Training by app works, but the gains landed in the legs, not the arms
Across 32 randomised trials, resistance training prescribed through apps and websites produced a small but real improvement in neuromuscular fitness compared with no intervention or usual care. Lower body measures improved moderately; upper body measures did not shift significantly.
For you: If an app is the only way you will do resistance work, this suggests it beats doing nothing, though the measured gains were small and leg-heavy.
What it shows: Real but modest: pooled results from 32 trials show phone and web programmes do build measurable fitness, though the overall gain was small and showed up in the legs rather than the arms. Most trials studied patient groups rather than everyday gym-goers, and how the exercise was actually prescribed was often poorly reported.Meta-analysis · Int J Behav Nutr Phys Act