Non-contact Knee Research Articles

The relationship of hip strength and dynamic knee valgus during single leg squat in physically active females

BackgroundSingle leg squat (SLS) is an important motion commonly observed in sports. Excessive dynamic knee valgus (DKV) during SLS may increase non-contact knee injury risks particularly in physically active females. As muscular strength plays crucial role in controlling DKV, the present study aims to evaluate the correlation between hip strength and knee frontal plane angle during SLS among females with and without excessive DKV. MethodsThirty-four volunteers were allocated to the valgus (n = 17) and non-valgus (n = 17) groups. Their motions during SLS at 45° and 60° knee flexion were captured and analyzed using three-dimensional motion analysis system. Isokinetic hip strength was examined at 180°/s in flexion, extension, abduction, and adduction for both legs. Pearson's correlation test was computed to evaluate the relationship between hip strength and knee angle during SLS. FindingsNon-dominant hip extensor strength (r = −0.56, p = 0.02) and dominant hip adductor strength (r = −0.51, p = 0.04) were significantly related to the knee frontal plane angle during 45° SLS among those without DKV. Meanwhile, those with DKV showed a significant relationship between the knee frontal plane angle for both legs and non-dominant hip abductor strength during 60° SLS. InterpretationBoth groups demonstrated the relationship of hip strength on knee frontal plane angle during SLS, whereby increased hip strength may minimize excessive DKV. Those with excessive DKV should train to strengthen their hip abductor to reduce knee valgus particularly during deep squats.

Between 2008 and 2022, Lower-Extremity Injuries Declined in Male Rugby Players, Whereas Noncontact Knee Injuries Showed No Decline in Female Rugby Players

PurposeThe purpose of this study was to assess the distribution and mechanisms of lower extremity injuries among high school and college age rugby players presenting to United States (US) emergency departments (EDs) from 2008 to 2022. MethodsThe National Electronic Injury Surveillance System (NEISS) was queried for lower extremity rugby injuries (ages 14-23) from January 2008 to December 2022. Patient demographics, injury location, diagnosis, and disposition were extracted for each case. Linear regression analysis assessed differences over time. Injury distribution for males versus females was evaluated using Pearson’s chi-square analysis. ResultsAn estimated 31,318 (845 NEISS cases) high school and college-age rugby players presented to US EDs with a lower extremity injury during the study period. Males accounted for 66.9% of the injuries. Linear regression analysis revealed a significant decrease in annual frequency of lower extremity injuries presenting to US EDs from 2008 to 2022 (p=0.001). The most common injury mechanism was overwhelmingly a non-contact twisting motion (11,108, 35.5%) followed by a hit/collision (5,298, 16.9%). Strains/sprains were the most common diagnosis (17,243, 55.1%). Injuries most commonly occurred at the ankle (12,659, 40.4%) and knee (11,016, 35.2%). In a sex-specific linear regression analysis, there was a significant decrease in lower extremity injuries sustained by male players (p=0.001), but no significant decrease among female players (p=0.112). Furthermore, chi-squared analysis revealed that females sustained a significantly higher proportion of knee injuries secondary to twists (15.9% for females vs. 9.0% for males, p=0.01). ConclusionLower extremity injuries are declining among high school and college-age male rugby players. However, there has not been a corresponding decrease among female rugby players. Furthermore, females are disproportionately affected by non-contact twisting knee injuries.

Team Approach: Neuromuscular Training for Primary and Secondary Prevention of Anterior Cruciate Ligament Injury.

Neuromuscular training is a method of performance optimization-typically combining plyometrics, balancing training, agility, and dynamic stabilization-predicated on improving the efficiency of fundamental movement patterns. Neuromuscular training has consistently been shown to reduce the risk of anterior cruciate ligament injury, particularly for athletes engaged in activities associated with noncontact knee injuries (i.e., women's soccer). Successful implementation of neuromuscular training programs requires input from coaches, physical therapists, athletic trainers, and physicians to generate efficacious programs with high rates of adherence.

Decreased sagittal slope of the medial tibial spine and deep concavity of the lateral tibial spine are risk factors for noncontact anterior cruciate ligament injury.

