Question

Experiment: students will use a hand dynamometer to measure a subject’s grip strength for dominant and non-dominant forearms and the relative strength and electrical activity of each forearm will be compared to its circumference. Recordings of prolonged grip strength and forearm EMG activity will determine the rate of fatigue in the dominant and non-dominant forearms:

Question: Connect how fast/slow twitch types can be correlated to max force and time to fatigue for dominant/non-dominant arm.

Answer 1

Maximum force is higher in dominant arm and the time of fatigue is faster and the dominant arm is also associated with fast-twitch.  Non-dominant arm is  associated with slow-twitch and have slow fatigue time.

Explanation

Slow-twitch and fast-twitch are the 2 types of skeletal muscle twitches.

a) Slow-twitch (type I ) - These fibers have lowest contractile speed,smallest area of crossection, highest aerobic capacity and lowest aneorobic capacity . Due to the presence of blood vessels, they are red in colour.

b) Fast-twitch (type II ) - These fibers have fastest contractile speed , largest area of crossection , lowest aerobic capacity and highest aneorobic capacity . They contracted slowly. They are able to hold steady paced twitch without fatigue for a long period. They create fuel by aneorobic metabolism.

Dominant arm is stronger than that of non-dominant arm. The strength of 2 arms are different. So , both of them have difference in fatigue time. This is due to the increasing diameter of each muscle fibers in dominant arm ,rather than increasing number of muscle fibers. The voluntary activation and neuromuscular propagation of non-dominant arm is lesser than that of dominant arm .

Both fast-twitch and slow-twitch produce same amount of force per concentration. But fast-twitch fatigue faster than slow-twitch . And they have maximum force and faster fatigue time . This is in turn associated with dominant arm.

Slow-twitch is associated with non-dominant arm and they show slow fatigue time with maximum force smaller than dominant arm.