Male Amateur Soccer Players Research Articles

The effect of carbohydrate mouth rinse on intermittent sprint performance in soccer players

Aim: Carbohydrate (CHO) mouth rinsing in the oral cavity has been shown to increase especially endurance exercise performance. Mechanisms responsible for this ergogenic effect may be related to receptors in oral cavity that detect CHO, in turn, increase neural drive to the motor unite. The aim of this study was to examine the effects of CHO mouth rinsing on intermittent sprint performance in soccer players. Material and Method: With randomised, double-blind, crossover, counterbalanced research design, fifteen amateur male soccer players (Mean±SD age:20.00±2.44 years, height:177.66±4.80 cm, body mass:75.02±6.42 kg) completed 3 sessions consisting of 12x4 seconds intermittent sprint tests with administering 10-second mouth rinse protocols before each sprint; a-) %6.4 carbohydrate solution (CHO) b-) water as a placebo (PLA) and 3-) no rinse as a control (CON). At rest, immediately after test and in active and passive recevory periods, blood glucose (BG), blood lactate (BL), heart rate (HR) and rating of perceived exertion (RPE) were assessed. Results: Compared with the CON condition, CHO and PLA increased significantly peak and mean power output (P 0.05) but HR were significantly different in CON than CHO and PLA. Morover, RPE was significantly different in CON than PLA but not than CHO. Conclusion: CHO mouth rinsing does not improve peak and mean power when compared to PLA, but as a nocebo effect, CHO and PLA improve peak and mean power output with regard to CON.

Adding a post-training FIFA 11+ exercise program to the pre-training FIFA11+ injury prevention program reduces injury rates among male amateur soccer players: A cluster-randomised trial

Background: The FIFA 11+ program was designed to be a pre-training ‘warm-up’ before soccer training sessions, to ensure proper technique and improved neuromuscular coordination are achieved. However, it could be hypothesized that training in a fatigued state (post- training) might help players learn to control their movements while in this fatigued state, thereby providing a mechanism for reducing injury. Effects of the FIFA 11+ protocol in both pre and post- training have not been investigated and may be important. Participating in the FIFA 11+ program pre- and post-training during soccer training may further challenge and expose the athlete to physiological conditions known as ‘game-like’ conditions.

Effects of Sprint Training With and Without Weighted Vest on Speed and Repeated Sprint Ability in Male Soccer Players.

The purpose of this study was to assess the effect resisted sprint training using weighted vests (WVs) compared with unresisted sprint (US) training on physical fitness (countermovement jump, 10-m sprint, 30-m sprint, and repeated sprint ability [RSA]) in amateur male soccer players. Nineteen soccer players (age: 23.7 ± 4.5 years; height: 178.3 ± 5.8 cm; body mass: 72.9 ± 5.2 kg) were randomly assigned to a WV (n = 10) or a US (n = 9) group. The intervention program had to be performed 2 times a week over 6 weeks. The only difference between the 2 interventions was that the WV group performed all the sprints with an additional weight of 18.9% ± 2.1% of body mass. Within-group analysis showed significant improvements (p < 0.001) in 10-m and 30-m sprint performances from pretest to posttest in WV (+9.42% and +6.04%) and US (+10.87% and +5.10%). Players in both WV and US also showed significant enhancements in RSA average time (AT), fastest time, and total time from pretest to posttest. Percentage changes in 30-m sprint performance, for both groups combined, had a very large correlation with percentage changes in AT of RSA. In the between-groups analysis, there were no differences between the sprint training groups (WV vs. US) in any variable. In conclusion, the findings of this study indicate that both sprint training methods used seem to be effective to improve soccer-related performance measures, and could be beneficial to players and coaches in field settings.

Adding a post-training FIFA 11+ exercise program to the pre-training FIFA 11+ injury prevention program reduces injury rates among male amateur soccer players: a cluster-randomised trial.

