KINE MODULE 4: Muscle Exercise Physiology

Type 1 Muscle fibers are more for what type of exercise?

long/endurance (high aerobic endurance)

Type II Muscle Fibers are more for what?

Powerful, fast movements (poor aerobic endurance)

When do muscle fibers reach peak power?

at roughly 20% of peak force

Which muscle fiber type produces the MOST power?

Type IIx

Recruitment Order of Muscle Fibers

type I (low-force generating), type IIa, type IIx (force demand increases)

Isometric Contraction

No change in muscle length

Concentric Contraction

shortening of muscle

• most common type

Eccentric Contraction

lengthening of muscle

• most damaging

As force increases , velocity ?

decreases

What are the FIVE steps of the Sensory-Motor Integration

1. Stimulus is sensed by sensory receptor

2. Sensory AP sent on sensory neurons to CNS

3. CNS interprets sensory info, sends response

4. Motor AP sent out on a motor neurons

5. Arrives at skeletal muscle and response occur

reflexs are __________ responses that _____ change

preprogrammed responses that dont change

Muscle Fatigue

muscle cannot maintain power output that you are wanting to maintain

• decrease in muscle force generation and shortening velocity

What causes muscle fatigue ?

disturbances in the CNS and peripheral factors within the skeletal muscle

anaerobic glycolysis

higher intensities (H+ accumulation)

The cause of fatigue is NOT ??

lactate

does ATP-PC recycles itself

true

PCr depletion limits ability to replace what?

ATP

glycogen is replaced in

skeletal muscle and liver

muscle glycogen depletion + hypoglycemia =

fatigue

“hitting the wall” can be when

the muscle glycogen is depleted causing the exercise to be harder

Reactive Oxygen Species =

impaired mitochondrial functions which decreases ATP formation through oxidative pathways

Humidity Increase =

availabilty to exercise decreases

Critical Power

highest intensity to maintain for 30 minutes before fatiguing

• link between optimal performance and fatigue

Muscle Soreness hits hard around ________ hours post-exercise

48

DOMS is

delayed-onset muscle soreness

Muscle soreness and DOMS is caused by

eccentric contractions