Beetroot juice ingestion does not improve neuromuscular performance and match-play demands in elite female hockey players: a randomized, double-blind, placebo-controlled study.

PURPOSE: Beetroot juice is a dietary supplement that contains high levels of inorganic nitrate (NO3-) and that its intake has proven effective at increasing blood nitric oxide (NO) concentrations improving endurance performance. However, the effect of this supplement in team sport performance, especially in female athletes, has been barely studied. This study aimed to compare the acute effects of beetroot juice supplementation on neuromuscular performance and match-play demands in elite female field hockey players. METHODS: Eleven elite female hockey players (22.8 ± 5.1 years) belonging to a bronze team medal in Eurohockey Club Champions Cup participated in this study. Participants were randomly divided into two groups undergoing a test battery with beetroot juice (70 mL, 6.4 mmol NO3-) or placebo (70 mL, 0.04 mmol NO3-) in two different days with one week between protocols. The neuromuscular test battery consisted of a countermovement jump, isometric handgrip strength (i.e., dominant hand), 20 m-sprint and repeated sprint ability test (RSA). Afterward, a simulated hockey match play (2 × 12.5 min) was performed and recorded by Global Positioning System (GPS). RESULTS: No statistically significant improvements were observed in any physical parameters analysed comparing beetroot juice compared to placebo ingestion, countermovement jump (p = 0.776, ES = 0.16), isometric handgrip strength (p = 0.829; ES = - 0.08), 20 m sprint test (p = 0.227; ES = - 0.23), mean repeated sprint ability (p = 0.955, ES = 0.03) and in any physical match demands measured by GPS (p = 0.243-1.000; ES = 0.02-0.47). CONCLUSION: Acute beetroot juice supplementation did not produce any statistically significant improvement in neuromuscular performance or match-play demands in elite female field hockey players. TRIAL REGISTRATION: The study was registered in ClinicalTrials.gov with the following ID: NCT05209139. The study was retrospectively registered by 26 January 2022.

Effects of Six Weeks of Flywheel Single-Leg Romanian Deadlift Training on Speed, Jumping and Change of Direction Performance.

Several studies have confirmed the efficacy of flywheel training, mainly in the bilateral half-squat exercise. The aim of the present study was to analyze the effects of single-leg Romanian deadlift flywheel training on speed, jumping and change of direction performance. Seventeen young healthy males underwent two periods of 3-week training based on two weekly sessions of 3 sets × 7 repetitions or 4 sets × 7 repetitions of single-leg Romanian deadlifts (0.037 kg/m² moment inertia) with their dominant and non-dominant leg. After the first three weeks of the program, the CMJ, the 10 m, 30 m and total sprint times, as well as the COD-90 test, presented likely substantial beneficial effects and a small decrease in the relationship between the sprint and COD-90 test performance. After the second period of the three-week training, likely detrimental effects were observed in some of the change of direction conditions and an increase in the relationship between the sprint and the COD-180 performance. It could be hypothesized that most of the flywheel training effects reported in the traditional protocols lasting a minimum of 5-6 weeks would occur in the first weeks of training.

Case Studies in Physiology: Training adaptation in an elite athlete after breast cancer diagnosis.

The aim of this study was to evaluate the capacity to return to competition of a 28-yr-old female 400-m hurdle elite athlete after a diagnosis of breast cancer. The study lasted 14 mo after diagnosis. She was tested four times (T1-T4) to measure body mass (BM), body mass index (BMI), percentage of total fat mass (TFM%), total fat-free mass (TFFM%), bone mineral density (BMD), one-repetition maximum (1RM), and maximal power (MP) in bench press and half squat, maximum oxygen uptake, and 400-m dash and hurdles. T0 (baseline time) was established with values before diagnosis. BM and BMI increased from T0 to T1 (5.3% and 5.2%) and remained stable. BMD experienced no change. TFM% values decreased from T1 to T4 (3.5%). TFFM% values increased from T1 to T3 (0.9%). During T1-T2, the athlete presented a global decline from T0 in 1RMSquat, 1RMBench, MPSquat, and MPBench (32.6%, 27.2%, 37.5%, and 27.6%, respectively). Results during T3-T4 were also lower for these parameters from T0 (23.3%, 20.6%, 23.4%, and 11%). During T1-T2, the V̇o2max declined compared with T0 (1.8% and 6.4%), showing a small increase at T3 (+1%) and reaching the lowest level at T4 (9%). During T1-T2, the time record of 400-m dash (8.3%) and hurdles (7.4%) increased. However, a slight improvement was found at T3 (1.3% and 0.6%, respectively). The results of this case study reflect that exercise training improved body composition, maintained BMD and TFFM, but could not completely reverse the worsening of the cardiorespiratory, muscle strength and power, and running performance levels.NEW & NOTEWORTHY This case study follows an elite athlete and measures her performance during cancer treatment. It improves the knowledge on applied physiology showing the details of her training program and demonstrating the strong ability of the athlete to continue training and competing at a high level during antineoplastic treatment. Exercise training improved body composition but failed to restore previous cardiorespiratory, muscle strength and power, and running performance levels.

