Peak running speed can be used to monitor neuromuscular fatigue from a standardized running test in team sport athletes.

This study compared the sensitivity of peak running speed (PRS) measured during a submaximal run test (SRT) with a countermovement jump (CMJ) test to provide an alternate method of measuring neuromuscular fatigue (NMF). The study involved 20 semi-professional academy soccer players who performed a SRT and CMJ test, 24-hours pre-match, 24-, 48-, 72- and 96-hours post-match. Moderate decreases (effect-size (ES) ± 90% confidence intervals) were observed 24-hours post-match for CMJH; ES -0.70 ± 0.19, CMJPV; ES -0.92 ± 0.27 and PRS; ES -0.58 ± 0.11 with small decreases in CMJH; ES -0.36 ± 0.13 and PRS; ES -0.27 ± 0.23 still evident 48-hours post-match before returning to baseline 72-hours post-match. The results confirm PRS as an inexpensive alternate method of measuring NMF which, allows instantaneous real-time feedback on NMF. This can allow changes to be made immediately on-field within the post-match recovery phase without the need for further analysis or equipment.

Jump rope training effects on health- and sport-related physical fitness in young participants: A systematic review with meta-analysis.

The aim of this systematic review with meta-analysis was to assess the available body of published peer-reviewed articles related on the effects of jump rope training (JRT) compared with active/passive controls on health- and sport-related physical fitness outcomes. Searches were conducted in three databases, including studies that satisfied the following criteria: i) healthy participants; ii) a JRT programprogramme; iii) active or traditional control group; iv) at least one measure related to health- and sport-related physical fitness; v) multi-arm trials. The random-effects model was used for the meta-analyses. Twenty-one moderate-high quality (i.e., PEDro scale) studies were meta-analysed, involving 1,021 participants (male, 50.4%). Eighteen studies included participants with a mean age <18 years old. The duration of the JRT interventions ranged from 6 to 40 weeks. Meta-analyses revealed improvements (i.e., p = 0.048 to <0.001; ES = 0.23-1.19; I2 = 0.0-76.9%) in resting heart rate, body mass index, fat mass, cardiorespiratory endurance, lower- and upper-body maximal strength, jumping, range of motion, and sprinting. No significant JRT effects were noted for systolic-diastolic blood pressure, waist-hip circumference, bone or lean mass, or muscle endurance. In conclusion, JRT, when compared to active and passive controls, provides a range of small-moderate benefits that span health- and sport-related physical fitness outcomes.

Muscle injury characteristics and incidence rates in men's amateur soccer: A one season prospective study.

The objectives of the study were to examine the incident rate (IR), characteristics, and mechanisms of muscle injuries of 121 men amateur soccer players that voluntarily participated in this project. Sixty-five muscle injuries with an overall IR of 3.62/1000 h, 95% CI 2.7-4.5, were reported. The most frequently injured muscle groups were the hamstrings (IR 1.78/1000 h, 95% CI 1.1-2.3), followed by the adductors (IR 1.5/1000 h, 95% CI 0.93-2.06). Most muscle injuries were characterized as mild (IR 2.3/1000 h, 95% CI 1.53-2.92) or minimal (IR 1.28/1000 h, 95% CI 1.16-2.39. Higher incidence of injury sustained during matches (IR 14.09 injuries/1000 h, 95% CI 9.49-18.7), than in training (IR 1.88 injuries/1000 h, 95% CI 1.19-2.56). The most frequent injury mechanisms were high-speed running (84.4%) and change of direction (44.4%), for hamstring and adductors-related groin injuries, respectively. Players aged over 24 years had a 7-fold increased risk to sustain a hamstring injury but a lower risk to sustain an adductor-related groin injury. Injury prevention and rehabilitation management strategies may reduce muscle injury rates in amateur soccer.

Foam rolling and tissue flossing of the triceps surae muscle: an acute effect on Achilles tendon stiffness, jump height and sprint performance - a randomized controlled trial.

