Human Muscular Contraction: Role of the Mechanical Components (Electromyography, Series Elasticity)

A regression model was developed for predicting torque output for human muscular contraction during a uniplanar arm extension maneuver. The predictor variables used in the model were developed during a series of 3 experiments, and represented the basic electrical and mechanical properties of contracting muscle. In experiment 1, the relationship between the response of the series elastic component (SEC) and activation of the muscle was elucidated. This relationship was used to predict the response of the SEC during the various conditions of contraction in Experiment 4, for input into the regression equations. In Experiments 2 and 3, the maximum 3-dimensional torque-velocity-length volume was developed for each subject. Individual trial torque-velocity-length volumes were taken as a percentage of the maximum volume for each contraction trial in Experiment 4. These ratios were used in the regression analysis to represent the properties of the contractile component. The history of the active state was represented in the regression equations by the slope of the integrated EMG curve calculated to peak jerk and to peak torque. The ability of these variables to predict the torque output was tested over 27 conditions of contraction in Experiment 4. Three loads placed on the system, three starting muscle lengths, and three velocities of contraction were manipulated. It was shown that when the variables representing the appropriate electrical and mechanical properties of muscle were entered into a regression model, a large population of variance could be accounted for in predicting the mechanical output of the system. The best predictors were the ratios representing the torque-velocity-length properties. It was hypothesized that these properties not only represented the input from the contractile element but were also reflective of the inputs from the series elastic element and the active state due to their link to cross-bridge formation.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physical Education

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Robertson, Richard Niell

• Education, Physical

Identifier

(UMI)AAI8521870

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/71875