Effect of Hip-Focused Injury Prevention Training for Anterior Cruciate Ligament Injury Reduction in Female Basketball Players: A 12-Year Prospective Intervention Study

Outcomes of a randomized controlled trial of neuromuscular training with real-time biofeedback in young female athletes

BACKGROUND

A large body of scientific work has been focused on reducing the high incidence rate of anterior cruciate ligament (ACL) injuries in young female compared to male soccer players. The purpose of this study was to determine the effects of a randomized clinical trial to reduce a risk factor of ACL injuries, knee abduction moment (KAM), with neuromuscular training and biomechanical biofeedback in adolescent female athletes.

METHODS

A prospective, randomized, active comparator, open blinded, end-point trial was conducted with 150 (age: 13.3 ± 2.2 yrs, height: 156.1 ± 1 0.6 cm, mass: 50.2 ± 11.3 kg) female soccer players. Each participant received neuromuscular training and randomized into one of three arms: 1) an active control, considered sham biofeedback (NMT), 2) a knee-focused biofeedback group (NMT + K), and 3) a hip-focused biofeedback group (NMT + H). The participants completed two assessments: a baseline session prior to the intervention and a post-intervention session. The primary outcome measure was change knee abduction moment during a double leg drop vertical jump (DVJ). Additionally, an unplanned single leg cutting task was also recorded. As an exploratory outcome measure, athletic exposures and ACL injuries were recorded weekly for six months following the post-test session.

RESULTS

A statistically significant reduction in KAM, during the DVJ, was found in all three intervention groups from baseline to the post-test (p < 0.05). However, statistically significant improvements in KAM during cutting was only observed in the NMT + H intervention group (p < 0.05). ACL injuries were not reported in any intervention group during the six months of follow up.

CONCLUSIONS

While female soccer players involved in neuromuscular training programs regardless of intervention group exhibit significant improvements in KAM during a double leg landing, those that engage in hip-focused biofeedback compared to knee-focused or sham biofeedback exhibit decreased KAM during an unanticipated cutting maneuver.

TRIAL REGISTRATION

The Institutional Review Board at High Point University approved the study protocol. The clinical trial was registered at Clinicaltrials.gov (Identifier: NCT02754700) on 28/04/2016..

Targeting the hip and/or knee extensors during the back squat in males and females: A repeated measures decision tree analysis using the relative difference in trunk and tibia inclination and knee flexion angle

OBJECTIVE

To determine what combination of relative trunk and tibia inclination and knee flexion biases the hip and knee extensors during the squat.

DESIGN

Repeated measures.

SETTING

University research laboratory.

PARTICIPANTS

16 healthy individuals.

MAIN OUTCOME MEASURES

The average hip/knee extensor moment ratio (HKR) was calculated during squat descent, and trunk-tibia inclination difference and knee flexion angle at peak knee flexion. A regression tree for repeated measures determined what combination of trunk-tibia inclination difference and knee flexion angle predicted HKR.

RESULTS

HKR was predicted by trunk-tibia inclination difference (primary predictor) and knee flexion (secondary predictor). Four squatting strategies emerged: knee extensor bias (average HKR = 0.3), neutral bias (average HKR = 0.9), hip extensor bias (average HKR = 1.5), and high hip extensor bias (average HKR = 2.2). When trunk inclination exceeded tibia inclination ( ≥ 2.2°), hip-biased squatting was evident. Squat depth affected only hip-biased squatting: high hip extensor bias at moderate depths (<96° knee flexion), and a less pronounced hip bias at greater depths ( ≥ 96° knee flexion).

CONCLUSIONS

Our results provide a framework to bias the squat exercise based on intent. To maximize or minimize hip relative to knee extensor demands, clinicians should be cognizant of the trunk inclination relative to tibia inclination and the influence of knee flexion.

Therapeutic exercise protocol for the prevention of anterior cruciate ligament injuries in female soccer players with dynamic knee valgus (RCT)

BACKGROUND

Women's football has experienced exponential growth over the last 10 years. Its popularity is associated with an increase in ACL injuries. They constitute a major current problem as they account for 43% of the injury burden during the sports season. Despite the existing training programs, no uniform criteria have been established to design a precise intervention protocol, with specific tasks linked to women's football, nor has it been proposed to optimize the current programs.

