Injuries in Spanish female soccer players

'Benched' the effect of the COVID-19 lockdown on injury incidence in sub-elite football in Australia: a retrospective population study using injury insurance records

OBJECTIVES

The primary aim of this study was to compare injury rates pre- and post-COVID-19 lockdown in sub-elite football (soccer) players by analysing the full season and the first month of each season between 2018 and 2020. Secondary aims were to describe the incidence, location and type of injuries and to compare injuries by age group and sex.

DESIGN

Descriptive epidemiological study.

METHODS

A de-identified insurance database was retrospectively coded using the Orchard Sports Injury Classification System. Injury incidence per 1000 hours as well as incidence rate ratios (IRR) with confidence intervals were calculated.

RESULTS

No significant difference was found in the overall incidence rate in 2020 compared with the 2018 and 2019 seasons (IRR, 1.04 [95% CI, 0.96-1.13]; p = 0.294). However, overall injuries increased by 26% (IRR: 1.26 [95% CI 1.07-1.47]; p < 0.005) and joint sprains increased by 45% (IRR: 1.45 [95% CI 1.14-1.84]; p < 0.005) in the first month of 2020 compared with 2018-2019. Between 2018 and 2020, there were 4149 injury insurance claims, with anterior cruciate ligament (ACL) ruptures accounting for 19% of all injuries. When comparing sex, female players had significantly more ankle sprains whilst male players suffered more dental injuries.

CONCLUSIONS

This study adds to a growing body of evidence investigating injury rates post-COVID-19 lockdowns in sport. Sub-elite players appear to be at higher risk of joint injuries within the first month of training following a period of lockdown. Overall, stakeholders involved in sub-elite football should prioritise knee and ankle joint injury prevention.

Prediction of ACL-tear by lower limbs muscle strength and flexibility: a prospective cohort study in 95 female soccer players

The aims of the study were to build models using logistic regression analysis of flexibility and strength tests to prospectively predict risk factors for anterior cruciate ligament tear (ACL-tear) in female soccer (FS) players, and to determine training cut-off for risk factors of the predictive model built. A prospective cohort study of 95 female players (aged 14-33 years) was conducted. Age, anthropometric data, soccer history, lower limb range of motion (ROM) and hip maximal isometric strength (MIS) were measured. At the prospective follow-up after 12 months, 7.4% of the players had developed an ACL-tear. The model showed a significant relationship (χ2(93) = 30.531, p < 0.001) between the ACL-tear and the predictor variables (leg length, HAD-NH [hip adduction] MIS, asymmetric ROM [ankle dorsiflexion with knee extended (AD-KE) and with knee flexed (AD-KF), and HE (hip extension)], hip ROM [HIR (internal rotation) and HAB (abduction)]). The Akaike Information Criteria (AIC) and Bayesian Information Criteria (BIC) for model fit were 30.24 and 51.79, respectively. The value R2 showed good model fit, 76.5% for Nagelkerke´s R2, 71.4% for McFadden´s R2 and 67.5% for Tjur´s R2. For the screening test, cut-off for leg length of ≥0.40 m, for HIR ROM of ≤44º and for asymmetry of HE ROM of ≥5° were set, which have an acceptable (AUC ≥ 0.755) discriminatory ability for the development of ACL-tear.

Higher age and present injury at the start of the season are risk factors for in-season injury in amateur male and female football players-a prospective cohort study

PURPOSE

To describe the injury prevalence, injury pattern, and potential baseline risk factors for injuries in male and female adolescent and adult amateur football players.

METHODS

This prospective study followed adolescent and adult amateur football players over one season March-October 2020. The study was completed by 462 players (130 men, age 20.0 ± 5.7, 14-46 years) who answered a baseline survey and a weekly web survey during the season. A total of 1456 weekly surveys were registered from males and 5041 from females. Injuries were recorded with the Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSTRC-O2). Potential baseline risk factors (age, performance of strength/conditioning training, participation in other sports, perceived importance of sporting success, self-rated training and match load, perceived balance between training/match load and recovery, previous/present injury at start of season, and injury beliefs) and their association with injury were analysed with Poisson regressions within each sex.