Does adding a post-training Fédération Internationale de Football Association (FIFA) 11+ exercise program to the pre-training FIFA 11+ injury prevention program reduce injury rates among male amateur soccer players? Cluster-randomised, controlled trial with concealed allocation. Twenty-one teams of male amateur soccer players aged 14 to 35 years were randomly assigned to the experimental group (n=10 teams, 160 players) or the control group (n=11 teams, 184 players). Both groups performed pre-training FIFA 11+ exercises for 20minutes. The experimental group also performed post-training FIFA 11+ exercises for 10minutes. The primary outcomes measures were incidence of overall injury, incidence of initial and recurrent injury, and injury severity. The secondary outcome measure was compliance to the experimental intervention (pre and post FIFA 11+ program) and the control intervention (pre FIFA 11+ program). During one season, 26 injuries (team mean=0.081 injuries/1000 exposure hours, SD=0.064) were reported in the experimental group, and 82 injuries were reported in the control group (team mean=0.324 injuries/1000hours, SD=0.084). Generalised Estimating Equations were applied with an intention-to-treat analysis. The pre and post FIFA 11+ program reduced the total number of injuries (χ2 (1)=11.549, p=0.001) and the incidence of initial injury (χ2 (2)=8.987, p=0.003) significantly more than the pre FIFA 11+ program alone. However, the odds of suffering a recurrent injury were not different between the two groups (χ2 (1)=2.350, p=0.125). Moreover, the severity level of injuries was not dependent upon whether or not the pre and post FIFA 11+ program was implemented (χ2 (1)=0.016, p=0.898). Implementation of the FIFA 11+ program pre-training and post-training reduced overall injury rates in male amateur soccer players more than the pre FIFA 11+ program alone. ACTRN12615001206516. [Al Attar WSA, Soomro N, Pappas E, Sinclair PJ, Sanders RH (2017) Adding a post-training FIFA 11+ exercise program to the pre-training FIFA 11+ injury prevention program reduces injury rates among male amateur soccer players: a cluster-randomised trial. Journal of Physiotherapy 63: 235-242].

Accelerometer load: a new way to measure fatigue during repeated sprint training?

ABSTRACTPurpose:Prescribing the appropriate dose of repeated sprint training to a large number of players in a team sports environment presents a challenge to practitioners. Players experience fatigue and performance decrements at different rates, and so a means of monitoring this would be of interest to coaches. This study aimed to identify if accelerometer load could be used to detect the performance decrement during repeated sprints.Materials and Methods:Nine male semi-professional and amateur soccer players performed 25 m sprints (2 × 12.5 m with 180° change of direction) interspersed with 20 s passive recovery until a 5% performance decrement in sprint time was reached. Trunk segmental accelerations were measured at the thoracic spine using a triaxial accelerometer worn in a tight-fitting vest.Results:Sprint time increased by 8.5% (range 5–13%) from the first to the last sprint. Accelerometer load demonstrated a mean decrease of 15% (range 11–23%) from the first to the last sprint. Least squares linear regression revealed accelerometer decrement to be two to threefold greater than the sprint performance decrement. Additionally, strong within-participant associations between accelerometer load and sprint decrement with very large to nearly perfect correlations were observed (Pearson’s r = 0.84–0.99, P < 0.03).Conclusion:Practitioners may be able to utilize this concept to monitor the fatigue induced by repeated sprinting or high-intensity efforts in team sports training in order to prescribe sprint training relative to individual fatigue profiles.​

INJURIES IN 17–19 YEAR-OLD MALE AMATEUR SOCCER PLAYERS

BackgroundThere is only a small body of literature regarding injuries in male youth amateur soccer players. Yet such information is fundamental for effective prevention.ObjectiveAnalysis of injury patterns among 17–19 year...

