shock wave therapy, electrostimulation therapy, electromagnetic therapy, photodynamic therapy, water-filtered infrared-A-radiation and hydrotherapy are discussed in terms of their practical applications and the underlying evidence. With the exception of compression therapy for most of these treatments, good scientific data are not available. However this is a widespread problem in the treatment of chronic wounds. Nevertheless, several of the described methods such as negative pressure therapy represent one of the gold standards in practical treatment of patients with chronic leg ulcers. Although the use of physical treatment modalities may improve healing in patients with chronic leg ulcers, the diagnosis and treatment of the underlying causes are essential for long-lasting success.

Hip proprioceptors preferentially modulate reflexes of the leg in human spinal cord injury

PubMed Central

Onushko, Tanya; Hyngstrom, Allison

2013-01-01

Stretch-sensitive afferent feedback from hip muscles has been shown to trigger long-lasting, multijoint reflex responses in people with chronic spinal cord injury (SCI). These reflexes could have important implications for control of leg movements during functional activities, such as walking. Because the control of leg movement relies on reflex regulation at all joints of the limb, we sought to determine whether stretch of hip muscles modulates reflex activity at the knee and ankle and, conversely, whether knee and ankle stretch afferents affect hip-triggered reflexes. A custom-built servomotor apparatus was used to stretch the hip muscles in nine chronic SCI subjects by oscillating the legs about the hip joint bilaterally from 10° of extension to 40° flexion. To test whether stretch-related feedback from the knee or ankle would be affected by hip movement, patellar tendon percussions and Achilles tendon vibration were delivered when the hip was either extending or flexing. Surface electromyograms (EMGs) and joint torques were recorded from both legs. Patellar tendon percussions and Achilles tendon vibration both elicited reflex responses local to the knee or ankle, respectively, and did not influence reflex responses observed at the hip. Rather, the movement direction of the hip modulated the reflex responses local to the joint. The patellar tendon reflex amplitude was larger when the perturbation was delivered during hip extension compared with hip flexion. The response to Achilles vibration was modulated by hip movement, with an increased tonic component during hip flexion compared with extension. These results demonstrate that hip-mediated sensory signals modulate activity in distal muscles of the leg and appear to play a unique role in modulation of spastic muscle activity throughout the leg in SCI. PMID:23615544

Intravenous Delivery of pDNA and siRNA into Muscle with Bubble Liposomes and Ultrasound

NASA Astrophysics Data System (ADS)

Negishi, Yoichi; Sekine, Shohko; Endo, Yoko; Nishijima, Nobuaki; Suzuki, Ryo; Maruyama, Kazuo; Aramaki, Yukihiko

2010-03-01

Skeletal muscle is an attractive target tissue for numerous gene therapy strategies. Gene delivery into muscle has been extensively studied. Of the strategies, intravascular delivery of naked pDNA is desirable. Muscle has a high density of capillaries that are in close contact with myofibers. Previously, we developed polyethylene glycol (PEG)-modified liposomes entrapping echo-contrast gas, known as ultrasound (US) imaging gas. We called the liposomes "Bubble liposomes" (BLs). It has been reported that BLs improve the tissue permeability by cavitation on US exposure. Here, we modified the naked pDNA or siRNA transfer method into hind limb muscle through blood vessels using BLs and US. The intravenous delivery of pDNA into muscle can be markedly enhanced when the pDNA is delivered in combination with BLs and US. In addition, the expression of pDNA is high in the US-focused site. Moreover, efficient gene delivery can be achieved by the intravenous delivery of pDNA into muscle with BLs and US. Expression is also down-regulated by delivering siRNA with BLs and US. Thus, this US-mediated BL technique involving veins may be an effective method for gene therapy.

Athletes' leg pains.

PubMed Central

Orava, S.; Puranen, J.

1979-01-01

The frequency and nature of exertion pains of the leg in athletes were studied in 2,750 cases of overuse injuries treated at the Sports Clinic of the Deaconess Institute of Oulu, Finland, during the years 1972-1977. 465 cases of exertion pain (18%) were located in the shin. The medial tibial syndrome was the most common overuse injury among these athletes, comprising 9.5% of all exertion injuries and 60% of the leg exertion pains. Together with stress fracture of the tibia, the second most common exertion pain of the leg, it accounted for 75% of the total leg pains. There are certain difficulties in differentiating between the medial tibial syndrome and stress fracture of the tibia. They both occur at the same site with similar symptoms. Radiological examination and isotope scanning are needed. The medial tibial syndrome is an overuse injury at the medial tibial border caused by running exercises. The pain is elicited by exertional ischaemia. The pathogenesis is explained by increased pressure in the fascial compartment of the deep flexor muscles due to prolonged exercise. Similar chronic ischaemic pains from exercise are also found in other fascial compartments of the leg, especially in the anterior compartment. The only treatment needed for stress fractures is rest from training. Fascial compartment pains also usually subside. If chronic fascial syndromes prevent training, fasciotomy is recommended as a reliable method to restore the athlete to normal training without pains. PMID:486888

Intermuscular relationship of human muscle fiber type proportions: slow leg muscles predict slow neck muscles.

PubMed

Vikne, Harald; Gundersen, Kristian; Liestøl, Knut; Maelen, Jan; Vøllestad, Nina

2012-04-01

Our aim in this study was to examine whether the muscle fiber type proportions in different muscles from the same individual are interrelated. Samples were excised from five skeletal muscles in each of 12 human autopsy cases, and the fiber type proportions were determined by immunohistochemistry. We further examined the intermuscular relationship in fiber type proportion by reanalyzing three previously published data sets involving other muscles. Subjects demonstrated a predominantly high or low proportion of type 1 fibers in all examined muscles, and the overall difference between individuals was statistically significant (P < 0.001). Accordingly, the type 1 fiber proportions in most muscles were positively correlated (median r = 0.42, range -0.03-0.80). Similar results were also obtained from the three reanalyzed data sets. We suggest the existence of an across-muscle phenotype with respect to fiber type proportions; some individuals display generally faster muscles and some individuals slower muscles when compared with others. Copyright © 2011 Wiley Periodicals, Inc.

Why do flamingos stand on one leg?

PubMed

Anderson, Matthew J; Williams, Sarah A

2010-01-01

A series of observational studies of captive Caribbean flamingos Phoenicopterus ruber were conducted to determine why flamingos rest on one leg. While frequently asked by the general public, this basic question has remained unanswered by the scientific community. Here we suggest that the latency of flamingos to initiate forward locomotion following resting on one leg is significantly longer than following resting on two, discounting the possibility that unipedal resting reduces muscle fatigue or enhances predatory escape. Additionally, we demonstrate that flamingos do not display lateral preferences at the individual or group levels when resting on one leg, with each bird dividing its resting time across both legs. We show that while flamingos prefer resting on one leg to two regardless of location, the percentage of birds resting on one leg is significantly higher among birds standing in the water than among those on land. Finally, we demonstrate a negative relationship between temperature and the percentage of observed birds resting on one leg, such that resting on one leg decreases as temperature rises. Results strongly suggest that unipedal resting aids flamingos in thermoregulation. (c) 2009 Wiley-Liss, Inc.

Anatomic and functional leg-length inequality: A review and recommendation for clinical decision-making. Part II, the functional or unloaded leg-length asymmetry

PubMed Central

Knutson, Gary A

2005-01-01

Background Part II of this review examines the functional "short leg" or unloaded leg length alignment asymmetry, including the relationship between an anatomic and functional leg-length inequality. Based on the reviewed evidence, an outline for clinical decision making regarding functional and anatomic leg-length inequality will be provided. Methods Online databases: Medline, CINAHL and Mantis. Plus library searches for the time frame of 1970–2005 were done using the term "leg-length inequality". Results and Discussion The evidence suggests that an unloaded leg-length asymmetry is a different phenomenon than an anatomic leg-length inequality, and may be due to suprapelvic muscle hypertonicity. Anatomic leg-length inequality and unloaded functional or leg-length alignment asymmetry may interact in a loaded (standing) posture, but not in an unloaded (prone/supine) posture. Conclusion The unloaded, functional leg-length alignment asymmetry is a likely phenomenon, although more research regarding reliability of the measurement procedure and validity relative to spinal dysfunction is needed. Functional leg-length alignment asymmetry should be eliminated before any necessary treatment of anatomic LLI. PMID:16080787

Quantitative muscle ultrasound is useful for evaluating secondary axonal degeneration in chronic inflammatory demyelinating polyneuropathy.

PubMed

Hokkoku, Keiichi; Matsukura, Kiyoshi; Uchida, Yudai; Kuwabara, Midori; Furukawa, Yuichi; Tsukamoto, Hiroshi; Hatanaka, Yuki; Sonoo, Masahiro

2017-10-01

In chronic inflammatory demyelinating polyneuropathy (CIDP), exclusion of secondary axonal degeneration is challenging with conventional methods such as nerve conduction study (NCS), needle electromyography, and nerve biopsy. Increased echo intensity (EI) and decreased muscle thickness (MT) identified on muscle ultrasound (MUS) examination represent muscle denervation due to axonal degeneration in neurogenic disorders, suggesting MUS as a new tool to detect secondary axonal degeneration in patients with CIDP. EI and MT of abductor pollicis brevis, abductor digiti minimi, and first dorsal interosseous muscles were measured in 16 CIDP patients. Raw values were converted into z -scores using data from 60 normal controls (NCs). Six of 45 muscles showed abnormally high EI and low MT, suggesting denervation following secondary axonal degeneration. These six muscles belonged to two patients with long disease history, unresponsiveness to treatment, and long interval from onset to initial therapy. There were no significant differences in EI and MT ( p  = .23 and .67, respectively) between the CIDP and NC groups, although NCS results revealed obvious demyelinating abnormalities in all CIDP patients, suggesting the fact that muscle structures will be preserved, and EI and MT will not change unless secondary axonal degeneration occurs in CIDP. MUS is a promising tool for evaluating secondary axonal degeneration in patients with CIDP.

Ultrasound evaluation of foot muscles and plantar fascia in pes planus.

PubMed

Angin, Salih; Crofts, Gillian; Mickle, Karen J; Nester, Christopher J

2014-01-01

Multiple intrinsic and extrinsic soft tissue structures that apply forces and support the medial longitudinal arch have been implicated in pes planus. These structures have common functions but their interaction in pes planus is not fully understood. The aim of this study was to compare the cross-sectional area (CSA) and thickness of the intrinsic and extrinsic foot muscles and plantar fascia thickness between normal and pes planus feet. Forty-nine adults with a normal foot posture and 49 individuals with pes planus feet were recruited from a university population. Images of the flexor digitorum longus (FDL), flexor hallucis longus (FHL), peroneus longus and brevis (PER), flexor hallucis brevis (FHB), flexor digitorum brevis (FDB) and abductor hallucis (AbH) muscles and the plantar fascia were obtained using a Venue 40 ultrasound system with a 5-13 MHz transducer. The CSA and thickness of AbH, FHB and PER muscles were significantly smaller (AbH -12.8% and -6.8%, FHB -8.9% and -7.6%, PER -14.7% and -10%), whilst FDL (28.3% and 15.2%) and FHL (24% and 9.8%) were significantly larger in the pes planus group. The middle (-10.6%) and anterior (-21.7%) portions of the plantar fascia were thinner in pes planus group. Greater CSA and thickness of the extrinsic muscles might reflect compensatory activity to support the MLA if the intrinsic foot muscle function has been compromised by altered foot structure. A thinner plantar fascia suggests reduced load bearing, and regional variations in structure and function in feet with pes planus. Copyright © 2014 Elsevier B.V. All rights reserved.

Muscle anatomy and dynamic muscle function in osteogenesis imperfecta type I.

PubMed

Veilleux, Louis-Nicolas; Lemay, Martin; Pouliot-Laforte, Annie; Cheung, Moira S; Glorieux, Francis H; Rauch, Frank

2014-02-01

Results of previous studies suggested that children and adolescents with osteogenesis imperfecta (OI) type I have a muscle force deficit. However, muscle function has only been assessed by static isometric force tests and not in more natural conditions such as dynamic force and power tests. The purpose of this study was to assess lower extremity dynamic muscle function and muscle anatomy in OI type I. The study was performed in the outpatient department of a pediatric orthopedic hospital. A total of 54 individuals with OI type I (6-21 years; 20 male) and 54 age- and sex-matched controls took part in this study. Calf muscle cross-sectional area and density were measured by peripheral quantitative computed tomography. Lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by jumping mechanography through 5 tests: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test. Compared with age- and sex-matched controls, patients with OI type I had smaller muscle size (P = .04) but normal muscle density (P = .21). They also had lower average peak force and lower specific force (peak force/muscle cross-sectional area; all P < .008). Average peak power was lower in patients with OI type I but not significantly so (all P > .054). Children and adolescents with OI type I have, on average, a significant force deficit in the lower limb as measured by dynamic force tests. Nonetheless, these data also show that OI type I is compatible with normal muscle performance in some individuals.

Changes in B-mode ultrasound echo intensity following injection of bupivacaine hydrochloride to rat hind limb muscles in relation to histologic changes.

PubMed

Fujikake, T; Hart, R; Nosaka, Kazunori

2009-04-01

This study tested the hypothesis that infiltration of inflammatory cells in muscle fibers would increase echo intensity (image brightness) of B-mode ultrasound images. Bupivacaine hydrochloride (BPVC) or saline solution (SAL) was injected to the tibialis anterior (TA) muscles of 14- to 23-wk-old male Wistar rats. Ultrasound images were taken from the muscles before and at 0, 2, 4, 6, 9, 12, 24, 48, 72, 120, 168 and 336 h after the injection and analyzed for the echo intensity (echogenicity) expressed as the mean value of image pixel value of a region-of-interest. Changes in the echo intensity were compared between BPVC-injected and control or SAL-injected muscles. In the subsequent study, rats (n = 2 per time point) were sacrificed after taking ultrasound image at 0, 2, 6, 12, 24, 48 and 168 h after BPVC injection to the right TA and SAL injection to the left TA to observe histologic changes under a light microscope and the relationship between echo intensity and inflammatory cells was assessed. No significant changes in echo intensity were observed for the control, but BPVC induced significant (p < 0.05) increases in the echo intensity peaking 0 to 24 h postinjection. SAL also increased echo intensity immediately after injection but returned to the baseline by 24 h postinjection. The time course of changes in the echo intensity did not match with the time course of increases in inflammatory cells in the muscle. It is concluded that infiltration of inflammatory cells is not a direct cause of the increased echo intensity.

Three-dimensional ultrasound strain imaging of skeletal muscles

NASA Astrophysics Data System (ADS)

Gijsbertse, K.; Sprengers, A. M. J.; Nillesen, M. M.; Hansen, H. H. G.; Lopata, R. G. P.; Verdonschot, N.; de Korte, C. L.

2017-01-01

In this study, a multi-dimensional strain estimation method is presented to assess local relative deformation in three orthogonal directions in 3D space of skeletal muscles during voluntary contractions. A rigid translation and compressive deformation of a block phantom, that mimics muscle contraction, is used as experimental validation of the 3D technique and to compare its performance with respect to a 2D based technique. Axial, lateral and (in case of 3D) elevational displacements are estimated using a cross-correlation based displacement estimation algorithm. After transformation of the displacements to a Cartesian coordinate system, strain is derived using a least-squares strain estimator. The performance of both methods is compared by calculating the root-mean-squared error of the estimated displacements with the calculated theoretical displacements of the phantom experiments. We observe that the 3D technique delivers more accurate displacement estimations compared to the 2D technique, especially in the translation experiment where out-of-plane motion hampers the 2D technique. In vivo application of the 3D technique in the musculus vastus intermedius shows good resemblance between measured strain and the force pattern. Similarity of the strain curves of repetitive measurements indicates the reproducibility of voluntary contractions. These results indicate that 3D ultrasound is a valuable imaging tool to quantify complex tissue motion, especially when there is motion in three directions, which results in out-of-plane errors for 2D techniques.

Biological response in vitro of skeletal muscle cells treated with different intensity continuous and pulsed ultrasound fields

NASA Astrophysics Data System (ADS)

Abrunhosa, Viviane M.; Mermelstein, Claudia S.; Costa, Manoel L.; Costa-Felix, Rodrigo P. B.

2011-02-01

Therapeutic ultrasound has been used in physiotherapy to accelerate tissue healing. Although the ultrasonic wave is widely used in clinical practice, not much is known about the biological effects of ultrasound on cells and tissues. This study aims to evaluate the biological response of ultrasound in primary cultures of chick myogenic cells. To ensure the metrological reliability of whole measurement process, the ultrasound equipment was calibrated in accordance with IEC 61689:2007. The skeletal muscle cells were divided in four samples. One sample was used as a control group and the others were submitted to different time and intensity and operation mode of ultrasound: 1) 0.5 W/cm2 continuous for 5 minutes, 2) 0.5 W/cm2 pulsed for 5 minutes, 3) 1.0 W/cm2 pulsed for 10 minutes. The samples were analyzed with phase contrast optical microscopy before and after the treatment. The results showed alignment of myogenic cells in the sample treated with 0.5 W/cm2 continuous during 5 minutes when compared with the control group and the other samples. This study is a first step towards a metrological and scientific based protocol to cells and tissues treatment under different ultrasound field exposures.

The Motor and the Brake of the Trailing Leg in Human Walking: Leg Force Control Through Ankle Modulation and Knee Covariance

PubMed Central

Toney, Megan E.; Chang, Young-Hui

2016-01-01

Human walking is a complex task, and we lack a complete understanding of how the neuromuscular system organizes its numerous muscles and joints to achieve consistent and efficient walking mechanics. Focused control of select influential task-level variables may simplify the higher-level control of steady state walking and reduce demand on the neuromuscular system. As trailing leg power generation and force application can affect the mechanical efficiency of step-to-step transitions, we investigated how joint torques are organized to control leg force and leg power during human walking. We tested whether timing of trailing leg force control corresponded with timing of peak leg power generation. We also applied a modified uncontrolled manifold analysis to test whether individual or coordinated joint torque strategies most contributed to leg force control. We found that leg force magnitude was adjusted from step-to-step to maintain consistent leg power generation. Leg force modulation was primarily determined by adjustments in the timing of peak ankle plantar-flexion torque, while knee torque was simultaneously covaried to dampen the effect of ankle torque on leg force. We propose a coordinated joint torque control strategy in which the trailing leg ankle acts as a motor to drive leg power production while trailing leg knee torque acts as a brake to refine leg power production. PMID:27334888

Differentiation of original and regenerated skeletal muscle fibres in mdx dystrophic muscles.

