Final answer:
True, isotonic contractions are often preceded by isometric contractions as the muscle initially engages to overcome a load's resistance before movement occurs.
Step-by-step explanation:
Isotonic muscle contractions, where the tension in the muscle stays constant, involve a change in muscle length to move a load. This includes both concentric contractions, where the muscle shortens, and eccentric contractions, where the muscle lengthens. Isometric muscle contractions, on the other hand, involve increasing muscle tension without a change in muscle length, because the muscle cannot overcome the load. In many physical activities, an isometric contraction often precedes an isotonic contraction. For example, one might engage in an isometric contraction when initially attempting to lift a heavy weight off the ground, creating tension in the muscles without movement, followed by an isotonic contraction once the movement begins.