Cross-sectional geometry of weight-bearing tibia in female athletes subjected to different exercise loadings.
Level 4 - case-series / case-control
Cross-sectional comparative study
PubMed 19921084 · doi:10.1007/s00198-009-1101-0
What was done
This cross-sectional study evaluated the association between long-term sport-specific exercise loading and tibial cross-sectional geometry in 204 premenopausal female athletes across 11 different sports and 50 physically active, non-athletic referents. Athletes were categorized into five exercise loading groups: high-impact (jumping), odd-impact (ball games), repetitive low-impact (endurance running), high-magnitude (powerlifting), and repetitive non-impact (swimming). Tibial cross-sectional geometry was measured at distal and shaft sites using peripheral quantitative computed tomography (pQCT), and between-group differences were evaluated using analysis of covariance.
What was found
At the distal tibia, the high-impact, odd-impact, and repetitive low-impact groups had approximately 30% to 50% greater cortical area (CoA; p < 0.05) compared to referents. At the tibial shaft, these three impact groups exhibited approximately 15% to 20% greater total cross-sectional area (ToA; p < 0.05) and approximately 15% to 30% greater CoA (p < 0.05). In contrast, the high-magnitude (powerlifting) and repetitive non-impact (swimming) groups showed similar ToA and CoA values to the reference group at both tibial measurement sites.
Why it matters
The findings demonstrate that bone geometry adaptations in the weight-bearing tibia are specific to impact loading involving high strain rates, whereas high-magnitude static or non-impact loading did not associate with enhanced tibial cortical dimensions.
Limits
The cross-sectional design cannot establish causality or rule out self-selection bias into specific sports. The study was restricted to premenopausal female athletes, limiting generalizability to males, older populations, or postmenopausal women. Exact training volume, duration of sports participation, dietary intake, and hormonal status were not reported in the abstract.
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