PubMed

Earnshaw, John C; Kyprianou, Phillip; Krishan, Kewal; Dhoot, Gurtej K

2002-07-01

The differentiation of both original muscle fibres and the regenerated muscle fibres following necrosis in mdx muscles was investigated using immunoblotting and immunocytochemical procedures. Before the onset of necrosis, postnatal skeletal muscles in mdx mouse differentiated well with only a slight delay in differentiation indicated by the level of developmental isoforms of troponin T. Prior to the onset of apparent myopathic change, both fast and slow skeletal muscle fibre types in mdx leg muscles also differentiated well when investigated by analysis of specific myosin heavy chain expression pattern. While the original muscle fibres in mdx leg muscles developed well, the differentiation of regenerated myotubes into both slow and distinct fast muscle fibre types, however, was markedly delayed or inhibited as indicated by several clusters of homogeneously staining fibres even at 14 weeks of age. The number of slow myosin heavy chain-positive myotubes amongst the regenerated muscle clusters was quite small even in soleus. This study thus established that while muscle fibres initially develop normally with only a slight delay in the differentiation process, the differentiation of regenerated myotubes in mdx muscles is markedly compromised and consequently delayed.

Muscle involvement in Schönlein-Henoch syndrome.

PubMed Central

Somekh, E; Fried, D; Hanukoglu, A

1983-01-01

Three patients with Schönlein-Henoch syndrome developed severe muscle pain in the legs. The pain, so severe that they were bedridden, subsided within a few days and was caused, we believe, by bleeding into the leg muscles. PMID:6651331

Reliability of panoramic ultrasound imaging in simultaneously examining muscle size and quality of the hamstring muscles in young, healthy males and females.

PubMed

Palmer, Ty B; Akehi, Kazuma; Thiele, Ryan M; Smith, Doug B; Thompson, Brennan J

2015-03-01

The purpose of this study was to examine the reliability of ultrasound (US) measures of cross-sectional area (CSA), muscle thickness (MT) and echo intensity (EI) of the hamstrings, with comparisons between males and females. In 20 healthy participants (10 males, 10 females), CSA, MT and EI were measured from panoramic US scans of the hamstrings on 2 separate days. The intra-class correlation coefficients and standard errors of measurement as a percentage of the mean for CSA, MT and EI ranged from 0.715 to 0.984 and from 3.145 to 12.541% in the males and from 0.724 to 0.977 and from 4.571 to 17.890% in the females, respectively. The males had greater CSAs and MTs and lower EIs than the females (p = 0.002-0.049), and significant relationships were observed between CSA and MT (r = 0.714-0.938, p ≤ 0.001-0.023). From an overall reliability standpoint, these findings suggest that panoramic US may be a reliable technique for examining muscle size and quality of the hamstrings in both males and females. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Ultrasound evaluation of muscle thickness changes in the external oblique, internal oblique, and transversus abdominis muscles considering the influence of posture and muscle contraction.

PubMed

Sugaya, Tomoaki; Abe, Yota; Sakamoto, Masaaki

2014-09-01

[Purpose] The aim of this study was to investigate muscle thickness changes in the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) muscles between the neutral position and trunk rotation, under a state of rest without voluntary contractions, and isometric contractions to both sides with resistance of 50% of the maximum trunk rotation strength. [Subjects] The subjects of this study were 21 healthy young men. [Methods] Muscle thickness changes in the EO, IO, and TrA in each position and state were evaluated by ultrasound. The range of motion at maximum trunk rotation and the maximum strength of trunk rotation were measured using a hand-held dynamometer. [Results] In the neutral position and at 50% trunk rotation to the right side, the thicknesses of the IO and TrA significantly increased with resistance. In both states, the thicknesses of the IO and TrA significantly increased at 50% trunk rotation to the right side. [Conclusion] The muscular contractions of the IO and TrA were stronger during ipsilateral rotation than in the neutral position and with resistance than at rest. Moreover, the muscular contraction was strongest in the resistive state during ipsilateral rotation.

A Comparison of Two Injection Locations in Obese Patients Having Lower Leg/Foot Surgery

ClinicalTrials.gov

2015-10-13

Strain of Muscle and/or Tendon of Lower Leg; Fracture of Lower Leg; Crushing Injury of Lower Leg; Fracture Malunion - Ankle and/ or Foot; Complete Tear, Ankle and/or Foot Ligament; Pathological Fracture - Ankle and/or Foot; Loose Body in Joint of Ankle and/or Foot

Fatigue-related firing of muscle nociceptors reduces voluntary activation of ipsilateral but not contralateral lower limb muscles.

PubMed

Kennedy, David S; Fitzpatrick, Siobhan C; Gandevia, Simon C; Taylor, Janet L

2015-02-15

During fatiguing upper limb exercise, maintained firing of group III/IV muscle afferents can limit voluntary drive to muscles within the same limb. It is not known if this effect occurs in the lower limb. We investigated the effects of group III/IV muscle afferent firing from fatigued ipsilateral and contralateral extensor muscles and ipsilateral flexor muscles of the knee on voluntary activation of the knee extensors. In three experiments, we examined voluntary activation of the knee extensors by measuring changes in superimposed twitches evoked by femoral nerve stimulation. Subjects attended on 2 days for each experiment. On one day a sphygmomanometer cuff occluded blood flow of the fatigued muscles to maintain firing of group III/IV muscle afferents. After a 2-min extensor contraction (experiment 1; n = 9), mean voluntary activation was lower with than without maintained ischemia (47 ± 19% vs. 87 ± 8%, respectively; P < 0.001). After a 2-min knee flexor maximal voluntary contraction (MVC) (experiment 2; n = 8), mean voluntary activation was also lower with than without ischemia (59 ± 21% vs. 79 ± 9%; P < 0.01). After the contralateral (left) MVC (experiment 3; n = 8), mean voluntary activation of the right leg was similar with or without ischemia (92 ± 6% vs. 93 ± 4%; P = 0.65). After fatiguing exercise, activity in group III/IV muscle afferents reduces voluntary activation of the fatigued muscle and nonfatigued antagonist muscles in the same leg. However, group III/IV muscle afferents from the fatigued left leg had no effect on the unfatigued right leg. This suggests that any "crossover" of central fatigue in the lower limbs is not mediated by group III/IV muscle afferents. Copyright © 2015 the American Physiological Society.

Surface electromyography and ultrasound evaluation of pelvic floor muscles in hyperandrogenic women.

PubMed

Vassimon, Flávia Ignácio Antonio; Ferreira, Cristine Homsi Jorge; Martins, Wellington Paula; Ferriani, Rui Alberto; Batista, Roberta Leopoldino de Andrade; Bo, Kari

2016-04-01

High levels of androgens increase muscle mass. Due to the characteristics of hyperandrogenism in polycystic ovary syndrome (PCOS), it is plausible that women with PCOS may have increased pelvic floor muscle (PFM) thickness and neuromuscular activity levels compared with controls. The aim of this study was to assess PFM thickness and neuromuscular activity among hyperandrogenic women with PCOS and controls. This was an observational, cross-sectional, case-control study evaluating PFM by ultrasound (US) and surface electromyography (sEMG) in nonobese women with and without PCOS. Seventy-two women were divided into two groups: PCOS (n = 33) and controls (n = 39). PFM thickness during contraction was assessed by US (Vingmed CFM 800). Pelvic floor muscle activity was assessed by sEMG (MyoTrac Infinit) during contractions at different time lengths: quick, and 8 and 60 s. Descriptive analysis, analysis of variance (ANOVA), and Student's t test were used for statistical analyses. There were no significant differences in PFM sEMG activity between PCOS and controls in any of the contractions: quick contraction (73.23 mV/ 71.56 mV; p = 0.62), 8 s (55.77 mV/ 54.17 mV; p = 0.74), and 60 s (49.26 mV/ 47.32 mV; p = 0.68), respectively. There was no difference in PFM thickness during contractions evaluated by US between PCOS and controls (12.78 mm/ 13.43 mm; p =  .48). This study did not find statistically significant differences in pelvic floor muscle thickness or in muscle activity between PCOS women and controls.

Limb muscle sound speed estimation by ultrasound computed tomography excluding receivers in bone shadow

NASA Astrophysics Data System (ADS)

Qu, Xiaolei; Azuma, Takashi; Lin, Hongxiang; Takeuchi, Hideki; Itani, Kazunori; Tamano, Satoshi; Takagi, Shu; Sakuma, Ichiro

2017-03-01

Sarcopenia is the degenerative loss of skeletal muscle ability associated with aging. One reason is the increasing of adipose ratio of muscle, which can be estimated by the speed of sound (SOS), since SOSs of muscle and adipose are different (about 7%). For SOS imaging, the conventional bent-ray method iteratively finds ray paths and corrects SOS along them by travel-time. However, the iteration is difficult to converge for soft tissue with bone inside, because of large speed variation. In this study, the bent-ray method is modified to produce SOS images for limb muscle with bone inside. The modified method includes three steps. First, travel-time is picked up by a proposed Akaike Information Criterion (AIC) with energy term (AICE) method. The energy term is employed for detecting and abandoning the transmissive wave through bone (low energy wave). It results in failed reconstruction for bone, but makes iteration convergence and gives correct SOS for skeletal muscle. Second, ray paths are traced using Fermat's principle. Finally, simultaneous algebraic reconstruction technique (SART) is employed to correct SOS along ray paths, but excluding paths with low energy wave which may pass through bone. The simulation evaluation was implemented by k-wave toolbox using a model of upper arm. As the result, SOS of muscle was 1572.0+/-7.3 m/s, closing to 1567.0 m/s in the model. For vivo evaluation, a ring transducer prototype was employed to scan the cross sections of lower arm and leg of a healthy volunteer. And the skeletal muscle SOSs were 1564.0+/-14.8 m/s and 1564.1±18.0 m/s, respectively.

Applying a pelvic corrective force induces forced use of the paretic leg and improves paretic leg EMG activities of individuals post-stroke during treadmill walking.

PubMed

Hsu, Chao-Jung; Kim, Janis; Tang, Rongnian; Roth, Elliot J; Rymer, William Z; Wu, Ming

2017-10-01

To determine whether applying a mediolateral corrective force to the pelvis during treadmill walking would enhance muscle activity of the paretic leg and improve gait symmetry in individuals with post-stroke hemiparesis. Fifteen subjects with post-stroke hemiparesis participated in this study. A customized cable-driven robotic system based over a treadmill generated a mediolateral corrective force to the pelvis toward the paretic side during early stance phase. Three different amounts of corrective force were applied. Electromyographic (EMG) activity of the paretic leg, spatiotemporal gait parameters and pelvis lateral displacement were collected. Significant increases in integrated EMG of hip abductor, medial hamstrings, soleus, rectus femoris, vastus medialis and tibialis anterior were observed when pelvic corrective force was applied, with pelvic corrective force at 9% of body weight inducing greater muscle activity than 3% or 6% of body weight. Pelvis lateral displacement was more symmetric with pelvic corrective force at 9% of body weight. Applying a mediolateral pelvic corrective force toward the paretic side may enhance muscle activity of the paretic leg and improve pelvis displacement symmetry in individuals post-stroke. Forceful weight shift to the paretic side could potentially force additional use of the paretic leg and improve the walking pattern. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Comparative analysis of ultrasound changes in the vastus lateralis muscle following myofascial release and thermotherapy: a pilot study.

PubMed

Ichikawa, Kazuna; Takei, Hitoshi; Usa, Hideyuki; Mitomo, Shoh; Ogawa, Daisuke

2015-04-01

This study aimed to compare the effects of myofascial release (MFR) and hot pack therapy (HPT) on fascial gliding and flexibility of the vastus lateralis muscle. Three treatments were applied to the left vastus lateralis muscles of each participant (12 healthy males): MFR for 4 min, superficial HPT for 10 min, and superficial HPT for 20 min. Deep fascial motion was measured by B-mode ultrasound, whereas muscle stiffness was measured by real-time elastography (RTE) and a durometer before and after the interventions. Only MFR resulted in changes in both deep fascial motion and muscle stiffness measured by RTE. Durometer-measured muscle stiffness revealed changes following both MFR and 20-min HPT but not 10-min HPT. HPT may produce only superficial effects. Because MFR improved all measured parameters, continuous stretching and pressure are probably important for improving fascial gliding and flexibility of the vastus lateralis muscle. Copyright © 2014 Elsevier Ltd. All rights reserved.

Muscle and bone follow similar temporal patterns of recovery from muscle-induced disuse due to botulinum toxin injection.

PubMed

Manske, Sarah L; Boyd, Steven K; Zernicke, Ronald F

2010-01-01

If muscle force is a primary source for triggering bone adaptation, with disuse and reloading, bone changes should follow muscle changes. We examined the timing and magnitude of changes in muscle cross-sectional area (MCSA) and bone architecture in response to muscle inactivity following botulinum toxin (BTX) injection. We hypothesized that MCSA would return to baseline levels sooner than bone properties following BTX injection. Female BALB mice (15 weeks old) were injected with 20 muL of BTX (1 U/100 g body mass, n=18) or saline (SAL, n=18) into the posterior calf musculature of one limb. The contralateral limb (CON) served as an internal control. MCSA and bone properties were assessed at baseline, 2, 4, 8, 12, and 16 weeks post-injection using in vivo micro-CT at the tibia proximal metaphysis (bone only) and diaphysis. Muscles were dissected and weighed after sacrifice. Significant GroupxLegxTime interactions indicated that the maximal decrease in MCSA (56%), proximal metaphyseal BV/TV (38%) and proximal diaphyseal Ct.Ar (7%) occurred 4 weeks after injection. There was no delay prior to bone recovery as both muscle and bone properties began to recover after this time, but MCSA and BV/TV remained 15% and 20% lower, respectively, in the BTX-injected leg than the BTX-CON leg 16 weeks post-injection. Gastrocnemius mass (primarily fast-twitch) was 14% lower in the BTX-injected leg than the SAL-injected leg, while soleus mass (primarily slow-twitch) was 15% greater in the BTX group than the SAL group. Our finding that muscle size and bone began to recover at similar times after BTX injection was unexpected. This suggested that partial weight-bearing and/or return of slow-twitch muscle activity in the BTX leg may have been sufficient to stimulate bone recovery. Alternatively, muscle function may have recovered sooner than MCSA. Our results indicated that muscle cross-sectional area, while important, may not be the primary factor associated with bone loss and recovery

Does intermittent pneumatic leg compression enhance muscle recovery after strenuous eccentric exercise?

PubMed

Cochrane, D J; Booker, H R; Mundel, T; Barnes, M J

2013-11-01

Intermittent pneumatic compression (IPC) has gained rapid popularity as a post-exercise recovery modality. Despite its widespread use and anecdotal claims for enhancing muscle recovery there is no scientific evidence to support its use. 10 healthy, active males performed a strenuous bout of eccentric exercise (3 sets of 100 repetitions) followed by IPC treatment or control performed immediately after exercise and at 24 and 48 h post-exercise. Muscular performance measurements were taken prior to exercise and 24, 48 and 72 h post-exercise and included single-leg vertical jump (VJ) and peak and average isometric [knee angle 75º] (ISO), concentric (CON) and eccentric (ECC) contractions performed at slow (30° · s⁻¹) and fast (180° · s⁻¹) velocities. Plasma creatine kinase (CK) samples were taken at pre- and post-exercise 24, 48 and 72 h. Strenuous eccentric exercise resulted in a significant decrease in peak ISO, peak and average CON (30° · s⁻¹) at 24 h compared to pre-exercise for both IPC and control, however VJ performance remained unchanged. There were no significant differences between conditions (IPC and control) or condition-time interactions for any of the contraction types (ISO, CON, ECC) or velocities (CON, ECC 30° · s⁻¹ and 180° · s⁻¹). However, CK was significantly elevated at 24 h compared to pre-exercise in both conditions (IPC and control). IPC did not attenuate muscle force loss following a bout of strenuous eccentric exercise in comparison to a control. While IPC has been used in the clinical setting to treat pathologic conditions, the parameters used to treat muscle damage following strenuous exercise in healthy participants are likely to be very different than those used to treat pathologic conditions. © Georg Thieme Verlag KG Stuttgart · New York.

Strength Training for Skeletal Muscle Endurance after Stroke

PubMed Central

Ivey, Frederick M.; Prior, Steven J.; Hafer-Macko, Charlene E.; Katzel, Leslie I.; Macko, Richard F.; Ryan, Alice S.

2018-01-01

Background and Purpose Initial studies support the use of strength training (ST) as a safe and effective intervention after stroke. Our previous work shows that relatively aggressive, higher intensity ST translates into large effect sizes for paretic and non-paretic leg muscle volume, myostatin expression, and maximum strength post-stroke. An unanswered question pertains to how our unique ST model for stroke impacts skeletal muscle endurance (SME). Thus, we now report on ST-induced adaptation in the ability to sustain isotonic muscle contraction. Methods Following screening and baseline testing, hemiparetic stroke participants were randomized to either ST or an attention-matched stretch control group (SC). Those in the ST group trained each leg individually to muscle failure (20 repetition sets, 3× per week for 3 months) on each of three pneumatic resistance machines (leg press, leg extension, and leg curl). Our primary outcome measure was SME, quantified as the number of submaximal weight leg press repetitions possible at a specified cadence. The secondary measures included one-repetition maximum strength, 6-minute walk distance (6MWD), 10-meter walk speeds, and peak aerobic capacity (VO2 peak). Results ST participants (N = 14) had significantly greater SME gains compared with SC participants (N = 16) in both the paretic (178% versus 12%, P < .01) and non-paretic legs (161% versus 12%, P < .01). These gains were accompanied by group differences for 6MWD (P < .05) and VO2 peak (P < .05). Conclusion Our ST regimen had a large impact on the capacity to sustain submaximal muscle contraction, a metric that may carry more practical significance for stroke than the often reported measures of maximum strength. PMID:27865696

Mechanical design and driving mechanism of an isokinetic functional electrical stimulation-based leg stepping trainer.

