Doing more sets of squats and leg exercises makes people feel like they worked harder, even if their muscles don’t get more swollen or weaker.

When guys who regularly lift weights do more sets of squats and leg exercises in one workout, they feel like they worked harder afterward.

When you do more sets, you feel it way more than your muscles or strength show it — your brain notices the effort before your body shows physical signs.

People feel like they’re working much harder during a 30-minute hydraulic machine HIIT workout than during weightlifting, running, or biking, even though they’re resting part of the time.

After doing a lot of leg exercises in one workout, guys who are used to lifting feel less recovered the next day or two than after doing fewer sets.

If you lift weights until you can't do another rep, your body feels like you worked harder than if you stopped before failure—even if you did the same total number of reps and sets.