European Journal of Sport Science最新文献

Capsinoids may exert ergogenic effects on resistance exercises. However, the acute effects of capsinoids on neuromuscular performance in humans are unknown. Here, we aimed to investigate the acute effects of dihydrocapsiate on lower- and upper-body neuromuscular performance parameters in resistance-trained individuals. 25 young adults (n = 6 women; age = 26 ± 3 years; body mass index = 24.3 ± 2.8 kg/m²) with ≥ 1-year resistance training experience were included in this triple-blind (participants, intervention researchers, and data analysts were blinded), placebo-controlled, crossover study. Lower- and upper-body ballistic strength (countermovement jump [CMJ] height and bench press throw [BPT] peak velocity), maximum dynamic strength (estimated 1 repetition maximum in squat and bench press [BP]), and strength-endurance (mean set velocity [squat] and number of repetitions to failure [bench press]) were assessed in 2 independent sessions (≥7 days separation). Participants ingested 12 mg of dihydrocapsiate or placebo 30 min before each trial. We found no significant differences between dihydrocapsiate and placebo conditions in ballistic strength, (CMJ height 33.20 ± 8.07 vs 33.32 ± 7.85 cm; BPT peak velocity 2.82 ± 0.77 vs 2.82 ± 0.74 m/s) maximal dynamic strength (estimated squat 1RM: 123.76 ± 40.63 vs 122.66 ± 40.97 kg; estimated BP 1RM: 99.47 ± 43.09 vs 99.60 ± 43.34 kg), and strength-endurance (squat mean set velocity 0.66 ± 0.07 vs 0.66 ± 0.05 m/s; number BP repetitions to failure 13.00 ± 3.56 vs 13.00 ± 4.78) (all P ≥ 0.703). We conclude that dihydrocapsiate does not acutely improve neuromuscular performance in trained young adults.

We aimed to investigate the impact of pistachio nut consumption on muscle soreness and function following exercise-induced muscle damage. Using a randomised cross-over design, male team-sport players (n = 18) performed a 40-minute downhill treadmill run to induce muscle damage, which was conducted after 2-wks of consuming either control (CON, water), a standard dose of daily pistachios (STD, 42.5 g/d) or a higher dose of daily pistachios (HIGH, 85 g/d). Lower limb muscle soreness (visual analogue scale), muscle function (maximal voluntary isokinetic torque and vertical jump), and blood markers of muscle damage/inflammation (creatine kinase, C-reactive protein, myoglobin, superoxide dismutase) were measured pre (baseline) and post (24, 48, and 72 h) exercise. No trial order effects were observed for any outcome measurement across trials. Mean quadriceps soreness (non-dominant leg) during exercise recovery was reduced (p < 0.05) in HIGH vs. CON (mean difference (95%CI): 13(1-25) mm). Change in soreness in the dominant quadriceps was not different between HIGH vs. CON (p = 0.06; mean difference (95%CI): 13(-1 to 26 mm)). No main effects of time or trial were observed for mean soreness of hamstrings, or on isokinetic torque of knee extensors or knee flexors, during recovery. Serum creatine kinase concentration peaked at 24 h post-damage (mean(SEM): 763(158)µg/L) from baseline (300(87)µg/L), but had returned to baseline by 72 h post (398(80)µg/L) exercise in all trials, with no trial or trial × time interaction evident. These data suggest that high dose pistachio nut ingestion may provide some alleviation of muscle soreness, but no effect on muscle function, following modest muscle damage.

Aerobic metabolism dominates Olympic rowing, but research on the relative contribution of strength and power demands is limited. This study aimed to identify the contribution of different strength determinants for distinct phases of rowing ergometer performance. The cross-sectional analysis comprised of 14 rowing athletes (4 female, 10 male, age: 18.8 ± 3.0y, 16.9 ± 2.2y). Measurements included anthropometrics, maximal strength of leg press, trunk extension and flexion, mid-thigh pull (MTP) and handgrip strength, VO₂max, and a 2000 m time trial, where peak forces at the start, middle and end phase were assessed. Additionally, rate of force development (RFD) was assessed during the isometric leg press and MTP with intervals of 150, 350 ms and 150, 300 ms, respectively. Stepwise regression models for ergometer performance showed that the start phase was mainly explained by maximal trunk extension and RFD 300 ms of MTP (R²= 0.91, p < 0.001) and the middle section by VO₂max, maximal leg press strength and sitting height (R²= 0.84, p < 0.001). For the end phase, a best fit was observed for trunk flexion, RFD 350 ms of leg press, body height and sex (R²= 0.97 p < 0.001), whereas absolute VO₂max, trunk flexion and sex explained variance over the entire 2000 m time trial (R²= 0.98, p < 0.001). It appears that for the high acceleration in the start phase, force transmission through maximum strength for trunk extension is essential, while fast power production along the kinetic chain is also relevant. Additionally, the results support that maximal force complements the reliance on VO₂max. Further intervention studies are needed to refine training recommendations.

