Hollow hold

Movement

The held positions studies have used

The studies cited on this page did not name the hollow hold. Each tested a held position, and each claim below names the one it studied^1,2,3,5:

• A double straight leg lift, lying supine (face-up), with the feet held about 5 cm above a board¹.
• An isometric bilateral leg raise, meaning both legs at once².
• The V-sit, held as a test of how long the trunk flexors (the muscles that bend the trunk forward) can hold³.
• The V-sit, held until failure, when a person can no longer hold it⁵.

How the pelvis was set

One study set the pelvis three ways during the double straight leg lift¹. The 16 men held it with the pelvis tilted forward, in neutral, and tilted back¹. The same men also did a sit-up called the Janda sit-up¹.

How the spine sits in a V-sit

A study of 20 adults compared the V-sit with the prone (face-down) plank³. Both were held as trunk flexor endurance tests³. The lumbar spine (lower back) was bent 28 degrees further forward in the V-sit³. No difference between the two was found in the net low back flexor moment, the turning effect around the lower back³.

What it loads

What the studies measured

Three of the studies used electromyography (EMG), a way of measuring a muscle’s activity by picking up its electrical signals^1,2,5. Their main findings, and one further study’s, each from one study:

Position	People	Finding
Double straight leg lift	16 men	Rectus abdominis activity significantly greater with the pelvis tilted back than forward1
Leg lift and Janda sit-up	16 men	Rectus femoris (the quadriceps muscle at the front of the thigh that also bends the hip) activity lowest in the Janda sit-up1
Isometric bilateral leg raise	18 healthy, active women	Significantly more rectus abdominis activity than the plank2
V-sit	30 adults	No difference detected from the prone plank in four trunk muscles3
V-sit, held until failure	17 healthy people	Activity isolated to the abdominal part of the lower back, pelvis and hips5

The rectus abdominis

The rectus abdominis lies toward the middle of the front wall of the abdomen⁴. The rectus sheath, a layer of connective tissue, covers it⁴. It is the prime mover, the main muscle, for bending the vertebral column (the spine) forward, as in sitting up⁴.

In 18 healthy, active women, an isometric leg raise with both legs produced significantly more rectus abdominis activity than the plank². In 16 men doing the double straight leg lift, its upper and lower parts were significantly more active with the pelvis tilted back than forward¹. The same men also did the Janda sit-up¹.

In 18 healthy, active women, an isometric leg raise with both legs produced significantly more rectus abdominis activity than the plank.

A different comparison found no difference³. In 30 adults holding a V-sit and a prone plank, no difference was detected between them in rectus abdominis activity³. The same held for the internal oblique, the middle of the three muscle layers on each side of the abdomen^3,4. It also held for the lumbar (lower back) part of the erector spinae, the long muscles beside the spine that straighten the back³.

The external oblique

The external oblique is the outermost of the three muscle layers on each side of the abdomen⁴. OpenStax names the external and internal obliques as prime movers for twisting at the waist and for bending the spine to the side⁴.

In the 30 adults holding a V-sit and a prone plank, no difference was detected in external oblique activity either³. In 17 healthy people holding a V-sit until failure, sensors recorded seven muscles, including the rectus abdominis and external oblique⁵. The V-sit produced activity isolated to the abdominal part of the lower back, pelvis and hips⁵.

A study of 20 women with low back pain and 20 without measured muscle thickness by ultrasound, a scan made with sound waves⁶. The finding concerned the external oblique and the transversus abdominis, the deepest of those three layers^4,6. At the point of fatigue in a supine double straight-leg raise test, the pattern of thickness change differed between the two groups⁶.

The rectus femoris

The rectus femoris is the front muscle of the quadriceps, the group of four muscles on the front of the thigh⁴. It is the only quadriceps muscle that crosses two joints⁷. It bends the hip as well as straightening the knee⁷. In the study of 16 men, the Janda sit-up showed lower rectus femoris activity than the double straight leg lift¹.

How the body adapts

The EMG studies above measured muscle activity during the hold, not change over weeks of training^1,2,5. One study of each measured the size of two of the muscles it works, before and after other kinds of training^8,9:

• Rectus abdominis. In nine inactive, healthy women, rectus abdominis volume on MRI (a detailed scan of soft tissue) was 21% greater after 36 weeks of Pilates⁸.
• External oblique. In a randomised controlled trial of 73 people aged 18 to 45, 40 did four weeks of rotational exercise, 16 sessions in total⁹. Their external oblique thickness on ultrasound rose significantly from the first measurement to each later one⁹.

Progressive overload

A 2026 position stand describes progressive overload as the need to increase the stimulus placed on the muscle throughout a training programme¹⁰. In the four programmes below that trained the hollow hold, it was one exercise among several, so results belong to that programme^11,12,13,14.

Longer holds in a school programme

One study randomly assigned boys aged 14 to 15 to two groups¹¹. Nineteen did a 6-week isometric programme in physical education lessons, and 21 did regular lessons¹¹. Each session had six isometric exercises, and the hollow body was one of them¹¹.

Volume rose through more circuits, longer holds and longer rests¹¹:

• Week 1: two circuits of 10-second holds, with 5 seconds of rest¹¹.
• Week 6: three circuits of 30-second holds, with 15 seconds of rest¹¹.

A boy who could not hold for the full time was encouraged to finish with one brief pause¹¹. If he needed more pauses, the exercise was stopped¹¹. The two groups did not differ significantly in how body composition, functional outcomes or blood pressure changed¹¹. An isometric mid-thigh pull and a standing broad jump improved whichever group the boys were in¹¹.

