International Sports Sciences Association (ISSA) Trainer Practice Exam

Which statement is true regarding concentric contractions?

1. Muscles lengthen to produce movements

2. Muscles remain stationary

3. Muscles shorten to produce movements

4. Muscles engage only during eccentric phases

The correct answer is: Muscles shorten to produce movements

Concentric contractions are characterized by the shortening of muscles to produce movement. This physiological process occurs when a muscle generates enough force to overcome an external resistance, allowing for movement against that load. For instance, during a bicep curl, as the weight is lifted, the bicep muscle shortens, effectively pulling the forearm upward. This type of contraction is crucial for activities that involve lifting or moving against resistance, highlighting the importance of concentric contractions in strength training and various sports. In this context, the other options do not accurately describe concentric contractions. Lengthening muscles to produce movements would pertain to eccentric contractions, where the muscle elongates while still under tension. Remaining stationary does not illustrate the physiological changes occurring during muscle contractions and typically refers to isometric contractions. Finally, stating that muscles engage only during eccentric phases is misleading, as they also actively engage during concentric phases for effective movement execution.