, West Sussex, United Kingdom). Trec was measured using a rectal thermistor inserted 10 cm past the anal sphincter prior to beginning each experimental session (Mon-a-Therm, Covidien, Mansfield, MA, United States). Weighted mean skin temperature (Tsk) was recorded using skin thermistors (Squirrel Thermal Couples, Grant Instruments, Cambridge, United Kingdom) attached to four sites: the mid-point of the right pectoralis major (Tbreasts), midpoint of the right biceps brachii (Tarm), right rectus femoris (Tleg), and right gastrocnemius lateral head (Tlowerleg). Skin and rectal thermistors were connected to a Squirrel Data Logger (Squirrel 2020 series, Eltek, Ltd., United Kingdom) and were recorded at 30-s intervals throughout HA sessions and HTTs. HR (Polar Electro, Kempele, Finland) was also recorded throughout each session. Power output and distance cycled were recorded by the Velotron Coaching Software (Velotron CS 2008, RacerMate Inc., Seattle, WA, United States). Blood lactate measures were taken from a finger-tip blood sample and immediately analyzed using a Lactate Plus analyzer (Lactate Plus, , MA, United States). Active sweat glands were quantified using a modified-iodine paper technique with computer aided analysis (Gagnon et al., 2012). Samples were collected from the dorsal side of the thickest segment of the forearm. Thermal sensation and thermal comfort ratings were measured using 13-point and 10-point scales, respectively, which were modified from scales used by Gagge et al. (1967).
Mean Trec for the final 75 min of the session, which followed the 15-min high-intensity intervals, is represented by Trec75. Maximum Trec recorded during the session (Max Trec) was used to calculate Trec increase from rest (?Trec). Tsk was calculated as a weighted average according to Ramanathan (1964):
Estimated sweat rate relative to body surface area (SRBSA) was calculated from changes in NBM pre- to post-session with considerations of water consumed body surface area [(BSA); calculated using the formula derived by Du Bois and Du Bois, 1916] and normalized for exercise time:
A few thinking was indeed gotten having measurements of asleep blood lactate and a supplementary two opinions was in fact acquired to own blood lactate after HTTs. The outcome had been averaged in order to produce one worth for every date part (pre- and you can article-trial). Tall outliers losing outside of the physiological variety was omitted, and just this new intellectual value was used (Goodwin ainsi que al., 2007; n = 3 incidences).
Power output (watts) was recorded each second during HTTs, and an average of each minute’s power output was used to calculate area under the curve (AUC; Pruessner et al., 2003). AUC was also calculated for Trec (recorded at 30-s intervals) during HTTs. All data were analyzed using SPSS statistical software (SPSS version 24.0.0, SPSS, Chicago, IL, United States). To assess performance and physiological differences during HA days 1–4 vs . days 5–9, a mean value was calculated for each participant across the aforementioned days, and analyzed using a repeated-measures one-way analysis of variance (ANOVA). Mean performance values during HTTs (i.e., power output and speed), AUC comparisons (power output and Trec), distance cycled, and physiological measures between HTT1, HTT2, and HTT3, were also analyzed using a repeated-measures one-way ANOVA. Additionally, 1 min averages of power output were analyzed using a two-way repeated-measures ANOVA (3 HTT ? 15 time points). Normality of the data was assessed using Mauchly’s test of sphericity, and Greenhouse–Geisser corrections were applied where assumptions of sphericity were violated. When a significant main effect was found, Bonferroni-corrected post hoc comparisons were made. Main effect sizes for both one-way and two-way ANOVAs were calculated using partial eta-squared ( ? p 2 ), with ? p 2 > 0.06 representing a moderate difference and ? p 2 > 0.14 representing a large difference (Cohen, 1988). To assess ordinal data (i.e., RPE, thermal sensation and thermal comfort) differences during HA days 1–4 vs. days 5–9, and between HTT1, HTT2, and HTT3, Friedman’s test was performed with post hoc analysis by Wilcoxon sign-rank tests. Absolute data are expressed as mean ± standard deviation (SD) and mean within-subject differences are presented with 95% confidence limits (mean difference, 95% CL: lower limit, upper limit). Significance was set at p ?1 , [?1, ?10]; p = 0.03, and ?3% [?1, ?5]; p = 0.02, respectively) were also lower during HA sessions on days 5–9 as compared to HA sessions on days 1–4. These physiological changes were present in spite of a significantly higher workload (i.e., power output) on days 5–9 as compared to HA sessions on days 1–4 (?9 W, [?3, ?14], p = 0.01). Participants’ mean RPE, thermal sensation, and thermal comfort ratings across all HA sessions were not different (p > 0.05) and equalled 15 ± 2 (“Hard”), 10 ± 1 (“Hot”), and 5 ± 2 (“Uncomfortable”), respectively. There were no changes in ?Trec or sweat loss (p > 0.05). Results of HA sessions are summarized in Table 2.