Incidence of injury in indoor soccer

A training program to improve neuromuscular and performance indices in female high school soccer players

The purpose of this study was to determine if a sports-specific anterior cruciate ligament injury prevention training program could improve neuromuscular and performance indices in female high school soccer players. We combined components from a published knee ligament intervention program for jump and strength training with other exercises and drills to improve speed, agility, overall strength, and aerobic fitness. We hypothesized that this program would significantly improve neuromuscular and athletic performance indices in high school female soccer players. The supervised 6-week program was done 3 d·wk(-1) for 90-120 minutes per session on the soccer fields and weight room facilities in area high schools. In phase 1, 62 athletes underwent a video drop-jump test, t-test, 2 vertical jump tests, and a 37-m sprint test before and upon completion of the training program. In phase 2, 62 other athletes underwent a multistage fitness test before and after training. There were significant improvements in the mean absolute knee separation distance (p < 0.0001), mean absolute ankle separation distance (p < 0.0001), and mean normalized knee separation distance (p < 0.0001) on the drop-jump, indicating a more neutral lower limb alignment on landing. Significant improvements were found in the t-test (p < 0.0001), estimated maximal aerobic power (p < 0.0001), 37-m sprint test (p = 0.02), and in the 2-step approach vertical jump test (p = 0.04). This is the first study we are aware of that demonstrated the effectiveness of a knee ligament injury prevention training program in improving athletic performance indices in high school female soccer players. Future studies will determine if these findings improve athlete compliance and team participation in knee ligament injury intervention training.

Head and neck injuries in professional soccer

OBJECTIVE

To investigate the rate of and risk factors for head and neck injury in male soccer.

DESIGN

Prospective cohort study.

SETTING

Professional soccer.

PARTICIPANTS

Twenty-six European teams between 2001/2002 and 2009/2010.

ASSESSMENT OF RISK FACTORS

Simple and multiple risk factor analyses were evaluated using Cox regression for player-related variables and logistic regression for match-related variables.

MAIN OUTCOME MEASURES

Injury rate (number of time loss injuries per 1000 hours).

RESULTS

A total of 136 head and neck injuries were recorded (2.2% of all injuries). The head and neck injury rate was 0.17 (0.06 concussions) per 1000 hours. There was a 20-fold higher rate of head and neck injury during match play compared with training (rate ratio [RR], 20.2; 95% confidence interval [CI], 13.3-30.6) and a 78-fold higher rate of concussions (RR, 78.5; 95% CI, 24.4-252.5). Mean layoff for concussion was 10.5 days, but 27% of the concussed players returned to play within 5 days. Defender was the only significant player-related risk factor for head and neck injuries in the multiple analysis (RR, 1.8; 95% CI, 1.0-3.1), whereas no significant variables were identified for concussions.

CONCLUSIONS

Head and neck injuries were relatively uncommon in professional soccer. Defender was the playing position most at risk. More than one-quarter of the concussed players returned to play before what is recommended in the consensus statements by the major sports governing bodies.

Upper extremity injuries in male elite football players

PURPOSE

To investigate the epidemiology of upper extremity injuries in male elite football players and to describe their characteristics, incidence and lay-off times.

METHODS

Between 2001 and 2011, 57 male European elite football teams (2,914 players and 6,215 player seasons) were followed prospectively. Time-loss injuries and exposure to training and matches were recorded on individual basis.

RESULTS

In total, 11,750 injuries were recorded, 355 (3 %) of those affected the upper extremities giving an incidence of 0.23 injuries/1,000 h of football. The incidence in match play was almost 7 times higher than in training (0.83 vs. 0.12 injuries/1,000 h, rate ratio 6.7, 95 % confidence interval 5.5-8.3). As much as 32 % of traumatic match injuries occurred as a result of foul play situations. Goalkeepers had a significantly higher incidence of upper extremity injuries compared to outfield players (0.80 vs. 0.16 injuries/1,000 h, rate ratio 5.0, 95 % confidence interval 4.0-6.2). The average absence due to an upper extremity injury was 23 ± 34 days.

CONCLUSIONS

Upper extremity injuries are uncommon among male elite football players. Goalkeepers, however, are prone to upper extremity injury, with a five times higher incidence compared to outfield players.

LEVEL OF EVIDENCE

II.

Fewer ligament injuries but no preventive effect on muscle injuries and severe injuries: an 11-year follow-up of the UEFA Champions League injury study

BACKGROUND

Limited information is available on the variation in injury rates over multiple seasons of professional football.

AIM

To analyse time-trends in injury characteristics of male professional football players over 11 consecutive seasons.

METHODS

A total of 1743 players comprising 27 teams from 10 countries were followed prospectively between 2001 and 2012. Team medical staff recorded individual player exposure and time loss injuries.

RESULTS

A total of 8029 time loss injuries were recorded. The match unavailability due to injury was 14% and constant over the study period. On average, a player sustained two injuries per season, resulting in approximately 50 injuries per team and season. The ligament injury rate decreased during the study period (R(2)=0.608, b=-0.040, 95% CI -0.065 to -0.016, p=0.005), whereas the rate of muscle injury (R(2)=0.228, b=-0.013, 95% CI -0.032 to 0.005, p=0.138) and severe injury (R(2)=0.141, b=0.015, 95% CI -0.013 to 0.043, p=0.255) did not change over the study period. In addition, no changes in injury rates over the 11-year period were found for either training (R(2)=0.000, b=0.000, 95% CI -0.035 to 0.034, p=0.988) or match play (R(2)=0.282, b=-0.015, 95% CI -0.032 to 0.003, p=0.093).

CONCLUSIONS

The injury rate has decreased for ligament injuries over the last 11 years, but overall training, match injury rates and the rates of muscle injury and severe injury remain high.

The Nordic Football Injury Audit: higher injury rates for professional football clubs with third-generation artificial turf at their home venue

BACKGROUND

Previously, no difference in acute injury rate has been found when playing football on artificial turf (AT) compared with natural grass (NG).

AIM

To compare acute injury rates in professional football played on AT and NG at the individual player level; and to compare, at club level, acute and overuse injury rates between clubs that have AT at their home venue (AT clubs) and clubs that have NG (NG clubs).

METHODS

32 clubs (AT, n=11; NG, n=21) in the male Swedish and Norwegian premier leagues were followed prospectively during the 2010 and 2011 seasons. Injury rate was expressed as the number of time loss injuries/1000 h and compared with rate ratio (RR) and 99% CI.

