Lifting lighter weights many times in a row helps untrained young men build more muscle endurance than lifting heavier weights fewer times. After 8 weeks, they can do more reps before getting tired.

Lifting weights many times in a row (20-28 reps) helps young men who don't exercise get better at cardio, making them able to breathe easier and last longer during workouts compared to lifting fewer reps.

Lifting heavy weights for just a few reps makes untrained young men much stronger than doing more reps with lighter weights, especially after 8 weeks of training.

Lifting weights with fewer reps (3-11) builds more muscle than doing lots of reps (20-28) in young guys new to training, especially after 8 weeks.

Lifting lighter weights many times in a row helps well-trained young men do more push-ups longer than lifting heavier weights fewer times, after 8 weeks of training.

When you lift weights, doing a few heavy reps makes you stronger, doing lots of light reps helps your stamina, and doing a medium amount builds bigger muscles.