The Association Between Hip Flexibility and Low Back Pain in Ice Hockey Players.

BACKGROUND

Hip flexor tightness is common in ice hockey players because of postural demands. It remains unknown whether hip tightness plays a role in the occurrence of low back pain (LBP).

HYPOTHESIS: It was hypothesized that ice hockey players with hip flexor tightness would be at increased risk of developing LBP.

STUDY

DESIGN

Cohort study; Level of evidence, 2.

METHODS

Preseason hip flexor tightness was measured annually for 4 seasons in a boy's high school team, a college men's team, and a college women's team providing a total of 289 player-seasons. A digital level was placed on the anterior thigh during the Thomas test. "Tight" was defined as a Thomas test >5° above horizontal with the remaining players defined as normal. Game and practice injuries with associated time loss and diagnosis were recorded. LBP was defined as an injury in the lumbar region requiring the player to miss ≥1 game or >2 practices. Prevalence and incidence of LBP were compared between players with tight versus normal hip flexor flexibility, and relative risks were computed. Additionally, hip flexion abduction and adduction strength was assessed with a handheld dynamometer. Incidence and prevalence of LBP was compared between weak, average, and strong players within each team.

RESULTS

There were 33 cases of LBP resulting in 97 missed games and 377 missed practices. The incidence of LBP was 1.02/1000 athlete-exposures (95% CI 0.72-1.43). Of 172 players with hip flexor tightness, 27 (15.7%) developed LBP compared with 6 of 117 (5.1%) with normal flexibility (P = .006). LBP incidence was higher for players with tight (1.42; 95% CI, 0.98-2.06) versus normal (0.55; 95% CI, 0.21-0.98) hip flexor flexibility (relative risk, 3.17; 95% CI, 1.31-7.67; P = .007). Players with hip flexor tightness missed 85 games and 318 practices because of LBP compared with 12 games and 59 practices for players with normal hip flexor flexibility (P < .001). LBP incidence was not different between teams (P = .91). Incidence of LBP was not different between players weak, average, or strong in hip flexion (P = .53), abduction (P = .48) or adduction (P = .35).

CONCLUSION

Hip flexor tightness was associated with increased risk of LBP. Hip flexor stretching and postural training is indicated for players with hip flexor tightness.