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Purpose: To characterize the time structure of K1 kickboxing matches of Glory World Series (Glory) and to determine potential differences between winners and losers. Methods: Seventeen matches of Glory 2019 (17 first rounds, 13 second rounds, and 8 third rounds) were video-analyzed to quantify (1) the time expended in high- and low-intensity activity and pauses, (2) the number and pattern of attacks, and (3) the number of effective attacks. Fighters were professional male athletes (age 27.9 [2.7] y) of the middle-weight category (85 kg). The number and the pattern of attacks and the number of effective attacks were compared between winners and losers. Results: The mean times expended in high- and low-intensity activity and pauses were 234.6 (133.9) seconds, 97.4 (60.1) seconds, and 36.0 (19.9) seconds, respectively, resulting in an effort-to-pause ratio of ∼1.8:1. Compared with losers, winners presented (1) a greater number of attacks in the second round (P =.004) and entire match (P =.009), (2) a greater number of attacks containing 3 attacks in sequence in the second round (P =.001) and attacks containing >3 attacks in the third round (P =.049), and (3) a greater number of effective attacks in the second round (P =.011) and entire match (P =.008). Conclusions: The findings of the present study indicate that K1 kickboxing in Glory matches presents a ∼1.8:1 effort-to-pause ratio and that winners perform more attacks, effective attacks, and attacks in sequence. These data provide useful insights to improve the training specificity of kickboxing athletes. [ABSTRACT FROM AUTHOR]

There is a lack of evidence on the additional benefits of combining caffeine (CAF) and creatine (CRE) supplementation on anaerobic power and capacity. Thus, the aim of the present study was to test the effects of combined and isolated supplementation of CAF and CRE on anaerobic power and capacity. Twenty-four healthy men performed a baseline Wingate anaerobic test and were then allocated into a CRE (n = 12) or placebo (PLA; n = 12) group. The CRE group ingested 20 g/day of CRE for 8 days, while the PLA group ingested 20 g/day of maltodextrin for the same period. On the sixth and eighth days of the loading period, both groups performed a Wingate anaerobic test 1 hr after either CAF (5 mg/kg of body mass; CRE + CAF and PLA + CAF conditions) or PLA (5 mg/kg of body mass of cellulose; CRE + PLA and PLA + PLA conditions) ingestion. After the loading period, changes in body mass were greater (p <.05) in the CRE (+0.87 ± 0.23 kg) than in the PLA group (+0.13 ± 0.27 kg). In both groups, peak power was higher (p =.01) in the CAF (1,033.4 ± 209.3 W) than in the PLA trial (1,003.3 ± 204.4 W), but mean power was not different between PLA and CAF trials (p >.05). In conclusion, CAF, but not CRE ingestion, increases anaerobic power. Conversely, neither CRE nor CAF has an effect on anaerobic capacity. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated the effects of previous exhaustive upper body exercise on performance and neuromuscular fatigue following a 4-km cycling time-trial (4-km TT). Methods: Eight recreational cyclists performed a 4-km TT with (ARM[subscript PRE]) or without (CONTR) a previous arm-crank maximal incremental test. In each experimental session, neuromuscular fatigue was evaluated with a series of electrically evoked and maximal voluntary isometric contractions (MVC). Oxygen uptake (VO[subscript 2]), heart rate, electromyographic muscle activity (EMG[subscript RMS]) and rating of perceived exertion (RPE) were also recorded throughout the 4-km TT. Results: The average power output during the 4-km TT was reduced (P = 0.027) for the ARM[subscript PRE] (299 ± 59 W) group, compared with CONTR (310 ± 59 W) and overall performance in 4-km TT was impaired (P = 0.021) in ARM[subscript PRE] (382 ± 28 s) compared with CONTR (376 ± 27 s). The decrease observed in MVC (P = 0.033) and potentiated peak twitch force (P = 0.004) at post-TT were similar between the ARM[subscript PRE] and CONTR conditions (P = 0.739 and P = 0.493, respectively). There was no (P = 0.619) change in voluntary activation at post-TT between conditions. VO[subscript 2], EMG[subscript RMS] and RPE measured throughout the 4-km TT were not significantly different between the conditions (P = .558, P = 0.558 and P = 0.940, respectively). The rate of RPE change relative to power output average and heart rate was higher (P = 0.030 and P = 0.013, respectively) in ARM[subscript PRE] (0.031 ± 0.018 AU/W and 168 ± 8 bpm) than CONTR (0.022 ± 0.010 AU/W and 161 ± 7 bpm). Conclusion: These results suggest that impaired performance in ARM[subscript PRE] was mostly due to pronounced perception of effort rather than neuromuscular fatigue.