This study aimed to assess the relationship between the geometric features of tibial eminence and susceptibility to noncontact anterior cruciate ligament (ACL) injuries. Patients with unilateral noncontact knee injuries between 2015 and 2021 were consecutively enroled in this study. Based on knee magnetic resonance imaging (MRI) and arthroscopic visualisation, patients were categorised into the case group (ACL rupture) and control group (ACL intact). Using MRI, the geometric features of tibial eminence were characterised by measuring the sagittal slopes, depth of concavityand coronal slopes of the inclined surfaces of the tibial spines. Univariate and multivariate logistic regressions were conducted to explore independent associations between quantified geometric indices of tibial eminence and the risk of noncontact ACL injuries. This study included 187 cases and 199 controls. A decreased sagittal slope of the medial tibial spine (MTSSS) (combined group: odds ratio [OR]: 0.87 [0.82, 0.92], p < 0.001; females: OR: 0.88 [0.80, 0.98], p = 0.020; males: OR: 0.87 [0.81, 0.93], p < 0.001) and an increased depth of concavity in the lateral tibial spine (LTSD)(combined group: OR: 1.51 [1.24, 1.85], p < 0.001; females: OR: 1.65 [1.12, 2.43], p = 0.012; males: OR: 1.44 [1.11, 1.89], p = 0.007) were independent risk factors for noncontact ACL injuries. Moreover, a steeper coronal slope of the inclined surface of the medial tibial spine was a significant predictor of noncontact ACL injuries for males (MTSCS: OR: 1.04 [1.01, 1.08], p = 0.015) but not for females. Geometric features of tibial eminence, particularly a decreased MTSSS and an increased LTSD, were identified as independent risk factors for noncontact ACL injuries. These findings will help clinicians identify individuals at high risk of ACL injury and facilitate the development of targeted prevention strategies. Level III.

Knee Laxities Changes with Sex-steroids throughout the Menstrual Cycle Phases in Athlete and Non-athlete Females.

Objective: Our study investigated changes of knee laxities in athletes and non-athletes females and relationship between knee laxity and sex-steroid at menstrual cycle phases. Methods: Forty six healthy females, twenty four athletes and twenty two non-athletes not on hormone contraceptive pills, had no previous knee injuries and with regular menstrual cycles for 3 consecutive months, participated in the study. Medial and lateral knee laxities were determined by varus-valgus tests at follicular, ovulatory and luteal phases. Serum level of relaxin, estrogen, progesterone and testosterone were determined by ELISA and radioimmunoassay. Results: Knee laxities in athletes and non-athletes at 0° and 20° flexion were the highest in luteal phase with non-athletes possess greater laxity than athletes. Positive correlation between progesterone and relaxin levels with knee laxities were observed. Meanwhile, the levels of both hormones were highest in the luteal phase. Conclusion: Increased medial and lateral knee laxities in athletes and non-athletes associated with high serum progesterone and relaxin levels in luteal phase may contribute toward increased risk of non-contact knee injury. However, lower knee laxity in athletes than non-athletes suggest that exercise could be a protective factor.

The effect of bisphosphonate and platelet-rich plasma in anterior cruciate ligament reconstruction: an article review

Link of Video Abstract: https://youtu.be/fn9kA601YVo ACL rupture is a common injury often resulting from previously healthy individuals' non-contact knee injuries. ACL rupture in young adults and teenagers are becoming more common, contrary to earlier theories that suggested ACL damage was uncommon in skeletally immature people. This risk is significantly raised by concomitant meniscal injury whether or not an ACL reconstruction is undertaken. Although surgical management with allograft or autograft reconstruction can be achieved successfully, there are some serious complications following ACL reconstruction. The supply of autografts is limited, especially in situations with numerous ligament injuries or re-ruptures, which might result in morbidity at the donor site. Allografts can increase the spread of illness and trigger an inflammatory response, which is a drawback. There has been much interest in a tissue-engineered ACL graft because of these issues and current developments in bioengineering and regenerative medicine. According to recent research, following an ACL repair, the bone marrow density surrounding the knee area diminishes. Platelet Rich Plasma (PRP) and Bisphosphonate are the substrates that could ameliorate this phenomenon. Therefore, this review aims to compile evidence of PRP and bisphosphonate and its effect on the tendon-bone interface in ACL reconstruction.

