In all row variations, the should be the primary muscle group activated to complete the lift, while the work as a secondary muscle to help complete the exercise. biceps, triceps triceps, back back, biceps back, chest

The answer is "Biceps" and "Triceps"

Explanation:

A muscle contracts when the muscle filaments make strain against an outer opposition. Your biceps muscle contracts both concentrically and whimsically during the biceps twist. At the point when you twist the weight up, the biceps muscle makes enough power to defeat the outside obstruction.

During this period of concentric withdrawal, the muscle filaments abbreviate, pulling at the elbow joint and lifting your lower arm. At the point when you bring down the weight, the muscle strands don't make enough power to beat the outer obstruction. The strands stretch during this whimsical stage to control the drop of the weight.