Male Semi-professional Soccer Players Research Articles

Physical Response to a Simulated Period of Soccer-Specific Fixture Congestion.

Page, RM, Marrin, K, Brogden, CM, and Greig, M. Physical response to a simulated period of soccer-specific fixture congestion. J Strength Cond Res 33(4): 1075-1085, 2019-The aim of this study was to assess the physiological, perceptual, and mechanical measures associated with the completion of a simulated period of short-term soccer-specific fixture congestion. Ten male semiprofessional soccer players completed 3 trials of a treadmill-based match simulation, with 48 hours interspersing each trial. A repeated measures general linear model identified significantly (p = 0.02) lower knee flexor peak torque (PT) recorded at 300°·s in the second (141.27 ± 28.51 N·m) and third trials (139.12 ± 26.23 N·m) when compared with the first trial (154.17 ± 35.25 N·m). Similarly, muscle soreness (MS) and PT data recorded at 60°·s were significantly (p ≤ 0.05) different in the third trial (MS = 42 ± 25 a.u; PT60 = 131.10 ± 35.38 N·m) when compared with the first trial (MS = 29 ± 29 a.u; PT60 = 145.61 ± 42.86 N·m). Significant (p = 0.003) differences were also observed for mean electromyography (EMGmean) of bicep femoris between the third trial (T0-15 = 126.36 ± 15.57 μV; T75-90 = 52.18 ± 17.19 μV) and corresponding time points in the first trial (T0-15 = 98.20 ± 23.49 μV; T75-90 = 99.97 ± 39.81 μV). Cumulative increases in perceived exertion, heart rate, oxygen consumption, blood lactate concentrations, EMGmean, and PlayerLoad (PL) were recorded across each trial. Muscle soreness and PT were also significantly different after trial. There were, however, no significant main effects or interactions for the salivary immunoglobulin A and the medial-lateral PL metrics. These data suggest a biomechanical and muscular emphasis with residual fatigue, with implications for injury risk and the development of recovery strategies.

Effects of Small-Sided Game Variation on Changes in Hamstring Strength.

Madison, G, Patterson, SD, Read, P, Howe, L, and Waldron, M. Effects of small-sided game variation on changes in hamstring strength. J Strength Cond Res 33(3): 839-845, 2019-Small-sided games (SSGs) are commonly used by soccer practitioners to condition players. This form of exercise can result in fatigue, potentially exposing the muscle to injury risk. The purpose of this study was to determine the effects of SSG variations on hamstring torque in semiprofessional soccer players. In a counterbalanced cross-over design, 10 male semiprofessional soccer players took part in both small relative area (3 vs. 3; 300 m) and large relative area (4 vs. 4; 1000 m) SSGs. The games comprised 6 × 4-minute bouts, with 90-second recovery. Both movement and heart rate responses were monitored by global positioning systems (GPS) and hamstring isometric torque was measured pre-training and post-training using a NordBord. There were differences (p < 0.05) between the small and large relative area games for peak hamstring force decrement (5.78 N and -13.62 N, respectively) and mean hamstring force decrement at 90° (11.11 N and -4.78 N, respectively). The number of accelerations was related to (r = 0.46, p = 0.039) reduced hamstring peak torque at 90°. In conclusion, larger relative area SSGs elicited the greatest internal and external loads, resulting in decrements in hamstring force. The number of accelerations performed in the session increases the likelihood of hamstring fatigue and can be controlled with the relative pitch area.

