The quest for dynamic consistency: a comparison of OpenSim tools for residual reduction in simulations of human running.

Using synchronous kinematic and kinetic data in simulations of human running typically leads to dynamic inconsistencies. Minimizing residual forces and moments is subsequently important to ensure plausible model outputs. A variety of approaches suitable for residual reduction are available in OpenSim; however, a detailed comparison is yet to be conducted. This study compared OpenSim tools applicable for residual reduction in simulations of human running. Multiple approaches (i.e. Residual Reduction Algorithm, MocoTrack, AddBiomechanics) designed to reduce residual forces and moments were examined using an existing dataset of treadmill running at 5.0 ms-1. The computational time, residual forces and moments, and joint kinematics and kinetics from each approach were compared. A computational cost to residual reduction trade-off was identified, where lower residuals were achieved using approaches with longer computational times. The AddBiomechanics and MocoTrack approaches produced variable lower and upper body kinematics, respectively, versus the remaining approaches. Joint kinetics were similar between approaches; however, MocoTrack generated noisier upper limb joint torque signals. MocoTrack was the best-performing approach for reducing residuals to near-zero levels, at the cost of longer computational times. This study provides OpenSim users with evidence to inform decision-making at the residual reduction step of their workflow.

Increased muscle force does not induce greater stretch-induced damage to calf muscles during work-matched heel drop exercise.

PURPOSE: To investigate the effect of muscle force during active stretch on quantitative and qualitative indicators of exercise-induced muscle damage (EIMD) in the medial gastrocnemius (MG) muscle. METHODS: Twelve recreationally active volunteers performed two trials of an eccentric heel drop exercise. Participants performed a single bout of low-load (body weight) and high-load (body weight + 30% body weight) exercises on separate legs. The total mechanical work output for each condition was matched between legs. Before, two hours and 48 h after each bout of eccentric exercise, electrically stimulated triceps surae twitch torque, muscle soreness, MG active fascicle length at maximum twitch torque and muscle passive stiffness were collected. Triceps surae electromyographic (EMG) activity, MG fascicle stretch and MG muscle-tendon unit (MTU) length were measured during the eccentric tasks. RESULTS: The high-load condition increased triceps surae muscle activity by 6-9%, but reduced MG fascicle stretch (p < 0.001). MTU stretch was similar between conditions. The greater muscle force during stretch did not give rise to additional torque loss (5 vs 6%) or intensify muscle soreness. CONCLUSIONS: Adding 30% body weight during eccentric contractions has a modest impact on exercise-induced muscle damage in the medial gastrocnemius muscle. These results suggest that muscle load may not be an important determinant of stretch-induced muscle damage in the human MG muscle. The muscle investigated does exhibit large pennation angles and high series elastic compliance; architectural features that likely buffer muscle fibres against stretch and damage.

Measurement error associated with gait cycle selection in treadmill running at various speeds.