RESULTS

Males reported 95 injuries (262 injury weeks, weekly prevalence 18.0% (95% CI 16.1-20.1)) and females 350 injuries (1206 injury weeks, weekly prevalence 23.9% (95% CI 22.8-25.1)). Gradual-onset injuries accounted for 57% of the injuries in males and 66% in females. For males, substantial injuries were most common in the hip/groin (weekly prevalence 3.8%), ankle (2.1%), posterior thigh (2.0%), and knee (2.0%); and for females, in the knee (4.3%), ankle (2.5%), and lower leg/Achilles tendon (2.0%). Significant risk factors for injury were higher age (rate ratio males 1.05 per year increase (95% CI 1.02-1.08), females 1.03 (95% CI 1.01-1.05)), and present injury at baseline (males 1.92 (95% CI 1.27-2.89), females 1.58 (95% CI 1.19-2.09)).

CONCLUSION

At any given week, almost one in five male and one in four female amateur football players reported new or ongoing injuries. Hip/groin injuries were more frequent in males, while female players had a higher prevalence of knee injuries. Older players and those with an existing injury at the start of the season were more prone to new injury during the season. Rehabilitation of pre-season injury and complaints are key to reduce the injury burden in amateur football.

LEVEL OF EVIDENCE

Level II. Trial registration number NCT04272047, Clinical trials.

Health problems occurring in national-level female soccer players are different between leagues and throughout the season: a 6-month prospective cohort study

Objectives

This study investigated the prevalence and severity of health problems in national-level female soccer players with respect to league and seasonality.

Methods

In a prospective cohort study, 46 female soccer players aged 22.8±3.9 years playing in the three highest leagues in Switzerland were surveyed biweekly using the Oslo Sports Trauma Research Centre health problem (OSTRC-H) questionnaire. All definitions and measures followed the OSTRC-H-specific recommendations. The 6-month observation period included parts of the off-season and one half of the match season.

Results

The average 2-weekly health problem prevalence was 37.3% (illnesses: 8.8%; sudden onset injuries-both acute and repetitive mechanisms: 19.7%; repetitive gradual onset injuries: 12.4%) and 25.1% for substantial problems as defined in the OSTRC-H context (7.3%; 12.0% and 7.3%, respectively). The absolute injury rates amounted to 148 injuries per 100 players per half season, of which 96 injuries per 100 players per half season were substantial. Female players in the 2nd and 3rd highest national leagues showed more gradual onset injuries (p<0.001) and fewer illnesses than those in the top league (p<0.05). At the same time, there were no league-specific differences in sudden onset injuries. Such injuries had a higher cumulative severity score than gradual onset injuries. Among sudden onset injuries, the ankle was the most affected body part, while the thigh was affected by for gradual onset injuries. The average 2-weekly health problem prevalence values steadily increased during the match season.

Conclusion

Among national-level female soccer players, the risk of health problems is relatively high and differs between leagues and across seasons.

The Effect on Flexibility and a Variety of Performance Tests of the Addition of 4 Weeks of Soleus Stretching to a Regular Dynamic Stretching Routine in Amateur Female Soccer Players

The purpose of this study was to investigate the effects of 4 weeks of soleus stretching on ankle flexibility and dynamic balance, as well as selected monitoring and performance tests in soccer. Forty-five healthy female soccer players were randomly divided into a regular stretching group, a regular stretching group with soleus stretching, and a control group. Dynamic stretching protocols were performed for 4 weeks during three sessions per week as part of routine exercises. The regular group stretched three muscle groups (i.e., gastrocnemius, quadriceps, and hamstrings), while the regular + soleus group also stretched the soleus muscle. Before and after the stretching intervention, the ankle range of motion test, Y-balance test, drop jump test, dynamic knee valgus test, and Illinois Agility Running Test were performed. Ankle ROM, Y-balance, and DJ significantly improved in both intervention groups compared to controls. Only the regular + soleus group showed improvement in the Illinois Agility Running Test. Additionally, athletes performing the additional soleus stretching had greater improvements in ankle ROM and DJ but not in DKV or Y-balance. The results showed that adding soleus stretching into regular protocols can provide benefits for female soccer players in terms of performance parameters.