Relationships between Strength and Step Frequency with Fatigue Index in Repeated Sprint Ability.

Force-velocity profile (FVP) and repeated-sprint ability (RSA) tests are indicators of physical capacities in most team sport players. The purpose of this study was to examine the stride kinematics during a repeated-sprint ability (RSA) test and to analyze the relationship between Bosco's force-velocity profile (FVP) and RSA performance in elite female field hockey players. Thirteen elite-female players performed both RSA (six 30 m maximal sprints) and jumping (CMJ weighted and body weight) tests. Sprinting time fatigue indexes during a 30 m RSA test were correlated with step frequency fatigue indexes (r > 0.7; p < 0.01). CMJ50 showed a large relationship with sprint time fatigue indexes. FV50 showed a very large relationship with sprint time fatigue indexes (r > 0.7; p < 0.01), and a large relationship with the step frequency fatigue indexes (r > 0.5; p < 0.05). This study highlighted two possible ways to improve fatigue indexes in RSA, with the aim of maximizing the distances covered at high-intensities during the matches: (a) strength training and (b) focusing on step frequency during speed training.

Effects of Caffeine Ingestion on Physical Performance in Elite Women Handball Players: A Randomized, Controlled Study.

PURPOSE: To investigate the effects of acute caffeine (CAFF) intake on physical performance in elite women handball players. METHODS: A total of 15 elite women handball players participated in a randomized, double-blind study. In 2 different trials, participants ingested either a placebo (cellulose) or 3 mg of CAFF per kilogram of body mass (mg/kg bm) before undergoing a battery of neuromuscular tests consisting of handball throws, an isometric handgrip strength test, a countermovement jump, a 30-m sprint test (SV) and a modified version of the agility T test. Then, participants performed a simulated handball game (2 × 20 min), and movement patterns were recorded with a local positioning system. RESULTS: Compared with the placebo, CAFF increased ball velocity in all ball throws (P = .021-.044; effect size [ES] = 0.39-0.49), strength in isometric handgrip strength test (350.8 [41.2] vs 361.6 [46.1] N, P = .034; ES = 0.35), and countermovement-jump height (28.5 [5.5] vs 29.8 [5.5] cm; P = .006; ES = 0.22). In addition, CAFF decreased running time in the SV (4.9 [0.2] vs 4.8 [0.3] s; P = .042; ES = -0.34). In the simulated game, CAFF increased the frequency of accelerations (18.1 [1.2] vs 18.8 [1.0] number/min; P = .044; ES = 0.54), decelerations (18.0 [1.2] vs 18.7 [1.0] number/min; P = .032; ES = 0.56), and body impacts (20 [8] vs 22 [10] impacts/min; P = .032; ES = 0.30). However, postexercise surveys about self-reported feelings of performance indicate that players did not feel increased performance with CAFF. CONCLUSION: Preexercise ingestion of 3 mg/kg bm of CAFF improved ball-throwing velocity, jump, and sprint performance and the frequency of in-game accelerations and decelerations in elite women handball players.

Spatiotemporal Comparisons Between Elite and High-Level 60 m Hurdlers.

Despite the existence of literature on the athletics hurdles event, no previous studies have examined the kinematic behavior of athletes during the race. The aims of the present research were (1) to compare the spatiotemporal parameters of elite and high-level hurdlers (men and women) in the approach run, hurdles-unit and run-in phases and (2) to relate these parameters to the 60 m end race results. Split times, step lengths, step widths, step times, contact times and flight times were calculated for the 60 m hurdlers (n = 110) who participated in the 44th Spanish Indoor Championship and in the 12th IAAF World Indoor Championship. Both men and women elite-level hurdlers obtained shorter split times than high-level hurdlers in the approach run (δ 0.14 ± 0.01 and 0.18 ± 0.02 s, respectively), the hurdles-unit (δ 0.11 ± 0.01 and 0.13 ± 0.01 s, respectively) and the run-in (δ 0.10 ± 0.01 and 0.20 ± 0.02 s, respectively) race phases. Elite-level men athletes also presented lower step lengths in the approach run phase (δ 0.01 ± 0.00 m), greater take-off distances (δ 0.10 ± 0.03 m) and shorter landing distances (δ 0.17 ± 0.05 m) than high-level athletes, although elite-level women hurdlers only showed longer landing step length (δ 0.07 ± 0.02 m) than high-level athletes. Finally, in the run-in phase, elite-level hurdlers had longer step lengths than high-level hurdlers (men: δ 0.09 ± 0.03 m; women: δ 0.11 ± 0.03 m). Step times, contact times and flight times were also different between both levels of performance in most of the race phases. Correlational analysis with the race result showed large (r > 0.5), very large (r > 0.7), or nearly perfect (r > 0.9) relationships for most of the mentioned kinematic parameters. These results indicate that elite-level athletes were faster than high-level in the three phases of the 60 m hurdles event, specifically in some new spatiotemporal parameters (e.g. step length in the run-in phase) as well as others already studied. Accordingly, coaches and athletes should implement their training programs to have an impact on these key variables.

