Energy Systems & Exercise Physiology Flashcards

Which of the following correctly identifies the three primary energy systems used during exercise?

Answer: Phosphagen, Glycolytic, and Oxidative

The three primary energy systems are the phosphagen (ATP-PCr), glycolytic (lactic acid), and oxidative (aerobic) systems, each dominating at different exercise intensities and durations.

Which energy system provides ATP most rapidly but is limited to only 8–10 seconds of maximal effort?

Answer: Phosphagen (ATP-PCr) system

The phosphagen system uses stored ATP and phosphocreatine to generate energy almost instantaneously but is depleted within 8–10 seconds of all-out effort.

At low-to-moderate exercise intensities, the aerobic energy system primarily relies on which substrate?

Answer: Fat (free fatty acids)

At low-to-moderate intensities, fat (free fatty acids) is the predominant fuel for the aerobic energy system due to its high energy yield per gram.

VO2 max is best defined as the:

Answer: Maximum rate of oxygen consumption during intense exercise

VO2 max is the maximal rate at which the body can consume and utilize oxygen during intense exercise, and is the gold standard measure of aerobic capacity.

The lactate threshold is best described as the exercise intensity at which:

Answer: Blood lactate concentration rises faster than it can be cleared

The lactate threshold is the point where lactate production exceeds the body's clearance capacity, causing blood lactate to accumulate and signaling a shift toward anaerobic metabolism.

During a 10-second all-out sprint on an indoor cycling bike, which energy system contributes the most ATP?

Answer: Phosphagen (ATP-PCr) system

A 10-second maximal sprint is powered almost entirely by the phosphagen system, which uses stored ATP and phosphocreatine in the muscle.

Cardiac output during exercise is calculated as:

Answer: Heart rate × stroke volume

Cardiac output equals heart rate multiplied by stroke volume, representing the total volume of blood the heart pumps per minute.