Use an ab wheel or a barbell with plates on it and on your knees, arms locked out roll out the ab wheel or barbell as far as you can and then pull it back to the start.
Keep your midline tight and don't let your back or hips break.
Six Week, 30-Session long training plan sport-specifically designed to train athletes for a rock climbing trip, or as focused, rock-gym based training cycle. This plan is focused on increasing the athlete's finger, grip and forearm strength, and also includes general work capacity, and core strength training.
The plan can be completed in any rock gym which includes a bouldering area, campus boards, and general fitness area, or a rock gym and a any commercial general training gym. CLICK HERE.