Plank

Movement

What the movement is

The plank is a prone exercise, meaning it is done face-down¹. One study tested face-down and side exercises both on the toes and on the knees¹. One study had people hold each version for 30 seconds⁸. Two of these studies measured muscle activity during the hold, one of them with electromyography (EMG), which picks up a muscle’s electrical signals^1,2.

The versions studies have used

The studies on this page changed the basic plank in several ways^8,9. Each row below names what one study changed, and how many people it tested.

Version	Changed	People tested
Face-down and side exercises on the toes or on the knees	Support at the legs	181
High plank or low plank	Elbow position	217
Long-lever plank with posterior pelvic tilt (tailbone tucked under)	Lever length and pelvis angle	198
Shoulder blade and pelvis positions	Shoulder blade and pelvis angle	1510
Abdominal hollowing added	Belly drawn in	205
Feet raised on wall bars at rising heights	Body tilt	249
Arms, feet or both hung in suspension straps	Support at the arms and legs	213
Instability devices	Surface steadiness	122
Feet in gymnastics rings and elbows on a Bosu ball (a half-ball balance trainer)	Surface steadiness	1611

What it loads

The muscles of the abdomen

Plank studies measured activity in the muscles of the abdomen^1,9. The rectus abdominis lies in the front wall of the abdomen⁶. It is the main muscle that bends the spine forward, as in sitting up⁶. On the flanks, the abdominal wall has three layers of muscle⁶. The external oblique is the outer layer, and the internal oblique is the middle one⁶.

One study compared face-down exercises, the plank on the toes among them, with the crunch and the bent-knee sit-up¹. In 18 men and women aged 23 to 45, the face-down exercises produced similar rectus abdominis and internal oblique activity¹. They produced roughly 10–100% more external oblique activity than the crunch¹.

How the versions shift the work

Changing the plank changed abdominal activity in several small studies^5,8,9. Each finding below comes from one study, with the systematic review’s result added where it has one:

• Toes or knees. In 18 adults, face-down and side exercises done on the toes produced roughly 25–185% more abdominal and oblique activity than on the knees¹.
• Feet raised. In 24 young adults who did recreational gymnastics, planks with the feet raised on wall bars were compared with the feet on the ground⁹. The raised versions produced higher rectus abdominis, external oblique and internal oblique activation⁹.
• Longer body, tucked pelvis. In 19 people, a long-lever plank with posterior pelvic tilt produced greater upper rectus abdominis, lower abdominal and external oblique activation than the usual plank⁸.
• Shoulder blades and pelvis. In 15 people, drawing the shoulder blades together with a posterior pelvic tilt produced more external and internal oblique activity than the other combinations tested¹⁰. The systematic review of healthy adults found this plank had the highest internal oblique activity among core stability exercises⁴. It expressed that activity as a percentage of MVIC, the muscle’s hardest effort while the joint stays still⁴.
• Belly drawn in. In 20 people, abdominal hollowing raised external and internal oblique activity compared with the standard plank⁵.

In the long-lever study, the long-lever part tended to add more to these differences than the pelvic tilt⁸. In the hollowing study, rectus abdominis activation did not differ significantly between the two planks (p = 0.056)⁵.

Unsteady surfaces and straps

In 12 healthy men and women, planks on instability devices raised overall activity in the surface trunk muscles measured, compared with stable planks². Those muscles were the rectus abdominis, external oblique and erector spinae (the group of long muscles beside the spine that straighten the back)². In 21 people, planks with the arms, feet or both hung in suspension straps produced higher abdominal activation than the floor plank³. Activation with the arms hung did not differ from activation with both arms and feet hung³.

The systematic review reports that other researchers saw more external oblique activity when straps or whole-body wobble boards were added to the plank⁴. On the rectus abdominis, the review notes that suspension straps add instability, which could raise EMG activity⁴. It adds that activity may vary with the type of strap system⁴. It names the suspended plank among the exercises it suggests for rectus abdominis activation⁴.

