ENS 401A Study Guide - Midterm Guide: Motor Skill, Stretching, Iliopsoas
1 Mar 2017
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Describe the physical changes that occur within nerves and within muscles that are held for prolonged periods) in shortened and lengthen positions - include consequences. Prolonged immobilization / lack of use (module 1, slide 4) Muscles quickly shorten (e. g. 2-4 weeks in passively, shortened positions. Results in loss of sarcomere number muscle adapts to become stronger in the shortened position muscle is weaker at normal, resting length (100%) In the antagonist muscle, number of sarcomeres increases muscle is weaker at normal resting length (100%) Shortened muscles = lowered activation thresholds for action potentials (aps) hypertonicity = greater state of tension. Requires smaller neural stimulus to generate ap (in neuron) As muscles normally co-activate at joint (i. e. movement), hypertonic muscles fire pre-maturely = inhibition of muscle action via reciprocal inhibition, which contributes to progressive muscle weakening. Example: tight hip flexors shut down / weaken gluteus maximus. Describe muscle soreness, causes, overreaching, and overtraining syndrome. Acute muscles soreness (module 1, slide 28)
