Final answer:
It is false that resistance exercises only involve the intended muscle; secondary and stabilizing muscles also contribute. Muscles work in pairs and provide support for resistance movements, which can lead to muscular hypertrophy involving multiple muscle groups.
Step-by-step explanation:
The statement that an individual is using only the muscle he or she intends to work on during resistance exercise is false. When performing a resistance exercise, both the targeted muscle and its supportive muscle groups are typically engaged. For example, during a bicep curl, the primary muscle worked is the bicep, a flexor muscle that closes the limb. However, secondary muscles such as the brachialis and brachioradialis in the arm, as well as stabilizing muscles in the shoulder and back, may also be activated to support the movement and maintain proper form.
Muscles work in pairs; for instance, while the biceps contract, the triceps serve as extensors to open the limb. This complementary action ensures a balanced movement and provides stability. Furthermore, the use of other muscle groups helps with the mechanical advantage when lifting weights.
Moreover, resistance exercises lead to adaptations such as the increase of myofibrils and muscle fibre thickness, resulting in muscular hypertrophy. This process often involves not just the isolated muscle but surrounding tissues as well.