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Technique-specific high-intensity interval training (HIIT TS ) has been proven to be an effective method to enhance the sport-specific bio-motor abilities of taekwondo athletes. However, studies regarding its effects on comprehensive measures of cardiorespiratory fitness are limited. Furthermore, there is a lack of clarity regarding the extent of individual adaptations to this method compared to HIIT in the form of repeated sprints (HIIT RS ). This study compared the individual adaptations to HIIT RS and HIIT TS on cardiorespiratory fitness and anaerobic power in trained taekwondo athletes (age = 19.8 ± 1.3 years; body mass = 75.4 ± 9.1 kg; height = 1.73 ± 0.0 .m). All participants completed three sessions per week of a 60-minute regular taekwondo training. Following the 60-minute training, participants completed 3 sets of 10 × 4 s all-out HIIT RS or same sets of repeated kicks with both legs (HIIT TS ) over a 6-week training period. In both groups, rest intervals were set at 15 seconds between efforts and one minute between sets. Before and after the training period, participants underwent a series of lab- and field-based tests to evaluate cardiorespiratory fitness and bio-motor abilities. Both interventions resulted in significant improvements in maximum oxygen uptake (V̇O 2max ), O 2 pulse (V̇O 2 /HR), first ventilatory threshold (VT 1 ), second ventilatory threshold (VT 2 ), cardiac output (Q̇ max ), stroke volume (SV), peak power output (PPO), average power output (APO), squat jump (SJ), and countermovement jump (CMJ). However, linear speed (20-m speed time) and taekwondo-specific agility test (TSAT) only responded to HIIT RS . HIIT RS resulted in greater changes in V̇O 2max , V̇O 2 /HR, VT 2 , and Q̇ max , and higher percentage of responders in measured parameters than HIIT TS . In addition, HIIT RS elicited lower inter-individual variability (CV) in percent changes from pre- to post-training in all measured variables. These results suggest that incorporating 3 sessions per week of HIIT RS into regular taekwondo training results in significantly greater and more homogenized adaptations in cardiorespiratory fitness and bio-motor abilities than HIIT TS among trained taekwondo athletes., (© Journal of Sports Science and Medicine.)

Purpose: This study aimed to examine the impact of different rest periods between short sprint interval training (SSIT) trials on the physiological and performance adaptations of female volleyball players., Methods: Twenty-four trained college athletes volunteered to participate in this study and were randomly assigned to 3 SSIT groups with different work-to-rest ratios (1:2 [5-s run:10-s rest], 1:4 [5-s run:20-s rest], and 1:6 [5-s work:30-s rest]). Before and after 6-week training, physiological parameters (maximum oxygen uptake, first and second ventilatory thresholds, and peak and mean power output) and physical performance measures (ie, countermovement vertical jump, 10-m sprint, and T-test change-of-direction speed) were evaluated., Results: After the training period, all groups improved (P = .001) their sport-related performance and physiological parameters, ranging from moderate to very large effect sizes. Comparative analysis of the magnitude of training effects indicated that the 1:6 SSIT group had in a significantly greater change in countermovement vertical jump (P = .007), 10-m sprint (P = .014), peak power output (P = .019), and mean power output (P = .05) compared with 1:2 SSIT group. By contrast, the 1:2 SSIT group demonstrated significantly (P = .022) greater changes in maximum oxygen uptake than the 1:6 SSIT group. However, the change-of-direction speed and changes in first and second ventilatory thresholds were the same among the groups (P > .05)., Conclusions: When performing SSIT, longer rest intervals are suitable for physical and anaerobic performance, and shorter rest periods are appropriate for enhancing the cardiorespiratory fitness of female volleyball players' performance.

This study examined the uniformity of adaptations in cardiorespiratory fitness and bio-motor abilities by analyzing individual responses to measures representing the mentioned qualities. Twenty-four male well-trained soccer players (Age = 26 ± 4 years; stature = 181 ± 3.8; Weight = 84 ± 6.1) were randomized to two groups performing short sprint interval training [sSIT (3 sets of 10 × 4 s all-out sprints with 20 s of recovery between efforts and 3 min of rest intervals between sets)] or a time-matched small-sided game [SSG (3 sets of 3 v 3 efforts in a 20 × 15 m area with 3 min of relief in-between)]. Before and after the 6-week training period, aerobic fitness indices, cardiac hemodynamics, and anaerobic power were assessed through a graded exercise test utilizing a gas collection system, noninvasive impedance cardiography, and a lower-body Wingate test, respectively. Also, sport-specific bio-motor abilities were determined by measuring linear speed, change of direction, and jumping ability. Comparing inter-individual variability in the adaptive changes by analyzing residuals in individual adaptations indicated that sSIT induces more uniform changes in the first and second ventilatory threshold (VT 1 & VT 2 ), stroke volume, and peak power output across team members than SSG. SSG also yielded lower proportions of responders in V ˙ O 2 ⁡ max , VT 1 , VT 2 , peak, and average power output compared to sSIT. Additionally, the coefficient of variation in mean group changes in measures of aerobic fitness and bio-motor abilities in response to sSIT were lower than in SSG. Short sprint interval training induces more homogenized adaptations in measures of cardiorespiratory fitness and anaerobic power than small-sided games across team members., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Sheykhlouvand and Gharaat.)

