The science of Push-ups
This is not a comprehensive review of all the scientific literature about push-ups. It’s a compilation of recent articles and some others that I found interesting or that would be good for discussion.
Feel free to ask for more details!
TL;DR (edit 2)
- close push-ups use more triceps and pecs
- fast push-ups and close push-ups are more stressful for your elbows
- close fists are less stressful for your wrists
- energy drinks pre-workout don't increase push-up max reps
- push-ups activate the same muscles as bench press, but with my core activation, and induce similar hipertrophy (with bench press at
40% of BW40% of 1 RM) - it's possible but rare to get injured doing push-ups
Technique
Kim et al, 2016 assessed the difference of muscle activation using distinct palmar widths and concluded:
Pectoralis minor, triceps brachii, and infraspinatus muscle activities were greater during push-ups performed with the 50% palmar width compared with the other palmar widths. Pectoralis major muscle activity was greater during push-ups performed with the 50% and 100% palmar widths compared with the 150% palmar width. Serratus anterior muscle activity was greater during push-ups performed with the 150% palmar width compared with the other palmar widths.
A great review by Dhahbi et al, 2018 follows. They searched the literature to review all previous research on kinetic analysis of push-ups. They included 26 studies in their analysis. These are the conclusions:
- The force supported by the elbows flexed is significantly greater (8–20% BW) than that with the elbows extended.
- The load supported by one limb ranged from 6% BW for prayer push-ups to 60% BW for one-arm push-ups.
- The clap push-up imposed the highest Peak Force.
- Fast push-ups and push-ups with the shoulder adducted (e.g., diamond push-ups) resulted in the highest peak elbow flexion moments.
- Suspended push-ups resulted in the highest vertebral-joint compressive forces, which can be relevant in people with previous lower back injuries.
- Except for suspended push-up variations, the lateral and medial elbow-joint force, the peak force and rate of impact force are greater on the dominant limb than on the non-dominant limb.
- The push-ups with less wrist and elbow-joint stress are the ones that adopt a neutral hand position (i.e., closed fists).
Because peak power is produced by different combination of force and velocity, push-ups without external loading may be more beneficial when a quick movement speed is desirable, and push-ups with external loading may be more beneficial when a greater force production is required.
Comparison with bench-press
Kikuchi et al, 2017 found that push-up training induced similar increases in muscle thickness of the triceps and pectoralis major to the 40% 1RM bench press. Similar strength gains were also observed in both groups.
Gottschall et al, 2018 compared different muscles activation on bench-press and push-ups and concluded:
the common difference between closed versus open chain exercises for all three hand positions was the 50% greater activity in the anterior core muscles during push-ups. Thus, closed chain exercises may be preferred for functional training.
While a push-up requires more activation of the core, it is not as easy to increase the activation of the primary muscle groups during this body weight exercise. Stated simply, the intensity and muscle activity during a push-up is limited by body weight as well as anthropometry.
They also compared knee with toe push-ups, concluding:
the ratio of activity for each individual muscle as a percentage of total activity for the exercise was not statistically different between the toe and knee push-ups. (…) Thus, knee push-ups are an effective substitute for individuals who cannot successfully or safely complete a toe push-up, and can be incorporated in these scenarios.
Energy drinks?
Magrini et al, 2016 showed no improvement in number of push-ups with the use of a pre-workout beverage (Redline) when compared with placebo, however both groups successfully increase number of reps.
Safety
There are some case reports of injuries correlated with push-ups:
Meena et al, 2014 report an ulnar fracture (forearm) in a 24-year-old cricketer that used to do daily push ups for about one hour in the morning and evening.
Hassan et al, 2011 report an intraocular hemorrage (Valsalva retinopathy) in a 18-year-old man after a few rounds of push-ups.
Keah et al, 2009 reported a rhabdomyolisis case on a 33 year old, sedentary woman, that during a company motivation course was instructed by the speaker to do 90 push-ups as a penalty for losing in one of the events.
De la Fuente et al 2008 report a bilateral shoulder dislocation after a session of 100 push-ups.
References
De la Fuente, F. A., Hoyte, C., & Bryant, S. M. (2008). Push-ups may be hazardous to your health: an atraumatic etiology for bilateral shoulder dislocation. The American Journal of Emergency Medicine, 26(1), 116.e3–116.e4.
Dhahbi, W., Chaabene, H., Chaouachi, A., Padulo, J., G Behm, D., Cochrane, J., … Chamari, K. (2018). Kinetic analysis of push-up exercises: a systematic review with practical recommendations. Sports Biomechanics, 1–40. doi:10.1080/14763141.2018.1512149
Gottschall, J. S., Hastings, B., & Becker, Z. (2018). Muscle Activity Patterns Do Not Differ Between Push-Up and Bench Press Exercises. Journal of Applied Biomechanics, 1–20.doi:10.1123/jab.2017-0063
Hassan M, Tajunisah I. Valsalva haemorrhagic retinopathy after push-ups. Lancet (London, England). 2011;377(9764):504.
Hinshaw, T. J., Stephenson, M. L., Sha, Z., & Dai, B. (2018). Effect of External Loading on Force and Power Production During Plyometric Push-ups. Journal of Strength and Conditioning Research, 32(4), 1099–1108. doi:10.1519/jsc.0000000000001953
Keah S, Chng K. Exercise-Induced Rhabdomyolysis with Acute Renal Failure After Strenuous Push-UPS. Malaysian family physician : the official journal of the Academy of Family Physicians of Malaysia. 2009;4(1):37-9.
Kikuchi N, Nakazato K. Low-load bench press and push-up induce similar muscle hypertrophy and strength gain. Journal of exercise science and fitness. 2017;15(1):37-42.
Kim YS, Kim DY, Ha MS. Effect of the push-up exercise at different palmar width on muscle activities. Journal of physical therapy science. 2016;28(2):446-9.
Magrini MA, Colquhoun RJ, Dawes JJ, Smith DB. Effects of a Pre-workout Energy Drink Supplement on Upper Body Muscular Endurance Performance. International journal of exercise science. 2016;9(5):667-76.
Meena S, Rastogi D, Solanki B, Chowdhury B. Stress fracture of ulna due to excessive push-ups. Journal of natural science, biology, and medicine. 2014;5(1):225-7.
edit: formatting