A common approach in the biomechanical analysis of running technique is to average data from several gait cycles to compute a 'representative mean.' However, the impact of the quantity and selection of gait cycles on biomechanical measures is not well understood. We examined the effects of gait cycle selection on kinematic data by: (i) comparing representative means calculated from varying numbers of gait cycles to 'global' means from the entire capture period; and (ii) comparing representative means from varying numbers of gait cycles sampled from different parts of the capture period. We used a public dataset (n = 28) of lower limb kinematics captured during a 30-second period of treadmill running at three speeds (2.5 m s-1, 3.5 m s-1 and 4.5 m s-1). 'Ground truth' values were determined by averaging data across all collected strides and compared to representative means calculated from random samples (1,000 samples) of n (range = 5-30) consecutive gait cycles. We also compared representative means calculated from n (range = 5-15) consecutive gait cycles randomly sampled (1,000 samples) from within the same data capture period. The mean, variance and range of the absolute error of the representative mean compared to the 'ground truth' mean progressively reduced across all speeds as the number of gait cycles used increased. Similar magnitudes of 'error' were observed between the 2.5 m s-1 and 3.5 m s-1 speeds at comparable gait cycle numbers -where the maximum errors were < 1.5 degrees even with a small number of gait cycles (i.e., 5-10). At the 4.5 m s-1 speed, maximum errors typically exceeded 2-4 degrees when a lower number of gait cycles were used. Subsequently, a higher number of gait cycles (i.e., 25-30) was required to achieve low errors (i.e., 1-2 degrees) at the 4.5 m s-1 speed. The mean, variance and range of absolute error of representative means calculated from different parts of the capture period was consistent irrespective of the number of gait cycles used. The error between representative means was low (i.e., < 1.5 degrees) and consistent across the different number of gait cycles at the 2.5 m s-1 and 3.5 m s-1 speeds, and consistent but larger (i.e., up to 2-4 degrees) at the 4.5 m s-1 speed. Our findings suggest that selecting as many gait cycles as possible from a treadmill running bout will minimise potential 'error.' Analysing a small sample (i.e., 5-10 cycles) will typically result in minimal 'error' (i.e., < 2 degrees), particularly at lower speeds (i.e., 2.5 m s-1 and 3.5 m s-1). Researchers and clinicians should consider the balance between practicalities of collecting and analysing a smaller number of gait cycles against the potential 'error' when determining their methodological approach. Irrespective of the number of gait cycles used, we recommend that the potential 'error' introduced by the choice of gait cycle number be considered when interpreting the magnitude of effects in treadmill-based running studies.

Consensus on a netball video analysis framework of descriptors and definitions by the netball video analysis consensus group.

Using an expert consensus-based approach, a netball video analysis consensus (NVAC) group of researchers and practitioners was formed to develop a video analysis framework of descriptors and definitions of physical, technical and contextual aspects for netball research. The framework aims to improve the consistency of language used within netball investigations. It also aims to guide injury mechanism reporting and identification of injury risk factors. The development of the framework involved a systematic review of the literature and a Delphi process. In conjunction with commercially used descriptors and definitions, 19 studies were used to create the initial framework of key descriptors and definitions in netball. In a two round Delphi method consensus, each expert rated their level of agreement with each of the descriptors and associated definition on a 5-point Likert scale (1-strongly disagree; 2-somewhat disagree; 3-neither agree nor disagree; 4-somewhat agree; 5-strongly agree). The median (IQR) rating of agreement was 5.0 (0.0), 5.0 (0.0) and 5.0 (0.0) for physical, technical and contextual aspects, respectively. The NVAC group recommends usage of the framework when conducting video analysis research in netball. The use of descriptors and definitions will be determined by the nature of the work and can be combined to incorporate further movements and actions used in netball. The framework can be linked with additional data, such as injury surveillance and microtechnology data.

Video analysis of anterior cruciate ligament injury situations in the women's Australian football league.

BACKGROUND: Anterior cruciate ligament (ACL) injury rates in the Women's Australian Football League (AFLW) are alarmingly high. Understanding injuries within their sporting context is important to develop effective injury prevention strategies, yet there is currently little knowledge of how ACL injuries occur to AFLW players. This study addressed the common scenarios and characteristics of AFLW ACL injuries. METHODS: Online match and AFLW club injury reports identified 38 ACL injury cases. After excluding injuries where footage was unavailable (i.e. training, pre-season games), a video analysis of 21 match ACL injuries from the 2017-2020 AFLW seasons was performed. We examined match characteristics, and the player's movements and body postures preceding and at the estimated time of injury. Descriptive frequencies and relative proportions were determined across the assessed categories. RESULTS: Non-contact ACL injuries were frequently observed (n = 13, 61.9%), while contact preceding the injury event (i.e. indirect contact) was also common (n = 10, 47.6%). The most common game situation was direct defence (i.e. defending an opponent in possession) (n = 14, 66.7%). Sidestep cutting was the most prevalent movement (n = 11, 52.4%), with this commonly performed while applying defensive pressure (n = 6 of 11, 54.6%). CONCLUSION: Sidestep cutting when applying defensive pressure is the most common non-contact ACL injury scenario in the AFLW. Preceding contact potentially contributing to a player's loss of balance was another prominent AFLW scenario. AFLW players may benefit from injury prevention programs emphasising appropriate sidestep cutting technique during reactive defensive scenarios, and maintenance of lower limb postures known to withstand knee loading relative to the sporting task.

