Tibial bone stress injuries, pubertal stage, bone properties and muscle strength in young competitive female gymnasts - Two years follow-up.

OBJECTIVES

To examine the prevalence of young gymnasts with tibial bone-stress-injuries (BSIs) and its association with anthropometrics, pubertal-stage, bone properties, and muscle strength during two years.

STUDY

DESIGN

Follow-up.

SETTING

Gymnasium.

PARTICIPANTS

129 female competitive gymnasts (aged 11.6 ± 1.8yrs).

MAIN OUTCOME MEASURES: Gymnasts were clinically evaluated at baseline, after one-year (first follow-up) and after two-years (second follow-up) for BSIs, anthropometrics, training-volume, puberty, bone-status, and muscle-strength.

RESULTS

Prevalence of BSIs was significantly higher in pre-pubertal (64.7 %) compared to entering-puberty (30.9 %) and late-pubertal gymnasts (4.4 %) (p = 0.032). Tibial-strength and muscle-strength were significantly higher in gymnasts with no-BSIs compared with those with ≥2 episodes of BSIs (p < 0.001 and p < 0.05, respectively). Significant interactions (timeXBSIs) were found for bone-status (F(2, 254) = 4.296, p = 0.015), and for plantar-flexors and knee-extensors muscle-strength (p = 0.019 and p = 0.002, respectively). Nominal-regression showed that reduced tibial-strength, reduced plantar-flexors, pre-puberty and entering-puberty differentiated between participants with ≥2 episodes of BSIs and non-injured (p < 0.05).

CONCLUSIONS

Pre-pubertal gymnasts had the highest prevalence of clinical-BSIs compared with entering-puberty and late-pubertal gymnasts. Reduced tibial-strength, reduced muscle-strength, and being pre- or entering-puberty were parameters associated with BSIs in two or three of the assessments. Screening gymnasts from young age and implementing injury-prevention programs may reduce bone injuries.