Mari Leppänen

Stiff Landings Are Associated With Increased ACL Injury Risk in Young Female Basketball and Floorball Players

Background: Few prospective studies have investigated the biomechanical risk factors of anterior cruciate ligament (ACL) injury. Purpose: To investigate the relationship between biomechanical characteristics of vertical drop jump (VDJ) performance and the risk of ACL injury in young female basketball and floorball players. Study Design: Cohort study; Level of evidence, 3. Methods: At baseline, a total of 171 female basketball and floorball players (age range, 12-21 years) participated in a VDJ test using 3-dimensional motion analysis. The following biomechanical variables were analyzed: (1) knee valgus angle at initial contact (IC), (2) peak knee abduction moment, (3) knee flexion angle at IC, (4) peak knee flexion angle, (5) peak vertical ground-reaction force (vGRF), and (6) medial knee displacement. All new ACL injuries, as well as match and training exposure, were then recorded for 1 to 3 years. Cox regression models were used to calculate hazard ratios (HRs) and 95% CIs. Results: Fifteen new ACL injuries occurred during the study period (0.2 injuries/1000 player-hours). Of the 6 factors considered, lower peak knee flexion angle (HR for each 10° increase in knee flexion angle, 0.55; 95% CI, 0.34-0.88) and higher peak vGRF (HR for each 100-N increase in vGRF, 1.26; 95% CI, 1.09-1.45) were the only factors associated with increased risk of ACL injury. A receiver operating characteristic (ROC) curve analysis showed an area under the curve of 0.6 for peak knee flexion and 0.7 for vGRF, indicating a failed-to-fair combined sensitivity and specificity of the test. Conclusions: Stiff landings, with less knee flexion and greater vGRF, in a VDJ test were associated with increased risk of ACL injury among young female basketball and floorball players. However, although 2 factors (decreased peak knee flexion and increased vGRF) had significant associations with ACL injury risk, the ROC curve analyses revealed that these variables cannot be used for screening of athletes.

Overuse injuries in youth basketball and floorball

Background The popularity of team sports is growing among young people. High training volume and intensity may predispose young athletes to overuse injuries. Research to date has tended to focus on acute injuries rather than overuse injuries. The purpose of this study was to examine the occurrence, nature, and severity of overuse injuries in youth basketball and floorball, with the hypothesis that overuse injuries are frequent in youth team sports. Methods The study comprised a total of 401 Finnish team sports athletes (207 basketball and 194 floorball players). The data were collected using a detailed questionnaire. The participants (mean age 15.8±1.9 years) responded to the questionnaire covering information on overuse injuries during the previous 12 months. Results A total of 190 overuse injuries was reported (97 in basketball and 93 in floorball). In both sports, most of the injuries involved the lower extremities (66% and 55% of all injuries in basketball and floorball, respectively). In basketball, the most commonly injured site was the knee (44 cases, 45%). In floorball, the most commonly injured sites were the lower back/pelvis (36 cases, 39%) and knee (32 cases, 34%). Overuse injuries caused an average time loss from full participation of 26±50 (median 7) days in basketball and 16±37 (median 5) days in floorball. Conclusion Overuse injuries are a common problem in youth team sports, and often cause long-term absence from full participation. The findings suggest that injury reduction and training load monitoring strategies are needed in the field. More research using explicit prospective data collection is needed to better understand the problem.

Epidemiology of Overuse Injuries in Youth Team Sports: A 3-year Prospective Study

Prospective studies on overuse injuries and their impact on athletic training among youth team sports are scarce. The purpose of this study was to investigate the incidence, severity and player related risk factors of overuse injuries among young (12-20 years) basketball and floorball players. A total of 387 players participated in a 3-year prospective study. Each player completed a baseline questionnaire regarding their background information. Overuse injuries that prevented players to fully or partly participate in their regular training were collected. In all, 204 overuse injuries were registered (injury incidence 1.51 injuries/1 000 h of exposure; 95% CI 1.35-1.78). Most of the injuries involved the knee (35%) and lower back (21%), and were classified as severe (44%). Injury incidence was 1.51 (95% CI 1.2-1.82) and 1.61 (95% CI 1.32-1.91) in basketball and floorball, respectively. Incidence was significantly higher among female compared with male players (incidence rate ratio 1.58; 95% CI 1.20-2.09). Previous injury and playing at adult level were the strongest factors associated with occurrence of an overuse injury. In conclusion, overuse injuries of the knee and low back are relatively common in youth basketball and floorball. Effective prevention strategies as well as training load monitoring is needed in youth team sports.

