ACE Personal Trainer Practice Exam

What does the term 'Motive Force' refer to in muscle action?

1. The muscle lengthens while creating tension

2. The muscle shortens while creating tension

3. The muscle remains static

4. The muscle relaxes during tension

The correct answer is: The muscle shortens while creating tension

The term 'Motive Force' in muscle action refers to the ability of a muscle to generate tension in order to produce movement, specifically through shortening of the muscle fibers. When a muscle shortens while creating tension, it is performing a concentric contraction, which is a key mechanism through which muscles generate force to overcome resistance or to accelerate a body segment. This process is essential for tasks such as lifting weights or performing any physical activity that involves movement against an opposing force. In essence, the correct answer aligns with the physiological principle of concentric contractions, where the shortening of muscle fibers results in movement and lift. Understanding this concept is vital for personal trainers when designing effective exercise programs that utilize the body's natural mechanics for strength training and overall fitness.