Race Strategies of Open Water Swimmers in the 5-km, 10-km, and 25-km Races of the 2017 FINA World Swimming Championships.

Despite literature on the pacing strategies of endurance sports, there is an existing lack of knowledge about the swimmers' tactical decisions in the open water races. The aims of the present research were (1) to compare the pacing profiles and tactical strategies of successful elite open water swimmers (men and women) in the 5-km, 10-km, and 25-km races and (2) to relate these pacing strategies to the end race results. Intermediate split times, positions and gaps with leaders of the first ten swimmers classified in the 2017 FINA World Swimming Championships races were collected from the public domain and were related to the finishing positions. Overall swimming velocities of the 5-km races were faster than the 10-km (δ 0.03 ± 0.03 m/s) and the 25-km (δ 0.14 ± 0.01 m/s) events with male swimmers achieving relatively faster mean velocities than females in the 5-km (δ 0.12 ± 0.01 m/s) compared to the 25-km (δ 0.08 ± 0.01 m/s) events. Medallist swimmers achieved moderate faster overall velocities than finalists in the 25-km races (0.01 ± 0.01 m/s) only. Inter-level differences were detected in selected splits for each race distance. Pacing profiles presented lap to lap velocity improvements in the 5-km and men's 10-km races (from +0.02 ± 0.00 to +0.11 ± 0.01 m/s) but also mid-race decreases in the women's 10-km and on the 25-km races. Successful swimmers were located in the leading positions of the 5-km races but at mid-group in the first part of the 10-km and 25-km races, with time gaps with leaders of 15-20 s. Faster lap swimming velocities, mid-race leading positions and shorter time-gaps were only related to the finishing positions in the last lap of the 10-km and in the three last laps of the 25-km events, but also in the first lap of the women's 5-km race. Despite different mid-race positioning, successful open water swimmers typically presented negative pacing profiles, a consistent control of mid-race gaps with leaders (15-20 s maximum) and great spurts (4-6% faster than mean race velocities) at the end of races. Coaches and swimmers should be aware of the different race dynamics depending to the event distance in order to select optimal race strategies.

Acute effects of a single tennis match on passive shoulder rotation range of motion, isometric strength and serve speed in professional tennis players.

Shoulder pain has been associated with glenohumeral internal rotation deficit (GIRD) and a reduction in external rotation (ER) strength; however, in tennis players, there is scarce evidence regarding the impact of a single match on shoulder range of motion (ROM), strength and serve speed. The aim of this study was to determine the acute effect of a single tennis match on shoulder rotation ROM, isometric strength and serve speed. Twenty-six professional tennis players participated in the study (20.4±4.4 years; 10.5±3.2 years tennis expertise; 20.5±5.4 h/week training). Passive shoulder external (ER-ROM) and internal rotation ROM (IR-ROM), ER and IR isometric strength were measured before and after a single tennis match (80.3±21.3 min) in both shoulder´s. Moreover, the total arc of motion (TAM) and ER/IR strength ratio were calculated. Video analysis was used to assess the number of serves and groundstrokes, while a radar gun was utilized to measure maximal ball speed. In the dominant shoulder, compared to pre-match levels, IR-ROM was significantly reduced (-1.3%; p = 0.042), while ER-ROM (5.3%; p = 0.037) and TAM (3.1%; p = 0.050) were significantly increased. In the non-dominant shoulder, ER-ROM (3.7%; p = 0.006) was increased. Furthermore, in the dominant shoulder, the isometric ER strength was significantly reduced after the match (-4.8%; p = 0.012), whereas serve speed was not significantly reduced after match (-1.16%; p = 0.197). A single tennis match leads to significant reductions in shoulder ROM (e.g., IR of the dominant shoulder) and isometric strength (e.g., ER of the dominant shoulder). This study reveals the importance of recovery strategies prescription aiming at minimize post-match alteration in the shoulders.