Question

which of the following statements is true?multiple choicephosphocreatine provides about 85% of the energy needed to fuel muscles during endurance physical activities.amino acids are a major source of energy for contracting muscles.during high-intensity exercise, the rate of glucose oxidation increases.glucose is the primary fuel for resting muscles.

Answer 1

The true statement regarding muscle energy systems is that during high-intensity exercise, the rate of glucose oxidation increases. Creatine phosphate rapidly provides energy but only for about 15 seconds. Glycolysis and aerobic metabolism are more important for longer-duration activities.

Step-by-step explanation:

A student inquired about the energy systems used during physical activity. The correct statement regarding energy provision for muscle activity is: During high-intensity exercise, the rate of glucose oxidation increases.

Creatine phosphate is indeed used as a fast energy source but can only supply energy for a maximum of about 15 seconds during intense muscular effort. Glucose is a primary source of fuel and becomes increasingly important as glycolysis kicks in once creatine phosphate stores are depleted. Amino acids are not a major energy source for muscle contraction and phosphocreatine is not the primary source of energy for endurance activities, as it is quickly used up. For resting muscles, aerobic respiration is the key, mainly using glucose for ATP production.