This study aimed to investigate an acute effect of foam rolling and tissue flossing of the Triceps Surae muscle on Achilles tendon stiffness, jump height and sprint performance at different time points. The participants were academic athletes (n = 32) aged between 22 and 24 years; randomly allocated into two groups: foam rolling (ROLL) and tissue flossing (FLOSS). The participants were tested at baseline and 5-min, 15-min, 30-min, 45-min, and 60-min after ROLL and FLOSS for Achilles tendon stiffness (ATstiffeness) at three reference locations: (1) tendon's origin, (2) ankle joint height and (3) intermuscular septum of the gastronomies muscle; countermovement jump (CMJ); and sprint performance at 15-m (SPRINT15 m). The analysis of stiffness revealed a significant decrease in ATstiffness from baseline to Post-60 (p ≤ 0.001) for three locations in the FLOSS group (p ≤ 0.001). In FLOSS, a significant increase was observed from Post-15 to Post-60 (all p≤0.001) in CMJ. We found also a significant decrease in SPRINT15 m in FLOSS in all-time points (p ≤ 0.001), however, SPRINT15 m decreased in Post-5 min, Post-15 min, and Post-30 min (p ≤ 0.001 for all) in ROLL. The current study suggested that both groups enhanced performance up to 60 min after the intervention, caused by mitigating excessive stiffness.

Effects of high-intensity interval training in men soccer player's physical fitness: A systematic review with meta-analysis of randomized-controlled and non-controlled trials.

This systematic review with meta-analysis (SRMA) was conducted to assess the effects of high-intensity interval training (HIIT) programmes on men soccer players' aerobic fitness (maximal oxygen uptake and aerobic performance), repeated sprint ability (RSA), vertical jump height (VJH), and linear sprinting time (ST). An electronic search yielded 1,714 articles, 33 of which were included in the present study. Meta-analyses revealed significant benefits of HIIT compared to controls in maximal oxygen uptake (p = 0.018), AP (p = 0.041), and RSA (p = 0.049). No significant effects were found in terms of ST (p = 0.080). The meta-analyses of non-controlled studies revealed significant improvements after HIIT in maximal oxygen uptake (p = 0.001), AP (p = 0.007), RSA (p = 0.001), and ST (p < 0.001). However, no significant improvements in VHJ were found (p = 0.063). Furthermore, no significant differences were found in sub-group analysis (comparisons between HIIT types). In conclusion, HIIT is effective for improving maximal oxygen uptake, AP, and RSA regardless of the HIIT type. For VHJ and ST outcomes, it seems reasonable to complement the HIIT since it might not be enough to achieve significant changes.

Session-to-session variations of internal load during different small-sided games: a study in professional soccer players.

The aim of this study was to analyse variations of internal load across small-sided games (SSG) in professional soccer. Twenty players (mean ± SD; age 28.1 ± 4.6 yo, height 176.7 ± 4.9 cm, weight 72.0 ± 7.8 kg) performed 3v3, 4v4, and 6v6 formats with/without goalkeeper and touch limitations. Each condition was repeated over three sessions and heart rate (HR) measures including average HR (HRavg), Edwards' training impulse (Edwards' TRIMP) and time in red zone (>80% of maximal HR) were recorded. All measures had trivial-to-moderate typical error (TE) and trivial differences were observed within intervals. The HRavg showed less coefficient of variations (0.9% to 1.7%) compared to Edwards'TRIMP.min-1 and red zone.min-1 (2% to 9.7%). A reduction trend in TE was observed when touching limitations or using goalkeepers. Practitioners can use different SSG formats but if the aim is to have less noise at higher intensities, more controlled drills are recommended.

Longitudinal differences in the injury profile of professional male handball players according to competitive-level.

The aim was to analyse the differences in professional handball players` injury profile according to the team`s competitive-level (i.e., First division vs. Second division). Fifty-three professional male handball players participated in this study during four consecutive seasons in the same team (2015-16 and 2016-17 for the First division league and 2017-18 and 2018-19 for the Second division league). No significant differences in overall incidence were observed between groups (3.69 vs 4.19 injuries/1000 h, RR = 0.88, 95% CI 0.64-1.22, P = 0.44), although significantly greater injury incidence during training sessions was observed in the Second division group (3.06 vs 1.61 injuries/1000 h, RR = 0.52, 95% CI 0.34-0.81, P = 0.01), while greater injury incidence during matches was reported in the First division group (84.03 vs 49.88 injuries/1000 h, RR = 1.68, 95% CI 1.00-2.83, P = 0.05). The second division group presented the greatest injury burden attending to overall, training and match exposure, as well as in most locations and injury types. Given the between groups differences found in the injury profile of handball player, it is suggested to implement specific preventive strategies attending to the characteristics of each level-group.

