The Effect of Ground Contact Time on VO۲max and Heart Rate Variability During Treadmill Running

This study aimed to investigate the effect of ground contact time on VO۲max and heart rate variability (HRV) during treadmill running at different speeds. Thirty male athletes (age: Yε, ± Y,) years) with at least three years of running experience participated in this quasi-experimental study with repeated measures. Participants ran on a treadmill at three speeds (^,), and km/h) with a ۱% incline. Ground contact time (GCT) was recorded using a force plate, VO۲max was measured using a metabolic gas analyzer (Bruce protocol), and HRV indices were recorded via electrocardiography. Data were analyzed using repeated-measures ANOVA, independent t-tests, and Pearson correlation coefficients. Increasing speed significantly decreased GCT (p =.۱) and increased VO۲max (p = ۱), while HRV decreased (p =.,..). GCT and VO۲max showed significant differences among all three speeds (p < ۰), but HRV only showed a significant difference between ^ and ۱ km/h (p =.,.). Athletes with higher training experience exhibited shorter GCT (p < *,*)), higher VO۲max (p < *,**\), and greater HRV (p = *,**). Significant negative correlations were observed between GCT and VO۲max (r=-,A) and HRV (r=-, ^). Reduced ground contact time is associated with improved aerobic capacity and better autonomic nervous system function. Concurrent monitoring of GCT and HRV may serve as an effective tool for evaluating training responses and preventing overtraining in endurance athletes.

کلیدواژه ها:

Ground Contact Time ، VO۲max ، HRV ، Treadmill Running ، Biomechanics