Differences in Bone Mineral Density and Associated Factors in Dancers and Other Female Athletes.

Dancers are susceptible to Relative Energy Deficiency in Sport (REDs), specifically low total body areal bone mineral density (aBMD). Little is known about how dancers' BMD compares to other athletic populations. The objective of this study was to examine the association between participant characteristics and aBMD among female pre-professional dancers compared to other female athletes. 269 females [132 dancers [17.6 (3.2) years] and 137 sport participants [22.8 (2.6) years] were included in this study. aBMD (g/cm2) was estimated using dual X-ray absorptiometry. Multivariable linear regression was used to examine the association between height adjusted z-scores of aBMD (aBMD-Z) and age (years), body mass index (BMI) (z-score), supplement intake, history of stress fracture, irregular menses, MRI/bone scan, one-year injury history, oral contraceptives, and activity (dance/sport). Total body aBMD and aBMD-Z were lower in dancers than athletes [dancers: aBMD=1.03 g/cm2 (95% CI: 1.01, 1.05); aBMD-Z=-0.28 (-0.43, -0.12)(p<0.001); athletes: aBMD=1.14 g/cm2 (95% CI: 1.12, 1.16); aBMD-Z= 0.41 (0.25, 0.57) (p<0.001)]. aBMD-Z increased with age (ß=0.054, 95% CI: 0.017, 0.092; p=0.004) and BMI (ß=0.221, 95% CI: 0.006, 0.415; p=0.043). Activity type modified the relationship between BMI and aBMD-Z (ß=0.323, 95% CI: 0.025, 0.621; p<0.033) with a stronger positive association in dancers, compared to other female athletes. Dancers had lower total body aBMD and aBMD-Z than other female athletes. aBMD-Z increases with age in both groups. A stronger association exists between aBMD-Z and BMI in dancers than athletes. Future studies should consider changes in aBMD-Z during adolescence and associations with increased risk of bone injury.

Differences in Situational Patterns During Change of Direction Movements Greater than 90° in Youth Male and Female Soccer Players.

Change of direction (COD) maneuvers in soccer create tactical advantages, but also expose the player to an increased risk of injury. COD ability is commonly tested with pre-planned drills including cuts greater than 90°. These tests do not take into consideration positional differences players encounter during games. This case-series study used principal component analysis (PCA) to examine situational differences during COD movements between playing positions in youth soccer games. For each of the four teams included (26 females, 27 males), one game was analyzed using video-analysis. Two independent reviewers identified situational patterns and a PCA was used to examine differences between playing positions. Three principal components explained 89% of the variation in the data and were categorized as the total quantity of CODs, attacking/goal-scoring and defensive reacting types of CODs. One-way ANOVA on the individual principal component (PC) scores showed significant differences (p < 0.05) between centre midfielders, goalkeepers, and centrebacks in the quantity of CODs (PC1), and between wingers and fullbacks and centre backs in attacking/goal-scoring CODs (PC2), whereas PC3 was not different between playing positions. Differences between playing positions suggest that training and testing protocols in soccer could be enhanced to better match the individual and playing position-based needs.

Relationships Between Common Preseason Screening Measures and Dance-Related Injuries in Preprofessional Ballet Dancers.

OBJECTIVE: To examine modifiable and nonmodifiable factors for associations with dance-related injury among preprofessional ballet dancers over 5 academic years. DESIGN: Prospective cohort study. METHODS: Full-time preprofessional ballet dancers (n = 452; 399 female; median age [range], 15 years [11-21]) participated across 5 academic years at a vocational school. Participants completed baseline screening and online weekly injury questionnaires including dance exposure (hours/week). Zero-inflated Poisson regression models were used to examine associations between potential risk factors measured at baseline and self-reported dance-related injury. RESULTS: In count model coefficients, left one leg standing score (log coefficient estimate, -0.249 [95% CI: -0.478, -0.02]; P = .033) and right unipedal dynamic balance time (log coefficient estimate, -0.0294 [95% CI: -0.048, -0.01]; P>.001) carried a protective effect with increased years of training when adjusted for Athletic Coping Skills Inventory (ACSI) score. A significant association was found for left unipedal dynamic balance time and dance-related injury (log coefficient estimate, 0.013 [95% CI: 0.000, 0.026]; P = .045) when adjusted for years of training and ACSI score. There were no significant associations between dance-related injury and ankle and hip range of motion, active straight leg raise, or Y Balance Test measures. CONCLUSION: When adjusted for years of previous dance training and psychological coping skills, there was a significant association between limb-specific lumbopelvic control and dynamic balance tasks, as well as self-reported dance-related injury in preprofessional ballet. J Orthop Sports Phys Ther 2023;53(11):703-711. Epub 3 October 2023. doi:10.2519/jospt.2023.11835.