Epidemiology of injuries sustained in professional Australian netball: A three season cohort study.

OBJECTIVES: To report the medical attention and time-loss injury epidemiology of Australia's premier netball competition. DESIGN: Descriptive epidemiological study. METHODS: One-hundred and nineteen players in the Suncorp Super Netball league were under surveillance during three consecutive seasons (2017-2019), inclusive of pre-, in-, and post- season phases. Medical attention injuries were recorded by medical personnel, and additionally sub-categorised according to time loss. Injury incidence rates (IIR) and injury burden were calculated per 365 player contract days, with differences between season and season phase IIRs compared using negative binomial generated incidence rate ratios (IRR). RESULTS: Eight hundred and sixty-six medical attention injuries and 393 time-loss injuries were recorded. The majority of the players had multiple (≥2) medical attention (n = 92; 77.3%) and time-loss (n = 75, 63.0%) injuries reported. The ankle (n = 181; 20.9%), knee (n = 136; 15.7%) and foot (n = 98; 11.3%) were the body sites with the most frequently reported medical attention injuries. Overall, there was a comparable injury incidence rate between the pre-season and in-season periods (IRR = 1.13, 95%CI = 0.98-1.30, p = 0.0842), although variation in the injury burden was identified. Ankle tendon injuries (23.5 days absence) and knee joint injuries (44.9 days absence) the most burdensome injuries in the pre-season and in-season periods respectively. CONCLUSIONS: Lower limb injuries are the most frequent in professional level netball. Knee and ankle injuries are the most burdensome overall, however the type of injuries with a high burden vary between pre- and in-season periods. Time-loss, non-time loss and subsequent injuries are prominent in professional level netball.

Quantifying jumps and external load in netball using VERT inertial measurement units.

This study assesses the relationship between an inexpensive and an established inertial measurement device for the measurement of movement and jumps in netball. Twenty-five female netballers participated in this study (11 elite and 14 sub-elite). Two inertial measurement devices (Catapult ClearSky T6 and VERT Classic) were worn simultaneously during a training session. The 'Kinetic Energy' output provided by the VERT device was compared to the total PlayerLoad collected by the ClearSky T6 device. Automated total jump counts were also compared across devices. A correlation of r = 0.76 (95% confidence interval [CI]; 0.52 to 0.89) was identified between total PlayerLoad and 'Kinetic Energy'. Similarly, a correlation of r = 0.81 (95% CI; 0.61 to 0.91) was identified for the relationship between ClearSky T6 jump count and VERT jump count. Mean bias of 1.7 jumps (95% CI; -2.5 to 5.8) with 95% limits of agreement (-17.9 to 21.3) were found when comparing the jump counts between the ClearSky T6 and VERT devices. The correlations found in this study indicate that the VERT devices may be an accessible alternative for sub-elite athletes; however, the wide confidence intervals and limits of agreement warrant caution.

Kinematic and Coordination Variability in Individuals With Acute and Chronic Patellofemoral Pain.

