Izomtömeg

Izomtömeg, in English skeletal muscle mass, refers to the total mass of skeletal muscle tissue in the body. It is a major component of lean body mass and varies with sex, age, fitness level and genetics. Skeletal muscle is the tissue primarily responsible for voluntary movement, posture, and force production.

Muscle mass increases largely through hypertrophy in response to resistance training, especially with progressive overload. Adequate protein intake, energy availability and rest support gains. Hormonal factors (testosterone, growth hormone, insulin-like growth factor), neuromuscular adaptations, and fiber composition also influence izomtömeg. Distribution differs by limb and region; legs and back muscles typically account for large portions of total mass.

Measurement methods include dual-energy X-ray absorptiometry (DEXA), magnetic resonance imaging (MRI) or computed tomography (CT), and bioelectrical impedance analysis (BIA). Each method has limitations in accuracy and body composition context.

Muscle mass typically increases in young adulthood and declines with age, a process called sarcopenia. Inactivity, malnutrition, certain diseases or medications can accelerate loss. Preserving or increasing izomtömeg is associated with better metabolic health, functional ability, and resilience to illness.

Strategies to increase muscle mass focus on progressive resistance training, adequate protein intake (commonly about 1.6–2.2 g/kg/day for those seeking gains), and a modest caloric surplus. Training should target all major muscle groups, with sufficient volume and recovery. Attaining sustainable gains requires consistency over months and years.