Knee Control and Jump-Landing Technique in Young Basketball and Floorball Players

Poor knee alignment is associated with increased loading of the joints, ligaments and tendons, and may increase the risk of injury. The study purpose was to compare differences in knee kinematics between basketball and floorball players during a vertical drop jump (VDJ) task. We wanted to investigate whether basketball players, whose sport includes frequent jump-landings, exhibited better knee control compared with floorball players, whose sport involves less jumping. Complete data was obtained from 173 basketball and 141 floorball players. Peak knee valgus and flexion angles during the VDJ were analyzed by 3D motion analysis.Larger knee valgus angles were observed among basketball players (- 3.2°, 95%CI -4.5 to - 2.0) compared with floorball players (- 0.9°, 95%CI -2.3 to 0.6) (P=0.022). Basketball players landed with a decreased peak knee flexion angle (83.1°, 95%CI 81.4 to 84.8) compared with floorball players (86.5°, 95%CI 84.6 to 88.4) (P=0.016). There were no significant differences in height, weight or BMI between basketball and floorball players. Female athletes exhibited significantly greater valgus angles than males. This study revealed that proper knee control during jump-landing does not seem to develop in young athletes simply by playing the sport, despite the fact that jump-landings occur frequently in practice and games.

Prevalence of adolescent physical activity-related injuries in sports, leisure time, and school: the National Physical Activity Behaviour Study for children and Adolescents

BackgroundThe purpose of this study was to investigate the prevalence of adolescent physical activity-related injuries in sports club activities, leisure time physical activity and school-based physical activity. The secondary aim was to investigate the differences in the prevalence of physical activity -related injuries between years 2014 and 2016. In addition, we set out to study the associations between age, sex and the frequency of physical activity and injury prevalence.MethodsThis cross-sectional study is based on the National Physical Activity Behaviour Study for Children and Adolescents (LIITU in Finnish) conducted in years 2014 and 2016. The subjects completed an online questionnaire in the classroom during school hours. A total of 8406 subjects participated in the current study. Out of these, 49% were boys and 51% were girls. The proportions of 11-, 13-, and 15-year-olds were 35%, 34% and 31%, respectively.ResultsIn the combined data for 2014 and 2016, injury prevalence was higher in sports club activities (46%, 95% CI 44.8–47.8) than in leisure time PA (30%, 95% CI, 28.5–30.5) or school-based PA (18%, 95% CI, 17.4–19.1). In leisure time PA, the injury prevalence was higher than in school-based PA. In all the three settings, injury prevalence was higher in 2016 than in 2014. Frequency of PA was associated with a higher risk for PA-related injuries in sports clubs and leisure time.ConclusionsWith half of the subjects reporting at least one PA-related injury during the past year, results indicate that adolescent PA-related injuries are a large-scale problem. There is a worrisome rise in injury prevalence in recent years. From a public health standpoint, there is an urgent need to invest in injury prevention to reverse this trend.

Overuse injuries are prevalent in children’s competitive football: a prospective study using the OSTRC Overuse Injury Questionnaire

Objectives To investigate the prevalence and burden of overuse injuries in children’s football as well as player characteristics and their association with overuse injury risk. Methods This investigation is based on the control arm (10 clubs) of a randomised controlled trial investigating prevention of injuries in youth football. We conducted a prospective 20-week follow-up study on overuse injuries among Finnish football players (n=733, aged 9–14 years). Each week, we sent a text message to players’ parents to ask if the player had sustained any injury during the past week. Players with overuse problem were interviewed over the phone using an overuse injury questionnaire. The main outcome measures were prevalence of all overuse injuries and substantial overuse injuries (those leading to moderate or severe reductions in participation or performance) and injury severity. Results The average response rate was 95%. In total, 343 players (46.8%) reported an overuse problem while in the study. The average weekly prevalence of all overuse problems and substantial overuse problems was 12.8% and 6.0%, respectively. Injuries affecting the knee had the highest weekly prevalence (5.7% and 2.4% for all and substantial knee problems, respectively). Girls had a higher likelihood of knee problems (OR 2.70; 95% CI 1.69 to 4.17), whereas boys had a higher likelihood of heel problems (OR 2.82; 95% CI 1.07 to 7.44). The likelihood of reporting an overuse problem increased with age (OR 1.21; 95% CI 1.00 to 1.47). Conclusion Overuse injuries are prevalent in children’s competitive football. Knee overuse injuries represent the greatest burden on participation and performance. Trial registration number ISRCTN14046021.

