Biological Risk Indicators for Recurrent Non-Specific Low Back Pain in Adolescents

Research Review: Biological Risk Indicators for Recurrent Non-Specific Low Back Pain in Adolescents

By Amy Martinez DPT, PT

Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Jones, M. A., Stratton, G., Reilly, T., & Unnithan, V. B. (2005). Biological risk indicators for recurrent non-specific low back pain in adolescents. British Journal of Sports Medicine, 39(3), 137-140. - ARTICLE

Why the Study is Relevant: The prevalence of recurrent non-specific low back pain (NSLBP) is increasing in adolescents (1) and may increase recurrence in adulthood (2). This 2005 study by British and U.S. researchers investigated the relationship between biological risk indicators, such as lumbar spine and hip range of motion, and recurrence of NSLBP in adolescents. The findings suggest that a decrease in spine mobility and trunk muscle endurance are correlated with NSLBP. Human movement professionals may be able to use these indicators to identify adolescents at risk of NSLBP, and create preventative programs to reduce the risk of future occurrence.

Caption: Illustration of a skeleton with low back pain zone highlighted.

Region of low back pain. (Image: By LadyofHats Mariana Ruiz Villarreal - i did it myself, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1530655)

Study Summary

Study Design	Matched Case-Control Study
Level of Evidence	III Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies and case-control studies
Participant Characteristics	Demographics Number of participants: 56 (28 each in the study and control groups) Age: 14.9 +/- 0.7 years Gender: 26 female and 30 male Adolescents with recurrent NSLBP and matched control participants with no history of low back pain Inclusion Criteria: Symptomatic study group: adolescents self-identified via questionnaire as having recurrent NSLBP Asymptomatic control group: adolescents self-identified via questionnaire as having no history of NSLBP Exclusion Criteria: Asymptomatic control group: prior history of NSLBP
Methodology	Participants filled out a questionnaire to assess the prevalence of NSLBP Asymptomatic control group participants were identified through class lists and reported no history of NSLBP Prior to testing, participants in the asymptomatic control group and those in the symptomatic study group were matched for chronological age, sex and school class Prior to testing, written informed parental consent and the participants' verbal assent were obtained A series of measurements were taken from participants in both groups by a single researcher who was not blinded to group allocation Anthropometric Measurements Stature, mass and sitting height were measured following standardized procedures to the nearest 0.1 cm, 0.1 kg and 0.1 cm respectively Body mass index was calculated as mass divided by stature squared Skinfold measurements were taken from four sites: biceps, triceps, suprailiac and subscapular via calibrated Harpenden skinfold calipers, and a mean was calculated from duplicated measurements at each site Sexual Maturity Assessment Sexual maturity was measured via self-assessment after participants observed drawings of stages of secondary sex characteristics during puberty: Females were shown representations of 5 stages of breast development and 4 stages of pubic hair development; males were shown 5 stages of genital development and 4 stages of pubic hair development Flexibility/Spinal Mobility Measurements The modified Schöber procedure was used to measure lumbar flexion and side bending for lateral flexion of the spine The Leighton Flexometer was used to measure hip range of motion with the knee extended The sit and reach test was performed Abdominal Muscle Endurance Assessment Abdominal muscle endurance was assessed using the 60-second sit-up test
Data Collection and Analysis	Statistical Analysis A backward conditional stepwise logistic regression was performed for the following predictor variables with p>0.10 used at each step of analysis: Sitting height Body mass index Sum of four skinfolds Pubic hair rating Genital rating Sit and reach Hip range of motion Lumbar flexibility in the sagittal plane Lateral flexion of the spine (composite of right and left sides) Trunk muscle endurance The significance of each coefficient within the model was evaluated using Wald tests The fit of the regression equation was tested using the Hosmer-Lemeshow goodness of fit and chi square analysis The risk indicators of recurrent NSLBP that were identified from the logistic regression were then analyzed in a univariate analysis Significance was set at p<0.05 for the univariate analysis A two-way ANOVA was performed for each risk indicator to assess the magnitude of the difference between the symptomatic and asymptomatic groups and to investigate the effect of sex
Outcome Measures	History of non-specific low back pain Hip range of motion Number of sit ups (abdominal muscular endurance) Lumbar flexion Lateral flexion of the spine
Results	Logistic Regression Analysis The logistic regression identified hip range of motion, number of sit ups, lumbar flexibility and lateral flexion of the spine as significant risk indicators of recurrent NSLBP in adolescents The Hosmer-Lemeshow goodness of fit test revealed no significant difference between the observed and expected predictions for low back pain Univariate Analysis The two-way ANOVA identified the symptomatic study group as having significantly lower abdominal muscular endurance (completed 5.1 fewer sit ups), lateral flexion of the spine (23.1 mm less flexibility) and lumbar flexion (7.3 mm less flexibility) than the asymptomatic control group When the magnitude of the differences between the study and control groups was interpreted in relation to the measurement error associated with the variables, lateral flexion of the spine and lumbar flexion were found to be greater in magnitude than the measurement. Abdominal muscular endurance was similar in magnitude to the random error associated with the measure. The two-way ANOVA for hip range of motion revealed no significant group effect, as a 2.8 degree difference in hip range of motion between the study and control groups lacked statistical significance Significant sex effects were observed for all of the measures. The females had increased flexibility and spinal mobility compared with the males, but reduced abdominal muscle endurance (p<0.05) No significant interaction effects were identified between the effects of sex and low back pain (p>0.05), suggesting that risk indicators were similar for both sexes
Our Conclusions	The researchers' conclusions add to the Brookbush Institute's predictive models of postural dysfunction and support the role of exercise in prevention and rehabilitation programs. The reduction in spinal flexibility, abdominal muscle endurance and hip range of motion in adolescents with NSLBP may be further evidence of the relative changes in activity described in the predictive model of Lumbo Pelvic Hip Complex Dysfunction (LPHCD).
Researchers' Conclusions	Hip range of motion, abdominal muscle endurance, lumbar flexibility and lateral flexion of the spine were the best predictors of recurrent NSLBP in a group of adolescents. Symptomatic study participants had significantly reduced spinal mobility and trunk muscle endurance compared with the asymptomatic control participants. This finding suggests that these are the most important biological risk indicators examined, and identify a potential role for exercise as a primary or secondary prevention strategy.

