For people who exercise casually but aren’t trained, doing light weightlifting with blood flow restriction helps grow fast-twitch muscle fibers almost as much as lifting heavy weights — and after 6 weeks, the difference between the two isn’t big enough to matter.

For people new to strength training, lifting light weights with restricted blood flow works just as well as lifting heavy weights for building muscle size over 6 weeks.

When adults do light weight training with restricted blood flow, their slow-twitch muscles grow as much or more than their fast-twitch muscles, which is different from heavy weight training where fast-twitch muscles usually grow more.

Doing heavy weights followed by light weights with restricted blood flow might help power athletes build more muscle by keeping muscle growth signals turned on longer.

Doing light weight training with blood flow restriction doesn't change the space around muscle fibers any more than heavy weight training in regular active people — after six weeks, both seem to have the same effect.

People who had never lifted weights before were split into two groups: one group lifted heavy weights normally, and the other lifted heavy weights while wearing bands that restricted blood flow. After 10 weeks, both groups got about the same amount stronger and their muscles grew about the same size — the difference wasn’t big enough to say one method was better than the other.