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  • Author: Juan M. Murias x
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Erin Calaine Inglis, Danilo Iannetta, Louis Passfield and Juan M. Murias

Purpose: To (1) compare the power output (PO) for both the 20-minute functional threshold power (FTP20) field test and the calculated 95% (FTP95%) with PO at maximal lactate steady state (MLSS) and (2) evaluate the sensitivity of FTP95% and MLSS to training-induced changes. Methods: Eighteen participants (12 males: 37 [6] y and 6 females: 28 [6] y) performed a ramp-incremental cycling test to exhaustion, 2 to 3 constant-load MLSS trials, and an FTP20 test. A total of 10 participants returned to repeat the test series after 7 months of training. Results: The PO at FTP20 and FTP95% was greater than that at MLSS (P = .00), with the PO at MLSS representing 88.5% (4.8%) and 93.1% (5.1%) of FTP and FTP95%, respectively. MLSS was greater at POST compared with PRE training (12 [8] W) (P = .002). No increase was observed in mean PO at FTP20 and FTP95% (P = .75). Conclusions: The results indicate that the PO at FTP95% is different to MLSS, and that changes in the PO at MLSS after training were not reflected by FTP95%. Even when using an adjusted percentage (ie, 88% rather than 95% of FTP20), the large variability in the data is such that it would not be advisable to use this as a representation of MLSS.

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Tatiane Piucco, Rogério Soares, Fernando Diefenthaeler, Guillaume Y. Millet and Juan M. Murias

Purpose: To compare the oxygen-uptake (V˙O2) kinetics during skating on a treadmill and skating on a slide board and to discuss potential mechanisms that might control the V˙O2 kinetics responses during skating. Methods: Breath-by-breath pulmonary V˙O2 and near-infrared spectroscopy–derived muscle deoxygenated hemoglobin and myoglobin ([HHbMb]) were monitored continuously in 12 well-trained, young, long-track speed skaters. On-transient V˙O2 and [HHbMb] responses to skating on a treadmill and skating on a slide board at 80% of the estimated gas exchange threshold were fitted as monoexponential function. The signals were time-aligned, and the individual [HHbMb]-to-V˙O2 ratio was calculated as the average value from 20 to 120 s after exercise starts. Results: The time constants for the adjustment of phase II V˙O2V˙O2) and [HHbMb] (τ [HHbMb]) were low and similar between slide board and treadmill skating (18.1 [3.4] vs 18.9 [3.6] for τ V˙O2 and 12.6 [4.0] vs 12.4 [4.0] s for τ [HHbMb]). The [HHbMb]:V˙O2 ratio was not different from 1.0 (P > .05) in both conditions. Conclusions: The fast V˙O2 kinetics during skating suggest that chronic adaptation to skating might overcome any possible restriction in leg blood flow during low-intensity exercise. The V˙O2 ratio values also suggest a good matching of O2 delivery to O2 utilization in trained speed skaters. The similar τ V˙O2 and τ [HHbMb] values between slide board and treadmill further reinforce the validity of using a slide board for skating testing and training purposes.

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Erin Calaine Inglis, Danilo Iannetta, Daniel A. Keir and Juan M. Murias

Purpose: To evaluate whether the coherence in the oxygen uptake (V˙O2) associated with the respiratory compensation point (RCP), near-infrared spectroscopy-derived muscle deoxyhemoglobin ([HHb]) break point ([HHb]BP), and maximal lactate steady state (MLSS) would persist at the midpoint and endpoint of a 7-month training and racing season. Methods: Eight amateur male cyclists were tested in 3 separate phases over the course of a cycling season (PRE, MID, and POST). Testing at each phase included a ramp-incremental test to exhaustion to determine RCP and [HHb]BP. The PRE and POST phases also included constant power output rides to determine MLSS. Results: Compared with PRE, V˙O2 at both RCP and [HHb]BP was greater at MID (delta: RCP 0.23 [0.14] L·min−1, [HHb]BP 0.33 [0.17] L·min−1) and POST (delta: RCP 0.21 [0.12], [HHb]BP 0.30 [0.14] L·min−1) (P < .05). V˙O2 at MLSS also increased from PRE to POST (delta: 0.17 [12] L·min−1) (P < .05). V˙O2 was not different at RCP, [HHb]BP, and MLSS at PRE (3.74 [0.34], 3.64 [0.40], 3.78 [0.23] L·min−1) or POST (3.96 [0.25], 3.95 [0.32], 3.94 [0.18] L·min−1) respectively, and RCP (3.98 [0.33] L·min−1) and [HHb]BP (3.97 [0.34] L·min−1) were not different at MID (P > .05). PRE–MID and PRE–POST changes in V˙O2 associated with RCP, [HHb]BP, and MLSS were strongly correlated (range: r = .85–.90) and demonstrated low mean bias (range = −.09 to .12 L·min−1). Conclusions: At all measured time points, V˙O2 at RCP, [HHb]BP, and MLSS were not different. Irrespective of phase comparison, direction, or magnitude of V˙O2 changes, intraindividual changes between each index were strongly related, indicating that interindividual differences were reflected in the group mean response and that their interrelationships are beyond coincidental.

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Tatiane Piucco, Fernando Diefenthaeler, Rogério Soares, Juan M. Murias and Guillaume Y. Millet

Purpose: To investigate the criterion validity of a maximal incremental skating test performed on a slide board (SB). Methods: Twelve subelite speed skaters performed a maximal skating test on a treadmill and on a SB. Gas exchange threshold (GET), respiratory compensation point (RCP), and maximal variables were determined. Results: Oxygen uptake (V˙O2) (31.0 ± 3.2 and 31.4 ± 4.1 mL·min−1·kg−1), percentage of maximal V˙O2 (V˙O2max) (66.3 ± 4 and 67.7 ± 7.1%), HR (153 ± 14 and 150 ±12 bpm), and ventilation (59.8 ± 11.8 and 57.0 ± 10.7 L·min−1) at GET, and V˙O2 (42.5 ± 4.4 and 42.9 ± 4.8 mL·min−1·kg−1), percentage of V˙O2max (91.1 ± 3.3 and 92.4 ± 2.1%), heart rate (HR) (178 ± 9 and 178 ± 6 bpm), and ventilation (96.5 ± 19.2 and 92.1 ± 12.7 L·min−1) at RCP were not different between skating on a treadmill and on a SB. V˙O2max (46.7 ± 4.4 vs 46.4 ±6.1 mL·min−1·kg−1) and maximal HR (195 ± 6 vs 196 ± 10 bpm) were not significantly different and correlated (r = .80 and r = .87, respectively; P < .05) between the treadmill and SB. V˙O2 at GET, RCP, and V˙O2max obtained on a SB were correlated (r > .8) with athletes’ best times on 1500 m. Conclusions: The incremental skating test on a SB was capable to distinguish maximal (V˙O2 and HR) and submaximal (V˙O2, % V˙O2max, HR, and ventilation) parameters known to determine endurance performance. Therefore, the SB test can be considered as a specific and practical alternative to evaluate speed skaters.