METHODS

Randomized, double-blind, single-center clinical trial protocol scheduled for the 2025-2026 women's football season. There will be 2 groups: a group that will follow a specific ACL injury prevention protocol and a control group. The intervention period will last 12 weeks. Measurements will be taken at 3 time points. The biomechanics of the lower limbs, the jump-landing dynamics, and the pre- and post-training satisfaction of the players will be evaluated. Image capture and processing systems will be used as well as tests such as the DVJ and the LESS scoring system, among others.

DISCUSSION

This protocol aims to be one of the first to implement an ACL injury prevention program for women footballers with DKV. Despite the scarcity of research in this area, studies support beneficial effects at a preventive level.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06083818. Registered on 03 October 2023.

Perspectives on usability and adoption of a new ACL injury prevention programme for female handball players: a mixed methods approach

Effective injury prevention programmes (IPPs) hold promise for mitigating ACL injuries in female handball players, yet adherence remains a challenge. This mixed methods study explores the relationship between programme usability characteristics and the potential effectiveness of a newly developed ACL IPP through survey and interview data from 23 female handball players aged 15-18 and their four coaches. Players' knee abduction moment (KAM) was measured during a cutting task and used to measure potential effectiveness. Findings reveal significant correlations between reductions in KAM and players' perceived effectiveness of the programme in reducing ACL injury risk and their intention to use it (Spearman's rho (rs) -0.52, 95% CI -0.78 to -0.1, p=0.02 and rs -0.46, 95% CI -0.75 to -0.03, p=0.04, respectively). Coaches and players identified efficiency and perceived effectiveness as key factors influencing programme adoption. Concerns regarding programme length and doubts about exercise efficacy and transferability emerged as barriers, while perceived effectiveness, efficiency and enjoyability were facilitators for programme use. Players' suggestions for programme improvement included shortening the duration and incorporating playful elements. Design thinking sessions yielded strategies to optimise time efficiency and integrate IPPs into existing training routines. The study reaffirms the importance of balancing programme effectiveness with practicality and clear communication about its purpose and benefits to facilitate programme adoption. Enhancing programme usability and involving all end-users in the design process are crucial steps toward promoting the acceptance and adoption of IPPs among target populations.

Sport-specific differences in ACL injury, treatment and return to sports: Basketball

Basketball is an intense, fast-paced game that is physically, highly demanding. Certain aspects of the game, such as the quick pivoting and cutting movements, predispose the players to serious knee injuries, including anterior cruciate ligament (ACL) tears. While an ACL tear can be a devastating condition for players, multidisciplinary management of the injury can provide the players with a reasonable chance to return to play at the pre-injury level. This article aims to review the general principles and guidelines for the management of ACL injury in basketball players. The diagnosis, surgical treatment, rehabilitation and return to sports are discussed from European and North American perspectives. With a comprehensive and multidisciplinary approach to this condition, medical professionals can provide injured basketball players with a favourable prognosis for returning to play at the pre-injury level. To return to normal life and basketball after ACL reconstruction, the proposed approach includes (1) the selection of the appropriate surgical graft and technique, (2) maintaining a healthy and persistent mental state during rehabilitation, and (3) following a scientific rehabilitation programme based on personalized recovery. LEVEL OF EVIDENCE: Level V.

Effectiveness of Injury Prevention Program Using a Global Systems Approach on High-Risk Movement Mechanics for Noncontact ACL Injury

BACKGROUND

Injury prevention training using a global systems approach was designed to develop integrated trunk-lower extremity neuromuscular control using whole-body, rotational forces about the vertical Z-axis during simulated sports movements.

HYPOTHESIS

Compared with traditional hip-focused exercises, injury prevention training using a global systems approach could improve kinetic and kinematic measures related to anterior cruciate ligament injury.

STUDY DESIGN

Controlled laboratory study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 39 male and female athletes received 6 weeks of either global systems approach (n = 20), or hip-focused strengthening, balance, and plyometrics training (n = 19) exercises. Before and after the training program, participants performed a single-leg vertical drop jump task on their dominant leg. Peak vertical ground-reaction forces (GRFs), peak knee abduction, internal rotation moments, peak hip flexion, hip adduction, knee flexion, knee abduction, contralateral pelvic drop, and lateral trunk flexion angles were assessed. Biomechanical data were compared between the 2 groups using a random-intercept linear mixed-models analysis.

