What type of exercise is crucial for building muscular capacity?

Resistance training is crucial for building muscular capacity because it involves exercising muscles against a resistance, which leads to adaptations such as increased muscle strength, size, and endurance. This type of training stimulates muscle fibers and encourages growth through the process of mechanical tension and muscle damage, prompting the body to repair and strengthen the muscles involved.

In contrast, aerobic exercise primarily focuses on enhancing cardiovascular endurance and does not adequately target muscle hypertrophy or strength development. Flexibility exercises promote the range of motion in joints but do not significantly contribute to building muscular capacity. The term 'qualitative exercise' is less commonly defined in the context of fitness and does not specifically refer to the systematic strengthening of muscles, making resistance training the most relevant and effective choice for developing muscular capacity.