Influence of Relative Adiposity on Static Back Extensor Muscle Endurance in Apparently Healthy Adults

An exploration of the relationship between back muscle endurance and familial, physical, lifestyle, and psychosocial factors in adolescents and young adults

STUDY DESIGN

Cross-sectional investigation.

OBJECTIVE

To explore the relationship between back muscle endurance (BME) and a range of familial, physical, lifestyle, and psychosocial variables in adolescents and young adults.

BACKGROUND

There is evidence that low back pain interventions which focus on improved BME are effective. However, the mechanisms associated with BME performance in adolescents and young adults are largely unclear. In particular, the potential familial relationship between parents and their children remains unexplored.

METHODS

This study utilized a subset of participants from the Joondalup Spinal Health Study cohort. One hundred nine children (47 boys, 62 girls) and 101 parents (39 fathers, 62 mothers) completed a series of physical, lifestyle, and psychosocial assessments. The univariable relationship between each covariate and BME was explored. Those found to have an association with child BME (P<.2) were included in an initial multivariable model and sequentially removed, until all remaining covariates were statistically significant (P<.05).

RESULTS

Mothers' BME performance was related to children's performance, accounting for 14.4% of the variance in the children's BME. Fathers' BME performance had a similar, albeit nonsignificant effect. Children's sitting trunk angle, pain sensitivity, percent trunk fat, waist girth, and body mass index were associated with their BME performance, accounting for between 5.2% and 20.9% of BME.

CONCLUSIONS

The final multivariable model, including mother's BME, percent trunk fat, and sitting trunk angle, explained 28% of the variance in BME performance, suggesting that for successful BME intervention a range of multidimensional variables should be considered.

The relationship between back muscle endurance and physical, lifestyle, and psychological factors in adolescents

STUDY DESIGN

Cross-sectional investigation.

BACKGROUND

There is some evidence that interventions directed to improving back muscle endurance (BME) in adolescents are effective in reducing low back pain, with anecdotal evidence of improved performance. However, the mechanisms responsible for this improvement remain unclear.

OBJECTIVE

To identify the relationship between physical, lifestyle, and psychological variables and BME in a large adolescent population, while controlling for back pain and gender.

METHODS

One thousand four-hundred thirty-five adolescents (702 females, 733 males; mean +/- SD age, 14.0 +/- 0.2 years) completed a range of physical, lifestyle, and psychological assessments. The group mean +/- SD height and body mass were 164 +/- 8 cm and 57.1 +/- 12.6 kg, respectively. Linear regression was used to investigate the univariate association between each of the physical, lifestyle, and psychological variables and BME. Backwards stepwise multivariate linear regression was used to determine statistically significant independent correlates of BME.

RESULTS

The final multivariate model explained 15.3% of the variance in BME and included at least 1 variable from the physical, lifestyle, and psychological domains. Adolescents who exercised less, watched more television, had a higher body mass index, sat in a more flexed trunk posture (more slumped), and had lower self-efficacy had lower BME.

CONCLUSIONS

All the physical and lifestyle variables linked with poorer BME performance in this investigation are indicative of reduced back muscle activation and/or deconditioning. Psychological predictors may have direct and/or indirect links with BME.