Brain changes depending on head impacts over one season of semi-professional soccer: A resting state functional magnetic resonance imaging study

Soccer is the most popular sport in the world, but soccer players are exposed to repetitive head impacts (RHI) when heading the ball. While heading is repeated thousands of times over a player's career, a possible brain cumulative effect might lead to neurodegenerative diseases. However, the lack of evidence explains the absence of prevention or protection for players. Our objective was to determine if playing soccer is associated with functional brain connectivity changes, depending on the exposure to RHI. In this longitudinal study, a cohort of 16 semi-professional male soccer players, aged between 18 and 26 years old, were recruited from 2 clubs in Bordeaux city which participating in a French regional championship. Twenty age-matched male controls without a concussion history and which don’t practice any contact sport were also recruited for comparison. Functional Magnetic Resonance Imaging (fMRI) data were acquired for both groups before and after the 2016–2017 soccer season. A follow-up of the exposure to RHI in soccer group was realized thanks to the video of the games. Soccer players demonstrated an increase of functional connectivity particularly between bilateral precentral region and fronto-temporal regions, in comparison with controls. Over the soccer play season, these increasing of functional connectivity was higher. The median of head impacts per player was 56 over the season, with no concussion. Exposure to RHI was associated with changes in functional connectivity between frontal and cerebellum regions. Our data demonstrate changes of multiple brain networks at the resting state in trained soccer players, with greater changes over one play season. RHI effect or training effect could be implicated. Other imaging modalities are required to study possible microstructural and microvascular anomalies post RHI in soccer.

The effects of short term detraining and retraining on physical fitness in elite soccer players

PurposeThe aim of this study was to examine the effects of aerobic high-intensity training with reduced volume and training cessation on body composition and physical fitness after the end of season and the time required to recapture physical fitness with intensified retraining following two weeks of detraining in elite soccer players.MethodTwenty male semi-professional soccer players participated in this study. The soccer players were assigned to either a group that completed high-intensity aerobic training (HAT, n = 10) or to a detraining and retraining group (DHAT, n = 10) for a 5-week period immediately after the end of the season. The first 2 weeks of the period, members of the HAT group performed high-intensity aerobic exercise (80–90% of HRmax, 12 min × 3, three times per week), whereas members of the DHAT group abstained from any physical activity. During the subsequent 3 weeks, members of both the HAT and DHAT groups completed high-intensity aerobic exercise. Exercise performance testing and body composition analysis were performed before; after 2 weeks of detraining; and at 1, 2 and 3 weeks of retraining.ResultsIntensified high-intensity training for 5 weeks maintained the performance in the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) and repeated sprints at any time point (P > 0.05). However 2 weeks of detraining resulted in significant decreases in the performance on the Yo-Yo IR2 (P < 0.01) and repeated sprints test (P < 0.05). Performance on the Yo-Yo IR2 enhanced after 2 weeks of retraining and was maintained up to 3 weeks after retraining, with no significant differences between conditions (P > 0.05). In addition, repeated sprint performance markedly decreased after the detraining period (P < 0.05) and was continuously lower compared to the baseline at 2 weeks after retraining (P < 0.05). Furthermore, this value reached baseline level at the end of the experimental period (P > 0.05). There were no significant differences between conditions in body composition, performance of agility, or sprint ability throughout the 5-week experimental period (P > 0.05).ConclusionsThe present data suggest that short-term detraining after the competitive season can markedly decrease performances in the Yo-Yo IR2 test and repeated sprints. To return to a previous level of ability on the Yo-Yo IR2 and/or sprint test with retraining through high-intensity aerobic training after a period of detraining, a similar or longer period of retraining is required. However, the high-intensity training with reduced amount of training after competitive season can prevent reductions in physical fitness.

Etiology and Recovery of Neuromuscular Fatigue following Competitive Soccer Match-Play.