PubMed

Hamzaid, N A; Fornusek, C; Ruys, A; Davis, G M

2007-12-01

The mechanical design of a constant velocity (isokinetic) leg stepping trainer driven by functional electrical stimulation-evoked muscle contractions was the focus of this paper. The system was conceived for training the leg muscles of neurologically-impaired patients. A commercially available slider crank mechanism for elliptical stepping exercise was adapted to a motorized isokinetic driving mechanism. The exercise system permits constant-velocity pedalling at cadences of 1-60 rev x min(-1). The variable-velocity feature allows low pedalling forces for individuals with very weak leg muscles, yet provides resistance to higher pedalling effort in stronger patients. In the future, the system will be integrated with a computer-controlled neuromuscular stimulator and a feedback control unit to monitor training responses of spinal cord-injured, stroke and head injury patients.

Locomotor-Like Leg Movements Evoked by Rhythmic Arm Movements in Humans

PubMed Central

Sylos-Labini, Francesca; Ivanenko, Yuri P.; MacLellan, Michael J.; Cappellini, Germana; Poppele, Richard E.; Lacquaniti, Francesco

2014-01-01

Motion of the upper limbs is often coupled to that of the lower limbs in human bipedal locomotion. It is unclear, however, whether the functional coupling between upper and lower limbs is bi-directional, i.e. whether arm movements can affect the lumbosacral locomotor circuitry. Here we tested the effects of voluntary rhythmic arm movements on the lower limbs. Participants lay horizontally on their side with each leg suspended in an unloading exoskeleton. They moved their arms on an overhead treadmill as if they walked on their hands. Hand-walking in the antero-posterior direction resulted in significant locomotor-like movements of the legs in 58% of the participants. We further investigated quantitatively the responses in a subset of the responsive subjects. We found that the electromyographic (EMG) activity of proximal leg muscles was modulated over each cycle with a timing similar to that of normal locomotion. The frequency of kinematic and EMG oscillations in the legs typically differed from that of arm oscillations. The effect of hand-walking was direction specific since medio-lateral arm movements did not evoke appreciably leg air-stepping. Using externally imposed trunk movements and biomechanical modelling, we ruled out that the leg movements associated with hand-walking were mainly due to the mechanical transmission of trunk oscillations. EMG activity in hamstring muscles associated with hand-walking often continued when the leg movements were transiently blocked by the experimenter or following the termination of arm movements. The present results reinforce the idea that there exists a functional neural coupling between arm and legs. PMID:24608249

Thigh muscle and subcutaneous tissue thickness measured using ultrasound imaging in older females living in extended care: a preliminary study.

PubMed

Welch, Daniella; Ndanyo, Laetitia Sungu; Brown, Simon; Agyapong-Badu, Sandra; Warner, Martin; Stokes, Maria; Samuel, Dinesh

2018-05-01

Thigh tissue thickness has not been examined in older females living in extended care in UK as an indicator of musculoskeletal health. This study examined the feasibility of using ultrasound imaging to measure the thickness of superficial (fat) and deep layers (muscle) of the thigh in older females living in extended care. In ten older females in extended care (aged 80-98 years, mean 88 ± 6.8; body mass: 56.5 ± 12.6 kg) images of the anterior thigh (dominant) were taken in supine using B-mode ultrasound imaging. Superficial and deep layers were measured and percentage thickness was calculated. Independent t tests compared data from those in extended care to ten sedentary females living independently (aged 80-90 years, mean 84 ± 3.6; body mass: 61.6 ± 10.0 kg). Thickness of the superficial layers was not significantly different between the two groups (CI -0.017 to 0.815, p = 0.059). However, those living in extended care had greater (p < 0.001) muscle thickness (mean 2.75 ± 0.48 cm) than those living independently (mean 1.83 ± 0.3 cm), which was similarly significant when normalised for body mass (extended care 0.51 ± 0.16; independent living 0.30 ± 0.06). These novel findings showed it is feasible to use ultrasound to measure muscles in older females in extended care and that muscle thickness was larger than in those living independently. The reason for the difference seen between groups would need to be confirmed by a larger study that also examined factors related to risk of sarcopenia and frailty, such as nutrition and physical activity levels.

Differences in kinematics and electromyographic activity between men and women during the single-legged squat.

PubMed

Zeller, Brian L; McCrory, Jean L; Kibler, W Ben; Uhl, Timothy L

2003-01-01

Numerous factors have been identified as potentially increasing the risk of anterior cruciate ligament injury in the female athlete. However, differences between the sexes in lower extremity coordination, particularly hip control, are only minimally understood. There is no difference in kinematic or electromyographic data during the single-legged squat between men and women. Descriptive comparison study. We kinematically and electromyographically analyzed the single-legged squat in 18 intercollegiate athletes (9 male, 9 female). Subjects performed five single-legged squats on their dominant leg, lowering themselves as far as possible and then returning to a standing position without losing balance. Women demonstrated significantly more ankle dorsiflexion, ankle pronation, hip adduction, hip flexion, hip external rotation, and less trunk lateral flexion than men. These factors were associated with a decreased ability of the women to maintain a varus knee position during the squat as compared with the men. Analysis of all eight tested muscles demonstrated that women had greater muscle activation compared with men. When each muscle was analyzed separately, the rectus femoris muscle activation was found to be statistically greater in women in both the area under the linear envelope and maximal activation data. Under a physiologic load in a position commonly assumed in sports, women tend to position their entire lower extremity and activate muscles in a manner that could increase strain on the anterior cruciate ligament.

Central and peripheral hemodynamics in exercising humans: leg vs arm exercise.

PubMed

Calbet, J A L; González-Alonso, J; Helge, J W; Søndergaard, H; Munch-Andersen, T; Saltin, B; Boushel, R

2015-12-01

In humans, arm exercise is known to elicit larger increases in arterial blood pressure (BP) than leg exercise. However, the precise regulation of regional vascular conductances (VC) for the distribution of cardiac output with exercise intensity remains unknown. Hemodynamic responses were assessed during incremental upright arm cranking (AC) and leg pedalling (LP) to exhaustion (Wmax) in nine males. Systemic VC, peak cardiac output (Qpeak) (indocyanine green) and stroke volume (SV) were 18%, 23%, and 20% lower during AC than LP. The mean BP, the rate-pressure product and the associated myocardial oxygen demand were 22%, 12%, and 14% higher, respectively, during maximal AC than LP. Trunk VC was reduced to similar values at Wmax. At Wmax, muscle mass-normalized VC and fractional O2 extraction were lower in the arm than the leg muscles. However, this was compensated for during AC by raising perfusion pressure to increase O2 delivery, allowing a similar peak VO2 per kg of muscle mass in both extremities. In summary, despite a lower Qpeak during arm cranking the cardiovascular strain is much higher than during leg pedalling. The adjustments of regional conductances during incremental exercise to exhaustion depend mostly on the relative intensity of exercise and are limb-specific. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Leg and trunk muscle coordination and postural sway during increasingly difficult standing balance tasks in young and older adults.

PubMed

Donath, Lars; Kurz, Eduard; Roth, Ralf; Zahner, Lukas; Faude, Oliver

2016-09-01

Ageing impairs body balance and increases older adults' fall risk. Balance training can improve intrinsic fall risk factors. However, age comparisons of muscle activity responses during balance tasks are lacking. This study investigated relative muscle activity, muscle coordination and postural sway during various recommended static balance training tasks. Muscle activity (%MVC), amplitude ratios (AR) and co-activity (CAI) were determined during standing tasks for 30s (1: double limb stance on a foam surface, eyes open; 2: double limb stance on firm ground, eyes closed; 3: double limb stance, feet in step position on a foam surface, eyes open; 4: double limb stance, feet in step position on firm ground, eyes closed; 5: single limb stance on firm ground, eyes open) in 20 healthy young adults (24±2 y) and 20 older adults (73±6 y). Surface electromyography (SEMG) was applied (SENIAM guidelines) to ankle (tibialis anterior, soleus, medial gastrocnemius, peroneus longus) and thigh (vastus lateralis, vastus medialis, biceps femoris, semitendinosus) muscles (non-dominant leg). Electrodes over trunk (multifidus and internal oblique) muscles were applied bilaterally. Two- to six-fold higher levels of relative muscle activity were found in older adults for ankle (0.0002muscles. Co-activation was elevated in young adults for the trunk (0.001muscle coordination patterns during all stance conditions at the ankle (0.06<ηp(2)<0.28) and the trunk (0.14<ηp(2)<0.23). Older adults had higher electrophysiological costs for all stance conditions. Muscle coordination showed inverse activity patterns at the ankle and trunk. Optimal balance and strength training programs should take into account age-specific alterations in muscle activity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Change in skeletal muscle stiffness after running competition is dependent on both running distance and recovery time: a pilot study.

PubMed

Sadeghi, Seyedali; Newman, Cassidy; Cortes, Daniel H

2018-01-01

Long-distance running competitions impose a large amount of mechanical loading and strain leading to muscle edema and delayed onset muscle soreness (DOMS). Damage to various muscle fibers, metabolic impairments and fatigue have been linked to explain how DOMS impairs muscle function. Disruptions of muscle fiber during DOMS exacerbated by exercise have been shown to change muscle mechanical properties. The objective of this study is to quantify changes in mechanical properties of different muscles in the thigh and lower leg as function of running distance and time after competition. A custom implementation of Focused Comb-Push Ultrasound Shear Elastography (F-CUSE) method was used to evaluate shear modulus in runners before and after a race. Twenty-two healthy individuals (age: 23 ± 5 years) were recruited using convenience sampling and split into three race categories: short distance (nine subjects, 3-5 miles), middle distance (10 subjects, 10-13 miles), and long distance (three subjects, 26+ miles). Shear Wave Elastography (SWE) measurements were taken on both legs of each subject on the rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), soleus, lateral gastrocnemius (LG), medial gastrocnemius (MG), biceps femoris (BF) and semitendinosus (ST) muscles. For statistical analyses, a linear mixed model was used, with recovery time and running distance as fixed variables, while shear modulus was used as the dependent variable. Recovery time had a significant effect on the soleus ( p  = 0.05), while running distance had considerable effect on the biceps femoris ( p  = 0.02), vastus lateralis ( p  < 0.01) and semitendinosus muscles ( p  = 0.02). Sixty-seven percent of muscles exhibited a decreasing stiffness trend from before competition to immediately after competition. The preliminary results suggest that SWE could potentially be used to quantify changes of muscle mechanical properties as a way for measuring recovery procedures for runners.

The effects of a 4-week static stretching programme on the individual muscles comprising the hamstrings.

PubMed

Ichihashi, Noriaki; Umegaki, Hiroki; Ikezoe, Tome; Nakamura, Masatoshi; Nishishita, Satoru; Fujita, Kosuke; Umehara, Jun; Nakao, Sayaka; Ibuki, Satoko

2016-12-01

The aims of this study were to investigate the effects of a 4-week intervention of static stretching (SS) on muscle hardness of the semitendinosus (ST), semimembranosus (SM) and biceps femoris (BF) muscles. Shear elastic modulus was measured by using ultrasound shear wave elastography as the index of muscle hardness. Thirty healthy men (age 22.7 ± 2.2 years) volunteered for this study and were randomly assigned to the SS intervention group (n = 15) or the control group (n = 15). Participants in the SS intervention group received a 4-week stretch intervention for the hamstrings of their dominant leg. Shear elastic moduli of the hamstrings were measured at initial evaluation and after 4 weeks in both groups at a determined angle. In all muscles, the shear elastic modulus decreased significantly after SS intervention. The percentage change in the shear elastic modulus from the value at initial evaluation to after 4 weeks intervention was greatest in the SM. These results suggest that SS intervention has chronic effects on reducing hardness of the hamstring muscle components, especially the SM muscle.

Quantitative MRI and strength measurements in the assessment of muscle quality in Duchenne muscular dystrophy.

PubMed

Wokke, B H; van den Bergen, J C; Versluis, M J; Niks, E H; Milles, J; Webb, A G; van Zwet, E W; Aartsma-Rus, A; Verschuuren, J J; Kan, H E

2014-05-01

The purpose of this study was to assess leg muscle quality and give a detailed description of leg muscle involvement in a series of Duchenne muscular dystrophy patients using quantitative MRI and strength measurements. Fatty infiltration, as well as total and contractile (not fatty infiltrated) cross sectional areas of various leg muscles were determined in 16 Duchenne patients and 11 controls (aged 8-15). To determine specific muscle strength, four leg muscle groups (quadriceps femoris, hamstrings, anterior tibialis and triceps surae) were measured and related to the amount of contractile tissue. In patients, the quadriceps femoris showed decreased total and contractile cross sectional area, attributable to muscle atrophy. The total, but not the contractile, cross sectional area of the triceps surae was increased in patients, corresponding to hypertrophy. Specific strength decreased in all four muscle groups of Duchenne patients, indicating reduced muscle quality. This suggests that muscle hypertrophy and fatty infiltration are two distinct pathological processes, differing between muscle groups. Additionally, the quality of remaining muscle fibers is severely reduced in the legs of Duchenne patients. The combination of quantitative MRI and quantitative muscle testing could be a valuable outcome parameter in longitudinal studies and in the follow-up of therapeutic effects. Copyright © 2014 Elsevier B.V. All rights reserved.

No differential effects of divergent isocaloric supplements on signaling for muscle protein turnover during recovery from muscle-damaging eccentric exercise.

PubMed

Rahbek, Stine Klejs; Farup, Jean; de Paoli, Frank; Vissing, Kristian

2015-04-01

Unaccustomed high-intensity eccentric exercise (ECC) can provoke muscle damage including several days of muscle force loss. Post-exercise dietary supplementation may provide a strategy to accelerate rate of force regain by affecting mechanisms related to muscle protein turnover. The aim of the current study was to investigate if protein signaling mechanisms involved in muscle protein turnover would be differentially affected by supplementation with either whey protein hydrolysate and carbohydrate (WPH+CHO) versus isocaloric carbohydrate (CHO) after muscle-damaging ECC. Twenty-four young healthy participants received either WPH+CHO (n = 12) or CHO supplements (n = 12) during post-exercise recovery from 150 maximal unilateral eccentric contractions. Prior to, at 3 h and at 24, 48, 96 and/or 168 h post-exercise, muscle strength, muscle soreness, and Akt-mTOR and FOXO signaling proteins, were measured in an ECC exercising leg and in the contralateral non-exercise control leg (CON). After ECC, muscle force decreased by 23-27 % at 24 h post-exercise, which was followed by gradual, although not full recovery at 168 h post-exercise, with no differences between supplement groups. Phosphorylation of mTOR, p70S6K and rpS6 increased and phosphorylation of FOXO1 and FOXO3 decreased in the ECC leg, with no differences between supplement groups. Phosphorylation changes were also observed for rpS6, FOXO1 and FOXO3a in the CON leg, suggesting occurrence of remote tissue effects. In conclusion, divergent dietary supplementation types did not produce differences in signaling for muscle turnover during recovery from muscle-damaging exercise.

Trunk, pelvis, hip, and knee kinematics, hip strength, and gluteal muscle activation during a single-leg squat in males and females with and without patellofemoral pain syndrome.

PubMed

Nakagawa, Theresa H; Moriya, Erika T U; Maciel, Carlos D; Serrão, Fábio V

2012-06-01

Controlled laboratory study using a cross-sectional design. To determine whether there are any differences between the sexes in trunk, pelvis, hip, and knee kinematics, hip strength, and gluteal muscle activation during the performance of a single-leg squat in individuals with patellofemoral pain syndrome (PFPS) and control participants. Though there is a greater incidence of PFPS in females, PFPS is also quite common in males. Trunk kinematics may affect hip and knee function; however, there is a lack of studies of the influence of the trunk in individuals with PFPS. Eighty subjects were distributed into 4 groups: females with PFPS, female controls, males with PFPS, and male controls. Trunk, pelvis, hip, and knee kinematics and gluteal muscle activation were evaluated during a single-leg squat. Hip abduction and external rotation eccentric strength was measured on an isokinetic dynamometer. Group differences were assessed using a 2-way multivariate analysis of variance (sex by PFPS status). Compared to controls, subjects with PFPS had greater ipsilateral trunk lean (mean ± SD, 9.3° ± 5.3° versus 6.7° ± 3.0°; P = .012), contralateral pelvic drop (10.3° ± 4.7° versus 7.4° ± 3.8°; P = .003), hip adduction (14.8° ± 7.8° versus 10.8° ± 5.6°; P<.0001), and knee abduction (9.2° ± 5.0° versus 5.8° ± 3.4°; P<.0001) when performing a single-leg squat. Subjects with PFPS also had 18% less hip abduction and 17% less hip external rotation strength. Compared to female controls, females with PFPS had more hip internal rotation (P<.05) and less muscle activation of the gluteus medius (P = .017) during the single-leg squat. Despite many similarities in findings for males and females with PFPS, there may be specific sex differences that warrant consideration in future studies and when clinically evaluating and treating females with PFPS.

Human hopping on damped surfaces: strategies for adjusting leg mechanics.

PubMed

Moritz, Chet T; Farley, Claire T

2003-08-22

Fast-moving legged animals bounce along the ground with spring-like legs and agilely traverse variable terrain. Previous research has shown that hopping and running humans maintain the same bouncing movement of the body's centre of mass on a range of elastic surfaces by adjusting their spring-like legs to exactly offset changes in surface stiffness. This study investigated human hopping on damped surfaces that dissipated up to 72% of the hopper's mechanical energy. On these surfaces, the legs did not act like pure springs. Leg muscles performed up to 24-fold more net work to replace the energy lost by the damped surface. However, considering the leg and surface together, the combination appeared to behave like a constant stiffness spring on all damped surfaces. By conserving the mechanics of the leg-surface combination regardless of surface damping, hoppers also conserved centre-of-mass motions. Thus, the normal bouncing movements of the centre of mass in hopping are not always a direct result of spring-like leg behaviour. Conserving the trajectory of the centre of mass by maintaining spring-like mechanics of the leg-surface combination may be an important control strategy for fast-legged locomotion on variable terrain.

Lower extremity muscle activation during baseball pitching.