RESULTS

No statistically significant differences were found in acute injury rates on AT compared with NG during match play (RR 0.98, 99% CI 0.79 to 1.22) or training (RR 1.14, 99% CI 0.86 to 1.50) when analysing at the individual player level. When analysing at the club level, however, AT clubs had a significantly higher acute training injury rate (RR 1.31, 99% CI 1.04 to 1.63) and overuse injury rate (RR 1.38, 99% CI 1.14 to 1.65) compared with NG clubs.

CONCLUSIONS

At the individual player level, no significant differences were found in acute injury rates when playing on AT compared with NG. However, clubs with AT at their home venue had higher rates of acute training injuries and overuse injuries compared with clubs that played home matches on NG.

Lower injury rates for newcomers to professional soccer: a prospective cohort study over 9 consecutive seasons

BACKGROUND

No study has investigated whether newcomers to professional soccer have a different injury rate than established players.

PURPOSE

The primary objective was to investigate whether being a newcomer to professional soccer influences injury rates. The secondary objective was to evaluate whether playing position and player age influence injury rates.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Twenty-six soccer clubs, with 1401 players, were followed prospectively over 9 consecutive seasons between 2001 and 2010. Club medical staff recorded time-loss injuries and soccer exposure on an individual level. Cox regression analyses were used to evaluate associations between time-loss injuries and time in professional soccer, playing position, and age.

RESULTS

In total, 6140 injuries and 797,389 hours of exposure were registered. A decreased general injury rate was observed for newcomers (n = 116) compared with established players (n = 3091) (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.61-0.99). In contrast, newcomers had a higher rate of fractures (rate ratio [RR], 1.77; 95% CI, 1.05-2.97), especially stress-related bone injuries (RR, 2.68; 95% CI, 1.08-6.69). Using goalkeepers as a reference, all outfield playing positions had significantly higher adjusted injury rates: defenders with an HR of 1.91 (95% CI, 1.64-2.24), midfielders with an HR of 1.78 (95% CI, 1.53-2.07), and forwards with an HR of 1.82 (95% CI, 1.55-2.14). Using players aged ≤21 years as a reference, the overall adjusted injury rate increased with age, with a peak injury rate among players aged 29 to 30 years (HR, 1.44; 95% CI, 1.24-1.68).

CONCLUSION

Newcomers to professional soccer had a lower general injury rate than established players but a higher rate of stress-related bone injuries. Being a goalkeeper was associated with lower injury rates than all outfield playing positions. Injury rates increased with age, a pattern that persisted after adjusting for playing position and match exposure.

Acute lateral ankle ligament ruptures in the athlete: the role of surgery

High-level athletes have significantly greater load and demand on their ankle joints than the average population. Therefore, treatment of acute lateral ankle ligament ruptures in the high-demanding athlete is a challenge. This article reviews the treatment of acute lateral ankle ruptures in athletes, with special emphasis on the role of surgical treatment.

Management of acute lateral ankle ligament injury in the athlete

PURPOSE

Inversion injuries involve about 25 % of all injuries of the musculoskeletal system and about 50 % of these injuries are sport-related. This article reviews the acute lateral ankle injuries with special emphasis on a rationale for treatment of these injuries in athletes.

METHODS

A narrative review was performed using Pubmed/Medline, Ovid and Embase using key words: ankle ligaments, injury, lateral ligament, ankle sprain and athlete. Articles related to the topic were included and reviewed.

RESULTS

It is estimated that one inversion injury of the ankle occurs for every 10,000 people each day. Ankle sprains constitute 7-10 % of all admissions to hospital emergency departments. Inversion injuries involve about 25 % of all injuries of the musculoskeletal system, and about 50 % of these injuries are sport-related. The lateral ankle ligament complex consists of three ligaments: the anterior talofibular ligament, the calcaneofibular ligament and the posterior talofibular ligament. The most common trauma mechanism is supination and adduction (inversion) of the plantar-flexed foot.

CONCLUSION

Delayed physical examination provides a more accurate diagnosis. Ultrasound and MRI can be useful in diagnosing associated injury and are routine investigations in professional athletes. Successful treatment of grade II and III acute lateral ankle ligament injuries can be achieved with individualized aggressive, non-operative measures. RICE therapy is the treatment of choice for the first 4-5 days to reduce pain and swelling. Initially, 10-14 days of immobilization in a below the knee cast/brace is beneficial followed by a period in a lace-up brace or functional taping reduces the risk of recurrent injury. Acute repair of the lateral ankle ligaments in grade III injuries in professional athletes may give better results.

The health profile of professional soccer players: future opportunities for injury prevention

Injuries are a major adverse event during a soccer player's career; they require medical and surgical treatment and rehabilitation and thus may interrupt the player's activity, often with severe physical and psychological sequel. Specialists have tried to identify the risk factors for injuries, in an attempt to discover predictors that could be prevented and or eliminated before the injury occurs, but the results are scarce. This article reviews the epidemiology of the frequency and occurrence of injuries in Italian soccer players, reports a list of preventable risk factors that are associated with injuries, and identifies preventable risk factors. We have identified personal factors (age, previous traumatic events, physical and biological characteristics of the player, life style habits such as smoking, alcohol, and diet, changes in physical-athletic aspects of the players, such as increased muscle strength, and use of medications) as possible risk factors for injuries. However, environmental factors such as changes in training techniques, field composition, and shoes structure may also have a major influence. This summary indicates that appropriate preventive measures can be undertaken to prevent injuries in professional soccer players. Professionals who are in close contacts with the players should be informed of the predictors of injuries and should be trained to intervene and plan appropriate preventive measures.

The UEFA injury study: 11-year data concerning 346 MCL injuries and time to return to play

BACKGROUND

Medial collateral ligament (MCL) injury is the most common knee ligament injury in professional football.

AIM

To investigate the rate and circumstances of MCL injuries and development over the past decade.

METHODS

Prospective cohort study, in which 27 professional European teams were followed over 11 seasons (2001/2002 to 2011/2012). Team medical staffs recorded player exposure and time loss injuries. MCL injuries were classified into four severity categories. Injury rate was defined as the number of injuries per 1000 player-hours.

RESULTS

346 MCL injuries occurred during 1 057 201 h (rate 0.33/1000 h). The match injury rate was nine times higher than the training injury rate (1.31 vs 0.14/1000 h, rate ratio 9.3, 95% CI 7.5 to 11.6, p<0.001). There was a significant average annual decrease of approximately 7% (p=0.023). The average lay-off was 23 days, and there was no difference in median lay-off between index injuries and reinjuries (18 vs 13, p=0.20). Almost 70% of all MCL injuries were contact-related, and there was no difference in median lay-off between contact and non-contact injuries (16 vs 16, p=0.74).