Motor Control and Regularity of Menstrual Cycle in Ankle and Knee Injuries of Female Basketball Players: A Cohort Study.

Inadequate motor control facilitates ankle and knee injuries in female basketball. Although biomechanical analysis could help to detect it, aspects such as irregular menstruation make these associations controversial. We aimed to evaluate associations between 2D biomechanics during landing and proprioception with ankle and knee injuries of female basketball players, considering their menstruation regularity. Seventy-one players participated in this study. In the preseason, participants performed a drop-jump to obtain biomechanics during landing and a weight-bearing proprioception test. During the competitive season, all the non-contact ankle and knee injuries were registered. Data showed that 16% of players sustained an ankle or knee injury, being more frequent in players with irregular menstruation compared to regulars (22% vs. 13%, χ2 = 6.009, p = 0.050, d = 0.6). Players who sustained a left-side injury displayed higher left-side dynamic valgus during landing than uninjured players (χ2 = 25.88, p = 0.006, d = 1.5). The rest of the variables did not show any significant difference (p > 0.05). Monitoring 2D dynamic valgus from a drop-jump could help to detect inadequate motor control that may facilitate ankle or knee injuries of female basketball players, mainly for those with irregular menstruation. Proprioception seems not to be related to injuries.

Frontal plane lower extremity alignment in adolescent athletes with chronic hip adductor-related groin injury symptoms: A case-control study

ObjectiveTo compare trunk and lower extremity frontal plane projection angles (FPPA) during single leg squat (SLS) performance, perceived hip and groin function and symptoms, and isometric hip strength of adolescent athletes with chronic hip adductor-related groin injury (HARGI) symptoms and age, gender, and sport-matched healthy subjects. DesignCase-control study. SettingJunior Olympic Development Training Centre. ParticipantsTwenty-six athletes at 59.1 ± 60 weeks (range = 12–208 weeks) post-index grade II HARGI injury who had continued sport training (injury group) and 26 control group subjects. Main outcome measuresSLS trunk, hip, and knee FPPA, isometric hip strength standardized to bodyweight, and Copenhagen Hip and Groin Outcome Scores (HAGOS). ResultsThe injury group had greater bilateral knee FPPA, and greater injury side hip FPPA during maximum SLS. Injury group HAGOS subscale scores were lower than control group scores. Hip abductor, adductor, external rotator, and internal rotator strength was lower at the injury side of the injury group compared to the matched control group limb. Forward stepwise multiple regression analysis of the injury group found that 50% of injury side knee FPPA was predicted by hip internal rotator strength and time post-index HARGI; and 47% of injury side hip FPPA was predicted by other side hip flexor strength and the HAGOS function, sport and recreation subscale score (p = 0.002). ConclusionsGreater injury side hip and bilateral knee FPPA during maximum SLS, lower self-reported hip symptom and function scores, and less injury side hip abductor, adductor, external rotator and internal rotator strength suggests that adolescent athletes with chronic HARGI symptoms are at an increased risk for sustaining a non-contact knee injury. Impaired hip internal rotator strength at the side of the chronic HARGI was related to increased knee FPPA, and impaired hip flexor strength at the other side of the HARGI was related to increased hip FPPA. Findings support using SLS performance testing in this athlete group to help determine safe return to sport training readiness.

Poster 120: The Impact of the COVID-19 Pandemic on Injury Onset and Timing in Division 1 NCAA Athletes

