Objective To investigate whether a neuromuscular training programme is effective in preventing non-contact leg injuries in female floorball players.
Design Cluster randomised controlled study.
Setting 28 top level female floorball teams in Finland.
Participants 457 players (mean age 24 years)—256 (14 teams) in the intervention group and 201 (14 teams) in the control group—followedup for one league season (six months).
Intervention A neuromuscular training programme to enhance players’ motor skills and body control, as well as to activate and prepare their neuromuscular system for sports specific manoeuvres.
Main outcome measure Acute non-contact injuries of the legs.
Results During the season, 72 acute non-contact leg injuries occurred, 20 in the intervention group and 52 in the control group. The injury incidence per 1000 hours playing and practise in the intervention group was 0.65 (95% confidence interval 0.37 to 1.13) and in the control group was 2.08 (1.58 to 2.72). The risk of non-contact leg injury was 66% lower (adjusted incidence rate ratio 0.34, 95% confidence interval 0.20 to 0.57) in the intervention group.
Conclusion A neuromuscular training programme was effective in preventing acute non-contact injuries of the legs in female floorball players. Neuromuscular training can be recommended in the weekly training of these athletes.
Trial registration Current Controlled Trials ISRCTN26550281.
Objective To examine the effect of a comprehensive warm-up programme designed to reduce the risk of injuries in female youth football.
Design Cluster randomised controlled trial with clubs as the unit of randomisation.
Setting 125 football clubs from the south, east, and middle of Norway (65 clusters in the intervention group; 60 in the control group) followed for one league season (eight months).
Participants 1892 female players aged 13-17 (1055 players in the intervention group; 837 players in the control group).
Intervention A comprehensive warm-up programme to improve strength, awareness, and neuromuscular control during static and dynamic movements.
Main outcome measure Injuries to the lower extremity (foot, ankle, lower leg, knee, thigh, groin, and hip).
Results During one season, 264 players had relevant injuries: 121 players in the intervention group and 143 in the control group (rate ratio 0.71, 95% confidence interval 0.49 to 1.03). In the intervention group there was a significantly lower risk of injuries overall (0.68, 0.48 to 0.98), overuse injuries (0.47, 0.26 to 0.85), and severe injuries (0.55, 0.36 to 0.83).
Conclusion Though the primary outcome of reduction in lower extremity injury did not reach significance, the risk of severe injuries, overuse injuries, and injuries overall was reduced. This indicates that a structured warm-up programme can prevent injuries in young female football players.
Trial registration ISRCTN10306290.
Objective To investigate the effect of a structured warm-up programme designed to reduce the incidence of knee and ankle injuries in young people participating in sports.
Design Cluster randomised controlled trial with clubs as the unit of randomisation.
Setting 120 team handball clubs from central and eastern Norway (61 clubs in the intervention group, 59 in the control group) followed for one league season (eight months).
Participants 1837 players aged 15-17 years; 958 players (808 female and 150 male) in the intervention group; 879 players (778 female and 101 male) in the control group.
Intervention A structured warm-up programme to improve running, cutting, and landing technique as well as neuromuscular control, balance, and strength.
Main outcome measure The rate of acute injuries to the knee or ankle.
Results During the season, 129 acute knee or ankle injuries occurred, 81 injuries in the control group (0.9 (SE 0.09) injuries per 1000 player hours; 0.3 (SE 0.17) in training v 5.3 (SE 0.06) during matches) and 48 injuries in the intervention group (0.5 (SE 0.11) injuries per 1000 player hours; 0.2 (SE 0.18) in training v 2.5 (SE 0.06) during matches). Fewer injured players were in the intervention group than in the control group (46 (4.8%) v (76 (8.6%); relative risk intervention group v control group 0.53, 95% confidence interval 0.35 to 0.81).
Conclusion A structured programme of warm-up exercises can prevent knee and ankle injuries in young people playing sports. Preventive training should therefore be introduced as an integral part of youth sports programmes.
Objective To evaluate the effectiveness of neuromuscular training in reducing the rate of acute knee injury in adolescent female football players.
Design Stratified cluster randomised controlled trial with clubs as the unit of randomisation.
Setting 230 Swedish football clubs (121 in the intervention group, 109 in the control group) were followed for one season (2009, seven months).
Participants 4564 players aged 12-17 years (2479 in the intervention group, 2085 in the control group) completed the study.