The Effects of Fixture Congestion on Injury in Professional Male Soccer: A Systematic Review

BACKGROUND

Professional soccer teams are often required to compete with ≤ 4 days recovery between matches. Since congested schedules reduce recovery time between matches, players are possibly at an increased injury risk. To date, there are no published systematic reviews on the impact of match congestion on injuries during professional male soccer.

OBJECTIVE

The aim of this systematic review was to assess the effects of fixture congestion on injuries during professional soccer.

METHODS

Following pre-registration on the Open Science Framework ( https://osf.io/86m25/ ) and conforming with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, systematic searches of four electronic databases (PubMed, Scopus, SPORTDiscus, and Web of Science) were conducted by independent researchers from inception until February 2022. Articles were included if they were original articles written in English and contained relevant time-loss injury data (injury that results in unavailability for training and/or match-play) for male professional soccer players regarding periods of fixture congestion (a minimum of two matches with ≤ 4 days recovery).

RESULTS

A total of eight articles were included in the review. Five studies identified that congested fixture schedules expose players to increased match injury incidence, although layoff duration was typically lower during congested periods. Two studies identified that training and overall injury incidence were higher during congested periods, with another study identifying a lower training injury incidence during congested periods.

CONCLUSION

Injury risk is, overall, increased during fixture-congested periods; however, the layoff duration is typically shorter. The current findings have implications for practitioners regarding the management, periodisation, monitoring, and design of training and competition schedules.

Injury, illness, and medication use surveillance during the 2020 COSAFA Women's championship: a prospective cohort study of football players from Southern Africa

BACKGROUND

Systematic analyses of injuries, illnesses or medication use and their risk factors among female African athletes are scarce, which has implications for management of these athletes.

AIM

This prospective cohort study analysed the incidence and characteristics of injuries, illnesses and medication use during the 2020 COSAFA Women's Championship.

METHODS

The medical personnel of all participating teams reported all new injuries, illnesses and medication used by players daily.

RESULTS

Sixty-three injuries were reported: 45 match and 18 training injuries; 45.5 (95% CI: 32.2 to 58.8) injuries/1000 match-hours and 21.7 (95% CI: 11.7 to 31.7) injuries/1000 training-hours, respectively. Most (n = 55, 87%) were caused by contact with another player and involved the lower extremity (n = 43; 68%). Fifty-eight illnesses were reported: 44.4 (95% CI: 33.0 to 58.8) illnesses/1000 player-days, mostly diarrhoea (n = 25; 43.1%) and dysmenorrhoea (n = 18; 31%). No cases of COVID-19 were reported. In total, 175 medications were prescribed: 168.8 (95% CI: 143.8 to 193.8) medications/1000 player-days. Non-steroidal anti-inflammatory drugs (NSAIDs) (n = 60; 34.3%) and analgesics (n = 33; 18.9%) were the most commonly prescribed drugs.

CONCLUSION

Incidences of injury and illnesses were high but time loss was low, likely due to high NSAIDs use. Further studies should be conducted in order to inform appropriate prevention or management protocols in this population.

Injury incidence and risk factors in youth soccer players: a systematic literature review. Part I: epidemiological analysis

The analysis of the epidemiological data and the risk factors underlying injuries is crucial to promote prevention strategies in young soccer players. The objective of the present study was to perform a systematic literature review on the epidemiological data, described in the first part, and injury risk factors, presented in the second part. After electronic database searching, articles in line with the inclusion criteria were selected for the systematic review. Epidemiological data were extracted and discussed in this first part of the review. Data were grouped as follows: injury incidence, injury severity, and re-injury, injury types, injury mechanisms, and anatomical location. The principal findings of this first part of the review are as follows: (1) injury incidence is higher in older players and during matches than during training; (2) sex and maturity status may increase risk of injury; (3) male soccer players are more prone to muscle strains and ligament sprains while female players suffer more ligament sprains; (4) most injuries are located in the ankle and thigh in young male soccer players, and in the ankle and knee in female players; (5) severe injuries are less frequent but the incidence increases in older players. Re-injuries represent only a small percentage. Although soccer is considered a safe sport, many injuries are recorded in young soccer players every year. Injury predisposition changes in relation to age, sex, and biological age. Coaches and physical trainers should be aware of individual differences in order to promote prevention strategies and personalised training.