Background: The present study evaluated the effects of aerobic training with variable intensities on apoptotic indices of cardiac tissue in fatty diabetic rats., Methods: Twenty-four male Wistar rats were randomly divided into non-diabetic (ND, n=8), trained diabetic (TD, n=8), and control diabetic (CD, n=8) groups. Following a high-fat dietary regimen, type 2 diabetes was induced by streptozotocin, with blood glucose levels above 300 mg/dL considered indicative of diabetes. The TD group underwent aerobic exercise five times a week for six weeks. Subsequently, measurements were taken for left ventricular end-diastolic (LVEDV) and end-systolic volumes (LVESV), ejection fraction (EF%), catalase, caspase-9, P53, glucose, insulin, and HOMA-IR., Results: Aerobic training led to a significant decrease in blood glucose levels (P < 0.01), caspase-9 (P < 0.05), HOMA-IR (P < 0.05), and P53 expression (P < 0.001) compared with the CD group. LVEDV and LVESV decreased significantly (P < 0.05 for both), while LVEF increased significantly (P < 0.05). Catalase activation showed an insignificant increase in the TD group pre- to post-training compared to CD., Conclusion: Incremental aerobic exercise training (6 weeks) may exert a cardioprotective effect in diabetic rats by reducing apoptosis and oxidative stress indices, while simultaneously increasing aerobic fitness and reducing body weight., Competing Interests: The authors declare that they have no financial associations or conflicts of interest pertaining to the material discussed in the manuscript.

This study examined the effects of a resistance-type high-intensity interval training (RHIIT) matched with the lowest velocity that elicited V . O 2peak (100% v V . O 2peak ) in well-trained kayak sprint athletes. Responses in cardiac structure and function, cardiorespiratory fitness, anaerobic power, exercise performance, muscular strength, and hormonal adaptations were examined. Male kayakers ( n = 24, age: 27 ± 4 years) were randomly assigned to one of three 8-wk conditions ( N = 8): (RHIIT) resistance training using one-armed cable row at 100% v V . O 2peak ; paddling-based HIIT (PHIIT) six sets of paddling at 100% v V . O 2peak ; or controls (CON) who performed six sessions including 1-h on-water paddling/sessions at 70-80% maximum HR per week. Significant increases ( p < 0.05) in V . O 2peak , v V . O 2peak , maximal cardiac output, resting stroke volume, left ventricular end-systolic dimension, 500-m paddling performance were seen pre- to post-training in all groups. Change in V . O 2peak in response to PHIIT was significantly greater ( p = 0.03) compared to CON. Also, 500-m paddling performance changes in response to PHIIT and RHIIT were greater ( p = 0.02, 0.05, respectively) than that of CON. Compared with pre-training, PHIIT and RHIIT resulted in significant increases in peak and average power output, maximal stroke volume, end-diastolic volume, ejection fraction, total testosterone, testosterone/cortisol ratio, and 1,000-m paddling performance. Also, the change in 1,000-m paddling performance in response to PHIIT was significantly greater ( p = 0.02) compared to that of CON. Moreover, maximum strength was significantly enhanced in response to RHIIT pre- to post-training ( p < 0.05). Overall, RHIIT and PHIIT similarly improve cardiac structure and hemodynamics, physiological adaptations, and performance of well-trained kayak sprint athletes. Also, RHIIT enhances cardiorespiratory fitness and muscular strength simultaneously., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sheykhlouvand, Arazi, Astorino and Suzuki.)

