Assoc Prof Suzi Edwards

Background: The risk of concussion at the elite level of rugby league has been extensively evaluated. However, there has been very little concussion research conducted at the semi-elite level. Purpose: To examine cases of medically diagnosed concussion from a single season of adult men's semi-elite rugby league. Methods: A retrospective review of the 2019 Queensland Cup season head injury assessment surveillance program was completed. All Head Injury Assessment (HIA) cases, including cases of medically diagnosed concussion were retrospectively video reviewed and game play characteristic variables along with video signs of concussion were coded. This data was combined with the return to play data to form the research database. Results: There were 132 players removed for HIAs in 170 games. There were 36 players medically diagnosed with concussions, which equates to an incidence rate was 6.11 concussions per 1000 player match hours, or one concussion every 4.7 matches. All concussions occurred in a tackle event, where the player was struck in the head/face. Possible balance disturbance was the most commonly observed video sign (97.2 ¿%; 35/36), with slow to stand also commonly observed in concussed players (91.7 ¿%; 33/36). Most concussed players (63.9 ¿%; 23/36) did not miss a game following the concussion. Conclusion: This is one of the first studies to review video footage of concussions in sub-elite rugby league. These findings build on the growing body of video analysis research in rugby league and suggest that the retrospective review of the video of incidents may offer insights into modifiable risk factors that may help reduce concussion in rugby league.

Objectives: Hamstring strain injuries (HSIs) commonly affect the proximal biceps femoris long head (BFlh) musculotendinous junction. Biomechanical modeling suggests narrow proximal BFlh aponeuroses and large muscle-to-aponeurosis width ratios increase localized tissue strains and presumably risk of HSI. This study aimed to determine if BFlh muscle and proximal aponeurosis geometry differed between limbs with and without a history of HSI. Methods: Twenty-six recreationally active males with (n = 13) and without (n = 13) a history of unilateral HSI in the last 24 months underwent magnetic resonance imaging of both thighs. BFlh muscle and proximal aponeurosis cross-sectional areas, length, volume, and interface area between muscle and aponeurosis were extracted. Previously injured limbs were compared to uninjured contralateral and control limbs for discrete variables and ratios, and along the relative length of tissues using statistical parametric mapping. Results: Previously injured limbs displayed significantly smaller muscle-to-aponeurosis volume ratios (p = 0.029, Wilcoxon effect size (ES) = 0.43) and larger proximal BFlh aponeurosis volumes (p = 0.019, ES = 0.46) than control limbs with no history of HSI. No significant differences were found between previously injured and uninjured contralateral limbs for any outcome measure (p = 0.216¿1.000, ES = 0.01¿0.36). Conclusions: Aponeurosis geometry differed between limbs with and without a history of HSI. The significantly larger BFlh proximal aponeuroses and smaller muscle-to-aponeurosis volume ratios in previously injured limbs could alter the strain experienced in muscle adjacent to the musculotendinous junction during active lengthening. Future research is required to determine if geometric differences influence the risk of re-injury and whether they can be altered via targeted training.