Pre-Season Screening Assessments: Normative Data for Pre-Professional Ballet Dancers.

OBJECTIVES: Pre-professional dance is high-risk, with injury incidence up to 4.7 injuries/1000 dance hours. Pre-season screening measures have been utilized to assess risk factors for dance-related injury, however normative values haven't been established for a pre-professional ballet population. The purpose of this study was to establish normative values of ankle and hip joint range of motion (ROM), lumbopelvic control, and dynamic balance pre-season screening measures for pre-professional ballet dancers. METHODS: 498 adolescent pre-professional ballet dancers [n = 219 junior division (194 female, 25 male; mean age: 12.9±0.9 year); n = 281 senior division (238 female, 41 male; mean age: 16.8±1.5 year)] participated in baseline screening tests across 5 seasons (2015-2019). Baseline measures took place at the beginning of each academic year: ankle ROM [dorsiflexion (deg); plantarflexion (PF) (deg)], total active turnout (TAT) (deg), lumbopelvic control [active straight leg raise (ASLR) (score); one leg standing test (OLS) (score)], and dynamic balance [unipedal balance (sec); Y-Balance Test (cm)]. RESULTS: Percentiles for ankle dorsiflexion ranged from 28.2° (male senior division, 10th percentile) to 63.3° (female junior division, 100th percentile). For PF, percentiles ranged from 77.5 to 111.8° (male junior division, 10th percentile; male senior division, 100th percentile). Percentiles for TAT for all participants ranged between 121.1° and 131.0°. For the ASLR, the proportion of participants moving with compensation (pelvis shifting) was between 64.0% and 82.2%. For OLS, 19.7% to 56.1% of dancers had a positive score (hip hiking). Percentiles for dynamic balance ranged from 3.5 to 17.1 seconds (unipedal dynamic balance) and 75.8 to 103.3 cm (YBT composite reach score) across all groups. CONCLUSION: The establishment of normative values of pre-season screening measures among a pre-professional ballet population can be used to determine areas to target during training, recognize individuals with possible injury risk, and inform return to dance protocols following injury. Comparison with other dancer/athletic populations will also provide insight into the performance of dancers and identify areas in need of improvement.

When should an athlete retire or discontinue participating in contact or collision sports following sport-related concussion? A systematic review.

OBJECTIVE: To systematically review the scientific literature regarding factors to consider when providing advice or guidance to athletes about retirement from contact or collision sport following sport-related concussion (SRC), and to define contraindications to children/adolescent athletes entering or continuing with contact or collision sports after SRC. DATA SOURCES: Medline, Embase, SPORTSDiscus, APA PsycINFO, CINAHL and Cochrane Central Register of Controlled Trials were searched systematically. STUDY ELIGIBILITY CRITERIA: Studies were included if they were (1) original research, (2) reported on SRC as the primary source of injury, (3) evaluated the history, clinical assessment and/or investigation of findings that may preclude participation in sport and (4) evaluated mood disturbance and/or neurocognitive deficits, evidence of structural brain injury or risk factors for increased risk of subsequent SRC or prolonged recovery. RESULTS: Of 4355 articles identified, 93 met the inclusion criteria. None of the included articles directly examined retirement and/or discontinuation from contact or collision sport. Included studies examined factors associated with increased risk of recurrent SRC or prolonged recovery following SRC. In general, these were low-quality cohort studies with heterogeneous results and moderate risk of bias. Higher number and/or severity of symptoms at presentation, sleep disturbance and symptom reproduction with Vestibular Ocular Motor Screen testing were associated with prolonged recovery and history of previous concussion was associated with a risk of further SRC. CONCLUSION: No evidence was identified to support the inclusion of any patient-specific, injury-specific or other factors (eg, imaging findings) as absolute indications for retirement or discontinued participation in contact or collision sport following SRC. PROSPERO REGISTRATION NUMBER: CRD42022155121.

Targeted interventions and their effect on recovery in children, adolescents and adults who have sustained a sport-related concussion: a systematic review.