In 16 recreationally active men, rectus abdominis activation was greatest with the feet in gymnastics rings and the elbows on a Bosu ball¹¹.

The back and thigh muscles

The plank studies also measured muscles beyond the abdomen¹. The erector spinae are the main muscles that straighten the back⁶. They make up most of the back’s muscle mass⁶.

The latissimus dorsi is a broad, triangular muscle on the lower back⁶. The rectus femoris is the muscle of the quadriceps at the front of the thigh⁶. It is the only quadriceps muscle that crosses both the hip and the knee¹².

Each finding below comes from one study^1,5:

Muscle	What the studies found
Erector spinae (lower back)	Higher with abdominal hollowing, in 20 people5
Erector spinae	Greater with shoulder blades drawn together and a posterior pelvic tilt, in 15 people10
Latissimus dorsi	About 110–160% more in face-down exercises than in the crunch, in 18 adults1
Rectus femoris	Several times more in face-down exercises than in the crunch, in 18 adults1
Rectus femoris	Greatest with the arms hung in straps, in 21 people3
Latissimus dorsi, lower-back muscles and rectus femoris	More in face-down and side exercises on the toes than on the knees, in 18 adults1

The shoulder muscles

Three studies measured muscles around the shoulder during the plank^3,7,11.

• The serratus anterior is a muscle on the side of the chest that attaches to the upper ribs. In 21 people, its activity peaked in the floor plank and the plank with the feet hung³.
• The trapezius is the large muscle across the upper back and neck that moves the shoulder blade. In 21 healthy men, the high plank produced more lower trapezius activity than the low plank⁷.
• The triceps brachii is the muscle on the back of the upper arm that straightens the elbow. In the same 21 men, it was also more active in the high plank⁷.
• The anterior deltoid is the front part of the deltoid, the muscle that caps the shoulder¹³. In 16 recreationally active men, its activation was greatest on stable ground¹¹.

The shoulder girdle is the shoulder blades and collarbones. Muscles that position it, including the serratus anterior and trapezius, give the arm a steady base to move from⁶.

A single case report

One case report described a person whose shoulder blade stuck out on one side after prone plank exercises¹⁴. This is called scapular winging, and it came from an injury to a nerve called the long thoracic nerve¹⁴. The exercises may have been done incorrectly¹⁴. The authors suggest that greater and incorrect loading of the shoulder blade may have been involved¹⁴.

How the body adapts

What the plank studies measured

Three of the plank studies under What it loads measured muscle activity during planks^1,7,9. The training studies later in this section looked at some of these muscles after training programmes, not after the plank alone^15,16,17,18.

The abdominal muscles

In nine inactive healthy women, rectus abdominis volume was 21% greater after 36 weeks of Pilates training¹⁵. It was measured by MRI, a scan that shows soft tissue such as muscle in detail¹⁵.

A randomised controlled trial assigns people to groups by chance, then compares the groups. In one such trial of 73 people aged 18 to 45, 40 did four weeks of rotational exercise¹⁶. Their external oblique grew thicker on ultrasound, a scan made with sound waves, between the first measurement and each later one¹⁶. The trial’s summary gave no comparison with the group that did not train¹⁶.

In five astronauts across seven six-month missions, the combined thickness of the front and side abdominal muscles fell by 16.2%¹⁹. That combined measure included the external oblique¹⁹. It rose again during a 15-day reconditioning programme back on Earth¹⁹.

The back muscles

In a two-year randomised controlled trial, 27 healthy white women past menopause did progressive back-strengthening exercise¹⁷. Their mean back extensor strength (the strength of the muscles that straighten the back) rose from 39.4 kg to 66.8 kg¹⁷. In the 23 controls, it rose from 36.9 kg to 49.0 kg¹⁷. Eight years after the exercise stopped, the trained group’s strength had fallen to 32.9 kg¹⁷. It was still significantly higher than the controls’ 26.9 kg¹⁷.