Objective: The tackle is the most injurious event in rugby league and carries the greatest risk of concussion. This study aims to replicate previous research conducted in professional men's rugby league by examining the association between selected tackle characteristics and head impact events (HIEs) in women's professional rugby league. Methods: We reviewed and coded 83 tackles resulting in an HIE and every tackle (6,318 tackles) that did not result in an HIE for three seasons (2018¿2020) of the National Rugby League Women's (NRLW) competition. Tackle height, body position of the tackler and ball carrier, as well as the location of head contact with the other player's body were evaluated. Propensity of each situation that caused an HIE was calculated as HIEs per 1,000 tackles. Results: The propensity for tacklers to sustain an HIE was 6.60 per 1,000 tackles (95% CI: 4.87¿8.92), similar to that of the ball carrier (6.13 per 1,000 tackles, 95% CI: 4.48¿8.38). The greatest risk of an HIE to either the tackler or ball carrier occurred when head proximity was above the sternum (21.66 per 1,000 tackles, 95% CI: 16.55¿28.35). HIEs were most common following impacts between two heads (287.23 HIEs per 1,000 tackles, 95% CI: 196.98¿418.84). The lowest propensity for both tackler (2.65 per 1,000 tackles, 95% CI: 0.85¿8.20) and ball carrier HIEs (1.77 per 1,000 tackles, 95% CI: 0.44¿7.06) occurred when the head was in proximity to the opponent's shoulder and arm. No body position (upright, bent or unbalanced/off feet) was associated with an increased propensity of HIE to either tackler or ball carrier. Conclusions: In the NRLW competition, tacklers and ball carriers have a similar risk of sustaining an HIE during a tackle, differing from men's NRL players, where tacklers have a higher risk of HIEs. Further studies involving larger samples need to validate these findings. However, our results indicate that injury prevention initiatives in women's rugby league should focus on how the ball carrier engages in contact during the tackle as well as how the tackler executes the tackle.

Objectives: To investigate relationships between load tolerance of single leg isometric knee extension and athlete reported knee pain location and severity during the single leg decline squat. Design: Cross-sectional study. Methods: 175 college basketball athletes (99 women, 76 men) in Alberta, Canada participated at the start of the 2018¿19 season. Knee pain location (dichotomized into focal/diffuse pain), and severity (numerical rating scale 0¿10) were collected during the single leg decline squat. Athletes completed a standardized single leg isometric knee extension to determine load tolerance (defined by pain or reduced form). A quantile regression model was used to examine the association between load tolerance and pain location adjusting for sex, years played, body mass index and team. Results: Athletes with diffuse pain had a significantly lower median load tolerance (-0.89 kg) than athletes without pain (95% confidence interval [-1.49, -0.29]; p = 0.003). Athletes with focal pain tolerated similar median loads (-0.42 kg) to those without pain (95% confidence interval [-1.17, 0.33]; p = 0.26). Higher knee pain severity was associated with a non-linear but consistent reduction in load tolerance (p < 0.001). Conclusions: Athlete-reported knee pain location during the single leg decline squat influenced load tolerance to isometric knee extension. Athletes with focal pain tolerated similar isometric loads to their pain free teammates. Clinicians should consider load selection of isometric knee extension for athletes with diffuse pain given their lower load tolerance. Future research should consider reporting pain location in addition to pain severity to differentiate clinical presentations and response to exercise.

Background Movement competency screens (MCSs) are commonly used by coaches and clinicians to assess injury risk. However, there is conflicting evidence regarding MCS reliability. Purpose This study aimed to: (i) determine the inter-and intra-rater reliability of a sport specific field-based MCS in novice and expert raters using different viewing methods (single and multiple views); and (ii) ascertain whether there were familiarization effects from repeated exposure for either raters or participants. Study Design Descriptive laboratory study Methods Pre-elite youth athletes (n=51) were recruited and videotaped while performing a MCS comprising nine dynamic movements in three separate trials. Performances were rated three times with a minimal four-week wash out between testing sessions, each in randomized order by 12 raters (3 expert, 9 novice), using a three-point scale. Kappa score, percentage agreement and intra-class correlation were calculated for each movement individually and for the composite score. Results Fifty-one pre-elite youth athletes (15.0±1.6 years; n=33 athletics, n=10 BMX and n=8 surfing) were included in the study. Based on kappa score and percentage agreement, both inter-and intra-rater reliability were highly variable for individual movements but consistently high (>0.70) for the MCS composite score. The composite score did not increase with task familiarization by the athletes. Experts detected more movement errors than novices and both rating groups improved their detection of errors with repeated viewings of the same movement. Conclusions Irrespective of experience, raters demonstrated high variability in rating single movements, yet preliminary evidence suggests the MCS composite score could reliably assess movement competency. While athletes did not display a familiarization effect after performing the novel tasks within the MCS for the first time, raters showed improved error detection on repeated viewing of the same movement.