PubMed

Campbell, Brian M; Stodden, David F; Nixon, Megan K

2010-04-01

The purpose of this study was to investigate muscle activation levels of select lower extremity muscles during the pitching motion. Bilateral surface electromyography data on 5 lower extremity muscles (biceps femoris, rectus femoris, gluteus maximus, vastus medialis, and gastrocnemius) were collected on 11 highly skilled baseball pitchers and compared with individual maximal voluntary isometric contraction (MVIC) data. The pitching motion was divided into 4 distinct phases: phase 1, initiation of pitching motion to maximum stride leg knee height; phase 2, maximum stride leg knee height to stride foot contact (SFC); phase 3, SFC to ball release; and phase 4, ball release to 0.5 seconds after ball release (follow-through). Results indicated that trail leg musculature elicited moderate to high activity levels during phases 2 and 3 (38-172% of MVIC). Muscle activity levels of the stride leg were moderate to high during phases 2-4 (23-170% of MVIC). These data indicate a high demand for lower extremity strength and endurance. Specifically, coaches should incorporate unilateral and bilateral lower extremity exercises for strength improvement or maintenance and to facilitate dynamic stabilization of the lower extremities during the pitching motion.

Muscle size, quality, and body composition: characteristics of division I cross-country runners.

PubMed

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

2015-02-01

The primary purpose of this study was to identify the relationship between muscle cross-sectional area (mCSA), echo intensity (EI), and body composition of Division I cross-country runners. The secondary purpose was to examine differences in these variables in athletes stratified based on stress-fracture (SFx) history. Thirty-six athletes were stratified based on sex and SFx history. A panoramic scan vastus lateralis was performed using a GE Logiq-e B-mode ultrasound. Echo intensity and mCSA were determined from the scan using a grayscale imaging software (ImageJ). Body composition measures were determined using dual-energy x-ray absorptiometry. For females, mCSA was significantly correlated with left leg lean mass (LM; R = 0.54) and EI (R = -0.57). Lean mass was significantly correlated with bone mineral density (BMD; R = 0.58) and bone mineral content (BMC; R = 0.56), whereas BMC was also correlated with leg LM (R = 0.72). For males, mCSA was significantly correlated with leg LM (R = 0.66), BMD (R = 0.50), and BMC (R = 0.54). Leg LM was significantly correlated with BMD (R = 0.53) and BMC (R = 0.77). Personal best times for males were significantly correlated with fat mass (R = 0.489) and %fat (R = 0.556) for the 10- and 5-km races, respectively. Female and male athletes with a history of SFx were not significantly different across any variables when compared with athletes with no history. These correlations suggest that more muscle mass may associate with higher BMD and BMC for stronger bone structure. Modifications in training strategies to include heavy resistance training and plyometrics may be advantageous for preventing risk factors associated with SFx reoccurrence.

Sagittal plane bending moments acting on the lower leg during running.

PubMed

Haris Phuah, Affendi; Schache, Anthony G; Crossley, Kay M; Wrigley, Tim V; Creaby, Mark W

2010-02-01

Sagittal bending moments acting on the lower leg during running may play a role in tibial stress fracture development. The purpose of this study was to evaluate these moments at nine equidistant points along the length of the lower leg (10% point-90% point) during running. Kinematic and ground reaction force data were collected for 20 male runners, who each performed 10 running trials. Inverse dynamics and musculoskeletal modelling techniques were used to estimate sagittal bending moments due to reaction forces and muscle contraction. The muscle moment was typically positive during stance, except at the most proximal location (10% point) on the lower leg. The reaction moment was predominantly negative throughout stance and greater in magnitude than the muscle moment. Hence, the net sagittal bending moment acting on the lower leg was principally negative (indicating tensile loads on the posterior tibia). Peak moments typically occurred around mid-stance, and were greater in magnitude at the distal, compared with proximal, lower leg. For example, the peak reaction moment at the most distal point was -9.61+ or - 2.07%Bw.Ht., and -2.73 + or - 1.18%Bw.Ht. at the most proximal point. These data suggest that tensile loads on the posterior tibia are likely to be higher toward the distal end of the bone. This finding may explain the higher incidence of stress fracture in the distal aspect of the tibia, observed by some authors. Stress fracture susceptibility will also be influenced by bone strength and this should also be accounted for in future studies. Copyright 2009 Elsevier B.V. All rights reserved.

Exercise intensity and muscle hypertrophy in blood flow-restricted limbs and non-restricted muscles: a brief review.

PubMed

Abe, Takashi; Loenneke, Jeremy P; Fahs, Christopher A; Rossow, Lindy M; Thiebaud, Robert S; Bemben, Michael G

2012-07-01

Although evidence for high-intensity resistance training-induced muscle hypertrophy has accumulated over the last several decades, the basic concept of the training can be traced back to ancient Greece: Milo of Croton lifted a bull-calf daily until it was fully grown, which would be known today as progressive overload. Now, in the 21st century, different types of training are being tested and studied, such as low-intensity exercise combined with arterial as well as venous blood flow restriction (BFR) to/from the working muscles. Because BFR training requires the use of a cuff that is placed at the proximal ends of the arms and/or legs, the BFR is only applicable to limb muscles. Consequently, most previous BFR training studies have focused on the physiological adaptations of BFR limb muscles. Muscle adaptations in non-BFR muscles of the hip and trunk are lesser known. Recent studies that have reported both limb and trunk muscle adaptations following BFR exercise training suggest that low-intensity (20-30% of 1RM) resistance training combined with BFR elicits muscle hypertrophy in both BFR limb and non-BFR muscles. However, the combination of leg muscle BFR with walk training elicits muscle hypertrophy only in the BFR leg muscles. In contrast to resistance exercise with BFR, the exercise intensity may be too low during BFR walk training to cause muscle hypertrophy in the non-BFR gluteus maximus and other trunk muscles. Other mechanisms including hypoxia, local and systemic growth factors and muscle cell swelling may also potentially affect the hypertrophic response of non-BFR muscles to BFR resistance exercise. © 2012 The Authors Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

A new biarticular actuator design facilitates control of leg function in BioBiped3.

PubMed

Sharbafi, Maziar Ahmad; Rode, Christian; Kurowski, Stefan; Scholz, Dorian; Möckel, Rico; Radkhah, Katayon; Zhao, Guoping; Rashty, Aida Mohammadinejad; Stryk, Oskar von; Seyfarth, Andre

2016-07-01

Bioinspired legged locomotion comprises different aspects, such as (i) benefiting from reduced complexity control approaches as observed in humans/animals, (ii) combining embodiment with the controllers and (iii) reflecting neural control mechanisms. One of the most important lessons learned from nature is the significant role of compliance in simplifying control, enhancing energy efficiency and robustness against perturbations for legged locomotion. In this research, we investigate how body morphology in combination with actuator design may facilitate motor control of leg function. Inspired by the human leg muscular system, we show that biarticular muscles have a key role in balancing the upper body, joint coordination and swing leg control. Appropriate adjustment of biarticular spring rest length and stiffness can simplify the control and also reduce energy consumption. In order to test these findings, the BioBiped3 robot was developed as a new version of BioBiped series of biologically inspired, compliant musculoskeletal robots. In this robot, three-segmented legs actuated by mono- and biarticular series elastic actuators mimic the nine major human leg muscle groups. With the new biarticular actuators in BioBiped3, novel simplified control concepts for postural balance and for joint coordination in rebounding movements (drop jumps) were demonstrated and approved.

Influence of inward pressure of the transducer on lateral abdominal muscle thickness during ultrasound imaging.

PubMed

Ishida, Hiroshi; Watanabe, Sususmu

2012-09-01

Controlled laboratory study, technical note. The purpose of this study was to quantify changes in the thickness of the transversus abdominis, internal oblique, and external oblique muscles induced by different inward pressures of the transducer during ultrasound imaging (USI). USI of the lateral abdominal muscles is increasingly used in managing musculoskeletal dysfunction. However, to the best of our knowledge, no study has evaluated the influence of different inward pressures of the transducer on the lateral abdominal muscle thickness during USI. Thirty healthy male volunteers participated in this study. The thickness of the transversus abdominis, internal oblique, and external oblique muscles was measured with USI by the same rater in 4 conditions of inward pressures of 0.5, 1.0, 2.0, and 4.0 N. Intraclass correlation coefficients (ICC1,1), with 95% confidence intervals, were calculated, and a repeated-measures analysis of variance was used to assess the influence of inward pressure on the thickness of the lateral abdominal muscles. The thickness of the transversus abdominis, internal oblique, and external oblique muscles was significantly different among the 4 conditions (P<.038). The mean difference between the 0.5-N and 4.0-N conditions was greater than the minimal detectable change of the 0.5-N condition in the lateral abdominal muscles. The difference in magnitude produced by the forces under different conditions was meaningful. When using a technique that involves a handheld transducer, the examiner should attempt to maintain consistent inward pressure of the transducer during USI to quantify the thickness of lateral abdominal muscles. J Orthop Sports Phys Ther 2012;42(9):815-818, Epub 19 April 2012. doi:10.2519/jospt.2012.4064.

Optimizing the Distribution of Leg Muscles for Vertical Jumping

PubMed Central

Wong, Jeremy D.; Bobbert, Maarten F.; van Soest, Arthur J.; Gribble, Paul L.; Kistemaker, Dinant A.

2016-01-01

A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas—which determine the maximum force deliverable by the muscles—constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of the skeletal

The tymbal muscle of cicada has flight muscle-type sarcomeric architecture and protein expression.

PubMed

Iwamoto, Hiroyuki

2017-01-01

The structural and biochemical features of the tymbal (sound-producing) muscle of cicadas were studied by X-ray diffraction and immunochemistry, and compared with those of flight muscles from the same species. The X-ray diffraction pattern of the tymbal muscle was very similar to that of the dorsal longitudinal flight muscle: In both muscles, the 2,0 equatorial reflection is much more intense than the 1,1, indicating that both muscles have a flight muscle-type myofilament lattice. In rigor, the first myosin/actin layer line reflection was finely lattice-sampled, indicating that the contractile proteins are arranged with a crystalline regularity as in asynchronous flight muscles. In contrast, the diffraction pattern from the tensor muscle, which modulates the sound by stressing the tymbal, did not show signs of such high regularity or flight muscle-type filament lattice. Electrophoretic patterns of myofibrillar proteins were also very similar in the tymbal muscle and flight muscles, but distinct from those from the tensor or leg muscles. The antibody raised against the flight muscle-specific troponin-I isoform reacted with an 80-kDa band from both tymbal and flight muscles, but with none of the bands from the tensor or leg muscles. The close similarities of the structural and biochemical profiles between the tymbal and the flight muscles suggest the possibility that a set of flight muscle-specific proteins is diverted to the tymbal muscle to meet its demand for fast, repetitive contractions.

Gender differences in rotation of the shank during single-legged drop landing and its relation to rotational muscle strength of the knee.

PubMed

Kiriyama, Shinya; Sato, Haruhiko; Takahira, Naonobu

2009-01-01

Increased shank rotation during landing has been considered to be one of the factors for noncontact anterior cruciate ligament injuries in female athletes. There have been no known gender differences in rotational knee muscle strength, which is expected to inhibit exaggerated shank rotation. Women have less knee external rotator strength than do men. Lower external rotator strength is associated with increased internal shank rotation at the time of landing. Controlled laboratory study. One hundred sixty-nine healthy young subjects (81 female and 88 male; age, 17.0 +/- 1.0 years) volunteered to participate in this study. The subjects performed single-legged drop landings from a 20-cm height. Femoral and shank kinematics were measured using a 3D optoelectronic tracking system during the drop landings, and then the joint angles around the knee (flexion/extension, valgus/varus, and internal/external rotation) were calculated. The maximal isometric rotational muscle strength of the knee was measured at 30 degrees of knee flexion in a supine position using a dynamometer. The female subjects had significantly less external shank rotation strength than did the male subjects (P < .001). Female subjects also exhibited significantly greater peak shank internal rotation angles than did males during landing (P < .05). Moderate but significant association was found between the maximum shank external rotation strength and the peak shank internal rotation angle during landing (r = -0.322, P < .01). Female subjects tended to have poor shank external rotator strength. This may lead to large shank internal rotation movement during the single-legged drop landing. Improving strength training of the external rotator muscle may help decrease the rates of anterior cruciate ligament injury in female athletes.

Asymmetry of quadriceps muscle oxygenation during elite short-track speed skating.

PubMed

Hesford, Catherine Mary; Laing, Stewart J; Cardinale, Marco; Cooper, Chris E

2012-03-01

It has been suggested that, because of the low sitting position in short-track speed skating, muscle blood flow is restricted, leading to decreases in tissue oxygenation. Therefore, wearable wireless-enabled near-infrared spectroscopy (NIRS) technology was used to monitor changes in quadriceps muscle blood volume and oxygenation during a 500-m race simulation in short-track speed skaters. Six elite skaters, all of Olympic standard (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm), were studied. Subjects completed a 500-m race simulation time trial (TT). Whole-body oxygen consumption was simultaneously measured with muscle oxygenation in right and left vastus lateralis as measured by NIRS. Mean time for race completion was 44.8 ± 0.4 s. VO2 peaked 20 s into the race. In contrast, muscle tissue oxygen saturation (TSI%) decreased and plateaued after 8 s. Linear regression analysis showed that right leg TSI% remained constant throughout the rest of the TT (slope value = 0.01), whereas left leg TSI% increased steadily (slope value = 0.16), leading to a significant asymmetry (P < 0.05) in the final lap. Total muscle blood volume decreased equally in both legs at the start of the simulation. However, during subsequent laps, there was a strong asymmetry during cornering; when skaters traveled solely on the right leg, there was a decrease in its muscle blood volume, whereas an increase was seen in the left leg. NIRS was shown to be a viable tool for wireless monitoring of muscle oxygenation. The asymmetry in muscle desaturation observed on the two legs in short-track speed skating has implications for training and performance.

Markedly Enhanced Skeletal Muscle Transfection Achieved by the Ultrasound-Targeted Delivery of Non-Viral Gene Nanocarriers with Microbubbles

PubMed Central

Burke, Caitlin W.; Suk, Jung Soo; Kim, Anthony J.; Hsiang, Yu-Han J.; Klibanov, Alexander L.; Hanes, Justin; Price, Richard J.

2012-01-01

Our goal was to enhance ultrasound (US)-targeted skeletal muscle transfection through the use of poly(ethyleneglycol) (PEG)/polyethylenimine (PEI) nanocomplex gene carriers and adjustments to US and microbubble (MB) parameters. C57BL/6 mice received an intravenous infusion of MBs and either “naked” luciferase plasmid or luciferase plasmid condensed in PEG/PEI nanocomplexes. Pulsed ultrasound (1MHz; 0.6 MPa or 0.8 MPa) was applied to the right hindlimb for 12 mins. Luciferase activity in both hindlimbs was assessed at 3, 5, 7, and 10 days post-treatment by bioluminescent imaging. When targeted to hindlimb using unsorted MBs and 0.6 MPa US, 7 days after treatment, we observed a >60-fold increase in luciferase activity in PEG/PEI nanocomplex treated muscles over muscles treated with “naked” plasmid DNA. Luciferase activity was consistently greater after treatment with PEG/PEI nanocomplexes at 0.6 MPa as compared to 0.8 MPa. The combination of small diameter MBs and 0.6 MPa US also resulted in significantly greater gene expression when compared to concentration matched intramuscular injections, a control condition in which considerably more PEG/PEI nanocomplexes were present in tissue. This result suggests that, in addition to facilitating PEG/PEI nanocomplex delivery from the bloodstream to tissue, US enhances transfection via one or more secondary mechanisms, including increased cellular uptake and/or trafficking to the nucleus of PEG/PEI nanocomplexes. We conclude that PEG/PEI nanocomplexes may be used to markedly enhance the amplitude of US-MB-targeted skeletal muscle transfection and that activating “small” MBs with a moderate level (0.6 MPa) of acoustic pressure can further enhance these effects. PMID:22800583

Human hopping on damped surfaces: strategies for adjusting leg mechanics.

PubMed Central

Moritz, Chet T; Farley, Claire T

2003-01-01

Fast-moving legged animals bounce along the ground with spring-like legs and agilely traverse variable terrain. Previous research has shown that hopping and running humans maintain the same bouncing movement of the body's centre of mass on a range of elastic surfaces by adjusting their spring-like legs to exactly offset changes in surface stiffness. This study investigated human hopping on damped surfaces that dissipated up to 72% of the hopper's mechanical energy. On these surfaces, the legs did not act like pure springs. Leg muscles performed up to 24-fold more net work to replace the energy lost by the damped surface. However, considering the leg and surface together, the combination appeared to behave like a constant stiffness spring on all damped surfaces. By conserving the mechanics of the leg-surface combination regardless of surface damping, hoppers also conserved centre-of-mass motions. Thus, the normal bouncing movements of the centre of mass in hopping are not always a direct result of spring-like leg behaviour. Conserving the trajectory of the centre of mass by maintaining spring-like mechanics of the leg-surface combination may be an important control strategy for fast-legged locomotion on variable terrain. PMID:12965003

2pBAb5. Validation of three-dimensional strain tracking by volumetric ultrasound image correlation in a pubovisceral muscle model

PubMed Central

Nagle, Anna S.; Nageswaren, Ashok R.; Haridas, Balakrishna; Mast, T. D.

2014-01-01

Little is understood about the biomechanical changes leading to pelvic floor disorders such as stress urinary incontinence. In order to measure regional biomechanical properties of the pelvic floor muscles in vivo, a three dimensional (3D) strain tracking technique employing correlation of volumetric ultrasound images has been implemented. In this technique, local 3D displacements are determined as a function of applied stress and then converted to strain maps. To validate this approach, an in vitro model of the pubovisceral muscle, with a hemispherical indenter emulating the downward stress caused by intra-abdominal pressure, was constructed. Volumetric B-scan images were recorded as a function of indenter displacement while muscle strain was measured independently by a sonomicrometry system (Sonometrics). Local strains were computed by ultrasound image correlation and compared with sonomicrometry-measured strains to assess strain tracking accuracy. Image correlation by maximizing an exponential likelihood function was found more reliable than the Pearson correlation coefficient. Strain accuracy was dependent on sizes of the subvolumes used for image correlation, relative to characteristic speckle length scales of the images. Decorrelation of echo signals was mapped as a function of indenter displacement and local tissue orientation. Strain measurement accuracy was weakly related to local echo decorrelation. PMID:24900165

Leg stiffness and stride frequency in human running.