Caption: Anterior Pelvic Tilt during Overhead Squat Assessment

Anterior Pelvic Tilt during Overhead Squat Assessment. (Image: Courtesy of www.BrentBrookbush.com)

Review & Commentary:

This study adds to the body of research investigating relationships between biological risk indicators and non-specific low back pain (NSLBP). The findings reinforce the correlation between limited hip flexion, lumbar flexion, lateral flexion of the spine and decreased trunk muscle endurance and low back pain (LBP) (3). The authors' objective investigation of biological risk indicators in adolescents with NSLBP was unique; previous studies evaluated only psychosomatic risk indicators (4, 5). These findings contribute to a model of Lumbo Pelvic Hip Complex Dysfunction (LPHCD) which may aid human movement professionals in identifying NSLBP and developing prevention and rehabilitation programs.

The study had many methodological strengths, including:

The methodology was strong for a case-control study. The researchers matched the participants in each group and controlled for variables, such as age and gender, that could contribute additional variances to the outcomes.
The same researcher obtained all measures for all participants, enhancing the reliability of data collection.
This study filled a gap in the body of research by demonstrating a relationship between biological risk indicators for NSLBP in adolescents and lumbar flexion, lateral flexion of the spine, trunk muscle endurance and hip range of motion.

Weaknesses that should be noted prior to clinical integration of the findings include:

This study did not include an intervention (by design) and was purely observational. Future research that included intervention for identified biological risk indicators may better support practical application.
The acute, cross-sectional nature of the study limits speculation on the long-term relevancy of the biological risk indicators and suggests a need for further testing.
The examiner was not blinded to the group allocation prior to testing, which may have increased tester bias.
All the participants were adolescents. Similar trends may not be present in adults, thus reducing generalizability and suggesting a need for further study.
Inclusion criteria were based on subjective reporting of NSLBP. Future studies should include objective and/or functional data, as well as subjective reporting to improve the classification of individuals with NSLBP.

