Weekly Infographics #14: Free Weights vs Machines & 8 Reps vs 25 Reps

A newsletter dedicated to summarizing interesting strength/hypertrophy related research.

1) Free Weights vs Machines for Hypertrophy

This study by Schwanbeck et al. established that a machine only program produced similar hypertrophy to a free weight only program.

These findings make sense.

Currently, mechanical tension is the best categorized stimulus for hypertrophy. Mechanical tension is equal to the force generated by muscle fibers (mechanosensors within the fibers detect force and transduce it into a signaling cascade that produces growth of the muscle fiber).

Following from this, to maximize overall muscle growth, in an exercise, we would want to recruit as many muscle fibers as possible and have each of them sustain at least decent degrees of their respective force capacities for a fair duration.

Ultimately, regardless of what modality you use (free weights, machines, or even bodyweight), so long as you near failure within the 5–35 rep range, you likely achieve sufficient overall mechanical tension levels for the involved muscles.

2) 8–12 Reps vs 25–35 Reps for Hypertrophy

When it comes to building muscle, provided repetitions are performed near enough to failure, a wide range of repetition numbers are similarly effective.

This particular study by Schoenfeld et al. established in trained men, hypertrophy outcomes were similar when training with 8–12 or 25–35 repetitions.