Which factor does not dictate the contribution of energy systems being used during exercise?

The contribution of energy systems during exercise is primarily influenced by the duration, intensity, and type of activity being performed. Each of these factors plays a crucial role in determining which energy system is predominantly activated.

Duration of exercise is important because different energy systems are utilized over varying time frames. For instance, the phosphagen system operates for extremely short bursts of activity (up to about 10 seconds), while the aerobic system is engaged during prolonged efforts.

Intensity of exercise also dictates energy system utilization. Higher intensity activities may rely on anaerobic pathways, while lower intensity, longer-duration activities often utilize aerobic metabolism.

The type of activity performed ties closely to both duration and intensity, influencing which systems are activated. For example, sprinting versus long-distance running will activate different energy systems based on their unique demands.

Skill level, however, does not directly influence the biochemical mechanisms of energy production. It may affect how efficiently a person can perform an exercise or their ability to sustain effort, but it does not dictate which energy systems are at work during the activity. Therefore, this factor does not play a role in the physiological energy contributions themselves.