Trends in Selected Kinematic and Myoelectric Variables Associated with Learning a Novel Motor Task

Cinematographic and electromyographic methods were used to coordinate the collection of kinematic and myoelectric data on 41 male subjects. The novel motor task consisted of propelling a four-wheeled carriage along a level aluminum track to a criterion velocity by a knee extension movement. Mean performance scores demonstrated that a significant amount of learning took place over 21 trials. The finding of learning over practice provided a basis by which changes in the kinematic and myoelectric variables were analyzed. Statistical analysis consisted of a One-Sample Hotelling's T2 Test and Trend Analysis using a Multiple Regression Program. Data were collected on trials 1, 2, 6, 15, and 21. Results revealed that: (1) both knee joint and ankle joint angular velocities at release followed the same trend as performance scores; (2) two myotemporal variables had no significant trends on the four muscles under investigation; and (3) two knee flexors had linear trends and two knee extensors had cubic trends on the variable maximum integrated electromyographic (Iemg) amplitude. It was concluded that: (1) trends of joint angular velocities over practice more closely resembled the performance score trends than did myoelectric activity; (2) when myotemporal changes are not evident over practice, changes in maximum Iemg amplitude of muscles are responsible for increasing performance proficiency; and (3) if performance demands an increase in joint angular velocity, agonistic as well as antagonistic myoelectric activity will increase in muscles which act at the joint.