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This study investigated whether a heavy-intensity priming exercise precisely prescribed within the heavy-intensity domain would lead to a greater peak-power output (POpeak) and a longer maximal oxygen uptake (V̇ o 2max) plateau. Twelve recreationally active adults participated in this study. Two visits were required: 1) a step-ramp-step test [ramp-incremental (RI) control], and 2) an RI test preceded by a priming exercise within the heavy-intensity domain (RI primed). A piecewise equation was used to quantify the V̇ o 2 plateau duration (V̇ o 2plateau-time). The mean response time (MRT) was computed during the RI control condition. The delta (Δ) V̇ o 2 slope (S; mL·min−1·W−1) and V̇ o 2-Y intercept (Y; mL·min−1) within the moderate-intensity domain between conditions (RI primed minus RI control) were also assessed using a novel graphical analysis. V̇ o 2plateau-time (P = 0.001; d = 1.27) and POpeak (P = 0.003; d = 1.08) were all greater in the RI primed. MRT (P < 0.001; d = 2.45) was shorter in the RI primed compared with the RI control. A larger ΔV̇ o 2plateau-time was correlated with a larger ΔMRT between conditions (r = –0.79; P = 0.002). This study demonstrated that heavy-intensity priming exercise lengthened the V̇ o 2plateau-time and increased POpeak. The overall faster RI-V̇ o 2 responses seem to be responsible for the longer V̇ o 2plateau-time. Specifically, a shorter MRT, but not changes in RI-V̇ o 2-slopes, was associated with a longer V̇ o 2plateau-time following priming exercise. NEW & NOTEWORTHY: It remains unclear whether priming exercise extends the maximal oxygen uptake (V̇ o 2max) plateau and increases peak-power output (POpeak) during ramp-incremental (RI) tests. This study demonstrates that a priming exercise, precisely prescribed within the heavy-intensity domain, extends the plateau at V̇ o 2max and leads to a greater POpeak. Specifically, the extended V̇ o 2max plateau was associated with accelerated RI-V̇ o 2 responses. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of drop jumps (DJs) on performance time and pacing in a field test (ie, 1000 m) commonly used to evaluate endurance runners and to evaluate running and jumping performance in male and female athletes separately. Methods: Twenty elite endurance runners (male, n = 10, 27.8 [7.0] y, 62.3 [5.2] kg; female, n = 10, 25.9 [5.3] y, 51.7 [4.1] kg) competing in middle- and long-distance events participated in this study. After determination of the box height associated with the best reactive strength index, athletes randomly performed a warm-up with or without the inclusion of 5 DJs with the highest reactive strength index prior to a 1000-m track test. Performance time and pacing (250-m splits) were determined. Countermovement-jump heights at different time points and blood lactate concentration after running tests were also recorded. Results: A "possible" faster 1000-m time (162.4 vs 165.3 s) with a "very likely" faster first split (38.8 vs 40.3 s) was observed in male athletes in the DJ condition. In contrast, female athletes showed a "possible" slower running time (186.8 vs 184.8 s) and a "likely" greater blood lactate concentration after the 1000-m test in the DJ condition. Male and female athletes presented greater countermovement-jump performances after warm-up and running tests in both conditions. Conclusions: The inclusion of 5 DJs with the height associated with the best reactive strength index induced a "possible" improvement in 1000-m performance time in elite male endurance runners. The current protocol should be avoided in female athletes. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the outcomes from 2 weeks of training load intensification strategy in female water polo players diagnosed with functional overreaching (F-OR) with no F-OR players (acute fatigue) on the performance outcomes and hormonal, immunological, and cardiac autonomic nervous system responses. Twenty-two female water polo players were allocated into control and intensification group during 7 weeks. The swimming performance, biochemical parameters, heart rate variability, profile of mood states, and upper respiratory tract infection symptoms were assessed twice before and twice after 2 weeks of intensification period. F-OR showed a worsening in total time of the repeated sprint ability (RSA) test compared with the control group and the acute fatigue group after intensification (p = 0.035). Furthermore, after the tapering period, the F-OR group maintained worse total time of the RSA test than the acute fatigue group (p = 0.029). In addition, the acute fatigue group showed improvement in total time of the RSA test after intensification compared with the control group (p < 0.001). No significant interactions were found for the other parameters. Therefore, periods of intensification without the F-OR development can promote higher gains in the total time of the RSA test after intensification and tapering period. [ABSTRACT FROM AUTHOR]

We aimed to compare the effects of beta-alanine on Traditional Resistance Training (TRAD) or Blood Flow Restriction Training (BFR). Methods: 19 subjects were randomly allocated to a Placebo (n = 10) or beta-alanine (n = 9) group. Subjects from both groups were trained unilaterally (unilateral arm curl) for six weeks, and each arm was trained using a different paradigm (BFR or TRAD). One repetition maximum (1RM) test measurements were performed before and after the strength training program. Work output was accessed as the total weight lifted (repetitions × weight lifted × sets) for the entire strength training program. Results: 1RM or total weight lifted was not increased by beta-alanine supplementation. However, the TRAD-trained arm showed a significantly increased 1RM and total weight lifted compared to the BFR arm (p < 0.05). Conclusion: We conclude that in the short-term (6 weeks) and following the current experimental conditions, beta-alanine does not benefit BFR or TRAD in terms of total weight lifted (volume of training) or maximal strength (1RM). [ABSTRACT FROM AUTHOR]

