KP351 Lecture Notes - Lecture 2: Electromyography, Motor Unit, Alpha Motor Neuron

• School: WLU
• Department: Kinesiology & Physical Education
• Course: KP351
• Professor: Stephen Perry

Document Summary

Cross-bridge theory of muscle contraction (emg reading 1 figures 3. 8-3. 10) Net muscle actions (types of muscular contraction) (emg reading 1 pg. Isometric: net muscle action is 0, plank, wall sit. Concentric: net muscle action is +, bicep curl up. Eccentric: net muscle action is - , releasing bicep curl slowly. Muscular activity (electromyography (emg)) (emg reading 2 pg. Electromyography (muscle activity) provides information about control and execution of voluntary (and reflexive) movements. (emg reading 2 figure 8. 1) Provides info about control and execution of voluntary and reflexive movements: ex. when you block off sensory info. Mus(cid:272)le fi(cid:271)re a(cid:272)tio(cid:374) pote(cid:374)tial: what"s happe(cid:374)i(cid:374)g i(cid:374) the fi(cid:271)re. Co(cid:373)(cid:271)o of the alpha (cid:373)otor (cid:374)euro(cid:374) (cid:894)fro(cid:373) cns(cid:895) effere(cid:374)t (cid:374)euro(cid:374) a(cid:374)d its asso"d (cid:373)us(cid:272)le fi(cid:271)res. Motor u(cid:374)it: alpha (cid:373)otor (cid:374)euro(cid:374) + asso"d (cid:373)us(cid:272)le fi(cid:271)res. Fire 1 neuron = activate set of fibres. Fine control muscle: 100-500 muscle fibres / 1 motor neuron (mf/m. Innervation ratio in the thousands 10 50 000 mf/mn: ex. leg muscles.