scholarly journals The energetic basis for smooth human arm movements

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Jeremy D Wong ◽  
Tyler Cluff ◽  
Arthur D Kuo
Keyword(s):  
Energy Expenditure ◽  
Energy Cost ◽  
Muscle Force ◽  
Force Production ◽  
Metabolic Energy ◽  
Reaching Movements ◽  
Human Arm ◽  
The Central Nervous System ◽  
Muscle Force Production ◽  
Human Arm Movements

The central nervous system plans human reaching movements with stereotypically smooth kinematic trajectories and fairly consistent durations. Smoothness seems to be explained by accuracy as a primary movement objective, whereas duration seems to economize energy expenditure. But the current understanding of energy expenditure does not explain smoothness, so that two aspects of the same movement are governed by seemingly incompatible objectives. Here we show that smoothness is actually economical, because humans expend more metabolic energy for jerkier motions. The proposed mechanism is an underappreciated cost proportional to the rate of muscle force production, for calcium transport to activate muscle. We experimentally tested that energy cost in humans (N=10) performing bimanual reaches cyclically. The empirical cost was then demonstrated to predict smooth, discrete reaches, previously attributed to accuracy alone. A mechanistic, physiologically measurable, energy cost may therefore explain both smoothness and duration in terms of economy, and help resolve motor redundancy in reaching movements.

scholarly journals The energetic basis for smooth human arm movements

2020 ◽  
Author(s):  
Jeremy D Wong ◽  
Tyler Cluff ◽  
Arthur D Kuo
Keyword(s):  
Energy Cost ◽  
Muscle Force ◽  
Force Production ◽  
Excess Energy ◽  
Metabolic Energy ◽  
Reaching Movements ◽  
Human Arm ◽  
The Central Nervous System ◽  
Muscle Force Production ◽  
Human Arm Movements

AbstractThe central nervous system plans human reaching movements with stereotypically smooth kinematic trajectories and fairly consistent durations. Smoothness seems to be explained by accuracy as a primary movement objective, whereas duration seems to avoid excess energy expenditure. But energy does not explain smoothness, so that two aspects of the same movement are governed by seemingly incompatible objectives. Here we show that smoothness is actually economical, because humans expend more metabolic energy for jerkier motions. The proposed mechanism is an underappreciated cost proportional to the rate of muscle force production, for calcium transport to activate muscle. We experimentally tested that energy cost in humans (N=10) performing bimanual reaches cyclically. The empirical cost was then demonstrated to predict smooth, discrete reaches, previously attributed to accuracy alone. A mechanistic, physiologically measurable, energy cost may therefore unify smoothness and duration, and help resolve motor redundancy in reaching movements.

Eccentric exercise in rehabilitation: safety, feasibility, and application

2014 ◽  
Vol 116 (11) ◽  
pp. 1426-1434 ◽  
Author(s):  
Paul LaStayo ◽  
Robin Marcus ◽  
Lee Dibble ◽  
Fernando Frajacomo ◽  
Stan Lindstedt
Keyword(s):  
Muscle Atrophy ◽  
Eccentric Exercise ◽  
Energy Cost ◽  
Muscle Force ◽  
Force Production ◽  
Dual Phase ◽  
Clinical Considerations ◽  
Review Reports ◽  
Muscle Force Production ◽  
Exercise Countermeasures

This nonexhaustive mini-review reports on the application of eccentric exercise in various rehabilitation populations. The two defining properties of eccentric muscle contractions—a potential for high muscle-force production at an energy cost that is uniquely low—are revisited and formatted as exercise countermeasures to muscle atrophy, weakness, and deficits in physical function. Following a dual-phase implementation, eccentric exercise that induces rehabilitation benefits without muscle damage, thereby making it both safe and feasible in rehabilitation, is described. Clinical considerations, algorithms of exercise progression, and suggested modes of eccentric exercise are presented.

Does Raising Morning Rectal Temperature to Evening Levels Offset the Diurnal Variation in Muscle Force Production?

2013 ◽  
Vol 30 (4) ◽  
pp. 486-501 ◽  
Author(s):  
Ben J. Edwards ◽  
Samuel A. Pullinger ◽  
Jonathan W. Kerry ◽  
William R. Robinson ◽  
Tom P. Reilly ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Rectal Temperature ◽  
Muscle Force ◽  
Force Production ◽  
Muscle Force Production

Muscle force production and functional performance in spastic cerebral palsy: Relationship of cocontraction

2000 ◽  
Vol 81 (7) ◽  
pp. 895-900 ◽  
Author(s):  
Diane L. Damiano ◽  
Tracy L. Martellotta ◽  
Daniel J. Sullivan ◽  
Kevin P. Granata ◽  
Mark F. Abel
Keyword(s):  
Cerebral Palsy ◽  
Muscle Force ◽  
Functional Performance ◽  
Force Production ◽  
Spastic Cerebral Palsy ◽  
Relationship Of ◽  
Muscle Force Production

Single-Use Versus Multiple-Use Electrodes for Sensory and Motor Threshold Amplitudes and Muscle Force Production