The latissimus dorsi

The study group was 18 healthy young adults with no regular resistance training for at least two years¹⁸. Eight weeks of progressive resistance training was followed by gains in latissimus dorsi strength¹⁸. Its cross-sectional area, the size of a slice cut straight across the muscle, also grew¹⁸.

Progressive overload

A 2026 position stand describes progressive overload as the need to increase the stimulus placed on the muscle throughout a training programme²⁰. The plank studies below changed hold time, effort or the version of the plank^21,22,23.

Longer holds and rising effort

One study had 15 resistance-trained people hold a forearm plank for 1, 2 and 3 minutes²¹. Perceived exertion, how hard the effort felt, rose with each longer hold²¹. Only the 3-minute hold raised muscle thickness and echo intensity and lowered peak force, compared with the shorter holds²¹. Echo intensity is how bright a tissue shows on an ultrasound scan, and peak force is the most force produced.

In 15 moderately active people holding a plank to failure, perceived exertion rose significantly from the midpoint²⁴. It correlated strongly with rectus abdominis fatigue on EMG, and moderately with the other core muscles measured²⁴.

Plank training programmes

Of five training studies that described their plank programmes, three made the plank harder over the weeks^22,23,25. One made each session harder as it went on²⁶. One kept a single 30-second plank the same throughout²⁷. The college study set the plank within a core training programme, and the futsal study used it as one of four core exercises, so their results belong to the whole programme^23,25.

Who trained	How the plank changed	What was found
60 older adults, randomly allocated to planks or a control group, for 12 weeks	Effort rose from 60% to 80% of maximal perceived exertion. The target session time rose from 20 to 30 minutes22	Grip strength rose about 18% and sit-ups about 42%. The control group’s values deteriorated22
One man of 43, in a case report, for 4 weeks	Each session had three 10-minute stages, held to a harder perceived exertion in turn26	Strength, endurance, flexibility and heart and lung fitness rose from his starting values26
21 male college athletes, randomly split, for 8 weeks	Holds went from 45 to 60 seconds, then onto an air pad or Bosu ball, then to five variations25	Endurance plank test time rose significantly, from 193.5 to 241.5 seconds, only in the training group25
Professional female futsal (indoor five-a-side football) players, for 6 weeks	Holds went from 30 to 50 seconds over three steps, with first an arm, then an arm and a leg, reached out23	In 14 players, a stable-surface and an unstable-surface group did not differ significantly in any measure23
Three elite female university ice hockey players, in a case series, for 24 weeks	One 30-second plank three times a week, in two 8-week phases split by an 8-week break27	Core stability, side tapping and sit-up scores improved in the plank phases. They plateaued or declined in the break, and sprint and body composition changed little27

Connections

The muscles it works

The plank studies on this page measured these muscles, each with its own entry¹:

• The rectus abdominis, in the front wall of the abdomen^1,6.
• The external oblique, the outer muscle layer on the flank^2,6.
• The erector spinae, the main muscles that straighten the back^5,6.
• The latissimus dorsi, on the lower back^1,6.
• The quadriceps, through its rectus femoris^1,6.
• The deltoid, through its front part^11,13.

Muscles without an entry yet

The internal oblique, serratus anterior, trapezius and triceps brachii were also measured in plank studies^3,7,9.