Altered gait variability occurs in those with patellofemoral pain and may be relevant to pain progression. We examined gait kinematic and coordination variability between individuals with acute and chronic patellofemoral pain and healthy controls. Eighty-three patellofemoral pain runners (37 men and 46 women) and 142 healthy controls (52 men and 90 women) ran on a treadmill while 3-dimensional lower limb kinematic data were collected. Patellofemoral pain runners were split into acute (n = 22) and chronic (n = 61) subgroups based on pain duration (< and ≥3 mo, respectively). Approximate entropy assessed continuous hip, knee, and ankle kinematic variability. Vector coding calculated coordination variability for select joint couplings. Variability measures were compared between groups using 1-way analysis of variance and post hoc comparisons with Cohen d effect sizes. The chronic patellofemoral pain subgroup displayed higher frontal plane knee kinematic variability compared with controls (P = .0004, d = 0.550). No statistically significant effects for any coordination variability couplings were identified. Minimal differences in gait variability were detected between those with acute and chronic patellofemoral pain and healthy controls.

Movement intensity demands between training activities and competition for elite female netballers.

The aim of this study was to assess the differences in movement intensity demands between training activities and competition match-play in elite netball. Twelve elite female netballers (mean ± SD, age = 25.9 ± 5.1 years; height = 178.6 ± 8.9 cm, body mass = 71.1 ± 7.1 kg) competing in Australia's premier domestic netball competition participated. Data were collected across the season from all pre-season training sessions (n = 29), pre-season practice matches (n = 8), in-season training sessions (n = 21), in-season practice matches (n = 5), and competition matches (n = 15). Linear mixed-effects models assessed differences in PlayerLoad™ per minute and metreage per minute between activity types (Specialist, Skill Drills, Set-piece, Match Scenarios, Practice Match-play, and Competition Match-play) for positional groupings (Defenders, Midcourters, and Goalers). Competition Match-play resulted in higher (p < 0.05) PlayerLoad™ than all training activity types, with the largest magnitudes of difference between Specialist-Competition (d = 0.44-0.59; small to medium) and Skill Drills-Competition (d = 0.35-0.63; small to medium) for all positional groups. The smallest difference was found between Match Scenarios-Competition (d = 0.12-0.20; trivial to small) and Practice Match-play-Competition (d = 0.12-0.14; trivial). Competition Match-play also resulted in higher (p < 0.05) metreage per minute than Specialist (d = 0.23-0.53; small to medium), Skill Drills (d = 0.19-0.61; trivial to medium) and Set-piece (d = 0.05-0.31; trivial to small). Training activity demands in order of least to most similar to competition were specialist, skill drills, set-piece, match scenarios, and practice match-play. We provide data that enables coaches and physical preparation staff to incorporate progressions into their training session designs that can replicate the movement intensity demands of competition in training.

Simulating the effect of glenohumeral capsulorrhaphy on kinematics and muscle function.

This study aimed to use a predictive simulation framework to examine shoulder kinematics, muscular effort, and task performance during functional upper limb movements under simulated selective glenohumeral capsulorrhaphy. A musculoskeletal model of the torso and upper limb was adapted to include passive restraints that simulated the changes in shoulder range of motion stemming from selective glenohumeral capsulorrhaphy procedures (anteroinferior, anterosuperior, posteroinferior, posterosuperior, and total anterior, inferior, posterior, and superior). Predictive muscle-driven simulations of three functional movements (upward reach, forward reach, and head touch) were generated with each model. Shoulder kinematics (elevation, elevation plane, and axial rotation), muscle cost (i.e., muscular effort), and task performance time were compared to a baseline model to assess the impact of the capsulorrhaphy procedures. Minimal differences in shoulder kinematics and task performance times were observed, suggesting that task performance could be maintained across the capsulorrhaphy conditions. Increased muscle cost was observed under the selective capsulorrhaphy conditions, however this was dependent on the task and capsulorrhaphy condition. Larger increases in muscle cost were observed under the capsulorrhaphy conditions that incurred the greatest reductions in shoulder range of motion (i.e., total inferior, total anterior, anteroinferior, and total posterior conditions) and during tasks that required shoulder kinematics closer to end range of motion (i.e., upward reach and head touch). The elevated muscle loading observed could present a risk to joint capsule repair. Appropriate rehabilitation following glenohumeral capsulorrhaphy is required to account for the elevated demands placed on muscles, particularly when a significant range of motion loss presents.

