Running gait biomechanics associated with hamstring and quadriceps strength profiles.

OBJECTIVE

To evaluate the relationships between quadriceps and hamstring strength profiles and running gait kinetics in healthy adult athletes.

DESIGN

Cross-sectional.

SETTING

Hospital-affiliated injury prevention clinic.

PARTICIPANTS

554 healthy adult runners (355 F, 199 M).

MAIN OUTCOME MEASURES: Mass-normalized quadriceps and hamstring strength were obtained using hand-held dynamometry. Cadence, stride length, %stance, and body weight (BW) normalized peak vertical ground reaction force (vGRF) were obtained using an instrumented treadmill. Linear regression analyses were used to assess the relationships between mass-normalized hamstring and quadriceps strength and running biomechanics. Logistic regression analyses were used to assess relationships between hamstring:quadriceps (H:Q) symmetry profiles (≥0.5, <0.5) and running biomechanics.

RESULTS

Quadriceps strength was directly associated with cadence (p < 0.001) and stride lengths (p = 0.01), and inversely associated with %stance phase (p < 0.001) and vGRF (p < 0.001). Hamstring strength was directly associated with higher cadence (p = 0.003) and height-normalized stride length (p < 0.001), yet inversely associated with %stance phase (p < 0.001) and BW-normalized peak vGRF (p < 0.001). More symmetric H:Q profiles were associated with longer height-normalized stride lengths (p = 0.03).

CONCLUSIONS

Quadriceps and hamstring strength profiles were weakly inversely associated with vGRF and percentage of the gait cycle in stance phase among healthy adult runners.