Hamstring-and-Lower-Back Flexibility in Male Amateur Soccer Players

This study investigated the hamstring-and-lower-back flexibility (HLBF) of male adult amateur soccer players, using the sit-and-reach test (SRT), with a view to obtaining population-based reference values and to determining whether SRT scores are associated with player characteristics. Cross-sectional cohort study. Teams from high-level Dutch amateur soccer competitions were recruited for participation. Dutch male high-level amateur field soccer players (n = 449) of age 18 to 40 years. Players with a hamstring injury at the moment of SRT-measurement or any other injury that prevented them from following the SRT protocol were excluded. Sit-and-reach test scores were measured and then population-based reference values were calculated as follows: >2SD below mean (defining "very low" HLBF), 1SD-2SD below mean ("low" HLBF), 1SD below mean to 1SD above mean ("normal" HLBF), 1SD-2SD above mean ("high" HLBF), and >2SD above mean ("very high" HLBF). Whether SRT scores were correlated with player characteristics was determined using a Pearson correlation coefficient or Spearman rho. Sit-and-reach test scores ranged from 0 to 43.5 cm (mean 22.0 cm, SD 9.2). The cutoff points for population-based reference values were <3.5 cm for "very low", 3.5 to 13.0 cm for "low", 13.0 to 31.0 cm for "normal", 31.0 to 40.5 cm for "high", and >40.5 cm for "very high". Sit-and-reach test scores were significantly associated with players' height (ρ = -0.132, P = 0.005), body mass index (r = 0.114, P = 0.016), and history of anterior cruciate ligament surgery (P < 0.001). This study is the first to describe the HLBF of amateur soccer players. The SRT reference values with cutoff points may facilitate evidence-based decision making regarding HLBF, and the SRT might be a useful tool to assess injury risk, performance, or for diagnostic purposes.

Emergence of Exploratory, Technical and Tactical Behavior in Small-Sided Soccer Games when Manipulating the Number of Teammates and Opponents.

The effects that different constraints have on the exploratory behavior, measured by the variety and quantity of different responses within a game situation, is of the utmost importance for successful performance in team sports. The aim of this study was to determine how the number of teammates and opponents affects the exploratory behavior of both professional and amateur players in small-sided soccer games. Twenty-two professional (age 25.6 ± 4.9 years) and 22 amateur (age 23.1 ± 0.7 years) male soccer players played three small-sided game formats (4 vs. 3, 4 vs. 5, and 4 vs. 7). These trials were video-recorded and a systematic observation instrument was used to notate the actions, which were subsequently analyzed by means of a principal component analysis and the dynamic overlap order parameter (measure to identify the rate and breadth of exploratory behavior on different time scales). Results revealed that a higher the number of opponents required for more frequent ball controls. Moreover, with a higher number of teammates, there were more defensive actions focused on protecting the goal, with more players balancing. In relation to attack, an increase in the number of opponents produced a decrease in passing, driving and controlling actions, while an increase in the number of teammates led to more time being spent in attacking situations. A numerical advantage led to less exploratory behavior, an effect that was especially clear when playing within a team of seven players against four opponents. All teams showed strong effects of the number of teammates on the exploratory behavior when comparing 5 vs 7 or 3 vs 7 teammates. These results seem to be independent of the players’ level.

Very-Heavy Sled Training for Improving Horizontal-Force Output in Soccer Players.

Sprint running acceleration is a key feature of physical performance in team sports, and recent literature shows that the ability to generate large magnitudes of horizontal ground-reaction force and mechanical effectiveness of force application are paramount. The authors tested the hypothesis that very-heavy loaded sled sprint training would induce an improvement in horizontal-force production, via an increased effectiveness of application. Training-induced changes in sprint performance and mechanical outputs were computed using a field method based on velocity-time data, before and after an 8-wk protocol (16 sessions of 10- × 20-m sprints). Sixteen male amateur soccer players were assigned to either a very-heavy sled (80% body mass sled load) or a control group (unresisted sprints). The main outcome of this pilot study is that very-heavy sled-resisted sprint training, using much greater loads than traditionally recommended, clearly increased maximal horizontal-force production compared with standard unloaded sprint training (effect size of 0.80 vs 0.20 for controls, unclear between-groups difference) and mechanical effectiveness (ie, more horizontally applied force; effect size of 0.95 vs -0.11, moderate between-groups difference). In addition, 5-m and 20-m sprint performance improvements were moderate and small for the very-heavy sled group and small and trivial for the control group, respectively. Practical Applications: This brief report highlights the usefulness of very-heavy sled (80% body mass) training, which may suggest value for practical improvement of mechanical effectiveness and maximal horizontal-force capabilities in soccer players and other team-sport athletes. This study may encourage further research to confirm the usefulness of very-heavy sled in this context.

