The Measured Effects of Isometric Loading in a Flexed vs Neutral Lumbar Spinal Position

10

VII

https://doi.org/10.22214/ijraset.2022.45841

July 2022

International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.538 Volume 10 Issue VII July 2022- Available at www.ijraset.com

The Measured Effects of Isometric Loading in a Flexed vs Neutral Lumbar Spinal Position: A Case Report Dr. Brogan Williams PhD, MS, Selinus University of Science and literature, North Shore, Auckland, 0622, New Zealand Abstract: The common understanding that loaded lumbar flexion is a positional hazard and a possible cause for injury has recently been disputed by certain fractions of the manual medicine and exercise science community [1]. Although a polarizing subject, this case study set out to investigate the first hand subjective experience of loaded lumbar flexion on an actual experienced world champion strength athlete. The research question driving this case report was “Does an isometric load applied to a flexed lower back cause more tightness, general discomfort OR pain than that same load applied to a neutral spine?”. A null hypothesis and an Alternative hypothesis was established. For set 1, the participant performed a 30kg dumbbell weighted isometric 45-degree angled hip hinge in lumbar “macro-flexion”. 3 markers were used to gather subjective feedback.

The lifter was instructed to notify the researchers verbally when the onset of tightness, general discomfort, and pain began – each marker was assigned a time. Marker 1; tightness was felt at the 12 second mark. Marker 2; general discomfort was experienced at 49 seconds and marker 3; pain occurred from the 85 second mark, which reached a 7/10 VAS score before stopping at 98 seconds. Additionally, the patient experienced residual LBP following the session. After a 1-week wash out period, the participant performed set 2, a 30kg dumbbell weighted isometric 45-degree angled hip hinge with a “relatively neutral” lumbar position. The lifter exceeded set 1’s max time of 98 seconds experiencing no onset of tightness, general discomfort or pain. The patient did not experience any on-going pain after the session either. The results conclude that a “relatively neutral” lumbar spinal position during a loaded isometric hip hinge was less provocative across all 3 markers. Conversely, set 1 showed a very provocative response, with a rapid early onset of tightness, general discomfort and pain - of which the pain lingered beyond the sessions duration. A strong association between loaded lumbar macro-flexion and the onset of tightness, discomfort and pain was observed in this case study – however, more high quality research is required to reach stronger conclusion.

Keywords: Lumbar flexion; extension; biomechanics; spine; ROM; pain.

I. INTRODUCTION The common understanding that loaded lumbar flexion is a positional hazard and a possible cause for injury has recently been disputed by certain fractions of the manual medicine and exercise science community [1]. Although a polarizing subject, this case study set out to investigate the first hand subjective experience of loaded lumbar flexion on an actual experienced world champion strength athlete. Often the discussion around loaded flexion is reduced to randomised control trials, isolated sEMG results [2], animal studies [3] and research that classifies “load” as lifting a “pen” [1]. However, it is crucial when discussing flexion under “load”, to use load. Furthermore, it is important when discussing how that load impacts strength athletes, to use strength athletes – remember context is key, this is often missed from the literature. What’s more, it is commonly understood that during lifting (squats/hip hinge), one cannot fully avoid spinal flexion [4], [5]. For this reason, in this study we are categorising our two positions as “macro flexion’ – the participant was excessively flexing the lumbar spine to the point is was evident to the naked eye, and “relative neutral” – the participant was making a direct effort to maintain spinal neutrality.

II. CONSENT The participant was required to agree to a consent form prior to partaking in the case report. This was primarily to educate the participant on the study and to ensure they are 18 or above.

III. THE HYPOTHESIS A. Research Question Does an isometric load applied to a flexed lower back cause more tightness, general discomfort OR pain than that same load applied to a neutral spine?

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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.538 Volume 10 Issue VII July 2022- Available at www.ijraset.com B. Null Hypothesis Both position cause a similar amount of tightness, general discomfort and pain under isometric load, indicating one is no worse than the other.

C. Alternative Hypothesis A flexed position under isometric load caused symptoms of tightness, general discomfort and pain to occur sooner and more severe compared to a more neutral position.

IV. METHOD An advanced world champion male powerlifter with no current or recent LBP performed 2 isometric max hold sets loaded with dumbbells in a hip hinge static position of 45 degrees with total weight of 30kg. In both positions the participant held the dumbbells with straight arms and locked out elbows hanging the weight directly below and in line with the shoulders. In position 1 the participant actively flexed his lower back and held that static position. In position 2 the participant actively tried to load the hips and attempt to avoid “macro” lumbar flexion, keeping the lower spine as neutral as possible but still maintaining the same 45-degree angle. Between set 1 and set 2 there was a 1 week wash out period, to avoid accumulative fatigue as a variable that may skew the results.

