Search Results

Purpose : This study compared the effects of individualizing supramaximal interval rowing interventions using anaerobic power reserve (APR [high-intensity interval training (HIIT) prescribed according to individual APR (HIIT_APR)]) and power associated with maximal oxygen uptake ( ${\mathrm{W}\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ [HIIT prescribed based on the individual ${\mathrm{W}\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ (HIIT_W)]) on the homogeneity of physiological and performance adaptations. Methods : Twenty-four well-trained rowers (age 24.8 [4.3] y, stature 182.5 [3] cm, body mass 86.1 [4.3]) were randomized into interventions consisting of 4 × 30-second intervals at 130%APR ( ${\mathrm{W}\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ + 0.3 × maximal sprint power) with weekly progression by increasing the number of repetitions per set (5, 6, 7, 8, 9, and 10, from first to sixth session) and the same sets and repetitions with the intensity described as 130% ${\mathrm{W}\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ . The work-to-recovery ratio was 1:1 for repetitions and 3 minutes between sets. Responses of aerobic fitness indices, power output, cardiac hemodynamics, locomotor abilities, and time-trial performance were examined. Results : Both HIIT_APR and HIIT_W interventions significantly improved ${\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ , lactate threshold, cardiac hemodynamics, and 2000-m performance, with no between-groups difference in changes over time. However, HIIT_APR resulted in a lower interindividual variability in adaptations in ${\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ and related physiological parameters, but this is not the case for athletic performance, which can depend on a multitude of factors beyond physiological parameters. Conclusions : Results demonstrated that expressing supramaximal interval intensity as a proportion of APR facilitates imposing the same degrees of homeostatic stress and leads to more homogeneous physiological adaptations in maximal variables when compared to prescribing a supramaximal HIIT intervention using ${\mathrm{W}\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ . However, lower interindividual variability would be seen in submaximal variables if HIIT interventions were prescribed using ${\mathrm{W}\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ .

Purpose: This study examined the underlying mechanisms of postactivation potentiation and the time course of muscular- and neural-related variables. Methods: Fourteen trained males executed 4 sets of six 6-second maximum isometric conditioning plantar flexions, with 15 seconds and 2 minutes of interval between the contractions and sets, respectively. Peak twitch torque (TT), rate of torque development, time to peak torque, half relaxation time, and the neural-related variables of H-reflex and electromyogram, normalized to the maximum M-wave (H/M and RMS/M, respectively), were evaluated, as well as the level of the voluntary activation, assessed by the twitch interpolation technique. All neural-related variables were analyzed for the trial within each set when TT was maximal and for the trial within each set when the neural-related variable itself was maximal. Results: Compared with the baseline measures, TT and rate of torque development significantly increased in all sets (P < .001), whereas time to peak torque and half relaxation time significantly decreased in sets 1 to 4 and 2 to 4, respectively (P < .001). However, H/M and the RMS/M did not change for the repetition of each set for which the TT was maximal (P > .05). Interestingly, the within-set maximum H/M ratio of the lateral gastrocnemius muscle revealed a significant increase in all sets (P < .05), compared with the baseline measures. Conclusion: One set of 4 contractions with 6-second duration is sufficient to cause postactivation potentiation for most participants, whereas peak TT augmentation does not coincide with changes in the examined neural-related variables. Further experiments should consider the time lag on their maximal values and their inherent between-participants variability.

Purpose : We compared the adaptive responses to supramaximal high-intensity interval training (HIIT) individualized according to anaerobic speed reserve (ASR), the 30-15 Intermittent Fitness Test (V _IFT), and velocity associated with maximum oxygen uptake (MAS) to determine which approach facilitates more identical adaptations across athletes with different profiles. Methods : Thirty national-level basketball players (age = 28.4 [5] y; body mass = 88.9 [6.3] kg; height = 190 [4.8] cm) were randomly assigned to 3 training groups performing 2 sets of 4, 6, 8, 6, 8, and 10-minute runs (from first to sixth week, respectively), consisting of 15-second running at Δ%20ASR (MAS + 0.2 × ASR), 95%V _IFT, and 120%MAS, with 15 seconds recovery between efforts and a 3-minute relief between sets. Results : All 3 interval interventions significantly (P < .05) enhanced maximum oxygen uptake ( ${\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ ), oxygen pulse ( ${\dot{\mathrm{V}}\mathrm{O}}_2/\mathrm{HR}$ ), first and second ventilatory threshold (VT₁ and VT₂), cardiac output ( ${\dot{Q}}_{\max }$ ), stroke volume, peak and average power output, testosterone levels, and testosterone-to-cortisol ratio following the training period. Different values of interindividual variability (coefficient of variation) for the percentage changes of the measured variables were observed in response to HIIT_ASR, HIITv _IFT, and HIIT_MAS for ${\dot{\mathrm{V}}\mathrm{O}}_2\text{max}$ (8.7%, 18.8%, 34.6%, respectively), ${\dot{\mathrm{V}}\mathrm{O}}_2/\mathrm{HR}$ (9.5%, 15.0%, 28.6%), VT₁ (9.6%, 19.6%, 34.6%), VT₂ (21.8%, 32.4%, 56.7%), ${\dot{Q}}_{\max }$ (8.2%, 16.9%, 28.8%), stroke volume (7.9%, 15.2%, 23.5%), peak power output (20%, 22%, 37.3%), average power output (21.1%, 21.3%, 32.5%), testosterone (52.9%, 61.6%, 59.9%), and testosterone-to-cortisol ratio (55.1%, 59.5%, 57.8%). Conclusions : Supramaximal HIIT performed at Δ%20ASR resulted in more uniform physiological adaptations than HIIT interventions prescribed using V _IFT or MAS. Although hormonal changes do not follow this approach, all the approaches induced an anabolic effect.

Purpose: To investigate whether sleeping activity, hormonal responses, and wellness are altered in elite water polo players during their preparation toward the Tokyo Olympics. Methods: Eight elite-level water polo players participated in 3 consecutive training phases: (1) before the commencement of a residential-based conditioning camp (PRE-CAMP; 3 d), (2) residential-based conditioning camp (5 d), and (3) a congested period of training and competition (POST-CAMP; 8 d). Nocturnal sleep was monitored for 14 consecutive days in PRE-CAMP (2 d), CAMP (5 d), and POST-CAMP (7 d). Postawakening salivary cortisol, immunoglobulin-A, and subjective wellness were measured during PRE-CAMP, CAMP, and POST-CAMP, and internal training/match load (ITL) was calculated daily. The averaged values for dependent variables were compared among training phases and analyzed using linear mixed models. Results: At CAMP compared with PRE-CAMP, ITL was higher (P < .01), and sleep onset and offset were earlier (P < .01). At this period, sleep interruptions and salivary cortisol were higher (P < .01, d = 1.6, d = 1.9, respectively), and subjective wellness was worsened (P < .01, d = 1.3). At POST-CAMP, the reduction of workload was followed by increased sleep efficiency, reduced sleep interruptions, and moderately affected salivary cortisol, yet overall wellness remained unaltered. In POST-CAMP, 2 of the players demonstrated severe symptoms of illness. Conclusions: At the highest level of the sport and prior to the Olympics, large increments in workload during a training camp induced meaningful sleep interruptions and salivary cortisol increases, both of which were reversed at POST-CAMP. We suggest that the increased workload alongside the inadequate recovery affects sleep patterns and may increase the risk of infection.