Player Sex and Playing Surface Are Individual Predictors of Injuries in Professional Soccer Players

Background: The factors contributing to soccer injuries and their influence on the occurrence of injury are controversial and inconclusive. This study aimed to determine the association between player characteristics and playing factors with injuries in professional soccer players. Methods: One hundred and fifty-two professional soccer players completed a self-administered questionnaire that asked about demographic information and injury profile, the type of playing surface on which they sustained their injury, medical treatment, and the time lost due to soccer injury at the end of the soccer season. Results: The injury rate was 44.74% (n = 68; males: 61.50% (n = 56), females: 19.70% (n = 12)). Players’ age (OR: 1.15, 95%CI: 1.05−1.25, p < 0.002) and BMI (OR: 1.21, 95%CI: 1.06−1.38, p < 0.003) were significantly associated with soccer injuries. After adjusting for age and BMI, players’ sex (OR: 5.39, 95%CI: 2.11−13.75, p < 0.001), previous soccer injury (OR: 3.308, 95%CI: 2.307−29.920, p < 0.001), and playing surfaces (OR: 11.07, 95%CI: 4.53−27.03, p < 0.001) were the significant predictors of soccer injuries. Conclusion: Players’ age, BMI, sex, previous soccer injury, and playing surface were associated with injuries among professional soccer players. Old male athletes with high BMI, previous soccer injuries, and playing on natural grass were more likely to sustain soccer injuries than young female players with low BMI who had no previous injuries and played on synthetic surfaces.

Epidemiology of soccer injuries in Korea women national team for 5 years

The purpose of this study was to analyze the characteristics of injuries in female national soccer players. The injuries data were recorded by Korea Football Association medical staff using the Daily Medical Report provided by the Asian Football Confederation during a total 21 training camps and friendly and official matches from January 2014 to December 2018. A total of 483 players in the national team training camps and matches participated in the study, of which 377 players experienced more than one injury. Sports injuries accounted for 89% of the total 1,019 injuries; general diseases accounted for the remaining 11%. The number of injuries per 1,000 exposure hours was higher in matches than in training sessions. Most injuries that occurred during training and matches involved the lower extremities (79%). The most common injury diagnosed during training and matches was muscle rigidity (45%), followed by contusions/hematomas/bruises (22%) and sprain (15%). The largest proportions of injuries in terms of absence from soccer play were minimal injury (67%), followed by mild (29%), moderate (3.5%), and severe (1%). As conclusion, the characteristics of injuries during training sessions and matches were different. Rehabilitation and injury prevention programs need to developed for female soccer players to improve the players’ performance.

Physiological Characteristics of Female Soccer Players and Health and Performance Considerations: A Narrative Review

Female soccer has seen a substantial rise in participation, as well as increased financial support from governing bodies over the last decade. Thus, there is an onus on researchers and medical departments to develop a better understanding of the physical characteristics and demands, and the health and performance needs of female soccer players. In this review, we discuss the current research, as well as the knowledge gaps, of six major topics: physical demands, talent identification, body composition, injury risk and prevention, health and nutrition. Data on female talent identification are scarce, and future studies need to elucidate the influence of relative age and maturation selection across age groups. Regarding the physical demands, more research is needed on the pattern of high-intensity sprinting during matches and the contribution of soccer-specific movements. Injuries are not uncommon in female soccer players, but targeting intrinsically modifiable factors with injury prevention programmes can reduce injury rates. The anthropometric and physical characteristics of female players are heterogeneous and setting specific targets should be discouraged in youth and sub-elite players. Menstrual cycle phase may influence performance and injury risk; however, there are few studies in soccer players. Nutrition plays a critical role in health and performance and ensuring adequate energy intake remains a priority. Despite recent progress, there is considerably less research in female than male soccer players. Many gaps in our understanding of how best to develop and manage the health and performance of female soccer players remain.