When does risk outweigh reward? Identifying potential scoring strategies with netball's new two-point rule.

Changing rules to promote scoring through more 'high-risk' play has become common in team sports. Australia's national netball league (i.e. Suncorp Super Netball) has recently taken this approach-introducing a two-point shooting rule. Teams will be awarded two-points for shots made from an 'outer circle' 3.0m-4.9m from the goal in the final five minutes of quarters. We sought to answer a series of questions regarding the implementation and potential strategies surrounding the two-point rule in Suncorp Super Netball. We used video coded data from the 2018 Suncorp Super Netball season to identify the total number of made and missed shots from different distances across the season. We also used shooting statistics from recent Fast5 Netball World Series (a competition with a two-point shooting rule already in place) as a comparator. The reward of two-points is relatively well-aligned to the relative risk of missing shots from the proposed outer versus inner circle (2.22 [1.98, 2.48 95% CIs]) based on existing shooting data from Suncorp Super Netball teams. We found that the relative risk of missing shots from 'long-' (i.e. 3.5m-4.0m) versus 'mid-range' (i.e. 3.0-3.5m) was only slightly elevated (1.52 [1.21, 1.86 95% CIs])-suggesting teams should favour long- over mid-range shots when the two-point shot is available. Based on the typical number of shots a team receives in a five-minute period, we found that teams may be able to score ~3.51 extra points per quarter when taking all versus no-shots from the two-point outer circle. Analysis of the Fast5 versus Suncorp Super Netball data did, however, reveal that shooting accuracy from long-range may decrease when a two-point shot is available. Teams may need to consider situational factors (e.g. altered opposition defensive strategies) when developing their shooting strategy for taking advantage of the two-point shot.

Physical movement demands of elite-level netball match-play as measured by an indoor positioning system.

Physical movement demands in elite netball match-play have been limited to notational analysis or accelerometer-derived measures, due in part to the indoor environment in which they are played. Commercially available local positioning systems (LPS) using ultra-wideband communication have been designed to bring similar capabilities as global positioning systems (GPS) to indoor environments. This study aims to quantify both spatiotemporal and traditional accelerometer-derived measures, to assess the movement demands of all playing positions, during Australian national netball league matches. Total distance, metreage per minute, acceleration density, acceleration density index, acceleration load, jumps, velocity bands, acceleration bands and PlayerLoad variables have been presented for each position. Mean total distance-covered in match-play differed substantially between positions. Centre position accumulated the highest mean distance (5462.1 ± 169.4 m), whilst the Goal Shooter consistently covered the lowest mean distance (2134 ± 102.6 m). Change of direction relative to movement area was highest for the two most restricted positions based on average acceleration per 10 m covered during match-play (Goal Shooter; 7.21 ± 0.88 m · s - 2 and Goal Keeper; 6.75 ± 0.37 m · s - 2, remaining positions; 5.71 ± 0.14 m · s - 2). The positional profiles outlined in this study can assist skill and conditioning coaches to prescribe training sessions that will optimise the athlete's physical preparation for the demands of competition.

The relationship between performance of a single-leg squat and leap landing task: moving towards a netball-specific anterior cruciate ligament (ACL) injury risk screening method.

Field-based screening methods have a limited capacity to identify high-risk postures during netball-specific landings associated with anterior cruciate ligament (ACL) injuries. This study determined the biomechanical relationship between a single-leg squat and netball-specific leap landing, to examine the utility of including a single-leg squat within netball-specific ACL injury risk screening. Thirty-two female netballers performed single-leg squat and netball-specific leap landing tasks, during which three-dimensional (3D) kinematic/kinetic data were collected. One-dimensional statistical parametric mapping examined relationships between kinematics from the single-leg squat, and the 3D joint rotation and moment data from leap landings. Participants displaying reduced hip external rotation, reduced knee flexion, and greater knee abduction and knee internal rotation angles during the single-leg squat exhibited these same biomechanical characteristics during the leap landing (p < 0.001). Greater ankle dorsiflexion during the single-leg squat was associated with greater knee flexion during landing (p < 0.001). Ankle eversion during the single-leg squat was associated with frontal and transverse plane knee biomechanics during landing (p < 0.001). Biomechanics from the single-leg squat were associated with landing strategies linked to ACL loading or injury risk, and thus may be a useful movement screen for identifying netball players who exhibit biomechanical deficits during landing.