Background: Computer use is associated with poor postures and increased risk of developing neck pain. Evaluating differences in working posture of individuals with and without chronic neck pain may assist the development of strategies to lessen or prevent pain. Objective: To identify if upper body kinematics differs between individuals with and without chronic idiopathic neck pain during four conditions (tablet, laptop, and desktop computer sitting and standing). Methods: Three-dimensional (3D) motion capture measured upper body kinematics in 44 individuals with chronic idiopathic neck pain > 90 days (Cases n = 22) and without pain (Control n = 22), during a typing task under four conditions: tablet, laptop, desktop computer (sitting and standing). Differences between groups were evaluated using generalised linear mixed models. Results: Across all conditions and compared to controls, cases had significantly less flexion between their head-neck and upper trunk segments (between group mean difference 7.15°, 2.1, 12.2, p = .006), greater upper trunk flexion relative to the laboratory (-6.15°, -10.9, -1.3, p = .012), greater shoulder flexion bilaterally (left 12.35°, 6.7, 17.9, p < .001; right 13.49°, 7.9, 19.1, p < .001) and less right elbow flexion (-6.87°, -12.1, -1.7, p = .010). Approaching significance, the case group had less left elbow flexion (between group mean difference -5.36°, -10.9, 0.1, p = .056) and a smaller mean craniocervical angle for the seated desktop condition (group x condition interaction -6.37°; 95% CI -12.7, -0.1, p = .052). Significance: Individuals with neck pain consistently used different upper body postures compared to individuals without pain when working on computerised devices under varying workstation conditions. This finding suggests that people with neck pain work in potentially aggravating postures that may be associated with their pain.

Background: Few studies comprehensively analyse 3D neck kinematics in individuals with chronic idiopathic neck pain during functional tasks considered challenging. This critical knowledge is needed to assist clinicians to recognise and address how altered movement strategies might contribute to pain. Research question: Are there differences in 3D neck kinematics (angles, timing, velocity) during functional tasks in people with chronic neck pain compared to matched asymptomatic control participants? Methods: Participants with chronic idiopathic neck pain (n = 33) and matched asymptomatic controls (n = 30) performed four functional tasks (overhead reach forward, right and left, and putting on a seatbelt) while evaluated using 3D motion capture. Kinematic variables included joint angles, range of motion (ROM,°), velocity (m s-1) and timing (% of movement phase) for joint angles (head-neck [HN joint], head+neck-upper trunk [HNT], and thoracolumbar) and segments (head, neck, head+neck [HN segment], upper trunk, and trunk. Generalised linear mixed models examined between-group differences. Results: There were few between-group differences. The neck pain group had less HN segment extension that controls (mean difference [MD] left -2.06°; 95% CI -3.82, -0.29; p = .023; and right reach -2.52°; -4.67, -0.37; P = .022), and had less total sagittal HNT ROM across all tasks (-1.28; 95% CI -2.25, -0.31; p = .010). Approaching significance was the pain group having less thoracolumbar left rotation than controls (MD -2.14, 95% CI -4.41 to 0.13, p = .064). The pain group had higher neck segment peak flexion velocity than controls across all tasks (MD -3.09; 95% CI -5.21 to -0.10; P = .004). Timing of joint angle peaks did not differ between groups. Significance: When performing an overhead reach task to the left and right and putting on a seatbelt, people with neck pain maintain a more flexed HN segment, use less sagittal ROM and have higher velocity peaks. These findings can assist clinicians in their assessment of patients by identifying possible underlying contributors to neck pain.