Sources

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2. Snarr RL, Esco MR (2014). Electromyographical comparison of plank variations performed with and without instability devices.. Journal of Strength and Conditioning Research. doi:10.1519/JSC.0000000000000521 PMID 25264667
3. Byrne JM, Bishop NS, Caines AM, Crane KA, Feaver AM, Pearcey GE (2014). Effect of using a suspension training system on muscle activation during the performance of a front plank exercise.. Journal of Strength and Conditioning Research. doi:10.1519/JSC.0000000000000510 PMID 24796979
4. Oliva-Lozano JM, Muyor JM (2020). Core Muscle Activity During Physical Fitness Exercises: A Systematic Review.. International Journal of Environmental Research and Public Health. doi:10.3390/ijerph17124306 PMID 32560185
5. García-Jaén M, Cortell-Tormo JM, Hernández-Sánchez S, Tortosa-Martínez J (2020). Influence of Abdominal Hollowing Maneuver on the Core Musculature Activation during the Prone Plank Exercise.. International Journal of Environmental Research and Public Health. doi:10.3390/ijerph17207410 PMID 33053717
6. Betts JG, Young KA, Wise JA, Johnson E, Poe B, Kruse DH, Korol O, Johnson JE, Womble M, DeSaix P (2022). Anatomy and Physiology 2e. OpenStax. Link
7. Can EN, Harput G, Turgut E (2024). Shoulder and Scapular Muscle Activity During Low and High Plank Variations With Different Body-Weight-Bearing Statuses.. Journal of Strength and Conditioning Research. doi:10.1519/JSC.0000000000004622 PMID 37815235
8. Schoenfeld BJ, Contreras B, Tiryaki-Sonmez G, Willardson JM, Fontana F (2014). An electromyographic comparison of a modified version of the plank with a long lever and posterior tilt versus the traditional plank exercise.. Sports Biomechanics. doi:10.1080/14763141.2014.942355 PMID 25325773
9. Moreno-Navarro P, Sabido R, Barbado D, Prat-Luri A, Vera-Garcia FJ (2024). Trunk muscle activation in prone plank exercises with different body tilts.. Journal of Back and Musculoskeletal Rehabilitation. doi:10.3233/BMR-230209 PMID 38217576
10. Cortell-Tormo JM, García-Jaén M, Chulvi-Medrano I, Hernández-Sánchez S, Lucas-Cuevas ÁG, Tortosa-Martínez J (2017). Influence of Scapular Position on the Core Musculature Activation in the Prone Plank Exercise.. Journal of Strength and Conditioning Research. doi:10.1519/JSC.0000000000001689 PMID 27787465
11. Sağlam AF, Aydın EM, Demirkan E, Gündoğan B, Favre M (2025). Effects of Surface Stability on Muscle Activation during Plank Exercise.. Journal of Human Kinetics. doi:10.5114/jhk/203417 PMID 42211810
12. Begum FA, Kayani B, Chang JS, Tansey RJ, Haddad FS (2020). The management of proximal rectus femoris avulsion injuries.. EFORT Open Reviews. doi:10.1302/2058-5241.5.200055 PMID 33312709
13. Vohra A, Paul B, Saunders P, Galal Y, Yao S, Hui C, Lederman E, McKee M, Shah A (2024). Anatomic variations of the deltoid muscle insertion: a cadaveric study.. JSES International. doi:10.1016/j.jseint.2024.01.013 PMID 38707574
14. Güzel Ş, Ozen S, Sözay S (2023). Scapula winging secondary to prone plank exercise: a case report.. International Journal of Neuroscience. doi:10.1080/00207454.2021.1924710 PMID 33930995
15. Dorado C, Calbet JA, Lopez-Gordillo A, Alayon S, Sanchis-Moysi J (2012). Marked effects of Pilates on the abdominal muscles. Medicine and Science in Sports and Exercise. doi:10.1249/MSS.0b013e31824fb6ae PMID 22357302
16. Niewiadomy P, Szuścik-Niewiadomy K, Kuszewski M, Kurpas A, Kochan M (2021). The influence of rotational movement exercise on the abdominal muscle thickness and trunk mobility - Randomized control trial.. Journal of Bodywork and Movement Therapies. doi:10.1016/j.jbmt.2021.05.008 PMID 34391272