Change-of-Direction Biomechanics: Is What's Best for Anterior Cruciate Ligament Injury Prevention Also Best for Performance?

Change-of-direction maneuvers (e.g., side-step cutting) are an important aspect of performance in multi-directional sports, but these maneuvers are also associated with anterior cruciate ligament (ACL) injury. Despite this, the impact of biomechanics on ACL injury risk and performance is often examined in isolation. The purpose of this review was to examine the alignment between biomechanical recommendations for ACL injury prevention and performance with regard to change-of-direction maneuvers. Several studies linking change-of-direction biomechanics to both ACL injury risk and performance were examined. A degree of overlap was identified between biomechanical strategies that could both reduce ACL injury risk and enhance performance during change-of-direction maneuvers. A fore-foot footfall pattern along with trunk rotation and lateral flexion in the intended cutting direction were identified as biomechanical strategies that could both reduce potentially hazardous knee joint moments and enhance change-of-direction speed. Minimizing knee valgus during change-of-direction maneuvers may also reduce ACL injury risk, with this biomechanical strategy found to have no impact on performance. Certain biomechanical strategies proposed to reduce ACL injury risk were linked to reduced change-of-direction performance. A narrow foot placement and "soft" landings with greater knee flexion were identified as ACL injury prevention strategies that could have a negative impact on performance. The findings of this review emphasize the need to consider both ACL injury risk and performance when examining the biomechanics of change-of-direction maneuvers.

Exploring individual adaptations to an anterior cruciate ligament injury prevention programme.

BACKGROUND: Individual responses to anterior cruciate ligament injury prevention programmes (ACL IPPs) have received little attention. This study examined the effects of an ACL IPP on neuromuscular control and lower limb biomechanics during landing at the group and individual levels. METHODS: Sixteen female athletes were randomly allocated to training (n=8) or control (n=8) groups. Electromyography, and three-dimensional kinematic and kinetic data were collected during landing at two testing sessions. Repeated measures ANOVA and effect sizes (Cohen's d) examined the effect of the IPP at the group and individual levels. A sub-group analysis comparing the effect of the IPP on 'high-' (i.e. large peak knee abduction moment at baseline) versus 'low-risk' individuals was also conducted. RESULTS: At the group level; the IPP increased activation of the medial hamstrings prior to landing (p<0.001; d=0.264) and the medial gastrocnemius at landing (p<0.001; d=0.426), and increased hip external rotation early after initial contact (p<0.001; d=0.476). Variable adaptations were seen across individuals within the training group for all variables (p<0.001). The IPP had a large effect in reducing frontal plane knee moments for 'high-risk' individuals (d>0.91), however these results did not reach statistical significance (p>0.05). CONCLUSIONS: The IPP induced adaptations during landing, however, individual data revealed dissimilar responses to the programme. Individuals displaying a pre-existing high-risk strategy may incur greater benefits from IPPs, yet only if the programme targets the relevant high-risk strategy.

Simulating the effect of muscle weakness and contracture on neuromuscular control of normal gait in children.

