The Paradoxical Effect of Creatine Monohydrate on Muscle Damage Markers: A Systematic Review and Meta-Analysis

Background: Several studies have examined the effect of creatine monohydrate (CrM) on indirect muscle damage markers and muscle performance, although pooled data from several studies indicate that the benefits of CrM on recovery dynamics are limited. Objective: This systematic review and meta-analysis determined whether the ergogenic effects of CrM ameliorated markers of muscle damage and performance following muscle-damaging exercises. Methods: In total, 23 studies were included, consisting of 240 participants in the CrM group (age 23.9 ± 10.4 years, height 178 ± 5 cm, body mass 76.9 ± 7.6 kg, females 10.4%) and 229 participants in the placebo group (age 23.7 ± 8.5 years, height 177 ± 5 cm, body mass 77.0 ± 6.6 kg, females 10.0%). These studies were rated as fair to excellent following the PEDro scale. The outcome measures were compared between the CrM and placebo groups at 24–36 h and 48–90 h following muscle-damaging exercises, using standardised mean differences (SMDs) and associated p-values via forest plots. Furthermore, sub-group analyses were conducted by separating studies into those that examined the effects of CrM as an acute training response (i.e., after one muscle-damaging exercise bout) and those that examined the chronic training response (i.e., examining the acute response after the last training session following several weeks of training). Results: According to the meta-analysis, the CrM group exhibited significantly lower indirect muscle damage markers (i.e., creatine kinase, lactate dehydrogenase, and/or myoglobin) at 48–90 h post-exercise for the acute training response (SMD − 1.09; p = 0.03). However, indirect muscle damage markers were significantly greater in the CrM group at 24 h post-exercise (SMD 0.95; p = 0.04) for the chronic training response. Although not significant, a large difference in indirect muscle damage markers was also found at 48 h post-exercise (SMD 1.24) for the chronic training response. The CrM group also showed lower inflammation for the acute training response at 24–36 h post-exercise and 48–90 h post-exercise with a large effect size (SMD − 1.38 ≤ d ≤  − 1.79). Similarly, the oxidative stress markers were lower for the acute training response in the CrM group at 24–36 h post-exercise and 90 h post-exercise, with a large effect size (SMD − 1.37 and − 1.36, respectively). For delayed-onset muscle soreness (DOMS), the measures were lower for the CrM group at 24 h post-exercise with a moderate effect size (SMD − 0.66) as an acute training response. However, the inter-group differences for inflammation, oxidative stress, and DOMS were not statistically significant (p > 0.05). Conclusion: Overall, our meta-analysis demonstrated a paradoxical effect of CrM supplementation post-exercise, where CrM appears to minimise exercise-induced muscle damage as an acute training response, although this trend is reversed as a chronic training response. Thus, CrM may be effective in reducing the level of exercise-induced muscle damage following a single bout of strenuous exercises, although training-induced stress could be exacerbated following long-term supplementation of CrM. Although long-term usage of CrM is known to enhance training adaptations, whether the increased level of exercise-induced muscle damage as a chronic training response may provide potential mechanisms to enhance chronic training adaptations with CrM supplementation remains to be confirmed

Quantification of Pre-Season and In-Season Training Intensity across an Entire Competitive Season of Asian Professional Soccer Players

The aim of this study was to quantify the training load in two microcycles (Ms) from pre- and another two from in-season and to analyze playing position influences on the load experienced by professional soccer players. Nineteen Asian athletes, including four central defenders, four wide defenders, six central midfielders, three wide midfielders, and two strikers participated in this study. The micro-electromechanical system was used to collect training duration, total distance, and data from Zone 1 (0–3.9 km·h−1), Zone 2 (4–7.1 km·h−1), Zone 3 (7.2–14.3 km·h−1), Zone 4 (14.4–19.7 km·h−1), and Zone 5 (>19.8 km·h−1), heart rate maximum (HRmax), and average (HRavg). The load was reduced on the last day of the Ms, with the exception of Zone 5, in M1, where higher values were found on the last day. Significant differences were observed between central and wide defenders for distance covered in Zone 4 (effect-size: ES = −4.83) in M2 and M4 (ES = 4.96). Throughout all the Ms, a constant HRmax (165–188 bpm) and HRavg (119–145 bpm) were observed. There was a tendency to decrease the load on the last day of the Ms. In general, there were higher external training loads in Ms from the pre-season than in-season. Wide defenders and wide midfielders showed higher distances covered with high-intensity running.info:eu-repo/semantics/publishedVersio

Exploring the influence of task and environmental constraints on batting and bowling performance in cricket: A systematic review

