Training muscles in isolation builds size but not 'usable' strength; real functional strength comes from training the body as a coordinated system (Functional Patterns method).

noli's read

Training specificity is a real, documented phenomenon: a 2025 meta-analysis (Saeterbakken, Stien, Paulsen et al., Sports Medicine, 43 studies, 1,660 participants) found moderate-to-large transfer to the trained task (d=0.98) but only small-to-moderate transfer to an untrained isometric task (d=0.42); a 2024 study (Frontiers in Aging) in older adults found traditional training (free weights/machines) produced large strength gains on the trained lifts but limited carryover to gait speed, while functional training with a weighted vest transferred better to functional tests with more modest strength gains — so specificity cuts both ways. But the conclusion that 'isolation doesn't build usable strength' goes too far: a meta-analysis on the generality of strength adaptation found a significant, moderate effect (d=0.8) on UNTRAINED movements, and a 2024 meta-analysis in older adults shows machine-only training (about as 'isolated' as it gets) significantly improves functional tests (sit-to-stand, timed-up-and-go), concluding that 'training a movement rather than a muscle might be unnecessary.' Specificity is real but partial; general strength transfers considerably more than this post suggests. Verdict: mixed.

the sources

No named source held this one up — that absence is part of the verdict.