Drop jumps versus sled towing and their effects on repeated sprint ability in young basketball players.

BACKGROUND: The aim of the investigation was to compare the occurrence of post-activation performance enhancement (PAPE) after drop jumps, or heavy sled towing, and the subsequent effect on repeated sprint ability (RSA). METHODS: Ten young basketball players (17 ± 1 yrs) performed, in randomized order, RSA test with changes of direction after a standardized warm up followed by drop jumps, heavy sled towing, or no exercise (control condition). Neuromuscular assessments composed of two maximal voluntary contractions of the knee extensors, peripheral nerve stimulation, and surface electromyography (EMG), responses were recorded before and immediately after the RSA. The EMG signal of leg muscles during sprinting were also recorded as well as the blood lactate concentration. RESULTS: The drop jumps improved the RSA mean time (P = 0.033), total time (P = 0.031), and slowest time (P = 0.029) compared to control condition, while heavy sled towing did not change RSA outcomes (P > 0.05). All conditions exhibited a decrease of doublet high frequency stimulation force (pre-post measurement) (P = 0.023) and voluntary activation (P = 0.041), evidencing the occurrence from peripheral and central components of fatigue after RSA, respectively, but no difference was evident between-conditions. There was a significantly greater EMG activity during sprints for the biceps femoris after drop jumps, only when compared to control condition (P = 0.013). CONCLUSION: Repeated drop jumps were effective to induce PAPE in the form of RSA, while heavy sled towing had no effect on RSA performance in young basketball players. Furthermore, both conditioning activities exhibited similar levels of fatigue following the RSA protocol. Thus, drop jumps may be used as an alternative to induce PAPE and thus improve performance during sprints in young male basketball players.

Impacts of high-intensity exercise on the metabolomics profile of human skeletal muscle tissue.

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 1 H-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.

Full Body Photobiomodulation Therapy to Induce Faster Muscle Recovery in Water Polo Athletes: Preliminary Results.

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 46.17 mW/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.

Cycling Performance Enhancement After Drop Jumps May Be Attributed to Postactivation Potentiation and Increased Anaerobic Capacity.

de Poli, RAB, Boullosa, DA, Malta, ES, Behm, D, Lopes, VHF, Barbieri, FA, and Zagatto, AM. Cycling performance enhancement after drop jumps may be attributed to postactivation potentiation and increased anaerobic capacity. J Strength Cond Res 34(9): 2465-2475, 2020-The study aimed to investigate the effects of drop jumps (DJs) on supramaximal cycling performance, anaerobic capacity (AC), electromyography, and fatigue. Thirty-eight recreational cyclists participated into 3 independent studies. In study 1 (n = 14), neuromuscular fatigue was assessed with the twitch interpolation technique. In study 2 (n = 16), the AC and metabolic contributions were measured with the maximal accumulated oxygen deficit method and the sum of the glycolytic and phosphagen pathways. In study 3 (n = 8), postactivation potentiation (PAP) induced by repeated DJs was evaluated. The DJ protocol was effective for significantly improving cycling performance by +9.8 and +7.4% in studies 1 and 2, respectively (p ≤ 0.05). No differences were observed in electromyography between conditions (p = 0.70); however, the force evoked by a doublet at low (10 Hz) and high frequencies (100 Hz) declined for control (-16.4 and -23.9%) and DJ protocols (-18.6 and -26.9%) (p < 0.01). Force decline was greater in the DJ condition (p < 0.03). Anaerobic capacity and glycolytic pathway contributions were +7.7 and +9.1% higher after DJ protocol (p = 0.01). Peak force during maximal voluntary contraction (+5.6%) and doublet evoked force at 100 Hz (+5.0%) were higher after DJs. The DJ protocol induced PAP, improved supramaximal cycling performance, and increased AC despite higher peripheral fatigue.

Metabolic Profile and Performance Responses During Two Consecutive Sessions of Sprint Interval Training.