Cricket is an unique international sport where environmental and task constraints have shown to have a significant impact on batting and bowling performance. The aim of this systematic review was to determine the effect of task and environmental constraints on cricket performance. A systematic literature search was conducted across Scopus, PubMed, Web of Science, CINAHL, and SportDiscus. Studies were deemed eligible if they reported the effects of pitch type, pitch length, equipment (e.g. cricket bat, batting pads, ball type, etc.) on cricket performance. A total of 20 studies met the inclusion criteria with Kmet score ranging between 75% and 92%. The results from this study demonstrate that environmental constraints such as pitch-type and task constraints such as equipment modification (e.g. type of cricket bat, batting pads, ball) and pitch length can influence cricketer's batting and bowling performance. Scaling cricket bats and reducing pitch length were acutely beneficial to cricket batting, while ball type, pitch length and soil properties were impactful on bowling performance. Importantly though, the impact of constraint manipulation seemed to be influenced by the skill level of the performer. The findings from this study may help to inform coaches and practitioners improve skill acquisition, through constraint manipulation, to develop highly adaptive cricket batting and bowling skill

The correlation of force-velocity-power relationship of a whole-body movement with 20 m and 60 m sprint performance

Sprinting ability is important for successful performance in sports. The aim of this study was to examine the correlation between force-velocity-power relationship of a whole-body movement and sprint performance. Twelve male participants performed maximal squat jumps with additional loads ranging from 0% to 100% body weight to obtain force-velocity profiles. The mean force and velocity were calculated during the push-off phase for each jump, which resulted in a force-velocity curve. The theoretical maximal force (F0), theoretical maximal velocity (V0) and theoretical maximum power (P0) were computed via extrapolation of the force and velocity data. In the second session, participants performed two 60 m sprints and the time to cover 20 m (t20), time to cover 60 m (t60), and maximum sprint velocity (Vmax) were calculated from the best 60 m trial. Correlation analyses revealed strong and significant correlations between V0 and t20 (r = −0.60), V0 and t60 (r = −0.60), P0 and t20 (r = −0.75) and P0 and t60 (r = −0.78). Multiple linear regression indicated that P0 explained 56%, 61% and 60% of the variability in t20, t60 and Vmax, respectively. Our results emphasise the importance of developing power production capabilities to improve sprint performance

Strength and conditioning practices for the optimisation of speed and accuracy in cricket fast bowlers: A systematic review and meta-analysis

The most important determinants of a cricket fast bowler’s performance are bowling speed and accuracy. Even though various strength and conditioning practices (resistance, plyometric and modified-implement training) have been employed to improve these parameters, there is still ambiguity as to the effectiveness of such training programmes. This systematic review and meta-analysis examined the influence of various training interventions on fast bowling speed and accuracy. Searches were conducted across PubMed, Web of science, SPORTDiscus, Scopus and CINAHL. Inclusion criteria were studies that: were original research or conference presentations; recruited fast bowlers as participants; involved a physical training intervention; written in English; and included bowling speed or accuracy as outcome measures. Ten articles met our inclusion criteria for qualitative and eight for quantitative analysis. The quality of the studies assessed using Downs and Black checklist ranged from low to moderate with a mean ± SD of 64.5 ± 8.14%. There was a moderate and significant effect of plyometric training intervention on bowling speed (SMD = 0.75; Z = 2.98; p = 0.003). Further, a small and non-significant effect of resistance training on bowling speed was observed in our study (SMD = 0.40; Z = 1.39; p = 0.164). A small but non-significant difference was found in the ball speed post modified ball weight training intervention (SMD = 0.30; Z = 1.14; p = 0.252). The findings from our study are useful for strength and conditioning coaches in helping to design and implement fast-bowling specific training programmes for improved bowling speed

Sex-based differences in concussion incidence and its underlying injury mechanism in team bat/stick sports: A systematic review and meta-analysis

This study aimed to synthesize and quantify the sex-based differences in concussion incidences rate and associated mechanism of injuries in team bat/stick sports. Following a systematic search across five electronic databases, 46 studies were included in the review; 24 were included in the incidence rate (IR) meta-analysis and 13 of the 24 studies met the eligibility criteria for the meta-analysis involving injury mechanism. DerSimonian and Laird random effects models were used for pooling the Rate Ratio (RR) data. Ice-hockey had the highest overall risk of concussion, followed by lacrosse and baseball/softball. Female players had higher concussion IRs compared to males (RR 0.74 [95% CI 0.58–0.95], p = .02) across all sports included in this study. Sex-based differences in concussion IRs for ice-hockey and lacrosse were not statistically significant. Male athletes were more statistically likely to sustain concussion because of player-contact in ice-hockey (RR 1.55 [95% CI 1.29–1.86], p < .001) and lacrosse (RR 3.20 [95% CI 1.54–6.64], p = .002). Conversely, female athletes showed a higher risk of concussion due to equipment contact in lacrosse (RR 0.29 [95% CI 0.20–0.43], p < .001). Injury mechanism varies between male and female athletes across these bat/stick sports. Female athletes have a higher risk of getting concussed due to the impact of players with equipment (ball/puck) and surface contact for lacrosse and ice-hockey. Findings from this study can help coaches, sports administrators, and health care providers with further data on the current information regarding concussion-related factors in these respective sports