Objectives:The spread of the coronavirus disease 2019 (COVID-19) in February and March of 2020 led to the delay or cancellation of major sporting leagues and events across the globe. Collegiate athletic competitions were postponed until the end of the 2020 calendar year and organized collegiate athletic practices and training camps throughout 2020 were either cancelled or significantly reduced in frequency. The impact of the COVID-19 pandemic on injury epidemiology in collegiate athletics has not yet been investigated. We aim to describe the types of athletic injuries sustained by high level collegiate athletes before and after the COVID-19 pandemic.Methods:The Pacific 12 (Pac-12) Health Analytics Program contains all injuries sustained by intercollegiate athletes in the Pac-12 conference. This database was queried for injuries that occurred across all sports from January 2019 to June 2021. For all sports, timing of injury onset (acute versus overuse), severity of injury, rate of procedural intervention, injury mechanism (contact versus non-contact), and likelihood of injury during the 4th quarter of competition (final 25% of competition) was compared between the season immediately preceding the COVID-19 pandemic and the season immediately after. In this database, injury timing is defined as overuse if symptom onset occurred more than 24 hours after the precipitating incident. Results were stratified by upper and lower extremity as well as sport. Sub group analyses were also performed on knee and shoulder injuries among athletes competing in sports with historically high rates of knee and shoulder injuries. Multivariate analysis including gender was performed.Results:A total of 12,319 sport-related injuries across 23 sports were identified. The overall proportion of injuries sustained during the 4th quarter of competition was higher in the post-pandemic season (28.5% vs. 25.9%, p=0.015) and the overall proportion of non-contact injury was higher in the post-pandemic season (46.1% vs. 39.8%, p<0.0001). These findings were replicated when stratifying by upper and lower extremity injury. In sports with traditionally high rates of knee injuries (football, soccer, basketball, lacrosse, gymnastics), there was a higher proportion of overuse knee injuries (21.2% vs. 14.5%, p=0.003) and a higher proportion of non-contact knee injuries (47.6% vs 37.4%, p<0.0001) sustained in the post-pandemic season. In sports with high rates of shoulder injuries (football, baseball, softball, gymnastics, swimming, volleyball), there was a higher proportion of shoulder injuries taking place in the final 25% of competition (27.2% vs. 18.8%, p=0.016)) and a higher proportion of non-contact shoulder injuries (37.6% vs. 24.9%, p<0.0001) sustained in the post-pandemic season. Multivariate analysis also demonstrated higher rates of non-contact (OR 1.28, p<0.0001) and overuse injuries (OR 1.30, p=0.001) observed in the post-pandemic season and showed that female gender was significantly associated with overuse injury (OR 1.92, p<0.0001), non-contact injury (OR 1.35, p<0.0001), season ending injury (OR 2.33, p=0.008), and decreased likelihood of procedural intervention (OR 0.55, p<0.0001).Conclusions:Compared with the season immediately preceding the COVID-19 pandemic, athletes competing in the post-pandemic season were at higher risk of non-contact injury and injury near the end of a competition. There was a higher risk of overuse knee injuries and non-contact knee and shoulder injuries in the post-pandemic season. These findings are the first to describe the effect of a global pandemic on an athlete’s injury risk profile upon return to sport and may be used to guide decisions regarding athlete workload and training.Table 1.Pre- and Post-pandemic Injury Characteristics in Division 1 NCAA AthletesTable 2.Proportion of Overuse Injuries in 10 Largest Pac-12 SportsTable 3.Proportion of Non-contact Injuries in 10 Largest Pac-12 Sports

Force Production Patterns of Muscles Surrounding Knee During Running and Cutting Maneuvers: A Musculoskeletal Modeling Approach

OBJECTIVES The purpose of this study was to investigate the force production patterns of individual muscles surrounding the knee during running (RUN) and cutting (CUT) tasks.METHODS Thirteen women (24.2±3.5 yrs, 162.8±6.0 cm, 55.3±6.2 kg) performed a series of running and cutting tasks. Running and cutting motions were recorded using a motion capture system and ground reaction force (GRF) was recorded using a force plate. Three-dimensional knee angle, ground reaction force, and knee joint moment were calculated using Visual3D software. OpenSim musculoskeletal modeling software was used to calculate the force of individual muscles including the medial hamstring, biceps femoris long head, biceps femoris short head, rectus femoris, vastus medialis, vastus lateralis, gastrocnemius medialis, and gastrocnemius lateralis. All data were analyzed for loading response (or weight acceptance), mid-stance, and final push-off periods, respectively and were compared between two tasks.RESULTS At loading response: external rotation angle, medial and vertical GRFs, and valgus moment for the CUT task were greater than those of the RUN task. Compared to the RUN task, the CUT task showed: 1) an increase in lateral hamstring muscle force at weight acceptance, 2) a decrease in hamstring muscle force and an increase in medial vastus muscle force at mid-stance, and 3) an increase in lateral gastrocnemius muscle force at final push-off.CONCLUSIONS Selective force production patterns of muscles surrounding the knee seem to offset the external load caused by the cutting motion. We anticipate that our results will provide basic data for future training programs designed to prevent noncontact knee injuries.