The majority of musculoskeletal modelling studies investigating healthy populations use generic models linearly scaled to roughly match an individual's anthropometry. Generic models disregard the considerable variation in musculoskeletal geometry and tissue properties between individuals. This study investigated the physiological implications of personalizing musculoskeletal model geometry (body segment mass, inertia, joint center, and maximum isometric muscle force). Nine healthy athletes performed ten repetitions of 15 meter sprints at 75¿95% of their maximum sprinting speed and ten repetitions of unanticipated sidestep cut trials with a 4.5¿5.5 m/s approach running speed. Structural magnetic resonance imaging was collected on the lower extremities, from which subject-specific musculoskeletal models were developed. A one-dimensional statistical parametric mapping paired t-test was used to compare generic and subject-specific musculoskeletal models for: lower-limb kinematics, kinetics, torque matching, as well as hamstrings, adductors, and quadriceps muscle activations and fiber dynamics. Percentage change of geometric parameters between generic and subject-specific models were determined. Compared to generic models, subject-specific models showed significantly lower ankle dorsi/plantar flexion angle during sprinting and several significantly different net joint moments during sprint and cut tasks. Additionally, subject-specific models demonstrated better torque matching, more physiologically plausible fiber lengths, higher fiber velocities, lower muscle forces, and lower simulated activations in a subset of investigated muscles and motor tasks. Furthermore, subject-specific models identified between-limb differences that were not identified with generic models. Use of subject-specific modeling, even in healthy populations, may result in more physiologically plausible muscle fiber mechanics. Implementing subject-specific models may be especially beneficial when investigating populations with substantial geometric between-limb differences, or unilateral musculoskeletal pathologies, as these are not captured by a generic model.

The tackle is the in-game activity with the greatest risk for injury in collision sports. Qualitative match analysis has associated injury risk with tackle technique (e.g. tackle height, head position before contact). This exploratory study used gold-standard three-dimensional (3D) motion capture to investigate whether prior instructions to a tackler to execute different torso tackle types altered their tackle technique. Fifteen amateur-level rugby code players performed four sets of 10 tackle trials after instructions from an expert coach: two Australian National Rugby League (NRL) coaching manual instructions on upper and lower torso tackle height (UpperNRL, LowerNRL); and two novel variants that altered the tackler's contact with the ball carrier's upper torso (UpperPop) via a vertical 'pop action', or mid-torso (MidTorso) via increasing the contact height to the mid-torso. 3 D motion capture confirmed a favourable 'head up and forward' gaze focus on ball carrier before contact and a 'straight back' posture was more evident in UpperPop instruction than other instructions, with the least flexion for the head, trunk, trunk-pelvis, thoracolumbar and lumbopelvic (p < 0.01). MidTorso also attained a more optimal 'head up and forward' and a 'straight back' posture than a LowerNRL (p < 0.001). 'Leg drive on contact' revealed ankle, hip (p < 0.01) and thigh angles (p < 0.05) differences, likely to reflect the UpperPop 'pop action' instruction than other instructions. For coaches, this study demonstrated that amateur-level rugby-code players could follow instruction from an expert coach to execute tackling techniques within a session. Inclusion of tackle specific coaching instruction training program may be a viable injury reduction strategy.

BACKGROUND: Non-neutral postures during computerised device use coupled with increased usage may increase the risk of neck pain. Greater knowledge of postures that individuals with neck pain adopt during computerised device use is warranted. OBJECTIVE: To evaluate neck and upper limb posture while using a tablet, laptop and desktop computer (sitting and standing) in individuals with chronic neck pain. METHODS: Differences in three-dimensional kinematic variables were assessed during four conditions: tablet, laptop, desktop computer (sitting and standing) in 22 individuals with chronic neck pain >3 months. Differences between kinematic variables were determined using one-way repeated measures ANOVA with Bonferroni post-hoc tests. RESULTS: Compared to the desktop (sitting), tablet and laptop use resulted in increased neck flexion (mean difference tablet - 14.42°, 95% CI - 19.88, -8.96, P¿<¿0.001; laptop -7.19°, -12.08, -2.31, P¿=¿.020); upper trunk flexion (tablet -14.89°, -20.22, -9.56, P¿<¿0.001; laptop -5.56°, -10.02, -1.09, P¿=¿.009) and tablet bilateral shoulder elevation (left 11.01¿mm, 2.01, 20.04, P¿<¿.016; right 13.08¿mm, 3.09, 23.11, P¿<¿.006). CONCLUSIONS: Tablet and laptop use resulted in greater neck flexion, bilateral shoulder elevation and upper trunk flexion compared to a standard desktop computer, suggesting individuals with chronic neck pain should be mindful of their posture when using these smaller devices. Future research should explore how differences in posture may influence neck pain.