OBJECTIVES: We evaluated interventions to facilitate recovery in children, adolescents and adults with a sport-related concussion (SRC). DESIGN: Systematic review including risk of bias (modified Scottish Intercollegiate Guidelines Network tool). DATA SOURCES: MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Embase, APA PsycINFO, Cochrane Central Register of Controlled Trials, CINAHL Plus with Full Text, SPORTDiscus and Scopus searched until March 2022. STUDY ELIGIBILITY CRITERIA: (1) Original research including randomised controlled trials (RCTs), quasi-experimental designs, cohort, comparative effectiveness studies; (2) focus on SRC; (3) English; (4) peer-reviewed and (5) evaluated treatment. RESULTS: 6533 studies were screened, 154 full texts reviewed and 13 met inclusion (10 RCTs, 1 quasi-experimental and 2 cohort studies; 1 high-quality study, 7 acceptable and 5 at high risk of bias). Interventions, comparisons, timing and outcomes varied, precluding meta-analysis. For adolescents and adults with dizziness, neck pain and/or headaches >10 days following concussion, individualised cervicovestibular rehabilitation may decrease time to return to sport compared with rest followed by gradual exertion (HR 3.91 (95% CI 1.34 to 11.34)) and when compared with a subtherapeutic intervention (HR 2.91 (95% CI 1.01 to 8.43)). For adolescents with vestibular symptoms/impairments, vestibular rehabilitation may decrease time to medical clearance (vestibular rehab group 50.2 days (95% CI 39.9 to 60.4) compared with control 58.4 (95% CI 41.7 to 75.3) days). For adolescents with persisting symptoms >30 days, active rehabilitation and collaborative care may decrease symptoms. CONCLUSIONS: Cervicovestibular rehabilitation is recommended for adolescents and adults with dizziness, neck pain and/or headaches for >10 days. Vestibular rehabilitation (for adolescents with dizziness/vestibular impairments >5 days) and active rehabilitation and/or collaborative care (for adolescents with persisting symptoms >30 days) may be of benefit.

Amsterdam 2022 process: A summary of the methodology for the Amsterdam International Consensus on Concussion in Sport.

The purpose of this paper is to summarise the consensus methodology that was used to inform the International Consensus Statement on Concussion in Sport (Amsterdam 2022). Building on a Delphi process to inform the questions and outcomes from the 5th International Conference on Concussion in Sport, the Scientific Committee identified key questions, the answers to which would help encapsulate the current science in sport-related concussion and help guide clinical practice. Over 3½ years, delayed by 2 years due to the pandemic, author groups conducted systematic reviews on each selected topic. The 6th International Conference on Concussion in Sport was held in Amsterdam (27-30 October 2022) and consisted of 2 days of systematic review presentations, panel discussions, question and answer engagement with the 600 attendees, and abstract presentations. This was followed by a closed third day of consensus deliberations by an expert panel of 29 with observers in attendance. The fourth day, also closed, was dedicated to a workshop to discuss and refine the sports concussion tools (Concussion Recognition Tool 6 (CRT6), Sport Concussion Assessment Tool 6 (SCAT6), Child SCAT6, Sport Concussion Office Assessment Tool 6 (SCOAT6) and Child SCOAT6). We include a summary of recommendations for methodological improvements for future research that grew out of the systematic reviews.

Injury epidemiology in pre-professional ballet dancers: A 5-year prospective cohort study.

INTRODUCTION: Pre-professional ballet dancers are at high-risk for injury, with injury rates ranging from 1.4 to 4.7 injuries/1000 dance-hours. In dance injury epidemiology, multi-year studies are limited, and findings are inconsistent. Thus, the extent to which injury estimates range from year to year in a pre-professional ballet program is currently unknown. OBJECTIVE: The aim of this study was to establish the extent and characteristics of injuries in pre-professional adolescent ballet dancers across five academic training years. METHODS: 452 female and male pre-professional ballet dancers (median age, 15 years; range, 11-20 years) participated across five academic years at a vocational ballet school. Participants completed an online weekly injury questionnaire (OSTRC-Q) and self-reported dance hours questionnaire. RESULTS: Questionnaire response was 91.4%. Depending on the definition of injury, yearly injury prevalence ranged from 32.1% (145/452; time-loss) to 67.4% (305/452; all-complaints) across the 5 years. Yearly injury rates ranged from 0.76 (95%CI: 0.66, 0.86; time-loss) to 2.54 (95%CI: 2.37, 2.73; all-complaints) per 1000 dance-hours. The ankle was the most reported injury location (range: 16-33%). CONCLUSIONS: Injury prevalence and injury rate estimates remained high across five academic years in a pre-professional ballet population. Injury estimates were highest when an all-complaints definition was employed. LEVEL OF EVIDENCE: Therapy/Prevention, Aetiology/Harm, level 2b.