The purpose of this study was to verify the physiological responses and the match characteristics of table tennis and also to compare these responses in 2 different performance-level athletes from official tournaments. Twenty male table tennis players (12 regional experience--RP and 8 national and international experience--NP) were participants in the study. Blood lactate concentration ([LAC]) and heart rate (HR) were measured as physiological parameters in 21 official table tennis matches, and other 12 matches had recorded the duration of rally (DR), rest time, effort and rest ratio (E:R), total playing time (TPT), effective playing time (EPT), and frequency of shots by video analyses. The [LAC] verified in all matches was 1.8 mmol x [L.sup.-1] ([+ or -]0.8), whereas the [LAC] peak was 2.2 mmol x [L.sup.-1] ([+ or -]0.8). There were no significant differences between the 2 groups (p > 0.05) in both parameters. The HR was 164 b x [min.sup.-1] ([+ or -] 14), corresponding to 81.2% ([+ or -] 7.4) of the predicted maximum HR. As characteristics of the matches, the DR corresponded to 3.4 seconds ([+ or -]1.7), rest time to 8.1 seconds ([+ or -]5.1), E:R to 0.4 ([+ or -]0.2), TPT to 970.5 seconds ([+ or -]336.1), EPT to 44.3% ([+ or -]23.7), and frequency of shots to 35.3 balls x [min.sup.-1] ([+ or -]7.7). Among groups, the rest time was lower in RP than in NP. Consistently, the E:R and EPT were higher in RP than in NP (p < 0.05). The results suggest that table tennis matches present the aerobic system as a principal output energy, the phosphagenic system being the most important during efforts. The information pertaining to the physiological profile and the characteristics of table tennis should be used by coaches planning physical training and specific exercise prescriptions aiming at achieving maximal sport performance. KEY WORDS lactate, duration of rally, effort and rest ratio, aerobic system, racket sports

The purpose of this study was to investigate the reliability and validity of the running anaerobic sprint test (RAST) in anaerobic assessment and predicting short-distance performance. Forty members of the armed forces were recruited for this study (age 19.78 [+ or -] 1.18 years; body mass 70.34 [+ or -] 8.10 kg; height 1.76 [+ or -] 0.53 m; body fat 15.30 [+ or -] 5.65%). The RAST test was applied to six 35-meter maximal running performances with a 10-second recovery between each run; the peak power, mean power, and the fatigue index were measured. The study was divided in two stages. The first stage investigated the reliability of the RAST using a test-retest method; the second stage aimed to evaluate the validity of the RAST comparing the results with the Wingate test and running performances of 35, 50, 100, 200, and 400 m. There were not significant differences between test-retest scores in the first stage of the study (p > 0.05) and were found significant correlations between these variables (intraclass correlation coefficient [congruent to]0.88). The RAST had significant correlations with the Wingate test (peak power r = 0.46; mean power r = 0.53; fatigue index r = 0.63) and 35, 50, 100, 200, and 400 m performances scores (p < 0.05). The advantage of using the RAST for measuring anaerobic power is that it allows for the execution of movements more specific to sporting events that use running as the principal style of locomotion, is easily applied and low cost, and due to its simplicity can easily be incorporated into routine training. We concluded that this procedure is reliable and valid, and can be used to measure running anaerobic power and predict short-distance performances. KEY WORDS running test, anaerobic component, running performance, Wingate test, lactate

The study aimed to identify and quantify the metabolites profile and metabolic pathways in human muscle tissue engaged during exhaustive high‐intensity cycling exercise. Seven healthy physically active men performed a graded exercise test and an exhaustive supramaximal effort at 115% of maximal aerobic power with muscles biopsies performed in rest and immediately after exhaustion for quantifying of muscle metabolites changes by 1H‐NMR spectroscopy. The time until exhaustion (tlim) recorded was 224.7 ± 35.5 s whereas the muscle pH at exhaustion was 6.48 ± 0.05. A total of 54 metabolites were identified and quantified. The most enriched and impacted pathways included: beta oxidation of very long chain fatty acids, mitochondrial electron transport chain, alanine aspartate, and glutamate metabolism, citric acid cycle, arginine biosynthesis, propanoate metabolism, threonine and 2‐oxobutanoate degradation and pyruvate metabolism. In addition, the muscle concentrations in Post exercise, compared to Pre increased significantly (p < 0.0398) for fumarate (42.0%), succinate (101.2%), glucose (249.7%), lactate (122.8%), O‐acetylcarnitine (164.7%), glycerol (79.3%), AMP (288.2%), 2‐oxobutyrate (121.0%), and methanol (58.5%), whereas decreased significantly (p < 0.010) for creatine phosphate (−70.2%), ADP (−56.5%), carnitine (−33.5%), and glutamate (−42.3%). Only the succinate was significantly correlated with tlim (r = −0.76; p = 0.0497). Besides the classical expected contribution of glycolytic and phosphagen energetic pathways, it was demonstrated that the high‐intensity exercise is also associated with pathways indicatives of amino acid and fatty acid oxidation metabolisms, highlighting the inverse relation between changes in the intramuscular succinate levels and tlim. [ABSTRACT FROM AUTHOR]