PubMed

Farley, C T; González, O

1996-02-01

When humans and other mammals run, the body's complex system of muscle, tendon and ligament springs behaves like a single linear spring ('leg spring'). A simple spring-mass model, consisting of a single linear leg spring and a mass equivalent to the animal's mass, has been shown to describe the mechanics of running remarkably well. Force platform measurements from running animals, including humans, have shown that the stiffness of the leg spring remains nearly the same at all speeds and that the spring-mass system is adjusted for higher speeds by increasing the angle swept by the leg spring. The goal of the present study is to determine the relative importance of changes to the leg spring stiffness and the angle swept by the leg spring when humans alter their stride frequency at a given running speed. Human subjects ran on treadmill-mounted force platform at 2.5ms-1 while using a range of stride frequencies from 26% below to 36% above the preferred stride frequency. Force platform measurements revealed that the stiffness of the leg spring increased by 2.3-fold from 7.0 to 16.3 kNm-1 between the lowest and highest stride frequencies. The angle swept by the leg spring decreased at higher stride frequencies, partially offsetting the effect of the increased leg spring stiffness on the mechanical behavior of the spring-mass system. We conclude that the most important adjustment to the body's spring system to accommodate higher stride frequencies is that leg spring becomes stiffer.

Rehabilitative ultrasound imaging of the supraspinatus muscle: Intra- and interrater reliability of thickness and cross-sectional area.

PubMed

Schneebeli, Alessandro; Egloff, Michele; Giampietro, Amelia; Clijsen, Ron; Barbero, Marco

2014-04-01

To examine intra- and interrater reliability of thickness and cross-sectional area (CSA) measurements of the supraspinatus muscle using rehabilitative ultrasound imaging (RUSI). Two physical therapists acquired b-mode images of the supraspinatus muscles in twenty-five healthy subjects. Thickness and CSA were measured. Intra- and interrater reliability were examined. Intrarater reliability for thickness was high, (ICC1.1 0.91) for rater 1 and (ICC1.1 0.92) for rater 2. Intrarater reliability for CSA was also high, (ICC1.1 0.90) for rater 1 and (ICC1.1 0.85) for rater 2. Interrater reliability for the thickness was high, (ICC3.1 0.86). For CSA, interrater reliability was moderate, (ICC3.1 0.70). Supraspinatus muscle thickness and CSA can be reliably measured by physical therapists in healthy subjects. These findings confirm that RUSI has an interesting potential for physiotherapy clinical practice, especially to assess morphometric changes in skeletal muscles. Further research is needed in subjects with shoulder disorders. Copyright © 2013 Elsevier Ltd. All rights reserved.

GABAergic inhibition of leg motoneurons is required for normal walking behavior in freely moving Drosophila

PubMed Central

Gowda, Swetha B. M.; Paranjpe, Pushkar D.; Reddy, O. Venkateswara; Thiagarajan, Devasena; Palliyil, Sudhir; Reichert, Heinrich

2018-01-01

Walking is a complex rhythmic locomotor behavior generated by sequential and periodical contraction of muscles essential for coordinated control of movements of legs and leg joints. Studies of walking in vertebrates and invertebrates have revealed that premotor neural circuitry generates a basic rhythmic pattern that is sculpted by sensory feedback and ultimately controls the amplitude and phase of the motor output to leg muscles. However, the identity and functional roles of the premotor interneurons that directly control leg motoneuron activity are poorly understood. Here we take advantage of the powerful genetic methodology available in Drosophila to investigate the role of premotor inhibition in walking by genetically suppressing inhibitory input to leg motoneurons. For this, we have developed an algorithm for automated analysis of leg motion to characterize the walking parameters of wild-type flies from high-speed video recordings. Further, we use genetic reagents for targeted RNAi knockdown of inhibitory neurotransmitter receptors in leg motoneurons together with quantitative analysis of resulting changes in leg movement parameters in freely walking Drosophila. Our findings indicate that targeted down-regulation of the GABAA receptor Rdl (Resistance to Dieldrin) in leg motoneurons results in a dramatic reduction of walking speed and step length without the loss of general leg coordination during locomotion. Genetically restricting the knockdown to the adult stage and subsets of motoneurons yields qualitatively identical results. Taken together, these findings identify GABAergic premotor inhibition of motoneurons as an important determinant of correctly coordinated leg movements and speed of walking in freely behaving Drosophila. PMID:29440493

GABAergic inhibition of leg motoneurons is required for normal walking behavior in freely moving Drosophila.

PubMed

Gowda, Swetha B M; Paranjpe, Pushkar D; Reddy, O Venkateswara; Thiagarajan, Devasena; Palliyil, Sudhir; Reichert, Heinrich; VijayRaghavan, K

2018-02-27

Walking is a complex rhythmic locomotor behavior generated by sequential and periodical contraction of muscles essential for coordinated control of movements of legs and leg joints. Studies of walking in vertebrates and invertebrates have revealed that premotor neural circuitry generates a basic rhythmic pattern that is sculpted by sensory feedback and ultimately controls the amplitude and phase of the motor output to leg muscles. However, the identity and functional roles of the premotor interneurons that directly control leg motoneuron activity are poorly understood. Here we take advantage of the powerful genetic methodology available in Drosophila to investigate the role of premotor inhibition in walking by genetically suppressing inhibitory input to leg motoneurons. For this, we have developed an algorithm for automated analysis of leg motion to characterize the walking parameters of wild-type flies from high-speed video recordings. Further, we use genetic reagents for targeted RNAi knockdown of inhibitory neurotransmitter receptors in leg motoneurons together with quantitative analysis of resulting changes in leg movement parameters in freely walking Drosophila Our findings indicate that targeted down-regulation of the GABA A receptor Rdl (Resistance to Dieldrin) in leg motoneurons results in a dramatic reduction of walking speed and step length without the loss of general leg coordination during locomotion. Genetically restricting the knockdown to the adult stage and subsets of motoneurons yields qualitatively identical results. Taken together, these findings identify GABAergic premotor inhibition of motoneurons as an important determinant of correctly coordinated leg movements and speed of walking in freely behaving Drosophila . Copyright © 2018 the Author(s). Published by PNAS.

Sports Ultrasound: Applications Beyond the Musculoskeletal System.

PubMed

Finnoff, Jonathan T; Ray, Jeremiah; Corrado, Gianmichael; Kerkhof, Deanna; Hill, John

2016-09-01

Traditionally, ultrasound has been used to evaluate musculoskeletal injuries in athletes; however, ultrasound applications extend well beyond musculoskeletal conditions, many of which are pertinent to athletes. Articles were identified in PubMed using the search terms ultrasound, echocardiogram, preparticipation physical examination, glycogen, focused assessment with sonography of trauma, optic nerve, and vocal cord dysfunction. No date restrictions were placed on the literature search. Clinical review. Level 4. Several potential applications of nonmusculoskeletal ultrasound in sports medicine are presented, including extended Focused Assessment with Sonography for Trauma (eFAST), limited echocardiographic screening during preparticipation physical examinations, assessment of muscle glycogen stores, optic nerve sheath diameter measurements in athletes with increased intracranial pressure, and assessment of vocal cord dysfunction in athletes. Ultrasound can potentially be used to assist athletes with monitoring their muscle glycogen stores and the diagnosis of multiple nonmusculoskeletal conditions within sports medicine. © 2016 The Author(s).

Simvastatin-lnduced nocturnal leg pain disappears with pravastatin substitution.

PubMed

Stojaković, Natasa; Igić, Rajko

2013-01-01

Statins have similar side effects that do not always occur at the same rate among the various statins. We present a case of simvastatin-induced muscle toxicity that disappeared when pravastatin was substituted for the original drug. A 74-year-old male, a nonsmoker, complained of severe nocturnal leg cramps. The patient also complained that similar painful cramping occurred when he walked rapidly or jogged. Because some components of his lipid panel exceeded the'desirable' range, and as he had a history of myocardial infarction, his family physician prescribed simvastatin (40 mg/day). The patient had taken this medication for the past eight years. The painful nocturnal episodes started two years ago and affected either one or the other leg. Four months ago we discontinued his simvastatin and prescribed pravastatin (80 mg/day). At a follow-up visit six weeks later, the patient reported that his leg pains at night and the pain experienced after brisk walking had disappeared. Four months after the substitution of pravastatin for simvastatin, the patient reported that his complete lack of symptoms had continued. These painful muscle cramps were probably caused by an inadequate vascular supply to the calf and foot muscles. Perhaps a combination of advanced age and atherosclerotic changes created a predisposition for the simvastatin-induced leg cramps. Pravastatin differs from simvastatin in several ways.l It is not metabolized by cytochrome P450 (CYP) 3A4 oxidases, and thus is not influenced by CYP 3A4 inhibitors like simvastatin. Also, simvastatin is associated with single-nucleotide polymorphisms located within the SLCO1B1 gene on the chromosome 12 and established myopathy, while pravastatin lacks this association. These differences may contribute to increased tolerance to pravastatin in this particular case.

Fluid shifts and muscle function in humans during acute simulated weightlessness

NASA Technical Reports Server (NTRS)

Hargens, A. R.; Tipton, C. M.; Gollnick, P. D.; Mubarak, S. J.; Tucker, B. J.; Akeson, W. H.

1983-01-01

The acute effects of simulated weightlessness on transcapillary fluid balance, tissue fluid shifts, muscle function, and triceps surface reflex time were studied in eight supine human subjects who were placed in a 5 degrees head-down tilt position for 8 hr. Results show a cephalic fluid shift from the legs as indicated by facial edema, nasal congestion, increased urine flow, decreased creatinine excretion, reduced calf girth, and decreased lower leg volume. The interstitial fluid pressure in the tibialis anterior muscle and subcutaneous tissue of the lower leg was found to fall significantly, while other transcapillary pressures (capillary and interstitial fluid colloid osmotic pressures) were relatively unchanged. The total water content of the soleus muscle was unchanged during the head-down tilt. After head-down tilt, isometric strength and isokinetic strength of the plantar flexors were unchanged, while the triceps surae reflex time associated with plantar flexion movement slowed slightly. These results demonstrate a dehydration effect of head-down tilt on muscle and subcutaneous tissue of the lower leg that may affect muscle function.

Dyssynchronous breathing during arm but not leg exercise in patients with chronic airflow obstruction.

PubMed

Celli, B R; Rassulo, J; Make, B J

1986-06-05

Some patients with chronic airflow obstruction experience dyspnea with mild arm exercise but not with more-intense leg exercise. To investigate why these patients have limited endurance during arm exertion, we studied ventilatory responses to exercise with unsupported arms in 12 patients with chronic airflow obstruction (mean [+/- SD] forced expiratory volume in one second, 0.68 +/- 0.28 liters). Unloaded leg cycling was also studied for comparison. In the five patients who had the most severe airflow obstruction, arm exercise was limited by dyspnea after 3.3 +/- 0.7 minutes, and dyssynchronous thoracoabdominal breathing developed. In the other seven patients, arm exercise was limited by the sensation of muscle fatigue after 6.1 +/- 2.0 minutes (P less than 0.05), and dyssynchronous breathing did not occur. None of the 12 patients had dyssynchronous breathing during unloaded leg cycling. Maximal transdiaphragmatic pressure, a measure of diaphragmatic fatigue, declined similarly after arm and leg exercise in both groups. During unsupported arm work, the accessory muscles of inspiration help position the torso and arms. We hypothesize that the extra demand placed on these muscles during arm exertion leads to early fatigue, an increased load on the diaphragm, and dyssynchronous thoracoabdominal inspirations. This sequence may contribute to dyspnea and limited endurance during upper-extremity exercise.

Force encoding in stick insect legs delineates a reference frame for motor control

PubMed Central

Schmitz, Josef; Chaudhry, Sumaiya; Büschges, Ansgar

2012-01-01

The regulation of forces is integral to motor control. However, it is unclear how information from sense organs that detect forces at individual muscles or joints is incorporated into a frame of reference for motor control. Campaniform sensilla are receptors that monitor forces by cuticular strains. We studied how loads and muscle forces are encoded by trochanteral campaniform sensilla in stick insects. Forces were applied to the middle leg to emulate loading and/or muscle contractions. Selective sensory ablations limited activities recorded in the main leg nerve to specific receptor groups. The trochanteral campaniform sensilla consist of four discrete groups. We found that the dorsal groups (Groups 3 and 4) encoded force increases and decreases in the plane of movement of the coxo-trochanteral joint. Group 3 receptors discharged to increases in dorsal loading and decreases in ventral load. Group 4 showed the reverse directional sensitivities. Vigorous, directional responses also occurred to contractions of the trochanteral depressor muscle and to forces applied at the muscle insertion. All sensory discharges encoded the amplitude and rate of loading or muscle force. Stimulation of the receptors produced reflex effects in the depressor motoneurons that could reverse in sign during active movements. These data, in conjunction with findings of previous studies, support a model in which the trochanteral receptors function as an array that can detect forces in all directions relative to the intrinsic plane of leg movement. The array could provide requisite information about forces and simplify the control and adaptation of posture and walking. PMID:22673329

Use of muscle synergies and wavelet transforms to identify fatigue during squatting.

PubMed

Smale, Kenneth B; Shourijeh, Mohammad S; Benoit, Daniel L

2016-06-01

The objective of this study was to supplement continuous wavelet transforms with muscle synergies in a fatigue analysis to better describe the combination of decreased firing frequency and altered activation profiles during dynamic muscle contractions. Nine healthy young individuals completed the dynamic tasks before and after they squatted with a standard Olympic bar until complete exhaustion. Electromyography (EMG) profiles were analyzed with a novel concatenated non-negative matrix factorization method that decomposed EMG signals into muscle synergies. Muscle synergy analysis provides the activation pattern of the muscles while continuous wavelet transforms output the temporal frequency content of the EMG signals. Synergy analysis revealed subtle changes in two-legged squatting after fatigue while differences in one-legged squatting were more pronounced and included the shift from a general co-activation of muscles in the pre-fatigue state to a knee extensor dominant weighting post-fatigue. Continuous wavelet transforms showed major frequency content decreases in two-legged squatting after fatigue while very few frequency changes occurred in one-legged squatting. It was observed that the combination of methods is an effective way of describing muscle fatigue and that muscle activation patterns play a very important role in maintaining the overall joint kinetics after fatigue. Copyright © 2016 Elsevier Ltd. All rights reserved.

Squeezing the muscle: compression clothing and muscle metabolism during recovery from high intensity exercise.

PubMed

Sperlich, Billy; Born, Dennis-Peter; Kaskinoro, Kimmo; Kalliokoski, Kari K; Laaksonen, Marko S

2013-01-01

The purpose of this experiment was to investigate skeletal muscle blood flow and glucose uptake in m. biceps (BF) and m. quadriceps femoris (QF) 1) during recovery from high intensity cycle exercise, and 2) while wearing a compression short applying ~37 mmHg to the thigh muscles. Blood flow and glucose uptake were measured in the compressed and non-compressed leg of 6 healthy men by using positron emission tomography. At baseline blood flow in QF (P = 0.79) and BF (P = 0.90) did not differ between the compressed and the non-compressed leg. During recovery muscle blood flow was higher compared to baseline in both compressed (P<0.01) and non-compressed QF (P<0.001) but not in compressed (P = 0.41) and non-compressed BF (P = 0.05; effect size = 2.74). During recovery blood flow was lower in compressed QF (P<0.01) but not in BF (P = 0.26) compared to the non-compressed muscles. During baseline and recovery no differences in blood flow were detected between the superficial and deep parts of QF in both, compressed (baseline P = 0.79; recovery P = 0.68) and non-compressed leg (baseline P = 0.64; recovery P = 0.06). During recovery glucose uptake was higher in QF compared to BF in both conditions (P<0.01) with no difference between the compressed and non-compressed thigh. Glucose uptake was higher in the deep compared to the superficial parts of QF (compression leg P = 0.02). These results demonstrate that wearing compression shorts with ~37 mmHg of external pressure reduces blood flow both in the deep and superficial regions of muscle tissue during recovery from high intensity exercise but does not affect glucose uptake in BF and QF.

Muscle-driven finite element simulation of human foot movements.

PubMed

Spyrou, L A; Aravas, N

2012-01-01

This paper describes a finite element scheme for realistic muscle-driven simulation of human foot movements. The scheme is used to simulate human ankle plantar flexion. A three-dimensional anatomically detailed finite element model of human foot and lower leg is developed and the idea of generating natural foot movement based entirely on the contraction of the plantar flexor muscles is used. The bones, ligaments, articular cartilage, muscles, tendons, as well as the rest soft tissues of human foot and lower leg are included in the model. A realistic three-dimensional continuum constitutive model that describes the biomechanical behaviour of muscles and tendons is used. Both the active and passive properties of muscle tissue are accounted for. The materials for bones and ligaments are considered as homogeneous, isotropic and linearly elastic, whereas the articular cartilage and the rest soft tissues (mainly fat) are defined as hyperelastic materials. The model is used to estimate muscle tissue deformations as well as stresses and strains that develop in the lower leg muscles during plantar flexion of the ankle. Stresses and strains that develop in Achilles tendon during such a movement are also investigated.

Expiratory muscle loading increases intercostal muscle blood flow during leg exercise in healthy humans

PubMed Central

Athanasopoulos, Dimitris; Louvaris, Zafeiris; Cherouveim, Evgenia; Andrianopoulos, Vasilis; Roussos, Charis; Zakynthinos, Spyros

2010-01-01

We investigated whether expiratory muscle loading induced by the application of expiratory flow limitation (EFL) during exercise in healthy subjects causes a reduction in quadriceps muscle blood flow in favor of the blood flow to the intercostal muscles. We hypothesized that, during exercise with EFL quadriceps muscle blood flow would be reduced, whereas intercostal muscle blood flow would be increased compared with exercise without EFL. We initially performed an incremental exercise test on eight healthy male subjects with a Starling resistor in the expiratory line limiting expiratory flow to ∼ 1 l/s to determine peak EFL exercise workload. On a different day, two constant-load exercise trials were performed in a balanced ordering sequence, during which subjects exercised with or without EFL at peak EFL exercise workload for 6 min. Intercostal (probe over the 7th intercostal space) and vastus lateralis muscle blood flow index (BFI) was calculated by near-infrared spectroscopy using indocyanine green, whereas cardiac output (CO) was measured by an impedance cardiography technique. At exercise termination, CO and stroke volume were not significantly different during exercise, with or without EFL (CO: 16.5 vs. 15.2 l/min, stroke volume: 104 vs. 107 ml/beat). Quadriceps muscle BFI during exercise with EFL (5.4 nM/s) was significantly (P = 0.043) lower compared with exercise without EFL (7.6 nM/s), whereas intercostal muscle BFI during exercise with EFL (3.5 nM/s) was significantly (P = 0.021) greater compared with that recorded during control exercise (0.4 nM/s). In conclusion, increased respiratory muscle loading during exercise in healthy humans causes an increase in blood flow to the intercostal muscles and a concomitant decrease in quadriceps muscle blood flow. PMID:20507965

Gender differences in muscle inflammation after eccentric exercise.

