Davor Šentija

STRONG RELATIONSHIP BETWEEN HEART RATE DEFLECTION POINT AND VENTILATORY THRESHOLD IN TRAINED ROWERS

Mikulic, P, Vucetic, V, and Sentija, D. Strong relationship between heart rate deflection point and ventilatory threshold in trained rowers. J Strength Cond Res 25(2): 360-366, 2011-The purpose of this study was to assess the relationship between heart rate deflection point (HRDP) and ventilatory threshold (VT) to the physiological and performance variables in a relatively large group of trained men rowers. We proposed the hypothesis that physiological and performance variables corresponding to HRDP are not significantly different from corresponding variables at VT, which would justify the use of HRDP as a simple, affordable, and noninvasive method of anaerobic threshold assessment in trained rowers. Eighty-nine trained men rowers (mean ± SD: age 21.2 ± 4.1 years; stature 1.89 ± 0.06 m; body mass 89.2 ± 8.4 kg; &OV0312;o2max [maximum oxygen uptake] 5.39 ± 0.62 L/min−1) completed an incremental rowing ergometer exercise test to exhaustion. Three independent, experienced observers determined both HRDP and VT. HRDP was determined by visual and computer-aided regression analyses and was evident in all rowers. The main findings include (a) there is a strong relationship among all observed physiological and performance variables corresponding to HRHRDP and HRVT (r = 0.79-0.96; p < 0.001) and (b) power output, oxygen uptake, ventilation, tidal volume and breathing rate corresponding to HRHRDP and HRVT were not significantly different (p ≥ 0.011), whereas HRHRDP was slightly but significantly higher than HRVT (174.5 vs. 172.8 beats·min−1; p = 0.003). The standard error of the estimate in predicting the HRVT based on HRHRDP was 5.1 beats·min−1. The subsequent data suggest that, in general, trained rowers may be able to periodically assess their aerobic endurance and evaluate the effects of training programs using the HRDP method.

Anthropometric characteristics and gait transition speed in human locomotion.

The purpose of this study was to investigate the relationship between anthropometric parameters and the preferred transition speed (PTS) in human locomotion, in both genders. Previous studies exploring body measures as possible determinants of the PTS were biased toward longitudinal body dimensions, while the relationship between the PTS and transverse body dimensions has so far not been examined. Longitudinal and transverse anthropometric parameters were measured in 48 physical education students (21 males, 27 females), and an exercise test was performed for determination of the PTS. The relationship between the PTS and the anthropometric variables was determined using Pearson product-moment correlations and stepwise multiple regression analysis. Weak to moderate correlations between several body size and body shape variables and the PTS were found. In males, significant negative correlations (p<.05) between transverse body dimensions scaled to body height (calf girth, shoulder, bicristal and bitrochanteric diameters) and the PTS were found (r=-.51 to -.63). In females, calf girth and thigh girth scaled to height were significantly negatively correlated with the PTS (r=-.61 and -.42, respectively; p<.05). The results of the study suggest that gait transition speed in humans is related to both transverse and longitudinal body dimensions, and that sexual dimorphism in body size and shape should be taken into consideration for a proper interpretation of the PTS.

The Relationship Between Gait Transition Speed and the Aerobic Thresholds for Walking and Running

We studied the relationship between the speed at the gas exchange thresholds for walking and running and the preferred gait transition speed (PTS), and the correspondence of PTS and energetically optimal transition speed (EOTS). Twenty-two men (age: 21.4+/-2.4 years, mass: 78.1+/-8.2 kg) performed four tests during which we determined VO (2max), walking/running gas exchange thresholds, walk-to-run/run-to-walk PTS, and EOTS. There were no significant differences ( P>0.05) between PTS, and the speed at the aerobic threshold for walking (AeT (w)) and running (AeT (r)). Both walk-to-run and run-to-walk PTS significantly correlated to AeT (r) (r=0.82 and 0.79; P<0.01) but not to AeT (w) (r=-0.03 and 0.06; P>0.05). Finally, EOTS and the corresponding VO (2) were significantly higher ( P<0.05) than the speed and VO (2) at PTS. Our results indicate that running rather than walking dynamics determines gait transitions in men.