Injury Rates and Characteristics Associated with Participation in Organized Dance Education: A Systematic Review.

INTRODUCTION: Several studies and recent systematic reviews have investigated injury in dance settings and have largely focused on specific concert dance genres (i.e., ballet, contemporary) and elite levels (i.e., pre-professional, professional) of dance. Less is known about the health of those who participate in dance education settings, namely teachers and students from private dance studios. Given that these individuals constitute a large proportion of the dance community, greater clarity of risks in the dance training environment could benefit an underserved majority by informing the development of effective injury prevention strategies.
Objective: The primary objective was to describe injury rates and characteristics associated with participation in organized dance education settings.
Methods: Six electronic databases were searched to April 2021 (Medline, EMBASE, SportDiscus, CINAHL, SCOPUS, Cochrane). Selected studies met a priori inclusion criteria that required original data from dance teacher and student samples within formal dance education settings. All genres of dance were eligible. Studies were excluded if no injury outcomes or estimates of dance exposure were reported, if injuries occurred during rehearsal and performance, or if dance was used as a therapeutic intervention or exercise. Two reviewers independently assessed each paper for inclusion at abstract and full text screening stages. The quality of included studies was assessed using the Joanna Briggs Institute Level of Evidence tool.
Results: The initial database search identified 1,424 potentially relevant records, 26 were included and scored. Most studies (n = 22) focused on dance students only, three included only dance teachers, and one study included both. Among both dance students and teachers, the majority of injuries reported were overuse or chronic and involved the lower limb. For studies that reported injury rates (n = 14), estimates ranged from 0.8 to 4.7 injuries per 1,000 dance hours, 4.86 per 1,000 dancer-days, and 0.21 to 0.34 per 1,000 dance exposures.
Conclusions: Based on the current research, dance students and teachers experience a similar rate of injury to concert and professional dancers, and their injuries are most commonly overuse injuries involving the lower extremity. There have been few high-quality investigations of injury specific to the dance training environment. Therefore, consensus around the burden of injury in the dance education settings remains difficult. Future dance epidemiological investigations that examine the burden of injury among dance teachers and students, include operational injury and exposure definitions, and utilize prospective designs are warranted.

Optimal Load Magnitude and Placement for Peak Power Production in a Vertical Jump: A Segmental Contribution Analysis.

ABSTRACT: Bordelon, NM, Jones, DH, Sweeney, KM, Davis, DJ, Critchley, ML, Rochelle, LE, George, AC, and Dai, B. Optimal load magnitude and placement for peak power production in a vertical jump: A segmental contribution analysis. J Strength Cond Res 36(4): 911-919, 2022-Weighted jumps are widely used in power training, however, there are discrepancies regarding which loading optimizes peak jump power. The purpose was to quantify the effects of load magnitudes and placements on the force, velocity, and power production in a countermovement vertical jump. Sixteen male and 15 female subjects performed vertical jumps in 7 conditions: no external load, 10 and 20% dumbbell loads, 10 and 20% vest loads, and 10 and 20% barbell loads with load percentages relative to body weight. Arm swing was encouraged for all, but the barbell load conditions. Kinematics were collected to quantify the whole-body (the person and external loads) forces, velocities, and power as well as segments' contributions to the whole-body forces and velocities. Repeated-measure analyses of variance were performed followed by paired comparisons. Jump heights were the greatest for the no external load and 10% dumbbell conditions. The 10 and 20% dumbbell conditions demonstrated the greatest peak whole-body power, while the 2 barbell conditions showed the lowest peak whole-body power. At the time of peak whole-body power, the 2 dumbbell and 2 vest conditions resulted in greater whole-body forces. Whole-body velocities were the greatest for the no external load and 10% dumbbell conditions. Holding the dumbbells in the hands magnified the effects of external loads in producing forces and velocities. The constraint of arm movements in the barbell conditions limited power production. These findings highlight the importance of load placement and arm swing in identifying the optimal configuration for power production in weighted jumps.

