Evaluating Physical Condition In Elite Junior Weightlifters With Heart Rate And Heart Rate Variability

Abstract

Elite weightlifters train with extremely high training load during intense training periods. Since excessive training could lead to overtraining, it might be essential for weightlifters to evaluate changes in their physical condition in the course of intense training periods. Previous studies suggest that the changes in autonomic indices such as heart rate (HR) and heart rate variability (HRV) may offer a way of evaluating the changes in physical condition. It has not been well examined, however, whether measuring HR and HRV would be efficient as well for elite weightlifters to evaluate the changes in their physical condition. PURPOSE: To examine whether measuring HR and HRV would be efficient for elite weightlifters to evaluate the daily changes in the physical condition during an intense training period. METHODS: Six Japanese male junior weightlifters (18.7+0.5 yrs) participated in the study. Data were collected every morning during an 8-day weightlifting junior national team training camp. Beat-to-beat HR were recorded for five minutes under the controlled breathing of 15 breaths per minute. Frequency domain heart rate variability indices were estimated by using MemCalc software. The spectral power in the low-frequency (LF: 0.04-0.15Hz) and the high-frequency (HF: 0.15-0.40Hz) bands were calculated. In addition, normalized units (LFnu and HFnu) and the ratio of LF/HF index were obtained. The subjects were also asked to estimate subjectively perceived daily training load on a visual analog scale. RESULTS: There was a significant positive correlation between the daily changes in HR and the daily changes in training load (r=0.49, p<0.01). Moreover, significant negative correlations were observed between the daily changes in HF, HFnu and the daily changes in training load (r=-0.33, p<0.05 and r=-0.37, p<0.05, respectively). These results suggest that the daily changes in HR and HRV reflect the physiological effects of the daily training in elite weightlifters. CONCLUSIONS: Measuring autonomic indices such as HR and HRV would be an efficient tool for monitoring the day-by-day stress of training, which might lead to a practical way of evaluating the changes in physical condition in elite weightlifters.