Aim: Previous research into the etiology of neuromuscular fatigue following competitive soccer match-play has primarily focused on peripheral perturbations, with limited research assessing central nervous system function in the days post-match. The aim of the present study was to examine the contribution and time-course of recovery of central and peripheral factors toward neuromuscular fatigue following competitive soccer match-play.Methods: Sixteen male semi-professional soccer players completed a 90-min soccer match. Pre-, post- and at 24, 48, and 72 h participants completed a battery of neuromuscular, physical, and perceptual tests. Maximal voluntary contraction force (MVC) and twitch responses to electrical (femoral nerve) and transcranial magnetic stimulation (TMS) of the motor cortex during isometric knee-extension and at rest were measured to assess central nervous system (voluntary activation, VA) and muscle contractile (potentiated twitch force, Qtw, pot) function. Electromyography responses of the rectus femoris to single- and paired-pulse TMS were used to assess corticospinal excitability and short-interval intracortical inhibition (SICI), respectively. Fatigue and perceptions of muscle soreness were assessed via visual analog scales, and physical function was assessed through measures of jump (countermovement jump height and reactive strength index) and sprint performance.Results: Competitive match-play elicited significant post-match declines in MVC force (−14%, P < 0.001) that persisted for 48 h (−4%, P = 0.01), before recovering by 72 h post-exercise. VA (motor point stimulation) was reduced immediately post-match (−8%, P < 0.001), and remained depressed at 24 h (−5%, P = 0.01) before recovering by 48 h post-exercise. Qtw,pot was reduced post-match (−14%, P < 0.001), remained depressed at 24 h (−6%, P = 0.01), before recovering by 48 h post-exercise. No changes were evident in corticospinal excitability or SICI. Jump performance took 48 h to recover, while perceptions of fatigue persisted at 72 h.Conclusion: Competitive soccer match-play elicits substantial impairments in central nervous system and muscle function, requiring up to 48 h to resolve. The results of the study could have important implications for fixture scheduling, the optimal management of the training process, squad rotation during congested competitive schedules, and the implementation of appropriate recovery interventions.

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.​

Effects of Sesame (Sesamum indicum L.) Supplementation on Creatine Kinase, Lactate Dehydrogenase, Oxidative Stress Markers, and Aerobic Capacity in Semi-Professional Soccer Players.

Nutritional intervention with antioxidants rich foods has been considered a strategy to minimize the effects of overtraining in athletes. This experimental, randomized, and placebo-controlled study evaluated the effects of consumption of sesame (Sesamum indicum L.) on muscle damage markers, oxidative stress, systemic inflammation, and aerobic performance in male semi-professional soccer players. Twenty athletes were randomly assigned to groups that received 40 g (two tablespoons) per day of sesame or a placebo during 28 days of regular training (exposed to routine training that includes loads of heavy training in the final half of the season). Before and after intervention, creatine kinase (CK), lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), C-reactive protein (hs-CRP), and aerobic capacity were evaluated. Before intervention, a physiologic imbalance was noted in both groups related to CK and LDH levels. Sesame intake caused a reduction of CK (19%, p < 0.05), LDH (37%, p < 0.05), MDA (55%, p < 0.05) and hs-CRP (53%, p < 0.05) and increased SOD (14%, p < 0.05), vitamin A (25%, p < 0.05), and vitamin E (65%, p < 0.05) in the experimental group. These phenomena were accompanied by increased aerobic capacity (17%, p < 0.05). The placebo group showed an increase in CK (5%, p < 0.05) and no significant change in LDH, SOD or vitamin A. MDA levels decreased (21%, p < 0.05) and vitamin E increased (14%, p < 0.05) in the placebo group, but to a much lesser extent than in the experimental group. These results show that sesame consumption may reduce muscle damage and oxidative stress while improving the aerobic capacity in soccer players.

Non-targeted sportomics analyses by mass spectrometry to understand exercise-induced metabolic stress in soccer players

