The Horizontal Bars are closely associated with chin-ups, one of the most basic pulling exercises Chin-ups are one of the best tests of a person's strength to weight ratio a primary indicator of upper body strength.
1) Can be used for variety of pull-ups, and stretching.
2) Target Muscles: Biceps, lower abs, forearms, lats
Secondary Muscles: Mid. & upper abs, mid. Back
3) To perform a pull-up or chin-up, hold onto the bar, use the arms to pull up until the chin is level with or above the bar. Lower again and repeat according to your capability. Pull-ups / Chin-ups can be done with two hand grips, forward or reverse, each strengthening different muscles.
4) The forward bar grip (backs of hands facing you) places more emphasis on the trapezius and muscles of the back, whereas the reverse bar grip (or underhand grip) is narrower and places focus on the biceps
If You have medical condition which might need special attention then seek medical or experts advice. Protection from adult is required when children and elder are using it.