IB Sports, exercise and health science A.2.3 Energy Systems Questionbank

(a) Using the figure, identify the approximate running speed at which the lactate inflection point occurs.

(b) Describe how blood lactate concentration changes before and after the lactate inflection point.

(c) Explain why exercise intensity above the lactate inflection point cannot usually be sustained for prolonged periods.

(d) Discuss why the lactate inflection point may be a better predictor of endurance performance than VO₂ max alone.

A coach compared the estimated energy system contribution during four training sessions performed by the same athlete.

Table: Estimated contribution (%) of the three energy systems during different training sessions

(a) Using the table, identify the training session with the greatest oxidative contribution.

(b) Describe the relationship between exercise duration and oxidative system contribution shown in the table.

(c) A basketball player performs repeated maximal jumps throughout a game. Using the table, explain why the ATP–PC system is important during these movements.

(d) Using the table, evaluate why repeated 200 m sprints rely on contributions from all three energy systems.

A sports scientist assessed the maximal oxygen consumption (VO₂ max) and 5 km running performance of four recreational runners.

Table: VO₂ max and 5 km performance

(a) Using the table , describe the relationship between VO₂ max and 5 km performance.

(b) State which runner demonstrates the greatest running economy.

(c) Explain how running economy influences endurance performance independently of VO₂ max.

(d) Apart from training status, discuss two factors that may influence an individual's VO₂ max.

Researchers analyzed the relative contribution of the three energy systems, phosphagen (ATP-PCr), anaerobic glycolytic, and oxidative, across five Olympic sports. The activities varied in intensity and duration, providing insight into energy system usage along the energy continuum. The data in the table summarizes the estimated percentage contribution of each energy system for each sport based on simulated competition conditions.

(a) Using the table, identify the sport with the highest contribution from oxidative metabolism

(b) Describe the trend in ATP-PCr and oxidative contributions between boxing, judo, and wrestling.

(c) Wrestling shows the highest glycolytic contribution of the five sports. State one advantage and one limitation of high reliance on the glycolytic system during performance.

(d) Despite being explosive and intermittent, karate and judo show over 40% oxidative contribution. Explain two physiological reasons why oxidative metabolism plays a significant role in these sports.

Transition from fat to carbohydrate metabolism

Point of peak aerobic efficiency

Onset of greater reliance on anaerobic glycolysis

Crossing the lactate threshold due to anaerobic glycolysis