The participant was timed and was indicated to notify the researcher when he experienced tightness (marker 1), general discomfort (marker 2) and eventually pain (marker 3). Once the participant reached the pain threshold they were asked to stop and the time was ended. The pain was documented via the Visual Analog Scale (VAS) allowing the participant to measure the pain between 1-10.

Fig. 1 Set 1 and Set 2 Mechanical Example

Fig. 2 Visual Analog Scale of Pain

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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.538 Volume 10 Issue VII July 2022- Available at www.ijraset.com V. RESULTS For set 1, the participant performed a 30kg dumbbell weighted isometric 45-degree angled hip hinge in lumbar “macro-flexion”. 3 markers were used to gather subjective feedback. The lifter was instructed to notify the researchers verbally when the onset of tightness, general discomfort, and pain began – each marker was assigned a time. Marker 1; tightness was felt at the 12 second mark. Marker 2; general discomfort was experienced at 49 seconds and marker 3; pain occurred from the 85 second mark, which reached a 7/10 VAS score before stopping at 98 seconds. The patient experienced LBP following this session also.

After a 1-week wash out period, the participant performed set 2, a 30kg dumbbell weighted isometric 45-degree angled hip hinge with a “relatively neutral” lumbar position. The lifter exceeded set 1’s max time of 98 seconds experiencing no onset of tightness, general discomfort or pain. The patient did not experience any on-going pain after the session either.

Fig. 3 Lumbar Intolerance Markers in Flexion Under Load VI. DISCUSSION The results conclude that a “relatively neutral” lumbar spinal position during a loaded isometric hip hinge was less provocative across all 3 markers. Conversely, set 1 showed a very provocative response, with a rapid early onset of tightness, general discomfort and pain - of which the pain lingered beyond the sessions duration. When considering the real-world application of load on an inefficient biomechanical position, it’s clear to see it doesn’t make sense when it is tested within the right context. The amount of force that is being distributed through the musculoskeletal system is immense, and this requires a person to at least try and maintain spinal neutrality. The anecdotal evidence used when debating the negative effects of lumbar flexion under load is immense, so this case study is one more step in the right direction of more research which we desperately need. A large clinical trial is needed, with multiple participants with a background in lifting being tested in lumbar flexion under significant weight. Kinesiology needs to be digitally tracked, sEMG for muscle activation and the inclusion of subjective feedback, as seen in this study. The goal is to continue to build upon this research.

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International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.538 Volume 10 Issue VII July 2022- Available at www.ijraset.com VII. CONCLUSION A strong association between loaded lumbar macro-flexion and the onset of tightness, discomfort and pain was observed in this case study – however, more high quality research is required to reach stronger conclusion.

REFERENCES [1]

[2] [3] [4] [5]

Saraceni, Nic, et al. “To Flex or Not to Flex? Is There a Relationship between Lumbar Spine Flexion during Lifting and Low Back Pain? A Systematic Review with Meta-Analysis.” Journal of Orthopaedic & Sports Physical Therapy, vol. 50, no. 3, Mar. 2020, pp. 121–130, 10.2519/jospt.2020.9218. Accessed 19 June 2020.

Qiao, Jie, et al. “A Study on the Paraspinal Muscle Surface Electromyography in Acute Nonspecific Lower Back Pain.” Medicine, vol. 98, no. 34, Aug. 2019, p. e16904, 10.1097/md.0000000000016904. Accessed 22 Nov. 2021.

Callaghan, Jack P, and Stuart M McGill. “Intervertebral Disc Herniation: Studies on a Porcine Model Exposed to Highly Repetitive Flexion/Extension Motion with Compressive Force.” Clinical Biomechanics, vol. 16, no. 1, Jan. 2001, pp. 28–37, 10.1016/s0268-0033(00)00063-2.

Edington, Corey 1990-. “Lumbar Spine Kinematics and Kinetics during Heavy Barbell Squat and Deadlift Variations.” Harvest.usask.ca, 1 Dec. 2017, harvest.usask.ca/handle/10388/8539.

McGill, Stuart M, and Leigh W Marshall. “Kettlebell Swing, Snatch, and Bottoms-up Carry: Back and Hip Muscle Activation, Motion, and Low Back Loads.” Journal of Strength and Conditioning Research, vol. 26, no. 1, Jan. 2012, pp. 16–27, 10.1519/jsc.0b013e31823a4063. Accessed 5 Aug. 2020.

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