The Importance of Postural Control in Relation to Technical Abilities in Small-Sided Soccer Games.

Making assessments regarding postural control and balance is very important for injury prevention in soccer. However, there has been no study that has associated postural control variables with branch-specific technical properties in a game. The aim of the present study was to determine the relationships between variables designating postural control levels and technical performance variables in different (1:1, 2:2 and 3:3) small-sided games (SSGs). Sixteen trained male amateur soccer players volunteered to take part in the study (age 17.2 ± 1.02 years, body height 176.25 ± 0.07 m, body mass 67.67 ± 13.27 kg). Following familiarization sessions, postural control was evaluated using one-leg and both-leg quiet-stance positions by measuring postural sway with a Tekscan HR Mat™ in anterior–posterior and medial–lateral directions. Later, 1:1, 2:2 and 3:3 SSGs were performed at two-day intervals and the technical variables specified for each game were analyzed. A Spearman’s rank-order correlation analysis demonstrated the relationship between postural control and soccer-specific technical variables in 1:1 (r-values ranging from 0.582 to 0.776), 2:2 (rvalues ranging from 0.511 to 0.740) and 3:3 (r-values ranging from 0.502 to 0.834) SSGs. In addition, a Wilcoxon signed rank test revealed differences between SSGs in terms of several variables. The results of the study showed that higher postural control levels are among the important variables that affect success in the performance of technical skills under rival pressure and suddenly changing conditions. Therefore, it is recommended that in addition to its use for injury prevention purposes, balance training should be conducted to improve branch-specific technical skills and to increase the levels of their successful performance in a game.

No Relationship Between Hamstring Flexibility and Hamstring Injuries in Male Amateur Soccer Players: A Prospective Study

Background: In soccer, although hamstring flexibility is thought to play a major role in preventing hamstring injuries, the relationship between hamstring flexibility and hamstring injuries remains unclear. Purpose: To investigate the relationship between hamstring flexibility and hamstring injuries in male amateur soccer players. Study Design: Case-control study; Level of evidence, 3. Methods: This study included 450 male first-class amateur soccer players (mean age, 24.5 years). Hamstring flexibility was measured by performing the sit-and-reach test (SRT). The relationship between hamstring flexibility and the occurrence of hamstring injuries in the following year, while adjusting for the possible confounding effects of age and previous hamstring injuries, was determined with a multivariate logistic regression analysis. Results: Of the 450 soccer players, 21.8% reported a hamstring injury in the previous year. The mean (±SD) baseline score for the SRT was 21.2 ± 9.2 cm. During the 1-year follow-up period, 23 participants (5.1%) suffered a hamstring injury. In the multivariate analysis, while adjusting for age and previous injuries, no significant relationship was found between hamstring flexibility and hamstring injuries (P = .493). Conclusion: In this group of soccer players, hamstring flexibility (measured with the SRT) was not related to hamstring injuries. Age and previous hamstring injuries as possible confounders did not appear to influence this relationship. Other etiological factors need to be examined to further elucidate the mechanism of hamstring injuries.

Age-related Physical Performance Differences in Male Soccer Players

The aim of this study is to identify the differences of physical performance characteristics between the amateur male adolescent soccer players in different age groups. One hundred and twenty-eight...

Risk Factors for Noncontact Ankle Injuries in Amateur Male Soccer Players: A Prospective Cohort Study.

To determine whether nonmodifiable and modifiable risk factors [ankle dorsiflexion range of motion (ROM), lower limb power output, and balance], as identified in preseason screening, predict the risk of sustaining a noncontact ankle injury in amateur male soccer players during the training and competitive season. Prospective cohort study. Amateur soccer competition (club and area representative teams). Amateur soccer players (n = 210) aged ≥15 years. Height, weight, ankle dorsiflexion ROM, power (vertical jump) and balance (time of double-leg balanced stance on an electronic wobble board, maximum 20 seconds) measured in preseason screening. Incidence of noncontact ankle injury and exposure to both training and games, monitored during the competitive season following baseline measurement. Noncontact ankle injury was defined as any ankle injury not caused by a collision (with another player or object) resulting in a participant missing at least 1 game or training session. Fourteen of the 210 participants (6.7%) sustained a noncontact ankle injury yielding an injury rate of 0.484 injuries per 1000 player hours. Lower limb power output scores <30 W/kg [odds ratio (OR), 9.20, 95% confidence interval (CI), 1.13-75.09, P = 0.038] and poorer balance scores (OR, 0.43, 95% CI, 0.21-0.89, P = 0.024) were associated with higher odds of injury. Poorer lower limb power output and balance are risk factors for noncontact ankle injury among amateur soccer players. These deficits can potentially be identified by screening, providing opportunities to investigate prevention strategies.