Objective: To investigate the recovery of male water polo athletes applying full body photobiomodulation therapy (PBMT) regarding inflammation and muscle damage markers, testosterone and cortisol hormonal responses, heart rate variability (HRV), maximal voluntary contraction, and squat jump (SJ) after official water polo matches. Background: PBMT has been applied locally on specific muscle groups to induce faster recovery and improve the performance of athletes and nonathletes. However, many sports modalities require movement of the whole body, and a full body PBMT could be more adequate to irradiate large muscle areas homogeneously and faster. Methods: In a randomized, parallel, and double-blinded design, 13 athletes (whole team) aged 18 years attended the study and were allocated into two groups: PBMT (dose of 6.9 J/cm2, irradiance of 46.17mW/cm2, 5 min irradiation) and placebo treatment. The study was conducted during the 2019 Brazilian under 20 water polo championship. All athletes were assessed by blood samples and neuromuscular evaluation. Immediately after each match, all athletes received PBMT (effective or placebo). Results: No significant interactions (raw values and percentage related to baseline) were observed for testosterone and cortisol, tumor necrosis factor-alpha, interleukin-6, creatine kinase concentration, maximal isometric voluntary contraction, SJ test, and HRV. Only an isolated interaction (decrease) was found for lactate dehydrogenase (LDH) response after the first match (p = 0.004, post-hoc p = 0.038). Conclusions: The parameters of the full body PBMT of this study did not induce faster recovery of inflammatory, muscle damage (excepting LDH), testosterone, cortisol, HRV, and neuromuscular responses during repeated days of water polo matches. [ABSTRACT FROM AUTHOR]

Ankle muscle fatigue has been shown to increase body sway. In addition, body sway in quiet upright standing is reduced when saccadic eye movements are performed. The purpose of this study was to investigate the effects of visual information manipulation on postural control during ankle muscle fatigue in young adults. Twenty young adults performed: (1) two 60-s trials in quiet bipedal standing with eyes open, eyes closed, and while performing saccadic eye movements; (2) maximum voluntary isometric contractions in a leg press device, custom-made to test ankle plantar flexion force; (3) a calf raise exercise on top of a step to induce ankle muscle fatigue; and (4) a repetition of items 1 and 2. Postural sway parameters were compared with two-way ANOVAs (vision condition × fatigue; p < 0.05). Ankle muscle fatigue increased anterior-posterior and medial-lateral displacement and RMS of sway, as well as sway area. Saccadic eye movements reduced anterior-posterior displacement and RMS of sway and area of sway compared to eyes open and eyes closed conditions. Both saccadic eye movements and eyes closed increased the frequency of AP sway compared to the eyes open condition. Finally, anterior-posterior displacement, anterior-posterior RMS, and both anterior-posterior and medial-lateral sway frequency were affected by an interaction of fatigue and vision condition. Without muscle fatigue, closing the eyes increased anterior-posterior displacement and RMS of sway, compared to eyes open, while during muscle fatigue closing the eyes closed reduced anterior-posterior displacement and had no significant effect on anterior-posterior RMS. In conclusion, body sway was increased after induction of ankle muscle fatigue. Saccadic eye movements consistently reduced postural sway in fatigued and unfatigued conditions. Surprisingly, closing the eyes increased sway in the unfatigued condition but reduced sway in the fatigued condition. [ABSTRACT FROM AUTHOR]

The aim of the investigation was to verify the validity and reliability of a low-end 50-Hz Global Navigation Satellite System receiver (GNSSr) for different soccer-specific run distances and average speed assessments. Six soccer players were assessed on two different days while performing eight different running paths with changes of direction for a final total of 44 runs. During the runs, each participant was equipped with the GNSSr, while the time for each single run was recorded using a photocell gate. Reference vs. receiver assessment correspondences for distance and average speed were evaluated by calculating the standard error of the estimate (SEE), coefficient of variation (CV), and mean bias. Residual vs. predicted value comparison was performed by means of Bland-Altman plots. Finally, calculating the intra-class correlations coefficient (ICC) assessed the test-retest reliability of the measurement. Receiver distance assessment showed an SEE of 0.52 m (0.73%), and mean bias of 0.06 m. Receiver average speed assessment showed an SEE of 0.02 m·s-1 (0.74%) and mean bias of 0.001 m·s-1. The Bland-Altman plot showed a small difference between the two assessments with the 95% limits of agreement=±1.08 m/0.046 m·s-1. Receiver distance/speed assessment was found to be reliable, with ICC=0.999. In spite of its low cost, the new low-end GNSSr provides valid and reliable assessments of distance and average speed for young adults performing several standardized running actions of differing lengths within delimited setup spaces. [ABSTRACT FROM AUTHOR]