Specificity of isokinetic assessment in noncontact knee injury prevention screening: A novel assessment procedure with relationships between variables in amateur adult agility-sport athletes

ObjectivesTo present a new knee isokinetic assessment procedure linked to noncontact knee injury mechanisms and examine correlations between variables relevant to noncontact knee injury prevention screening (peak torque [PT, Nm], time-to-peak torque [TTPT, ms], angle-of-peak torque [APT, °], mean PT [MPT, Nm]). DesignCross-sectional. SettingSports medicine laboratory. ParticipantsThirty-four agility-sport athletes (male/female n = 18/16, age 24.1 ± 3.5yr, height 171.8 ± 9.6 cm, mass 70.6 ± 12 kg). Main outcome measuresPearson's/Spearman's correlation (r/rs), coefficient of determination (r2/rs2). ResultsMost correlations were statistically non-significant or statistically-significant with only weak-to-moderate coefficients. For both knee extension and flexion, PT and MPT were significantly and strongly correlated (r = 0.99, r2 = 0.98, p = 0.001). Graphical analyses revealed two datapoint clusters for knee flexion TTPT and APT. One cluster indicated some participants could generate knee flexor PT rapidly (<150 ms) at low knee flexion angles (<45°) and the other cluster indicated that other participants could not (>200 ms, >50°). ConclusionsIn this study, most isokinetic variables represented distinct knee neuromuscular characteristics. For both knee extension and flexion, only PT or MPT need be used to represent isokinetic maximal strength. Knee flexion TTPT and APT may have utility in noncontact knee injury prevention screening with amateur adult agility-sport athletes.

Implementing an Injury Prevention and Performance Enhancement Program During a Softball Season for Young Female Athletes

Female athletes are up to 6 times more likely than males to sustain a significant noncontact knee injury. Although many reasons for this difference have been discussed, neuromuscular variances are trainable and strength programming can reduce the risk of injury and enhance performance for such athletes. Unfortunately, although such programming exists, injury rates remain largely unchanged over the past 2 decades, meaning there is a need for practical integration. This article describes a specific plan intended to be highly practical that can be used in softball practices and games to enhance the delivery of injury prevention and sport performance training.

Relationship Between 3 Single-Leg Functional Performance Tests for Netball Noncontact Knee Injury Prevention Screening in Uninjured Female Adult Players.

Single- versus double-leg landing events occur the majority of the time in a netball match. Landings are involved in large proportions of netball noncontact knee injury events. Of all landing-induced anterior cruciate ligament injuries, most occur during single-leg landings. Knowledge of whether different single-leg functional performance tests capture the same or different aspects of lower-limb motor performance will therefore inform clinicians' reasoning processes and assist in netball noncontact knee injury prevention screening. To determine the correlation between the triple hop for distance (THD), single hop for distance (SHD), and vertical hop (VH) for the right and left lower limbs in adult female netball players. Cross-sectional. Local community netball club. A total of 23 players (age 28.7 [6.2]y; height 171.6 [7.0]cm; mass 68.2 [9.8]kg). There were 3 measured trials (right and left) for THD, SHD, and VH, respectively. Mean hop distance (percentage of leg length [%LL]), Pearson intertest correlation (r), and coefficient of determination (r2). Values (right and left; mean [SD]) were as follows: THD, 508.5 (71.8) %LL and 510.9 (56.7) %LL; SHD, 183.4 (24.6) %LL and 183.0 (21.5) %LL; and VH, 21.3 (5.2) %LL and 20.6 (5.0) %LL. All correlations were significant (P ≤ .05), r/r2 values (right and left) were THD-SHD, .91/.83 and .87/.76; THD-VH, .59/.35 and .51/.26; and SHD-VH, .50/.25 and .37/.17. A very large proportion of variance (76%-83%) was shared between the THD and SHD. A small proportion of variance was shared between the THD and VH (25%-35%) and SHD and VH (17%-25%). The THD and SHD capture highly similar aspects of lower-limb motor performance. In contrast, the VH captures aspects of lower-limb motor performance different to the THD or SHD. Either the THD or the SHD can be chosen for use within netball knee injury prevention screening protocols according to which is reasoned as most appropriate at a specific point in time. The VH, however, should be employed consistently alongside rather than in place of the THD or SHD.