Recreational football is medicine against non-communicable diseases: A systematic review.

The purpose of this research was to conduct a systematic review of published articles related to the effect of recreational football on non-communicable diseases. A systematic review of Web of Science, SPORTDiscus, MEDLINE, and PubMed databases was performed according to PRISMA guidelines. Only empirical studies were included. There were no restrictions on the types of study design eligible for inclusion. The primary outcome measures result from the potential effects of recreational football on non-communicable diseases (eg, blood pressure, bone density, LDL cholesterol, and fat mass). A total of 44 articles met the inclusion criteria and were included. Recreational football is shown to: (a) decrease blood pressure and resting heart rate, improve cardiac structure and functioning, as well as increase maximal oxygen uptake in both sexes; (b) reduce cholesterol and triglycerides levels, increase insulin sensitivity, and have a positive impact on glycemic control; (c) improve bone mineralization, increase both bone mineral density and content, as well as acting as a stimulus for osteogenesis; and (d) be clearly beneficial for bone health, while slightly beneficial for body composition, muscle strength, and maximal oxygen uptake in adults with prostate cancer. The present systematic review demonstrated the benefits of recreational football practice on non-communicable diseases related to cardiovascular and bone health, body composition, type 2 diabetes, and prostate cancer. The effectiveness of recreational football on the aforementioned diseases may be related to age and gender; however, further research is required.

Effects of plyometric jump training in female soccer player's vertical jump height: A systematic review with meta-analysis.

To assess the effects of plyometric jump training (PJT) in female soccer player's vertical jump height, a review was conducted using the data sources PubMed, MEDLINE, Web Of Science and SCOPUS. Only peer-review articles were included. To qualify for inclusion in the meta-analysis, studies must have included (i) a PJT programme of at least 2 weeks, (ii) cohorts of healthy female soccer players with no restriction for age, (iii) a control group, (iv) a measure of countermovement jump (CMJ). The inverse variance random-effects model for meta-analyses was used. From 7,136 records initially identified through database searching, 8 were eligible for meta-analysis, comprising 9 training groups (n = 99) and 9 control groups (n = 94). The magnitude of the main effect was moderate (ES = 1.01 [95%CI = 0.36-1.66], Z = 3.04, p = 0.002). Sub-group analyses were performed (i.e., PJT frequency, duration and total number of sessions), revealing no significant subgroup differences (p = 0.34-0.96). Among the studies included in this review, none reported injury or other adverse effects. In conclusion, PJT is effective in female soccer players for the improvement of vertical jump height. In future, research must identify specific dose-response relationships following PJT, particularly in the long term.

The influence of offside rule and pitch sizes on the youth soccer players' small-sided games external loads.

The aim was to analyse the influence of the offside rule and pitch sizes on the external loads encountered by young soccer players during small-sided games (SSGs). Twenty-four U12 soccer players belonged to the same Spanish Performance Soccer Academy participated in the study. Each player participated in six different SSGs attending to the offside rule (i.e., offside not applicable [NOS] and with offside [WOS]) and the pitch sizes (i.e., individual interaction space [IIS] of 25, 50 and 75 m2 per player). The obtained data included measures of external loads by global positioning systems. Players covered higher total distance and greater distances at jogging (8-12.9 km·h-1), cruising (13.0-16.0 km·h-1) and sprinting (>16.0 km·h-1) in NOS75 and WOS75 SSGs (p < 0.01; d = 0.65-6.60). Besides, in the NOS75 SSG, the total distance and the distance at cruising were higher in respect to WOS75 (p < 0.01; d = 0.63-0.82). In addition, players performed lower sprints (p < 0.01; d = 1.17-1.71) and achieved lower Vmax (p > 0.05; d = 1.10-1.88) during NOS25 and WOS25 SSGs. These findings could provide relevant information for coaches in order to apply different pitch sizes and the inclusion/absence of the offside rule throughout the microcycle.

The influence of youth soccer players' sprint performance on the different sided games' external load using GPS devices.

