AFAA Personal Trainer Certification 2025 – 400 Free Practice Questions to Pass the Exam

During concentric training, the muscle shortens while exerting more force. This occurs when a muscle contracts and generates enough force to overcome the resistance being applied, leading to movement. For instance, when performing a bicep curl, as the bicep muscle contracts to lift the weight, it shortens in length while still producing a significant force greater than the weight being lifted.

This phase of muscle contraction is crucial in building strength and power, as it involves the active engagement of muscle fibers to create movement against an external load. In concentric training, the ability of the muscle to shorten effectively is essential for performing exercises that require lifting or moving weights, contributing to muscle hypertrophy and strength gains over time.

Other options do not accurately describe the concentric phase: in cases where the muscle exerts less force than the resistance, it would not be considered concentric; if the force exerted is equal to the resistance, the muscle is in an isometric contraction, and if it lengthens under tension, that describes eccentric training.