Injury analysis of a professional female soccer team in first division Italian season

BACKGROUND

Soccer, the most popular sport worldwide, has seen an exponential increase in women's participation at the elite level in the last few years. The main purpose of the current epidemiological study was to analyze the injury incidence, characteristics, and burden among elite female soccer players during a regular season.

METHODS

We recorded all injuries that occurred throughout the 2018-2019 competitive soccer season (August-April). The studied group consisted of 22 elite players, who were militant in the first national leagues from the first team of the same soccer club in the north of Italy. The 2006 FIFA consensus statement was used to design the injury registration form.

RESULTS

Throughout the 2018-2019 season, medical staff treated 35 injuries in 22 females. Of the total number of injuries reported in 9 months (5.8 injuries per 1000 hours of exposure), 7 (20%) occurred during matches and 28 (80%) during training sessions. The most common injury was represented by muscular disorders (18; 51.43%) which affected the thigh in 16 cases, and the lower leg and trunk in one case each. According to an anatomic site, most injuries occurred in the lower limbs (94,28%), with the majority affecting thighs (16; 45%), ankles (8; 23%), and knees (5; 14%).

CONCLUSIONS

Non-contact injuries are shown to be more frequent than contact injuries, which may be connected to the increasing athletic burden among athletes. Further prospective investigations are needed with a focus on prevention protocols.

Intra and inter-tester reliability of a novel device to assess gluteal muscle strength in professional football players

The aim of this study is to investigate inter-tester and intra-tester reliability of a novel clam test (CLAMT) for the measurement of gluteal muscle strength and to detect possible differences between CLAMT values in football players with and without a history of groin injuries. Twenty male football players participated in the test-retest and sixty-two male professional football players participated in the case-control study. Hip abductor maximal muscle strength was evaluated either using CLAMT or in a supine position with the hip in a neutral pose. For CLAMT, intraclass correlation coefficient (ICC) for inter-tester-intra-day reliability was 0.80 (95% CI: 0.60-0.90), with a standard error of measurement of 34.2 N. The intra-tester-intra-day ICC was 0.92 (95% CI: 0.87-0.95), with a standard error of measurement of 23.6 N. The inter-week ICC was 0.96 (95% CI: 0.92-0.98), with a standard error of measurement of 18.9 N. CLAMT showed lower (but not significant) strength values in football players with a history of groin injuries to non-injured players. CLAMT showed good to excellent levels of reliability, intraday and inter-week, with low standard errors of measurement while it was effective (possible) to identify residual weakness in players with previous groin injuries.

Delayed ankle muscle reaction time in female amateur footballers after the first 15 min of a simulated prolonged football protocol

PURPOSE

Ankle sprain injury rate is reported to be higher towards the end of a football match. Muscle fatigue may contribute to the delayed muscle reaction and subsequent injury. This study investigated the ankle muscle reaction time during a simulated, prolonged football protocol.

METHODS

Seven amateur female football players participated in a 105-min simulated, prolonged football protocol. An ankle muscle reaction test was conducted with a pair of ankle sprain simulators at a scheduled interval every 15-min. The reaction times of peroneus longus, tibialis anterior, and lateral gastrocnemius were collected using an electromyography system sampling at 1000 Hz. Repeated measures one-way multivariate analysis of variance with post-hoc paired t-tests were conducted to evaluate if the reaction time at each time point significantly differed from baseline. Statistical significance was set at p < 0.05 level.

RESULTS

Reaction times started from 40.5-47.7 ms at baseline and increased to 48.6-55.7 ms at the end. Reaction times significantly increased in all muscles after the first 15 min except for the dominant lateral gastrocnemius. Increased reaction times were seen in the non-dominant limb after 60 min for tibialis anterior, after 75 min for peroneus longus, and after 90 min for the lateral gastrocnemius.

CONCLUSIONS

Delayed reaction time of the ankle muscles were found after the first 15 min and in the final 45 min of a simulated prolonged football protocol. Strategies for injury prevention should also focus on tackling the delayed ankle muscle reaction time in the acute phase (the first 15 min), in addition to the latter minutes in the second half.