Sagittal Plane Hip, Knee, and Ankle Biomechanics and the Risk of Anterior Cruciate Ligament Injury :A Prospective Study

Background: Stiff landings with less knee flexion and high vertical ground-reaction forces have been shown to be associated with an increased risk of anterior cruciate ligament (ACL) injury. The literature on the association between other sagittal plane measures and the risk of ACL injuries with a prospective study design is lacking. Purpose: To investigate the relationship between selected sagittal plane hip, knee, and ankle biomechanics and the risk of ACL injury in young female team-sport athletes. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 171 female basketball and floorball athletes (age range, 12-21 years) participated in a vertical drop jump test using 3-dimensional motion analysis. All new ACL injuries, as well as match and training exposure data, were recorded for 1 to 3 years. Biomechanical variables, including hip and ankle flexion at initial contact (IC), hip and ankle ranges of motion (ROMs), and peak external knee and hip flexion moments, were selected for analysis. Cox regression models were used to calculate hazard ratios (HRs) with 95% CIs. The combined sensitivity and specificity of significant test variables were assessed using a receiver operating characteristic (ROC) curve analysis. Results: A total of 15 noncontact ACL injuries were recorded during follow-up (0.2 injuries/1000 player-hours). Of the variables investigated, landing with less hip flexion ROM (HR for each 10° increase in hip ROM, 0.61 [95% CI, 0.38-0.99]; P < .05) and a greater knee flexion moment (HR for each 10-N·m increase in knee moment, 1.21 [95% CI, 1.04-1.40]; P = .01) was significantly associated with an increased risk of ACL injury. Hip flexion at IC, ankle flexion at IC, ankle flexion ROM, and peak external hip flexion moment were not significantly associated with the risk of ACL injury. ROC curve analysis for significant variables showed an area under the curve of 0.6, indicating a poor combined sensitivity and specificity of the test. Conclusion: Landing with less hip flexion ROM and a greater peak external knee flexion moment was associated with an increased risk of ACL injury in young female team-sport players. Studies with larger populations are needed to confirm these findings and to determine the role of ankle flexion ROM as a risk factor for ACL injury. Increasing knee and hip flexion ROMs to produce soft landings might reduce knee loading and risk of ACL injury in young female athletes.

LANDING WITH LESS HIP FLEXION IS ASSOCIATED WITH INCREASED RISK OF ACL INJURIES IN YOUNG FEMALE TEAM SPORTS PLAYERS

Background Stiff landings with less knee flexion and high vertical ground reaction force have shown to be associated with increased risk of ACL injuries (Leppänen et al. 2016). The association between other sagittal plane measures and the risk of ACL injuries is less studied in prospective study designs. Objective To investigate the relationship between selected sagittal plane hip, knee, and ankle biomechanics and the risk of ACL injuries in young female team sport players. Design Prospective cohort study. Setting Female youth team sports. Participants A total of 171 female basketball and floorball players (aged 12–21) participated in a VDJ test using 3D motion analysis. All new ACL injuries, as well as match and training exposure, were recorded for 1 to 3 years. Assessment of Risk Factors The following biomechanical variables were analysed: 1) peak knee extension moment, 2) peak hip flexion angle, 3) peak hip extension moment, and 4) peak ankle dorsiflexion angle. Cox regression models were used to calculate hazard ratios (HRs, adjusted for 10 unit change) and 95% confidence intervals (CIs). Main Outcome Measurements Non-contact ACL injuries. Results Subjects suffered a total of 15 ACL injuries during the follow-up (0.2 injuries per 1 000 player hours). Of the investigated variables, landing with decreased hip flexion was significantly associated with increased risk of ACL injury (HR 0.60; 95% CI 0.37 to 0.97, P=0.038). Peak knee extension moment (HR 1.13; 95% CI 0.79 to 1.62, P=0.490), peak hip extension moment (HR 0.88; 95% CI 0.77 to 1.01, P=0.065), and peak ankle dorsiflexion angle (HR 0.70; 95% CI 0.33 to 1.51, P=0.360) were not significantly associated with ACL injuries. Conclusions Landing with less hip flexion may increase the risk of ACL injury in young female team sport players. More studies with large study populations are needed to confirm these findings.