Malta, ES, Brisola, GMP, de Poli, RAB, Dutra, YM, Franchini, E, and Zagatto, AM. Metabolic profile and performance responses during two consecutive sessions of sprint interval training. J Strength Cond Res 34(4): 1078-1085, 2020-The study aimed to (a) typify the cardiorespiratory, metabolic, and performance responses during a single sprint interval training (SIT) session, (b) investigate the interference of 2 subsequent sessions on cardiorespiratory, metabolic, and performance responses, and (c) verify the relationships of SIT total work performed with aerobic fitness indices. Thirty-six untrained men performed 2 SIT sessions (SIT1 and SIT2) separated by 24 hours of recovery. Each session was composed of 4 Wingate bouts interspersed by 4 minutes. Within SIT sessions, bout work, peak power, and mean power of each Wingate bout decreased significantly, while the fatigue index increased over time (p < 0.001). The SIT elicited lower acute responses of oxygen uptake and heart rate than maximal values (≈67 and ≈79%, respectively) (p < 0.05) as well as a short time spent at high cardiorespiratory demand. For SIT outcomes, no interactions were verified between Wingate bout performance, average heart rate, and average oxygen uptake. In addition, the oxygen uptake integral (SIT1:300.5 ± 38.6 ml·kg; SIT2:306.9 ± 41.1 ml·kg) and total work (SIT1:54.6 ± 10.4 kJ; SIT2:54.9 ± 10.6 kJ) did not differ between SIT sessions (p > 0.05). Furthermore, significant moderate to strong correlations were found between SIT1 and SIT2 total work and peak oxygen uptake (r = 0.48; r = 0.52, respectively), maximal aerobic power (r = 0.89; r = 0.89, respectively), and respiratory compensation point (r = 0.80; r = 0.78, respectively). In summary, an SIT session elicited a short time spent at high cardiorespiratory demand, while the SIT total work was significantly correlated with aerobic fitness indices. In addition, 2 consecutive SIT sessions interspaced by 24 hours did not affect performance outcomes, or cardiorespiratory and blood responses.

Effects of Seasonal Training Load on Performance and Illness Symptoms in Water Polo.

Brisola, GMP, Claus, GM, Dutra, YM, Malta, ES, de Poli, RAB, Esco, MR, and Zagatto, AM. Effects of seasonal training load on performance and illness symptoms in water polo. J Strength Cond Res 34(2): 406-413, 2020-The purpose of the study was to describe the training load distribution of a young female water polo team in different cycles of the season and verify its subsequent effects on specific fitness measured by the repeated sprints ability (RSA) test, aerobic endurance measured by the lactate minimum test, incidence and severity of upper respiratory tract infection (URTI) symptoms, and muscle damage markers. The training load (i.e., rating of perceived exertion × session duration) of 20 young female water polo players (mean ± SD: age = 15.65 ± 1.3 years; body mass = 60.93 ± 11.0 kg; height = 1.62 ± 0.1 m) was monitored, and the incidence and severity of URTI was assessed during part of the season. In addition, we assessed the lactate minimum speed (LMS), RSA, creatine kinase (CK), and lactate dehydrogenase (LDH) blood concentration during the season. The level of significance set was p < 0.05. The training loads were higher in the specific period (p < 0.01), whereas a high incidence of URTI was observed in the general cycle. The LMS was greater in the general cycle (p < 0.05), whereas total time and best time in the RSA test were greater in the competitive cycle (p < 0.05). The CK and LDH concentrations were significantly lower during the competitive cycle (p < 0.01). The general cycle of a female water polo team is critical regarding URTI and muscle damage, even with smaller training loads than the specific period.

Effects of Caffeine Ingestion on Anaerobic Capacity in a Single Supramaximal Cycling Test.

The aim of this study was to verify the effects of caffeine on anaerobic capacity estimated by the sum of the estimated glycolytic [E[La]] and phosphagen [EPCr] metabolism based on blood lactate and excess post-oxygen consumption responses (AC[La-]+EPOCfast). Fourteen male cyclists were submitted to a graded exercise test to determine the maximal oxygen uptake ( V ° O 2 m a x ) and intensity associated with   V ° O 2 m a x (i V ° O 2 m a x ). Subsequently, the participants performed two supramaximal efforts at 115% of i V ° O 2 m a x to determine the AC[La-]+EPOCfast, after previous supplementation with caffeine (6 mg·kg-1) or a placebo (dextrose), in a cross over, randomized, double blind, and placebo-controlled design. The time to exhaustion was higher in the caffeine (186.6 ± 29.8 s) than in the placebo condition (173.3 ± 25.3 s) (p = 0.006) and a significant correlation was found between them (r = 0.86; P = 0.00008). Significant differences were not found between AC[La-]+EPOCfast values from the placebo (4.06 ± 0.83 L and 55.2 ± 5.7 mL·kg-1) and caffeine condition (4.00 ± 0.76 L and 54.6 ± 5.4 mL·kg-1); however, a significant correlation was observed only for AC[La-]+EPOCfast expressed in absolute values (r = 0.74; p < 0.002). The E[La] and EPCr also presented no significant differences and they were significantly correlated (r = 0.82 and r = 0.55, respectively; p < 0.05). We conclude based on the overall comparison of mean values between two treatments that acute caffeine ingestion improves the time to exhaustion but does not affect anaerobic capacity estimation.

The sensitivity of the alternative maximal accumulated oxygen deficit method to discriminate training status.

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.