CONCLUSIONS

This largest series of MCL injuries in professional football suggests that the time loss from football for MCL injury is 23 days. Also, the MCL injury rate decreased significantly during the 11-year study period.

Incidência e fatores de risco de lesões em jogadores de futsal portugueses

INTRODUÇÃO: A reduzida expressão de estudos publicados sobre a incidência de lesões no Futsal em Portugal justificou a realização deste trabalho. OBJETIVO: Identificar as potenciais causas de lesões nesta modalidade, referência para o desenvolvimento de protocolos específicos de prevenção de lesões. MÉTODOS: A amostra foi constituída por 411 jogadores federados de Futsal em Portugal, masculinos e femininos, de diferentes níveis competitivos. Foram utilizados os dados coletados num questionário com informação retrospectiva. O tratamento estatístico consistiu na análise inferencial entre grupos através do teste de Kruskal-Wallis e do teste para dados não paramétricos de Mann-Whitney (nível de significância de 5%). RESULTADOS: Os resultados confirmaram a entorse da articulação tíbio-társica como a lesão de maior incidência (48,8% do total) no Futsal. As lesões com período de impedimento entre oito e 28 dias tiveram a maior expressão (52,7% do total). Este estudo não revelou diferenças significativas em relação ao gênero ou posição em que os jogadores ocupam na quadra sobre a incidência, o tipo ou a região anatômica das lesões. No entanto, verificou-se significativamente maior incidência de entorses e contraturas em situação de treino e maior incidência de roturas musculares e fraturas em jogo, sendo que essas últimas provocaram um período de impedimento maior para os atletas. Também se verificou significativamente maior incidência de lesões articulares ou ósseas, entorses e fraturas, em resultado do contato com adversários e maior incidência de lesões musculares ou ligamentares sem contato com adversários. Os resultados não evidenciaram diferenças significativas na lateralidade das lesões. CONCLUSÃO: Os resultados realçam a importância de programas específicos de prevenção da entorse da tíbio-társica, especialmente nas crianças e jovens, independentemente da posição que ocupam na quadra, particularmente em situações de contato com adversários.

WITHDRAWN: Immobilisation and functional treatment for acute lateral ankle ligament injuries in adults

BACKGROUND

Acute lateral ankle ligament injuries (ankle sprains) are common problems in acute medical care. The treatment variation observed for the acutely injured lateral ankle ligament complex suggests a lack of evidence-based management strategies for this problem.

OBJECTIVES

The objective of this review was to assess the effectiveness of methods of immobilisation for acute lateral ankle ligament injuries and to compare immobilisation with functional treatment methods.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group specialised register (December 2001); the Cochrane Controlled Trials Register (The Cochrane Library, Issue 4, 2001), MEDLINE (1966-May 2000), EMBASE (1988-May 2000), reference lists of articles, and contacted organisations and researchers in the field.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing either different types of immobilisation or immobilisation versus functional treatments for injuries to the lateral ligament complex of the ankle in adults were included. Trials which investigated the treatment of chronic instability or post-surgical treatment were excluded.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by two authors. Where appropriate, results of comparable studies were pooled using fixed effects models. Individual and pooled statistics were reported as relative risks with 95% confidence intervals for dichotomous outcomes and weighted (WMD) or standardised (SMD) mean differences and 95% confidence intervals for continuous outcome measures. Heterogeneity between trials was tested using a standard chi-squared test.

MAIN RESULTS

Twenty-one trials involving 2184 participants were included. The mean validity score of the included trials increased from 9.1 (SD 3.0) to 10 (SD 2.9) after retrieving further information (maximum 18 points). Statistically significant differences in favour of functional treatment when compared with immobilisation were found for seven outcome measures: more patients returned to sport in the long term (relative risk (RR) 1.86, 95% confidence interval (CI) 1.22 to 2.86); the time taken to return to sport was shorter (WMD 4.88 (days), 95% CI 1.50 to 8.25); more patients had returned to work at short term follow-up (RR 5.75, 95% CI 1.01 to 32.71); the time taken to return to work was shorter (WMD 8.23 days, 95% CI 6.31 to 10.16); fewer patients suffered from persistent swelling at short term follow-up (RR 1.74, 95% CI 1.17 to 2.59); fewer patients suffered from objective instability as tested by stress X-ray (WMD 2.60, 95% CI 1.24 to 3.96); and patients treated functionally were more satisfied with their treatment (RR 1.83, 95% CI 1.09 to 3.07). A separate analysis of trials that scored 50 per cent or more in quality assessment found a similar result for time to return to work only (WMD (days) 12.89, 95% CI 7.10 to 18.67). No significant differences between varying types of immobilisation, immobilisation and physiotherapy or no treatment were found, apart from one trial where patients returned to work sooner after treatment with a soft cast. In all analyses performed, no results were significantly in favour of immobilisation.

AUTHORS' CONCLUSIONS

Functional treatment appears to be the favourable strategy for treating acute ankle sprains when compared with immobilisation. However, these results should be interpreted with caution, as most of the differences are not significant after exclusion of the low quality trials. Many trials were poorly reported and there was variety amongst the functional treatments evaluated.

Measurement of Knee Morphometrics Using MRI: A Comparative Study between ACL-Injured and Non-Injured Knees

PURPOSE

The purpose of this study is to find out the differences of distal femur morphology between the anterior cruciate ligament (ACL)-injured and the non-ACL injured on an magnetic resonance imaging (MRI), and the difference of bone structure by gender.

MATERIALS AND METHODS

MRI Measurements of notch width (NW), bicondylar width (BCW), medial condyle width (MCW), lateral condyle width (LCW), medial-to-lateral condyle ratio (M:L ratio), and notch entrance width (NE) were taken from 120 subjects with ACL injury and the other 106 subjects without ACL injury, by three independent observers, at two different times. The measured values from MRI figures between the ACL-injured and the non-ACL-injured were compared and analyzed, with consideration of the differences by gender. Both intra and inter-observer reliability were calculated.

RESULTS

There were significant differences of NW, BCW, MCW, LCW and NE by gender (p<0.001). While NW and MCW in male group were different (p<0.001), NW, MCW, M:L ratio and NW index (NWI) in female group were significantly different (p<0.001) in the bone morphology between the ACL-injured and non-ACL-injured. The intra- and inter-observer reliability was satisfying.

CONCLUSIONS

If necessary to take an MRI, female patients with small NWI and NW injury should be carefully treated because of possibility of ACL injuries.

A population-based nationwide study of cruciate ligament injury in Sweden, 2001-2009: incidence, treatment, and sex differences

BACKGROUND

A few national cruciate ligament (CL) registers have been initiated with operative surveillance and outcome monitoring. No nationwide study describing CL injury has ever been done.