We have been using “-Omics” sciences with classic laboratory analyses to understand the systemic metabolic and signaling changes induced by sport and exercise. We called this approach Sportomics. Our samples were collected in situ either during competitions or training to mimic the genuine challenges and conditions faced during sports. Non-targeted analysis (NTA) has opened the door to a new era of high-throughput exercise-induced metabolic research. In the present study, 30 male semi-professional soccer players were observed for two subsequent days. Both blood and urine samples were collected immediately pre-match and after matches. The most up-regulated prominent molecules were fatty acyls, carboxylic acids and derivatives, steroids and steroid derivatives. The most down-regulated molecules were fatty acyls, carboxylic acids and derivatives, as well as benzene and substituted derivatives. After metabolite identification and determining which metabolites were up- or down-regulated, we took the metabolites and grouped them into classes to examine the metabolic pathways involved with purine metabolism and to investigate hyperammonemia. To follow-up on our findings in urine, we used point-of-care instrument analysis to measure capillary blood metabolites. Glucose significantly increased by 35%, whereas urate increased by 16% and uremia by 17% without any changes in creatinemia. In the present study, we showed that hypoxanthine and related metabolites were up-regulated in urine after a soccer match, which suggested that AMP deamination was increased. In this study, we demonstrated several results through urine non-target mass spectrometry (NTMS) to understand exercise-induced changes during a soccer match using a Sportomics approach. These data together demonstrated that during a soccer game, there was an increase in ATP use provided by ADP synthesis via myokinase. Our data may show that the use of urinary metabolomics can be a less invasive way to follow the metabolism of athletes during exercise. We demonstrated that the use of NTMS may be useful for future studies that aim to design holistic interventions for improving athletic performance.

Effects of knowing the task duration on players’ pacing patterns during soccer small-sided games

ABSTRACTThe aim of this study was to identify the influence of prior knowledge of exercise duration on players’ pacing patterns during soccer small-sided games. Twenty semi-professional male soccer players participated in this study. In the first game scenario, players were not informed how long they would be required to play the small-sided game and the activity was terminated after 20 min (Unknown Condition). In the second game scenario, players were told that they would play the small-sided game for 10 min, but immediately after completing the 10-min game, they were asked to complete another 10 min (Partially Condition). In the third game scenario, players were instructed that they would play the small-sided game for 20 min and then they completed the 20-min game (Known Condition). The results presented a tendency of higher values in all performance variables in the [0′–10′] min compared with the [10′–20′] min. As the players’ previous knowledge about the tasks duration increased, the performance between two moments tended to be similar. Considering the entire 20-min game duration, the Partially Condition of the exercise was the most demanding condition. In conclusion, the knowledge of shorter durations of the exercise seems to lead to an increase of exercise duration demand, and longer exercise durations possibly tend to decrease differences between full knowledge and not knowing the exercise duration.

The influence of different exercise intensities on kicking accuracy and velocity in soccer players

PurposeThe aim of this study was to investigate the influence of different exercise intensities induced by a soccer specific protocol on kicking performance in soccer players. MethodsTwelve semi-professional male soccer players participated in this study and performed maximal instep kicks before and after the implementation of an exercise protocol to determine the influence of different intensities upon kicking ball velocity and the target-hitting accuracy. ResultsAnalysis of variance designs with repeated measures showed that maximal ball velocity was affected only after the most intense circuit (F(6, 66) = 2.3; p = 0.041; η2 = 0.18), while accuracy was not affected in the protocol (F(6, 66) = 0.19; p = 0.98; η2 = 0.02). Low and moderate intensities did not affect accuracy or kicking ball velocity. ConclusionThese findings suggest that kicking ball velocity is influenced by high-exercise intensities. Low and moderate exercise intensities do not affect the performance of the kick, and intensity does not influence accuracy. Otherwise, it is possible that other mechanisms (not only physiological) may influence players during the exercise.

Reliability of the 30-15 Intermittent Fitness Test in Semiprofessional Soccer Players.

The purpose of this investigation was to determine the reliability of the 30-15 Intermittent Fitness Test (30-15(IFT)) in semiprofessional soccer players. Fourteen male semiprofessional soccer players performed the 30-1(IFT) on 2 occasions separated by 7 d. Reliability was assessed by intraclass correlation coefficient (ICC), typical error of measurement expressed as a coefficient of variation (CV), and smallest worthwhile change (SWC) to determine any significant difference between testing sessions. Maximal intermittent running velocity (V(IFT)) demonstrated good reliability (ICC = .80) for between-sessions reliability. The CV was 2.5% for between-sessions reliability of the 30-15(IFT). As the SWC (0.70 km/h) falls within the range in which the individual's true score is likely to lie (1.0 km/h), the usefulness of the VIFT was rated as marginal. Despite the usefulness of the 30-15(IFT) being deemed marginal, a change in performance as small as 1.0 km/h (2 stages) in V(IFT) could be considered substantial or real. This study demonstrates that V(IFT) in the 30-15(IFT) is reliable, resulting in a reliable assessment of team-sport-specific cardiorespiratory fitness, with changes as small as 1.0 km/h (2 stages) in V(IFT) considered meaningful.

