High Incidence Of Lumbar Intervertebral Disk And A Possible Risk Factor For Collegiate Weightlifters

Abstract

Weightlifters experiences high mechanical stresses in their lumbar region. The intervertebral disks act as shock absorbers between each of the vertebrae in the spinal column. The disks of weightlifters may be injured by repetitive overload during weightlifting maneuvers. Previous studies have shown that excessive trunk rotation is a major risk factor for lumbar intervertebral disk degeneration (LIDD) in athletes. Although trunk rotation is not included in most weightlifting maneuvers, we hypothesized that there would be a high incidence of LIDD in collegiate weightlifters. PURPOSE: The purpose of this study was to examine the prevalence of LIDD in collegiate weightlifters. We also investigated possible risk factors for LIDD, except for excessive trunk rotation. METHODS: Forty Japanese collegiate weightlifters (25 men and 15 women; age, 19.6±1.1years; starting age, 15.1±0.9years; height, 164.7±8.0cm; weight, 71.9±14.kg). LIDD were evaluated using T2-weighted magnetic resonance images. Pfirrmann’s classification was used to define LIDD and classify the subjects into either the LIDD group or the non-LIDD group. We also investigated physical characteristics such as body composition (height, weight, muscle mass, fat mass), joint range of motion (thoracic, lumbar, and hip), and lumbosacral alignment (lumbar angle, sacral angle, and lumbosacral angle). Student’s t-test and logistic regression were used for statistical analyses. RESULTS: The prevalence of LIDD among weightlifters was 55.0%(22/40). Weight(77.3±16.40 vs. 65.7±10.24, p=0.02), fat mass(18.5±8.07 vs. 12.5±4.15, p=0.07), and body mass index(27.7±4.78 vs. 24.71±2.10, p=0.02) in the LIDD group were significantly higher than those in the non-LIDD group. Hip flexion angle (left: 121.5±10.10 vs. 126.9±6.15, p=0.05; right: 121.9±8.00 vs.127.9±7.06, p=0.04) and lumbar angle(18.3±6.04 vs. 24.2±4.65, p=0.01) were lower in the LIDD group compared to the non-LIDD group. By using logistic regression analysis including sex differences, lumbar angle was found to be a significant independent variable for LIDD (odds ratio, 1.34; 95%confidence interval 1.08-1.67, p=0.01). CONCLUSION: A high incidence of LIDD was observed in Japanese collegiate weightlifters. Lumbar angle is a possible risk factor.