Intervention 15 minute neuromuscular warm-up programme (targeting core stability, balance, and proper knee alignment) to be carried out twice a week throughout the season.
Main outcome measures The primary outcome was rate of anterior cruciate ligament injury; secondary outcomes were rates of severe knee injury (>4 weeks’ absence) and any acute knee injury.
Results Seven players (0.28%) in the intervention group, and 14 (0.67%) in the control group had an anterior cruciate ligament injury. By Cox regression analysis according to intention to treat, a 64% reduction in the rate of anterior cruciate ligament injury was seen in the intervention group (rate ratio 0.36, 95% confidence interval 0.15 to 0.85). The absolute rate difference was −0.07 (95% confidence interval −0.13 to 0.001) per 1000 playing hours in favour of the intervention group. No significant rate reductions were seen for secondary outcomes.
Conclusions A neuromuscular warm-up programme significantly reduced the rate of anterior cruciate ligament injury in adolescent female football players. However, the absolute rate difference did not reach statistical significance, possibly owing to the small number of events.
Trial registration Clinical trials NCT00894595.
The incidence rate of soccer injuries is among the highest in sports, particularly for adult male soccer players.
To investigate the effect of the ‘The11’ injury prevention programme on injury incidence and injury severity in adult male amateur soccer players.
Cluster-randomised controlled trial.
Teams from two high-level amateur soccer competitions were randomly assigned to an intervention (n=11 teams, 223 players) or control group (n=12 teams, 233 players). The intervention group was instructed to perform The11 in each practice session during one soccer season. The11 focuses on core stability, eccentric training of thigh muscles, proprioceptive training, dynamic stabilisation and plyometrics with straight leg alignment. All participants of the control group continued their practice sessions as usual.
In total, 427 injuries were recorded, affecting 274 of 456 players (60.1%). Compliance with the intervention programme was good (team compliance=73%, player compliance=71%). Contrary to the hypothesis, injury incidences were almost equal between the two study groups: 9.6 per 1000 sports hours (8.4–11.0) for the intervention group and 9.7 (8.5–11.1) for the control group. No significant differences were found in injury severity, but a significant difference was observed in the location of the injuries: players in the intervention group sustained significantly less knee injuries.
This study did not find significant differences in the overall injury incidence or injury severity between the intervention and control group of adult male soccer players. More research is recommended, focusing on injury aetiology and risk factors in adult male amateur soccer players.
Knee injuries in football are common regardless of age, gender or playing level, but adolescent females seem to have the highest risk. The consequences after severe knee injury, for example anterior cruciate ligament (ACL) injury, are well-known, but less is known about knee injury prevention. We have designed a cluster randomized controlled trial (RCT) to evaluate the effect of a warm-up program aimed at preventing acute knee injury in adolescent female football.
In this cluster randomized trial 516 teams (309 clusters) in eight regional football districts in Sweden with female players aged 13–17 years were randomized into an intervention group (260 teams) or a control group (256 teams). The teams in the intervention group were instructed to do a structured warm-up program at two training sessions per week throughout the 2009 competitive season (April to October) and those in the control group were informed to train and play as usual. Sixty-eight sports physical therapists are assigned to the clubs to assist both groups in data collection and to examine the players' acute knee injuries during the study period. Three different forms are used in the trial: (1) baseline player data form collected at the start of the trial, (2) computer-based registration form collected every month, on which one of the coaches/team leaders documents individual player exposure, and (3) injury report form on which the study therapists report acute knee injuries resulting in time loss from training or match play. The primary outcome is the incidence of ACL injury and the secondary outcomes are the incidence of any acute knee injury (except contusion) and incidence of severe knee injury (defined as injury resulting in absence of more than 4 weeks). Outcome measures are assessed after the end of the 2009 season.
Prevention of knee injury is beneficial for players, clubs, insurance companies, and society. If the warm-up program is proven to be effective in reducing the incidence of knee injury, it can have a major impact by reducing the future knee injury burden in female football as well as the negative long-term disabilities associated with knee injury.
To evaluate the effectiveness of a preseason physical training programme that taught landing and falling skills in improving landing skills technique and preventing injury in junior elite Australian football players.
723 male players who participated in an under 18 elite competition were studied prospectively in a non‐randomised controlled trial over two consecutive football seasons. There were 114 players in the intervention group and 609 control players. The eight session intervention programme taught players six landing, falling, and recovery skills, which were considered fundamental for safe landing in Australian football. Landing skills taught in these sessions were rated for competence by independent and blinded assessors at baseline and mid‐season.
