The core of the issue: Plank performance and pain in the lower back

Key Points

1. Effective spinal segmental stability is linked with coordinated recruitment of the hip muscles, abdominals, and spinal extensor groups.
2. Core stability refers to the coordinated control of the muscles to maintain spinal and postural alignment during static or dynamic tasks.
3. An example of isometric core stability is a static plank, and dynamic core stability is bridging.

BACKGROUND AND OBJECTIVE

Low back pain (LBP) remains the global leading disabling condition despite decades of research and treatment interventions. Recurrence of LBP one year after a previous episode ranges from 24% to 80% (1). There is no clear prediction of who will have a recurrence. Core control and coordination has been a staple of LBP treatment for decades. The authors of this study propose that identifying specific functional impairments of the core musculature may help development of better targeted and meaningful interventions.

The authors point out that the forearm plank is typically used clinically to assess and measure core endurance and trunk control. They argue that it may not be relevant given the isometric component and emphasis on the anterior core musculature. This study looks at the relationship of plank duration and self-reported LBP and compares plank duration with the ability to perform a single leg bridge to see which is a better metric of muscular imbalance in individuals with LBP. Their primary hypothesis was that individuals with LBP would have significantly shorter plank times than those without LBP.

Recurrence of low back pain one year after a previous episode ranges from 24% to 80%; and there is no clear prediction of who will have a recurrence.

Core stabilization needs to be dynamic to allow for function in daily tasks and isometric holds have limited functional carryover but can be a good place to start when movement is too much to control.

METHODS

• This is a cross-sectional study of 117 adults recruited through convenience sampling sourced from university emails. Participants completed a plank endurance test (see Video 1), the modified Oswestry, and a self-report of the presence of LBP.

• Forearm plank timing in a simple trial was completed when neutral alignment could not be maintained or the participant voluntarily stopped.

• A subset of 54 participants with LBP completed phase two, performing a single-leg bridge test on both right and left legs (see Video 1). Participants were included in the analysis if they had a valid date for right and left bridge and a recorded plank hold time. The ratio of bridge to plank was calculated with an average of the single leg scores divided by the plank hold.

• The authors propose that this provides information on the balance between posterior chain (bridge) and anterior (plank) core endurance.

VIDEO 1 – CORE STABILITY TESTS

RESULTS

• Plank hold duration:
  Individuals with LBP had a significantly longer hold duration than those without LBP.

• Bridge to plank ratio: Participants with greater relative posterior chain endurance (single leg bridge average time) reported lower levels of perceived disability.

LIMITATIONS

There is no EMG or movement analysis in the study. The authors propose further study to clarify the balance of mechanisms regarding anterior or posterior chain involvement or alteration of normal movement patterns. Until such further studies can be completed, these results should be taken as correlational and not proving causality.

CLINICAL IMPLICATIONS

The study suggests that increased plank (anterior core) endurance is not necessarily protective against LBP. There would need to be EMG or movement analysis studies to clarify the importance of anterior core endurance, and to assess if the plank is the best clinical indicator (2). It is possible that a more balanced approach to core control would be bridging, in this study tested as single leg bridges to target the posterior chain musculature (3).

Dynamic lumbar stabilization is an old model that I first saw in the clinic in handout form from the San Franscisco Spine Institute, referring to the timing and coordination of the musculature to stabilize during activity. Core stabilization needs to be dynamic to allow for function in daily tasks and isometric holds have limited functional carryover but can be a good place to start when movement is too much to control.

Clinical options include bridging, bridging with small steps, bridging with leg extension, single leg bridges, lunges, multidirectional dynamic balance drills, and sport specific control drills. An important consideration in choosing dynamic stabilization exercises is to have the individual find the exercises to be meaningful and relevant to their daily activities.

+STUDY REFERENCE

Eimiller K, LeFevre L, Robarge C, STrano C, Tarbrake K, Wittman I (2025) ‘The core of the issue: Plank Performance and pain in the lower back’, Journal of Clinical Medicine, 14(11), 3926.

SUPPORTING REFERENCE

1. Hoy, D. et al. (2010) ‘The epidemiology of low back pain’, Best Practice Research Clinical Rheumatology, 24(6), pp. 769–781.
2. Park, D.-J. and Park, S.-Y. (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, 32(5), pp. 797–802.
3. Calatayud, J. et al. (2019) ‘Tolerability and muscle activity of core muscle exercises in chronic low-back pain’, International Journal of Environmental Research and Public Health, 16(19), p. 3509.