The Relationship Between Intensity Indicators in Small-Sided Soccer Games.

The aim of the present study was to examine the relationship between different kinds of intensity indicators in small-sided soccer games. This descriptive correlational study included 14 semi-professional male soccer players (21.3 ± 2.3 years, 174 ± 4.0 cm, 73.4 ± 5.1 kg) from the same team. The players were monitored by means of heart rate monitors and GPS devices during 27 small-sided games of nine different formats, yielding a total of 217 recordings. After each game the Borg scale was used to give a rate of perceived exertion (RPE). The internal load indicators were the mean heart rate relative to the individual maximum (%HRmean) and the RPE, while those for the external load were the player load, total distance covered, distance covered in two intensity ranges (>18 km·h-1 and >21 km·h-1), and frequency of effort (in the same two intensity ranges). There was a significant moderate correlation (r=0.506) between the two internal load measurements (%HRmean and RPE). Although there were significant correlations of different degrees between various external load measurements, only the player load was significantly correlated with the internal load indicators (r=0.331 with %HRmean and r=0.218 with RPE). During training programes of this kind, it is necessary to consider a range of intensity indicators so as to obtain complementary information. This will enable coaches to more accurately assess the load imposed on players and therefore optimize the training process.

Angle-specific eccentric hamstring fatigue after simulated soccer.

To evaluate the effect of simulated soccer on the hamstrings eccentric torque-angle profile and angle of peak torque (APTeccH), and on the hamstrings:quadriceps torque ratio at specific joint angles (ASHecc:Qcon). The authors assessed dominant-limb isokinetic concentric and eccentric knee flexion and concentric knee extension at 120°/s in 9 semiprofessional male soccer players immediately before and after they completed the Loughborough Intermittent Shuttle Test (LIST). The LIST resulted in significant decreases in eccentric hamstrings torque at 60°, 50°, and 10° and a significant (21.8%) decrease in ASHecc:Qcon at 10° (P < .05). APTeccH increased from 7.1° ± 1.0° to 18.8° ± 4.2° (P < .05). Eccentric hamstrings peak torque significantly declined from 185.1 ± 70.4 N·m pre-LIST to 150.9 ± 58.5 N·m post-LIST (P = .002), but there were no significant changes in hamstrings or quadriceps concentric peak torque (P = .312, .169, respectively). Simulated soccer results in a selective loss of eccentric hamstrings torque and hamstrings-to-quadriceps muscle balance at an extended joint position and a shift in the eccentric hamstrings APT to a shorter length, changes that could increase vulnerability to hamstrings injury. These findings suggest that injury-risk screening could be improved by evaluating the eccentric hamstrings torque-angle profile and hamstrings strength-endurance and that the development of hamstrings fatigue resistance and long-length eccentric strength may reduce injury incidence.

Comparative study of the femoroacetabular impingement (FAI) prevalence in male semiprofessional and amateur soccer players