RESULTS

A significant group × time interaction effect was found for vertical GRFs (P = 0.01; change difference relative to baseline: 4.5%), knee abduction moment (P = 0.01; 14.8%), hip adduction (P < 0.01; 16.7%), knee abduction (P < 0.01; 13.8%), contralateral pelvic drop (P < 0.01; change difference: 26.6%), and lateral trunk flexion (P = 0.04; 20.37%) angles, favoring the global systems approach group after 6 weeks of training.

CONCLUSION

Participants who trained using the global systems approach had significantly decreased lateral trunk flexion, hip adduction, knee abduction and contralateral pelvic drop angles, peak vertical GRFs, and peak knee abduction moment during a single-leg vertical drop jump compared with participants who trained with hip-focused exercises.

CLINICAL RELEVANCE

Incorporating additional external resistance at the proximal trunk results in improved biomechanics compared with conventional hip-focused exercises.

Lower Extremity Strength Relative to Body Mass in Pediatric Female Athletes: Implications for Anterior Cruciate Ligament Injury

This study compared lower extremity (LE) muscular strength by 3 groups of female athletes using chronological age and consideration of age of peak height velocity (PHV). Isometric quadriceps, hamstrings, and hip abductors strength were assessed from physically active, pediatric females. The body mass normalized isometric strength (N m/kg) was compared by the 3 age groups. There were 388 young female athletes (<10 years [14.2%], 11-14 years [48.7%], and 15-18 years [37.1%]). The body mass normalized LE strength was lower in 11-14 years compared with <10 years (quadriceps [P = .001], hamstrings [P = .001], and hip abductors [P = .037]) as well as in 15-18 years relative to <10 years in quadriceps (P = .001) and hamstrings (P = .001). The analysis results were consistent with both chronological age alone and incorporating effects of age of PHV. In short, body mass normalized LE strength (quadriceps, hamstrings, and hip abductors) of 11-14 years females was lower than <10 years females.

Sure Steps: Key Strategies for Protecting Basketball Players from Injuries-A Systematic Review

Background: Basketball is a high-intensity sport, which includes actions such as jumping, changes of direction, accelerations, and decelerations, which generates fatigue situations that may increase the risk of injury. Specifically, the joints at greatest risk are the ankle and knee, with ankle sprains and anterior cruciate ligament (ACL) tears being the most prevalent injuries. There are several strategies aimed at reducing the incidence, based on training methods or other prophylactic measures. Therefore, the purpose of the study is to perform a systematic review of the different injury prevention strategies in competitive-level basketball players with respect to general injuries, ankle sprains, and ACL injuries. Methods: For this purpose, the PRISMA methodology was applied, performing a search in three databases (PubMed, SPORTDiscus, and Cochrane) between 25 September 2023 and 8 October 2023. Results: A total of 964 articles were identified, out of which 283 were duplicates and 644 were discarded. Out of the remaining 37, 23 were excluded because they did not meet the inclusion criteria; therefore, 14 articles were finally included. With respect to general injuries, 8 out of 14 studies reviewed them. Concerning ankle sprains, 7 studies specifically analyzed them. Finally, 3 studies focused on ACL injuries. Conclusions: Training programs that combine different contents, known as neuromuscular training, including strength work, stabilization or core, mobility, and agility are the most effective for both general injuries and ACL injuries. For ankle sprains, the most effective measures are training programs based on analytical ankle stability exercises and the use of ankle braces. Adherence to prevention programs is essential, so they can be included as part of the warm-up. Other strategies such as training load control, functional assessment, or rule modification are not used in the included articles, so their effectiveness as prophylactic methods could not be justified.

ACL Injury Prevention Education Improves Implementation of Neuromuscular Training Among High School Sports Coaches: A Cross-Sectional Survey Study

BACKGROUND

Neuromuscular training (NMT) programs delivered by trained personnel have demonstrated protective effects against anterior cruciate ligament (ACL) injury among high school sports participants, but few studies have investigated the impact of education on high school sports coaches' knowledge and incorporation of NMT programs into daily practice sessions.

