ACE Personal Trainer Practice Exam

When a muscle acts eccentrically, it is experiencing resistive force. In an eccentric contraction, the muscle lengthens while generating tension, typically against an external load, such as gravity or resistance. This type of contraction occurs when a muscle is acting to control the lowering of a weight or to slow down a movement, meaning that the force produced by the muscle is less than the external force acting on it.

The resistive force in this context refers to the opposing force that the muscle must work against. For example, when performing a bicep curl, as the weight is lowered back down, the bicep muscle elongates while still generating tension to control the descent of the weight, hence experiencing resistive force.

Understanding this concept is crucial for personal trainers as it influences how they design programs for strength training, injury prevention, and rehabilitation. Recognizing when and how muscles are acting eccentrically allows trainers to tailor exercises that effectively utilize this type of muscle action for various fitness and rehabilitation goals.