In table tennis, motor skills are crucial for discriminating player level. However, there is a dearth of studies exploring the impact of a vibrational stimulus on performance. Thirty-four male players (age 25±2 years; body mass index, BMI 23.4±1.2 kg⋅m-2) participated in the study. Seventeen played at international level (IL), while the remaining 17 played at national level (NL). The participants underwent a ball-handling test, the ball score, before (PRE) and after (POST) a vibrational stimulus. Intra-class correlation (ICC) for the ball score result showed good reliability (ICC 0.87 for IL and 0.80 for NL). Repeated measures ANOVA showed differences between groups for ball score (p=0.000) and a significant group x time interaction (p=0.004). Better performances were observed for the IL group than for the NL group, significantly only for POST. Vibration produced positive and negative effects in IL and NL groups, respectively. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of prior LED sessions on the responses of cardiorespiratory parameters during the running incremental step test. Twenty-six healthy, physically active, young men, aged between 20 and 30 years, took part in this study. Participants performed two incremental load tests after placebo (PLA) and light-emitting diode application (LED), and had their gas exchange, heart rate (HR), blood lactate, and rating of perceived exertion (RPE) monitored during all tests. The PLA and LED conditions were compared using the dependent Student t test with significance set at 5%. The T test showed higher maximum oxygen uptake (VO2max) (PLA = 47.2 ± 5.7; LED = 48.0 ± 5.4 ml kg-1 min-1, trivial effect size), peak velocity (Vpeak) (PLA = 13.4 ± 1.2; LED = 13.6 ± 1.2 km h-1, trivial effect size), and lower maximum HR (PLA = 195.3 ± 3.4; LED = 193.3 ± 3.9 b min-1, moderate effect size) for LED compared to PLA conditions. Furthermore, submaximal values of HR and RPE were lower, and submaximal VO2 values were higher when LED sessions prior to the incremental step test were applied. A positive response of the previous LED application in the blood lactate disappearance was also demonstrated, especially 13 and 15 min after the test. It is concluded that LED sessions prior to exercise modify cardiorespiratory response by affecting running tolerance during the incremental step test, metabolite clearance, and RPE. Therefore, LED could be used as a prior exercise strategy to modulate oxidative response acutely in targeted muscle and enhance exercise tolerance. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to compare the contributions of the anaerobic pathway as determined by two different methods and energy expenditure during a typical high-intensity intermittent exercise (HIIE) protocol. Methods: A descriptive research design was utilized in which thirteen physically active men performed six experimental sessions consisting of an incremental test (session 1), submaximal tests at 40, 50, 60, 70, 75, 80, 85, 90% of velocity associated with maximum oxygen uptake (v V ˙ O2max) with two intensities per session (sessions 2–5), and the HIIE protocol (session 6; 10 efforts of 1 min at v V ˙ O2max interspersed by 1 min of passive recovery). The estimation of anaerobic energy system contribution was calculated by: (a) the excess post-exercise oxygen consumption plus delta lactate method and (b) the accumulated oxygen deficit method using the difference between predicted oxygen demand from the submaximal tests of varying intensities and accumulated oxygen uptake during HIIE. Estimation of aerobic energy system contribution was calculated through the measurement of oxygen consumption during activity. Total EE during the entire HIIE protocol (efforts + recovery) and for the efforts only were calculated from each method. Results: For efforts + recovery and efforts only, anaerobic contribution was similar for both methods, and consequently total EE was also equivalent (p = 0.230 for both comparisons). During efforts + recovery, aerobic:anaerobic energy system contribution was (68 ± 4%: 32 ± 4%), while efforts only was (54 ± 5%: 46 ± 5%) with both situations demonstrating greater aerobic than anaerobic contribution (p < 0.001 for both). Conclusion: Anaerobic contribution seems to be relevant during HIIE and must to be taken into account during total EE estimation; however, the type of method employed did not change the anaerobic contribution or total EE estimates. [ABSTRACT FROM AUTHOR]