Background: Wearable inertial sensor technology (WIST) systems provide feedback, aim-ing to modify aberrant postures and movements. The literature on the effects of feedback from WIST during work or work-related activities has not been previously summarised. This review examines the effectiveness of feedback on upper body kinematics during work or work-related activities, along with the wearability and a quantification of the kinematics of the related device. Methods: The Cinahl, Cochrane, Embase, Medline, Scopus, Sportdiscus and Google Scholar databases were searched, including reportsfrom January 2005 to July 2021. The included studies were summarised descriptively and the evidence was assessed. Results: Fourteen included studies demonstrated a 'limited' level of evidence supporting posture and/or movement behaviour improvements using WIST feedback, with no improvements in pain. One study assessed wearability and another two investigated comfort. Studies used tri-axial accelerometers or IMU integration (n = 5 studies). Visual and/or vibrotactile feedback was mostly used. Most studies had a risk of bias, lacked detail for methodological reproducibility and displayed inconsistent reporting of sensor technology, with validation provided only in one study. Thus, we have proposed a minimum 'Technology and Design Checklist' for reporting. Conclusions: Our findings suggest that WIST may improve posture, though not pain; however, the quality of the studies limits the strength of this conclusion. Weara-bility evaluations are needed for the translation of WIST outcomes. Minimum reporting standards for WIST should be followed to ensure methodological reproducibility. Précis: This review summa-rises studies reporting on feedback from wearable inertial sensor technology (WIST) devices that aim to improve posture and/or movement behaviour during workplace-related tasks. The included studies lacked methodological reproducibility; therefore, a 'Technology and Design Checklist' was proposed. A 'limited' level of evidence supported changes in posture/movement behaviour using WIST, with no improvements in pain, though the study quality limits the strength of these findings.

Objectives: To identify if basketball players aged <20 years (U20) self-report hip and/or groin pain and if they perceive this as a problem. To determine potential differences in self-reported playing (training and match play) loads and Copenhagen Hip and Groin Outcome Score (HAGOS) between those with and without hip/groin pain. Design: Cross-sectional. Methods: Fifty-one pre-elite (state/national representative level) male U20 basketball players (Australian n = 38; Italian n = 13) self-reported current/historical hip/groin 'discomfort/pain' and 'problems', and playing loads. A two-factor regression model was fitted including main effects for hip/groin pain and Cohort and their interaction, with outcome variables playing loads and HAGOS subscale scores and dependent variable hip/groin pain. Results: Twenty-one players (41%) self-reported hip/groin 'discomfort/pain', of which nine perceived no 'problems'. Two of these nine players reported training/playing time loss due to pain. Those self-reporting hip/groin discomfort/pain scored lower than those without in HAGOS subscales Symptoms (mean difference in score 8.94; 95%CI -25.24, -5.97), Pain (5.00; -16.42, -2.81), Function in daily living (0.00; -26.72 to -5.59), Function in sport and recreation (6.25; -21.24, -5.33), and hip and/or groin Quality of Life (5.00; -28.63, -8.10), indicating worse hip/groin problems. Participation subscale scores were different only for Italian players (36.25; -51.25, -20.00), with players self-reporting hip/groin discomfort/pain scoring lower. Conclusion: Most players who perceive both hip/groin 'discomfort/pain' and 'problems' also report training/playing time loss, suggesting players' perceptions of problematic symptoms and time-loss are associated. Adolescent basketball players perceive hip/groin pain to negatively impact their daily lives and sporting function.