PURPOSE

We sought to evaluate changes in knowledge and behavior among high school sports coaches who completed an NMT-based injury prevention training program.

METHODS

High school sports coaches were invited to complete a free online training course in incorporating NMT into daily practice sessions. Anonymized surveys were administered before and after education and at 3 months to evaluate knowledge level and program effectiveness.

RESULTS

Of the 13,640 coaches who enrolled in the training course in 2019, 1641 submitted pre- and post-education and 3-month follow-up surveys. Prior to training, 4.4% reported incorporating NMT into daily training sessions and the mean knowledge score was 1.89 ± 1.55. After training, 92.7% of participants reported that they intended to incorporate NMT into their daily training sessions and the mean knowledge score was 4.87 ± 1.11. At 3-month follow-up, 88.9% of participants reported incorporating NMT into daily training sessions. A chi-square test revealed a significant association between pre- and post-education incorporation of NMT into daily practice sessions, and a multiple regression analysis resulted in a significant model with intent to incorporate NMT into daily practice sessions identified as a significant behavior predictor.

CONCLUSION

These survey results show that completion of a training course significantly improved ACL injury prevention knowledge among a cohort of high school sports coaches and likely contributed to the sustained incorporation of NMT into their daily practice sessions.

Time course of biomechanics during jump landing before and after two different fatigue tasks

Objective

Muscle fatigue contributes to anterior cruciate ligament (ACL) injuries, with increased knee and hip abduction observed during fatigue. However, there have been no reports revealing the differences between fatigue tasks or the duration of these changes. In this study, we conducted single-leg drop landings before and after hip and knee fatigue tasks to elucidate the changes in lower limb biomechanics over time.

Methods

Twenty-two male participants performed single-leg drop landings before, immediately after, and 5, 10, and 15 min after fatigue tasks involving isokinetic hip abduction/adduction (hip fatigue task [HFT]) and knee extension/flexion (knee fatigue task [KFT]). Hip and knee kinematic and kinetic data were collected using a three-dimensional motion analysis device and two force plates. A two-way ANOVA was performed with both the fatigue task (HFT and KFT) and time point (Time 1 to Time 4) as factors, and the main effects and interactions were calculated.

Results

The knee adduction angle after the HFT was significantly greater than that after KFT immediately following the fatigue task. The knee flexion moment was significantly lower in the KFT, whereas the knee adduction and internal rotation moments were significantly higher in the HFT immediately after the fatigue task.

Conclusion

This study revealed distinct kinematic and kinetic changes specific to each fatigue task, particularly in the frontal plane for hip joint tasks and the sagittal plane for knee joint tasks. These findings could assist in the development of ACL injury prevention programs tailored to the functional improvement and exercise capacity of each joint.

Decreased moment of inertia of the lower limb facilitates a rapid hip internal rotation in a simulated foot impact maneuver. A laboratory-controlled biomechanical study for a precursor mechanism of noncontact anterior cruciate ligament injury

BACKGROUND

Anterior cruciate ligament injury frequently occurs in the deceleration with the knee-extended position. In addition, a rapid hip internal rotation is concomitantly observed. However, how the extended knee position induces the hip internal rotation is unclear.

METHODS

Sixteen healthy participants performed the simulated foot impact task on the experimental chair. To vary the knee flexion angle, the following four-foot placement positions relative to the pelvis segment, i.e.: 1) near; 2) middle; 3) far; and 4) far + heel strike, were tested. The reflective marker positions and the ground reaction force (GRF) data were collected. The moment of inertia of the entire lower limb around its long axis as well as the peak hip internal rotation angular velocity were calculated and compared among four conditions (Wilcoxon Signed-Rank Test with Bonferroni correction, P<0.0083).

RESULTS

As the knee extended from the near to far + heel strike condition, the moment of inertia of the entire lower limb significantly decreased and hip internal rotation angular velocity significantly increased (P<0.001).

CONCLUSIONS

The extended knee position with far foot placement from torso reduces the inertial resistance of the entire lower limb around its long axis and is vulnerable to the hip internal rotation.