ABSTRACTThe purpose of this study was to investigate the effect of a supplementation with specific collagen peptides (SCP) combined with resistance training (RT) on changes in structural properties of the patellar tendon. Furthermore, tendon stiffness as well as maximal voluntary knee extension strength and cross-sectional area (CSA) of the rectus femoris muscle were assessed. In a randomized, placebo-controlled study, 50 healthy, moderately active male participants completed a 14-week resistance training program with three weekly sessions (70-85% of 1 repetition maximum [1RM]) for the knee extensors. While the SCP group received 5g of specific collagen peptides daily, the other group received the same amount of a placebo (PLA) supplement. The SCP supplementation led to a significant greater (p < 0.05) increase in patellar tendon CSA compared with the PLA group at 60% and 70% of the patellar tendon length starting from the proximal insertion. Both groups increased tendon stiffness (p < 0.01), muscle CSA (p < 0.05) and muscular strength (p < 0.001) throughout the intervention without significant differences between the groups. The current study shows that in healthy, moderately active men, supplementation of SCP in combination with RT leads to greater increase in patellar tendon CSA than RT alone. Since underlying mechanisms of tendon hypertrophy are currently unknown, further studies should investigate potential mechanisms causing the increased morphology adaptions following SCP supplementation.Trial registration: German Clinical Trials Register identifier: DRKS00029244..

The aims of this study were to examine the effects of eight weeks of individualised force-velocity imbalance (F-Vimb) training on physical performance in basketball players and to analyse the differences in physical performance between two periods of time (four to eight weeks) with this training. Thirty male players (age, 22.8 ± 5.68 years; height, 1.87 ± 0.07 m; body mass, 86.3 ± 11.1 kg) were divided into an intervention group (INT, n = 15), who performed an individualised training based on individual F-Vimb; and a control group (CON, n = 15), who underwent a non-individualised training programme; both groups performed two days/week of intervention and the same pre-season basketball training. At baseline, at four weeks, and at eight weeks of intervention, an assessment was performed including countermovement-jumps, unilateral drop jumps, triple hop test, force-velocity profile, sprint and change of direction (COD). At four weeks, the INT showed improvements in sprint and vertical jumping actions (≥3.76%, ES ≥0.44, p ≤ 0.02). At eight weeks, the INT continued to improve vertical jumping actions (p < 0.05) and showed improvements in horizontal jumping (6.80%, ES = 0.45, p < 0.01) and COD (≥2.99%, ES ≥0.96, p < 0.01). A significant reduction in F-Vimb was observed for INT (ES = 0.77, p = 0.01). In contrast, none of these changes were observed in CON. Thus, an individualised F-Vimb training intervention improved physical performance after eight weeks, with changes in sprint and vertical jump after first four weeks. Basketball coaches should optimise the force-velocity profile and improve the performance in sport-related actions as jumping and changing direction.

Time of flight (ToF) is an objective scoring component of elite trampolining, assessed in training by maximal jump tests. The aim of this study was to assess the relationship between physical floor based performance meaures and 20-maximum ToF. Thirty-two elite level gymnasts (13 senior; 19 junior) performed a battery of floor based tests and a 20-maximum jump test. Floor based tests included cycling peak power output, reactive strength index (RSI), unloaded countermovement jumps (CMJ), and loaded CMJ's to construct a load-velocity profile for prediction of theoretical maximum force (CMJ F₀). Very large and large, positive bivariate relationships were observed between CMJ F₀ and ToF for the seniors (r = 0.85) and juniors (r = 0.56), respectively. Very large, positive bivariate relationships were observed between CMJ height and total ToF for both seniors (r = 0.74) and juniors (r = 0.77). Step-wise multiple regression analyses revealed CMJ F₀ predicted 72% of ToF variability between seniors, and CMJ height (59%), 10 to 5 RSI (13%), and CMJ F₀ (10%) predicting 82% of ToF variability between juniors. This suggests CMJ F_0, lower limb maximal isometric capabilities, and CMJ height are important floor based predictors of maximal ToF in elite gymnasts.

