Oefening en spierprestaties

Physical training has two broad types—muscle-strengthening endurance exercises and muscle-enlarging resistance exercises.

Endurance exercises such as running, swimming, or cycling use slow muscle fibers for low-force and repetitive movements.

After exhausting the sarcoplasmic reserves of carbohydrates, lipids, and proteins for aerobic respiration, the slow fibers start drawing nutrients from the circulating blood to support contractions.

Regular endurance training stimulates extensive angiogenesis that increases oxygen supply to the muscle fibers, gradually building stamina and allowing extended activity without fatigue.

In contrast, resistance exercises such as weightlifting, sprinting, or jumping require more strength than stamina and utilize fast fibers.

The initial contractions of fast fibers rely on ATP and creatine phosphate reserves, moving on to the anaerobic breakdown of glycogen for these power-intensive muscle contractions.

Consistent resistance training helps to change muscle size by enlargement of cells. It also builds strength by converting the fast oxidative muscle fibers to the fast glycolytic type.

Additionally, tendons undergo strengthening to support muscles while contracting against high-resistance forces, further adding to overall muscle mass.