PURPOSE

To study the incidence and characteristics of patients diagnosed with cruciate ligament injury in Sweden.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Data for all patients with a diagnosed CL injury between 2001 and 2009 were identified from the National Swedish Patient Register. Risk analysis and specific incidences were calculated according to age, sex, geographic region, and surgery.

RESULTS

A total number of 56,659 patients with CL injury were included in the study, and the overall incidence of CL injury in Sweden was 78 per 100,000 persons. Sixty percent of the patients were male. The mean age was 32 years (range, 1-98 years), and 50% of the cohort was younger than 30 years. There was an increased rate of injury among female patients younger than 20 years as compared with male patients in that age group. Among patients with CL injury, 36% underwent reconstructive surgery, with one-third of these performed within 1 year after injury. Among patients who underwent surgery, 59% were male; the mean age was 27 years (range, 5-89 years).

CONCLUSION

This study defines the incidence of CL injury and also demonstrates sex differences in which men were more likely to sustain a CL injury, although female patients were injured at an earlier age. The findings in this study corroborate the results from recent surgical registers.

CLINICAL RELEVANCE

No data have hitherto been published including all patients with CL injury, treated both surgically and nonsurgically. Such baseline epidemiologic data are crucial to be able to validate and judge the generalizability of results from procedure registers and clinical studies.

What is the evidence for rest, ice, compression, and elevation therapy in the treatment of ankle sprains in adults?

CONTEXT

Ankle sprains are common problems in acute medical care. The variation in treatment observed for the acutely injured lateral ankle ligament complex in the first week after the injury suggests a lack of evidence-based management strategies for this problem.

OBJECTIVE

To analyze the effectiveness of applying rest, ice, compression, and elevation (RICE) therapy begun within 72 hours after trauma for patients in the initial period after ankle sprain.

STUDY SELECTION

Eligible studies were published original randomized or quasi-randomized controlled trials concerning at least 1 of the 4 subtreatments of RICE therapy in the treatment of acute ankle sprains in adults.

DATA SOURCES

MEDLINE, Cochrane Clinical Trial Register, CINAHL, and EMBASE. The lists of references of retrieved publications also were checked manually.

DATA EXTRACTION

We extracted relevant data on treatment outcome (pain, swelling, ankle mobility or range of motion, return to sports, return to work, complications, and patient satisfaction) and assessed the quality of included studies. If feasible, the results of comparable studies were pooled using fixed- or random-effects models.

DATA SYNTHESIS

After deduction of the overlaps among the different databases, evaluation of the abstracts, and contact with some authors, 24 potentially eligible trials remained. The full texts of these articles were retrieved and thoroughly assessed as described. This resulted in the inclusion of 11 trials involving 868 patients. The main reason for exclusion was that the authors did not describe a well-defined control group without the intervention of interest.

CONCLUSIONS

Insufficient evidence is available from randomized controlled trials to determine the relative effectiveness of RICE therapy for acute ankle sprains in adults. Treatment decisions must be made on an individual basis, carefully weighing the relative benefits and risks of each option, and must be based on expert opinions and national guidelines.

Exploração de fatores de risco para lesões desportivas em atletas de tênis de mesa

A prática do tênis de mesa requer inúmeras ações dinâmicas que podem conduzir a lesões desportivas, por isso é de importância conhecer fatores inerentes ao traumatismo nos atletas para posterior formulação dos modelos preventivos. Objetivou-se explorar os fatores de risco para lesões desportivas em mesa-tenistas. Para isso, foram entrevistados 111 atletas participantes do Campeonato Paulista de Tênis de Mesa, com média de idade de 22,39±8,88 anos de ambos os gêneros, recrutados ao acaso, classificados em dois níveis competitivos: regional/estadual e nacional/internacional. Utilizou-se o Inquérito de Morbidade Referida adaptado com as características do tênis de mesa com a finalidade de reunir dados pessoais, de treinamento e da lesão desportiva. Foram observadas 0,51 lesões por atleta, e os atletas de nível nacional/internacional apresentaram maiores índices de lesão (52,94%) do que os de nível estadual/regional (48,84%). No gesto específico, notou-se que os membros superiores (93,62%) e o tronco (87,5%) são os locais mais acometidos. Para ambos os níveis, o treinamento foi o momento mais relatado de ocorrência dos agravos. Conclui-se que atletas de nível nacional/internacional possuem maiores índices de lesão e que o gesto específico é a principal causa das lesões, acometendo principalmente os membros superiores e o tronco e ocorrendo com maior frequência durante o treinamento.

Recent advances in the rehabilitation of anterior cruciate ligament injuries

Rehabilitation following anterior cruciate ligament surgery continues to change, with the current emphasis being on immediate weight bearing and range of motion, and progressive muscular strengthening, proprioception, dynamic stability, and neuromuscular control drills. The rehabilitation program should be based on scientific and clinical research and focus on specific drills and exercises designed to return the patient to the desired functional goals. The goal is to return the patient's knee to homeostasis and the patient to his or her sport or activity as safely as possible. Unique rehabilitation techniques and special considerations for the female athlete will also be discussed. The purpose of this article is to provide the reader with a thorough scientific basis for anterior cruciate ligament rehabilitation based on graft selection, patient population, and concomitant injuries.

Measurements of knee morphometrics using MRI and arthroscopy: a comparative study between ACL-injured and non-injured subjects

PURPOSE

The primary purpose of this study was as follows: (1) to compare bony morphology in subjects with and without ACL injury. The secondary purposes were the following: (2) to compare bony morphology between men and women and (3) to determine whether MRI measurements of the notch correlate with intra-operative measurements.

METHODS

MRI measurements of NW, bicondylar width, medial condyle size and lateral condyle size, and medial-to-lateral condyle ratio (M:L) were taken from 45 subjects with ACL injury and 44 subjects without ACL injury, by two independent observers. In addition, notch width measurements were taken arthroscopically in the 45 injured subjects. Knee morphometrics were compared between men and women. Additionally, values of ACL-injured and non-injured subjects were compared for male and female subjects separately. Correlations between notch measurements taken from MRI and measured arthroscopically were determined. Reliability of the MRI measurements was calculated.

RESULTS

Significant differences were found for bicondylar width (P = 0.001), medial condyle width (P = 0.002), and lateral condyle width (P = 0.002) between male and female subjects. When bony morphology was compared between ACL-injured and non-injured subjects, the male subjects showed significant differences for bicondylar width (P = 0.002) and medial condyle width (P = 0.008). For the female subjects, significant differences were found for bicondylar width (P = 0.009) and lateral condyle width (P = 0.002). There was no correlation between notch width measured on the MRI's and NW measured intra-operatively. The intra- and inter-observer reliability of the MRI measurements was satisfactory.

