For young male rugby players who lift weights, doing more reps to build muscle might slightly hurt their jumping ability compared to training for pure strength — but the measurement wasn't perfect, so we're not totally sure.

Young male rugby players who do high-volume muscle-building workouts might see a small drop in their jump performance compared to those doing heavy strength training — but the results aren't super clear because different equipment was used.

In young male rugby players who lift weights, doing high-rep, lighter weight workouts leads to worse sprinting and agility performance for up to two days compared to low-rep, heavy weight workouts.

For young male rugby players who lift weights, doing high-rep, lighter weight workouts seems to slow them down and make them less agile for a day or two more than doing low-rep, heavy weight workouts.

Even though the players got stronger, their ability to jump higher or more powerfully didn’t improve after five weeks of leg press training — meaning strength on the machine doesn’t automatically make you jump better.

Doing drop sets (lifting heavy, then lighter weights without resting) builds muscle just as well as doing regular sets with longer breaks, at least in young, experienced lifters.