Larger hip external rotation motion is associated with larger knee abduction and internal rotation motions during a drop vertical jump

Associations among hip motions, knee abduction and internal rotation motion during a drop vertical jump (DVJ), which increases the risk of anterior cruciate ligament injury, remain unclear. The purpose of this study was to examine associations among knee abduction, internal rotation and hip joint motions during a DVJ. Fifty-seven young female participants performed a DVJ from a 30-cm height. Hip and knee kinematics and kinetics were analysed using a three-dimensional motion analysis system and force plates. Multiple regression analysis showed that peak knee abduction angle was negatively associated with knee internal rotation and hip internal rotation excursions from initial contact (IC) to peak knee flexion, and positively associated with peak knee abduction moment (R2 = 0.465, P< 0.001). Peak knee internal rotation angle was negatively associated with the hip flexion excursion from IC to peak knee flexion and peak hip adduction moment (R2 = 0.194, P= 0.001). In addition, hip internal rotation excursion was negatively associated with knee abduction and internal rotation excursion from IC to 50 ms after IC. To avoid a large knee abduction and internal rotation motion during jump-landing training, it might be beneficial to provide landing instructions to avoid a large hip external rotation motion.

Differences in lower-limb biomechanics during single-leg landing considering two peripheral fatigue tasks

Dynamic knee valgus (DKV) occurs during landing after a fatigue task involving the lower extremity. However, the manner in which different peripheral fatigue tasks affect DKV remains unknown. In this study, we investigated the DKV via electromyography during single-leg landing considering the hip-joint fatigue task (HFT) and knee-joint fatigue task (KFT) performed by healthy men. We recruited 16 healthy male participants who performed a single-leg jump-landing motion from a height of 20 cm before and after an isokinetic hip abduction/adduction task (HFT) and knee extension/flexion task (KFT). Three-dimensional motion analysis systems were attached to the left gluteus medius and quadriceps, and surface electromyography was used to analyze the lower limb kinematics, kinetics, and muscle activity. The primary effects and interactions of the task and fatigue were identified based on the two-way repeated-measures analysis of variance. The results of the average angle during landing indicated that DKV occurs in KFT, whereas HFT applies external forces that adduct and internally rotate the knee at peak vertical ground reaction force (vGRF). Furthermore, both KFT and HFT exhibited an increase in muscle activity in the quadriceps. The analysis revealed that the occurrence of DKV varies depending on the peripheral fatigue task, and the effects on average DKV during landing and DKV at peak vGRF vary depending on the peripheral fatigue task.

Effectiveness of warm-up and dynamic balance training in preventing anterior cruciate ligament injuries in college gymnasts: a 3-year prospective study for one team

BACKGROUND

The effect of trunk stability and dynamic balance warm-up exercises on physical functional improvement remains unelucidated. This study examined whether exercises could prevent anterior cruciate ligament (ACL) injury and improve trunk muscle activation and dynamic balance in gymnasts.

METHODS

This comparison study, involving gymnastics practice sessions, included 31 university gymnasts and was conducted in two periods: 1 year of observation followed by 2 years of intervention. Participants performed a trunk and dynamic balance warm-up exercise program during the intervention. The effect of exercise on the incidence of ACL injury was evaluated. In addition, the paired t-test was used to compare the Y-balance distance and the changes in muscle thickness associated with trunk muscle activation at rest and during plank.

RESULTS

ACL injury risk during the intervention was significantly lower, with a relative risk of 0.23 (P=0.02, 95% CI: 0.06-0.88). Changes in muscle thickness with activation of the transversus abdominis (P<0.01, mean difference 4.1, 95% CI: 9.97-28.07, Cohen's d=0.52), internal oblique (P<0.01, mean difference 5.2, 95% CI: 9.72-21.55, Cohen's d=0.65), and external oblique (P<0.01, mean difference 5.5, 95% CI: 20.44-39.09, Cohen's d=0.71) muscles were significantly higher during the intervention. The Y-balance distance was also significantly greater in the posterior medial reach (P<0.01, mean difference 3.3, 95% CI: 1.56-6.26, Cohen's d=0.46) during the intervention.

CONCLUSIONS

Exercise-based warm-up programs may decrease ACL injuries. It can improve physical functions, such as the rate of change in trunk muscle thickness and the posterior medial distance during Y balance.