LEVEL OF EVIDENCE

Controlled laboratory study, Level V.

Epidemiology of Injuries in Elite Female Futsal Players: A Prospective Cohort Study

Injuries are one of the worst case scenarios for an athlete and a team. The aim of this study was to analyze the injury incidence, characteristics and burden among a cohort of elite female futsal players. A prospective cohort study was designed over a season. Eighty-nine players from seven elite female futsal teams were monitored during the whole season. Eight different variables were recorded when an injury happened, as well as exposure time. A total of 90 injuries were recorded so that 54 out of 89 players (60.6%) sustained an injury. The overall injury incidence was 5 injuries per 1000 h of futsal play exposure. Moderate injuries were the most frequent (1.7 injuries per 1000 h of futsal play exposure). The quadriceps and ankle were the regions where most injuries occurred. Contact injuries were more common during matches than training, and usually happened at the end of the season. Elite female futsal players are exposed to a substantial injury risk, especially on ankle and quadriceps with moderate severity, occurring at the end of the sessions, especially during matches. These results highlight the need of new preventive strategies to reduce the high injury incidence in female futsal players.

Age-related changes in proprioception of the ankle complex across the lifespan

BACKGROUND

Ankle complex proprioceptive ability, needed in active human movement, may change from childhood to elderly adulthood; however, its development across all life stages has remained unexamined. The aim of the present study was to investigate the across-the-lifespan trend for proprioceptive ability of the ankle complex during active ankle inversion movement.

METHODS

The right ankles of 118 healthy right-handed participants in 6 groups were assessed: children (6-8 years old), adolescents (13-15 years old), young adults (18-25 years old), middle-aged adults (35-50 years old), old adults (60-74 years old), and very old adults (75-90 years old). While the participants were standing, their ankle complex proprioception was measured using the Active Movement Extent Discrimination Apparatus.

RESULTS

There was no significant interaction between the effects of age group and gender on ankle proprioceptive acuity (F (5, 106) = 0.593, p = 0.705, η² _p = 0.027). Simple main effects analysis showed that there was a significant main effect for age group (F (5, 106) = 22.521, p < 0.001, η ² _p = 0.515) but no significant main effect for gender (F (1,106) =  2.283, p = 0.134, η ² _p = 0.021) between the female (0.723 ± 0.092, mean ± SD) and the male (0.712 ± 0.083) participants. The age-group factor was associated with a significant linear downward trend in scores (F (1, 106) = 10.584, p = 0.002, η ² _p = 0.091) and a strong quadratic trend component (F (1,106) = 100.701, p < 0.001, η ² _p = 0.480), producing an asymmetric inverted-U function.

CONCLUSION

The test method of the Active Movement Extent Discrimination Apparatus is sensitive to age differences in ankle complex proprioception. For proprioception of the ankle complex, young adults had significantly better scores than children, adolescents, old adults, and very old adults. The middle-aged group had levels of ankle proprioceptive acuity similar to those of the young adults. The scores for males and females were not significantly different. Examination of the range of the scores in each age group highlights the possible level that ankle complex movement proprioceptive rehabilitation can reach, especially for those 75-90 years of age.

Patellofemoral Joint Loads during Running Immediately Changed by Shoes with Different Minimalist Indices: A Cross-sectional Study

Purpose: Given the high incidence of patellofemoral pain syndrome (PFPS) in runners, this study aimed to investigate the immediate effect of shoes with different minimalist indices (MI) on the mechanical loads of the patellofemoral joint. Methods: Fifteen healthy male rearfoot strike runners were recruited to complete overground running trials at 3.33 m/s (±5%) in two running shoe conditions (MI = 26% versus MI = 86%). The amount of ten Vicon infrared cameras (100 Hz) and two Kistler force plates (1000 Hz) were used to collect kinematic and ground reaction force (GRF) data simultaneously. Quadriceps strength, patellofemoral contact force, patellofemoral contact area, and patellofemoral contact stress were calculated. Results: No significant differences were observed in the impact force and the second peak of the vertical GRF between the two shoe conditions. Compared to wearing low-MI shoes, wearing high-MI shoes showed that the maximum flexion angle of the knee, the contact area of patellofemoral joint and the peak knee extension moment reduced significantly (p < 0.01), and the peak patellofemoral contact force and stress decreased significantly (p < 0.05). Conclusion: These findings suggest that wearing high-MI shoes significantly decreases the patellofemoral contact force and patellofemoral joint stress by reducing the moment of knee extension, thus effectively reducing the load of the patellofemoral joint during the stance phase of running and potentially lowering the risk of PFPS.