Acute effects of an injury preventive warmup programme on unanticipated jump-landing-task performance in adult football players: A crossover trial

ABSTRACT In football, unpredictable events (e.g. unexpected landings) seem to play a crucial role in the mechanism of non-contact knee injuries. This study investigated the effects of a single bout of an injury preventive warmup protocol on biomechanical landing stability and decision-making quality during preplanned and unanticipated jump-landings. A crossover study on 18 male amateur football players was performed. The participants completed a standard (ergometer) and an injury-preventive warmup protocol (Prevent injury and Enhance Performance (PEP)) on two different test days. After each protocol, participants performed countermovement jumps with preplanned (landing side displayed before takeoff) and unanticipated (landing side shown after takeoff) single-leg landings on a force plate. Outcomes were landing stability (height and time of the maximum vertical ground reaction force (pGRF), centre of pressure (CoP), the number of standing errors (ground contact with free leg)) and decision-making quality (landing error (wrong foot) count). Carry-over and crossover-tests were performed to find potential between-condition-differences. No carry-over effects occurred (p > .05). The PEP led to a reduced CoP trace length (−18.4 ± 32.2%, p = .021) and earlier occurrence of pGRF (−4.72 ± 6.78%, p = .017) in the preplanned condition. No significant between-treatment-differences occurred within the unanticipated landings and decision-making quality (p > .05). The primarily neuromuscular warmup protocol affects landing stability in the preplanned condition. However, it does not seem to better prepare football players for unpredictable events than a standard warmup. Trial registration: German Clinical Trials Register identifier: DRKS00016942. Highlights Adapting movements rapidly to unanticipated external stimuli (e.g. unexpected landings) is crutial to prevent injuries in football It is unclear wether popular neuromuscular injury preventive warmup programmes (e.g. Prevent injury and Enhance Performance (PEP)) adaquatly prepare athletes for these situations Our study shows that the PEP warm up programme has acute effects on anticipated landing stability, but no influence on unanticipated landings or decision making quality Classic neuromuscular warm up programmes may not be the optimal choice to prepare athletes properly for the upcoming motor-cognitive demands in a football match

Change of Direction Biomechanics in a 180-Degree Pivot Turn and the Risk for Noncontact Knee Injuries in Youth Basketball and Floorball Players

Background: Studies investigating biomechanical risk factors for knee injuries in sport-specific tasks are needed. Purpose: To investigate the association between change of direction (COD) biomechanics in a 180-degree pivot turn and knee injury risk among youth team sport players. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 258 female and male basketball and floorball players (age range, 12-21 years) participated in the baseline COD test and follow-up. Complete data were obtained from 489 player-legs. Injuries, practice, and game exposure were registered for 12 months. The COD test consisted of a quick ball pass before and after a high-speed 180-degree pivot turn on the force plates. The following variables were analyzed: peak vertical ground-reaction force (N/kg); peak trunk lateral flexion angle (degree); peak knee flexion angle (degree); peak knee valgus angle (degree); peak knee flexion moment (N·m/kg); peak knee abduction moment (N·m/kg); and peak knee internal and external rotation moments (N·m/kg). Legs were analyzed separately and the mean of 3 trials was used in the analysis. Main outcome measure was a new acute noncontact knee injury. Results: A total of 18 new noncontact knee injuries were registered (0.3 injuries/1000 hours of exposure). Female players sustained 14 knee injuries and male players 4. A higher rate of knee injuries was observed in female players compared with male players (incidence rate ratio, 6.2; 95% CI, 2.1-21.7). Of all knee injuries, 8 were anterior cruciate ligament (ACL) injuries, all in female players. Female players displayed significantly larger peak knee valgus angles compared with male players (mean for female and male players, respectively: 13.9°± 9.4° and 2.0°± 8.5°). No significant associations between biomechanical variables and knee injury risk were found. Conclusion: Female players were at increased risk of knee and ACL injury compared with male players. Female players performed the 180-degree pivot turn with significantly larger knee valgus compared with male players. However, none of the investigated variables was associated with knee injury risk in youth basketball and floorball players.