A multicomponent neuromuscular warm-up program reduces lower-extremity injuries in trained basketball players: a cluster randomized controlled trial

OBJECTIVE

To assess the effects of a novel multicomponent neuromuscular warm-up program on lower-extremity injury incidence in basketball players competing at the regional level.

METHODS

A cluster randomized controlled experimental design was adopted to compare injury incidence between players exposed to the injury prevention warm-up program and those exposed to a typical warm-up program across an entire basketball season. Four teams consisting of 57 players (male: n = 42; female: n = 15) were allocated to the intervention group (age: 21.6 ± 2.5 years; height: 186.2 ± 8.8 cm; body mass: 80.0 ± 10.4 kg) and four teams consisting of 55 players (male: n = 43; female: n = 12) were allocated to the control group (age: 21.6 ± 2.6 years; height: 186.9 ± 9.1 cm; body mass: 81.5 ± 10.9 kg). The novel warm-up combined running exercises with active stretching, plyometrics, balance, strength, and agility drills. Coaching and medical staff provided details on injury incidence each week. Data analyses included the use of poisson regression analyses and the incidence rate ratio (IRR) with 95% confidence intervals (CI).

RESULTS

The intervention group experienced a significantly lower ankle sprain incidence rate (IRR = 0.26, 95% CI = 0.05, 0.98, p = 0.02) and a tendency toward a lower knee injury incidence rate (IRR = 0.32, 95% CI = 0.03, 1.78, p = 0.07) compared to the control group. Considering only non-contact lower-extremity injuries of any type, the intervention group experienced a significantly lower incidence rate compared to the control group (IRR = 0.26, 95% CI = 0.05, 0.98, p < 0.001).

CONCLUSION

This multi-team study demonstrated a novel multicomponent warm-up program resulted in less lower-extremity injuries, particularly ankle sprains and knee injuries, compared to a typical warm-up program in regional-level male and female basketball players.

Risk factors of lower extremity injuries in youth athletes

Objective

Lower extremity sports injuries frequently occur during an individual's growth period. The object of the current study was to analyse the risk factors for lower extremity sports injuries for youth athletes. The secondary objective was to clarify the factors related to new injuries after a lower extremity injury.

Methods

We extracted information on youth athletes (aged 10-15 years) with sports-related disorders. Background data and injury situations were collected via a specific application. During the follow-up period, new injuries were also recorded. The athletes were divided into two groups according to injury location (lower extremity or other). We performed a multiple logistic regression analysis to clarify the association between injury location and background data.

Results

1575 complaints of lower extremity disorders and 328 complaints in other body parts were registered. According to the multiple regression analysis, practice time per week was significantly shorter for the lower extremity group than the other locations group (OR 0.98; 95% CI 0.963 to 0.999). Athletes whose future goal was at the recreational level had a significantly low incidence of new injuries after experiencing lower extremity disorders.

Conclusion

The practice environments and psychological factors should receive more attention to prevent lower extremity injuries.

Pelvic Rotation Is Associated With Asymmetry in the Knee Extensor Moment During Double-Leg Squatting After Anterior Cruciate Ligament Reconstruction

Asymmetry in knee extensor moment during double-leg squatting was observed after anterior cruciate ligament reconstruction, even after the completion of the rehabilitation program for return to sports. The purpose of this study was to clarify the association between asymmetry in the knee extensor moment and pelvic rotation angle during double-leg squatting after anterior cruciate ligament reconstruction. Twenty-four participants performed double-leg squatting. Kinetics and kinematics during squatting were analyzed using a 3-dimensional motion analysis system with 2 force plates. The limb symmetry index of knee extensor moment was predicted by the pelvic rotation angle (R2 = .376, P = .001). In addition, the pelvic rotation and the limb symmetry index of the vertical ground reaction force independently explained the limb symmetry index of the knee extensor moment (R2 = .635, P < .001, β of pelvic rotation = -0.489, β of vertical ground reaction force = 0.524). Pelvic rotation toward the involved limb was associated with a smaller knee extensor moment in the involved limb than in the uninvolved limb. The assessment of pelvic rotation would be useful for partially predicting asymmetry in the knee extensor moment during double-leg squatting. Minimizing pelvic rotation may improve the asymmetry in the knee extensor moment during double-leg squatting after anterior cruciate ligament reconstruction.

