Hamstring flexibility cannot predict lumbar joint use in reaching

PainSci » bibliography » Johnson et al 2010
updated Jan 29, 2020

Tags: treatment, self-treatment, stretch, structuralism, etiology, back pain, flexibility, exercise, muscle, biomechanical vulnerability, risks, pro, pain problems, spine

Three pages on PainSci cite Johnson 2010: 1. Quite a Stretch 2. The Complete Guide to Low Back Pain 3. Tight hamstrings, back pain, and movement

PainSci commentary on Johnson 2010: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.

Is there any connection between hamstring flexibility and the amount of lumbar movement when reaching forward? You’d think so, and you’d be right … about healthy people. Not so much in folks with back pain! This straightforward study was so simple that the results are hard to argue with: “Hamstring flexibility is not strongly related to the amount of lumbar flexion used to perform forward-reaching tasks in participants who have chronic LBP or who have recovered from LBP.” In other words, some low back pain patients use their lumbar joints when they reach, and some don’t, and good luck predicting which ones based on hamstring flexibility. You’ll fail if you try, this data says. So that’s how it is. But why and what does it mean? That’s a lot trickier, of course, but it generally suggests the relevance of hamstring extensibility to back pain and function isn’t exactly potent.

The lack of correlation persisted even after recovery, which is particularly interesting. But also mostly uninterpretable without more information (like how long that effect lasts).

~ Paul Ingraham

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

OBJECTIVE: To examine the correlation between hamstring flexibility and hip and lumbar spine joint excursions during standardized reaching and forward-bending tasks.

DESIGN: Retrospective analysis of data obtained during 2 previous prospective studies that examined kinematics and kinetics during forward-reaching tasks in participants with and without low back pain (LBP).

SETTING: The 2 previous studies were conducted in the Motor Control Lab at Ohio University and the Orthopaedic Ergonomics Laboratory at The Ohio State University.

PARTICIPANTS: Data from a total of 122 subjects from 2 previous studies: study 1: 86 subjects recovered from an episode of acute LBP (recovered) and study 2 (A.I. McCallum, unpublished data): 18 chronic LBP subjects and 18 healthy-matched controls (healthy).

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURE: Correlation values between hamstring flexibility as measured by straight leg raise (SLR) and amount of hip and lumbar spine joint excursions used during standardized reaching and forward-bending tasks.

RESULTS: No significant correlation was found between hamstring flexibility and hip and lumbar joint excursions during forward-bending tasks in the LBP or recovered groups. The SLR had a significant negative correlation with lumbar spine excursions during reaching tasks to a low target in the healthy group (right SLR: P=.011, left SLR: P=.004).

CONCLUSIONS: Hamstring flexibility is not strongly related to the amount of lumbar flexion used to perform forward-reaching tasks in participants who have chronic LBP or who have recovered from LBP. More research needs to be conducted to examine the influence of hamstring flexibility on observed movement patterns to further evaluate the efficacy of flexibility training in the rehabilitation of patients with LBP.

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

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