Susceptibility to Hamstring Injuries in Soccer

Background: Running-related hamstring strain injuries remain a delicate issue in several sports such as soccer. Their unremittingly high incidence and recurrence rates indicate that the underlying risk has not yet been fully identified. Among other factors, the importance of neuromuscular coordination and the quality of interplay between the different hamstring muscle bellies is thought to be a key determinant within the intrinsic injury risk. Muscle functional magnetic resonance imaging (mfMRI) is one of the tools that has been proven to be valid for evaluating intermuscular coordination. Purpose: To investigate the risk of sustaining an index or recurring soccer-related hamstring injury by exploring metabolic muscle characteristics using mfMRI. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 27 healthy male soccer players and 27 soccer players with a history of hamstring injuries underwent standardized mfMRI. The mfMRI protocol consisted of a resting scan, a strenuous bilateral eccentric hamstring exercise, and a postexercise scan. The exercise-related T2 change, or the signal intensity shift between both scans, was used to detect differences in metabolic characteristics between (1) the different hamstring muscle bellies and (2) the prospective cohorts based on the (re)occurrence of hamstring injuries during a follow-up period of 18 months. Results: The risk of sustaining a first hamstring injury was associated with alterations in the intermuscular hierarchy in terms of the magnitude of the metabolic response after a heavy eccentric effort, with the dominant role of the semitendinosus set aside for a higher contribution of the biceps femoris (P = .017). Receiver operating characteristic (ROC) curve analysis demonstrated that this variable was significantly able to predict the occurrence of index injuries with a sensitivity of 100% and a specificity of 70% when the metabolic activity of the biceps femoris exceeded 10%. The risk of sustaining a reinjury was associated with a substantial deficit in hamstring strength endurance (P = .031). Soccer players who sustained a reinjury were only able to perform prone leg curls for a mean duration of 146.50 ± 76.16 seconds, whereas those with an injury history but no recurrence during follow-up were able to continue for a mean of 237.45 ± 110.76 seconds (95% CI, 11.9-230.5 seconds; P = .031). Conclusion: This was the first study to assess the causal relation between the intramuscular recruitment pattern and the risk of sustaining an index or secondary hamstring strain. Changes in intermuscular interplay seem to significantly increase the risk of sustaining index hamstring injuries in male amateur soccer players. Inadequate eccentric muscle endurance could be associated with an increased risk of sustaining a recurring hamstring injury.

The Effects of in-Season Repeated Sprint Training Compared to Regular Soccer Training.

The aim of this study was to compare the effects of repeated sprints (RSA) training and regular soccer training on Yo-Yo IR-1 and RSA performance (6 x 40 m shuttle sprints). Thirteen semi-professional female soccer players and nine amateur male soccer players were randomised into a repeated sprint group (RSG; n = 12) or a regular soccer training group (STG; n = 10). The RSG soccer players executed 3–4 sets of 4–6 repeated sprints (30 m with 180° directional changes) weekly during the last eight weeks of the in-season. In parallel, the STG soccer players performed low- to moderate intensity soccer training in form of technical or tactical skills. The RSG showed 15% improvement in Yo-Yo IR-1 (p = 0.04; ES = 1.83) and their mean RSA times were reduced by 1.5% (p = 0.02; ES = 0.89). No significant changes were found for the STG (Yo-Yo IR-1, p = 0.13; RSA, p = 0.49). Comparing the groups, greater improvements were observed in Yo-Yo IR-1 for the RSG (p = 0.02; ES = 1.15), but not for the RSA (p = 0.23; ES = −0.33). Similar training volumes and intensities (% of HFmax) were observed between the groups (p = 0.22 and p = 0.79). In conclusion, a weekly RSA session integrated into a regular soccer regime improved in-season RSA and Yo-Yo IR-1 performance compared to regular soccer training.

