Mari Leppänen

The purpose of this explorative study was to investigate the association between anatomic factors and risk for non‐contact anterior cruciate ligament (ACL) injuries among female team sport players. A total of 225 players from basketball, floorball, and volleyball aged 12–38 years (median 16) participated in baseline physical examination including measurements of static knee and pelvic alignment, leg length, pelvic width, and femoral and tibial condyle widths. Players were then prospectively followed for new ACL injuries for 2.5–4.5 years. Legs were analyzed separately. After excluding eight players with a history of ACL injury, the final sample included 217 players and 434 legs. Associations between variables of interest and ACL injury risk were analyzed using generalized linear mixed models with binomial distribution and player and club as random effects. During the follow‐up, 20 new non‐contact ACL injuries were registered. None of the measures investigated showed a significant relationship with the risk of new non‐contact ACL injuries. In conclusion, anatomic factors showed no association with increased risk of ACL injury in female team sport players.

Background Adherence may affect the effectiveness of injury prevention programmes (IPPs), yet no previous meta-analyses have examined the pooled impact of adherence to exercise-based IPPs across multiple injury types. The objective of the systematic review and meta-analysis was to investigate the effect of exercise-based IPP adherence on the risk of sports injuries. Methods Six databases (PubMed, EMBASE, SPORTDiscus, PEDro, Cochrane Central Register of Controlled Trials and Web of Science) were searched from inception to the end of May 2023. Randomised, quasi-randomised controlled trials and cluster-randomised controlled trials investigating exercise-based sports injury prevention interventions and providing data on adherence were included in the systematic review. Studies included in the meta-analysis were divided into top (≥84%), middle (74%–83%) and bottom (Results The top-adherence group had a 47% lower injury rate than the control group (rate ratio (RR)=0.53, 95% CI 0.42 to 0.67, pConclusions Higher adherence to IPPs resulted in reduced injury rates. When the adherence level was lower, the rate of injuries was not significantly reduced. PROSPERO registration number CRD42023429370.

The objective was to examine the prevalence, incidence rate, and burden of health problems among top-level female football players in Finland. During the four-season follow-up, altogether 372 players (mean age 20.6 years) from 13 teams participated. Players reported all health problems (sudden-onset injuries, gradual-onset injuries and illnesses) weekly using a mobile application. Training exposure was collected at the team level from coaches and individual match exposure from the match statistics. Prevalence, incidence rate, and burden of injuries and illnesses were calculated. The average weekly response rate was 87%. The weekly prevalence of any health problem was 23.1% (95% CI 21.0-25.3%). Prevalence of health problems causing moderate or severe modifications in sports participation/performance (substantial health problems) was 15.8% (95% CI 14.2-17.7%). Altogether 783 injuries (5.5 injuries per 1000 hours) and 586 illnesses (1.7 cases per 365 player-days) were reported. Seventy percent of injuries were sudden-onset (3.7 per 1000 hours) and 30% gradual-onset injuries (1.6 per 1000 hours). The incidence rate of sudden-onset injuries per 1000 hours was 2.3 (1.9-2.7) in training and 15.3 (11.2-21.0) in match play. Sudden-onset injuries accounted for 54% of total time loss, gradual-onset injuries 17%, and illnesses 30%. Thigh (19%) and ankle (18%) injuries were most common. Knee injuries, particularly ACL injuries, were the most severe, with knee injuries causing 53% and ACL injuries 28% of all injury time loss. Sudden-onset injuries, occurring mainly in matches, posed the greatest health burden for female football players.

The aim of this study was to investigate whether postural control was associated with an increased risk of future noncontact ACL injury in youth female basketball and floorball athletes. Data collection on 189 youth female basketball and floorball athletes was performed during a 3‐year period. The modified Star Excursion Balance Test (mSEBT), single‐leg drop‐down test, and single‐leg stance tests on a balance platform were used to measure postural control. In the mSEBT, performance in the anteromedial, medial, and posteromedial directions, as well as the corresponding composite score, were recorded. In balance platform tests, the mediolateral and anteroposterior velocity, velocity moment, and side length of a square representing 90% of postural sway were measured. Relative limb asymmetry and bilateral limb mean results for these variables were calculated and used as predictor variables in Cox regression analysis. Noncontact ACL injuries and individual exposure hours were prospectively recorded throughout the follow‐up. Twelve noncontact ACL injuries occurred. Greater limb asymmetry in the posteromedial direction [HR 1.18 (95% CI 1.05–1.32)] and composite score [HR 1.17 (95% CI 1.01–1.36)] on the mSEBT were associated with an increased risk of noncontact ACL injury. No statistically significant associations were found in the other directions for the mSEBT or any of the balance‐platform‐generated variables. Dynamic postural control, measured by limb asymmetry in the mSEBT, was associated with future ACL injury. Prevention programs for noncontact ACL injury could benefit from exercises directed toward correcting limb asymmetries in dynamic postural control in youth female basketball and floorball athletes.

Sufficient muscle strength is suggested to reduce frontal plane knee loading during change of direction maneuvers. However, it is currently not thoroughly understood if lower extremity strength is associated with increased frontal plane knee biomechanics during change of direction in youth female team sport players. The objective of this cross-sectional study was to investigate the influence of maximal muscle strength on knee valgus angle and knee abduction moment during 180° pivot turn in 106 youth female team sport players. Lower hip abductor strength, lower knee extensor strength, and higher knee flexor strength were associated with increased knee valgus. Higher knee flexor and leg press strength were associated with increased knee abduction moment. The study found associations between both decreased and increased lower extremity muscle strength and frontal plane knee biomechanics. However, these associations could explain only 20% of the variance in frontal plane knee biomechanics at best.

