b68a6d63_dyweight_Exercises___Fitstream__Notes
[Exercise] Chin-ups [Notes] 
Hand positioning is changed to an underhand variation which means that the biceps are worked harder than pull-ups. This exercise is slightly easier than standard pull-ups, which places greater emphasis on the back muscles.
Pull-up Exercise Guide, Progression Exercises, Hints and Tips - Bodyweight Exercises - Fitstream
Notes