>Content
>1. Biomechanics
>2. Pullup vs Chinup vs Hammer Pullup
>3. Closegrip vs Widegrip
>1. Biomechanics
Main movements: Shoulder Extension, Shoulder Adduction, Elbow Flexion, Scapular Downward Rotation, Scapular Depression, Scapular Adduction
Main movers: Lats, Teres Major, Biceps, Brachioradialis, Posterior Delts, Traps, Rhomboids
Secondary movers: Sternocostal Pec Major, Levator Scapulae & Pec Minor, Triceps (long head), Rotator Cuff, Brachialis
Primary Grip: Flexor Digitorums, Flexor Pollicis, Adductor Pollicis, Opponens Pollicis
>Lats
The largest, strongest, and most important muscle for the pullup/chinup.
The Latissimus Dorsi are involved in all of the movements - shoulder extension (pulls the humerus down, bringing the elbow close to the body in the sagittal plane of motion), shoulder adduction (bringing the humerus close to the body in the frontal plane of motion), elbow flexion (through the passive tendon action of the biceps, more info below), and the scapular part of the movement (depression, adduction, and downward rotation).
>Teres Major
Helps perform shoulder extension and adduction. Both the Teres Major and the Latissimus Dorsi have virtually the same strength of pull for both extension and adduction, regardless of whether the bar is closer to the coronal or frontal plane.
>Posterior Delts
Helps perform shoulder extension, but is weaker for shoulder adduction. This means that closer grip widths are better for the posterior delts than wider grip widths (more on this later).