Effect of protein supplementation on resistance training-induced gains in muscle

This is kind of meaningless as a summary metric, even if it is easier to compute. The overwhelming majority of readers, I assume, would prefer to know the relative improvement. An extra kilogram on a heavy lift, like a squat, is less meaningful than an extra kilogram on a lightweight lift, like a lateral raise.

The authors then go on to divide the total improvement per participant by the number of exercises to arrive at an average gain of 2.5kg per test of strength. Again, it's hard to know how interesting those strength tests are without reading the underlying literature. All I think the authors mention in the section on data extraction is that 1RM was extracted from "any 1RM strength test," so I assume they could be absolutely anything from a weighted pullup to stretching a therapeutic resistance band.

The authors conclude:

  > Though protein supplementation may slightly augment changes in 1RM (~9%),
  > which may be important for those competing in powerlifting or weightlifting,
  > it is pragmatic to advocate that if an increase in 1RM is the objective of
  > an RET programme, a sufficient amount of work and practice at or around the
  > 1RM is far more influential than protein supplementation.

> Dietary protein supplementation significantly enhanced changes in muscle strength and size during prolonged RET [resistance exercise training] in healthy adults. Increasing age reduces and training experience increases the efficacy of protein supplementation during RET.

> With protein supplementation, protein intakes at amounts greater than ~1.6 g/kg/day do not further contribute RET-induced gains in FFM [fat-free mass].