Biomechanical and physical determinants of bowling speed in cricket: a novel approach to systematic review and meta-analysis of correlational data

This systematic review and meta-analysis examined the influence of biomechanical and physical characteristics on ball release speed in cricket using correlation data. Search was conducted across PubMed, Cinhal, Scopus, SportDiscus and Web of Science, with eighteen studies included. The ball release speed had a moderate correlation with overall biomechanical (r = 0.42, p < 0.001) parameters and a strong correlation with physical (r = 0.65, p < 0.001) characteristics. Furthermore, individual biomechanical and physical parameters were also correlated with ball release speed. The run-up speed had a strong correlation (r = 0.50, p < 0.001) and front knee angle at ball release had a moderate correlation (r = 0.40, p < 0.001). Poorer correlations were identified for centre of mass velocity at ball release (r = 0.16, p = 0.134), front knee angle at front foot contact (r = 0.26, p = 0.015) 25 and vertical ground reaction force (r = 0.13, p = 0.659). Strong and significant correlation was found for total arm length (r = 0.65, p < 0.001) and shoulder strength (r = 0.58, p < 0.001). This review highlights the biomechanical and physical parameters that are major determinants of faster ball release speed

The effect of leaf extract supplementation on exercise-induced muscle damage and muscular performance: a systematic review and meta-analysis

This systematic review and meta-analysis investigated the effects of leaf-plant extracts typically used for tea beverages on the level of exercise-induced muscle damage. The meta-analysis was conducted by comparing measures between the leaf-extract supplements (SUPP) and placebo (PLA) conditions at 24 h and 48 h following the muscle-damaging protocols from 19 studies with 416 participants. The results showed that the SUPP condition exhibited significantly lower indirect muscle damage markers than the PLA condition at 24- and 48-h post-exercise (p 0.05) between conditions. Muscle performance measures significantly increased for the SUPP condition than the PLA condition at 24-h post-exercise (p [removed] 0.05). These results demonstrate that leaf plant extracts reduces the level of various biomarkers indicative of exercise-induced stress, although its effect on anti-oxidant status remains equivocal. Nonetheless, leaf-plant extracts typically ingested as a tea beverage may be an effective recovery strategy following strenuous exercises

Relationship between Variations in the Accumulated Workload and the Change of Direction Ability in Elite Young Soccer Players

Background: The main aim of this study was to evaluate the relationships between training workload (WL) parameters with variations in the change of direction (COD) in under-16 soccer players. Methods: Twenty-seven under-16 elite soccer players were daily monitored for their WL across 15 weeks during the competitive soccer season. Additionally, players were assessed two times for anthropometric measures (weight, height, sitting height and leg length), COD performance (modified 505 test) and maturity offset measured using the peak height velocity (PHV). Results: A correlational analysis was performed to determine the relationship between the variation in COD performance and accumulated WL parameters. Moreover, a regression analysis was executed to explain the variations in the percentage of COD performance considering the accumulated WL parameters and PHV of the season (r = 0.93; p ≤ 0.01) and training monotony during the early-season (r = 0.53; p ≤ 0.05). There were associations between the acute workload during the start of the season and the COD during the end of the season (r = 0.47; p ≤ 0.05). The multiple linear regression analysis showed that 55% of the variation in COD performance between the early and end of season could be explained by the acute or chronic WL, training monotony or strain and the PHV. Conclusions: This information might be useful for practitioners and coaches aiming to improve the COD performance in youth soccer players during an entire competitive season

Relationship between Variations in the Accumulated Workload and the Change of Direction Ability in Elite Young Soccer Players

Background: The main aim of this study was to evaluate the relationships between training workload (WL) parameters with variations in the change of direction (COD) in under-16 soccer players. Methods: Twenty-seven under-16 elite soccer players were daily monitored for their WL across 15 weeks during the competitive soccer season. Additionally, players were assessed two times for anthropometric measures (weight, height, sitting height and leg length), COD performance (modified 505 test) and maturity offset measured using the peak height velocity (PHV). Results: A correlational analysis was performed to determine the relationship between the variation in COD performance and accumulated WL parameters. Moreover, a regression analysis was executed to explain the variations in the percentage of COD performance considering the accumulated WL parameters and PHV of the season (r = 0.93; p &le; 0.01) and training monotony during the early-season (r = 0.53; p &le; 0.05). There were associations between the acute workload during the start of the season and the COD during the end of the season (r = 0.47; p &le; 0.05). The multiple linear regression analysis showed that 55% of the variation in COD performance between the early and end of season could be explained by the acute or chronic WL, training monotony or strain and the PHV. Conclusions: This information might be useful for practitioners and coaches aiming to improve the COD performance in youth soccer players during an entire competitive season