Evaluation of landing skills found no significant differences between the groups at baseline. Evaluation after the intervention revealed overall improvement in landing skills, but significantly greater improvement in the intervention group (z = −7.92, p = 0.001). Players in the intervention group were significantly less likely (relative rate 0.72, 95% confidence interval 0.52 to 0.98) to sustain an injury during the season than the control group. In particular, the time to sustaining a landing injury was significantly less for the intervention group (relative rate 0.40, 95% confidence interval 0.17 to 0.92) compared with the control group.
Landing and falling ability can be taught to junior elite Australian football players. Players in the intervention group were protected against injury, particularly injuries related to landing and falls.
injury; Australian football; prevention; intervention; landing
Background and aims
Approximately 16% of all sports injuries in the Netherlands are caused by outdoor soccer. A cluster-randomised controlled trial has been designed to investigate the effectiveness and cost-effectiveness of an injury prevention programme (‘The11’) for male amateur soccer players. The injury prevention programme The11, developed with the support of the World Football Association FIFA, aims to reduce the impact of intrinsic injury risk factors in soccer.
Teams playing at first-class amateur level in two districts in the Netherlands are participating in the study. Teams in the intervention group were instructed to apply The11 during each practice session throughout the 2009–10 season. All participants of the control group continued their practice sessions as usual. All soccer-related injuries and related costs for each team were systematically reported online by a member of the medical staff. Player exposure to practice sessions and matches was reported weekly by the coaches. Also the use of The11 during the season after the intervention season will be monitored.
Our hypothesis is that integrating the The11 exercises in the warm-up for each practice session is effective in terms of injury incidence, injury severity, healthcare use, and its associated costs and/or absenteeism. Prevention of soccer injuries is expected to be beneficial to adult soccer players, soccer clubs, the Royal Dutch Football Association (KNVB), health insurance companies and society.
Soccer; injuries; prevention; effectiveness; cost-effectiveness; economics; methods; program; sports
Objective: Head/orofacial (H/O) injuries are common in Australian rules football. Mouthguards are widely promoted to prevent these injuries, in spite of the lack of formal evidence for their effectiveness.
Design: The Australian football injury prevention project was a cluster randomized controlled trial to evaluate the effectiveness of mouthguards for preventing H/O injuries in these players.
Setting and subjects: Twenty three teams (301 players) were recruited from the largest community football league in Australia.
Intervention: Teams were randomly allocated to either the MG: custom made mouthguard or C: control (usual mouthguard behaviours) study arm.
Main outcome measures: All injuries, participation in training and games, and mouthguard use were monitored over the 2001 playing season. Injury rates were calculated as the number of injuries per 1000 person hours of playing time. Adjusted incidence rate ratios were obtained from Poisson regression models.
Results: Players in both study arms wore mouthguards, though it is unlikely that many controls wore custom made ones. Wearing rates were higher during games than training. The overall rate of H/O injury was 2.7 injuries per 1000 exposure hours. The rate of H/O injury was higher during games than training. The adjusted H/O injury incidence rate ratio was 0.56 (95% CI 0.32 to 0.97) for MG versus C during games and training, combined.
Conclusions: There was a significant protective effect of custom made mouthguards, relative to usual mouthguard use, during games. However, the control players still wore mouthguards throughout the majority of games and this could have diluted the effect.
Background: Ankle sprains are the most common form of acute injury in volleyball. A prevention programme consisting of technical training, proprioceptive training, and external support was previously designed to reduce the rate of ankle sprains in volleyball players.
Objective: To investigate which of these three interventions is the most effective in preventing ankle sprain in female volleyball players.
Methods: Participants were 52 players who suffered ankle sprains during the season 1998–1999. They were divided randomly into three preventive groups: group 1 (n = 18) followed the technical training programme; group 2 (n = 17) followed the proprioceptive programme; group 3 (n = 17) used orthosis. The players followed their respective programmes for the whole of the 1999–2000 season. Data were collected at the end of the season.
Results: The three preventive strategies were all effective in preventive further ankle sprain. Technical training was slightly more effective than the other two methods. Orthosis was not effective in athletes who had suffered ankle sprains more than three times during their careers. Under those circumstances, technical training and proprioceptive training were equally effective at preventive further sprains.