17. Sinaki M, Itoi E, Wahner HW, Wollan P, Gelzcer R, Mullan BP, Collins DA, Hodgson SF (2002). Stronger back muscles reduce the incidence of vertebral fractures: a prospective 10 year follow-up of postmenopausal women.. Bone. doi:10.1016/s8756-3282(02)00739-1 PMID 12052450
18. Paoli A, Pacelli QF, Cancellara P, Toniolo L, Moro T, Canato M, Miotti D, Neri M, Morra A, Quadrelli M, Reggiani C (2016). Protein Supplementation Does Not Further Increase Latissimus Dorsi Muscle Fiber Hypertrophy after Eight Weeks of Resistance Training in Novice Subjects, but Partially Counteracts the Fast-to-Slow Muscle Fiber Transition.. Nutrients. doi:10.3390/nu8060331 PMID 27258300
19. Hides JA, Lambrecht G, Sexton CT, Pruett C, Petersen N, Jaekel P, Rosenberger A, Weerts G (2021). The effects of exposure to microgravity and reconditioning of the lumbar multifidus and anterolateral abdominal muscles: implications for people with LBP.. The Spine Journal. doi:10.1016/j.spinee.2020.09.006 PMID 32966906
20. Currier BS, D'Souza AC, Singh MAF, Lowisz CV, Rawson ES, Schoenfeld BJ, Smith-Ryan AE, et al (2026). American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews.. Medicine and science in sports and exercise. doi:10.1249/MSS.0000000000003897 PMID 41843416
21. Aleais DAS, Sullivan K, Ferreira P, Marchetti PN, Marchetti PH (2022). Acute Dose-Response of Duration During the Isometric Forearm Plank Exercise on Muscle Thickness, Echo-Intensity, Peak Force, and Perception of Effort in Recreationally-Trained Participants.. International Journal of Exercise Science. doi:10.70252/RDKT2873 PMID 35991937
22. Park S, Choi BH, Jee YS (2023). Effects of plank exercise on respiratory capacity, physical fitness, and immunocytes in older adults.. Journal of Exercise Rehabilitation. doi:10.12965/jer.2346536.268 PMID 38188128
23. Lago-Fuentes C, Rey E, Padrón-Cabo A, Sal de Rellán-Guerra A, Fragueiro-Rodríguez A, García-Núñez J (2018). Effects of Core Strength Training Using Stable and Unstable Surfaces on Physical Fitness and Functional Performance in Professional Female Futsal Players.. Journal of Human Kinetics. doi:10.2478/hukin-2018-0029 PMID 30687433
24. Cruz-Montecinos C, Bustamante A, Candia-González M, González-Bravo C, Gallardo-Molina P, Andersen LL, Calatayud J (2019). Perceived physical exertion is a good indicator of neuromuscular fatigue for the core muscles.. Journal of Electromyography and Kinesiology. doi:10.1016/j.jelekin.2019.102360 PMID 31580987
25. Hung KC, Chung HW, Yu CC, Lai HC, Sun FH (2019). Effects of 8-week core training on core endurance and running economy.. PLoS One. doi:10.1371/journal.pone.0213158 PMID 30849105
26. Park SK, Lee KS, Heo SJ, Jee YS (2021). Effects of High Intensity Plank Exercise on Physical Fitness and Immunocyte Function in a Middle-Aged Man: A Case Report.. Medicina (Kaunas). doi:10.3390/medicina57080845 PMID 34441051
27. Yoneyama H, Fujii S, Kaneko S, Watanabe T (2026). Effects of a Minimal-Dose, Short-Duration Core Training Program on Core Function and Athletic Performance in Elite Female University Ice Hockey Players in Japan: A Case Series.. Cureus. doi:10.7759/cureus.114246 PMID 42719619

Every source the library cites

Changes

• October 23, 2026 Added a Progressive overload section.
• September 29, 2026 Added a figure showing where it sits, links to the exercise pages that load it, and tighter wording in a few places.