hypertrophic

This term carries a clinical, sterile tone and is almost exclusively found in medical or athletic contexts. It describes a physical expansion that is structural rather than numerical, meaning the existing cells grow larger rather than new cells being created. In a fitness context, the word is often stripped of its pathological connotation to describe the intentional growth of skeletal muscle. While a doctor might use it to describe a dangerous thickening of the heart wall, a bodybuilder uses it to describe the desired result of a specific training regime.