Conclusions: Technical training and proprioceptive training are effective methods of preventing ankle sprain in volleyball players who have suffered this injury four or more times during their career. Orthosis appears effective only in players with fewer than four previous sprains.
Objectives: To evaluate the cost effectiveness of a proprioceptive balance board training programme for the prevention of ankle sprains in volleyball.
Methods: A total of 116 volleyball teams participated in this study which was carried out during the 2001–2002 volleyball season. Teams were randomly allotted to an intervention group (66 teams, 628 players) or a control group (52 teams, 494 players). Intervention teams followed a prescribed balance board training programme as part of their warm up. Control teams followed their normal training routine. An ankle sprain was recorded if it occurred as a result of volleyball and caused the subject to stop volleyball activity. The injured player completed a cost diary for the duration of the ankle sprain. Analyses were performed according to the intention to treat principle. Mean direct, indirect, and total costs were calculated and were compared between the two groups.
Results: The total costs per player (including the intervention material) were significantly higher in the intervention group (€36.99 (93.87)) than in the control group (€18.94 (147.09)). The cost of preventing one ankle sprain was approximately €444.03. Sensitivity analysis showed that a proprioceptive balance board training programme aimed only at players with previous ankle sprains could be cost effective over a longer period of time.
Conclusions: Positive effects of the balance board programme could only be achieved at certain costs. However, if broadly implemented, costs associated with the balance board programme would probably be lower.
Background: The Australian football injury prevention project (AFIPP) was a randomised controlled trial examining the effects of protective equipment on injury rates in Australian Football.
Objective: To present the results of the AFIPP baseline survey of community football players' attitudes towards protective equipment.
Methods: Teams of players were recruited from the largest community football league in Victoria, Australia, during the 2001 playing season; 301 players were enrolled in the study and all were surveyed before the season began about their attitudes towards protective headgear and mouthguards.
Results: Almost three quarters of the players (73.6%) reported wearing mouthguards during the previous playing season (year 2000) compared with only 2.1% wearing headgear. The most common reasons for not wearing headgear and mouthguards (in non-users) were: "I don't like wearing it" (headgear: 44.8%; mouthguards: 30.6%), and "It is too uncomfortable" (headgear: 40.7%; mouthguards: 45.8%).
Conclusions: The higher mouthguard usage reflects the favourable attitudes towards mouthguards by Australian football players generally. Similarly, the low headgear usage reflects the low acceptance of this form of protection in this sport. Further research should be directed towards establishing the reasons why players seem to believe that headgear plays a role in injury prevention yet few wear it.
Controlled cohort repeated-measures experimental design.
To determine if a neuromuscular training program (NMTP) focused on core stability and lower extremity strength would affect performance on the star excursion balance test (SEBT). We hypothesized that NMTP would improve SEBT performance in the experimental group and there would be no side-to-side differences in either group.
The SEBT is a functional screening tool that is used to assess dynamic stability, monitor rehabilitation progress, assess deficits following an injury, and identify athletes at high risk for lower extremity injury. The SEBT requires lower extremity coordination, balance, flexibility, and strength.
Twenty uninjured female soccer players (13 experimental, 7 control) participated. Players trained together as a team, so group allocation was not randomized. The SEBT was administered prior to and following 8 weeks of NMTP in the experimental group and 8 weeks of no NMTP in the control group. A 3-way mixed-model ANOVA was used to determine the effect of group (experimental versus control), training (pretraining versus posttraining), and limb (right versus left).
After participation in a NMTP, subjects demonstrated a significant improvement in the SEBT composite score (mean ± SD) on the right limb (pretraining, 96.4% ± 11.7%; posttraining, 104.6% ± 6.1%; P = .03) and the left limb (pretraining, 96.9% ± 10.1%; posttraining, 103.4% ± 8.0%; P = .04). The control group had no change on the SEBT composite score for the right (pretraining, 95.7% ± 5.2%; posttraining, 94.4% ± 5.2%; P = .15) or the left (97.4% ± 7.2%; 93.6% ± 5.0%; P = .09) limb. Further analysis identified significant improvement for the SEBT in the posterolateral direction on both the right (P = .008) and left (P = .040) limb and the posteromedial direction of the left limb (P = .028) in the experimental group.
Female soccer players demonstrated an improved performance on the SEBT after NMTP that focused on core stability and lower extremity strength.
