Resistance training induced changes in integrated myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle damage
Skeletal muscle hypertrophy is one of the main outcomes from resistance training (RT) but how it is modulated throughout training is still unknown. We show that changes in myofibrillar protein synthesis (MyoPS) after an initial resistance exercise (RE) bout in the first week of RT (T1) were greater than those seen post RE at the third (T2) and tenth week (T3) of RT, with values being similar at T2 and T3. Muscle damage (Z band streaming) was the highest during post RE recovery at T1, lower at T2 and minimal at T3. When muscle damage was the highest, so was the integrated MyoPS (at T1) but neither were related to hypertrophy; however, integrated MyoPS at T2 and T3 were correlated with hypertrophy. We conclude that muscle hypertrophy is the result of accumulated intermittent increases in MyoPS mainly after a progressive attenuation of muscle damage.
The Journal of physiology