Exercise-Based Knee and Anterior Cruciate Ligament Injury Prevention

The Academy of Orthopaedic Physical Therapy and the American Academy of Sports Physical Therapy have an ongoing effort to create evidence-based clinical practice guidelines (CPGs) for orthopaedic and sports physical therapy management and prevention of musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability and Health (ICF). This guideline focuses on the exercise-based prevention of knee injuries and provides an update on the 2018 guideline, J Orthop Sports Phys Ther. 2018;48(9):A1-A42. doi:10.2519/jospt.2018.0303 J Orthop Sports Phys Ther. 2023;53(1):CPG1-CPG34. doi:10.2519/jospt.2023.0301.

Higher Adherence to Anterior Cruciate Ligament Injury Prevention Programs Is Associated With Lower Injury Rates: A Meta-Analysis and Meta-Regression

Background: Athletes who participate in sports that involve cutting and pivoting movements are particularly susceptible to anterior cruciate ligament (ACL) injury. Preventing this injury is the best way to combat its health consequences and costs. There may be a dose-response relationship between adherence and injury reduction. Purpose: We sought to examine whether athletes’ adherence to injury prevention programs (IPPs) is associated with reductions in ACL and lower extremity (LE) injuries. Methods: We conducted a systematic review of the PubMed, EMBASE, and Cochrane Library databases, searching for studies published between 2011 and 2021. Studies were included if they reported on the use of an ACL IPP compared with a control group and recorded the rate of injuries to calculate a rate ratio, as well as adherence to the program as a percentage of sessions performed. For the meta-analysis, the rate ratios were pooled using the DerSimonian-Laird random-effects model. Results: For the 15 studies included (11 randomized controlled trials and 4 cohort studies), the random-effects model grouped athletes’ adherence to an IPP as high (76% or more of the sessions), moderate (51%–75% of the sessions), and low (50% or fewer of the sessions). We found that athletes with the highest level of IPP adherence had a significantly lower incidence of ACL injury. The rate ratios for moderate and low adherence did not demonstrate a reduced incidence of ACL injury. Injury prevention program participation was also associated with a decrease in LE injury rates. Conclusion: This systematic review and meta-analysis found that athletes with high adherence to IPPs had reduced rates of ACL and LE injuries. Our findings suggest that educating coaches and athletes on the dose-dependent benefits of IPPs may promote the routine incorporation of these programs into warm-up sessions to decrease the risk of ACL and LE injuries.

Context of injury prevention strategies in Swiss basketball: survey of athletes, medical staff and coaches

Objectives

This project aims to assess opinions, attitudes, knowledge, beliefs, practices and perceived barriers and facilitators of injury prevention (IP) strategies in Swiss basketball teams.

Methods

An online survey was sent to athletes, coaches and medical staff of the three best basketball leagues in Switzerland. The survey was subdivided in four sections: (1) characteristic of participants, (2) knowledge, opinions, attitudes and beliefs, (3) practices and (4) barriers and facilitators.

Results

Among 105 persons (n=45 female, n=60 male) who answered the survey, more than 60% (n=68) considered the risk of injury for basketball athletes as being high to very high. The ankle, knee and the hand were considered as being the most at risk. More than 80% of participants considered that recovery, training load and the warm-up quality were very important factors for IP. More than 90% of participants considered IP as either important or very important with 53 (50.5%) of the participants indicating using exercise-based IP in their clubs. Athletes and coaches' motivation and compliance were judged as either important or very important for successful IP implementation by more than 80% of participants, with the coach being reported as the most influential person. Environmental barriers towards human or infrastructural resources were also reported as factors influencing IP strategies, namely by female participants.

Conclusion

Good knowledge and positive attitude towards IP were reported by participants, but exercise-based IP strategies lack implementation. The coach was considered as the most influential person and was reported with the athletes as playing an important role towards successful implementation.