LEVEL OF EVIDENCE
Performance enhancement, level 2b-.
core stability; core strengthening; injury prevention training; trunk neuromuscular control
To describe risk factors for injuries in elite female soccer.
A total of 143 female soccer players from the German national league participated in the study. Baseline information on player characteristics—for example, anthropometric measurements and playing position—and medical history were recorded at the start of the study. During one outdoor season, injuries and training and match exposure times were prospectively documented for each player.
The risk of a new anterior cruciate ligament (ACL) rupture was significantly increased in players with a previous rupture (odds ratio (OR) = 5.24, p = 0.01). This was not the case for ankle sprain (OR = 1.39) or knee sprain (OR = 1.50). In addition, no significantly increased risk of new sprains or ACL ruptures was found when the injured leg was the unit of analysis. Injury incidence was considerably higher in defenders (9.4 injuries per 1000 hours exposure) and strikers (8.4/1000 hours) than goalkeepers (4.8/1000 hours) and midfielders (4.6/1000 hours). Ten per cent of all players (n = 14) sustained more than three injuries. Most of these were defenders (n = 8) or strikers (n = 4). Significantly more injuries occurred to the dominant leg (105 v 71, p = 0.01); this was particularly true for contact injuries (52 v 29, p = 0.01).
Injury risk should be assessed on an individual basis. Therefore it seems appropriate to individualise preventive training programmes, as is recommended for other training content. Evaluating the existing rules of soccer and their appropriate application may also help to decrease injury risk, particularly in contact situations.
epidemiology; prospective cohort study; women; football; injury risk factors
Goals—To assess the relative injury reduction effect and acceptability of face guards on batter's helmets.
Methods—A non-randomized prospective cohort study among 238 youth league baseball teams in Central and Southern Indiana during the 1997 season. Coaches, parents, and players were asked to respond to pre-season and post-season questionnaires. Approximately one half of the teams were supplied with face guard helmets (intervention); all others used this protection at their discretion (comparison).
Results—Parents, players, and coaches on the intervention teams reported a reduction in the incidence of oculofacial injuries compared with comparison team respondents (p=0.04). There was no reported adverse effect of face guard use on player performance.
Conclusions—Helmet face guards should be required for batters to prevent facial injuries in baseball.
Improving neuromuscular control of hamstrings muscles might have implications for decreasing anterior cruciate ligament injuries in females.
To examine the effects of a 6-week agility training program on quadriceps and hamstrings muscle activation, knee flexion angles, and peak vertical ground reaction force.
Prospective, randomized clinical research trial.
Sports medicine research laboratory.
Patients or Other Participants:
Thirty female intramural basketball players with no history of knee injury (age = 21.07 ± 2.82 years, height = 171.27 ± 4.66 cm, mass = 66.36 ± 7.41 kg).
Participants were assigned to an agility training group or a control group that did not participate in agility training. Participants in the agility training group trained 4 times per week for 6 weeks.
Main Outcome Measure(s):
We used surface electromyography to assess muscle activation for the rectus femoris, vastus medialis oblique, medial hamstrings, and lateral hamstrings for 50 milliseconds before initial ground contact and while the foot was in contact with the ground during a side-step pivot maneuver. Knee flexion angles (at initial ground contact, maximum knee flexion, knee flexion displacement) and peak vertical ground reaction force also were assessed during this maneuver.
Participants in the training group increased medial hamstrings activation during ground contact after the 6-week agility training program. Both groups decreased their vastus medialis oblique muscle activation during ground contact. Knee flexion angles and peak vertical ground reaction force did not change for either group.
Agility training improved medial hamstrings activity in female intramural basketball players during a side-step pivot maneuver. Agility training that improves hamstrings activity might have implications for reducing anterior cruciate ligament sprain injury associated with side-step pivots.
anterior cruciate ligament; injury prevention; knee sprains
Methods: During the preseason, 10 Australian football clubs volunteered 23 teams to participate in a protective equipment randomised controlled trial, the Australian Football Injury Prevention Project (AFIPP). All players from these teams were invited to participate. Players who did not agree to participate in AFIPP were surveyed about their reasons for non-involvement.
Results: 110 football players (response rate 63.6%) completed the non-responder survey and cited the two main reasons behind non-involvement in the project as "I did not know about the project" (39.4%) and "I was not at training when the research team visited" (36.5%).
Conclusions and implications: Preseason may not be the best time for maximal player recruitment in community based sports safety research. Enhanced communication between researchers and players at community level football clubs during the recruitment phase is likely to improve response rates.