CONCLUSIONS

There were differences in bony morphology between men and women and between subjects with and without ACL injury. The bony morphology that was different between ACL-injured and non-injured subjects varied between male and female subjects.

Regional differences in injury incidence in European professional football

The objective of this study was to investigate regional differences in injury incidence in men's professional football in Europe. A nine-season prospective cohort study was carried out between 2001-2002 and 2009-2010 involving 1357 players in 25 teams from nine countries. Teams were categorized into different regions according to the Köppen-Geiger climate classification system. Teams from the northern parts of Europe (n = 20) had higher incidences of injury overall [rate ratio 1.12, 95% confidence interval (CI) 1.06 to 1.20], training injury (rate ratio 1.16, 95% CI 1.05 to 1.27), and severe injury (rate ratio 1.29, 95% CI 1.10 to 1.52), all statistically significant, compared to teams from more southern parts (n = 5). In contrast, the anterior cruciate ligament injury incidence was lower in the northern European teams with a statistically significant difference (rate ratio 0.43, 95% CI 0.25 to 0.77), especially for noncontact anterior cruciate ligament injury (rate ratio 0.19, 95% CI 0.09 to 0.39). In conclusion, this study suggests that there are regional differences in injury incidence of European professional football. However, further studies are needed to identify the underlying causes.

Hip-abductor fatigue and single-leg landing mechanics in women athletes

CONTEXT

Reduced hip-abductor strength and muscle activation may be associated with altered lower extremity mechanics, which are thought to increase the risk for anterior cruciate ligament injury. However, experimental evidence supporting this relationship is limited.

OBJECTIVE

To examine the changes in single-leg landing mechanics and gluteus medius recruitment that occur after a hip-abductor fatigue protocol.

DESIGN

Descriptive laboratory study.

PATIENTS OR OTHER PARTICIPANTS

Twenty physically active women (age  =  21.0 ± 1.3 years).

INTERVENTION(S)

Participants were tested before (prefatigue) and after (postfatigue) a hip-abductor fatigue protocol consisting of repetitive side-lying hip abduction.

MAIN OUTCOME MEASURE(S)

Outcome measures included sagittal-plane and frontal-plane hip and knee kinematics at initial contact and at 60 milliseconds after initial contact during 5 single-leg landings from a height of 40 cm. Peak hip and knee sagittal-plane and frontal-plane joint moments during this time interval were also analyzed. Measures of gluteus medius activation, including latency, peak amplitude, and integrated signal, were recorded.

RESULTS

A small (<1°) increase in hip-abduction angle at initial contact and a small (<1°) decrease in knee-abduction (valgus) angle at 60 milliseconds after contact were observed in the postfatigue landing condition. No other kinematic changes were noted for the knee or hip at initial contact or at 60 milliseconds after initial contact. Peak external knee-adduction moment decreased 27% and peak hip adduction moment decreased 24% during the postfatigue landing condition. Gluteus medius activation was delayed after the protocol, but no difference in peak or integrated signal was seen during the landing trials.

CONCLUSIONS

Changes observed during single-leg landings after hip-abductor fatigue were not generally considered unfavorable to the integrity of the anterior cruciate ligament. Further work may be justified to study the role of hip-abductor activation in protecting the knee during landing.

Anterior cruciate ligament injury in elite football: a prospective three-cohort study

Anterior cruciate ligament (ACL) injury causes long lay-off time and is often complicated with subsequent new knee injury and osteoarthritis. Female gender is associated with an increased ACL injury risk, but few studies have adjusted for gender-related differences in age although female players are often younger when sustaining their ACL injury. The objective of this three-cohort study was to describe ACL injury characteristics in teams from the Swedish men's and women's first leagues and from several European men's professional first leagues. Over a varying number of seasons from 2001 to 2009, 57 clubs (2,329 players) were followed prospectively and during this period 78 ACL injuries occurred (five partial). Mean age at ACL injury was lower in women compared to men (20.6 ± 2.2 vs. 25.2 ± 4.5 years, P = 0.0002). Using a Cox regression, the female-to-male hazard ratio (HR) was 2.6 (95% CI 1.4-4.6) in all three cohorts studied and 2.6 (95% CI 1.3-5.3) in the Swedish cohorts; adjusted for age, the HR was reduced to 2.4 (95% CI 1.3-4.2) and 2.1 (95% CI 1.0-4.2), respectively. Match play was associated with a higher ACL injury risk with a match-to-training ratio of 20.8 (95% CI 12.4-34.8) and 45 ACL injuries (58%) occurred due to non-contact mechanisms. Hamstrings grafts were used more often in Sweden than in Europe (67 vs. 34%, P = 0.028), and there were no differences in time to return to play after ACL reconstruction between the cohorts or different grafts. In conclusion, this study showed that the ACL injury incidence in female elite footballers was more than doubled compared to their male counterparts, but also that they were significantly younger at ACL injury than males. These findings suggest that future preventive research primarily should address the young female football player.

Current Concepts of Diagnosis and Management of ACL Injuries in Skeletally Immature Athletes

Anterior cruciate ligament (ACL) injuries in skeletally immature athletes are encountered with increasing frequency. The management of such injuries is controversial. Nonsurgical management often results in functional instability and a higher risk of meniscal and chondral injury to the knee. Conventional methods of ACL reconstruction carry the risk of growth disturbance because of iatrogenic damage to the physes around the knee. Multiple cases of growth disturbance have been reported. This article discusses the relevant anatomy, natural history, risk factors, treatment, and prevention of ACL injuries in skeletally immature patients. Surgical treatment is based on physiologic age. For prepubescent patients, we recommend physeal-sparing combined intra-articular/extra-articular reconstruction with autogenous iliotibial band. In adolescent patients with significant growth remaining, we recommend transphyseal ACL reconstruction with hamstrings autograft and fixation away from the physes. In older adolescent patients, we recommend conventional adult ACL reconstruction with autogenous hamstrings or patellar tendon.

Soccer injuries in children

Soccer is the most popular sport in the world, with FIFA recognising more than 265 million amateur players. Despite the fact that soccer is a contact sport, it is perceived to be relatively safe to play, a factor that has contributed to its status as the fastest growing team sport in the USA. Acute and minor injuries predominate in the statistics, with contusions and abrasions being the most commonly recorded. As would be expected, the majority of soccer injuries are to the lower limbs, with serious truncal and spinal trauma being rare. This article examines the type and anatomic location of injuries sustained by children and adolescents who play soccer, and the main mechanisms whereby such injuries occur. The risk factors underpinning injury occurrence are considered, along with injury avoidance tactics.