Background: Exposure to thousands of head and body impacts during a career in contact and collision sports may contribute to current or later life issues related to brain health. Wearable technology enables the measurement of impact exposure. The validation of impact detection is required for accurate exposure monitoring. In this study, we present a method of automatic identification (classification) of head and body impacts using an instrumented mouthguard, video-verified impacts, and machine-learning algorithms. Methods: Time series data were collected via the Nexus A9 mouthguard from 60 elite level men (mean age = 26.33; SD = 3.79) and four women (mean age = 25.50; SD = 5.91) from the Australian Rules Football players from eight clubs, participating in 119 games during the 2020 season. Ground truth data labeling on the captures used in this machine learning study was performed through the analysis of game footage by two expert video reviewers using SportCode and Catapult Vision. The visual labeling process occurred independently of the mouthguard time series data. True positive captures (captures where the reviewer directly observed contact between the mouthguard wearer and another player, the ball, or the ground) were defined as hits. Spectral and convolutional kernel based features were extracted from time series data. Performances of untuned classification algorithms from scikit-learn in addition to XGBoost were assessed to select the best performing baseline method for tuning. Results: Based on performance, XGBoost was selected as the classifier algorithm for tuning. A total of 13,712 video verified captures were collected and used to train and validate the classifier. True positive detection ranged from 94.67% in the Test set to 100% in the hold out set. True negatives ranged from 95.65 to 96.83% in the test and rest sets, respectively. Discussion and conclusion: This study suggests the potential for high performing impact classification models to be used for Australian Rules Football and highlights the importance of frequencies <150 Hz for the identification of these impacts.

Objective: The purpose of this study was to determine if there is a relationship between pain and movement kinematics during functional tasks, evaluated over time, in individuals with chronic idiopathic neck pain. Methods: Ten participants with chronic idiopathic neck pain performed 2 functional tasks (overhead reach to the right and putting on a seatbelt) while evaluated using 8 Oqus 300+ cameras. Kinematic variables included joint angles and range of motion (ROM) (°), head segment relative to neck segment (head-neck [HN]); and head/neck segment relative to upper thoracic segment (head/neck-trunk), velocity (m/s), and time (% of movement phase). Pain was quantified using a 100-mm visual analog scale. Linear mixed effects regression models were used to analyze associations between pain and kinematic variables adjusting for treatment group. Results: For overhead reach, higher pain was associated with less HN peak rotation at baseline (ß = ¿0.33; 95% CI -0.52 to ¿0.14, P = .003) and less HN total rotation ROM at 6 months (ß = ¿0.19; 95% CI ¿0.38 to ¿0.003, P = .048). For the seatbelt task, higher pain was associated with less HN peak rotation (ß = ¿0.52; 95% CI -0.74 to ¿0.30 to ¿0.74, P < .001) and less HN total rotation ROM at baseline (ß = ¿0.32; 95% CI ¿0.53 to ¿0.10, P = .006). No other movement variables demonstrated meaningful relationships with pain for the reach or seatbelt tasks. Conclusion: Higher pain is associated with less HN peak and total rotation during functional reaching tasks requiring head rotation. Recognizing altered functional kinematics in individuals with chronic neck pain may assist patient management.