The rapidly increasing number of activity-induced musculoskeletal injuries among adolescents and young adults is currently a true public health burden. The objective of this study was to investigate whether a neuromuscular training programme with injury prevention counselling is effective in preventing acute musculoskeletal injuries in young men during military service.
The trial design was a population-based, randomised study. Two successive cohorts of male conscripts in four companies of one brigade in the Finnish Defence Forces were first followed prospectively for one 6-month term to determine the baseline incidence of injury. After this period, two new successive cohorts in the same four companies were randomised into two groups and followed prospectively for 6 months. Military service is compulsory for about 90% of 19-year-old Finnish men annually, who comprised the cohort in this study. This randomised, controlled trial included 968 conscripts comprising 501 conscripts in the intervention group and 467 conscripts in the control group. A neuromuscular training programme was used to enhance conscripts' motor skills and body control, and an educational injury prevention programme was used to increase knowledge and awareness of acute musculoskeletal injuries. The main outcome measures were acute injuries of the lower and upper limbs.
In the intervention groups, the risk for acute ankle injury decreased significantly compared to control groups (adjusted hazards ratio (HR) = 0.34, 95% confidence interval (95% CI) = 0.15 to 0.78, P = 0.011). This risk decline was observed in conscripts with low as well as moderate to high baseline fitness levels. In the latter group of conscripts, the risk of upper-extremity injuries also decreased significantly (adjusted HR = 0.37, 95% CI 0.14 to 0.99, P = 0.047). In addition, the intervention groups tended to have less time loss due to injuries (adjusted HR = 0.55, 95% CI 0.29 to 1.04).
A neuromuscular training and injury prevention counselling programme was effective in preventing acute ankle and upper-extremity injuries in young male army conscripts. A similar programme could be useful for all young individuals by initiating a regular exercise routine.
ClinicalTrials.gov identifier number NCT00595816.
Objective To evaluate the effectiveness of an unsupervised proprioceptive training programme on recurrences of ankle sprain after usual care in athletes who had sustained an acute sports related injury to the lateral ankle ligament.
Design Randomised controlled trial, with one year follow-up.
Setting Primary care.
Participants 522 athletes, aged 12-70, who had sustained a lateral ankle sprain up to two months before inclusion; 256 (120 female and 136 male) in the intervention group; 266 (128 female and 138 male) in the control group.
Intervention Both groups received treatment according to usual care. Athletes allocated to the intervention group additionally received an eight week home based proprioceptive training programme.
Main outcome measure Self reported recurrence of ankle sprain.
Results During the one year follow-up, 145 athletes reported a recurrent ankle sprain: 56 (22%) in the intervention group and 89 (33%) in the control group. Nine athletes needed to be treated to prevent one recurrence (number needed to treat). The intervention programme was associated with a 35% reduction in risk of recurrence. Cox regression analysis showed significantly fewer recurrent ankle sprains in the intervention than in the control group. This effect was found for self reported recurrent ankle sprains (relative risk 0.63, 95% confidence interval 0.45 to 0.88), recurrent ankle sprains leading to loss of sports time (0.53, 0.32 to 0.88), and recurrent ankle sprains resulting in healthcare costs or lost productivity costs (0.25, 0.12 to 0.50). No significant differences were found between medically treated athletes in the intervention group and medically treated controls. Athletes in the intervention group who were not medically treated had a significantly lower risk of recurrence than controls who were not medically treated.
Conclusions The use of a proprioceptive training programme after usual care of an ankle sprain is effective for the prevention of self reported recurrences. This proprioceptive training was specifically beneficial in athletes whose original sprain was not medically treated.
Trial registration ISTRCN34177180
The aim of the present study was to investigate the effects of a short-term in-season plyometric training program on power, agility and knee extensor strength. Male soccer players from a third league team were assigned into an experimental and a control group. The experimental group, beside its regular soccer training sessions, performed a periodized plyometric training program for six weeks. The program included two training sessions per week, and maximal intensity unilateral and bilateral plyometric exercises (total of 40 – 100 foot contacts/session) were executed. Controls participated only in the same soccer training routine, and did not perform plyometrics. Depth vertical jump height, agility (Illinois Agility Test, T Agility Test) and maximal voluntary isometric torque in knee extensors using Multicont II dynamometer were evaluated before and after the experiment. In the experimental group small but significant improvements were found in both agility tests, while depth jump height and isometric torque increments were greater. The control group did not improve in any of the measures. Results of the study indicate that plyometric training consisting of high impact unilateral and bilateral exercises induced remarkable improvements in lower extremity power and maximal knee extensor strength, and smaller improvements in soccer-specific agility. Therefore, it is concluded that short-term plyometric training should be incorporated in the in-season preparation of lower level players to improve specific performance in soccer.
knee extensors; depth jump; dynamometer; unilateral; plyometrics
Altered neuromuscular control strategies during fatigue probably contribute to the increased incidence of non-contact anterior cruciate ligament injuries in female athletes.