973 Knee control and jump-landing technique in young basketball and floorball players

Background Poor knee alignment is associated with increased loading of the joints, ligaments and tendons, and may increase the risk of injury. The study purpose was to compare differences in knee kinematics between basketball and floorball players during a vertical drop jump (VDJ) task. We wanted to investigate whether basketball players, whose sport includes frequent jump-landings, exhibited better knee control compared with floorball players, whose sport involves less jumping. Methods Players (aged 12–21 years) were recruited from six basketball and floorball clubs of the Tampere City district, Finland. Complete data was obtained from 173 basketball and 141 floorball players. Peak knee valgus and flexion angles during the VDJ were analysed by 3 D motion analysis. Results Larger knee valgus angles were observed among basketball players (−3.2º, 95% CI: −4.5 to −2.0) compared with floorball players (−0.9º, 95% CI: −2.3 to 0.6) (P = 0.022). Basketball players landed with a decreased peak knee flexion angle (83.1º, 95% CI: 81.4 to 84.8) compared with floorball players (86.5º, 95% CI: 84.6 to 88.4) (P = 0.016). There were no significant differences in height, weight or BMI between basketball and floorball players. The female athletes exhibited significantly (P < 0.001) larger peak knee valgus angles (−7.5º, 95% CI: −8.7 to −6.2) than the male athletes (3.4º, 95% CI: 2.1 to 4.6). Conclusions This study revealed that proper knee control during jump-landing does not seem to develop in young athletes simply by playing the sport, despite the fact that jump-landings occur frequently in practice and games. Poor knee control was especially common among young female athletes. An important clinical implication of these findings is that young team sport athletes need to be taught a safer technique for landing and also need specific neuromuscular training in order to avoid potentially harmful movement patterns. (Int J Sports Med 2015, accepted for publication)

SELF-REPORTED 12-MONTH OVERUSE INJURY HISTORY IN YOUTH BASKETBALL AND FLOORBALL

Background The popularity of organized sports, especially team sports is growing among youth. High training volume and intensity at early age may predispose young athletes to overuse injuries. Objective To examine the occurrence, nature and severity of overuse injuries in youth basketball and floorball. Design A descriptive retrospective study. Setting Finnish youth basketball and floorball. Participants: 406 athletes (mean age 15.9, SD 2.0) from six basketball and floorball clubs (210 basketball and 196 floorball players). Main outcome measurements Self-reported history of overuse injuries over the preceding 12-month period. Data was obtained from a questionnaire. The severity of injuries was defined according to time-loss from full-time game or training. Results 172 overuse injuries (sustained by 139 players) were reported. Basketball players sustained 97 and floorball players 75 overuse injuries. Injury incidence in basketball was 1.1 and in floorball 0.8 injuries/1000h of exposure. Most of the overuse injuries involved the lower extremities (72% of all injuries). Most commonly injured site was the knee (45%). Another common site of the injury was the area of lower back/pelvis (26%), followed by the calf/shin (11%). No differences between the genders or the two sports were observed. Most of the injuries were slight (time-loss 1–3 days) injuries (33%). 23% of injuries were mild (time-loss 4–7 days), 20% were moderate (time-loss 8–28 days) and 25% of injuries were severe (time-loss ≥29 days) injuries. Overuse injuries caused an average time-loss of 24 days (SD 52). Conclusions Over a one third of the players participating in the study reported having sustained an overuse injury in the preceding 12 months. Remarkable proportion of overuse injuries were severe injuries. Overuse injuries often cause long absence from full-time game and training. Prospective studies to assess the risk factors and mechanisms of overuse injuries among youth team sports are needed.