Comparison of Morning Heart Rate Variability at the Beginning and End of a Competition Season in Elite Speed Skaters.

The aim of this study was to clarify whether the physiological fatigue status of elite speed skaters is influenced by the approximately five-month international competition season by comparing morning heart rate variability (HRV) at the beginning of the competition season (Japan Single Distances Championships: JSDC) with that at the end of the competition season (World Single Distances Championships: WSDC). Five international-class speed skaters participated in the study. HRV indices and subjective fatigue were measured each morning of the four days prior to the first races of the JSDC and WSDC in the 2007/2008 season. The parasympathetic HRV indices: root mean square of the successive R-R interval differences (RMSSD) (JSDC, 61.0 ms; WSDC, 42.1 ms; p < 0.05), high-frequency component power (HF) (JSDC, 1393 ms2; WSDC, 443 ms2; p < 0.05), and normalized unit of HF (HFnu) (JSDC, 53.2%; WSDC, 25.5%; p < 0.05) were lower for the WSDC than for the JSDC. The decrease in these indices may reflect the skaters' accumulated fatigue during the course of the competition season. Morning measurements of HRV may thus be an efficient way for elite speed skaters and coaches to objectively monitor physiological fatigue throughout the competition season.

Correlation between degree of hallux valgus and kinematics in classical ballet: A pilot study.

Hallux valgus is a serious medical concern for classical ballet dancers. Although it is well-known that progression of hallux valgus is related to inappropriate movement techniques in classical ballet, the kinematic relationship between the degree of hallux valgus and ballet techniques has not been substantiated. To develop proper training methods that prevent progression of hallux valgus, this study aimed to investigate the relationship between the degree of hallux valgus and movement techniques in classical ballet. Seventeen female classical ballet dancers at the advanced college-level participated in this study. Kinematic analysis of standing and plié in the first position was conducted via video capture technique. The Pearson product-moment correlation analysis was performed to examine the degree of hallux valgus and the following three kinematic variables: (1) the extent to which turnout is forced by other joints in the lower extremity than the hip joint, (2) the direction difference between the knee and toe in the transverse plane, and (3) the pelvis obliquity angle. Among these kinematic variables, we found a significant correlation between the hallux valgus angle and the pelvis obliquity angle during plié (P = .045). The greater the hallux valgus angle, the greater the retroversion of the pelvis, a result which was contrary to our prediction. We present the first evidence that the degree of hallux valgus correlates with kinematics in a very basic technique of classical ballet.

Salivary secretory immunoglobulin a response of elite speed skaters during a competition period.

We aimed to determine the responses of salivary secretory immunoglobulin A (SIgA) and the incidence of upper respiratory tract infections (URTI) symptoms among elite speed skaters during an actual competition period. The subjects were 8 international-class elite speed skaters. Saliva samples were obtained 3, 2, and 1 days before the race, the day of the race, and 1 day after the race. Salivary secretory immunoglobulin A concentration was measured by enzyme immunoassay, and SIgA secretion rate was calculated. A visual analogue scale was used to subjectively assess fatigue and tension. Daily URTI symptoms were recorded by using a questionnaire. There was no statistically significant difference in the saliva flow rate (p = 0.69), SIgA concentration (p = 0.07), and subjective fatigue (p = 0.07) during the competition period. The SIgA secretion rate recorded for the day of the race was significantly high compared with that of 3 and 2 days before and 1 day after the race (p < 0.05). The subjective tension recorded on the race day was significantly high compared with that for 3, 2, and 1 days before the race (p < 0.05). Two subjects exhibited URTI symptoms after the race. These findings suggest that salivary SIgA in elite speed skaters increased after a tapering period and that an actual high-intensity speed skating race decreased salivary SIgA in elite speed skaters. These data also suggest that the incidence of URTI symptoms might be related to the SIgA level. Coaches may need to take precautions after competitions to minimize their athletes' contact with cold viruses and adjust training load for a few days after competition to improve the decreased mucosal immune function.