Sets, time and rest in other programmes

Three other trials listed the hollow body hold in their programmes^12,13,14:

Who trained, and for how long	What the programme did
24 emergency responders (firefighters and paramedics), 16 weeks, supervised12	A sample session listed a 20-second hollow body hold for 3 sets12. People started at a rating of perceived exertion (a score for how hard effort feels) of 5 or 6 out of 1012. They were then encouraged to add repetitions or weight, or cut rest between supersets (exercises done back to back)12
79 resistance-trained men and women, 10 weeks, three times a week13	Core holds lasted 20 to 45 seconds, depending on training level13. Weeks 1 to 9 had 3 sets with 1 minute of rest13. Week 10 had 2 sets, as a deload week (a planned spell of lighter training)13
42 male soccer players aged 18 to 25 with dynamic knee valgus (the knee moving inward during a movement), 8 weeks, three sessions a week14	A supervised core stability programme progressed by raising the duration or repetitions of each exercise14

In the emergency responders, training effects were similar between the functional and conventional programmes¹². Both raised isometric back extension strength, by 21.3% and 20.3%¹². The hollow body hold appeared in the functional programme’s sample sessions¹².

Hold time as a test

A randomised trial assigned 58 recreationally active, healthy young adults to bodyweight training for 6 weeks¹⁵. The three protocols took 16, 27 or 90 minutes a week¹⁵. Hollow hold time was tested as a measure of muscular endurance: how long a muscle can repeat an effort before it tires¹⁵. It showed a significant effect of time, with no significant difference between the groups¹⁵.

Connections

The muscles it works

• The rectus abdominis, the main muscle bending the spine forward^2,4.
• The external oblique, the outermost muscle layer on the side of the abdomen, recorded during a V-sit held until failure^4,5.
• The rectus femoris, part of the quadriceps, which bends the hip and was measured in the leg lift^1,7.

Positions it was compared with

The studies compared these held positions with the plank and the Janda sit-up^1,2,3. In 18 active women, the leg raise drew more rectus abdominis activity than the plank². In 30 adults, the V-sit and plank did not differ detectably in four trunk muscles³.

Sources

1. Workman JC, Docherty D, Parfrey KC, Behm DG (2008). Influence of pelvis position on the activation of abdominal and hip flexor muscles.. Journal of Strength and Conditioning Research. doi:10.1519/JSC.0b013e3181739981 PMID 18714231
2. Park DJ, Park SY (2019). Which trunk exercise most effectively activates abdominal muscles? A comparative study of plank and isometric bilateral leg raise exercises.. Journal of Back and Musculoskeletal Rehabilitation. doi:10.3233/BMR-181122 PMID 30856100
3. Musalem LL, Stankovic T, Glisic D, Cook GE, Beach TA (2015). Biomechanical and Electromyographic Comparisons of Isometric Trunk Flexor Endurance Test Postures: Prone Plank Versus V-Sit.. Journal of Applied Biomechanics. doi:10.1123/jab.2014-0197 PMID 26252077
4. 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
5. Devorski L, Bazett-Jones DM, Mangum LC, Glaviano NR (2022). Muscle Activation in the Shoulder Girdle and Lumbopelvic-Hip Complex During Common Therapeutic Exercises.. Journal of Sport Rehabilitation. doi:10.1123/jsr.2020-0485 PMID 34525451
6. ShahAli S, Arab AM, Ebrahimi E, ShahAli S, Rahmani N, Negahban H, Kazemnejad A, Bahmani A (2019). Ultrasound measurement of abdominal muscles during clinical isometric endurance tests in women with and without low back pain.. Physiotherapy Theory and Practice. doi:10.1080/09593985.2018.1441345 PMID 29482405
7. 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
8. 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
9. 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
10. 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
11. Koźlenia D, Szafraniec R, Jarosz J, Mazur L, Domaradzki J (2026). Health-Related Effects of a Short Isometric Exercise Program Integrated into School Physical Education: The Role of Biological Maturation and Baseline Functional Status.. Healthcare (Basel). doi:10.3390/healthcare14020161 PMID 41595297
12. Kong PW, Kan TYW, Mohamed Jamil RAGB, Teo WP, Pan JW, Hafiz Abd Halim MN, Abu Bakar Maricar HK, Hostler D (2022). Functional versus conventional strength and conditioning programs for back injury prevention in emergency responders.. Frontiers in Bioengineering and Biotechnology. doi:10.3389/fbioe.2022.918315 PMID 36159702
13. Gavanda S, Held S, Schrey S, Oberwetter K, Lazzaro PM, Pergelt M, Geisler S (2025). Optimizing Resistance Training Outcomes: Comparing In-Person Supervision, Online Coaching, and Self-Guided Approaches: A Randomized Controlled Trial.. Journal of Strength and Conditioning Research. doi:10.1519/JSC.0000000000005216 PMID 40728831
14. Samakosh HMN, Maktoubian M, Doost SPR, Oliveira R, Badicu G, Al-Mhanna SB, Hassanzadeh M, Amadekhiar P, Vaskasi RR (2025). Active and sham transcranial direct-current stimulation (tDCS) plus core stability on the knee kinematic and performance of the lower limb of the soccer players with dynamic knee valgus; two armed randomized clinical trial.. AIMS Neuroscience. doi:10.3934/Neuroscience.2025017 PMID 41103970
15. Aube JJ, Mendolia PJ, Storoschuk KL, Wyman E, Peberdy MD, Wu JJ, Simpson-Stairs N, Swinton PA, Gurd BJ (2026). How Much Is Enough: A Randomized Non-Inferiority Trial Comparing Three Bodyweight Training Protocols.. Journal of Functional Morphology and Kinesiology. doi:10.3390/jfmk11020240 PMID 42346769

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.