Cycling test such Wingate anaerobic test (WAnT) is used to measure anaerobic power (AP), but not anaerobic capacity (AC, i.e., the metabolic energy demand). However, in sports that do not involve cycling movements (Karate), the continuous jump for 30 s (vertical jumps for 30 s) has been extensively used to measure anaerobic performance in all young athletes. Limited information's are available concerning its validity and reliability especially in children. As such, the current study aimed to test validity and reliability of a continuous jumps test (the CJ30s), using WAnT as a reference. Thirteen female Karate kids (age: 11.07 ± 1.32 years; mass: 41.76 ± 15.32 kg; height: 152 ± 11.52 cm; training experience: 4.38 ± 2.14 years) were tested on three separate sessions. The first and second sessions were used to assess the reliability using Intra-class correlation coefficient (ICC) of CJ30s, whereas on the third session WAnT was administered. Following CJ30s and WAnT, we assessed AP (1/CJ30s, as jump height [JH], fatigue index [FI], and blood lactate [BL]; 2/WAnT, as mechanical power [P], FI, and BL) and AC as the excess post-exercise oxygen consumption (EPOC). Large/highly significant correlations were found between CJ30s and WAnT EPOCs (r = 0.730, P = 0.003), and BLs (r = 0.713, P = 0.009). Moderate/significant correlations were found between CJ30s and WAnT FIs (r = 0.640, P = 0.014), CJ30s first four jumps mean JH and WAnT peak P (r = 0.572, P = 0.032), and CJ30s mean JH and WAnT mean P (r = 0.589, P = 0.021). CJ30s showed excellent and moderate reliability (ICC) for AP (maximal JH 0.884, mean JH 0.742, FI 0.657, BL 0.653) and AC (EPOC 0.788), respectively. Correlations observed especially in terms of AC between CJ30s and WAnT provide evidence that former may adequately assess anaerobic performance for the young combat athlete. CJ30 is a reliable test and allow an easy assessment of AP and AC in karate children. [ABSTRACT FROM AUTHOR]

The purpose of the study was to investigate the sensitivity of an alternative maximal accumulated oxygen deficit (MAODALT) method to discriminate the "anaerobic" capacity while comparing: least trained (LT) participants (n = 12), moderately trained (MT) participants (n = 12), endurance trained (ET) participants (n = 16), and rugby (RG) players (n = 11). Participants underwent a graded exercise test on a treadmill and a supramaximal effort for assessing MAODALT. MAODALT was calculated as the sum of oxygen equivalents from the phosphagen and glycolytic metabolic pathways. MAODALT was significantly higher (P < 0.05) in RG (64.4 ± 12.1 mL · kg-1) than in ET (56.8 ± 5.4 mL · kg-1; effect size [ES] = 0.77; +13.5%), MT (53.8 ± 5.3 mL · kg-1; ES = 1.08; +19.8%), and LT (49.9 ± 4.5 mL · kg-1; ES = 1.50; +36.4%). In addition, the magnitude-based inference analysis revealed that MAODALT was likely (LT vs. MT), very likely (MT vs. RG, and ET vs. RG) and most likely (LT vs. ET, and LT vs. RG) different between all groups, except for MT and ET, which presented an unclear difference. In conclusion, MAODALT was sensitive enough to distinguish the "anaerobic" capacity in individuals with different training status, especially for RG players compared with LT participants and MT participants. [ABSTRACT FROM AUTHOR]

Identifying the trajectory and spin of the ball with speed and accuracy is critical for good performance in table tennis. The aim of this study was to analyze the ability of table tennis players presenting different levels of training/experience to identify the magnitude of the ball spin from the sound produced when the racket hit the ball. Four types of 'forehand' contact sounds were collected in the laboratory, defined as: Fast Spin (spinning ball forward at 140 r/s); Medium Spin (105 r/s); Slow Spin (84 r/s); and Flat Hit (less than 60 r/s). Thirty-four table tennis players of both sexes (24 men and 10 women) aged 18-40 years listened to the sounds and tried to identify the magnitude of the ball spin. The results revealed that in 50.9% of the cases the table tennis players were able to identify the ball spin and the observed number of correct answers (10.2) was significantly higher (χ2 = 270.4, p <0.05) than the number of correct answers that could occur by chance. On the other hand, the results did not show any relationship between the level of training/experience and auditory perception of the ball spin. This indicates that auditory information contributes to identification of the magnitude of the ball spin, however, it also reveals that, in table tennis, the level of training does not interfere with the auditory perception of the ball spin. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to investigate the influence of futsal match-related fatigue on running performance, neuromuscular variables, and finishing kick speed and accuracy. Methods: Ten professional futsal players participated in the study (age: 22.2 ± 2.5 years) and initially performed an incremental protocol to determine maximum oxygen uptake (V̇O2max: 50.6 ± 4.9 mL.kg−1.min−1). Next, simulated games were performed, in four periods of 10 min during which heart rate and blood lactate concentration were monitored. The entire games were video recorded for subsequent automatic tracking. Before and immediately after the simulated game, neuromuscular function was measured by maximal isometric force of knee extension, voluntary activation using twitch interpolation technique, and electromyographic activity. Before, at half time, and immediately after the simulated game, the athletes also performed a set of finishing kicks for ball speed and accuracy measurements. Results:Total distance covered (1st half: 1986.6 ± 74.4 m; 2nd half: 1856.0 ± 129.7 m, P = 0.00) and distance covered per minute (1st half: 103.2 ± 4.4 m.min−1; 2nd half: 96.4 ± 7.5 m.min−1, P = 0.00) demonstrated significant declines during the simulated game, as well as maximal isometric force of knee extension (Before: 840.2 ± 66.2 N; After: 751.6 ± 114.3 N, P = 0.04) and voluntary activation (Before: 85.9 ± 7.5%; After: 74.1 ± 12.3%, P = 0.04), however ball speed and accuracy during the finishing kicks were not significantly affected. Conclusion: Therefore, we conclude that despite the decline in running performance and neuromuscular variables presenting an important manifestation of central fatigue, this condition apparently does not affect the speed and accuracy of finishing kicks. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the effects of a 5-week training program, consisting of repeated 30-m sprints, on two repeated sprint ability (RSA) test formats: one with one change of direction (RSA) and the other with multiple changes of direction (RSM). Thirty-six young male and female basketball players (age 16.1 ± 0.9 years), divided into two experimental groups, were tested for RSA, RSM, squat jump, counter-movement jump, and the Yo-Yo Intermittent Recovery-Level-1 (Yo-Yo IR1) test, before and after a 4-week training program and 1 week of tapering. One group performed 30-m sprints with one change of direction (RSA group, RSAG), whereas the other group performed multidirectional 30-m sprints (RSM group, RSMG). Both groups improved in all scores in the post-intervention measurements (P < 0.05), except for the fatigue index in the RSM test. However, when comparing the two groups, similar effects were found for almost all parameters of the tests applied, except for RPE in the RSA test, which had a greater decrease in the RSAG (from 8.7 to 5.9) than in the RSMG (from 8.5 to 6.6, P = 0.021). We can conclude that repeated 30-m sprints, either with one change of direction or multidirectional, induce similar physiological and performance responses in young basketball players, but have a different psycho-physiological impact. [ABSTRACT FROM AUTHOR]

