UNIT 4 - JOINTS CONT. Flashcards
Define isotonic contractions
those which cause the muscle to change length as it contracts and moves a body part
List the two types isotonic contraction
concentric and eccentric
define concentric contraction
contractions that cause the muscle to shorten as it contracts. eg - bending elbow from straight to fully flexed causes concentric contraction of biceps.
most common type
define eccentric contraction
opposite of concentric. causes muscle to lengthen as it contracts. eg - lowering dumbell. muscle still contracts to hold weight down but is still lengthening
define isometric contractions
occur when there is no change in the length of the contracting muscle; when carrying an object in front of the body. the weight pulls the arms down but muscles have to contract to hold the weight at the sesame level.
eg - when you grip onto something like a tennis racket. hand muscles have to contract to hold it.
when is the muscle at optimum length?
when maximum isometric force can be produced
define isokinetic contractions
muscle changes length during contractions. produce movement at a constant speed. difficult to measure this contraction, but there are isokinetic dynamometers. an example is during breaststroke
define reciprocal inhibition
a neuromuscular reflex that inhibits opposing muscles to enable voluntary movement. the concept that muscles work in pairs or groups (agonist and antagonist)
what causes DOMS?
results primarily from exxentric muscle action and is associated with structural muscle damage; inflammitory reactions in the muscle; overstretching and overtraining
how is DOMS prevented?
by reducing the eccentric component of muscle actions during early training. start training at low intensity and gradually increase. warm up and cool down.
what produces DOMS?
small tears
Small pressure causing fluid retentions in surrounding tissue
Muscle spasms
Overstretching muscle
Accute inflammation
Alteration in the cells’ mechanism calcium regulation