Side-to-side differences in anterior cruciate ligament volume in healthy control subjects

Examination of anterior cruciate ligament (ACL) anatomy is of great interest both in studying injury mechanisms and surgical reconstruction. However, after a typical acute ACL rupture it is not possible to measure the dimensions of the ACL itself due to concomitant or subsequent degeneration of the remaining ligamentous tissue. The contralateral ACL may be an appropriate surrogate for measuring anatomical dimensions, but it remains unknown whether side-to-side differences preclude using the contralateral as a valid surrogate for the ruptured ACL. This study examined whether the ACL volume is significantly different between the left and right knees of uninjured subjects. ACL volumes were calculated for the left and right sides of 28 individuals using a previously validated MRI-based method. The mean ACL volume was not significantly different (p=0.2331) between the two sides in this population. Side-to-side ACL volume was also well correlated (correlation=0.91, p<0.0001). The results of this study show that the volume of the contralateral ACL is a valid surrogate measure for a missing ACL on the injured side. This non-invasive, in vivo technique for measuring ACL volume may prove useful in future large-scale comprehensive studies of potential risk factors for ACL rupture, in quantifying potential loading effects on ACL size as a prophylactic measure against ACL rupture, and in the use of ACL volume as a screening tool for assessing risk of injury.

Injuries among male and female elite football players

All 12 female football clubs (228 players) and 11 of 14 male clubs (239 players) in the Swedish premier league were followed prospectively during the 2005 season. Individual exposure (playing time), injuries (time loss), and injury severity (days lost due to injury) were recorded by the team medical staffs. Injury incidence was higher for male players during both training (4.7 vs 3.8 injuries/1000 h, P=0.018) and match play (28.1 vs 16.1, P<0.001). However, no difference was found in the incidence of severe injury (absence >4 weeks) (0.7/1000 h in both groups). The thigh, especially the hamstrings, was the overall most commonly injured region in both sexes, while the hip/groin was more commonly injured in male players and the knee in female players. Knee ligament injuries accounted for 31% and 37% of the total time lost from football for male and female players, respectively. In conclusion, male elite players had a higher injury incidence than their female counterparts although no difference was observed in the incidence of moderate to severe injury. We recommend that preventive measures should be focused on hamstring and knee ligament injury in order to reduce the overall injury burden.

Reducing the risk of noncontact anterior cruciate ligament injuries in the female athlete

High school and collegiate female athletes have a significantly increased risk of sustaining a noncontact anterior cruciate ligament injury compared with male athletes participating in the same sport. This review summarizes the current knowledge of the risk factors hypothesized to influence this problem, and the neuromuscular training programs designed to correct certain biomechanical problems noted in female athletes. The risk factors include a genetic predisposition for sustaining a knee ligament injury, environmental factors, anatomical indices, hormonal influences, and neuromuscular factors. The greatest amount of research in this area has studied differences between female and male athletes in movement patterns during athletic tasks; muscle strength, activation, and recruitment patterns; and knee joint stiffness under controlled, preplanned, and reactive conditions in the laboratory. Neuromuscular retraining programs have been developed in an attempt to reduce these differences. The successful programs teach athletes to control the upper body, trunk, and lower body position; lower the center of gravity by increasing hip and knee flexion during activities; and develop muscular strength and techniques to land with decreased ground reaction forces. In addition, athletes are taught to preposition the body and lower extremity prior to initial ground contact to obtain the position of greatest knee joint stability and stiffness. Two published programs have significantly reduced the incidence of noncontact anterior cruciate ligament injuries in female athletes participating in basketball, soccer, and volleyball. Other programs were ineffective, had a poor study design, or had an insufficient number of participants, which precluded a true reduction in the risk of this injury. In order to determine which risk factors for noncontact anterior cruciate ligament ruptures are significant, future investigations should include larger cohorts of athletes in multiple sports, analyze factors from all of the major risk categories, and follow athletes for at least one full athletic season. Future risk assessment studies should incorporate reactive tasks under more realistic sports conditions.

Influence of age, sex, technique, and exercise program on movement patterns after an anterior cruciate ligament injury prevention program in youth soccer players

BACKGROUND

Anterior cruciate ligament (ACL) injury prevention programs show promising results with changing movement; however, little information exists regarding whether a program designed for an individual's movements may be effective or how baseline movements may affect outcomes.

HYPOTHESIS

A program designed to change specific movements would be more effective than a "one-size-fits-all" program. Greatest improvement would be observed among individuals with the most baseline error. Subjects of different ages and sexes respond similarly.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

One hundred seventy-three youth soccer players from 27 teams were randomly assigned to a generalized or stratified program. Subjects were videotaped during jump-landing trials before and after the program and were assessed using the Landing Error Scoring System (LESS), which is a valid clinical movement analysis tool. A high LESS score indicates more errors. Generalized players performed the same exercises, while the stratified players performed exercises to correct their initial movement errors. Change scores were compared between groups of varying baseline errors, ages, sexes, and programs.

RESULTS

Subjects with the highest baseline LESS score improved the most (95% CI, -3.4 to -2.0). High school subjects (95% CI, -1.7 to -0.98) improved their technique more than pre-high school subjects (95% CI, -1.0 to -0.4). There was no difference between the programs or sexes.

CONCLUSIONS

Players with the greatest amount of movement errors experienced the most improvement. A program's effectiveness may be enhanced if this population is targeted.

The anatomy in relation to injury of the lateral collateral ligaments of the ankle: a current concepts review

Injuries to the lateral ligament complex of the ankle are common problems in acute care practice. We believe that a well-developed knowledge of the anatomy provides a foundation for understanding the basic mechanism of injury, diagnosis, and treatment, especially surgical treatment, of lateral collateral ankle ligament injury. To address this issue we performed this review with regard to the anatomy of the lateral collateral ankle ligaments.

A randomized controlled trial to prevent noncontact anterior cruciate ligament injury in female collegiate soccer players

BACKGROUND

Neuromuscular and proprioceptive training programs can decrease noncontact anterior cruciate ligament injuries; however, they may be difficult to implement within an entire team or the community at large.

HYPOTHESIS

A simple on-field alternative warm-up program can reduce noncontact ACL injuries.

STUDY DESIGN

Randomized controlled trial (clustered); Level of evidence, 1.

METHODS

Participating National Collegiate Athletic Association Division I women's soccer teams were assigned randomly to intervention or control groups. Intervention teams were asked to perform the program 3 times per week during the fall 2002 season. All teams reported athletes' participation in games and practices and any knee injuries. Injury rates were calculated based on athlete exposures, expressed as rate per 1000 athlete exposures. A z statistic was used for rate ratio comparisons.

