Horizontal Pull Up
An
excellent exercise for both back and forearm grip strength, however only suitable
for conditioned athletes. 
Make sure that the bar is strong and secure, and
that both your hands and bar are dry prior to performing this exercise, as
extreme care should be taken not to slip in the final phase.
Hold a solid pull-up bar, grasping the bar with both hands, in an underarm grasp, shoulder width apart, having your thumbs wrapped under the bar for a strong grip.
From
a straight-arm position, smoothly pull yourself up, however rather than taking
your chin over the bar, focus on lifting your lower chest to the bar, whilst
lifting your legs up straight, aiming to make your body horizontal to the
floor.
You
may find it difficult at first to perform with your body and legs straight,
so aim to commence the movement with your body at a 45 degree angle, however
still take your lower chest to the bar.