Association between pre-participation characteristics and risk of injury amongst pre-professional dancers.

STUDY DESIGN: Prospective Cohort Study. BACKGROUND: Few investigations utilize evidence-informed pre-participation evaluation, inclusive injury definitions, and prospective surveillance to identify risk factors for dance-related injuries. OBJECTIVE: To evaluate pre-participation characteristics that may be associated with greater odds of dance-related musculoskeletal complaints in pre-professional dancers. METHODS: Full-time pre-professional ballet [n = 85, 77 females, median (range) age 15-years (11-19)] and contemporary [n = 60, 58 females, 19-years (17-30)] dancers underwent pre-participation evaluation: baseline questionnaire, coping skills, body mass index, bone mineral density, ankle range-of-motion, active standing turnout, lumbopelvic control, and balance tests. Self-reported complaints (any physical problem making dance participation difficult, irrespective of medical attention or time-loss) were captured weekly via online questionnaires for one academic year. Self-reported musculoskeletal complaints were recorded weekly (yes/no). Potential risk factors were identified a-priori through systematic review. Associations between potential risk factors and musculoskeletal complaints were examined with generalized linear mixed method regression models. RESULTS: Response rate was 99%, with 81% of dancers reporting at least one musculoskeletal complaint. Of 1521 complaints (19% first-time, 81% ongoing), the ankle (22%), knee (21%), and foot (12%) accounted for the majority. Injury history [odds ratio (OR) 7.37 (95% CI 3.41, 15.91)] and previous week's dance hours [OR 1.02 (1.01, 1.03)] were associated with dance-related musculoskeletal complaints. CONCLUSIONS: Prevalence of musculoskeletal complaints amongst pre-professional dancers is high and associated with injury history and training volume. Further understanding of the relationship between training load and injury is needed, with particular consideration of the dynamic and recursive nature of dance injury etiology. LEVEL OF EVIDENCE: Therapy / Prevention, Aetiology / Harm, level 2b.

The Effect of Stirrup Length on Impact Attenuation and Its Association With Muscle Strength.

ABSTRACT: Keener, MM, Critchley, ML, Layer, JS, Johnson, EC, Barrett, SF, and Dai, B. The effect of stirrup length on impact attenuation and its association with muscle strength. J Strength Cond Res 35(11): 3056-3062, 2021-Horseback-riders have a high prevalence of low back injuries, which may be related to the repetitive low back impacts experienced in riding. The purposes of this study were to quantify the effect of 3 stirrup lengths and 2 riding styles on the peak acceleration experienced by the rider and the association between the peak acceleration and the rider's different elements of muscle strength. Thirteen female riders performed a sitting or rising trot at each of the 3 stirrup lengths (2-point length, mid-seat length, or dressage length), while the acceleration of the tibia, sacrum, seventh cervical vertebra (C7), and head were collected. Subjects completed a push-up, a vertical jump, and 4 core exercises to assess upper-body strength, lower-body strength, and core endurance, respectively. Peak acceleration of the sacrum, C7, and head were generally lower in the standing phase of the rising trot compared with the sitting phase of either the sitting or rising trot, particularly at the shortest stirrup length. Peak acceleration of the sacrum, C7, and head decreased as the stirrup length was shortened in the standing phase of the rising trot. Canonical correlations showed nonsignificant correlations between strength measurements and peak acceleration. Riding with more weight supported through the legs with a short stirrup length may decrease low back impacts and their associated injury risk. Technique training is likely needed to encourage riders to use lower-body and core strength for impact attenuation.

Longitudinal assessments of balance and jump-landing performance before and after anterior cruciate ligament injuries in collegiate athletes.

The purpose was to quantify the effect of an anterior cruciate ligament (ACL) injury on balance and jump-landing performance and bilateral asymmetries. Among 500 collegiate athletes who performed a reaching test and a double-leg counter-movement jump-landing test at baseline, 8 male and 6 female athletes suffered ACL injuries. In the follow-up, they performed the reaching test 3 and 6 months after ACL reconstruction (ACLR) and the jump-landing test 6 months after ACLR. Less reaching distances for the injured leg and increased reaching distance asymmetries were observed 3 and 6 months after ACLR compared to baseline. Less peak jumping and landing forces for the injured leg and increased jumping and landing force asymmetries were found 6 months after ACLR compared to baseline. The decreased performance of the injured leg and increased asymmetries may contribute to the high ACL re-injury rates. Baseline assessments would be useful for establishing an individual's pre-injury performance.

