Which of the following phrases best fits the term concentric phase of an isotonic muscle contraction?

The term "concentric phase" refers to the part of an isotonic muscle contraction where the muscle shortens while generating force. This phase typically occurs when lifting a weight or overcoming resistance.

Choosing a muscle contraction performed with controlled speed accurately reflects the nature of the concentric phase. During this phase, the muscle fibers contract in a smooth and deliberate manner to effectively manage the force being exerted. This control is essential not just for maximizing strength and performance but also for ensuring safety and reducing the risk of injury.

The other options do not align with the definition of the concentric phase. A quick contraction to achieve higher reps suggests a focus on speed rather than the control that is fundamental during this phase. An uncontrolled contraction with minimal weights denotes a lack of control, which contradicts the purposeful intent behind a concentric contraction. Lastly, a contraction lasting more than 10 seconds refers to a static or isometric phase rather than the dynamic, intermittent action characteristic of the concentric phase.