Objective: To investigate the acute effects of ingesting a beverage containing guarana (Paullinia cupana) seed powder on performance during field tests related to physical capacities that are determinants of soccer performance, such as lower limb power, sprint, agility, and the capacity to carry out intermittent exercise. Methods: The study was conducted using a randomized, crossover, and counterbalanced design, with a beverage containing guarana or placebo administered in a double-blind manner. Twenty-seven under-17 soccer players of a professional soccer club performed a battery of tests 60 min after the ingestion of guarana (3 g of the fruit seed powder) or placebo. Trials were performed with a 7-day washout period. The battery of tests included a countermovement jump test, sprints of 10 and 20 m, an Illinois agility test, and a Yo–Yo Intermittent Recovery Test level 1 (YYIR1). Results: Guarana ingestion did not improve countermovement jump, sprints, or agility (p > 0.05). However, guarana ingestion increased the distance covered in the YYIR1, compared with placebo ingestion (p = 0.01). Conclusion: Acute ingestion of guarana improves the capacity to perform intermittent exercise in soccer players but seems to be ineffective to improve lower limb power, sprint, and agility. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of caffeine (CAF) on performance during high- and long-jump competitions. Methods: Using a crossover and double-blind design, 6 well-trained high jumpers and 6 well-trained long jumpers performed a simulation of a high- and long-jump competition 60 minutes after ingesting a capsule containing either 5 mg·kg−1 body mass of anhydrous CAF or a placebo. The high jumps were video recorded for kinematic analysis. The velocity during the approach run of the long jump was also monitored using photocells. Results: CAF improved jump performance (ie, the highest bar height overlap increased by 5.1% [2.3%], P =.008), as well as enhancing the height displacement of the central body mass (+1.3% [1.7%], P =.004) compared with the placebo. CAF had no ergogenic effect on jump distance (P =.722); however, CAF increased the velocity during the last 10 m of the long jump (P =.019), and the percentage of "foul jumps" was higher than that expected by chance in the CAF group (80.5% [12.5%], χ2 = 13.44, P <.001) but not in the cellulose condition (58.3% [22.9%], χ2 = 1.48, P =.224). Conclusion: CAF ingestion (5 mg·kg−1 body mass) improves high-jump performance but seems to negatively influence technical aspects during the approach run of the long jump, resulting in no improvement in long-jump performance. Thus, CAF can be useful for jumpers, but the specificity of the jump competition must be taken into account. [ABSTRACT FROM AUTHOR]

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The effects of plyometric training (PT) on middle- and long-distance running performances are well established. However, its influence on pacing behaviour is still unclear. The aim of this study was to evaluate the effects of PT on pacing behaviour. In addition, verify whether the adaptations induced by PT would change ratings of perceived exertion (RPE) and/or affective feelings during the race. Twenty-eight male runners were assigned to two groups: control (C) and PT. PT held two weekly PT sessions for eight weeks. Drop jump (DJ) performance, 10-km running performance, pacing behaviour, RPE and affective feelings, VO2peak, ventilatory thresholds (VT1 and VT2), peak treadmill speed (PTS), and running economy (RE) were measured. For group comparisons, a mixed model analysis for repeated measures, effect size (ES) and 90% confidence interval (90% CI) were calculated for all dependent variables. Significant differences pre-to-post was observed for PT group in DP (7.2%; p ≤ 0.01; ES = 0.56 (0.28–0.85)) and RE (4.5%; p ≤ 0.05; ES = −0.52 ((−0.73 to −0.31)) without changes in pacing behaviour. While PT was effective for improving DJ and RE, there is no evidence that pacing behaviour, RPE or affective feelings are directly affected by these adaptations during a 10-km time trial run. [ABSTRACT FROM AUTHOR]

This study analyzed the effect of an acute static stretching bout on the time to exhaustion ([T.sub.lim]) at power output corresponding to V[O.sub.2]max. Eleven physically active male subjects (age 22.3 [+ or -] 2.8 years, V[O.sub.2]max 2.7 [+ or -] 0.5 L x [min.sup.-1]) completed an incremental cycle ergometer test, 2 muscle strength tests, and 2 maximal tests to exhaustion at power output corresponding to V[O.sub.2]max with and without a previous static stretching bout. The [T.sub.lim] was not significantly affected by the static stretching (164 [+ or -] 28 vs. 150 [+ or -] 26 seconds with and without stretching, respectively, p = 0.09), but the time to reach V[O.sub.2]max (118 [+ or -] 22 vs. 102 [+ or -] 25 seconds), blood-lactate accumulation immediately after exercise (10.7 [+ or -] 2.9 vs. 8.0 [+ or -] 1.7 mmol x [L.sup.-1]), and oxygen deficit (2.4 [+ or -] 0.9 vs. 2.1 [+ or -] 0.7 L) were significantly reduced (p [less than or equal to] 0.02). Thus, an acute static stretching bout did not reduce [T.sub.lim] at power output corresponding to V[O.sub.2]max possibly by accelerating aerobic metabolism activation at the beginning of exercise. These results suggest that coaches and practitioners involved with aerobic dependent activities may use static stretching as part of their warm-up routines without fear of diminishing high-intensity aerobic exercise performance. KEY WORDS strength, flexibility, oxygen-deficit, lactate, aerobic metabolism

This study tested the concurrent and construct validity of a newly developed OMNI-Kayak Scale, testing 8 male kayakers who performed a flatwater load-incremented 'shuttle' test over a 500-m course and 3 estimation-production trials over a 1,000-m course. Velocity; blood lactate concentration, heart rate, and rating of perceived exertion (RPE), using the OMNI-Kayak RPE Scale and the Borg 6-20 Scale were recorded. OMNI-Kayak Scale RPE was highly correlated with velocity, the Borg 6-20 Scale RPE, blood lactate, and heart rate for both load-incremented test (rs = .87-.96), and estimation trials (rs = .75-.90). There were no significant differences among velocities, heart rate and blood lactate concentration between estimation and production trials. The OMNI-Kayak RPE Scale showed concurrent and construct validity in assessing perception of effort in flatwater kayaking and is a valid tool for self-regulation of exercise intensity.