Comparison of Center of Pressure and Kinematic Differences in Grand Plié With and Without the Barre.

The purpose of this study was to determine what differences exist when performing grand plié with and without the barre. Differences in center of pressure (COP) sway, trunk kinematics, and lower extremity kinematics were used in this analysis for both first (P1) and fifth positions (P5). It was hypothesized that use of the barre would result in decreased COP sway, but increased asymmetries in trunk and lower extremity kinematics would be seen compared with the same movements performed without the barre in both positions. Sixteen collegiate dancers (1 male, 15 female) performed three trials of grand plié in P1 and P5 (right leg crossed in front) with or without the barre, for a total of 12 trials. For the barre condition (BC), participants demonstrated less time to complete grand plié, slightly less depth in grand plié, and decreased anterior-posterior (AP) sway compared to the without barre condition (WBC). The BC condition showed increased peak left trunk rotation, right knee flexion, decreased right and left peak hip flexion, and increased right hip abduction in both P1 and P5. Comparing P1 to P5, there was decreased AP sway, decreased peak left trunk rotation, decreased peak right and left hip flexion, increased left hip abduction, and decreased right knee flexion in both BC and WBC conditions. For the BC, there was increased right hip abduction in P1 compared to P5. Our results indicate that while use of the barre provides proprioceptive information, which helps dancers to control balance and learn a motor control strategy, grand plié should also be taught without the barre to challenge the dancer's balance control with different movement patterns in space.

The effects of mid-flight whole-body and trunk rotation on landing mechanics: implications for anterior cruciate ligament injuries.

The purpose was to quantify the effects of mid-flight whole-body and trunk rotation on knee mechanics in a double-leg landing. Eighteen male and 20 female participants completed a jump-landing-jump task in five conditions: no rotation, testing leg ipsilateral or contralateral (WBRC) to the whole-body rotation direction, and testing leg ipsilateral (TRI) or contralateral to the trunk rotation direction. The WBRC and TRI conditions demonstrated decreased knee flexion and increased knee abduction angles at initial contact (2.6 > Cohen's dz > 0.3) and increased peak vertical ground reaction forces and knee adduction moments during the 100 ms after landing (1.7 > Cohen's dz > 0.3). The TRI condition also showed the greatest knee internal rotation angles at initial contact and peak knee abduction and internal rotation angles and peak knee extension moments during the 100 ms after landing (2.0 > Cohen's dz > 0.5). Whole-body rotation increased contralateral knee loading because of its primary role in decelerating medial-lateral velocities. Trunk rotation resulted in the greatest knee loading for the ipsilateral knee due to weight shifting and mechanical coupling between the trunk and lower extremities. These findings may help understand altered trunk motion in anterior cruciate ligament injuries.

Mid-flight trunk flexion and extension altered segment and lower extremity joint movements and subsequent landing mechanics.

OBJECTIVES: To assess the effect of mid-flight trunk flexion and extension on the movements of body segments and lower extremity joints and subsequent landing mechanics during a jump-landing task. DESIGN: Participants performed three jump-landing conditions in a randomized order. METHODS: Forty-one participants completed jump-landing trials when performing three different mid-flight trunk motion: reaching forward, reaching up, and reaching backward. Whole-body kinematic and ground reaction force data were collected. RESULTS: The reaching backward condition resulted in a more posteriorly positioned upper body center of mass (COM) and more anteriorly positioned pelvis COM, legs COM, hip, and knee joint positions relative to the whole-body COM in flight and at initial contact of landing. The reaching backward condition showed the least hip flexion and ankle plantarflexion angles at initial contact as well as the least hip and knee flexion angles and the greatest ankle dorsiflexion angles at 100ms after landing. The reaching backward condition also demonstrated the greatest peak posterior ground reaction forces, peak and average knee extension moments, peak and average hip flexion moments, and peak knee varus moments within the first 100ms after landing. Opposite changes were observed for the reaching forward condition. CONCLUSIONS: Mid-flight trunk extension resulted in body postures that predisposed individuals to land with increased knee extension and varus moments and decreased knee flexion angles, which are indirectly associated with increased ACL loading. These findings may help to understand altered trunk motion during certain ACL injury events and provide information for developing jump-landing training strategies.