Altered neural control of movement and musculoskeletal deficiencies are common in children with spastic cerebral palsy (SCP), with muscle weakness and contracture commonly experienced. Both neural and musculoskeletal deficiencies are likely to contribute to abnormal gait, such as equinus gait (toe-walking), in children with SCP. However, it is not known whether the musculoskeletal deficiencies prevent normal gait or if neural control could be altered to achieve normal gait. This study examined the effect of simulated muscle weakness and contracture of the major plantarflexor/dorsiflexor muscles on the neuromuscular requirements for achieving normal walking gait in children. Initial muscle-driven simulations of walking with normal musculoskeletal properties by typically developing children were undertaken. Additional simulations with altered musculoskeletal properties were then undertaken; with muscle weakness and contracture simulated by reducing the maximum isometric force and tendon slack length, respectively, of selected muscles. Muscle activations and forces required across all simulations were then compared via waveform analysis. Maintenance of normal gait appeared robust to muscle weakness in isolation, with increased activation of weakened muscles the major compensatory strategy. With muscle contracture, reduced activation of the plantarflexors was required across the mid-portion of stance suggesting a greater contribution from passive forces. Increased activation and force during swing was also required from the tibialis anterior to counteract the increased passive forces from the simulated dorsiflexor muscle contracture. Improvements in plantarflexor and dorsiflexor motor function and muscle strength, concomitant with reductions in plantarflexor muscle stiffness may target the deficits associated with SCP that limit normal gait.

A Systematic Evaluation of Field-Based Screening Methods for the Assessment of Anterior Cruciate Ligament (ACL) Injury Risk.

BACKGROUND: Laboratory-based measures provide an accurate method to identify risk factors for anterior cruciate ligament (ACL) injury; however, these methods are generally prohibitive to the wider community. Screening methods that can be completed in a field or clinical setting may be more applicable for wider community use. Examination of field-based screening methods for ACL injury risk can aid in identifying the most applicable method(s) for use in these settings. OBJECTIVE: The objective of this systematic review was to evaluate and compare field-based screening methods for ACL injury risk to determine their efficacy of use in wider community settings. DATA SOURCES: An electronic database search was conducted on the SPORTDiscus™, MEDLINE, AMED and CINAHL databases (January 1990-July 2015) using a combination of relevant keywords. A secondary search of the same databases, using relevant keywords from identified screening methods, was also undertaken. STUDY SELECTION: Studies identified as potentially relevant were independently examined by two reviewers for inclusion. Where consensus could not be reached, a third reviewer was consulted. Original research articles that examined screening methods for ACL injury risk that could be undertaken outside of a laboratory setting were included for review. STUDY APPRAISAL AND SYNTHESIS METHODS: Two reviewers independently assessed the quality of included studies. Included studies were categorized according to the screening method they examined. A description of each screening method, and data pertaining to the ability to prospectively identify ACL injuries, validity and reliability, recommendations for identifying 'at-risk' athletes, equipment and training required to complete screening, time taken to screen athletes, and applicability of the screening method across sports and athletes were extracted from relevant studies. RESULTS: Of 1077 citations from the initial search, a total of 25 articles were identified as potentially relevant, with 12 meeting all inclusion/exclusion criteria. From the secondary search, eight further studies met all criteria, resulting in 20 studies being included for review. Five ACL-screening methods-the Landing Error Scoring System (LESS), Clinic-Based Algorithm, Observational Screening of Dynamic Knee Valgus (OSDKV), 2D-Cam Method, and Tuck Jump Assessment-were identified. There was limited evidence supporting the use of field-based screening methods in predicting ACL injuries across a range of populations. Differences relating to the equipment and time required to complete screening methods were identified. LIMITATIONS: Only screening methods for ACL injury risk were included for review. Field-based screening methods developed for lower-limb injury risk in general may also incorporate, and be useful in, screening for ACL injury risk. CONCLUSIONS: Limited studies were available relating to the OSDKV and 2D-Cam Method. The LESS showed predictive validity in identifying ACL injuries, however only in a youth athlete population. The LESS also appears practical for community-wide use due to the minimal equipment and set-up/analysis time required. The Clinic-Based Algorithm may have predictive value for ACL injury risk as it identifies athletes who exhibit high frontal plane knee loads during a landing task, but requires extensive additional equipment and time, which may limit its application to wider community settings.

