The chin-up (also known as a chin/chinup) is a strength training exercise. People frequently do this exercise with the intention of strengthening muscles such as the latissimus dorsi and biceps, which extend the shoulder and flex the elbow, respectively.
It is a form of pull-up in which the range of motion is established in relation to a person's chin.
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A chin up is named by bringing the chin up through space, specifically in relation to its position with the bar or other hand grips. This can be either touching the bar (more easily done by extending the neck, though that could be considered cheating) or by bringing the chin over the bar.
This is usually achieved most easily with vertical forearms that are close to the body. For most, bringing the chin this high is most easily achieved with a supinated (underhanded, palms-toward) grip. Due to this, the phrase "chin up" has become associated with pulling with this type of grip. Some have delegated the term pull-up to refer to the pronated (overhanded, palms-away) grip. In spite of this, many refer to pull-ups with a pronated grip also as chin-ups, and the supine grip is still regularly called a pull-up.
Some organizations such as the American Council on Exercise have adopted this new terminology, issuing statements such as: "a chin-up differs from a pull-up in that the puller's hands are facing towards him or her in a chin-up, and away in a pull-up."[1] Organizations such as the United States Marine Corps however, use the term pull-up interchangeably to refer to both the overhand and underhand grips.[2]
A chin-up has a variety of different forms.[3]
The movement begins with the arms extended above the head, gripping a hold. It may be fixed, such as a chin-up bar [4] or moving, such as gymnastic rings or rotating handles.
The body is pulled up, with the bar approaches or touches the upper chest. A chin-up is considered complete based on a variety of criteria in relation to where the chin should be in respect to the bar, or in respect to the hand grips.
The body is then lowered until the arms are straight, and the exercise is generally repeated.
Like any pull-up, chin-ups can be performed with a kip, where the legs and back impart momentum to aid the exercise, or from a dead hang, where the body is kept still. Performing the chin-up correctly can be tricky with a supinated grip, because of the natural tendency to do most of the work with the elbow flexors (largely biceps) rather than the shoulder extensors (largely lats).
Initiating the pulling action with scapular depression may help avoid this problem. The exercise is most effective in stretching the working muscles when the body is lowered down to a full extension.[5]
A closed grip involves the thumb on the opposite side of the bar from the rest of the fingers. In this position, the forearms are using extra muscles to hold the puller up on the bar.
Chin-ups, like most pull-ups, target the latissimus dorsi muscle as a shoulder extensor, scapular downward rotator and scapular depressor, in bringing the spine to the humerus. This is assisted by elbow flexors (brachialis, brachioradialis, biceps brachii) which bring the humerus to the forearm.
The lat's functions are also assisted, both by shoulder extensors (teres major, posterior deltoid, infraspinatus, teres minor), scapular downward rotators (rhomboids, levator scapulae), and scapular depressors (lower trapezius and pectoralis muscles).
Pulling higher with a narrow grip puts the focus on extension rather than adduction of the shoulder.
If one leans back at the top of the movement, the focus is shifted somewhat towards scapular retraction and hyperextension.
The weight of the legs and pelvis are born by spinal ligaments and various muscles that flex or extend the spine. If the pelvis is tilted anterior and the legs brought behind, the erector spinae (with aid from the lats) bears more weight. If the pelvis is tilted posterior and the legs brought in front, the rectus abdominis (with aid from the psoas) bears more.
Specific training is needed in order to increase chin-ups performance.
The performance can be measured in various ways:
Various organizations like Guinness World Records maintain lists of world records for chin-ups and pull-ups.[6] Both record holders.org and Guinness World Records maintain that Pull-ups use a pronated grip while Chin-ups use a Supinated Grip
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