CHANGE IN KNEE SEPARATION DISTANCE IN ADOLESCENT ATHLETES AFTER A 6-WEEK NEUROMUSCULAR TRAINING PROGRAM

Background:Existing neuromuscular injury prevention programs have relied principally on lower extremity strengthening, agility, cutting and landing technique to improve jump landing mechanics in order to prevent non-contact knee ligament injuries.Purpose:To determine whether a 6-week neuromuscular training program emphasizing core (back & hip) strengthening and dynamic balance exercises can significantly improve normalized knee separation distance (nKSD) during a standard counter-movement jump landing maneuver.Methods:Fourteen adolescent athletes (11 boys, 3 girls, ages 12-15) volunteered to undergo a 2 day/week, 6-week off-season training program. On the first day of training, the athletes underwent assessments that included 2 trials of a counter-movement jump from a 40cm platform. The tests were recorded using a video camera in the frontal plane. Using Dartfish motion analysis software, knee separation distance (KSD) was measured as the distance (cm) between the femoral condyles at the lowest point of the jump landing, and intertrochanteric distance (ITD) as the distance (cm) between the femoral trochanters. Normalized knee separation distance was computed as nKSD = KSD/ITD. The training program focused on three progressions; increasing difficulty of core strengthening exercises, balance exercises, and agility drills. One-hour training sessions were subdivided as follows; 5 min dynamic warm-up, 10 min stretching, 10 min body weight core exercises, 15 min balancing exercises, 10 min dumbbell core exercises, 15 minute agility drills, 5 min of rest/hydration breaks. The athletes repeated the counter-movement jump test at the end of the 6 weeks.Results:There was a significant improvement (t = 2.740, p = 0.017) in nKSD between post-test (0.789 + 0.372) and pre-test (0.683 + 0.323)Conclusion:A 6-week neuromuscular training program focused on core strengthening and balance significantly improved jump landing mechanics which may reduce the risk of knee ligament injury.

Noncontact Knee Ligament Injury Prevention Screening in Netball: A Clinical Commentary with Clinical Practice Suggestions for Community-Level Players.

Netball is a predominantly female team court-sport which is played worldwide. Netball is becoming more popular in the United States following its countrywide introduction to schools and community centers. A unique characteristic of netball is the footwork rule which restricts players to a one-step landing after catching the ball. Most netball landings are single-leg landings resulting in high vertical ground reaction forces and high skeletal tissue forces. Thus, high-risk landing events that have the biomechanical potential for injury occur frequently. Noncontact knee ligament injuries are common following a knee abduction collapse when landing. Because the consequences of noncontact knee ligament injury are profound, strategies are needed to mitigate the burden of such injury for players, teams, and society.The purpose of this clinical commentary is to demonstrate how theoretical principles, different types of research, and different levels of evidence underpin a rational clinical reasoning process for developing noncontact knee ligament injury prevention screening procedures in netball. The theoretical principles that are discussed in this commentary include injury control, the sequence of prevention, principles of screening in injury prevention, the multifactorial model of injury etiology, complex systems theory, and systems science. The different types of research that are reviewed include descriptive and analytic-observational studies. The different levels of evidence that are discussed include prospective studies, cross-sectional studies, and clinicians’ own kinesiological modelling. Subsequently, an integrated approach to the evidence-informed development of noncontact knee ligament injury prevention screening procedures is presented. Clinical practice suggestions include a selection of evidence-informed screening tests that are quickly and easily implemented with netball players in local communities. The need for repeated screening at strategic timepoints across a season/year is explained. Sports physical therapists will find this commentary useful as an example for how to undertake clinical reasoning processes that justify the content of screening procedures contributing to noncontact knee ligament injury prevention in community-level netball.Level of Evidence5

Nine typical injury patterns in German professional male football (soccer): a systematic visual video analysis of 345 match injuries

AimWe aimed to systematically analyse the videos of acute injuries in professional men’s football and describe typical injury patterns.MethodsInjuries were registered with the German statutory accident insurance for professional athletes...

