Biology of Sport最新文献

This study investigated the acute effects of beetroot juice (BJ) and creatine (CR) supplementation on maximal strength, heart rate variability (HRV), and muscle oxygenation during incremental resistance exercise. Eleven physically active males (age = 21.36 ± 1.8 years) completed a randomized, double-blind, placebocontrolled, crossover protocol. Participants ingested either 0.3 g · kg^-1 of CR or 15 g of beetroot powder (7.26 mmol · L^-1 or 450 mg of nitrate) two hours before each session. The three testing sessions included bench press and back squat at 60%, 70%, and 80% of one-repetition maximum (1-RM) until failure. Repetition-tofailure, peak velocity, power, Heart rate, and muscle oxygen saturation (SmO₂) were recorded during both exercises. HRV indices, lower-limb strength performance, blood lactate, and rating of perceived exertion (RPE) were measured pre- and post-session. As intensity increased, maximum repetitions decreased significantly in all exercises and conditions (p < 0.05). Both BJ and CR improved peak velocity compared to placebo (p < 0.05). BJ led to lower peak heart rates at all intensities during BP and only at 80% of 1-RM during BS and higher SmO₂ across all intensities (p < 0.05) compared to PLA and CR. From pre- to post-session, lactate and RPE increased (p < 0.05) and lower -limb strength performance and HRV declined (p < 0.05), in all conditions, with no significant differences between BJ and CR. Compared to PLA, BJ showed significantly higher Root mean square of successive differences (RMSSD), Standard deviation of normal-to-normal intervals (SDNN), and high frequency (HF) power at both pre- and post-session (p < 0.05). CR supplementation resulted in significantly higher RMSSD values compared to PLA at both pre- and post-session time points (p < 0.001), while HF was significantly elevated only at post-session (p = 0.018), and SDNN showed no significant differences at either time point. Additionally, BJ revealed significantly higher RMSSD than CR at pre-session (p = 0.041). In conclusion, both BJ and CR significantly enhanced peak velocity during incremental resistance exercises compared to placebo. However, BJ provided additional benefits in muscle oxygenation and autonomic nervous system regulation, particularly during high-intensity efforts.

Neuromuscular function is impaired following unaccustomed eccentric exercise, the repeated bout effect (RBE) however, protects from damage following a subsequent bout. Muscle damage may be mitigated in females due to protective effects of estradiol. The purpose of this study was to investigate the relationship between the follicular phase of the menstrual cycle and oral contraceptive use on neuromuscular impairments following damaging eccentric exercise and the magnitude of the RBE. Fifteen female participants (18-30 years) performed two bouts of 150 maximal eccentric contractions of the elbow flexors four weeks apart. Normally menstruating females were tested during the late follicular phase (day:10-14) of their menstrual cycle, when estradiol is near peak. Oral contraceptive users were tested on their placebo pill days (lower estradiol). Neuromuscular function following Bout1 and Bout2 (4 weeks later), was assessed using both voluntary (maximal voluntary contraction torque; MVC, voluntary activation; VA), and electrically evoked contractions (peak twitch torque, 10 Hz and 100 Hz torque). For both groups, following Bout1, there was a 16% decrease in MVC torque (p < 0.05), and soreness increased ~20-fold (p < 0.05). Following Bout 2, both groups recovered to baseline values by 48 hrs for MVC torque, and the magnitude of the RBE was similar between groups (p > 0.05). Females in the late follicular phase (classified as high estradiol) and females on combined oral contraceptives (low estradiol) had similar impairments in neuromuscular function following the first bout of eccentric exercise, and a similar RBE.

The aim of this study was to analyse the differences in physical fitness between professional players according to their playing position (left or right side) and gender. Thirty players, 15 men and 15 women, were distributed in two groups: players playing on the right side (men n = 7; women n = 7) and the players playing on the left side (men n = 8; women n = 8). All players were assessed using a battery of anthropometric and physical performance tests, including measurements of body composition, maximal strength, aerobic capacity, speed and agility. The results showed significant differences in parameters such as weight, height and maximum strength according to playing position in male padel. Players on the left side showed higher muscle mass and strength values (one repetition maximum) in specific exercises (squat and leg curl), while those on the right side showed better results in vertical jump tests (countermovement jump and squat jump). In female players, moderate differences were observed in VO_2max and hand grip strength (dominant and no dominant hand), with higher values in left-side players. These results highlighted specific physical demands associated with the technical-tactical functions of each playing position. These findings provide key information to design specific training programs to optimize performance according to the player's role on the court.