The importance of both general and sport-specific perceptual-cognitive abilities in soccer players has been investigated in several studies. Although these perceptual-cognitive skills could contribute significantly to soccer players' expertise, the underlying cortical mechanisms have not been clarified yet. Examining activity changes in the prefrontal cortex under different cognitive demands may help to better understand the underlying mechanisms of sports expertise. The aim of this study was to analyse the prefrontal activity of soccer experts during general and sport-specific cognitive tasks. For this purpose, 39 semi-professional soccer players performed four perceptual-cognitive tests, two of which assessed general cognition, the other two assessed sport-specific cognition. Since soccer is a movement-intensive sport, two tests were performed in motion. While performing cognitive tests, prefrontal activity was recorded using functional near-infrared spectroscopy (fNIRS) (NIRSport, NIRx Medical Technologies, USA). Differences of prefrontal activity in general and sport-specific cognitive tasks were analysed using paired t-tests. The results showed significant increases in prefrontal activity during general cognitive tests (novel stimuli) compared to sport-specific tests (familiar stimuli). The comparatively lower prefrontal activity change during sport-specific cognition might be due to learned automatisms of experts in this field. These results seem in line with previous findings on novel and automated cognition, "repetition suppression theory" and "neural efficiency theory". Furthermore, the different cortical processes could be caused by altered prefrontal structures of experts and might represent a decisive factor for expertise in team sports. However, further research is needed to clarify the prefrontal involvement on expertise in general and sport-specific cognition.

ABSTRACTPurpose: Since the effect of dietary nitrate (NO₃^-) supplementation on rugby performance is unclear, the aim of the present study was to determine the effect of acute NO₃^- supplementation, on the modified Yo-Yo intermittent recovery level 1 (IR1) performance test in trained male rugby players.Methods: In a randomised, counterbalanced, double-blind, placebo-controlled crossover design, 12 trained rugby union players performed two experimental trials three hours after supplementation of either 140 mL NO₃^--rich (BRJ; ∼12.8 mmol NO₃^-) or NO₃^--depleted (PLA) BRJ. After blood sampling, players performed the modified Yo-Yo IR1 test. Countermovement jumps (CMJ) were also measured before (pre-CMJ) and after (post-CMJ) the prone Yo-Yo IR1 test.Results: Plasma NO₃^- (BRJ: 570 ± 146 µM vs. PLA: 72 ± 23 µM) and nitrite (NO₂^-) concentrations (BRJ: 320 ± 123 nM vs. PLA: 103 ± 57 nM) were increased after BRJ compared to PLA supplementation (both P < 0.001). Performance in the modified Yo-Yo IR1 test did not differ between BRJ (542 ± 209 m) and PLA (498 ± 185 m, P = 0.3). The jump height in pre-CMJ and in post-CMJ were similar between trials (both P > 0.05).Conclusions: Acute BRJ supplementation increased plasma NO₃^- and NO₂^- concentrations but had no benefit on an intermittent running test that reflects the demands of rugby performance, and CMJ performances. The findings do not support acute high-dose NO₃^- supplementation as an ergogenic aid to enhance physical performance in trained male rugby players.

ABSTRACTThe effectiveness of a morning versus evening oral iron supplement strategy to increase iron stores was explored. Ballet and contemporary dancers with serum ferritin (sFer) < 50μg/L (n = 14), were supplemented daily with 105 mg elemental oral iron in either the morning (Fe_AM) or evening (Fe_PM) for 8 weeks. A control group (n = 6) with sFer >50μg/L were given no supplement over the same period. Dancers' sFer were measured at baseline and post-intervention. Assessment of daily training load, dietary intake, and menstruation were made. A significant interaction (p < 0.001) showed the within group sFer change over the 8-week intervention in Fe_AM (+25.9 ± 10.5μg/L) and Fe_PM, (+22.3 ± 13.6μg/L) was significantly different to CON (-30.17 ± 28.7μg/L; both p = 0.001). This change was not different between Fe_AM and Fe_PM (p = 0.778). sFer levels within Fe_AM and Fe_PM significantly increased over the 8-weeks; however, they significantly decreased in the CON group (all p < 0.05). Post-intervention sFer levels were no longer different between the three groups (p > 0.05). Training load, dietary intake, and number of menstrual cycles incurred were similar between Fe_AM and Fe_PM (p > 0.05). Oral iron supplementation in either the morning or evening appears equally effective in increasing sFer levels in dancers with sub-optimal iron status.