The Influence of Carbohydrate Mouth Rinse on Self-Selected Intermittent Running Performance.

This study investigated the influence of mouth rinsing a carbohydrate solution on self-selected intermittent variable-speed running performance. Eleven male amateur soccer players completed a modified version of the Loughborough Intermittent Shuttle Test (LIST) on 2 occasions separated by 1 wk. The modified LIST allowed the self-selection of running speeds during Block 6 of the protocol (75-90 min). Players rinsed and expectorated 25 ml of noncaloric placebo (PLA) or 10% maltodextrin solution (CHO) for 10 s, routinely during Block 6 of the LIST. Self-selected speeds during the walk and cruise phases of the LIST were similar between trials. Jogging speed was significantly faster during the CHO (11.3 ± 0.7 km · h(-1)) than during the PLA trial (10.5 ± 1.3 km · h(-1)) (p = .010); 15-m sprint speeds were not different between trials (PLA: 2.69 ± 0.18 s: CHO: 2.65 ± 0.13 s) (F(2, 10), p = .157), but significant benefits were observed for sprint distance covered (p = .024). The threshold for the smallest worthwhile change in sprint performance was set at 0.2 s. Inferential statistical analysis showed the chance that CHO mouth rinse was beneficial, negligible, or detrimental to repeated sprint performance was 86%, 10%, and 4%, respectively. In conclusion, mouth rinsing and expectorating a 10% maltodextrin solution was associated with a significant increase in self-selected jogging speed. Repeated 15-m sprint performance was also 86% likely to benefit from routinely mouth rinsing a carbohydrate solution in comparison with a taste-matched placebo.

Changes in Passive Tension of the Hamstring Muscles During a Simulated Soccer Match.

Passive muscle tension is increased after damaging eccentric exercise. Hamstring-strain injury is associated with damaging eccentric muscle actions, but no research has examined changes in hamstring passive muscle tension throughout a simulated sport activity. The authors measured hamstring passive tension throughout a 90-min simulated soccer match (SAFT90), including the warm-up period and every 15 min throughout the 90-min simulation. Passive hamstring tension of 15 amateur male soccer players was measured using the instrumented straight-leg-raise test. Absolute torque (Nm) and slope (Nm/°) of the recorded torque-angular position curve were used for data analysis, in addition to total leg range of motion (ROM). Players performed a 15-min prematch warm-up, then performed the SAFT90 including a 15-min halftime rest period. Reductions in passive stiffness of 20-50° of passive hip flexion of 22.1-29.2% (P < .05) were observed after the warm-up period. During the SAFT90, passive tension increased in the latter 20% of the range of motion of 10.1-10.9% (P < .05) concomitant to a 4.5% increase in total hamstring ROM (P = .0009). The findings of this study imply that hamstring passive tension is reduced after an active warm-up that includes dynamic stretching but does not increase in a pattern suggestive of eccentric induced muscle damage during soccer-specific intermittent exercise. Hamstring ROM and passive tension increases are best explained by improved stretch tolerance.

Measured and estimated energy cost of constant and shuttle running in soccer players.

Players in team sports like soccer often make acceleration and deceleration movements, which are more energetically demanding than running at constant speed. The first aim of the present study was to estimate this difference in associated energy cost. To this end, we compared the actual energy cost of shuttle running to that of running at constant speed. In addition, since measuring oxygen consumption is not feasible during soccer, the study's second aim was to determine the validity of an indirect approach to estimate energy cost provided by di Prampero et al. (2005) using time-motion data obtained from a tracking system as input. Fourteen male amateur soccer players performed aerobic constant and continuous shuttle running at six different speeds (range = 7.5-10.0 km·h⁻¹) on artificial turf. Measured energy cost was compared to the energy cost estimated with di Prampero's (2005) equation using data from a local position measurement (LPM) system as input. As expected, measured energy cost was significantly higher (∼30%-50%) for shuttle running than for constant running (P < 0.001), and this difference increased with speed. For constant running, estimated energy cost was significantly higher (6%-11%) than measured energy cost, whereas for shuttle running, estimated energy cost was significantly lower (-13% to -16%) than measured energy cost. Shuttle running raised the player's energy cost of running compared to constant running at the same average speed. Although actual energy cost of constant running was significantly overestimated by di Prampero's approach using LPM data as input, actual energy cost of shuttle running was significantly underestimated.