We investigated the electromyographic response to synchronous indirect-localized vibration interventions in international and national table tennis players. Twenty-six male table tennis players, in a standing position, underwent firstly an upper arms maximal voluntary contraction and thereafter two different 30-s vibration interventions in random order: high acceleration load (peak acceleration = 12.8 g, frequency = 40 Hz; peak-to-peak displacement = 4.0 mm), and low acceleration load (peak acceleration = 7.2 g, frequency = 30 Hz, peak-to-peak displacement = 4.0 mm). Surface electromyography root mean square from brachioradialis, extensor digitorum, flexor carpi radialis, and flexor digitorum superficialis recorded during the two vibration interventions was normalized to the maximal voluntary contraction recording. Normalized surface electromyography root mean square was higher in international table tennis players with respect to national ones in all the interactions between muscles and vibration conditions (P < 0.05), with the exception of flexor carpi radialis (at low acceleration load, P > 0.05). The difference in normalized surface electromyography root mean square between international table tennis players and national ones increased in all the muscles with high acceleration load (P < 0.05), with the exception of flexor digitorum superficialis (P > 0.05). The muscle activation during indirect-localized vibration seems to be both skill level and muscle dependent. These results can optimize the training intervention in table tennis players when applying indirect-localized vibration to lower arm muscles. Future investigations should discriminate between middle- and long-term adaptations in response to specific vibration loads. [ABSTRACT FROM AUTHOR]

The aim of the present study was to examine the reliability of a novel multi-direction repeated sprint ability (RSA) test [RSM; 10 x (6 x 5-m)] compared with a RSA with one change of direction [10 x (2 x 15-m)], and the relationship of the RSM and RSA with Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) and jump performances [squat jump (SJ) and counter-movement-jump (CMJ)]. Thirty-six (male, n = 14, female n = 22) young basketball players (age 16.0 ± 0.9 yrs) performed the RSM, RSA, Yo-Yo IR1, SJ, and CMJ, and were re-tested only for RSM and RSA after 1 week. The absolute error of reliability (standard error of the measurement) was lower than 0.212 and 0.617-s for the time variables of the RSA and RSM test, respectively. Performance in the RSA and RSM test significantly correlated with CMJ and SJ. The best time, worst time, and total time of the RSA and RSM test were negatively correlated with Yo-Yo IR1 distance. Based on these findings, consistent with previously published studies, it was concluded that the novel RSM test was valid and reliable. [ABSTRACT FROM AUTHOR]

The article discusses research investigating the relationship between aerobic and anaerobic parameters from three-minute all-out tethered swimming and 400-meter (m) maximal front crawl effort in 30 swimmers. Topics include maximal lactate steady state (MLSS) and measures of lactate minimum (LMI), three-minute final force, which is equivalent to critical force (CF3-MIN), and peak oxygen uptake (Vo2peak).

The article discusses research of the maximal lactate steady-state (MLSS) in soccer players using anaerobic threshold (AT) determined on the soccer-specific Hoff circuit (ATHoff) to predict exercise intensity. Topics include the importance of aerobic fitness to soccer player performance, aerobic capacity evaluation for performance optimization, and the reproducibility of AT determined on the Hoff circuit in the prediction of MLSS.

