Types of Muscle Contractions

What is Contraction

• Contraction of a muscle does not necessarily mean shortening, but rather that tension has been generated

What are 2 main types of Muscle contraction

Isotonic & Isometric

What is isotonic Muscle contraction

• muscle changes length as it contracts and moves a load

Two types of isotonic contractions:  concentric and eccentric

What is Concentric Contraction

muscle shortens as it contracts

Ex. Curl-up - rectus abdominus shortens when curling upwards

Squat - coming up from a sitting position, to a standing position your quad muscles shorten to straighten your knee

What is Eccentric Contraction

• muscle contracts as it lengthens 

E.x Curl-up - rectus abdominus lengthens, when lying back down after a curl-up (abs are still contracting so that you don’t flop back down)

Squat - quad muscles lengthen as you go down in a squat/sitting position, but are contracting to counteract gravity (so you won’t fall)

What is Isometric Contraction

• muscle has no change in length as it contracts

  • Tension continues to increase, but muscle neither shortens or lengthens

• Stabilizing muscles maintain posture and hold joints in stationary position while other movement occurs

e.x

• Trying to move a load that is too heavy for you i.e pushing against a brick wall

• Holding yourself in a plank position