PURPOSE: Patellar tendon abnormality (PTA) on diagnostic imaging is part of the diagnostic criteria for patellar tendinopathy. PTA and altered landing strategies are primary risk factors that increase the likelihood of asymptomatic athletes developing patellar tendinopathy. Therefore, the aim of this study was to examine the risk factors that are predictors of the presence and severity of a PTA in junior pre-elite athletes. METHODS: Ten junior pre-elite male basketball athletes with a PTA were matched with 10 athletes with normal patellar tendons. Participants had patellar tendon morphology, Victorian Institute of Sport Assessment (VISA) score, body composition, lower limb flexibility, and maximum vertical jump height measured before performing five successful stop-jump tasks. During each stop-jump task, both two-dimensional and three-dimensional kinematics and ground reaction forces were recorded. Multiple regression analyses were used to identify factors for estimating PTA presence and severity, and discriminate analysis was used to classify PTA presence. RESULTS: Sixty-eight percent of variance for presence of a PTA was accounted for by hip joint range of motion (ROM) and knee joint angle at initial foot-ground contact (IC) during stop-jump task and quadriceps flexibility, whereas hip joint ROM during stop-jump task and VISA score accounted for 62% of variance for PTA severity. Prediction of the presence of a PTA was achieved with 95% accuracy and 95% cross-validation. CONCLUSIONS: An easily implemented, reliable, and valid movement screening tool composed of three criteria enables coaches and/or clinicians to predict the presence and severity of a PTA in asymptomatic athletes. This enables identification of asymptomatic athletes at higher risk of developing patellar tendinopathy, which allows the development of effective preventative measures to aid in the reduction of patellar tendinopathy injury prevalence. Copyright © 2013 by the American College of Sports Medicine.

Purpose: Risk factors associated with a clinical presentation of patellar tendinopathy are patellar tendon ultrasonographic abnormality (PTA) and excessive loading. It remains unknown whether characteristics of an athlete's landing technique contribute to this excessive patellar tendon loading. This study investigated whether asymptomatic athletes with and without PTA had different landing strategies and hypothesized that asymptomatic athletes with a PTA would create higher patellar tendon loading and a different lower-limb landing strategy compared with athletes with normal patellar tendons. Methods: Seven athletes with no previous history or clinical signs of patellar tendon injury with a PTA were matched to athletes with normal patellar tendons (controls). Participants performed five successful trials of a stop-jump task, which involved a simultaneous two-foot horizontal and then vertical landing. During each trial, the participants' ground reaction forces and lower-limb electromyographic data were recorded, the three-dimensional kinematics measured, and the peak patellar tendon force calculated by dividing the net knee joint moment by the patellar tendon moment arm. Results: Significant between-group differences in landing technique were mostly observed during the horizontal landing phase. Participants with a PTA created similar patellar tendon loading to the controls, but with altered sequencing, by landing with significantly greater knee flexion and extending their hips while the controls flexed their hips as they landed, reflecting a different muscle recruitment order compared with the PTA group. Conclusions: The crucial part in the development of PTA and, in turn, patellar tendinopathy may not be the magnitude of the patellar tendon load but rather the loading patterns. This research provides clinicians with important landing assessment criteria against which to identify athletes at risk of developing patellar tendinopathy. Copyright © 2010 by the American College of Sports Medicine.

This study aimed to determine whether the landing phase of a drop landing (DL) differed with respect to a complete jumping and landing task, a spike jump (SJ), and whether fatigue altered the landing of these movements. Fourteen male volleyball players performed five DL and SJ in a counterbalanced order under two experimental conditions: non-fatigued and fatigued. Fatigue, induced by repetitive jumping sets, was confirmed by decrements in vertical jump height >25% and increased blood lactate >6 mmol/L. Each landing task was characterized by the resultant ground reaction forces (GRF), sagittal plane kinematics and muscle recruitment patterns of six lower extremity muscles. Two-way repeated analysis of variance results indicated a main effect of movement on many of the GRF, kinematic and electromyographic variables characterizing landing, indicating that the two tasks required substantially different lower limb biomechanics during landing. Although fatigue did not alter the GRF in either task, there were significant movement × fatigue condition interactions. The significant between-task differences in the biomechanical variables characterizing landing and the differential effects of fatigue on each landing task, question the validity of using a DL as an experimental task to investigate lower limb landing mechanics of whole jumping and landing movements. © 2009 John Wiley & Sons A/S.