RESULTS

Sixty-one teams with 1435 athletes completed the study (852 control athletes; 583 intervention). The overall anterior cruciate ligament injury rate among intervention athletes was 1.7 times less than in control athletes (0.199 vs 0.340; P = .198; 41% decrease). Noncontact anterior cruciate ligament injury rate among intervention athletes was 3.3 times less than in control athletes (0.057 vs 0.189; P = .066; 70% decrease). No anterior cruciate ligament injuries occurred among intervention athletes during practice versus 6 among control athletes (P = .014). Game-related noncontact anterior cruciate ligament injury rates in intervention athletes were reduced by more than half (0.233 vs 0.564; P = .218). Intervention athletes with a history of anterior cruciate ligament injury were significantly less likely to suffer another anterior cruciate ligament injury compared with control athletes with a similar history (P = .046 for noncontact injuries).

CONCLUSION

This program, which focuses on neuromuscular control, appears to reduce the risk of anterior cruciate ligament injuries in collegiate female soccer players, especially those with a history of anterior cruciate ligament injury.

Influence of age, gender, and injury mechanism on the development of dynamic knee stability after acute ACL rupture

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To determine whether the distribution of those with and without dynamic knee stability after anterior cruciate ligament (ACL) rupture differs by age, gender, and contact versus non-contact injury mechanisms.

BACKGROUND

There is a differential return to preinjury activities after ACL rupture. It is unknown if there are specific patient groups who are more or less likely to experience good dynamic knee stability after ACL rupture.

METHODS AND MEASURES

The study sample consisted of 345 consecutive, highly active patients with complete, isolated ACL insufficiency. Based on the results of a screening examination, patients were categorized as having either good (potential coper) or poor (noncoper) dynamic knee stability. Descriptive and chi-square statistics were calculated to describe patient characteristics and identify the proportion of potential copers and noncopers based on age, gender, and injury mechanism.

RESULTS

The groups with the greatest proportion of noncopers were women (P=0.002), mid-aged adults (35-44 years old) (P<0.001), and individuals who sustained a noncontact ACL injury (P=0.011).

CONCLUSIONS

Women who sustain an ACL rupture, and those who sustain an ACL rupture via a noncontact mechanism frequently experience dynamic knee instability. A profile of demographic characteristics of those most likely to experience knee instability after ACL rupture may facilitate improved patient outcomes.

Personality Traits Relate to Heading Frequency in Male Soccer Players

Concussions in soccer are often coincident with the act of heading the ball, and some researchers have reported that soccer heading is associated with neurocoginitive decrements. This study aimed to understand (a) the personality factors that may predict frequent soccer heading, and (b) how knowledge of players’ personality traits might help sport counselors persuade neurologically at-risk players to moderate their heading behavior. Sixty elite male soccer players (ages 16-34) completed structured self-report interviews, the NEO-FFI personality inventory, and the Arnett Inventory of Sensation Seeking. Players who headed most had significantly higher extraversion scores than comparison athletes and soccer players who headed less. Physical height was the best predictor of heading frequency but was not correlated with extraversion, which was also a significant predictor. Players with the typical profile of the high heading group may be more resistant to suggestion that they alter their style of play for safety reasons.

A meta-analysis of the incidence of anterior cruciate ligament tears as a function of gender, sport, and a knee injury-reduction regimen

PURPOSE

The literature has shown that anterior cruciate ligament (ACL) tear rates vary by gender, by sport, and in response to injury-reduction training programs. However, there is no consensus as to the magnitudes of these tear rates or their variations as a function of these variables. For example, the female-male ACL tear ratio has been reported to be as high as 9:1. Our purpose was to apply meta-analysis to the entire applicable literature to generate accurate estimates of the true incidences of ACL tear as a function of gender, sport, and injury-reduction training.

METHODS

A PubMed literature search was done to identify all studies dealing with ACL tear incidence. Bibliographic cross-referencing was done to identify additional articles. Meta-analytic principles were applied to generate ACL incidences as a function of gender, sport, and prior injury-reduction training.

RESULTS

Female-male ACL tear incidences ratios were as follows: basketball, 3.5; soccer, 2.67; lacrosse, 1.18; and Alpine skiing, 1.0. The collegiate soccer tear rate was 0.32 for female subjects and 0.12 for male subjects. For basketball, the rates were 0.29 and 0.08, respectively. The rate for recreational Alpine skiers was 0.63, and that for experts was 0.03, with no gender variance. The two volleyball studies had no ACL tears. Training reduced the ACL tear incidence in soccer by 0.24 but did not reduce it at all in basketball.

CONCLUSIONS

Female subjects had a roughly 3 times greater incidence of ACL tears in soccer and basketball versus male subjects. Injury-reduction programs were effective for soccer but not basketball. Recreational Alpine skiers had the highest incidences of ACL tear, whereas expert Alpine skiers had the lowest incidences. Volleyball may in fact be a low-risk sport rather than a high-risk sport. Alpine skiers and lacrosse players had no gender difference for ACL tear rate. Year-round female athletes who play soccer and basketball have an ACL tear rate of approximately 5%.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Injury risk from popular childhood physical activities: results from an Australian primary school cohort

BACKGROUND

Children engage in various physical activities that pose different injury risks. However, the lack of adequate data on exposure has meant that these risks have not been quantified or compared in young children aged 5-12 years.

OBJECTIVES

To measure exposure to popular activities among Australian primary school children and to quantify the associated injury risks.

METHOD

The Childhood Injury Prevention Study prospectively followed up a cohort of randomly selected Australian primary and preschool children aged 5-12 years. Time (min) engaged in various physical activities was measured using a parent-completed 7-day diary. All injuries over 12 months were reported to the study. All data on exposure and injuries were coded using the International classification of external causes of injury. Injury rates per 1000 h of exposure were calculated for the most popular activities.

RESULTS

Complete diaries and data on injuries were available for 744 children. Over 12 months, 314 injuries relating to physical activity outside of school were reported. The highest injury risks per exposure time occurred for tackle-style football (2.18/1000 h), wheeled activities (1.72/1000 h) and tennis (1.19/1000 h). Overall, boys were injured more often than girls; however, the differences were non-significant or reversed for some activities including soccer, trampolining and team ball sports.

CONCLUSION

Although the overall injury rate was low in this prospective cohort, the safety of some popular childhood activities can be improved so that the benefits may be enjoyed with fewer negative consequences.