There is increasing interest in the area of brain doping among athletes. The term 'brain doping' refers to enhancing mental performance through the non-medical use of specific pharmacological substances, such as drugs and medicines. Despite hundreds of studies, it is challenging to specify well-defined and described substances that could contribute to improving cognitive abilities in sports. Therefore, we systematically reviewed existing scientific literature to identify 'brain doping' substances with proven beneficial effects on sports performance. Only 9 research studies, consisting of 7 interventional and 2 case studies, have investigated the current knowledge on substances that have or may affect the brain at the cognitive level in the context of sports. Simultaneously, we reviewed the Polish dietary supplement market to identify active ingredients promoting cognitive functions and examine their properties related to anti-doping rules. Results from the market analysis revealed 34 substances/extracts of plant/mushroom origin and 120 synthetic substances with potential procognitive properties. Among the synthetic substances, 45 were labelled as 'unclear', including 19 presumed to 'meet WADA criteria'. In conclusion, the term 'brain doping' currently serves more as a marketing tool than as a concept describing a group of substances with scientifically proven cognitive effects. Substances marketed to consumers as 'brain doping' include substances prohibited in sports, as mentioned on the WADA Prohibited List, and those permitted for use by athletes or of unclear status. The open-ended nature of the list of prohibited substances poses challenges in definitively determining the status of many substances found in dietary supplements or medications, which may lead to unintentional violations of anti-doping rules.

The popularity of women's football has substantially increased over the last few decades. Despite this growing interest, few studies have compared the evolution of the physical performance of female football players across different age categories, and none have been conducted with players from the same club. Similarly, no studies have compared this progression between female and male players. We compared the evolution of speed-power qualities in female and male players from the same club throughout their specialization process, from the under-20 to the senior category. A total of 101 youth and senior female and male football players performed vertical jump, sprint speed, change-of-direction (COD) speed, and jump-squat power tests in this order, each conducted on separate occasions. Additionally, sprint momentum (SM) and COD-Deficit were also computed. Senior players demonstrated superior countermovement jump performance compared to under-20 players in both groups (ES = 0.86-0.93; P < 0.05). No significant differences were observed in squat jump and jump-squat power between under-20 and senior players (P > 0.05). Similarly, no differences were found in any speed-related tests between under-20 and senior players in either group (P > 0.05). SM and COD-Deficit were similar across age categories for both sexes; however, SM was higher in men (ES ≥ 2.05), while COD-Deficit was lower in female players (ES ≥ 2.08; P < .001). In conclusion, men outperformed women in all physical tests, with smaller differences in speed-related performance (Difference ≤ 14.2%). This gap was even narrower in more complex speed tasks, such as COD drills (Difference ≤ 4.7%), and may be attributed to the significant difference in SM; greater in male players) and its impact on the COD-Deficit.

Combining beetroot juice (BRJ) supplementation with blood flow restriction (BFR) training shows potential to meet the dual demand for enhanced muscle strength and improved fatigue resistance. This study involved 21 male college athletes who were randomized to a BFR group (n = 10) and a BFR-supplemented BRJ group (n = 11, nitrate 8 mmol/day) for 4 weeks of isokinetic BFR training. The strength (at 60°/s, 180°/s, and maximal voluntary isometric contraction) and fatigue resistance of the knee extensors and flexors were assessed pre- and post-intervention using an isokinetic dynamometer and a 30-second anaerobic power test, respectively. The four-week BFR and BFR+BRJ interventions significantly (P < 0.05) improved knee extensor/flexor peak torque and power (at 60°/s and 180°/s), while also delaying the decline in knee extensor torque during the 100-repetition maximal voluntary contraction test. The BFR+BRJ group showed a more significant advantage in the second half of the contraction (51-100 repetitions; P < 0.01). In addition, both interventions significantly reduced the rate of decline in peak torque, peak power, and average power at 60°/s and 180°/s after fatigue, with the reductions being more pronounced in the BFR+BRJ group (P < 0.01). In the anaerobic power test, the BFR+BRJ group maintained a higher power output for a longer duration (P < 0.05) compared to before the intervention, whereas the improvement in the BFR group was limited to the initial 3-10 seconds (P < 0.05). The results suggest that BFR combined with BRJ is an effective training method for improving knee extensor strength performance and fatigue resistance.

This study aims to analyze the differences in Physical Activity Enjoyment Scale (PACES) scores and exercise intensity across small-sided games (SSGs) and high-intensity interval training (HIIT) formats among soccer players from Tier 2 and Tier 3 competitive levels. Utilizing a cross-sectional design, 77 male players (20.64 ± 1.56 years) participated in four training sessions under controlled conditions. Enjoyment was assessed with PACES, while exercise intensity was monitored through heart rate and rating of perceived exertion (RPE). The training formats included 1 v 1 and 5 v 5 SSGs and long and short HIIT formats. Players were categorized as Amateur (Tier 2) or Competitor (Tier 3) based on training volume and performance level. The training formats included 1 v 1 and 5 v 5 SSGs and long and short HIIT formats. The present study revealed significant differences in PACES scores across the different training formats (p < 0.001), with the 5 v 5 format yielding the highest scores and long HIIT the lowest. A significant interaction between training format and competitive level was observed (p = 0.011). Tier 2 players reported higher PACES scores in the 5 v 5, 1 v 1, and Short HIIT formats compared to Tier 3 players. SSGs and HIIT formats significantly influence enjoyment, with smaller-sided formats (1 v 1) and short HIIT showing the highest enjoyment levels. Tier 2 players reported higher enjoyment and physical efforts than Tier 3 players, in 5 v 5, 1 v 1, and short HIIT formats. These findings show the importance of programming training sessions according to the competitive level of athletes to maximize enjoyment and manage effort in soccer training programs.