Femoroacetabular impingement (FAI) represents a novel approach to the mechanical etiology of hip osteoarthritis. The cam-type femoroacetabular impingement deformity occurs frequently in young male athletes. The aim of our study was to evaluate the prevalence of FAI in male semiprofessional soccer players using clinical examination and magnetic resonance imaging (MRI), compared to amateur soccer players. In MRI, the α angle of Nötzli is determined for quantifying FAI. According to power analysis, a total of 22 asymptomatic semiprofessional soccer players with a median of 23.3 years of age (range 18-30 years) and 22 male amateur soccer players with a median of 22.5 years of age (control group, range 18-29 years) underwent an MRI to measure the hip α angle of Nötzli. The α angle of the kicking legs of the semiprofessional group and the amateur group were analyzed. The study group was moreover evaluated by the Hip Outcome Score (HOS) and a clinical hip examination including range of motion (ROM) and impingement tests. In the semiprofessional group, 19 soccer players had a right kicking leg and 1 soccer player had a left kicking leg. 2 soccer players kicked with two feet. In the semi-professional group, the mean value of the α angle of the kicking leg (57.3 ± 8.2°) was significantly higher than in the amateur group (51.7 ± 4.8°, P = 0.008). In the semi-professional group, 15 (62.5 %) of 24 kicking legs had an increased α angle >55°, while 5 (27.3 %) kicking legs of the amateur group had an α angle >55°. Five semi professional soccer players had findings in clinical examination, whereof 4 had an increased α angle >55°. No participant of the amateur group showed pathological results in the clinical examination (P = 0.0484). Overall, semiprofessional soccer players had a higher proportion of an increased α angle than the amateur group. Semiprofessional players have a higher prevalence of an increased α angle in the kicking leg than the amateur group at the same age. The kicking leg is predisposed for FAI.

Biomechanical and functional indicators in male semiprofessional soccer players with increased hip alpha angles vs. amateur soccer players

BackgroundFemoroacetabular impingement (FAI) is predominant in young male athletes, but not much is known about gait differences in cases of increased hip alpha angles. In our study, the hip alpha angle of Nötzli of soccer players was quantified on the basis of magnetic resonance imaging (MRI) with axial oblique sequences. The aim of the current study was to compare the rearfoot motion and plantar pressure in male semiprofessional soccer players with increased alpha angles to age-matched amateur soccer players.MethodsIn a prospective analysis, male semiprofessional and amateur soccer players had an MRI of the right hip to measure the alpha angle of Nötzli. In a biomechanical laboratory setting, 14 of these participants in each group ran in two shoe conditions. Simultaneously in-shoe pressure distribution, tibial acceleration, and rearfoot motion measurements of the right foot were performed.ResultsIn the semiprofessional soccer group, the mean value of the alpha angle of group was 55.1 ± 6.58° (range 43.2-76.6°) and 51.6 ± 4.43° (range 41.9-58.8°) in the amateur group. In both shoe conditions, we found a significant difference between the two groups concerning the ground reaction forces, tibial acceleration, rearfoot motion and plantar pressure parameters (P < 0.01, P < 0.05, P = 0.04). Maximum rearfoot motion is about 22% lower in the semiprofessional group compared to the amateur group in both shoe conditions.ConclusionsThis study confirmed that semiprofessional soccer players with increased alpha angles showed differences in gait kinematics compared to the amateur group. These findings support the need for a screening program for competitive soccer players. In cases of a conspicuous gait analysis and symptomatic hip pain, FAI must be ruled out by further diagnostic tests.

An exploration of pre-performance routines, self-efficacy, anxiety and performance in semi-professional soccer

Whilst much research has suggested a positive link between pre-performance routines (PPRs) and performance, the specific mechanisms of the process have yet to be understood fully. It has been suggested that the PPR may influence performance through lowering the athlete's anxiety, and/or increasing their self-efficacy, but to date this has not specifically been explored in detail. As a result the aim of the current study was to explore the impact of specific individualised PPRs on performance, anxiety and self-efficacy in semi-professional soccer players. Participants were 20 male semi-professional soccer players (M = 19.45, SD = 2.81) recruited from clubs in England. Adopting a repeated measure design, players were tested on performance, anxiety, and self-efficacy pre- and post a 7-day intervention period in which the participants learnt a new PPR. The data were analysed using factorial mixed measures analysis of variance (ANOVAs), with the results revealing a significant difference in somatic anxiety for the experimental group and a decrease in performance for the control group. The study provides further support for the suggestion that the PPR can enhance performance by reducing experiences of anxiety prior to performance.