Purpose: To investigate whether six selected anatomical variables were associated with non‐contact anterior cruciate ligament (ACL) injury in female team sport athletes. Methods: Two hundred eighty‐seven female athletes (age 13–38 at baseline) from basketball, floorball, ice hockey and volleyball completed a baseline physical examination, including measurements of anterior‐posterior (AP) knee laxity, knee hyperextension, generalized joint hypermobility, femoral anteversion, hamstring extensibility and navicular drop. Athletes entered the study either in 2011, 2012 or 2013 and were followed up until the end of 2015. During the follow‐up, all complete and magnetic resonance‐verified ACL injuries were recorded. Results: Twenty‐three non‐contact ACL injuries were recorded. There were no significant differences in baseline physical examination variables between athletes who sustained ACL injuries and those who did not. However, a side‐to‐side difference in AP knee laxity greater than 2 mm was observed in 20% of the ACL injury group compared to 12% of the non‐injured group, although this difference was not statistically significant. Conclusions: In this study, AP knee laxity, knee hyperextension, generalized joint hypermobility, femoral anteversion, hamstring extensibility and navicular drop were not associated with increased risk for non‐contact ACL injury in female team sport athletes. This study was powered to detect moderate to strong risk associations; thus, smaller risk associations may not have been identified. Level of Evidence: Level II.

Objective: To compare the injury risk between natural grass and artificial turf in the male Finnish premier division (Veikkausliiga) matches during the 2019 league season. Design: A retrospective reanalysis of prospectively collected season-long injury surveillance cohort study. Setting: Finnish elite-level male football. Participants: All 12 teams of Veikkausliiga participated in the study. All players were eligible to participate. Two hundred thirty-six players took part in the follow-up between February and November 2019. Interventions: Matches were played between April and November 2019. Injury data were collected using standard injury reports from the team medicals and weekly player questionnaires. Individual player exposure in matches was collected. Artificial turf was classified as exposure and natural grass as control in the analyses. Main Outcome Measures: Match-related injury incidence and incidence rate ratios (IRR) with 95% confidence intervals (CI) on natural grass and artificial turf. Results: A total of 113 injuries (65 on artificial turf, 48 on natural grass) in 167 matches (90 on artificial turf, 77 on natural grass) were included. Injury incidence was 27.2/1000 hours on artificial turf and 23.9/1000 hours on natural grass and (IRR, 1.1; 95% CI, 0.8–1.7). There was no difference in injury types, anatomical regions, injury recurrence, injury severity, or injury contact. Forwards may have had an increased injury incidence on artificial turf compared with natural grass (IRR, 3.4; 95% CI, 1.0–11.8). Conclusions: This study supports previous reports that there is no significant increase in the overall risk of injury in professional football played on artificial turf compared with that on natural grass.

Objective This study aims to investigate the efficacy of two exercise interventions in reducing lower extremity (LE) injuries in novice recreational runners. Methods Novice runners (245 female, 80 male) were randomised into hip and core (n=108), ankle and foot (n=111) or control (n=106) groups. Interventions were completed before running and included exercise programmes focusing on either (1) hip and core or (2) ankle and foot muscles. The control group performed static stretching exercises. All groups were supervised by a physiotherapist and performed the same running programme. Injuries and running exposure were registered using weekly questionnaires during the 24-week study. Primary outcome was running-related LE injury. Results The incidence of LE injuries was lower in the hip and core group compared with the control group (HR 0.66; 95% CI 0.45 to 0.97). The average weekly prevalence of overuse injuries was 39% lower (prevalence rate ratio, PRR 0.61, 95% CI 0.39 to 0.96), and the prevalence of substantial overuse injuries was 52% lower (PRR 0.48, 95% CI 0.27 to 0.90) in the hip and core group compared with the control group. No significant difference was observed between the ankle and foot group and control group in the prevalence of overuse injuries. A higher incidence of acute injuries was observed in the ankle and foot group compared with the control group (HR 3.60, 95% CI 1.20 to 10.86). Conclusion A physiotherapist-guided hip and core-focused exercise programme was effective in preventing LE injuries in novice recreational runners. The ankle and foot programme did not reduce LE injuries and did not protect against acute LE injuries when compared with static stretching.

While the general reliability of the Y balance test has been previously found to be excellent, earlier reviews highlighted a need for a more consistent methodology between studies. The purpose of this test–retest intrarater reliability study was to assess the intrarater reliability of the YBT using different methodologies regarding normalisation for leg length, number of repetitions, and score calculation. Sixteen healthy adult novice recreational runners aged 18–55 years, both women and men, were reviewed in a laboratory environment. Mean calculated scores, intraclass correlation coefficient, standard error of measurement, and minimal detectable change were calculated and analysed between different leg length normalisation and score calculation methods. The number of repetitions needed to reach a plateauing of results was analysed from the mean proportion of maximal reach per successful repetition. The intrarater reliability of the YBT was found to be good to excellent, and it was not affected by the method of score calculation or leg length measurement. The test results plateaued after the sixth successful repetition. Based on this study, it is suggested to use anterior superior iliac spine–medial malleolus length for leg length normalisation because this method was proposed in the original YBT protocol. At least seven successful repetitions should be performed to reach a result plateau. The average of the best three repetitions should be used to mitigate possible outliers and account for the learning effects seen in this study.