PubMed

Stupka, N; Lowther, S; Chorneyko, K; Bourgeois, J M; Hogben, C; Tarnopolsky, M A

2000-12-01

Unaccustomed exercise is followed by delayed-onset muscle soreness and morphological changes in skeletal muscle. Animal studies have demonstrated that women have an attenuated response to muscle damage. We studied the effect of eccentric exercise in untrained male (n = 8) and female (n = 8) subjects using a unilateral exercise design [exercise (Ex) and control (Con) legs]. Plasma granulocyte counts [before (Pre) and 48 h after exercise (+48h)] and creatine kinase activity [Pre, 24 h after exercise (+24h), +48h, and 6 days after exercise (+6d)] were determined before (Pre) and after (+24h, +48h, +6d) exercise, with biopsies taken from the vastus lateralis of each leg at +48h for determination of muscle damage and/or inflammation. Plasma granulocyte counts increased for men and decreased for women at +48h (P < 0.05), and creatine kinase activity increased for both genders at +48h and +6d (P < 0.01). There were significantly greater areas of both focal (P < 0.001) and extensive (P < 0.01) damage in the Ex vs. Con leg for both genders, which was assessed by using toluidine blue staining. The number of leukocyte common antigen-positive cells/mm(2) tissue increased with exercise (P < 0.05), and men tended to show more in their Ex vs. Con leg compared with women (P = 0.052). Men had a greater total (Ex and Con legs) number of bcl-2-positive cells/mm(2) tissue vs. women (P < 0.05). Atrophic fibers with homogeneous bcl-2-positive staining were seen only in men (n = 3). We conclude that muscle damage is similar between genders, yet the inflammatory response is attenuated in women vs. men. Finally, exercise may stimulate the expression of proteins involved in apoptosis in skeletal muscle.

Ankle Joint Angle and Lower Leg Musculotendinous Unit Responses to Cryotherapy.

PubMed

Akehi, Kazuma; Long, Blaine C; Warren, Aric J; Goad, Carla L

2016-09-01

Akehi, K, Long, BC, Warren, AJ, and Goad, CL. Ankle joint angle and lower leg musculotendinous unit responses to cryotherapy. J Strength Cond Res 30(9): 2482-2492, 2016-The use of cold application has been debated for its influence on joint range of motion (ROM) and stiffness. The purpose of this study was to determine whether a 30-minute ice bag application to the plantarflexor muscles or ankle influences passive ankle dorsiflexion ROM and lower leg musculotendinous stiffness (MTS). Thirty-five recreationally active college-aged individuals with no history of lower leg injury 6 months before data collection volunteered. On each testing day, we measured maximum passive ankle dorsiflexion ROM (°) and plantarflexor torque (N·m) on an isokinetic dynamometer to calculate the passive plantarflexor MTS (N·m per degree) at 4 joint angles before, during, and after a treatment. Surface electromyography amplitudes (μV), and skin surface and ambient air temperature (°C) were also measured. Subjects received an ice bag to the posterior lower leg, ankle joint, or nothing for 30 minutes in different days. Ice bag application to the lower leg and ankle did not influence passive ROM (F(12,396) = 0.67, p = 0.78). Passive torque increased after ice bag application to the lower leg (F(12,396) = 2.21, p = 0.011). Passive MTS at the initial joint angle increased after ice bag application to the lower leg (F(12,396) = 2.14, p = 0.014) but not at the other joint angles (p > 0.05). Surface electromyography amplitudes for gastrocnemius and soleus muscles increased after ice application to the lower leg (F(2,66) = 5.61, p = 0.006; F(12,396) = 3.60, p < 0.001). Ice bag application to the lower leg and ankle joint does not alter passive dorsiflexion ROM but increases passive ankle plantarflexor torque in addition to passive ankle plantarflexor MTS at the initial joint angle.

Muscle power failure in mobility-limited adults: preserved single muscle fibre function despite reduced whole muscle size, quality and neuromuscular activiation

USDA-ARS?s Scientific Manuscript database

This study investigated the physiological and gender determinants of the age-related loss of muscle power in 31 healthy middle-aged adults (aged 40-55 years), 28 healthy older adults (70-85 years) and 34 mobility-limited older adults (70-85 years). We hypothesized that leg extensor muscle power woul...

Running in the real world: adjusting leg stiffness for different surfaces

NASA Technical Reports Server (NTRS)

Ferris, D. P.; Louie, M.; Farley, C. T.

1998-01-01

A running animal coordinates the actions of many muscles, tendons, and ligaments in its leg so that the overall leg behaves like a single mechanical spring during ground contact. Experimental observations have revealed that an animal's leg stiffness is independent of both speed and gravity level, suggesting that it is dictated by inherent musculoskeletal properties. However, if leg stiffness was invariant, the biomechanics of running (e.g. peak ground reaction force and ground contact time) would change when an animal encountered different surfaces in the natural world. We found that human runners adjust their leg stiffness to accommodate changes in surface stiffness, allowing them to maintain similar running mechanics on different surfaces. These results provide important insight into mechanics and control of animal locomotion and suggest that incorporating an adjustable leg stiffness in the design of hopping and running robots is important if they are to match the agility and speed of animals on varied terrain.

Impaired Skeletal Muscle Vasodilation during Exercise in Heart Failure with Preserved Ejection Fraction

PubMed Central

Lee, Joshua F.; Barrett-O’Keefe, Zachary; Nelson, Ashley D.; Garten, Ryan S.; Ryan, John J.; Nativi-Nicolau, Jose N.; Richardson, Russell S.; Wray, D. Walter

2016-01-01

Background Exercise intolerance is a hallmark symptom of heart failure patients with preserved ejection fraction (HFpEF), which may be related to an impaired ability to appropriately increase blood flow to the exercising muscle. Methods We evaluated leg blood flow (LBF, ultrasound Doppler), heart rate (HR), stroke volume (SV), cardiac output (CO), and mean arterial blood pressure (MAP, photoplethysmography) during dynamic, single leg knee-extensor (KE) exercise in HFpEF patients (n = 21; 68 ± 2 yrs) and healthy controls (n = 20; 71 ± 2 yrs). Results HFpEF patients exhibited a marked attrition during KE exercise, with only 60% able to complete the exercise protocol. In participants who completed all exercise intensities (0-5-10-15W; HFpEF, n = 13; Controls, n = 16), LBF was not different at 0W and 5W, but was 15-25% lower in HFpEF compared to controls at 10W and 15W (P < 0.001). Likewise, leg vascular conductance (LVC), an index of vasodilation, was not different at 0W and 5W, but was 15-20% lower in HFpEF compared to controls at 10W and 15W (P < 0.05). In contrast to these peripheral deficits, exercise-induced changes in central variables (HR, SV, CO), as well as MAP, were similar between groups. Conclusions These data reveal a marked reduction in LBF and LVC in HFpEF patients during exercise that cannot be attributed to a disease-related alteration in central hemodynamics, suggesting that impaired vasodilation in the exercising skeletal muscle vasculature may play a key role in the exercise intolerance associated with this patient population. PMID:26970959

Reliability of ultrasound thickness measurement of the abdominal muscles during clinical isometric endurance tests.

PubMed

ShahAli, Shabnam; Arab, Amir Massoud; Talebian, Saeed; Ebrahimi, Esmaeil; Bahmani, Andia; Karimi, Noureddin; Nabavi, Hoda

2015-07-01

The study was designed to evaluate the intra-examiner reliability of ultrasound (US) thickness measurement of abdominal muscles activity when supine lying and during two isometric endurance tests in subjects with and without Low back pain (LBP). A total of 19 women (9 with LBP, 10 without LBP) participated in the study. Within-day reliability of the US thickness measurements at supine lying and the two isometric endurance tests were assessed in all subjects. The intra-class correlation coefficient (ICC) was used to assess the relative reliability of thickness measurement. The standard error of measurement (SEM), minimal detectable change (MDC) and the coefficient of variation (CV) were used to evaluate the absolute reliability. Results indicated high ICC scores (0.73-0.99) and also small SEM and MDC scores for within-day reliability assessment. The Bland-Altman plots of agreement in US measurement of the abdominal muscles during the two isometric endurance tests demonstrated that 95% of the observations fall between the limits of agreement for test and retest measurements. Together the results indicate high intra-tester reliability for the US measurement of the thickness of abdominal muscles in all the positions tested. According to the study's findings, US imaging can be used as a reliable method for assessment of abdominal muscles activity in supine lying and the two isometric endurance tests employed, in participants with and without LBP. Copyright © 2014 Elsevier Ltd. All rights reserved.

Real-time control of focused ultrasound heating based on rapid MR thermometry.

PubMed

Vimeux, F C; De Zwart, J A; Palussiére, J; Fawaz, R; Delalande, C; Canioni, P; Grenier, N; Moonen, C T

1999-03-01

Real-time control of the heating procedure is essential for hyperthermia applications of focused ultrasound (FUS). The objective of this study is to demonstrate the feasibility of MRI-controlled FUS. An automatic control system was developed using a dedicated interface between the MR system control computer and the FUS wave generator. Two algorithms were used to regulate FUS power to maintain the focal point temperature at a desired level. Automatic control of FUS power level was demonstrated ex vivo at three target temperature levels (increase of 5 degrees C, 10 degrees C, and 30 degrees C above room temperature) during 30-minute hyperthermic periods. Preliminary in vivo results on rat leg muscle confirm that necrosis estimate, calculated on-line during FUS sonication, allows prediction of tissue damage. CONCLUSIONS. The feasibility of fully automatic FUS control based on MRI thermometry has been demonstrated.

Ultrasound elastography-based assessment of the elasticity of the supraspinatus muscle in impingement syndrome: does elastography has any diagnostic value?

PubMed

Demirel, Adnan; Baykara, Murat; Koca, Tuba Tülay; Berk, Ejder

2018-06-01

Ultrasound elastography (UE) is a new ultrasound-based imaging technique that provides information about elasticity and stiffness of tissues. This cross-sectional study aimed to identify the diagnostic importance of UE in supraspinatus impingement syndrome. Forty-one subjects, aged 38-70 years, were included in the study. UE was used to determine the elasticity of the supraspinatus muscle. The strain ratio was calculated as the evaluation criteria to measure the elasticity of the muscle. High strain ratio indicated low elasticity. The measurements were made by the blinded radiologist while the patients sat with their shoulder in a neutral position. The diagnostic value of the strain ratio was evaluated using the receiver operating characteristic (ROC) analysis. The mean strain value of the supraspinatus muscle on the intact and pathological shoulders determined by UE was 0.74 ± 0.33 and 0.31 ± 0.24, respectively. A low strain ratio value in the supraspinatus muscle on the side with impingement syndrome was measured. When the test variable was evaluated as "strain ratio" according to ROC curve analysis, it was found to be above the reference line [0.849 (> 0.5)] (P = 0.00). When the cutoff value was selected as 0.495, the sensitivity and specificity were found to be 75.6 and 78% (the strain ratio value > 0.495), respectively. Measurement of strain ratio with UE can be used as a noninvasive, inexpensive, and practical diagnostic test for the shoulder impingement disease.

Pulmonary and leg VO2 during submaximal exercise: implications for muscular efficiency

NASA Technical Reports Server (NTRS)

Poole, D. C.; Gaesser, G. A.; Hogan, M. C.; Knight, D. R.; Wagner, P. D.

1992-01-01

Insights into muscle energetics during exercise (e.g., muscular efficiency) are often inferred from measurements of pulmonary gas exchange. This procedure presupposes that changes of pulmonary O2 (VO2) associated with increases of external work reflect accurately the increased muscle VO2. The present investigation addressed this issue directly by making simultaneous determinations of pulmonary and leg VO2 over a range of work rates calculated to elicit 20-90% of maximum VO2 on the basis of prior incremental (25 or 30 W/min) cycle ergometry. VO2 for both legs was calculated as the product of twice one-leg blood flow (constant-infusion thermodilution) and arteriovenous O2 content difference across the leg. Measurements were made 3-5 min after each work rate imposition to avoid incorporation of the VO2 slow component above the lactate threshold. For all 17 subjects, the slope of pulmonary VO2 (9.9 +/- 0.2 ml O2.W-1.min-1) was not different (P greater than 0.05) from that for leg VO2 (9.2 +/- 0.6 ml O2.W-1.min-1). Estimation of "delta" efficiency (i.e., delta work accomplished divided by delta energy expended, calculated from slope of VO2 vs. work rate and a caloric equivalent for O2 of 4.985 cal/ml) using pulmonary VO2 measurements (29.1 +/- 0.6%) was likewise not significantly different (P greater than 0.05) from that made using leg VO2 measurements (33.7 +/- 2.4%). These data suggest that the net VO2 cost of metabolic "support" processes outside the exercising legs changes little over a relatively broad range of exercise intensities. Thus, under the conditions of this investigation, changes of VO2 measured from expired gas reflected closely those occurring within the exercising legs.

Radiating leg pain and positive straight leg raising in spondylolysis in children.

PubMed

Halperin, N; Copeliovitch, L; Schachner, E

1983-09-01

Three children presented with low back pain radiating to the leg and with spasm of the hamstring and paravertebral muscles. Since the pain could not be ascribed to trauma, it was necessary to exclude the presence of infection or tumors. All the signs--localization of the pain, tenderness on one side of the back, X-ray film findings of unilateral or bilateral spondylolysis, and localized positive bone scan--pointed to spondylolysis as the cause of pain. All three children exhibited symptoms resembling those found in the facet syndrome described by Mooney and Robertson.

Effects of Acute Fatigue of the Hip Flexor Muscles on Hamstring Muscle Extensibility.

PubMed

Muyor, José M; Arrabal-Campos, Francisco M

2016-12-01

The purpose of the present study was to evaluate the influence of acute fatigue of the hip flexor muscles on scores attained in tests frequently used in literature to measure hamstring muscle extensibility, namely the passive straight leg raise (PSLR), active straight leg raise (ASLR), passive knee extension (PKE), active knee extension (AKE), sit-and-reach (SR) and toe-touch (TT) tests. A total of seventy-five healthy and recreationally active adults voluntarily participated in this study. To reach fatigue, the participants actively lifted their legs alternately as many times as possible. In the passive tests, the results were 7.10 ± 5.21° and 5.68 ± 4.54° higher (p < 0.01) for PSLR and PKE tests, respectively, after acute fatigue. However, in the ASLR test, the results were lower post-fatigue than pre-fatigue (mean difference = -5.30° ± 9.51°; p < 0.01). The AKE, SR and TT tests did not show significant differences between pre- and post-fatigue (p > 0.05). Moderate (r = 0.40) to high (r = 0.97) correlation coefficients were found, which were statistically significant among all the measured flexibility tests both pre- and post-fatigue. In conclusion, the active implication of the hip flexor muscles until reaching fatigue had acute influences on the results of the PSLR, PKE and ASLR tests, but not on the results of the AKE, SR and TT tests. It is recommended to use the AKE test to assess hamstring muscle extensibility in situations where athletes show fatigue in their hip flexor muscles.

Synchronous monitoring of muscle dynamics and muscle force for maximum isometric tetanus

NASA Astrophysics Data System (ADS)

Zakir Hossain, M.; Grill, Wolfgang

2010-03-01

Skeletal muscle is a classic example of a biological soft matter . At both macro and microscopic levels, skeletal muscle is exquisitely oriented for force generation and movement. In addition to the dynamics of contracting and relaxing muscle which can be monitored with ultrasound, variations in the muscle force are also expected to be monitored. To observe such force and sideways expansion variations synchronously for the skeletal muscle a novel detection scheme has been developed. As already introduced for the detection of sideways expansion variations of the muscle, ultrasonic transducers are mounted sideways on opposing positions of the monitored muscle. To detect variations of the muscle force, angle of pull of the monitored muscle has been restricted by the mechanical pull of the sonic force sensor. Under this condition, any variation in the time-of-flight (TOF) of the transmitted ultrasonic signals can be introduced by the variation of the path length between the transducers. The observed variations of the TOF are compared to the signals obtained by ultrasound monitoring for the muscle dynamics. The general behavior of the muscle dynamics and muscle force shows almost an identical concept. Since muscle force also relates the psychological boosting-up effects, the influence of boosting-up on muscle force and muscle dynamics can also be quantified form this study. Length-tension or force-length and force-velocity relationship can also be derived quantitatively with such monitoring.

Muscle Contributions to Frontal Plane Angular Momentum during Walking

PubMed Central

Neptune, Richard R.; McGowan, Craig P.

2016-01-01

The regulation of whole-body angular momentum is important for maintaining dynamic balance during human walking, which is particularly challenging in the frontal plane. Whole-body angular momentum is actively regulated by individual muscle forces. Thus, understanding which muscles contribute to frontal plane angular momentum will further our understanding of mediolateral balance control and has the potential to help diagnose and treat balance disorders. The purpose of this study was to identify how individual muscles and gravity contribute to whole-body angular momentum in the frontal plane using a muscle-actuated forward dynamics simulation analysis. A three-dimensional simulation was developed that emulated the average walking mechanics of a group of young healthy adults (n=10). The results showed that a finite set of muscles are the primary contributors to frontal plane balance and that these contributions vary throughout the gait cycle. In early stance, the vasti, adductor magnus and gravity acted to rotate the body towards the contralateral leg while the gluteus medius acted to rotate the body towards the ipsilateral leg. In late stance, the gluteus medius continued to rotate the body towards the ipsilateral leg while the soleus and gastrocnemius acted to rotate the body towards the contralateral leg. These results highlight those muscles that are critical to maintaining dynamic balance in the frontal plane during walking and may provide targets for locomotor therapies aimed at treating balance disorders. PMID:27522538

Ultrasound Assessment of Abdominal Muscle Thickness in Women With and Without Low Back Pain During Pregnancy.