The aims of this study are 1) to compare sided games' (SGs) external responses encountered by players according to pitch size and to 2) examine the relationships between sprint performance and SGs' external physical responses. Twenty soccer players under 15 years of age (U-15) participated in this study. Each player performed a sprinting test (10 m and 30 m sprints) and played a SG on two different pitch sizes (small at 100 [SSG] and large at 200 [LSG] m2 per player). Higher external responses (p < 0.01, ES = -6.41-1.22) were found in LSG in comparison to SSG, except to distance accelerating and decelerating (p > 0.05, ES = -0.26-0.27). Players who were faster over 10 and 30 m covered higher distances cruising and sprinting (r = -0.47/-0.66; ± 0.23/± 0.30, respectively, p < 0.05), performed a greater number of sprints, achieved higher maximum velocity (Velmax) during LSG and covered a greater distance at high-intensity accelerating (r = -0.50/-0.70; ±0.21/±0.29, respectively, p < 0.05) during both SG. LSG demanded a higher external load in comparison with SSG. In addition, the improved sprint capacity could allow players to perform greater running activities and short-term actions at high-intensities during SG.

Anthropometry and fitness profile, and their relationships with technical performance and perceived effort during small-sided basketball games.

The purpose of this study was to analyze the relationships between anthropometric (height and weight), fitness status (aerobic capacity, Yo-Yo Intermittent Recovery Test - level 1, YYIRT-L1; countermovement jump performance, CMJ) and perceived exertion (RPE) of twenty youth (under-14 and under-16) male basketball players and their technical actions (attacking balls-AB, shots-S, received balls-RB, rebounds-R, conquered balls-CB, lost balls-LB) during five small-sided games (SSGs) formats (from 1v1 to 5v5). Pearson's product-moment correlation coefficients tested the relationships between the anthropometric and fitness variables and the technical actions and perceived exertion during SSGs. The results of this study revealed that both anthropometry and fitness variables are associated with technical performance during SSGs. However, correlations are not clear with the levels of perceived exertion reported by players. Coaches should be aware of such relationships to better design their SSGs format and implement basketball drills based on the specific players' characteristics.

Concurrent-Validity and Reliability of Photocells in Sport: A Systematic Review.

Specific physical qualities such as sprint running, change-of-direction or jump height are determinants of sports performance. Photocell systems are practical and easy to use systems to assess the time from point A to point B. In addition, these photoelectric systems are also used to obtain the time of vertically displaced movements. Knowing the accuracy and precision of photocell timing can be a determinant of ensuring a higher quality interpretation of results and of selecting the most appropriate devices for specific objectives. This systematic review aimed to identify and summarize studies that have examined the validity and reliability of photocells in sport sciences. A systematic review of PubMed, SPORTDiscus, and Web of Science databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. From the 164 studies initially identified, 16 were fully reviewed, and their outcome measures were extracted and analyzed. Photocells appear to have a strong agreement with force plates (gold standard), but are not interchangeable to measure the vertical jump. For monitoring horizontal displacement, double beam systems, compared to single beam systems, are more valid and reliable when it comes to avoiding false triggers caused by swinging arms or legs.

Influence of Pitch Size on Short-Term High Intensity Actions and Body Impacts in Soccer Sided Games.

The aim of this study was to compare external training loads between small-sided games (SSGs) and largesided games (LSGs) in soccer players. Twenty outfield soccer players (14.8 ± 0.6 years old) who competed in the Spanish U16 Provincial Division and belonged to the same team participated in the study. The soccer sided games were played at different individual interaction space (IIS) per player (i.e., SSG = 100 m2 and LSG = 200 m2) and were disputed in the same format (five-a-side plus goalkeepers) on two different pitch sizes (i.e., 38 x 26 vs. 53 x 37 m) defending an official soccer-goal. The sided games' duration was 4 bouts of 6 min with 2 min rest intervals between bouts. The results of this study showed no meaningful differences in the total distance and intensity of accelerations and decelerations between SSGs and LSGs except for the lower distance covered at medium intensity (2.5 - 4 m·s-2) observed during LSGs (-10.2%; ES (effect size): -0.51). Players registered greater sprints, maximum velocity (Velmax) and body impacts at different intensities (i.e., I5-6g, I6-6.5g, I6.5-7g, I7-8g, I8-10g,) in LSGs in comparison to SSGs. These findings suggest that an increase in the pitch size (i.e., IIS per player) can induce higher external loads for soccer players.