Bilateral Correlations between Peak Ground Reaction Forces and Bone Mineral Density in Male Collegiate Runners

Abstract

Overuse injuries are prevalent in distance runners due to the repetitive nature of the sport. Some runners exhibit speed dependent asymmetries in their running mechanics, which may play into the fact that these injuries often occur unilaterality. Analyzing correlations between ground reaction forces (GRF) and bone mineral density (BMD) may help elucidate whether the risk of overuse injuries differs between legs. PURPOSE: To investigate the bilateral correlations between peak GRF at two different speeds and left and right femoral neck BMD in male, NCAA Division I distance runners. METHODS: Fifteen male collegiate runners participated in this study (Age: 20 ± 1 year; Height: 179 ± 9 cm; Weight: 70 ± 15 kg; Body Fat: 10.75 ± 4 %). Ground reaction forces (N) were collected with Noraxon SciFit (Scottsdale, AZ) instrumented treadmill as participants ran at two different speeds; threshold pace (TP: 19.3 km/hr or 5:00 min/mi) and long-slow distance pace (LSD: 13.8 km/hr or 6:58 min/mi). The femoral necks were scanned with dual-energy x-ray absorptiometry (DXA) using Norland Elite (Fort Atkinson, WI). Peak stance-phase GRF of the left and right leg were extracted from the TP and LSD condition. Femoral neck BMD (g/cm2) values for right and left leg were extracted from the DXA scans. Bivariate correlations were used to analyze the correlations between femoral neck BMD and peak GRF at the two running speeds. Separate correlation analyses were run for the left and right leg. RESULTS: During the LSD condition, peak GRF and BMD data were correlated only for the right leg (Right: r = 0.539, p = 0.03; Left: r = 0.412, p = 0.127). Similarly, peak GRF and BMD were correlated only for the right leg during the TP condition (Right: r = 0.53, p = 0.042; Left: r = 0.506, p =0.054). CONCLUSIONS: Peak stance-phase GRF of the right leg were positively correlated with BMD of the right femoral neck, regardless of running speed. The fact that significant correlations between peak GRF and BMD data were only observed on one side suggests that side-to-side differences could influence the risk of sustaining unilateral overuse injuries in runners.