EXSS2025 Lecture Notes - Lecture 10: Motor Unit, Motor Neuron, Brainstem

• School: University of Sydney
• Department: Exercise and Sport Science
• Course: EXSS2025
• Professor: Ross Sanders

Document Summary

Neural networks from central area of brainstem > spinal column > muscle recruitment. Efferent and afferent activity integrating with each other and responding to stimuli. Muscular movement is the end result of neural processing/activity. Need regulation as muscle force is limited - fatigue. Consist of an efferent motor neuron and the muscle fibres it innervates. Thousands of fibres in smaller numbers of motor units: properties of motor units/muscle composition. Due to different fibre types - slow (type 1), fast twitch fatigue resistant (type 2a), fast twitch fatigable (type 2b) Motor unit size principle: motor units are recruited in a particular order - increasing force with motor unit size. S(cid:373)all mu: little force productio(cid:374), type 1 s, precisio(cid:374), less e(cid:374)ergy co(cid:374)su(cid:373)ptio(cid:374) Large mu: larger force, quick fatigue, use a lot more energy (predatory, escape) Mu force increases non linearly with level of recruitment.