The Influence of Asymptomatic Hypermobility on Unanticipated Cutting Biomechanics.

Generalized joint hypermobility is an important risk factor for knee injuries, including to the anterior cruciate ligament (ACL). Examining movement patterns specific to hypermobile individuals during sport-specific movements could facilitate development of targeted recommendations and injury prevention programs for this population. Asymptomatic hypermobile participants will present kinematics measures suggestive of a greater risk of noncontact knee or ACL injuries. Cross-sectional study. Level 3. Forty-two (15 asymptomatic hypermobile and 27 nonhypermobile) individuals performed unanticipated side-step cutting on their dominant and nondominant legs. Ankle, knee, hip, pelvis, and trunk angles in all planes of motion were collected during the first 100 ms after initial contact using a 3-dimensional infrared system. Precontact foot-ground angles were also extracted. Data from hypermobile and nonhypermobile groups were compared using multiple regression models with sex as a confounder. When nonsignificant, the confounder was removed from the model. Effect sizes (Hedge g) were calculated in the presence of significant between-group differences. Hypermobile individuals presented with lower minimum knee valgus angles with a mean difference of 3.5° (P = 0.03, Hedge g = 0.69) and greater peak knee external rotation angles with a mean difference of -4.5° (P = 0.04, Hedge g = 0.70) during dominant leg cutting, and lower peak ankle plantarflexion angles with a mean difference of 4.5° (P = 0.03, Hedge g = 0.73) during nondominant leg cutting compared with nonhypermobile individuals. Based on current scientific evidence, however, the identified differences are not crucial biomechanical injury risk factors that could predispose asymptomatic hypermobile individuals to noncontact knee or ACL injuries. Further research is needed to highlight differences between hypermobility groups. Knowledge of the differences between these groups may change the physical activity recommendations, prevention of injury, and rehabilitation approaches.

3T MRI-based anatomy of the anterolateral knee ligament in patients with and without an ACL-rupture: Implications for anatomical anterolateral ligament reconstruction

BackgroundAnterior cruciate ligament (ACL) rupture is often accompanied by an injury to the anterolateral ligament (ALL) of the knee. Detailed knowledge of the ALL attachments in ACL-ruptured patients is essential for an anatomical ALL reconstruction to avoid knee over-constraint and successfully treat the residual rotational instability. The aim of the present study was to investigate the three-dimensional (3D), topographic anatomy of the ALL attachment in both ACL-ruptured and ACL-intact patients using 3 Tesla magnetic resonance imaging (3T MRI). MethodsIn the present, retrospective case-control study, the magnetic resonance images of 90 knees with an ACL-rupture and 90 matched-controlled subjects, who suffered a non-contact knee injury without an ACL-rupture, were used to create 3D models of the knee. The femoral and tibial ALL footprints were outlined on each model, and their position was measured using an anatomical coordinate system. ResultsThe femoral origin of the ALL was located 4.9 ± 2.8 mm posterior and 3.8 ± 2.4 mm proximal to the lateral epicondyle in a non-isometric location in control subjects. In ACL-ruptured patients, it was located in a more posterior and distal, at 6.0 ± 1.9 mm posterior and 2.4 ± 1.7 mm proximal to the lateral epicondyle (p < 0.01), also in a non-isometric location. No difference was found in the tibial ALL insertion between groups. ConclusionThe femoral ALL origin was significantly different in ACL-ruptured patients compared to ACL-intact patients. The recommended femoral tunnel position for the anatomical ALL reconstruction, does not represent the femoral ALL origin in the ACL-ruptured knee.