KIN 100 1st Edition Lecture 23 Continued from 4/10■ Triphasic pattern● initial burst of agonist activity● burst in antagonist muscle● second burst of agonist muscle■ in general, larger muscle size correlates with greater muscular strength○ Nervous system and strength training■ to increase strength● 1. activate more motor units● 2. increase motor unit firing rate● 3. decrease antagonist activity○ bilateral control of muscular strength■ activate similar muscles on both sides of body■ crossed extension reflex○ testing muscular strength■ muscular force, left leg only● 50 units■ right leg only● 50 units■ both legs● 75 units■ unilateral- on leg■ bilateral- both legs● less than sum of both unilateral contractions● bilateral deficit ○ disinhibition through training■ bilateral/unilateral sum strength■ 3 groups of rowers● club- .5● national class rowers~.75● elite rowers ~>1 greater muscular strength bilateral than unilateral○ fatigue■ failure to continue workThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.■○ contractile failure○ biochemical changes○ ATP declines○ H+ increases● Neural aspects of fatigue○ motor unit firing rate■ decreases due to fatigue○ skin receptors- inhibition■ hypoxia● prolonged contraction of muscle cuts off blood flow-> decrease in O2 level■ chemical release○ Descending central drive○ MEP (using TMS)■ before fatigue > after fatigue○ Vision■ Visual acuity● sharpness of vision● static, no movement○ eye chart○ best with object in center of retina○ high light conditions● dynamic (DVA)○ discriminate moving object○ baseball batters■ training to increase visual acuity● accommodation training● tracking○ oculomotor system○ smooth pursuit movement■ smooth eye movement○ saccadic movementsTimestrength■ more jerky■ quick eye movements● eye-head coordination○ VOR- vestibulo-ocular reflex■ semicircular canals-> vestibular nucleus->oculomotor neurons-> eye○ improves with practice■ visual dominance● alignment test○ unilaterals (ex. right handed and right eyed)○ cross dominant (ex. right eyed, left handed)○ unilaterals: better performance■ depth perception● requires binocular vision● static vs dynamic■ field of vision● area seen w/out moving eyes● peripheral vision○ horizontal and vertical■ figure-ground perception● distinguish object from background● aided by familiarity○ view arena before game■ one possible advantage of playing at home
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