Mazzetti et al., 2000 — Medicine & Science in Sports & Exercise
n = 20 moderately trained men, 12-week resistance-training protocol
Finding: Directly supervised resistance training produced significantly greater increases in maximal squat and bench press strength than the same program performed unsupervised. Same exercises, same weeks — the difference was a coach watching and adjusting.
Why it matters for LIM: Most people can't afford a coach in the room every session. LIM's thesis: an AI coach that reviews every logged session and adjusts the next one recovers a meaningful share of that supervision effect at app pricing.