2013 ◽  
Vol 5 (3) ◽  
pp. 123-128
Author(s):  
David O. Draper ◽  
Lucia Maloy ◽  
J. Ty Hopkins ◽  
A. Wayne Johnson ◽  
Dennis Eggett ◽  
...  
Keyword(s):  
Muscle Force ◽  
Force Production ◽  
Multiple Use ◽  
Motor Threshold ◽  
Single Use ◽  
Muscle Force Production

scholarly journals Effect of Fatigue Protocols on Upper Extremity Neuromuscular Function and Implications for Ulnar Collateral Ligament Injury Prevention

2019 ◽  
Vol 7 (12) ◽  
pp. 232596711988887 ◽  
Author(s):  
Toufic R. Jildeh ◽  
Kelechi R. Okoroha ◽  
Joseph S. Tramer ◽  
Jorge Chahla ◽  
Benedict U. Nwachukwu ◽  
...  
Keyword(s):  
Systematic Review ◽  
Injury Prevention ◽  
Upper Extremity ◽  
Muscle Force ◽  
Force Production ◽  
Ulnar Collateral Ligament ◽  
Neuromuscular Function ◽  
Inclusion Criteria ◽  
Collateral Ligament ◽  
Muscle Force Production

Background: As the incidence of overuse injuries to the medial elbow in overhead athletes continues to rise, recent evidence suggests a link between these injuries and alterations in biomechanics produced by athlete fatigue. Previous studies have evaluated the effect of fatigue on elbow injuries using a wide array of fatigue protocols/athletic tasks, and, as a consequence, the results have been heterogeneous. Purpose: To determine whether there is a uniform alteration in neuromuscular function or biomechanics as the overhead athlete fatigues. Furthermore, this study sought to determine whether player fatigue should be accounted for in ulnar collateral ligament (UCL) injury prevention programs. Study Design: Systematic review. Methods: A systematic review of the literature using PubMed and MEDLINE databases was performed. Keywords included fatigue, upper extremity, baseball, pitcher, throwing, and muscle activity. Inclusion criteria consisted of original research articles in the English language involving healthy athletes, use of fatigue protocols, and the evaluation of at least 1 upper limb biomechanical variable. Results: A total of 35 studies involving 644 athletes (90 females, 554 males; mean age, 20.2 years) met the inclusion criteria. General fatigue protocols were used in 2 investigations, peripheral protocols were used in all 35 studies, and 5 different athletic tasks were studied (simulated baseball game, overhead throwing, high-effort swimming, simulated tennis game, and overhead serving). There was a uniform decrease in muscle force production and proprioception in athletes after completing a fatigue protocol. However, there was no consistency among studies when evaluating other important upper limb biomechanical factors. The fatigue protocols did not consistently produce statistically significant changes in elbow torque, pitching biomechanics, or ball velocity. Conclusion: A uniform decrease in muscle force production and proprioception was found after fatigue protocols; however, a majority of fatigue protocols published in the current literature are inconsistently measured and produce heterogeneous results. Therefore, currently, no recommendations can be made for changes in UCL injury prevention training programs to account for potential effects of fatigue. The effect of muscle force production and proprioception on upper extremity injuries should be evaluated in future studies.

scholarly journals Energetic consequences of using a prosthesis with adaptive ankle motion during slope walking in persons with a transtibial amputation

2013 ◽  
Vol 38 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Benjamin J Darter ◽  
Jason M Wilken
Keyword(s):  
Mechanical Properties ◽  
Energy Expenditure ◽  
Energy Cost ◽  
Metabolic Energy ◽  
Prosthetic Design ◽  
Transtibial Amputation ◽  
Ankle Motion ◽  
Technological Advances ◽  
Walking Difficulty ◽  
Metabolic Energy Expenditure

Background:Technological advances in prosthetic design include the use of microprocessors that adapt device performance based on user motion. The Proprio ankle unit prepositions the foot to adjust for walking on slopes and increases foot clearance during swing to minimize gait deviations.Study design:Comparative analysis.Objectives:To investigate the effect of a prosthesis with adaptive ankle motion on physiological gait performance during slope walking.Methods:Six persons with a unilateral transtibial amputation completed treadmill walking tests at three slopes (−5°, 0°, and 5°). The participants were tested wearing a customary device, active Proprio (Pon), and an identical inactivated Proprio (Poff).Results:Metabolic energy expenditure, energy cost for walking, and rating of walking difficulty were not statistically different between the Pon and Poff for all tested slopes. However, for slope descent, energy expenditure and energy cost for walking improved significantly by an average of 10%–14% for both the Pon and Poff compared to the customary limb. Rating of walking difficulty also showed an improvement with slope descent for both the Pon and Poff compared to the customary device. An improvement with slope ascent was found for Pon compared to the customary limb only.Conclusions:Adaptive ankle motion provided no meaningful physiological benefit during slope walking. The Proprio was, however, less demanding than the customary device for slope descent. Differences in the mechanical properties of the prosthetic feet likely contributed to the changes.Clinical relevanceWhile the adaptive ankle motion did not affect metabolic energy expenditure or energy cost for walking, the results suggest close attention should be paid to the mechanical properties of the foot component. Assessment of gait on nonlevel surfaces is recommended to better understand the implications of different prosthetic design features.

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