If you do the same amount of work with your arm in front or behind you, you'll get just as strong at lifting heavy weights — the position doesn't matter.

If you use the same weight and do the same number of reps, it doesn't matter if you curl with your arm in front or behind you — what matters is just doing it consistently and getting stronger over time.

When people who regularly lift weights perform exercises that stretch their muscles fully, they gain more strength in movements that involve those stretched positions, such as bending the elbow while the muscle is lengthened.

If young men who haven't exercised before do either multi-joint exercises (like pull-ups) or single-joint exercises (like bicep curls) for 10 weeks, their arm strength increases by about the same amount - neither type of exercise is clearly better than the other.

In untrained young women, lifting weights through the first half of the elbow movement for eight weeks leads to greater gains in overall strength than lifting through the second half, even if the second half involves heavier weights.

In untrained young women, performing bicep exercises using only the first half of the movement range for eight weeks leads to more muscle growth in the lower part of the biceps and greater strength gains than using only the second half of the range.