NSCF Personal Trainer Complete Practice Exam

Ankle dorsiflexion is primarily caused by concentric contraction of the anterior tibialis muscle. During dorsiflexion, the anterior tibialis actively contracts to pull the foot upwards toward the shin, which is what allows the toes to point upward and reduces the angle between the dorsum of the foot and the leg.

Concentric contractions involve the muscle shortening while generating force. In the context of the anterior tibialis, this means that as the muscle contracts, it pulls the foot into the dorsiflexed position. This movement is essential for activities such as walking, running, and climbing stairs, where the foot needs to clear the ground and properly position itself for the next step.

In contrast, eccentric contraction occurs when a muscle lengthens while under tension, which is not related to the active lifting of the foot. Isometric contraction refers to maintaining muscle tension without changing the length, providing stability, rather than facilitating movement. Passive stretching involves a muscle being elongated without active contraction. Therefore, the concentric contraction of the anterior tibialis is the correct choice in this context, as it directly contributes to the active movement necessary for ankle dorsiflexion.