To determine biomechanical differences between 2 fatigue protocols (slow linear oxidative fatigue protocol [SLO-FP] and functional agility short-term fatigue protocol [FAST-FP]) when performing a running-stop-jump task.
Controlled laboratory study.
Patients or Other Participants:
A convenience sample of 15 female soccer players (age = 19.2 ±0.8 years, height = 1.67±0.05m, mass = 61.7 + 8.1 kg) without injury participated.
Five successful trials of a running–stop-jump task were obtained prefatigue and postfatigue during the 2 protocols. For the SLO-FP, a peak oxygen consumption (V˙o2peak) test was conducted before the fatigue protocol. Five minutes after the conclusion of the V˙o2peak test, participants started the fatigue protocol by performing a 30-minute interval run. The FAST-FP consisted of 4 sets of a functional circuit. Repeated 2 (fatigue protocol) × 2 (time) analyses of variance were conducted to assess differences between the 2 protocols and time (prefatigue, postfatigue).
Main Outcome Measure(s):
Kinematic and kinetic measures of the hip and knee were obtained at different times while participants performed both protocols during prefatigue and postfatigue.
Internal adduction moment at initial contact (IC) was greater during FAST-FP (0.064 ±0.09 Nm/kgm) than SLO-FP (0.024±0.06 Nm/kgm) (F1,14 = 5.610, P=.03). At IC, participants had less hip flexion postfatigue (44.7°±8.1°) than prefatigue (50.1°±9.5°) (F1,14 = 16.229, P=.001). At peak vertical ground reaction force, participants had less hip flexion postfatigue (44.7°±8.4°) than prefatigue (50.4°±10.3°) (F1,14 = 17.026, P=.001). At peak vertical ground reaction force, participants had less knee flexion postfatigue (−35.9°±6.5°) than prefatigue (−38.8°±5.03°) (F1,14 = 11.537, P=.001).
Our results demonstrated a more erect landing posture due to a decrease in hip and knee flexion angles in the postfatigue condition. The changes were similar between protocols; however, the FAST-FP was a clinically applicable 5-minute protocol, whereas the SLO-FP lasted approximately 45 minutes.
anterior cruciate ligament; hip; knee; biomechanics
To compare injury risk in elite football played on artificial turf compared with natural grass.
Prospective two‐cohort study.
Male European elite football leagues.
290 players from 10 elite European clubs that had installed third‐generation artificial turf surfaces in 2003–4, and 202 players from the Swedish Premier League acting as a control group.
Main outcome measure
The incidence of injury during training and match play did not differ between surfaces for the teams in the artificial turf cohort: 2.42 v 2.94 injuries/1000 training hours and 19.60 v 21.48 injuries/1000 match hours for artificial turf and grass respectively. The risk of ankle sprain was increased in matches on artificial turf compared with grass (4.83 v 2.66 injuries/1000 match hours; rate ratio 1.81, 95% confidence interval 1.00 to 3.28). No difference in injury severity was seen between surfaces. Compared with the control cohort who played home games on natural grass, teams in the artificial turf cohort had a lower injury incidence during match play (15.26 v 23.08 injuries/1000 match hours; rate ratio 0.66, 95% confidence interval 0.48 to 0.91).
No evidence of a greater risk of injury was found when football was played on artificial turf compared with natural grass. The higher incidence of ankle sprain on artificial turf warrants further attention, although this result should be interpreted with caution as the number of ankle sprains was low.
injuries; football; surface properties; soccer; artificial turf
Objective: To evaluate stress fractures in leg (particularly around the knee, tibia, and femur) and knee pathology in active asymptomatic (no symptoms in the preceding month) soccer players.
