If you're a guy who's already used to lifting weights, doing fewer reps with heavier weights and longer rests might boost your bench press more than doing lots of reps with lighter weights and short breaks — at least over 8 weeks.

Lifting heavy weights with fewer reps and longer breaks makes your arms stronger and bigger faster than doing more reps with lighter weights and shorter breaks, especially for guys who already work out.

If you're already strong and lift weights, training each muscle group either once or five times a week for eight weeks will give you about the same strength gains on the bench press, squat, and row.

If you're a guy who lifts weights regularly, eating 15% more calories than you burn might help you get stronger on the bench press compared to eating just a little extra or staying even, but it won’t give you an extra boost on squats or leg muscle growth.

If you're a guy who's already been lifting weights, doing fewer reps with heavier weights and longer rests might build more arm muscle over 8 weeks than doing more reps with lighter weights and shorter breaks.

If you're already strong and lift weights regularly, doing 10–15 hard sets per muscle group each week for 2 months will make you stronger and add a little muscle — whether you train your whole body every day or just once a week.