Etymology The American English term push-up was first used between 1905 and 1910,  while the British press-up was first recorded between 1945 and 1950.  Body mass supported during push-ups According to the study published in Journal of Strength and Conditioning Research, the test subjects supported with their hands, on average, 69.16% of their body mass in the up position, and 75.04% in the down position during the traditional push-ups. In modified push-ups, where knees are used as the pivot point, subjects supported 53.56% and 61.80% of their body mass in up and down positions, respectively.  Muscles worked While the push-up primarily targets the muscles of the chest, arms, and shoulders, support required from other muscles results in a wider range of muscles integrated into the exercise.  Military recruits will often perform push- ups as part of their physical training. Here, U.S. Marine recruits at Marine Corps Recruit Depot San Diego perform push-ups in May 2005, as a part of their basic recruit training. Abdominals The rectus abdominis and transversus abdominis contract continually while performing push-ups to hold the body off the floor and keep the legs and torso aligned. The rectus abdominis spans the front of the abdomen and is the most prominent of the abdominal muscles. The transversus abdominis lies deep within the abdomen, wrapping around the entire abdominal area. Both muscles compress the abdomen, and the rectus abdominis also flexes the spine forward, although it does not execute this function when performing push-ups. Deltoid The anterior portion of the deltoid muscle is one of the major shoulder-joint horizontal adductors, moving the upper arms toward the chest during the upward phase of a push- up. It also helps control the speed of movement during the downward phase. The deltoid attaches to parts of the clavicle and scapula , just above the shoulder joint on one end, and to the outside of the humerus bone on the other. Along with horizontal adduction, the anterior deltoid assists with flexion and internal rotation of the humerus within the shoulder socket. Chest muscles The push up requires the work of many muscle groups, with one of the primary muscle groups being the chest muscles, the pectoralis major and the minor . These are the two large chest muscles and the main pushing muscle group of the upper body. When pushing and lowering the body during a push up, the pectoralis major is doing most of the work. As a result, these muscles become very strong and can become defined lean muscle after doing push-ups regularly. Stabilizers: back body The push-up depends on stabilizer muscles as you push and lower the body. The erector spinae is the main stabilizer muscle in the back. Made up of 3 muscles including the spinalis, longissmus and iliocostalis. spinalis runs adjacent to the spine, the longissimus runs adjacent to the spinalis and the iliocostalis runs adjacent to the longissimus and over the ribs. 2 muscles called the gluteus medius and gluteus minimus stabilize the upper leg. The medius and minimus sit under the largest butt muscle, the gluteus maximus. Triceps brachii While the anterior deltoids and pectoralis major muscles work to horizontally adduct the upper arms during the upward phase of a push-up, the triceps brachii muscles, or triceps for short, are also hard at work extending the elbow joints so the arms can be fully extended. The triceps also control the speed of elbow-joint flexion during the downward phase of the exercise. The closer together the hands are placed during a push-up, the harder the triceps work. The muscle is divided into three heads — the lateral head, long head and medial head. The lateral and medial heads attach to the back of the humerus bone, and the long head attaches just behind the shoulder socket on one end; all three heads combine and attach to the back of the elbow on the other.  There is a special sub-set of the diamond push-up (so named for the diamond shaped space between the hands when the thumb and forefinger of the left hand is placed on the floor up against the thumb and forefinger of the right hand.) The special version of this push-up is when the diamond is placed directly below the nose instead of the solar plexus. The nose must almost touch the floor in the center of the diamond. This special diamond push-up is done by the United States Marine Corps. The lips must come within 1 inch of the floor while keeping the neck in line with the straight spine to qualify as a valid push-up. This can be verified by placing a 1-inch foam disposable earplug on the floor in the center of the diamond and picking it up with the lips. Forearms Stabilizers include wrist and forearm muscles, the knee extensors, and the hip/spine flexors, which all work isometrically to maintain a proper plank position in the standard prone push-up. Biceps During the push-up exercise, the short head of the biceps brachii muscle acts as a dynamic stabilizer. This means the muscle activates at both ends—the elbow and the shoulder —to help stabilize the joints. Joints and tendons Inner muscles that support the operation of the fingers, wrists, forearms and elbows are also worked isometrically. Some push-up modifications that require to have the arms at different heights effectively engage the rotator cuff. Variations In the "full push-up", the back and legs are straight and off the floor. There are several variations besides the common push-up. These include bringing the thumbs and index fingers of both hands together (a "diamond push-up") as well as having the elbows pointed towards the knees. These variations are intended to put greater emphasis on the triceps