Working to build some wings wide enough to glide with or guns you can wear out of your tank top for the beach? Picking the right exercise might be hindering your results. Let it be known, the chin up and pull up are NOT the same and the muscle groups that they work differ greatly based on the variation and exercise that you choose.
Like with any other exercise, the first step is understanding what part of the body it actually works. Then you must understand how that muscle functions within the body and then that will give you the understanding to perform an exercise with good form. Let’s start with a minor lesson on anatomy and biomechanics because after all, you can’t physically build a house without drawing the blueprints first.
Muscles Involved in Both Movements
Latissimus Dorsi: The Lats! The wings! The clay that creates that desired v-taper look. The lats function is to support different movements of the shoulder and are engaged when the humerus (elbow) moves towards the trunk or abdomen.
Biceps: The mountain peaks! The guns! The biceps function in assisting the movement of the shoulder and the forearm, but in this case act more notably to lift the forearm upwards.
Posterior Deltoid: Truly an underappreciated muscle by many but a key component of achieving full 3D boulder shoulders. The posterior deltoids assist in maintaining proper posture by keeping the shoulders rotated to the back. As you can imagine, in any pulling movement the posterior deltoids must be actively engaged to perform the movement with proper posture.
Trapezius: Most people don’t realize this but the Traps are actually a back muscle. Yes, the traps attach to your neck but they extend halfway down your back. The Traps function to move and stabilize the neck in various directions, as well as to move the shoulder blades to desired locations. In other words, an important muscle in maintaining posture.
Rhomboideus: The Rhoms! A pair of diamond shaped muscle fibers located in between your scapula. Their main function is to adduct and elevate the scapula (English: squeeze the shoulder blades together and upwards).
The Differences Between The Pull Up & Chin Up
Okay, now that we understand the major muscle groups involved in both exercises we can start talking about the major differences between them.
The Pull Up (traditional)
There are many variations of the pull up both in terms of grip and range of motion. But for the sake of this article I will just discuss the traditional version.
Traditionally the pull up is performed with a pronated grip (palms facing away from the athlete). The hand grip is shoulder width apart and the objective is to maintain a proper back posture (shoulders back with a slight arch in the back) while shortening the distance between the forearm and the bicep. The best way to ensure a good contraction through your back is to actually keep your eyes up on 45 degrees towards the ceiling.
As I mentioned previously there are many variations of this movement; wide grip pullups being one of them. Wide grip pullups are a great way to put extra focus on the lats. Whenever trying to put more emphasis on the back it is extremely important to keep your eyes up and your shoulders back. Another pro tip for you is to imagine your hands as hooks. What I actually like to do is keep my thumbs on the outside of the bar and release my grip a little bit. With this kind of grip, you release the tension off the forearm. This tends to relax the bicep and allows you to pull more with your back.
Primary movers: Latissimus Dorsi, Rombhoids, Traps
Secondary movers: Biceps, Posterior Deltoid
The Chin Up
Traditionally, the “Chin-up” was a simple reference to the range of motion where the person performing the exercise had to get their chin above the bar. However, over the years the goal of achieving a chin up became a raise of raising chins rather than working muscles.
Thus, we adopted the easiest way to do so in a comfortable fashion. Similar to a kipping crossfit pullup. The goal is to get up to the top, so you kip. The chin up is simpler to accomplish with a supinated grip (palms towards the person exercising) and having the hand placement slightly closer than shoulder with.
The supinated grip provides a clear, easy pathway for the bicep to come in and help out with the motion. After the bicep engages slightly, the shoulder is stabilized into a proper postural position (hopefully) which then allows for the back to engage and help with the movement.
As with the traditional pullup, there are many variations of the “Chin up” which may include a wider grip or a more arched back; allowing the person to exercise more lat utility. But the variation I am covering here is a neutral hanging position with a supinated grip.
Primary movers: Biceps, Posterior Deltoid, Latissimus Dorsi
Secondary movers: Rhomboideus, Trapezius
The key to note here is that there are variations for both exercises which will put more emphasis on different muscle groups but if the key goal is to put more emphasis or focus on your back, a pronated pull up will be the better choice.
If your goal is build bigger biceps, then a supinated chin up is a fantastic compound movement that you can add to your bicep routine.