Biomechanical Principles

Correct answer: A. Training and performance

The use of science improves both training and performance in physical education. Scientific principles help teachers and coaches plan workloads, measure fitness, analyse movement, prevent injuries and select suitable recovery methods. These improvements can make practice safer and more effective, so option A is correct. The other options are either unrelated to scientific training or far too narrow to represent its effect.

Correct answer: D. Safe adaptation ability of the body

The governing training concept is progressive overload with safe adaptation. When exercise load rises gradually, the muscles, cardiovascular system, coordination, and recovery processes receive time to adjust and become stronger. A sudden heavy load can cause excessive fatigue or injury, and avoiding practice cannot produce adaptation. Consequently, option D is correct because it states the physiological basis of gradual progression.

Correct answer: A. Reducing risk and ensuring safe participation

The governing principle is risk management in physical activity. Safety rules convert this principle into action by requiring suitable equipment, proper technique, warm-up, supervision, and clear procedures for emergencies. Thus option A is correct because it reduces avoidable danger while preserving participation. Options B and C deliberately increase harm, whereas D wrongly suggests that safety eliminates the need for practice.