Grab the bar using a shoulder-width underhand grip. Slightly bend your knees and take a suspended position.
From the starting position pull your body up to the bar, contracting your back and arm muscles. Push your shoulder blades together. Pull yourself up until your face is in front of the bar at chin level. Exhale while pulling up and inhale while returning to extended elbows. Do the required number of repetitions.
Make sure you use the correct bar grip. Keep your body core firm while exercising. Return to the starting position using a slow, controlled motion and avoid sudden relaxation of your muscle tension.
The number of repetitions depends on the type of your training. Most training plans require maximum repetitions for this exercise. When you have done 10 in a series, you can add weight to your dip belt.
The term chin-up usually refers to movement when the athlete uses underhand grip (the palms facing the trainee – as opposed to pull-ups where overhand grip is used).
This exercise involves a large number of muscles including the lats (latissimus dorsi), biceps, brachialis, brachioradialis, teres major, deltoid (posterior part), teres minor, infraspinatus, levator, rhomboids, trapezius and even pectoralis muscles.
The main targets are lats. Biceps is very significantly involved (more than on pull-ups) and chin-ups can be successfully chosen as the main biceps exercise (for those who combine lats and biceps in one workout).
If possible, use a grip where the palms are either facing each other or they are positioned in a 45-degree angle towards each other. This is a more natural wrist position and it causes less wrist problems.
The torso should lean backwards in an angle of about 30 degrees. At the end of the contraction you should squeeze the shoulder blades together (scapular retraction).
If you gained enough strength you may consider using a belt with chain that enables addition of weighted plates (dip belt).
If you are not strong enough for this exercise you will probably choose to work with lat machine.