or shoulders, rather than the chest muscles. When both hands are unbalanced or on uneven surfaces, this exercise works the body core. Raising the feet or hands onto elevated surfaces during the exercise emphasizes the upper (minor) or lower (major) pectorals, respectively. Raising the hands with the aid of push-up bars or a dumbbell allows for greater range of motion, providing further stress for the muscles. Planche push-ups Planche position An extremely difficult variation is to perform a push-up using only hands, without resting the feet on the floor, i.e., starting from and returning to the planche position. These are known as "planche push-ups". To do this variation, the body's center of gravity must be kept over the hands while performing the push-up by leaning forward while the legs are elevated in the air, which requires great strength and a high level of balance. The entire body weight is lifted in this variation. Knuckle push-ups Another variation is to perform push-ups on the knuckles of the fist, rather than with palms of the hands on the floor. This method is also commonly used in martial arts , such as Karate and Tae Kwon Do , and may be used in boxing training while wearing boxing gloves . The intent, in addition to building strength and conditioning, is to toughen the knuckles, wrist, and forearm in the punching position. This variation also reduces the amount of strain in the wrist, compared to the typical "palms on floor" approach, and so it is sometimes used by those with wrist injuries. Such practitioners will usually perform their knuckle push-ups on a padded floor or a rolled-up towel, unlike martial artists, who may do bare-knuckle push-ups on hard floors. The most knuckle push-ups in one minute is 91 by Ron Cooper (Massachusetts, USA) on 15 December 2016.  Maltese push-up The Maltese push-up is a gymnastic variation of the push- up, in which the hands are positioned further down towards the hips (as opposed to roughly alongside the pectorals ), but with a wide distance between them. Hindu push-up See also: sun salutation The Hindu push-up starts from the " downward dog " yoga position and transitions to a "cobra pose" position. It is also known as a Hanuman , judo , or dive bomber push-up. It is common in Indian physical culture and Indian martial arts , particularly Pehlwani . Guillotine push-up The guillotine push-up is a form of push-up exercise done from an elevated position (either hands on elevated platforms or traditionally medicine balls ) where in the practitioner lowers the chest , head , and neck (thus the name) past the plane of the hands. The goal is to stretch the shoulders and put extra emphasis on the muscles there. Backhanded push-up The backhanded push-up is a form of push-ups performed using the back of the hands, rather than the palms. Currently the record holder of the backhanded push-ups is Bill Kathan who broke the world record in 2010, by performing 2,396 on Valentine's Day . One arm versions A U.S. Army employee demonstrates a one-arm push-up in an extended position. Many of the push-up variations can be done using one arm instead of two. This will further increase the resistance put upon the trainee. The world record for the most one handed push ups in an hour was 1,868 and was set by Paddy Doyle from the United Kingdom. It was recorded in Munster Arms Hotel, Sparkbrook, United Kingdom on the 27 November 1993.  Single-leg push-up Lift one leg up off the ground and do a set. Switch legs on the next set. Narrow-grip push-up Do a normal push-up with your hands just a few inches apart from each other underneath the chest. Clap push-up At the peak of the push-up, push yourself up off the ground and quickly clap in midair. The fast jolting force of clap push-ups will help develop explosive power while also bulking up the pectoral muscles for a more defined chest. Spiderman push-up Do a normal push-up but raise one knee toward the elbow of the same side as you rise. Switch knees with each rep. Also add more stress to your abs with 2 second hold. Other versions There are some less difficult versions, which reduce the effort by supporting some of the body weight in some way. One can move on to the standard push-up after progress is made. "Wall" push-ups are performed by standing close to a wall and pushing away from the wall with the arms; one can increase the difficulty by moving one's feet farther from the wall. "Table" or "chair" push-ups are performed by pushing away from a table, chair, or other object. The lower the object, the more difficult the push-up. One should be sure that the object is securely stationary before attempting to push up from it. "Modified" or "knee" push-ups are performed by supporting the lower body on the knees instead of the toes, which reduces the difficulty. This is useful for warm ups/downs, pyramids/drop sets, endurance training and rehab. It can also be used to train in a more explosive plyometric manner (like clapping push-ups) when one can't perform them with the feet. It can also be used with the 1-arm variations as a transition. "Three phase" push-ups involve simply breaking a standard push up into three components and doing each one slowly and deliberately. Participants usually start face down on the floor with hands outstretched either perpendicular or parallel to the body. The first phase involves the arms being brought palms down on a 90 degree angle at the elbows. The second phase involves the body being pushed into the up position. The third phase is returning to the starting position. This technique is commonly used after a large block of regular push ups, as it poses less stress and requires less effort.