PubMed

Weis, Carol Ann; Nash, Jennifer; Triano, John J; Barrett, Jon

2017-05-01

The aim of this preliminary study was to determine the differences in abdominal musculature thickness, within 1 month of delivery, in women who experienced back pain during pregnancy compared with those who did not. B-mode ultrasound imaging was used to measure abdominal muscle thickness on 76 postpartum participants who participated in a larger study; 47 women experienced back pain during pregnancy, and 29 did not. Participant data were stratified by group, and primary comparisons were based on these grouping across the abdominal muscles, including rectus abdominis (upper and lower fibers), external oblique, internal oblique, and transversus abdominis. Means and standard deviations were also used to set parameters for future studies. In the present study, there was no difference in any abdominal muscle thickness between groups. Women with low back pain were significantly shorter (165.19 ± 6.64 cm) than women who did not have from back pain during pregnancy (169.38 ± 7.58 cm). All other demographics, such as age, weight, and date tested postpartum, were not significantly different between groups. The results of this study showed no variation in abdominal muscle thickness in women who had back pain during pregnancy and those who did not. Copyright © 2017. Published by Elsevier Inc.

Muscle fiber type, Achilles tendon length, potentiation, and running economy.

PubMed

Hunter, Gary R; McCarthy, John P; Carter, Stephen J; Bamman, Marcas M; Gaddy, Emily S; Fisher, Gordon; Katsoulis, Kostantina; Plaisance, Eric P; Newcomer, Bradley R

2015-05-01

The purpose of this investigation was to develop a potential model for how muscle fiber type, Achilles tendon length, stretch-shortening cycle potentiation (SSCP), and leg strength interact with running economy. Twenty trained male distance runners 24-40 years of age served as subjects. Running economy (net oxygen uptake) was measured while running on a treadmill. Leg press SSCP(force) and SSCP(velocity) were determined by measuring the difference in velocity between a static leg press throw and a countermovement leg press throw. Vertical jump SSCP was determined by measuring the difference in jump height between a static jump and a drop jump from a 20.3-cm bench. Tendon length was measured by magnetic resonance imaging, and muscle fiber type was made from a vastus lateralis muscle biopsy. Type IIx muscle fiber percent (r = 0.70, p < 0.001) and leg strength (r = 0.95, p < 0.001) were positively and independently related to late eccentric force development. Achilles tendon length (r = 0.42, p ≤ 0.05) and late eccentric force during stretch-shortening cycle (r = 0.76, p < 0.001) were independently related to SSCP(force). SSCP(force) was related to SSCP(velocity), which in turn was related to running economy (r = 0.61, p < 0.01). These results suggest that longer Achilles tendon length, type II fiber, and muscular leg strength may enhance the potential for SSCP, running economy, and physiological effort while running.

Immediate Effects of Kinesiology Taping of Quadriceps on Motor Performance after Muscle Fatigued Induction.

PubMed

Ahn, Ick Keun; Kim, You Lim; Bae, Young-Hyeon; Lee, Suk Min

2015-01-01

Objectives. The purpose of this cross-sectional single-blind study was to investigate the immediate effects of Kinesiology taping of quadriceps on motor performance after muscle fatigued induction. Design. Randomized controlled cross-sectional design. Subjects. Forty-five subjects participated in this study. Participants were divided into three groups: Kinesiology taping group, placebo taping group, and nontaping group. Methods. Subjects performed short-term exercise for muscle fatigued induction, followed by the application of each intervention. Peak torque test, one-leg single hop test, active joint position sense test, and one-leg static balance test were carried out before and after the intervention. Results. Peak torque and single-leg hopping distance were significantly increased when Kinesiology taping was applied (p < 0.05). But there were no significant effects on active joint position sense and single-leg static balance. Conclusions. We proved that Kinesiology taping is effective in restoring muscle power reduced after muscle fatigued induction. Therefore, we suggest that Kinesiology taping is beneficial for fatigued muscles.

Evaluation of human muscle hardness after dynamic exercise with ultrasound real-time tissue elastography: a feasibility study.

PubMed

Yanagisawa, O; Niitsu, M; Kurihara, T; Fukubayashi, T

2011-09-01

To assess the feasibility of ultrasound real-time tissue elastography (RTE) for measuring exercise-induced changes in muscle hardness and to compare the findings of RTE with those of a tissue hardness meter for semi-quantitative assessment of the hardness of exercised muscles. Nine male participants performed an arm-curl exercise. RTE measurements were performed by manually applying repetitive compression with the transducer on the scan position before exercise, immediately after exercise, and at 30 min after exercise; strain ratios between muscle and a reference material (hydrogel) were calculated (muscle strain/material strain). A tissue hardness meter was also used to evaluate muscle hardness. The intraclass correlation coefficients (ICCs) for the three repeated measurements at each measurement time were calculated to evaluate the intra-observer reproducibility of each technique. Immediately after exercise, the strain ratio and the value obtained using the tissue hardness meter significantly decreased (from 1.65 to 1.35) and increased (from 51.8 to 54.3), respectively. Both parameters returned to their pre-exercise value 30 min after exercise. The ICCs of the RTE (and the ICCs of the muscle hardness meter) were 0.971 (0.816) before exercise, 0.939 (0.776) immediately after exercise, and 0.959 (0.882) at 30 min after exercise. Similar to the muscle hardness meter, RTE revealed the exercise-induced changes of muscle hardness semi-quantitatively. The intra-observer reproducibility of RTE was very high at each measurement time. These findings suggest that RTE is a clinically useful technique for assessing hardness of specific exercised muscles. Copyright © 2011 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Ultrasound evaluation of intrinsic plantar muscles and fascia in hallux valgus: A case-control study.

PubMed

Lobo, César Calvo; Marín, Alejandro Garrido; Sanz, David Rodríguez; López, Daniel López; López, Patricia Palomo; Morales, Carlos Romero; Corbalán, Irene Sanz

2016-11-01

A cross-sectional area (CSA) and thickness reduction of the abductor hallucis (AbH) is shown in subjects with hallux valgus (HV). To date, other soft-tissue structures have not been researched in relation with HV. The aim of this study was to compare the CSA and thickness of the intrinsic plantar muscles and fascia (PF) between feet with and without HV. Therefore, a cross-sectional and case-control study was performed using B-mode with an iU22 Philips ultrasound system and a 5 to 17-MHz transducer. The CSA and thickness were measured for the AbH, flexor digitorum brevis (FDB) and flexor hallucis brevis (FHB), and also the thickness for the anterior, middle, and posterior PF portions. A convenience sample of 40 feet, 20 with HV and 20 without HV, was recruited from a clinical and research center. A multivariate regression analysis using linear regression was performed to evaluate the ultrasound imaging measurements (α = 0.05). Consequently, statistically significant differences were observed between the groups (P < 0.05) for the AbH and FHB thickness, and CSA reduction, and also the plantar fascia thickness increase in favor of the HV group. On the contrary, the FDB thickness and CSA did not show statistically significant differences (P ≥ 0.05). In conclusion, the CSA and thickness of the AbH and FHB intrinsic plantar muscles are reduced, whereas the thickness of the anterior, middle, and posterior PF portions are increased, in subjects with HV compared with those without HV.

Onset Time of Nerve Block: A Comparison of Two Injection Locations in Patients Having Lower Leg/ Foot Surgery

ClinicalTrials.gov

2014-03-20

Strain of Muscle and/or Tendon of Lower Leg; Fracture of Lower Leg; Crushing Injury of Lower Leg; Fracture Malunion - Ankle and/or Foot; Disorder of Joint of Ankle and/or Foot; Complete Tear, Ankle and/or Foot Ligament; Pathological Fracture - Ankle and/or Foot; Loose Body in Joint of Ankle and/or Foot

Sex differences in anticipatory postural adjustments during rapid single leg lift.

PubMed

Bussey, Melanie D; Castro, Marcelo Peduzzi de; Aldabe, Daniela; Shemmell, Jonathan

2018-02-01

The aim of this study was to assess the influence of sex on the kinetic, kinematic and neuromuscular correlates of anticipatory postural adjustments (APAs) during a single leg lift task performed by healthy participants. Fifty healthy age and body mass index matched participants (25 women and 25 men) performed 20 single leg lift task (hip flexion to 90 ° as quickly as possible) with their dominant and their non-dominant lower limbs. A force plate was used to determine the medial-lateral displacement of the center of pressure (COP ML ), and the initiation of weight shift (T 0 ); kinematics was used to determine leg lift (T 1 ); and electromyography was used to determine onset times from eight muscles: bilateral external oblique, internal oblique and lumbar multifidus, and unilateral (stance limb) gluteus maximus and biceps femoris. Movement control limb dominance was included in the analysis. Statistically significant interactions between sex and limb dominance (p < .001) were observed for T 1 , COP ML, and muscle onsets. Also, statistically significant main effect of sex on T 0 was observed. Women showed increased APA time (T 1 ) and magnitude (COP ML ) in their dominant limbs compared to men. Such differences between sexes did not occur in the non-dominant limb. Women recruited proximal muscles later than their man counterparts. Overall, women appear to have a stronger effect of limb dominance on their anticipatory postural control strategy which requires further investigation. The findings of the current study indicate that women and men differ in their anticipatory postural control strategy for rapid single leg lift. Copyright © 2017 Elsevier B.V. All rights reserved.

Utilization of stored elastic energy in leg extensor muscles by men and women.

PubMed

Komi, P V; Bosco, C

1978-01-01

An alternating cycle of eccentric-concentric contractions in locomotion represents a sequence when storage and utilization of elastic energy takes place. It is possible that this storage capacity and its utilization depends on the imposed stretch loads in activated muscles, and that sex differences may be present in these phenomena. To investigate these assumed differences, subjects from both sexes and of good physical condition performed vertical jumps on the force-platform from the following experimental conditions: squatting jump (SJ) from a static starting position; counter-movement jump (CMJ) from a free standing position and with a preparatory counter-movement; drop jumps (DJ) from the various heights (20 to 100 cm) on to the platform followed immediately by a vertical jump. In all subjects the SJ, in which condition no appreciable storage of elastic energy takes place, produced the lowest height of rise of the whole body center of gravity (C.G.). The stretch load (drop height) influenced the performance so that height of rise of C. of G. increased when the drop height increased from 26 up to 62 cm (males) and from 20 to 50 cm (females). In all jumping conditions the men jumped higher than the women. However, examination of the utilization of elastic energy indicated that in CMJ the female subjects were able to utilize most (congruent to 90%) of the energy produced in the prestretching phase. Similarly, in DJ the overall change in positive energy over SJ condition was higher in women as compared to men. Thus the results suggest that although the leg extensor muscles of the men subjects could sustain much higher stretch loads, the females may be able to utilize a greater portion of the stored elastic energy in jumping activities.

The Influence of Ambulatory Aid on Lower-Extremity Muscle Activation During Gait.

PubMed

Sanders, Michael; Bowden, Anton E; Baker, Spencer; Jensen, Ryan; Nichols, McKenzie; Seeley, Matthew K

2018-05-10

Foot and ankle injuries are common and often require a nonweight-bearing period of immobilization for the involved leg. This nonweight-bearing period usually results in muscle atrophy for the involved leg. There is a dearth of objective data describing muscle activation for different ambulatory aids that are used during the aforementioned nonweight-bearing period. To compare activation amplitudes for 4 leg muscles during (1) able-bodied gait and (2) ambulation involving 3 different ambulatory aids that can be used during the acute phase of foot and ankle injury care. Within-subject, repeated measures. University biomechanics laboratory. Sixteen able-bodied individuals (7 females and 9 males). Each participant performed able-bodied gait and ambulation using 3 different ambulatory aids (traditional axillary crutches, knee scooter, and a novel lower-leg prosthesis). Muscle activation amplitude quantified via mean surface electromyography amplitude throughout the stance phase of ambulation. Numerous statistical differences (P < .05) existed for muscle activation amplitude between the 4 observed muscles, 3 ambulatory aids, and able-bodied gait. For the involved leg, comparing the 3 ambulatory aids: (1) knee scooter ambulation resulted in the greatest vastus lateralis activation, (2) ambulation using the novel prosthesis and traditional crutches resulted in greater biceps femoris activation than knee scooter ambulation, and (3) ambulation using the novel prosthesis resulted in the greatest gastrocnemius activation (P < .05). Generally speaking, muscle activation amplitudes were most similar to able-bodied gait when subjects were ambulating using the knee scooter or novel prosthesis. Type of ambulatory aid influences muscle activation amplitude. Traditional axillary crutches appear to be less likely to mitigate muscle atrophy during the nonweighting, immobilization period that often follows foot or ankle injuries. Researchers and clinicians should consider

Visualization of the diaphragm muscle with ultrasound improves diagnostic accuracy of phrenic nerve conduction studies.

PubMed

Johnson, Nicholas E; Utz, Michael; Patrick, Erica; Rheinwald, Nicole; Downs, Marlene; Dilek, Nuran; Dogra, Vikram; Logigian, Eric L

2014-05-01

Evaluation of phrenic neuropathy (PN) with phrenic nerve conduction studies (PNCS) is associated with false negatives. Visualization of diaphragmatic muscle twitch with diaphragm ultrasound (DUS) when performing PNCS may help to solve this problem. We performed bilateral, simultaneous DUS-PNCS in 10 healthy adults and 12 patients with PN. The amplitude of the diaphragm compound muscle action potential (CMAP) (on PNCS) and twitch (on DUS) was calculated. Control subjects had <38% side-to-side asymmetry in twitch amplitude (on DUS) and 53% asymmetry in phrenic CMAP (on PCNS). In the 12 patients with PN, 12 phrenic neuropathies were detected. Three of these patients had either significant side-to-side asymmetry or absolute reduction in diaphragm movement that was not detected with PNCS. There were no cases in which the PNCS showed an abnormality but the DUS did not. The addition of DUS to PNCS enhances diagnostic accuracy in PN. Copyright © 2013 Wiley Periodicals, Inc.

Effects of training in minimalist shoes on the intrinsic and extrinsic foot muscle volume.

PubMed

Chen, Tony Lin-Wei; Sze, Louis K Y; Davis, Irene S; Cheung, Roy T H

2016-07-01

Minimalist shoes have gained popularity recently because it is speculated to strengthen the foot muscles and foot arches, which may help to resist injuries. However, previous studies provided limited evidence supporting the link between changes in muscle size and footwear transition. Therefore, this study sought to examine the effects of minimalist shoes on the intrinsic and extrinsic foot muscle volume in habitual shod runners. The relationship between participants' compliance with the minimalist shoes and changes in muscle õvolume was also evaluated. Twenty habitual shod runners underwent a 6-month self-monitoring training program designed for minimalist shoe transition. Another 18 characteristics-matched shod runners were also introduced with the same program but they maintained running practice with standard shoes. Runners were monitored using an online surveillance platform during the program. We measured overall intrinsic and extrinsic foot muscle volume before and after the program using MRI scans. Runners in the experimental group exhibited significantly larger leg (P=0.01, Cohen's d=0.62) and foot (P<0.01, Cohen's d=0.54) muscle after transition. Foot muscle growth was mainly contributed by the forefoot (P<0.01, Cohen's d=0.64) but not the rearfoot muscle (P=0.10, Cohen's d=0.30). Leg and foot muscle volume of runners in the control group remained similar after the program (P=0.33-0.95). A significant positive correlation was found between participants' compliance with the minimalist shoes and changes in leg muscle volume (r=0.51; P=0.02). Habitual shod runners who transitioned to minimalist shoes demonstrated significant increase in leg and foot muscle volume. Additionally, the increase in leg muscle volume was significantly correlated associated with the compliance of minimalist shoe use. Copyright © 2016 Elsevier Ltd. All rights reserved.

Changes in muscle strength in patients with statin myalgia.

PubMed

Panza, Gregory A; Taylor, Beth A; Roman, William; Thompson, Paul D

2014-10-15

Statins can produce myalgia or muscle pain, which may affect medication adherence. We measured the effects of statins on muscle strength in patients with previous statin myalgia. Leg isokinetic extension average power at 60° per second (-8.8 ± 10.5N-M, p = 0.02) and average peak torque at 60° per second (-14.0 ± 19.7N-M, p = 0.04) decreased slightly with statin use, but 8 of 10 other variables for leg strength did not change (all p >0.13). Handgrip, muscle pain, respiratory exchange ratio, and daily activity also did not change (all p >0.09). In conclusion, statin myalgia is not associated with reduced muscle strength or muscle performance. Published by Elsevier Inc.

Sympathetic adaptations to one-legged training

NASA Technical Reports Server (NTRS)

Ray, C. A.

1999-01-01

The purpose of the present study was to determine the effect of leg exercise training on sympathetic nerve responses at rest and during dynamic exercise. Six men were trained by using high-intensity interval and prolonged continuous one-legged cycling 4 day/wk, 40 min/day, for 6 wk. Heart rate, mean arterial pressure (MAP), and muscle sympathetic nerve activity (MSNA; peroneal nerve) were measured during 3 min of upright dynamic one-legged knee extensions at 40 W before and after training. After training, peak oxygen uptake in the trained leg increased 19 +/- 2% (P < 0.01). At rest, heart rate decreased from 77 +/- 3 to 71 +/- 6 beats/min (P < 0.01) with no significant changes in MAP (91 +/- 7 to 91 +/- 11 mmHg) and MSNA (29 +/- 3 to 28 +/- 1 bursts/min). During exercise, both heart rate and MAP were lower after training (108 +/- 5 to 96 +/- 5 beats/min and 132 +/- 8 to 119 +/- 4 mmHg, respectively, during the third minute of exercise; P < 0.01). MSNA decreased similarly from rest during the first 2 min of exercise both before and after training. However, MSNA was significantly less during the third minute of exercise after training (32 +/- 2 to 22 +/- 3 bursts/min; P < 0.01). This training effect on MSNA remained when MSNA was expressed as bursts per 100 heartbeats. Responses to exercise in five untrained control subjects were not different at 0 and 6 wk. These results demonstrate that exercise training prolongs the decrease in MSNA during upright leg exercise and indicates that attenuation of MSNA to exercise reported with forearm training also occurs with leg training.