Background: Caffeine enhances muscle glycogen resynthesis postexercise; however, the next-day effects on recovery are unknown. The present study aimed to examine the effects of carbohydrate (CHO) supplementation with or without caffeine (CAF) 24-h following exhaustive exercise on time trial performance in elite paddling athletes., Methods: Nine highly trained male paddlers (21±2 y) completed three experimental trials in a randomized, double-blind, crossover manner. Following an exhaustive exercise session (20-km timed paddle) participants ingested: 1) 0.6 g/kg of carbohydrate (CHO); 2) 0.6 g/kg of carbohydrate with 6 mg/kg of caffeine (CAF+CHO); or 3) placebo (PLA), at four time-points (immediately after, and 2, 6, and 12-h postexercise) in addition to their typical dietary intake. After 24 h, 5 attempts of on-water 500-m paddling time-trial was performed, and the average time was recorded. Blood samples were taken at rest and following both the 20-km and the 5×500 m exercise to determine changes in plasma cortisol, insulin, and glucose., Results: There was a significant main effect of condition (P<0.001), with post-hoc analysis revealing that both CHO conditions (CHO: 98.7±2.8 s, P=0.0003; CAF+CHO: 97.9±2.3 s, P=0.0002) were significantly faster compared to PLA (101.0±3.1 s); however, CAF did not augment time trial performance compared to CHO (P=0.16). There was no significant condition by time interactions for glucose, cortisol, or insulin before and after the 20-km depleting exercise and 500-m time trial., Conclusions: In elite male paddlers, CHO, independent of caffeine, enhanced time trial performance 24 hours following exhaustive exercise.

Background: The present study determined whether 4 weeks of moderate aerobic exercise improves antioxidant capacity on the brain of rats against oxidative stress caused by radiofrequency electromagnetic radiation emitted from cell phones., Methods: Responses of malondialdehyde, catalase, glutathione peroxidase, and superoxide dismutase, as well as the number of hippocampal dead cells, were examined. Male Wistar rats (10-12 wk old) were randomly assigned to 1 of 4 groups (N = 8): (1) moderate aerobic exercise (EXE) (2 × 15-30 min at 1215 m/min speed with 5 min of active recovery between sets), (2) exposure to 900/1800 MHz radiofrequency electromagnetic waves 3 hours per day (RAD), (3) EXE + RAD, and (4) exposure to an experimental phone without battery., Results: Following the exposure, the number of the hippocampal dead cells was significantly higher in group RAD compared with groups EXE, EXE + RAD, and control group. Malondialdehyde concentration in group RAD was significantly higher than that of groups EXE, EXE + RAD, and control group. Also, the activity of catalase, glutathione peroxidase, and superoxide dismutase in groups EXE, EXE + RAD, and control group was significantly higher compared with those of the exposure group., Conclusion: This study demonstrated that moderate aerobic exercise enhances hippocampal antioxidant capacity against oxidative challenge in the form of radiofrequency electromagnetic waves.

Sheykhlouvand, M, Khalili, E, Gharaat, M, Arazi, H, Khalafi, M, and Tarverdizadeh, B. Practical model of low-volume paddling-based sprint interval training improves aerobic and anaerobic performances in professional female canoe polo athletes. J Strength Cond Res 32(8): 2375-2382, 2018-Brief, intense exercise training using running and cycling as exercise interventions may induce aerobic and anaerobic adaptations in athletes from a wide range of sports. However, this has not been studied extensively for those sports in which the upper body is predominantly involved. Our purpose was to examine the effects of kayak paddling-based sprint interval training (SIT) on cardiorespiratory fitness and anaerobic performance. Sixteen professional female canoe polo athletes (age = 27.6 ± 1.9 years; height = 165.7 ± 5.2 cm; body mass = 62.6 ± 8.5 kg; body mass index = 22.8 kg·m; body fat = 23.8 ± 4.9%) were randomized to either an intense exercise training consisting of sets of 5 × 5-second maximum sprint efforts interspersed by a 10-second recovery between each sprint (3, 4, 5, and 6 sets/session from first to fourth week, respectively, with 3 minutes of rest between each set), performed 3 times per week for 4 weeks (n = 8), or a usual training control group (n = 8). Before and after the training period, aerobic and anaerobic measurements were assessed using a kayak specific test and Wingate protocol, respectively. Training increased V[Combining Dot Above]O2peak, O2 pulse, anaerobic threshold, peak, and mean power output in the SIT group compared with the control group (p ≤ 0.05) who showed no changes in these variables when tested 4 weeks apart without SIT. Paddling-based SIT was a potent stimulus and time-efficient strategy to induce rapid adaptations in aerobic and anaerobic performances in professional female canoe polo athletes who can use this training method to achieve fitness in a short period.