The Preventive Effect of the Nordic Hamstring Exercise on Hamstring Injuries in Amateur Soccer Players

Background: Hamstring injuries are the most common muscle injuries in soccer, and they have a high rate of recurrence. Eccentric hamstrings strength is recognized as an important modifiable risk factor. This led to the development of prevention exercises such as the nordic hamstring exercise (NHE). The effectiveness of the NHE on hamstring injury prevention has never been investigated in amateur soccer. Purpose: To investigate the preventive effect of the NHE on the incidence and severity of hamstring injuries in male amateur soccer players. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Male amateur soccer players (age, mean ± SD, 24.5 ± 3.8 years) from 40 teams were randomly allocated to an intervention (n = 20 teams, 292 players) or control group (n = 20 teams, 287 players). The intervention group was instructed to perform 25 sessions of NHE in a 13-week period. Both the intervention and control groups performed regular soccer training and were followed for hamstring injury incidence and severity during the 2013 calendar year. At baseline, personal characteristics (eg, age, injury history, field position) were gathered from all participants via a questionnaire. Primary outcome was injury incidence. Secondary outcomes were injury severity and compliance with the intervention protocol. Results: A total of 38 hamstring injuries were recorded, affecting 36 of 579 players (6.2%). The overall injury incidence rate was 0.7 (95% CI, 0.6-0.8) per 1000 player hours, 0.33 (95% CI, 0.25-0.46) in training, and 1.2 (95% CI, 0.82-1.94) in matches. Injury incidence rates were significantly different between the intervention (0.25; 95% CI, 0.19-0.35) and control groups (0.8; 95% CI, 0.61-1.15), χ2(1, n = 579) = 7.865; P = .005. The risk for hamstring injuries was reduced in the intervention group compared with the control group (odds ratio, 0.282; 95% CI, 0.110-0.721) and was statistically significant (P = .005). No statistically significant differences were identified between the intervention and control groups regarding injury severity. Compliance with the intervention protocol was 91%. Conclusion: Incorporating the NHE protocol in regular amateur training significantly reduces hamstring injury incidence, but it does not reduce hamstring injury severity. Compliance with the intervention was excellent.

Fatigue affects peak joint torque angle in hamstrings but not in quadriceps

Primary aim of this study was to investigate peak joint torque angle (i.e. the angle of peak torque) changes recorded during an isokinetic test before and after a fatiguing soccer match simulation. Secondarily we want to investigate functional Hecc:Qconc and conventional Hconc:Qconc ratio changes due to fatigue.Before and after a standardised soccer match simulation, twenty-two healthy male amateur soccer players performed maximal isokinetic strength tests both for hamstrings and for quadriceps muscles at 1.05 rad · s‒1, 3.14 rad · s‒1 and 5.24 rad · s‒1. Peak joint torque angle, peak torque and both functional Hecc:Qconc and conventional Hconc:Qconc ratios were examined. Both dominant and non-dominant limbs were tested.Peak joint torque angle significantly increased only in knee flexors. Both eccentric and concentric contractions resulted in such increment, which occurred in both limbs. No changes were found in quadriceps peak joint torque angle. Participants experienced a significant decrease in torque both in hamstrings and in quadriceps. Functional Hecc:Qconc ratio was lower only in dominant limb at higher velocities, while Hconc:Qconc did not change.This study showed after specific fatiguing task changes in hamstrings only torque/angle relationship. Hamstrings injury risk could depend on altered torque when knee is close to extension, coupled with a greater peak torque decrement compared to quadriceps. These results suggest the use eccentric based training to prevent hamstrings shift towards shorter length.