Focused ultrasound and microbubbles for enhanced extravasation.

PubMed

Böhmer, M R; Chlon, C H T; Raju, B I; Chin, C T; Shevchenko, T; Klibanov, A L

2010-11-20

The permeability of blood vessels for albumin can be altered by using ultrasound and polymer or lipid-shelled microbubbles. The region in which the microbubbles were destroyed with focused ultrasound was quantified in gel phantoms as a function of pressure, number of cycles and type of microbubble. At 2MPa the destruction took place in a fairly wide area for a lipid-shelled agent, while for polymer-shelled agents at this setting, distinct destruction spots with a radius of only 1mm were obtained. When microbubbles with a thicker shell were used, the pressure above which the bubbles were destroyed shifts to higher values. In vivo both lipid and polymer microbubbles increased the extravasation of the albumin binding dye Evans Blue, especially in muscle leading to about 6-8% of the injected dose to extravasate per gram muscle tissue 30 min after start of the treatment, while no Evans Blue could be detected in muscle in the absence of microbubbles. Variation in the time between ultrasound treatment and Evans Blue injection, demonstrated that the time window for promoting extravasation is at least an hour at the settings used. In MC38 tumors, extravasation already occurred without ultrasound and only a trend towards enhancement with about a factor of 2 could be established with a maximum percentage injected dose per gram of 3%. Ultrasound mediated microbubble destruction especially enhances the extravasation in the highly vascularized outer part of the MC38 tumor and adjacent muscle and would, therefore, be most useful for release of, for instance, anti-angiogenic drugs. Copyright © 2010 Elsevier B.V. All rights reserved.

Time kinetics of acute changes in muscle architecture in response to resistance exercise.

PubMed

Csapo, Robert; Alegre, Luis M; Baron, Ramon

2011-05-01

The study aimed to assess acute changes in muscle architecture and its recovery after exhaustive exercise. We hypothesised that repetitive leg press exercise would decrease vastus lateralis fascicle length, while increasing both muscle thickness and pennation angles. By investigating the time kinetics of recovery of these parameters, we wished to gain insight into the mechanisms responsible for muscle architectural changes during exercise. Muscle architecture was assessed in 41 male volunteers (25.2±3.7 yrs; 1.78±0.06 m; 76.4±11.7 kg) before and directly after, as well as 5, 10, 15, and 30 min after induction of fatigue by leg press exercise. Vastus lateralis muscle thickness, pennation angles and fascicle lengths were measured at rest by ultrasonography. Muscular fatigue was induced by an exhaustive series of maximum power, single leg press repetitions. Following leg press exercise vastus lateralis muscle thickness and pennation angles were increased by approximately 7 and 10%, whereas fascicle lengths decreased by 2%. Different recovery times (muscle thickness: 30 min; pennation angles: 15 min; fascicle lengths: 5 min) were observed. The differential time courses of recovery suggest that changes in muscle thickness, pennation angles, and fascicle lengths are driven by different exercise-related stimuli. Increased muscle perfusion and tendon creep are likely candidates accounting for short-term changes in muscle architecture. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Ultrasound estimates of muscle quality in older adults: reliability and comparison of Photoshop and ImageJ for the grayscale analysis of muscle echogenicity

PubMed Central

Seamon, Bryant A.; Teixeira, Carla; Ismail, Catheeja

2016-01-01

Background. Quantitative diagnostic ultrasound imaging has been proposed as a method of estimating muscle quality using measures of echogenicity. The Rectangular Marquee Tool (RMT) and the Free Hand Tool (FHT) are two types of editing features used in Photoshop and ImageJ for determining a region of interest (ROI) within an ultrasound image. The primary objective of this study is to determine the intrarater and interrater reliability of Photoshop and ImageJ for the estimate of muscle tissue echogenicity in older adults via grayscale histogram analysis. The secondary objective is to compare the mean grayscale values obtained using both the RMT and FHT methods across both image analysis platforms. Methods. This cross-sectional observational study features 18 community-dwelling men (age = 61.5 ± 2.32 years). Longitudinal views of the rectus femoris were captured using B-mode ultrasound. The ROI for each scan was selected by 2 examiners using the RMT and FHT methods from each software program. Their reliability is assessed using intraclass correlation coefficients (ICCs) and the standard error of the measurement (SEM). Measurement agreement for these values is depicted using Bland-Altman plots. A paired t-test is used to determine mean differences in echogenicity expressed as grayscale values using the RMT and FHT methods to select the post-image acquisition ROI. The degree of association among ROI selection methods and image analysis platforms is analyzed using the coefficient of determination (R2). Results. The raters demonstrated excellent intrarater and interrater reliability using the RMT and FHT methods across both platforms (lower bound 95% CI ICC = .97–.99, p < .001). Mean differences between the echogenicity estimates obtained with the RMT and FHT methods was .87 grayscale levels (95% CI [.54–1.21], p < .0001) using data obtained with both programs. The SEM for Photoshop was .97 and 1.05 grayscale levels when using the RMT and FHT ROI selection methods

Changes in Dorsal Neck Muscle Function in Individuals with Chronic Whiplash-Associated Disorders: A Real-Time Ultrasound Case-Control Study.

PubMed

Peterson, Gunnel; Nilsson, David; Peterson, Simon; Dedering, Åsa; Trygg, Johan; Wallman, Thorne; Peolsson, Anneli

2016-05-01

Impaired neck muscle function leads to disability in individuals with chronic whiplash-associated disorder (WAD), but diagnostic tools are lacking. In this study, deformations and deformation rates were investigated in five dorsal neck muscles during 10 arm elevations by ultrasonography with speckle tracking analyses. Forty individuals with chronic WAD (28 women and 12 men, mean age = 37 y) and 40 healthy controls matched for age and sex were included. The WAD group had higher deformation rates in the multifidus muscle during the first (p < 0.04) and 10th (only women, p < 0.01) arm elevations compared with the control group. Linear relationships between the neck muscles for deformation rate (controls: R(2) = 0.24-0.82, WAD: R(2) = 0.05-0.74) and deformation of the deepest muscles (controls: R(2) = 0.61-0.32, WAD: R(2) = 0.15-0.01) were stronger for women in the control group versus women with WAD, indicating there is altered interplay between dorsal neck muscles in chronic WAD. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Intramuscular pressures in antigravity muscles using gravity-independent, pneumatic hardware.

PubMed

Macias, Brandon R; Minocha, Ranjeet; Cutuk, Adnan A; Hill, James; Shiau, Jonathon; Hargens, Alan R

2008-08-01

Resistive exercise helps prevent muscle atrophy in microgravity, but better exercise equipment is needed. Therefore, the purpose of this study was to determine if a pneumatic, gravity-independent leg-press device (LPD) provides sufficient force to leg musculature. We hypothesized that intramuscular pressure (IMP), a quantitative index of muscle force, is greater in the antigravity superficial posterior and deep posterior compartments than in the non-antigravity anterior compartment during bilateral leg-press exercise. Millar pressure transducers were inserted into the anterior, lateral, superficial posterior, and deep posterior muscle compartments of the left leg of eight healthy subjects (three women, five men). Subjects were supine on the Keiser SX-1, a pneumatic LPD. Then maximal voluntary contraction (MVC) was determined; each subject performed three consecutive voluntary contractions at approximately 18%, 50%, and 100% MVC while continuously measuring IMP. Repeated measures ANOVA were used to determine differences of IMPs between compartments and loads. The magnitudes of IMP (mean +/- SEM) at 18 - 3% (abbreviated approximately 18%), 50%, and 100% MVC in the superficial and deep posterior compartments were significantly greater than that in the anterior compartment during exercise (P < 0.05). Additionally, IMPs in all four compartments significantly rose as resistance increased at approximately 18%, 50%, and 100% MVC (P < 0.05). The LPD provides significantly increased resistance to all four compartments, but with greater loading of the antigravity compartments as compared to the non-antigravity compartment. Since antigravity muscles of the leg are contained primarily in the superficial and deep posterior compartments, the LPD may help prevent muscle atrophy associated with microgravity.

Structural and biochemical characteristics of locomotory muscles of emperor penguins, Aptenodytes forsteri.

PubMed

Ponganis, P J; Costello, M L; Starke, L N; Mathieu-Costello, O; Kooyman, G L

1997-07-01

Structural and biochemical characteristics of the primary muscles used for swimming (pectoralis, PEC and supracoracoideus, SC) were compared to those of leg muscles in emperor penguins (Aptenodytes forsteri). The mass of PEC-SC was four times that of the leg musculature, and mitochondrial volume density in PEC and SC (4%) was two-thirds that in sartorius (S) and gastrocnemius. The differences in muscle mass and mitochondrial density yielded a 2.2-fold greater total mitochondrial content in PEC-SC than leg muscles, which appears to account for the 1.8-fold greater whole-body highest oxygen consumption previously recorded in emperor penguins during swimming compared to walking. Calculation of maximal mitochondrial O2 consumption in PEC-SC and leg muscle yielded value of 5.8-6.9 ml O2 ml-1 min-1, which are similar to those in locomotory muscles of most mammals and birds. A distinct feature of emperor penguin muscle was its myoglobin content, with concentrations in PEC-SC (6.4 g 100 g-1 among the highest measured in any species. This resulted in a PEC-SC O2 store greater than that of the entire blood. In addition, ratios of myoglobin content to mitochondrial volume density and to citrate synthase activity were 4.4 and 2.5 times greater in PEC than in S, indicative of the significant role of myoglobin in the adaptation of muscle to cardiovascular adjustments during diving.

Effect of rubber flooring on dairy cattle stepping behavior and muscle activity.

PubMed

Rajapaksha, Eranda; Winkler, Christoph; Tucker, Cassandra B

2015-04-01

Use of compressible flooring, such as rubber, has increased on dairy farms. Rubber improves locomotion and is well used by cattle in preference experiments that combine walking and standing. Previous work has found that rubber is particularly beneficial for lame animals, perhaps because a softer material is particularly useful when a single hoof is compromised. The goal of this work was to evaluate the effect of flooring while standing, because cattle in freestall housing spend 40 to 50% of their time engaged in this behavior. In a 2 × 2 design, cows (n = 16) were evaluated on 4 standing surfaces that varied in terms of both floor type (concrete or rubber) and presentation [same floor under all 4 legs (all 4 legs on either concrete or rubber) or a rough surface under only one hind leg and the other 3 legs on concrete or rubber] in a crossover design. Surface electromyograms were used to evaluate muscle fatigue, total activity, and movement of muscle activity between legs during 1 h of standing. Muscle fatigue was evaluated in 2 contexts: (1) static contractions when cows continuously transferred weight to each hind leg, before and after 1 h of standing, and (2) dynamic contractions associated with steps during 1 h on treatment surfaces. In addition, stepping rate, time between each consecutive step, and the latency to lie down after testing were measured. No interaction between floor type and presentation was found. Presentation had a significant effect; when one hind leg was on a rough surface, cattle took 1.7 times more steps with this leg and the non-rough hind leg had 1.2 times more muscle activity, compared with when all 4 legs were on the same surface. These changes are consistent with movement away from concrete with protrusions. When standing on rubber, muscle-activity movements among legs remained stable (0.6-0.7 movements per min) over 1 h but increased on concrete (0.6-0.9 movements per min), indicating that, like humans, cattle may sway to counteract

Biochemical response to chronic shortening in unloaded soleus muscles

NASA Technical Reports Server (NTRS)

Jaspers, S. R.; Fagan, J. M.; Tischler, M. E.

1985-01-01

One leg of tail-casted suspended rats was immobilized in a plantar-flexed position to test whether chronic shortening of posterior leg muscles affected the metabolic response to unloading. The immobilized plantaris and gastrocnemius muscles of these animals showed approximately 20 percent loss of muscle mass in contrast to simply a slower growth rate with unloading. Loss of mass of the soleus muscle during suspension was not accentuated by chronic shortening. Although protein degradation in the isolated soleus muscle of the plantar-flexed limb was slightly faster than in the contralateral free limb, this difference was offset by faster synthesis of the myofibrillar protein fraction of the chronically shortened muscle. Total adenine nucleotides were 17 percent lower (P less than 0.005) in the chronically shortened soleus muscle following incubation. Glutamate, glutamine, and alanine metabolism showed little response to chronic shortening. These results suggest that, in the soleus muscle, chronic shortening did not alter significantly the metabolic responses to unloading and reduced activity.

Electrically induced muscle cramps induce hypertrophy of calf muscles in healthy adults.

PubMed

Behringer, M; Moser, M; Montag, J; McCourt, M; Tenner, D; Mester, J

2015-06-01

Skeletal muscles usually cramp at short lengths, where the tension that can be exerted by muscle fibers is low. Since high tension is an important anabolic stimulus, it is questionable if cramps can induce hypertrophy and strength gains. In the present study we investigated if electrically induced cramps (EIMCs) can elicit these adaptations. 15 healthy male adults were randomly assigned to an intervention (IG; n=10) and a control group (CG; n=5). The cramp protocol (CP) applied twice a week to one leg of the IG, consisted of 3x6 EIMCs, of 5 s each. Calf muscles of the opposite leg were stimulated equally, but were hindered from cramping by fixating the ankle at 0° plantar flexion (nCP). After six weeks, the cross sectional area of the triceps surae was similarly increased in both the CP (+9.0±3.4%) and the nCP (+6.8±3.7%). By contrast, force of maximal voluntary contractions, measured at 0° and 30° plantar flexion, increased significantly only in nCP (0°: +8.5±8.8%; 30°: 11.7±13.7%). The present data indicate that muscle cramps can induce hypertrophy in calf muscles, though lacking high tension as an important anabolic stimulus.

Cupiennius salei: biomechanical properties of the tibia-metatarsus joint and its flexing muscles.

PubMed

Siebert, Tobias; Weihmann, Tom; Rode, Christian; Blickhan, Reinhard

2010-02-01

Hunting spiders are well adapted to fast locomotion. Space saving hydraulic leg extension enables leg segments, which consist almost soley of flexor muscles. As a result, the muscle cross sectional area is high despite slender legs. Considering these morphological features in context with the spider's segmented C-shaped legs, these specifics might influence the spider's muscle properties. Moreover, these properties have to be known for modeling of spider locomotion. Cupiennius salei (n = 5) were fixed in a metal frame allowing exclusive flexion of the tibia-metatarsus joint of the second leg (counted from anterior). Its flexing muscles were stimulated supramaximally using needle electrodes. Accounting for the joint geometry, the force-length and the force-velocity relationships were determined. The spider muscles produce 0.07 N cm maximum isometric moment (corresponding to 25 N/cm(2) maximum stress) at 160 degrees tibia-metatarsus joint angle. When overextended to the dorsal limit at approximately 200 degrees , the maximum isometric moments decrease to 72%, and, when flexed to the ventral hinge stop at 85 degrees , they drop to 11%. The force-velocity relation shows the typical hyperbolic shape. The mean maximum shortening velocity is 5.7 optimum muscle lengths per second and the mean curvature (a/F (iso)) of the Hill-function is 0.34. The spider muscle's properties which were determined are similar to those of other species acting as motors during locomotion (working range, curvature of Hill hyperbola, peak power at the preferred speeds), but they are relatively slow. In conjunction with the low mechanical advantage (muscle lever/load arm), the arrangement of three considerably actuated joints in series may nonetheless enable high locomotion velocities.

Validity of real-time ultrasound imaging to measure anterior hip muscle size: a comparison with magnetic resonance imaging.

PubMed

Mendis, M Dilani; Wilson, Stephen J; Stanton, Warren; Hides, Julie A

2010-09-01

Clinical measurement, criterion standard. To investigate the validity of real-time ultrasound imaging (USI) to measure individual anterior hip muscle cross-sectional area. The hip flexor muscles are important for hip joint function and could be affected by joint pathology or injury. Objectively documenting individual anterior hip muscle size can be useful in identifying muscle size asymmetry and monitoring treatment efficacy for patients with hip problems. USI offers a novel method of measuring individual muscle size in the clinic, but its validity in measuring the anterior hip muscles has not been investigated. Nine healthy participants (5 males, 4 females) underwent imaging of their iliopsoas, sartorius, and rectus femoris muscles with USI and magnetic resonance imaging. Bilateral muscle cross-sectional areas were measured on images from both modalities. There was no significant difference (P>.05) in mean cross-sectional area measurements from USI and magnetic resonance imaging for each muscle. Agreement between measurements was high for the iliopsoas (left: intraclass correlation coefficient [ICC3,1] = 0.86; 95% confidence interval [CI]: 0.51, 0.97; right: ICC3,1 = 0.88; 95% CI: 0.57, 0.97), sartorius (left: ICC3,1 = 0.82; 95% CI: 0.41, 0.96; right: ICC3,1 = 0.81; 95% CI: 0.39, 0.95), and rectus femoris (left: ICC3,1 = 0.85; 95% CI: 0.49, 0.96; right: ICC3,1 = 0.89; 95% CI: 0.61, 0.97). Reliability of measuring each muscle with USI was high between 2 trials (ICCs3,1 = 0.84 to 0.94). USI is a valid measure of iliopsoas, sartorius, and rectus femoris muscle size in healthy people, as long as a strict measurement protocol is followed.

Recent advances in ultrasound-triggered therapy.

PubMed

Yang, Chaopin; Li, Yue; Du, Meng; Chen, Zhiyi

2018-04-27

As a non-invasive and real-time diagnostic technique, ultrasound has provided a novel strategy for targeted treatment. With the rapid development of ultrasonic technique and ultrasound contrast agents (UCAs), spatiotemporally controllable application of ultrasound with or without UCAs makes it possible for site-specific delivery of therapeutic agents and targeted modulation with minimal side effects, which indicated a promising therapy in clinical use. This review will describe the main mechanism of targeted therapy induced by ultrasound briefly, then focus on the current application of ultrasound mediated targeted therapy in various fields including tumour, cardiovascular disease, central nervous system, skeletal muscle system diseases and stem cells therapy. In addition, ongoing challenges of ultrasound-mediated targeted therapy for further research and its clinical use are reviewed.

Energy Metabolism during Repeated Sets of Leg Press Exercise Leading to Failure or Not