What is the Origin of Lean Mass Accretion Rate?

This term originates from sports physiology and body composition analysis, where tracking muscle gain is paramount for performance and health outcomes. 'Accretion' implies a gradual accumulation, emphasizing a slow, steady biological process rather than rapid, unsustainable changes.

What is the Mechanism of Lean Mass Accretion Rate?

The rate is dictated by the net balance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB), a concept known as net protein balance. High rates are achieved when anabolic signaling pathways, driven by hormones like IGF-1 and sufficient amino acid availability, maximally drive MPS while mitigating catabolic signals like high cortisol. Training stimulus provides the necessary trigger for this process to occur efficiently.

Lean Mass Accretion Rate

Meaning

The quantifiable velocity at which non-fat body mass, primarily skeletal muscle and bone mineral density, increases over a specified period, usually expressed in kilograms or pounds per week or month. This metric is a primary indicator of successful anabolic signaling and effective utilization of nutrients for tissue synthesis. A healthy rate signifies positive adaptation to physiological stressors.