Modeling Oxygen Uptake during V1 Treadmill Roller Skiing

The use of regression equations to predict oxygen uptake in relation to speed, grade, power output, and anthropometric characteristics is common in cardiac rehabilitation and athlete fitness testing. Research has suggested that sport specific testing improves the reliability of the test methodology and is appropriate for the development of effective training programs. This study focused on the development of a cross-country skiing specific predictor of maximal oxygen uptake based on treadmill speed, treadmill grade, gender, and body mass. This project simulated snow skiing on a large research treadmill using roller skis. A small sample size (N = 34) warranted the use of bootstrapping techniques and multiple regression analysis to develop a cross-country skiing specific model of oxygen uptake. The stability of each bootstrapped sample was confirmed via a cross-validation procedure. The equation of best resolve was: VO2 = -4.534 + 0.223(G) + 0.061(BM) + 0.139(TG) + 0.016(TS) in which G = Gender, BM = Body Mass, TG = Treadmill Grade, TS = Treadmill Speed. The resultant model can be used to design training programs, develop athlete fitness testing or research protocols, and to predict maximal oxygen uptake when sophisticated metabolic measurement equipment is unavailable

Analysis of a sprint ski race and associated laboratory determinants of world-class performance

This investigation was designed to analyze the time-trial (STT) in an international cross-country skiing sprint skating competition for (1) overall STT performance and relative contributions of time spent in different sections of terrain, (2) work rate and kinematics on uphill terrain, and (3) relationships to physiological and kinematic parameters while treadmill roller ski skating. Total time and times in nine different sections of terrain by 12 world-class male sprint skiers were determined, along with work rate and kinematics for one specific uphill section. In addition, peak oxygen uptake (VO2peak), gross efficiency (GE), peak speed (Vpeak), and kinematics in skating were measured. Times on the last two uphill and two final flat sections were correlated to overall STT performance (r = ~−0.80, P < 0.001). For the selected uphill section, speed was correlated to cycle length (r = −0.75, P < 0.01) and the estimated work rate was approximately 160% of peak aerobic power. VO2peak, GE, Vpeak, and peak cycle length were all correlated to STT performance (r = ~−0.85, P < 0.001). More specifically, VO2peak and GE were correlated to the last two uphill and two final flat section times, whereas Vpeak and peak cycle length were correlated to times in all uphill, flat, and curved sections except for the initial section (r = ~−0.80, P < 0.01). Performances on uphill and flat terrain in the latter part were the most significant determinants of overall STT performance. Peak oxygen uptake, efficiency, peak speed, and peak cycle length were strongly correlated to overall STT performance, as well as to performance in different sections of the race

Calculating lactate anaerobic thresholds in sports involving different endurance preparation

AbstractThe aim of this study was to establish the degree of similarity of exercise intensity values at the anaerobic threshold (AT) provided by five methods of lactate curve analysis, i.e., LTAT, LTloglog, 1 mmol AT, 4 mmol AT, and D-max. The pattern of similarities and differences was sought in athletes with varying levels of experience and sports skills, representing two disciplines with different prevailing types of power output during competition: on-road cycling (aerobic metabolism) and ice-hockey (anaerobic metabolism).All groups of athletes tested [Group 1: on-road cyclists (n = 19) at international sporting level (participants of the Olympic Games and World Championships); Group 2: on-road cyclists (n = 20) at national sporting level; Group 3: ice-hockey players (n = 24) at international sporting level (Polish National Team); and Group 4: ice-hockey players (n = 22) at international sporting level (Polish National Team U-20)] performed an incremental exercise.The greatest power values at the anaerobic threshold (PAT) were provided by the LTAT (221.93 ± 34.5 W) and 4 mmol AT (226.38 ± 32.33 W) methods, whereas the lowest were provided by the LTloglog (190.71 ± 25.92 W) method. The PAT produced by the LTloglog method was statistically significantly lower (p ≤ 0.001) than the values provided by LTAT, 4 mmol AT, and Dmax. The PAT levels were found to be statistically significantly different for power values determined using the 4 mmol AT and those produced by the 1 mmol AT (p ≤ 0.001) and D-max (p ≤ 0.01) methods. As shown by the analyses, PAT values vary in the international-level on-road cyclists depending on the method of lactate curve analysis applied

Acta kinesiologiae Universitatis Tartuensis. 5

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Relationship of the anaerobic threshold and running performance in female recreational runners

