Choose best answer 1. When a healthy but previously sedentary 30-year-old person
ID: 3524801 • Letter: C
Question
Choose best answer
1. When a healthy but previously sedentary 30-year-old person trains with cardiorespiratory endurance activities for 4-6 months, what is the typical improvement in VO2max (relative to the pretraining value)?
a. 0-10%.
b. 10-30%.
c. 10-30%.
d. 80-100%.
2. The purpose of the skeletal muscle fiber's sodium-potassium pump is to:
a. initiate a muscle action potential to cause contraction
b. terminate the muscle action potential to cause relaxation
c. maintain the concentrations of sodium and potassium inside and outside of muscle fibers
d. regulate the calcium concentration inside and outside of fibers by exchanging calcium for sodium and potassium
3. When both Runner A and Runner B run at 188 m/min (7 mph), the VO2 of Runner a is 45 mL/kg/min and the VO2 of Runner B is 43 mL/kg/min. From this information only, it can be correctly concluded that:
a. The mechanical efficiency of Runner B is greater than the mechanical efficiency of Runner A during running at 188 m/min.
b. Runner B is more economical than Runner A when running at 188 m/min.
c. Runner B is a better runner than Runner A.
d. All of these.
4. What number of ATP molecules is/are used in a single, normal crossbridge cycle during concentric contraction of a muscle fiber?
a. 0
b. 1
c. 2
d. 3
Explanation / Answer
Ans : 1 , correct option will be 10- 30% it will be because of adaptation of heart and skeletal muscles. Exercise training will increases size of heart and skeletal muscles so there will be an increase in the VO2 max and exercise capacity of the person.
Ans : 2 , C is the correct option, as the purpose of skeletal muscle's sodium-potassium pump is to maintain sodium and potassium concentration to help in maintaining resting membrane potential.
Ans :3 , D is the correct option, as runner B has less vO2 max for same pace than runner A so his efficiency is better and he is economically better as well.
Ans : 4, B is the correct answer, one molecule of ATP is hydrolysed to ADP+Pi which helps in formation of actin and myosin cross bridge during contraction.