Sheykhlouvand, M, Gharaat, M, Khalili, E, Agha-Alinejad, H, Rahmaninia, F, and Arazi, H. Low-volume high-intensity interval versus continuous endurance training: effects on hematological and cardiorespiratory system adaptations in professional canoe polo athletes. J Strength Cond Res 32(7): 1852-1860, 2018-The aim of this study was to compare the effect of 2 paddling-based high-intensity interval training (HIIT) and continuous endurance training (CET) on hematological, immunological, and cardiorespiratory adaptations in professional canoe polo athletes. A total of 21 male canoe polo athletes were randomly divided into 1 of 3 groups (N = 7): (a) HIIT with variable intensity (VIHIIT) (6 × 60 seconds at 100, 110, 120, 130, 130, 130, 120, 110, 100% vV[Combining Dot Above]O2peak from first to ninth session, respectively, 1:3 work to recovery ratio); (b) HIIT with variable volume (VVHIIT) (6, 7, 8, 9, 9, 9, 8, 7, 6 repetitions/session from first to ninth session, respectively) × 60 seconds at lowest velocity that elicited V[Combining Dot Above]O2peak (vV[Combining Dot Above]O2peak), 1:3 work to recovery ratio); and (c) the CET group performed 3 times × 60 minutes paddling sessions (75% vV[Combining Dot Above]O2peak) per week for 3 weeks. Significant increases in V[Combining Dot Above]O2peak (ml·kg·min) (VIHIIT = 7.6%, VVHIIT = 6.7%), ventilation (V[Combining Dot Above]E) at V[Combining Dot Above]O2peak (VIHIIT = 11.5%, VVHIIT = 15.2%), respiratory frequency (Rf) at V[Combining Dot Above]O2peak (VVHIIT = 21.1%), V[Combining Dot Above]O2 at ventilatory threshold (VT) (VIHIIT = 10.5%, VVHIIT = 25.1%), V[Combining Dot Above]E at VT (VIHIIT = 12.4%, VVHIIT = 34.0%), tidal volume at VT (VIHIIT = 11.7%, VVHIIT = 33.3%), Rf at VT (VIHIIT = 9.7%), V[Combining Dot Above]E/V[Combining Dot Above]O2 at VT (VVHIIT = 13.1%), V[Combining Dot Above]O2/heart rate (HR) at VT (VIHIIT = 12.9%, VVHIIT = 21.4%), and V[Combining Dot Above]E/HR at VT (VIHIIT = 7.8%, VVHIIT = 27.2%) were seen compared with pretraining. Training interventions resulted in significant increases in mean platelet volume (VIHIIT = 2.7%, VVHIIT = 1.9%), mean corpuscular hemoglobin concentration (CET = 3.3%), and significant decrease in red blood cell distribution width (VVHIIT = -4.3), and cell numbers of lymphocyte (CET = -27.1) compared with pretraining. This study demonstrated that paddling-based HIIT enhances aerobic capacity and respiratory makers, without negatively affecting the immune system over 3 weeks.

This study compared the effects of 2 different high-intensity interval training (HIIT) programs in professional male canoe polo athletes. Responses of peak oxygen uptake (VO2peak), ventilatory threshold (VT), peak and mean anaerobic power output (PPO and MPO), blood volume, and hormonal adaptations to HIIT were examined. Male athletes (n = 21, age: 24 ± 3 years; height: 181 ± 4 cm; mass: 85 ± 6 kg; and body fat: 12.9 ± 2.7%) were randomly assigned to one of 3 groups (N = 7): (a) (G1) interval paddling with variable volume (6, 7, 8, 9, 9, 9, 8, 7, 6 repetitions per session from first to ninth session, respectively) × 60 second at lowest velocity that elicited VO2peak (vVO2peak), 1:3 work to recovery ratio; (b) (G2) interval paddling with variable intensity (6 × 60 second at 100, 110, 120, 130, 130, 130, 120, 110, 100% vVO2peak from first to ninth session, respectively, 1:3 work to recovery); and (c) (GCON) the control group performed three 60 minutes paddling sessions (75% vVO2peak) per week for 3 weeks. High-intensity interval training resulted in significant (except as shown) increases compared with pretest, in VO2peak (G1 = +8.8% and G2 = +8.5%), heart rate at VT (b·min) (G1 = +9.7% and G2 = +5.9%) and (%maximum) (G1 = +6.9%; p = 0.29 and G2 = +6.5%), PPO (G1 = +9.7% and G2 = +12.2%), MPO (G1 = +11.1%; p = 0.29 and G2 = +16.2%), total testosterone (G1 = +29.4% and G2 = +16.7%), total testosterone/cortisol ratio (G1 = +40.9% and G2 = +28.1%), and mean corpuscular hemoglobin (G1 = +1.7% and G2 = +1.3%). No significant changes were found in GCON. High-intensity interval paddling may improve both aerobic and anaerobic performances in professional male canoe polo athletes under the conditions of this study.