Method: The study included 42 asymptomatic soccer players (21 women, 21 men; age range 19–31 years). Players from seven teams in the major female professional and amateur male soccer leagues were examined by technetium-99m-methylene diphosphonate (99mTc-MDP) bone scintigraphy during the soccer season. Four hours after intravenous injection of 20 mCi 99mTc-MDP, standard imaging included anterior planar spot images of the legs, lateral images of the knee, and single photon emission computed tomography (SPECT).
Results: Although the players were asymptomatic, increased tracer uptake, indicating stress fracture, was found in 28 (66%). Most of the stress fractures were in the tibia (62%) and femur (5%). In the 42 subjects (84 legs), 35 sites (42%) showed rupture of the posterior horn of the lateral meniscus and bone bruising of the tibial plateau, 16 sites (19%) showed rupture of the anterior horn of the medial meniscus, 11 sites (13%) showed bone bruising of the lateral femoral condyle, eight sites (10%) showed bone bruising of the medial femoral condyle, and there was avulsion injury to the infrapatellar tendon insertion in the anterior tibia in 34 sites (40%). There were 11 anterior cruciate ligament injuries.
Conclusion: Bone SPECT is very accurate, easy to perform, cost effective, may give valuable information before magnetic resonance imaging studies in the detection of meniscal tears, and may be used successfully when magnetic resonance imaging is unavailable.
Objective: The ThinkFirst Canada Smart Hockey program is an educational injury prevention video that teaches the mechanisms, consequences, and prevention of brain and spinal cord injury in ice hockey. This study evaluates knowledge transfer and behavioural outcomes in 11–12 year old hockey players who viewed the video.
Design: Randomized controlled design.
Setting: Greater Toronto Minor Hockey League, Toronto Ontario.
Subjects: Minor, competitive 11–12 year old male ice hockey players and hockey team coaches.
Interventions: The Smart Hockey video was shown to experimental teams at mid-season. An interview was conducted with coaches to understand reasons to accept or refuse the injury prevention video.
Main outcome measures: A test of concussion knowledge was administered before, immediately after, and three months after exposure to the video. The incidence of aggressive penalties was measured before and after viewing the video.
Results: The number of causes and mechanisms of concussion named by players increased from 1.13 to 2.47 and from 0.67 to 1.22 respectively. This effect was maintained at three months. There was no significant change in control teams. There was no significant change in total penalties after video exposure; however, specific body checking related penalties were significantly reduced in the experimental group.
Conclusion: This study showed some improvements in knowledge and behaviours after a single viewing of a video; however, these findings require confirmation with a larger sample to understand the sociobehavioural aspects of sport that determine the effectiveness and acceptance of injury prevention interventions.
To compare the incidence, nature, severity and cause of training injuries sustained on new generation artificial turf and grass by male and female footballers.
The National Collegiate Athletic Association Injury Surveillance System was used for a two‐season (August to December) prospective study involving American college and university football teams (2005 season: men 52 teams, women 64 teams; 2006 season: men 54 teams, women 72 teams). Injury definitions and recording procedures were compliant with the international consensus statement for epidemiological studies of injuries in football. Athletic trainers recorded details of the playing surface and the location, diagnosis, severity and cause of all training injuries. The number of days lost from training and match play was used to define the severity of an injury. Training exposures (player hours) were recorded on a team basis.
The overall incidence of training injuries for men was 3.34 injuries/1000 player hours on artificial turf and 3.01 on grass (incidence ratio 1.11; p = 0.21) and for women it was 2.60 injuries/1000 player hours on artificial turf and 2.79 on grass (incidence ratio 0.93; p = 0.46). For men, the mean severity of injuries that were not season ending injuries was 9.4 days (median 5) on artificial turf and 7.8 days (median 4) on grass and, for women, 10.5 days (median 4) on artificial turf and 10.0 days (median 5) on grass. Joint (non‐bone)/ligament/cartilage and muscle/tendon injuries to the lower limbs were the most common general categories of injury on artificial turf and grass for both male and female players. Most training injuries were acute (men: artificial turf 2.92, grass 2.63, p = 0.24; women: artificial turf 1.94, grass 2.23, p = 0.21) and resulted from player‐to‐player contact (men: artificial turf 1.08, grass 0.85, p = 0.10; women: artificial turf 0.47, grass 0.56; p = 0.45).
There were no major differences between the incidence, severity, nature or cause of training injuries sustained on new generation artificial turf and on grass by either men or women.
acute; gradual onset; contact; non‐contact; risk