In female mice that run with added weight, giving rapamycin three times a week blocks a key muscle growth signal, but giving it just once a week doesn’t keep that block going — so how often you dose...

In female mice that exercised with weighted wheels for 8 weeks, giving rapamycin three times a week blocked a key muscle signaling pathway, but giving it just once a week let the pathway bounce back a bit between doses — showing that how often you give the drug really changes how it works in muscles.

In female mice that exercised a lot for 8 weeks, taking rapamycin — a drug that affects aging — either once a week or three times a week didn’t stop them from getting stronger or improving their stamina.

Giving female mice a certain drug (rapamycin) once a week helps them run more on their own compared to giving it more often or not at all.

In female mice that run a lot, taking rapamycin frequently stops them from losing fat — even though exercise usually helps them slim down.

Even when mice are given a drug that blocks a key muscle growth pathway, running with added weight still makes their leg muscles bigger — showing that exercise can build muscle even when that pathway is turned down.