Are there sex differences in muscle coordination of the upper girdle during a sustained motor task?

Abstract Experimental studies and EMG collections suggest that a specific strategy of muscle coordination is chosen by the central nervous system to perform a given motor task. A popular mathematical approach for solving the muscle recruitment problem is optimization. Optimization-based methods minimize or maximize some criterion (objective function or cost function) which reflects the mechanism used by the central nervous system to recruit muscles for the movement considered. The proper cost function is not known a priori, so the adequacy of the chosen function must be validated according to the obtained results. In addition of the many criteria proposed, several physiological representations of the musculotendon actuator dynamics along with different musculoskeletal models can be found in the literature, which hinders the selection of the best neuromusculotendon model for each application. Seeking to provide a fair base for comparison, this study measures the efficiency and accuracy of: i) four different criteria; ii) one static and three physiological representations of the musculotendon actuator dynamics; iii) a synergy-based method; all of them within the framework of inverse-dynamics based optimization. Motion/force/EMG gait analyses were performed on ten healthy subjects. A musculoskeletal model of the right leg actuated by 43 Hill-type muscles was scaled to each subject and used to calculate joint moments, musculotendon kinematics and moment arms. Muscle activations were then estimated using the different approaches, and these estimates were compared with EMG measurements. Although similar results were obtained with all the methods, it must be pointed out that a higher complexity of the method does not guarantee better results, as the best correlations with experimental values were obtained with two simplified approaches.

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Sex Differences in Maintaining the Requested Handgrip Force Enhanced by Auditory or Visual Feedback

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17145158 ◽

2020 ◽

Vol 17 (14) ◽

pp. 5158

Author(s):

Jacek Tarnas ◽

Rafał Stemplewski ◽

Piotr Krutki

Keyword(s):

Sex Differences ◽

Motor Learning ◽

Visual Feedback ◽

Motor Task ◽

Motor Tasks ◽

Auditory Displays ◽

Main Effect ◽

Simple Motor Task ◽

And Performance ◽

Mixed Groups

Thus far, the differences in effect of auditory or visual feedback in motor learning have presented results derived from mixed groups and sex differences have not been considered. However, perception and processing of auditory stimuli and performance of visual motor tasks appear to be sex-related. The purpose of this study was to investigate the learning of the simple motor task of maintaining a requested handgrip force in separate male and female groups. A total of 31 volunteers (15 males, 16 females) were randomly assigned to one of four experimental groups with defined sex and training conditions (audio or visual feedback). Participants performed training sessions over a period of six days, for which auditory or visual feedback was provided, and the effectiveness of both types of signals was compared. The evident learning effect was found in all groups, and the main effect of sex was significant among visual groups in favor of the males (p < 0.05). On the other hand, the main effect of feedback conditions was found to be significant among females, beneficially in the case of auditory displays (p < 0.05). The results lead to the conclusion that an equal number of males and females in mixed experimental groups may be supportive to obtain reliable results. Moreover, in motor-learning studies conducted on females only, a design including auditory feedback would be more suitable.

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Biomechanical analysis for the study of muscle contributions to support load carrying

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/09544062jmes1559 ◽

2010 ◽

Vol 224 (6) ◽

pp. 1287-1298 ◽

Cited By ~ 3

Author(s):

A Selk Ghafari ◽

A Meghdari ◽

G R Vossoughi

Keyword(s):

Lower Extremity ◽

Functional Performance ◽

Sagittal Plane ◽

Motor Task ◽

Load Carriage ◽

Biomechanical Analysis ◽

Dynamics Simulation ◽

Experimental Investigations ◽

Muscle Coordination ◽

Individual Muscle

The objective of this study was to quantify individual muscle function differences between level walking and backpack load carriage at the same speed by using a muscle-actuated forward dynamics simulation. As experimental investigations have revealed that backpack loads of up to 64 per cent of an individual's body mass have little effect on the sagittal plane gait kinema-tics, further biomechanical analyses are necessary to investigate the contributions of individual muscle coordination strategies to achieve a given motor task by mechanical power generation, absorption, and transference to each body segment. A biomechanical framework consisting of a musculoskeletal model actuated by 18 Hill-type musculotendon actuators per leg and a non-linear suspension model of a backpack equipped with shoulder straps and waist belt was utilized to perform the simulation study. An optimization framework based on minimizing the muscle energy consumption was employed to investigate the muscle load sharing mechanism during simulation of the movements under investigation. Estimated muscle activations were in good agreement with the salient features of the corresponding electromyographic recordings of the major lower extremity muscles. Furthermore, simulated joint kinematics closely tracked experimental quantities with root-mean-squared errors less than one degree. Segmental power analysis for individual muscles was performed to elucidate the muscle's contribution to body support and forward progression in load carriage. Comparing muscle functions during the activities under investigation illustrated the different functional performance of the lower extremity muscles and the capability of the joints and segments to reduce the transmission of force during load carriage.

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Age and Sex Differences in Learning and Performance of an Arm Speed Motor Task

Research Quarterly American Association for Health Physical Education and Recreation ◽

10.1080/10671188.1968.10616559 ◽

1968 ◽

Vol 39 (3) ◽

pp. 428-431 ◽

Cited By ~ 1

Author(s):

Richard B. Alderman

Keyword(s):

Sex Differences ◽

Motor Task ◽

And Performance ◽

Age And Sex ◽

Learning And Performance

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SEX DIFFERENCES IN SELF-REPORTED RIGHT-LEFT CONFUSION BY ADULTS: A ROLE FOR SOCIAL DESIRABILITY?

Social Behavior and Personality An International Journal ◽

10.2224/sbp.1993.21.4.327 ◽

1993 ◽

Vol 21 (4) ◽

pp. 327-332 ◽

Cited By ~ 11

Author(s):

Robert J. Williams, ◽

Karen Standen ◽

Lina A. Ricciardelli

Keyword(s):

Sex Differences ◽

Social Desirability ◽

Negative Correlation ◽

Motor Performance ◽

Discrimination Task ◽

Motor Task ◽

Significant Negative Correlation ◽

Self Reports ◽

Males And Females

Self-reports of difficulty in discriminating right from left (R/L), a measure of the influence of social desirability, and motor performance on a discrimination task (a map test) were compared in males and females. Significantly more females reported some degree of R/L confusion and there was a significant negative correlation between females' self-reports and social desirability scores. No such relationship was found for men's scores and no sex differences were evident during performance on the motor task.

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