How This Study is Important:

The increasing prevalence of adolescent recurrent NSLBP (1) may lead to increased recurrent NSLBP in adults (2). The investigation of biological risk indicators in adolescents with NSLBP was unique to this study; previous studies evaluated only psychosomatic risk indicators (4, 5). This study demonstrates correlation with decreased abdominal muscle endurance, lumbar flexibility, lateral flexion of the spine and hip range of motion. This and similar research may aid in the development of prevention and rehabilitation programs in populations with NSLBP.

How the Findings Apply to Practice:

Human movement professionals should consider Lumbo Pelvic Hip Complex Dysfunction (LPHCD) as multifactorial, and be aware of evidence-based correlations and risk factors associated with NSLBP. This should inform the assessments and interventions selected for this patient population, specifically for identifying and addressing abdominal muscle endurance, lumbar flexibility, lateral flexion of the spine and hip range of motion.

How does it relate to Brookbush Institute Content?

The Brookbush Institute's predictive models of postural dysfunction are constructed "with the premise that understanding the common tissue changes (muscle, joint, fascia and nerve) associated with each postural dysfunction will aid in selection of an optimal set of assessments and techniques." This study provides further evidence of common changes found in a population of adolescents with recurrent NSLBP, specifically decreased spinal mobility, trunk muscle endurance and hip range of motion. This is consistent with changes in osteokinematics and muscle activity as proposed in the Brookbush Institute's predictive model of Lumbo Pelvic Hip Complex Dysfunction (LPHCD) . Human movement professionals should incorporate a comprehensive assessment of lumbar spine range of motion, trunk muscle endurance testing and hip range of motion when selecting intervention strategies for individuals with NSLBP.

The following videos illustrate common assessment techniques, including a dynamic/transitional posture assessment; signs of dysfunction; hip flexion goniometry; and interventions to address abdominal muscle activation and dynamic strengthening.

Introduction to Overhead Squat Assessment

Overhead Squat Assessment: Sign Clusters - Lumbo Pelvic Hip Complex Dysfunction

Hip Flexion Goniometry

Transverse Abdominis TVA Isolated Activation

Ball Crunch and Progressions

Bibliography:

Hakala, P., Rimpelä, A., Salminen, J. J., Virtanen, S. M., & Rimpelä, M. (2002). Back, neck, and shoulder pain in Finnish adolescents: national cross sectional surveys. Bmj, 325(7367), 743.
Salminen, J. J., Erkintalo, M. O., Pentti, J., Oksanen, A., & Kormano, M. J. (1999). Recurrent low back pain and early disc degeneration in the young. Spine, 24(13), 1316.
Wong, T. K., & Lee, R. Y. (2004). Effects of low back pain on the relationship between the movements of the lumbar spine and hip. Human movement science, 23(1), 21-34.
Kristjansdottir, G., & Rhee, H. (2002). Risk factors of back pain frequency in schoolchildren: a search for explanations to a public health problem. Acta Paediatrica, 91(7), 849-854.
Vikat, A., Rimpelä, M., Salminen, J. J., Rimpelä, A., Savolainen, A., & Virtanen, S. M. (2000). Neck or shoulder pain and low back pain in Finnish adolescents. Scandinavian Journal of Social Medicine, 28(3), 164-173.
Salminen, J. J., Maki, P., Oksanen, A., & Pentti, J. (1992). Spinal mobility and trunk muscle strength in 15-year-old schoolchildren with and without low-back pain. Spine, 17(4), 405-411.

Questions, comments, and criticisms are welcomed and encouraged.

Biological Risk Indicators for Recurrent Non-Specific Low Back Pain in Adolescents

Research Review: Biological Risk Indicators for Recurrent Non-Specific Low Back Pain in Adolescents

Bibliography:

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