The purpose of the present study was to assess the relationship between anaerobic threshold values and performance times on the 5 km and 10 km distance races in female recreational runners. Anaerobic threshold (AT), VO2 max, and related measures were determined for 31 runners aged 18-35 who were running between 15-30 miles per week at the onset of the study. Physiological measures were determined by subjecting the runners to maximal and submaximal treadmill exercise. Determination of AT was based upon respiratory gas exchange and was defined as the departure from linearity of VEV02 without a corresponding increase in VEVO2. Mean AT-VO2 was 34.98 ml•kg•min -1 (1.978 1-min -1) while VO2 max averaged 45.42 ml•kg•min -1(2.556 1•min ). Mean percentage of AT-V02 was 78.8%. Average treadmill velocity at AT was 152.53 m/min. The correlations between VO2 max and 10 km and 5 km performances were significant (r = -.67 and -.58, respectively) while those between AT-V02 and running performances were not significant. However, when demographic characteristics of subjects were adjusted, treadmill velocity at AT and percentage of AT-V02 were the best predictors of 10 km performance. Treadmill velocity at AT alone was the best predictor of 5 km performance when the effects of physical variables were partialed out. It was concluded that additional physiological parameters should be considered when attempting to predict 5 km and 10 km performance times for female recreational runners

A comparison of isocapnic buffering phase of cross-country skiers and alpine skiers

Purpose: The purpose of this study was to compare the isocapnic buffering phase in cross-country skiers and alpine skiers during an incremental treadmill exercise test. Material: International level male junior skiers including twelve cross-country skiers and ten alpine skiers took part in the study. All participants performed an incremental treadmill exercise test to determine ventilatory threshold (VT), respiratory compensation point (RCP), and maximal oxygen uptake (VO2max). The isocapnic buffering phase was calculated as the difference in VO2 (ICBVO2) and running speed (ICBSPEED) between RCP and VT and expressed in either absolute or relative values. Results: VO2max, maximal running speed, time to exhaustion, both absolute and relative VT values and absolute RCP values were higher in the cross-country skiers than in the alpine skiers (P 0.05). Absolute ICBVO2 and ICBSPEED showed similar values in both group (p > 0.05), whereas relative ICBVO2 and ICBSPEED were found to be significantly higher in alpine skiers than in cross-country skiers (P < 0.05). Maximal respiratory exchange ratio was higher in alpine skiers than in cross-country skiers. Conclusions: The current findings suggest that anaerobic training may induces specific metabolic adaptations leading to increase in buffering capacity which may be a contributing factor to continue to exercise for relatively longer periods of time above the VT. Longer ICB phase in the anaerobic-trained athletes may an important factor in relation to the enhance high-intensity exercise tolerance

A COMPARISON OF METHODS FOR CALCULATING LACTATE ANAEROBIC THRESHOLDS IN JUDO AND MIXED MARTIAL ARTS ATHLETES

The study aimed to determine the differences between exercise intensities at the anaerobic threshold values (VAT) calculated with methods of lactate curve analysis such as LTvisual, LTloglog, LT4.0, LTΔ1, and LTD-max, and to build regression equations that allow athletic training specialists to compare VAT values obtained from LTvisual, LTloglog, LTΔ1, LTD-max with that calculated with LT4.0. The sample analysed during the study consisted of 19 judoka and 22 MMA practitioners in a preparation period for competition. Each of the two disciplines has its own hierarchy of VAT values. The analysis aimed to determine the effect of the athletic discipline factor and of the method factor on VAT values. Results: The coefficient of variation (CV) values obtained indicate that the effective exercise intensities have bigger variation in judoka aerobic endurance training. VAT values assessed for judoka using different methods for analysing the blood lactate concentration curve are more consistent than in MMA competitors. Conclusions: Judo and MMA competitors have their specific hierarchies of running velocities at the anaerobic threshold, with both the athletic discipline factor and the method factor having an interaction effect on the VAT level. VAT levels assessed from the different methods used to analyse the blood lactate concentration curve are more consistent (ANOM) in judoka than in MMA practitioners

Acta kinesiologiae Universitatis Tartuensis. 13

http://www.ester.ee/record=b1227224*es

Acta kinesiologiae Universitatis Tartuensis. 17

http://www.ester.ee/record=b1227224*es