PURPOSE: To analysis the effect of cycling exercise at acute severe intensity domain on modulation of metabolomic profile in human muscle tissue, as well as to report the main metabolic pathways. METHODS: Seven healthy physically active men (21±2 yrs and VO2max of 43.6±4.6 mL·kg-1·min-1) were underwent to an effort until exhaustion at severe intensity domain. Vastus lateralis muscle biopsies were performed before (at rest) and immediately after the effort for quantifying the muscle metabolites changes using ¹H-NMR spectroscopy. RESULTS: The time until exhaustion (tlim) recorded was 224.7±35.5 s, whereas the energetic contribution corresponded to 71.2±2.8% oxidative, 20.0±3.0% glycolytic and 8.8±1.3% phosphagen. The muscle pH after cycling exhaustion was 6.48±0.05. A total of 54 metabolites were identified and quantified. The most impacted pathways (impact > 0.0) included: beta oxidation of very long chain fatty acids (0.049), mitochondrial electron transport chain (0.060), alanine aspartate and glutamate metabolism (0.200), citric acid cycle (0.118), arginine biosynthesis (0.117), propanoate metabolism (0.004), threonine and 2-oxobutanoate degradation (0.143) and pyruvate metabolism (0.084). The muscle metabolite concentrations Pre and Post exercise increased for fumarate (42%, p=.025), succinate (101%, p=.021), glucose (245%, p=.001), lactate (123%, p=.004), O-acetylcarnitine (165%, p=.011), glycerol (79%, p=.040), AMP (288%, p=.008), 2-oxobutyrate (121%, p<.001) and methanol (58%, p=.034). There were decreases for creatine phosphate (-70%, p=.008), ADP (-56%, p=.007), carnitine (-33%, p=.006) and glutamate (-42%, p=.009). However, only the succinate had a significantly correlation with tlim (r=-0.76, p=.0497). In addition, the muscle pH measured at exhaustion was significantly correlated with tlim (r=-0.83; p=.042), the post-exercise succinate concentration (r=0.93; p=.006). CONCLUSIONS: Besides the classical expected contribution of glycolytic and phosphagen energetic pathways, the high-intensity exercise was associated with pathways indicatives of amino acid and fatty acid oxidation metabolisms, highlighting the inverse correlation between intramuscular succinate levels and tlim. Supported by FAPESP Grant 2018/21126-6 [ABSTRACT FROM AUTHOR]

The article discusses research which was conducted to investigate the effect hyperlactemia and blood acidosis induction had on lactate minimum intensity in cyclists. Researchers evaluated 20 recreationally trained male athletes who were experienced cyclists and underwent three lactate minimum tests while performing on an electromagnetic cycle ergometer. They found that hyperlactemia induction modes effected lactate minimum power and physiological responses in the cyclists.

An analysis of different techniques for the prediction of running performance has been widely investigated to improve athletes. The purpose of this study was to evaluate the use of laboratory tests to predict running performance. The relationship between maximal oxygen consumption (VO2 max), velocity associated with VO2 max (vVO2 max), and critical velocity (CV) with 1200, 2400, and 2800 m performances. Thirteen Brazilian Army runners performed an incremental treadmill test starting at 12 km·h-1 with increments of 1 km·h-1 every 3 min until exhaustion to determine VO2 max and vVO2 max. Later, the runners ran at 100, 110, and 120% of vVO2 max to determine CV on treadmill. In addition to the laboratory test, the subjects performed three maximal runs at 1200 (P1200), 2400 (P2400), and 2800 (P2800) m on the track. Data normality was verified using the Shapiro Wilk's and Pearson correlations (P=0.05) were used to determine the relationship between the laboratory variables and the performances field test. The results showed significant correlations for P1200, P2400, and P2800 with CV (r = -0.70) and vVO2 max (r = -0.85). Based on the results of this investigation, we conclude that CV and vVO2 max determined in the laboratory can be used to predict performance in the distances studied in military runners. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine if the use of the running-based anaerobic sprint test (RAST) could be used to predict anaerobic capacity in running athletes. Eleven male middle-distance runners (21 ± 1 yrs) volunteered to take part in this study. The maximum accumulated oxygen deficit (MAOD) was determined during running on a treadmill, and the RAST was determined during running on a track. None of the variables associated with RAST output (peak power, mean power, fatigue index, and maximal and mean velocities) was significantly correlated with MAOD. Thus, the findings indicate that the use of the RAST does not predict anaerobic capacity in running. [ABSTRACT FROM AUTHOR]

