Final answer:
Resistance training mainly develops muscular strength and muscular endurance by utilizing fast-twitch muscle fibers, leading to increased muscle size and stronger connective tissues.
Step-by-step explanation:
Training against resistance primarily develops muscular strength and muscular endurance, which are key health-related components of fitness. Muscular strength is the ability of a muscle to exert force during a contraction, while muscular endurance is the ability of a muscle to continue contracting over a period without fatigue.
During resistance exercises, the body utilizes fast-twitch muscle fibers (FG fibers) to produce short, powerful movements. These exercises increase the formation of myofibrils within the muscle fibers, causing hypertrophy or an enlargement of the muscles involved. Unlike endurance exercises which may increase capillary density and mitochondria, resistance training primarily increases muscular size and strength along with the connective tissue development, enhancing the muscle's ability to handle stress. Flexibility is influenced by exercises that involve stretching, not by resistance training directly.
It's worth noting that genetic differences, such as the proportion of fast-twitch versus slow-twitch muscle fibers in an individual, can affect how much one benefits in terms of endurance from aerobic activity. Nonetheless, regular resistance training is an effective way to improve muscular fitness and contributes to overall health and well-being.