Search Results (3)

Background: The purpose of this study is to ascertain the reliability of two 15-s sprint cycling tests in men and women to estimate the maximum lactate accumulation rate (VLamax). Methods: Eighteen men and twelve women completed two sprint sessions over 1 week. A 10 min warm-up preceded the obtaining of a 3 µL blood lactate (BLC) sample, after which a 15 s sprint was completed; cyclists then rested passively while multiple lactate samples were taken until the levels peaked. Trial differences and reliability across trials were analyzed using a paired-sample t-test, Pearson’s correlation, Intraclass correlation (ICC), and Bland–Altman analysis with α = 0.05 for all tests; data are reported as mean ± sd. Results: Power (W) was similar across trials (773.0 ± 143.5 vs. 758.2 ± 127.4; p = 0.333) and the coefficient of variation (CV) of 4.7%. VLamax (mM·L⁻¹·s⁻¹) was similar (0.673 ± 0.024 vs. 0.635 ± 0.237; p = 0.280), but only moderately reliable across trials with CV, ICC, and R values of 18.6%, 0.661, and 0.67, respectively. Pre-BLC and peak BLC CV were 45.6 and 23.3%, respectively. Conclusions: A 15 s VLamax cycling sprint is moderately reliable, possibly affected both by the lactate measurement and other variables used in the calculation. More research may offer ways to improve reliability. Full article

We examined the blood lactate response, in terms of the maximal post-exercise concentration (La_max), time to reach La_max, and maximal lactate accumulation rate (VLa_max), to swimming sprints of 25, 35, and 50 m. A total of 14 highly trained and elite swimmers (8 male and 6 female), aged 14–32, completed the 3 sprints in their specialization stroke with 30 min of passive rest in between. The blood lactate was measured right before and continually (every minute) after each sprint to detect the La_max. The VLa_max, a potential index of anaerobic lactic power, was calculated. The blood lactate concentration, swimming speed, and VLa_max differed between the sprints (p < 0.001). The La_max was highest after 50 m (13.8 ± 2.6 mmol·L^–1, mean ± SD throughout), while the swimming speed and VLa_max were highest at 25 m (2.16 ± 0.25 m·s^–1 and 0.75 ± 0.18 mmol·L^–1·s^–1). The lactate peaked approximately 2 min after all the sprints. The VLa_max in each sprint correlated positively with the speed and with each other. In conclusion, the correlation of the swimming speed with the VLa_max suggests that the VLa_max is an index of anaerobic lactic power and that it is possible to improve performance by augmenting the VLa_max through appropriate training. To accurately measure the La_max and, hence, the VLa_max, we recommend starting blood sampling one minute after exercise. Full article

Background and Objectives: This study aimed to compare the calculated running velocity at the anaerobic lactate threshold (cLT_An), determined by a mathematical model for metabolic simulation, with two established threshold concepts (onset of blood lactate accumulation (OBLA; 4 mmol∙L⁻¹) and modified maximal deviation method (mDmax)). Additionally, all threshold concepts were correlated with performance in different endurance running events. Materials and Methods: Ten sub-elite runners performed a 30 s sprint test on a cycle ergometer adjusted to an isokinetic mode set to a cadence of 120 rpm to determine maximal lactate production rate (VLa_max), and a graded exercise test on a treadmill to determine maximal oxygen uptake (VO_2max). Running velocities at OBLA, mDmax, and cLT_An were then compared with each other, and further correlated with running performance over various distances (3000 m, 5000 m, and 10,000 m). Results: The mean difference in cLT_An was −0.13 ± 0.43 m∙s⁻¹ and −0.32 ± 0.39 m∙s⁻¹ compared to mDmax (p = 0.49) and OBLA (p < 0.01), respectively. cLT_An indicated moderate to good concordance with the established threshold concepts (mDmax: ICC = 0.87, OBLA: ICC = 0.74). In comparison with other threshold concepts, cLT_An exhibited comparable correlations with the assessed running performances (cLT_An: r = 0.61–0.76, mDmax: r = 0.69–0.79, OBLA: r = 0.56–0.69). Conclusion: Our data show that cLT_An can be applied for determining endurance performance during running. Due to the consideration of individual physiological profiles, cLT_An offers a physiologically justified approach to assess an athlete’s endurance performance. Full article