The aim of this study was to validate critical frequency specific test (critf) for the estimation of the aerobic endurance in table tennis players. Methods: Eight male international-level table tennis players participated of this study. Specific tests were applied by using a mechanical ball thrower to control the intensity of the exercise. The critf was determined by applying three or four series of exercises to exhaustion (Tlim). The critf was evaluated by using lactate steady state test (90, 100, and 106 % of critf intensity). The other specific test was an incremental protocol used to determine the anaerobic threshold (AnTBI) and the onset of blood lactate accumulation (OBLA) using a ball thrower. Results: The critf (39.87 ± 3.31 balls·min-1) was not significantly different among AnTBI (48.11 ± 7.36 balls·min-1) and OBLA3.5 (49.36 ± 12.04 balls·min-1) frequencies and it was correlated with AnTBI parameter (r = 0.78). At frequencies of the 90 and 100% of critf a dynamic equilibrium was verified in lactate concentration between the eighth and twentieth minutes. However, this dynamic equilibrium was not found at 106% intensity. Conclusion: The data indicate that in table tennis the critf model can be used for measuring the aerobic endurance. [ABSTRACT FROM AUTHOR]

The article discusses a study which verifies the applicability of anaerobic work capacity (AWC) determined from the critical power model in elite table tennis players. It demonstrates tests including the critical frequency test used to determinate the anaerobic work capacity and wingate tests performed using leg and arm ergometers. It is concluded that the AWC determined by a modified critical power test was not a good index for measurement of anaerobic capacity in table tennis players.

The purpose of this research was to examine how an 11-day taper after an 8.5-week experimental training cycle affected lactate levels during maximal exercise, mean force, and performance in training swimmers, independent of shaving, psychological changes, and postcompetition effects. Fourteen competition swimmers with shaved legs and torsos were recruited from the São Paulo Aquatic Federation. The training cycle consisted of a basic training period (endurance and quality phases) of 8.5 weeks, with 5,800 m·d-1 mean training volume and 6 d·wk-1 frequency; and a taper period (TP) of 1.5 weeks' duration that incorporated a 48% reduction in weekly volume without altering intensity. Attained swimming force (SF) and maximal performance over 200-m maximal swim (Pmax) before and after taper were measured. After taper, SF and Pmax improved 3.6 and 1.6%, respectively (p < 0.05). There were positive correlations (p < 0.05) between SF and Pmax before (r = 0.86) and after (r = 0.83) the taper phase. Peak lactate concentrations after SF were unaltered before (6.79 ± 1.2 mM) and after (7.15 ± 1.8 mM) TP. Results showed that TP improved mean swimming velocity, but not in the same proportion as force after taper, suggesting that there are other factors influencing performance in faster swimming. [ABSTRACT FROM AUTHOR]

Goalball is a Paralympic sport involving people with visual impairment. Little is known about the physical fitness of elite players of this sport, as previous studies only evaluated body composition and aerobic capacity. Thus, the aim of this study was to describe the performance of elite goalball players in different physical tests and to look for relationships between them. Eleven elite Brazilian goalball players, seven males and four females, were evaluated for body composition, maximal handgrip isometric force (MHGF), countermovement jump (CMJ), throwing velocity (TV) and the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1). Players produced 41.54 ± 8.41 kgf in MHGF, 34.81 ± 7.2 cm in CMJ, 14.21 ± 1.89 m∙s−1 in TV, and 505 ± 313 m in Yo-Yo IR1, with an estimated maximum oxygen consumption (VO2max) of 40.64 ± 2.63 mL∙kg−1∙min−1. Most performance tests exhibited moderate to high correlations among them, while the percentage of body fat correlated with both the CMJ and Yo-Yo IR1 results. The current study reveals that CMJ could be a valuable monitoring tool as it was correlated with all other performance tests. The highest correlation observed was with TV (r = 0.754; p < 0.05), which is a key capacity in goalball. Moreover, high levels of body fat could be detrimental to anaerobic performance. [ABSTRACT FROM AUTHOR]

Due to the controversy about the sensitive of lactate minimum intensity (LMI) to training and the need to develop other tool for aerobic fitness evaluation, the purpose of this study was to analyze the sensitivity of glucose minimum intensity (GMI) and LMI to endurance training. Eight trained male cyclists (21.4 ± 1.9 years, 67.6 ± 7.5 kg and 1.72 ± 0.10 m) were evaluated twice, before and after 12 weeks of training. GMI and LMI were calculated, respectively, by the lowest blood glucose and lactate values attained during an incremental test performed after a hyperlactemia induction, and VO2max was determined during standard incremental effort. The training was prescribed in three different zones and controlled by heart rate (HR). The training distribution was equivalent to 59.7%, 25.0% and 15.3% below, at and above anaerobic threshold HR respectively. The anaerobic threshold evaluated by GMI and LMI improvement 9.89 ± 4.35% and 10.28 ± 9.89 respectively, after training, but the VO2max 2.52 ± 1.81%. No differences were found between GMI and LMI in pre (218.2 ± 22.1 vs 215.0 ± 18.6 W) and post (240.6 ± 22.9 vs 237.5 ± 18.8 W) training situations. LMI and GMI were sensitive to 12-week aerobic training in cyclist; thus, both protocols can be used to assess aerobic adaptation, athletes diagnostic and prescribe training. [ABSTRACT FROM AUTHOR]