Muscle Contractions

Question 1

contractions can occur when

Answer 1

muscle is shortening, remaining the same length or lengthening
-can only pull one direction, and can’t push

Question 2

concentric contraction

Answer 2

muscle force is sufficient to overcome a resistance and move the body segment
-shortening of the muscle (muscle is causing the movement)

Question 3

Eccentric

Answer 3

muscle lengthens as it gives in to an external force that is greater than the contractile force it is exerting
-muscle is lengthening, but trying to stay short
-resisting an outside force

Question 4

isometric contraction

Answer 4

“equal length”, no movement
-tension in the muscle without any appreciable change in length
occurs under 2 conditions:
1. antagonistic muscles contract with equal strength
2. muscle is held against another force

Question 5

isotonic

Answer 5

equal tension and tension remains constant while muscle shortens or lengthens (concentric or eccentric)

Question 6

isokinetic

Answer 6

“equal speed”
-maximum muscle effort at same speed
-form of strength testing

Question 7

influence of gravity

Answer 7

-horizontal motion is not affected by gravity
-lifting against gravity is a concentric contraction of the agonist
-slower lowering with gravity is an eccentric contraction of the same muscle

Question 8

a forceful downward motion uses antagonist muscles is a _____

Answer 8

concentric contraction
-gravitational pull is being exceeded