LOW-BACK-PAIN AND ITS RELATIONSHIP TO BACK STRENGTH AND PHYSICAL-ACTIVITY IN CHILDREN

Objective. The objective of the study was to determine the occurrence of low back pain and its relationship to back strength and physical ac tivity in children. Methods and materials. The study included 53 boys and 43 girls aged 10 to 19 years from a group of 116 children who had undergone isometric strength testing 4 years previously. No interventi on was performed. Each child was asked five questions concerning low b ack pain. A questionnaire to quantify participation in athletic activi ties and manual labor was used as the basis for calculation of each ch ild's activity level. Isometric back flexor and extensor strength were measured with the same method used 4 years previously. Statistical an alyses were performed with appropriate correction for confounding fact ors. Results: The frequency of low back pain and the relationship betw een low back pain and age, between low back pain and back strength, an d between low back pain and physical activity were determined. There w as a history of low back pain in 51%, and the frequency of low back pa in in the past year was 35%. Eight percent of the children had been li mited by low back pain, and 7% had seen a doctor for the pain. The fir st incident of low back pain occurred at a mean age of 12.3 years. The frequencies of a history of low back pain and of low back pain in the past year increased significantly with age (p = 0.02 and 0.01, respec tively). Increased physical activity was significantly associated with a history of low back pain (p = 0.03), and increased back flexor stre ngth was significantly associated with a history of low back pain and of low back pain in the past year (p = 0.03 and 0.008, respectively). The rate of change in back flexor strength over 4 years had a signific antly positive association with the occurrence of low back pain in the past year (p = 0.008). Conclusions and relevance: Low back pain is co mmon in children, and, in contrast to adults, low back pain in these c hildren was more common with increased physical activity and stronger back flexors. We believe the main causes of low back pain in children are musculotendinous strains and ligamentous sprains.