Progression of Mechanical Properties during On-field Sprint Running after Returning to Sports from a Hamstring Muscle Injury in Soccer Players

The objectives of this study were to examine the consequences of an acute hamstring injury on performance and mechanical properties of sprint-running at the time of returning to sports and after the subsequent ~2 months of regular soccer training after return. 28 semi-professional male soccer players, 14 with a recent history of unilateral hamstring injury and 14 without prior injury, participated in the study. All players performed two 50-m maximal sprints when cleared to return to play (Test 1), and 11 injured players performed the same sprint test about 2 months after returning to play (Test 2). Sprint performance (i. e., speed) was measured via a radar gun and used to derive linear horizontal force-velocity relationships from which the following variables obtained: theoretical maximal velocity (V(0)), horizontal force (F(H0)) and horizontal power (Pmax). Upon returning to sports the injured players were moderately slower compared to the uninjured players. F H0 and Pmax were also substantially lower in the injured players. At Test 2, the injured players showed a very likely increase in F(H0) and Pmax concomitant with improvements in early acceleration performance. Practitioners should consider assessing and training horizontal force production during sprint running after acute hamstring injuries in soccer players before they return to sports.

Influence of Game Format and Number of Players on Heart Rate Responses and Physical Demands in Small-Sided Soccer Games

The aim of the study was to examine the extent to which changing the game format (possession play vs. regulation goals and goalkeepers vs. small goals only) and the number of players (3 vs. 3, 5 vs. 5 and 7 vs. 7) influenced the physiological and physical demands of small-sided games (SSGs) in soccer in semiprofessional players. Fourteen semiprofessional male soccer players were monitored with global positioning system and heart rate devices. Heart rate, player load, distance covered, running speed, and the number of accelerations were recorded for 9 different SSGs. The results show that changes both in game format and the number of players affect the players' physiological and physical demands. Possession play places greater physiological and physical demands on players, although reducing the number of players only increases the physiological load. In the 7 vs. 7 games, changing the game format did not alter the heart rate responses. Finally, in the possession play format, changing the number of players did not produce significant differences in heart rate responses, although physical demands did decrease in line with a reduction in the number of players. These results should help coaches to understand how modifying different aspects of SSGs has a differential effect on the players' physiological and physical demands. Moreover, coaches in semiprofessional and amateur teams have now consistent information to design and optimize their training time in mixing the technical, tactical, and physical aspects.

Relationship Between Indicators of Training Load in Soccer Players

This study examined the relationship between work load indicators used to quantify full training sessions in soccer. The participants were 28 semiprofessional male soccer players age 22.9 ± 4.2 years, height 177 ± 5 cm, body mass 73.6 ± 4.4 kg. Players' physical and physiological work load was monitored over 44 training sessions using global positioning system devices (10 Hz) and heart rate, respectively. After each training session, players' training perceived-exertion (rating of perceived exertion [RPE]) was assessed using the Borg CR-10 scale. Players' internal training load was assessed using the session-RPE and the Edwards methods. Total distance, distances covered at arbitrary selected high-intensity speed zones (≥18 and 21 km·h(-1)), bout frequency at speed >18 and 21 km·h(-1), and work:rest ratio during training drills were considered as signs of physical work load. Furthermore, player load assumed as reflection of total center-of-mass acceleration was considered as representative of players' external load. Very-large association of player load with Edwards and session-RPE methods was found. Total distance covered was large to very large associated with Player Load, Session-RPE, and Edwards methods. The findings of this study provided evidence for the safe use of session-RPE, Edwards methods, and Players Load as valid indicators of training responses in soccer.

Money in – brains out? Institutional logics affecting athletes’ preparation for alternative careers

Competitive sport encourages athletes to put all their effort into excelling in their sport despite the fact that sport careers are short and can be abruptly terminated. This study addresses the issue of dual career preparation among team sport athletes in a sample comprising Norwegian full-professional male soccer players and semi-professional soccer and handball players. Professional athletes hardly spend more time on their sport than do semi-professional top players, but while the latter group of athletes combine sports careers and higher education (or work), professional players tend to spend their leisure time more with family and friends. A competing institutional logics approach is utilised to analyse the data and reflect on social influences on athletes’ choice of career preparation.