What is normal? Female lower limb kinematic profiles during athletic tasks used to examine anterior cruciate ligament injury risk: a systematic review.

BACKGROUND: It has been proposed that the performance of athletic tasks where normal motion is exceeded has the potential to damage the anterior cruciate ligament (ACL). Determining the expected or 'normal' kinematic profile of athletic tasks commonly used to assess ACL injury risk can provide an evidence base for the identification of abnormal or anomalous task performances in a laboratory setting. OBJECTIVE: The objective was to conduct a systematic review of studies examining lower limb kinematics of females during drop landing, drop vertical jump, and side-step cutting tasks, to determine 'normal' ranges for hip and knee joint kinematic variables. DATA SOURCES: An electronic database search was conducted on the SPORTDiscus(TM), MEDLINE, AMED and CINAHL (January 1980-August 2013) databases using a combination of relevant keywords. STUDY SELECTION: Studies identified as potentially relevant were independently examined by two reviewers for inclusion. Where consensus could not be reached, a third reviewer was consulted. Original research articles that examined three-dimensional hip and knee kinematics of female subjects during the athletic tasks of interest were included for review. Articles were excluded if subjects had a history of lower back or lower limb joint injury or isolated data from the female cohort could not be extracted. STUDY APPRAISAL AND SYNTHESIS METHODS: Two reviewers independently assessed the quality of included studies. Data on subject characteristics, the athletic task performed, and kinematic data were extracted from included studies. Studies were categorised according to the athletic task being examined and each study allocated a weight within categories based on the number of subjects assessed. Extracted data were used to calculate the weighted means and standard deviations for hip and knee kinematics (initial contact and peak values). 'Normal' motion was classified as the weighted mean plus/minus one standard deviation. RESULTS: Of 2,920 citations, a total of 159 articles were identified as potentially relevant, with 29 meeting all inclusion/exclusion criteria. Due to the limited number of studies available examining double-leg drop landings and single-leg drop vertical jumps, insufficient data was available to include these tasks in the review. Therefore, a total of 25 articles were included. From the included studies, 'normal' ranges were calculated for the kinematic variables of interest across the athletic tasks examined. LIMITATIONS: Joint forces and other additional elements play a role in ACL injuries, therefore, focusing solely on lower limb kinematics in classifying injury risk may not encapsulate all relevant factors. Insufficient data resulted in no normal ranges being calculated for double-leg drop land and single-leg drop vertical jump tasks. No included study examined hip internal/external rotation during single-leg drop landings, therefore ranges for this kinematic variable could not be determined. Variation in data between studies resulted in wide normal ranges being observed across certain kinematic variables. CONCLUSIONS: The ranges calculated in this review provide evidence-based values that can be used to identify abnormal or anomalous athletic task performances on a multi-planar scale. This may be useful in identifying neuromuscular factors or specific muscular recruitment strategies that contribute to ACL injury risk.

Neuromuscular dysfunction that may predict ACL injury risk: a case report.

This case report examined the neuromuscular function of a competitive female netball player six days prior to an incident where she sustained an acute anterior cruciate ligament injury during normal sports activity. Electromyography was used to examine activation onsets of four lower limb muscles (rectus femoris, biceps femoris, medial hamstrings and gluteus medius) relative to initial contact (IC) during netball-specific landings of varying complexity. The results of the injured participant were compared to the remaining participants in the study (n=8), and the injured participant's injured limb was compared to the contralateral limb. The injured participant was the only player to record delayed pre-injury muscle onsets after IC for all muscles tested in the injured limb, while her non-injured limb was comparable to the other participants tested. Furthermore, delayed muscle onset after IC occurred more frequently as landing complexity increased. This case report suggests that delayed muscle activity onset after IC during landing may be an important risk factor for ACL injury.