The present study aimed to assess the global chronic kidney disease due to diabetes mellitus type 2 (CKD-T2DM) attributable to low physical activity (PA) and high body-mass index (BMI). Data on CKD-T2DM deaths, disability-adjusted life years (DALYs), and risk factor exposure were obtained from the Global Burden of Disease Study 2021. The jointpoint model was used to detect the temporal patterns throughout the past 32 years, and the age-period-cohort analyses were preformed to clarify the trends in epidemiological shift. The global age-standardized rate (ASR) of DALYs for CKD-T2DM linked to low PA were 8.19 (95% UI, 3.21 to 13.60) per 100,000 people. No significant percent changes were observed since 1990. Globally, high BMI accounted for 50.14 (95% UI, 22.56 to 79.15) ASR of DALYs with a marked increase of 62.66 %(95 % UI, 44.24 to 78.73) from 1990. Both low PA and high BMI-attributable CKD-T2DM showed a surging trend in population aged less than 40 or greater than 75. There were consistent nonlinear trajectories between socio-demographic index (SDI) and CKD-T2DM attributable to low PA and high BMI, which reached a peak at SDI = 0.6 before decreasing with a higher SDI value. Globally, there are rising trends in CKD-T2DM burden, low PA exposure, and high BMI exposure until 2050. There are secular improvements in CKD-T2DM attributable to low PA, while it remains a severe challenge in that of high BMI. Considerable temporal and regional variation highlight the urgency of structural, context-specific strategies targeted on modifiable factors to tackle the CKD-T2DM burden.

This study aimed to assess the impact of a 5-week intervention that combined foam rolling (FR) and static stretching (SS) on ankle dorsiflexion range of motion (ROM). Furthermore, the study evaluated the influence of the intervention on leaping ability utilizing the counter-movement jump test (CMJ). Random assignment was used to allocate fifty-one amateur sports enthusiasts to either the foam rolling + static stretching (FR-SS) group (n = 22; age: 19.3 ± 6.87 years; height: 171 ± 7.91 cm; weight: 66.7 ± 9.52 kg) or the static stretching (SS) group (n = 29; age: 18.5 ± 4.60 years; height: 171 ± 11.5 cm; weight: 68.3 ± 16 kg). A baseline assessment (T0) and an assessment following the 5-week intervention (T1) were carried out. An inertial sensor was used to quantify the ankle joint ROM, and an optical detecting system was used to measure the CMJ performance. Significant differences were found between T0 and T1 in the FR-SS group. Significant group-by-time interaction effects (F = 14.44; p < 0.001, η²p = 0.128) and between-subject effects (F = 53.5; p < 0.001, η²p = 0.353) were found. Significant enhancements in CMJ performance (p < 0.01) were noted after the intervention in the FF-SS group. A similar trend was not observed in the SS group. Our findings suggest that a 5-week intervention combining FR with SS leads to greater improvements on ROM and angular velocity of the ankle joint, and on CMJ performance compared to SS alone. If further research confirms these results, FR and SS could be widely used in sports and rehabilitation.

The aim of this study was to examine the accelerations carried out by professional football players during an elite standard competition in relation to the initial running speed. An additional purpose was to determine the acceleration-speed (AS₀) profile of the players in relation to the position in the team formation.

Methods: A total of 8426 match observations from 363 players, categorized into six positional roles, who took part in the Spanish First Division (LaLiga) were examined with a semi-automatic multiple-camera video system during three consecutive seasons (from 2020-21 to 2022-23). The value of every acceleration performed during the games was related to its initial running speed, and the individual maximal and mean AS₀ profiles of all the players were calculated using linear regression models.

Results: A strong inverse relationship was detected between the acceleration values and the initial running speed for both the MaxAS₀ and the MeanAS₀ profiles (r = -0.990; p < 0.001 and r = 0.946; p < 0.001, respectively). This trend was consistent across all playing positions, with forwards exhibiting the greatest acceleration capacity and central defenders the smallest. There were differences (p < 0.05-0.001) in the slope of the AS₀ profile between playing positions.

Conclusions: This study shows that traditional fixed acceleration thresholds might overestimate high-intensity efforts that begin at low movement speeds and underestimate those that start at higher speeds. Thus, AS₀ profiles can provide a valuable tool to monitor physical match performance more objectively and help to discriminate the acceleration capacity between playing positions.