If young women do bicep curls on an incline bench, they’ll likely grow the upper part of their biceps more, but if they use a preacher curl bench, they’ll grow the lower part more — the way you curl...

If young women do incline bicep curls twice a week for 8 weeks, their upper arm muscles grow more than if they did preacher curls — showing that the type of curl might change where the muscle grows most.

For women who work out regularly, doing preacher curls or incline bicep curls doesn't seem to change where their biceps grow — both exercises lead to similar growth patterns after 9 weeks.

If young women do incline bicep curls twice a week for 8 weeks, their upper arm muscles grow more than if they did preacher curls — the type of curl really affects where the muscle grows.

For beginners, lifting weights with one arm or both arms at the same time results in similar biceps growth, indicating that the total amount of weight lifted and number of repetitions matter more than whether one or two arms are used.

In untrained young women, doing biceps curls with one arm or both arms at the same time leads to similar increases in biceps muscle thickness after 8 weeks, indicating that the total amount of work and load applied matters more than whether the exercise is done one arm at a time or both together.