The Lysholm score: Cross cultural validation and evaluation of psychometric properties of the Spanish version

Background

This study aims at assessing the validity and reliability of the Spanish version of the Lysholm score, a widely used instrument for assessing knee function and activity level after ligament injuries.

Methods

Ninety-five participants (67.4% male, 22±5 years) completed the questionnaire twice within 7 days and a subsample of 42 participants completed a test-retest reliability. Reliability, validity and feasibility psychometric properties were studied. The validity of the questionnaire was analysed using ceiling and floor effects. Factor structure and construct validity were analysed with the SF-36, the Hip and Knee Questionnaire (HKQ) and one leg jump test (OLJT).

Results

Criterion validity with the SF-36 Physical State was moderate (r = 0.50 and p<0.01), poor and inverse relationship (r = -0.31, p<0.01) with HKQ and positive moderate (r = 0.59, p<0.01) with OLJT. Measurement error from MDC₉₀ was 3.9%. Exploratory factor analysis demonstrated a one-factor solution explaining 51.5% of total variance. The x2 test for the one-factor model was significant (x2 = 29.58, df = 20, p < 0.08). Test-retest reliability level was high (ICC2.1 = 0.92, p<0.01) and also the internal consistency (α = 0.77).

Conclusion

The Spanish Lysholm score demonstrated that it is a reliable and valid instrument that can be used to assess knee function after ligament injuries.

Changes in Lower-Limb Biomechanics, Soft Tissue Vibrations, and Muscle Activation During Unanticipated Bipedal Landings

We aimed to explore the biomechanical differences between the anticipated drop jump and unanticipated drop landing. Twelve male collegiate basketball players completed an anticipated drop jump and unanticipated drop landing with double legs from a height of 30 cm. Kinematics, impact force, soft tissue vibrations, and electromyographic (EMG) amplitudes of the dominant leg were collected simultaneously. The anticipated drop jump showed more flexed lower limbs during landing and increased range of motion compared to the unanticipated drop landing. The anticipated drop jump also had lower impact force, lesser soft tissue vibration, and a greater damp coefficient at the thigh muscles compared with the unanticipated drop landing. Significant increases in the EMG amplitudes of the tibialis anterior, lateral gastrocnemius, rectus femoris, and biceps femoris were observed in the anticipated drop jump during the pre/post-activation and downward phases. The anticipated drop jump presented more optimized landing posture control with more joint flexion, lower impact force, less soft tissue vibrations, and full preparation of muscle activations compared with the unanticipated drop landing.

Injury prevalence and risk factors in a Greek team's professional football (soccer) players: a three consecutive seasons survey

This study investigated the prevalence and risk factors of injuries on a cohort of 123 Greek team's professional football players during three consecutive seasons, 2015/16-to-2017/18. Injuries were assessed and regression analysis was used to evaluate the potential risk factors. Three-quarters of the players were recorded as injured with 2.3 injuries/injured player, and the injury incidence was 55 injuries/1,000 match-playing-exposure-hours. The mean rehabilitation days were 29.3/injured player (95%CI 22.4-36.8) and 13.0/injury (95%CI 8.6-17.4). The majority of injured players has been found to have moderate-to-major/severe injuries and most of the injuries were traumatic than overuse (p < 0.05). The number of injuries were related to the recurrence of injury (beta = 0.646, p < 0.001) and the rehabilitations days (beta = 0.271, p < 0.001). High prevalence of injuries was found as the recurrence of injury and rehabilitation days were their main predictive risk factors. In order to reduce the risk of injuries, continuous effort is required in the rehabilitation of players.