Mechanisms of non-contact ACL injuries

In soccer one of the most common knee injuries is the anterior cruciate ligament (ACL) tear, which usually occurs through non-contact mechanisms. Female soccer players are at higher risk of sustaining non-contact ACL injuries than male soccer players. A good understanding of ACL loading mechanisms is the basis for a good understanding of the mechanisms of non-contact ACL injuries, which in turn is essential for identifying risk factors and developing prevention strategies. Current literature demonstrates that sagittal plane biomechanical factors, such as small knee flexion angle, great posterior ground reaction force and great quadriceps muscle force, are the major ACL loading mechanisms. A great posterior ground reaction force may be associated with a great quadriceps muscle force, which would cause great anterior draw force at the knee. A small knee flexion is associated with a large patella tendon-tibia shaft angle and ACL elevation angle, which would result in great ACL loading. Current literature also demonstrates that the ACL is not the major structure of bearing knee valgus-varus moment and internal-external rotation loadings. Knee valgus-varus moment and internal-external rotation moment alone are not likely to result in isolated ACL injuries without injuring other knee structures.

Quantifying the risk of sports injury: a systematic review of activity-specific rates for children under 16 years of age

Injuries caused by sports and other forms of physical activity in young children constitute a significant public health burden. It is important to quantify this risk to ensure that the benefits of sport participation are not outweighed by the potential harms. This review summarises the literature reporting exposure-based injury rates for various forms of physical activity in children aged 15 years and younger. Forty eight studies were found, of which 27 reported injury rates per hourly based exposure measured and 21 reported injury rates according to some other measure. Fourteen different sports and activities were covered, mostly team ball sports, with soccer being the most widely studied. Injury definition and the method of ascertaining and measuring injuries differed between studies, which created a large variation in reported injury rates that did not necessarily represent actual differences in injury risk between activities. The highest hourly based injury rates were reported for ice hockey, and the lowest were for soccer, although the range of injury rates for both of these activities was wide. Very few studies have investigated sports-related injuries in children younger than 8 years or in unorganised sports situations.

Lower reinjury rate with a coach-controlled rehabilitation program in amateur male soccer: a randomized controlled trial

BACKGROUND

Soccer injuries are common, and athletes returning to play after injury are especially at risk. Few studies have investigated how to prevent reinjury.

HYPOTHESIS

The rate of reinjury is reduced using a coach-controlled rehabilitation program.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Twenty-four male amateur soccer teams were randomized into an intervention (n = 282) and control group (n = 300). The intervention was implemented by team coaches and consisted of information about risk factors for reinjury, rehabilitation principles, and a 10-step progressive rehabilitation program including return to play criteria. During the 2003 season, coaches reported individual exposure and all time loss injuries were evaluated by a doctor and a physiotherapist. Four teams (n = 100) withdrew from the study after randomization, leaving 10 teams with 241 players for analysis in both groups.

RESULTS

There were 90 injured players (132 injuries) in the intervention group, and 10 of these (11%) suffered 14 reinjuries during the season. In the control group, 23 of 79 injured players (29%) had 40 recurrences (134 injuries). A Cox regression analysis showed a 66% reinjury risk reduction in the intervention group for all injury locations (hazard ratio [HR] 0.34, 95% confidence interval [CI] 0.16-0.72, P = .0047) and 75% for lower limb injuries (HR 0.25, 95% CI 0.11-0.57, P < .001). The preventive effect was greatest within the first week of return to play. Injured players in the intervention group complied with the intervention for 90 of 132 injuries (68%).

CONCLUSION

The reinjury rate in amateur male soccer players was reduced after a controlled rehabilitation program implemented by coaches.

A comparison of cleat types during two football-specific tasks on FieldTurf

OBJECTIVE

To examine the effect of different cleat plate configurations on plantar pressure during two tasks.

DESIGN

Thirty-six athletes ran an agility course 5 times while wearing 4 different types of Nike Vitoria cleats: (1) bladed, (2) elliptical firm ground, (3) hard ground and (4) turf. Plantar pressure data were recorded during a side cut and a cross cut using Pedar-X insoles.

SETTING

Controlled laboratory study

PARTICIPANTS

No history of lower extremity injury in the past 6 months, no previous foot or ankle surgery, not currently wearing foot orthotics and play a cleated sport at least twice a week.

MAIN OUTCOME MEASUREMENTS

Total foot contact time, contact area, maximum force, peak pressure and the force-time integral (FTI) in the medial, middle and lateral regions of the forefoot were collected. A 1x4 ANOVA (alpha = 0.05) was performed on each dependent variable. A Bonferroni adjustment was conducted (alpha = 0.008).

RESULTS

In the cross cut task, statistical differences between cleats were observed in three variables: total foot peak pressure, lateral forefoot FTI, and lateral forefoot normalised maximum force. In the side cut task, statistical differences between cleats were observed in 4 variables: total foot peak pressure, the medial and middle forefoot FTI, and the medial and middle forefoot normalised maximum force.

CONCLUSIONS

Significant differences in forefoot loading patterns existed between cleat types. Based on the results of this study, it might be beneficial to increase the forefoot cushioning in cleats in an attempt to decrease loading in these regions of the foot.

Knee and hip loading patterns at different phases in the menstrual cycle: implications for the gender difference in anterior cruciate ligament injury rates

BACKGROUND

Menstrual cycle phase has been correlated with risk of noncontact anterior cruciate ligament injury in women. The mechanism by which hormonal cycling may affect injury rate is unknown.

HYPOTHESES

Jumping and landing activities performed during different phases of the menstrual cycle lead to differences in foot strike knee flexion, as well as peak knee and hip loads, in women not taking an oral contraceptive but not in women taking an oral contraceptive. Women will experience greater normalized joint loads than men during these activities.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty-five women (13 using oral contraceptives) and 12 men performed repeated trials of a horizontal jump, vertical jump, and drop from a 30-cm box on the left leg. Lower limb kinematics (foot strike knee flexion) and peak externally applied moments were calculated (hip adduction moment, hip internal rotation moment, knee flexion moment, knee abduction moment). Men were tested once. Women were tested twice for each phase of the menstrual cycle (follicular, luteal, ovulatory), as determined from serum analysis. An analysis of variance was used to examine differences between phases of the menstrual cycle and between groups (alpha = .05).

RESULTS

No significant differences in moments or knee angle were observed between phases in either female group or between the 2 female groups or between either female group and the male controls.

CONCLUSIONS

Variations of the menstrual cycle and the use of an oral contraceptive do not affect knee or hip joint loading during jumping and landing tasks.

CLINICAL RELEVANCE

Because knee and hip joint loading is unaffected by cyclic variations in hormone levels, the observed difference in injury rates is more likely attributable to persistent differences in strength, neuromuscular coordination, or ligament properties.