Exploring pre-impact landing kinematics associated with increase and decrease in the anterior cruciate ligament injury risk

This study aimed to explore the single-legged landing kinematics that could lead to increase or decrease in the risk of anterior cruciate ligament (ACL) injury. Immediate pre-impact kinematics at the single-legged landing from 33 healthy young female handball players were evaluated. Thereafter, two-year follow-up for ACL injury incidence was conducted, in which six new ACL injuries in non-dominant leg were registered. The evaluation of pre-impact kinematics across participants was performed first by the principal component analysis to decompose them into the kinematic components (KCs), and then by the linear discrimination analysis (LDA) for a set of KC-scores to obtain important KCs for discriminating injured and non-injured legs. The result of LDA showed that the combination of second major KC (knee flexion/extension angle and angular velocity) and some minor KCs such as torso medial/lateral leaning accurately discriminated the injured and non-injured legs with the error rate of 12.5%. To examine the mechanisms of this discriminative ability, we generated hypothetical pre-impact kinematics in the subspaces spanned by eigenvectors of multiple KCs, and examined relationships between pre-impact kinematics and the corresponding knee valgus torque predicted by the motion-equation-based model. The result showed that the second major KC and the minor KCs representing torso medial/lateral leaning and/or hip adduction/abduction angle, which contributed in LDA to discriminating injured legs, also significantly affected the frontal-plane knee loading patterns. These findings suggested that KC-based postural characterization of the pre-impact landing kinematics and the motion-equation-based knee stress quantification possibly explain the future ACL injury risks of female athletes.

Athletes with high knee abduction moments show increased vertical center of mass excursions and knee valgus angles across sport-specific fake-and-cut tasks of different complexities

Young female handball players represent a high-risk population for anterior cruciate ligament (ACL) injuries. While the external knee abduction moment (KAM) is known to be a risk factor, it is unclear how cutting technique affects KAMs in sport-specific cutting maneuvers. Further, the effect of added game specificity (e.g., catching a ball or faking defenders) on KAMs and cutting technique remains unknown. Therefore, this study aimed: (i) to test if athletes grouped into different clusters of peak KAMs produced during three sport-specific fake-and-cut tasks of different complexities differ in cutting technique, and (ii) to test whether technique variables change with task complexity. Fifty-one female handball players (67.0 ± 7.7 kg, 1.70 ± 0.06 m, 19.2 ± 3.4 years) were recruited. Athletes performed at least five successful handball-specific sidestep cuts of three different complexities ranging from simple pre-planned fake-and-cut maneuvers to catching a ball and performing an unanticipated fake-and-cut maneuver with dynamic defenders. A k-means cluster algorithm with squared Euclidean distance metric was applied to the KAMs of all three tasks. The optimal cluster number of koptimal = 2 was calculated using the average silhouette width. Statistical differences in technique variables between the two clusters and the tasks were analyzed using repeated-measures ANOVAs (task complexity) with nested groupings (clusters). KAMs differed by 64.5%, on average, between clusters. When pooling all tasks, athletes with high KAMs showed 3.4° more knee valgus, 16.9% higher downward and 8.4% higher resultant velocity at initial ground contact, and 20.5% higher vertical ground reaction forces at peak KAM. Unlike most other variables, knee valgus angle was not affected by task complexity, likely due to it being part of inherent movement strategies and partly determined by anatomy. Since the high KAM cluster showed higher vertical center of mass excursions and knee valgus angles in all tasks, it is likely that this is part of an automated motor program developed over the players' careers. Based on these results, reducing knee valgus and downward velocity bears the potential to mitigate knee joint loading and therefore ACL injury risk.

Prospective epidemiological study of basketball injuries during one competitive season in professional and amateur Spanish basketball

INTRODUCTION

There are few Spanish epidemiological studies of basketball injuries, even though it is the second most played sport and the leading sport played by females in Spain.

POPULATION

We studied 117 male and female basketball players from ten amateur or professional teams from four leagues in the 2014-2015 season.

RESULTS

There were 11.6 injuries per 1,000 hours of sporting activity, 9.6 injuries per 1,000 hours of training and 47.3 injuries per 1,000 hours of competition. The rate of injuries requiring downtime was 2.99 per 1,000 hours of training, 41.7 per 1,000 hours of competition and 4.1 per 1,000 hours of sporting activity overall. No significant differences were found in the incidence of injuries between leagues, but a higher incidence by season was found in teams participating in international competitions, due to the increased competition time. The ankle was the main site of injuries causing ≥ 8 days of downtime and knee injuries the site of those causing ≥ 29 days of downtime. The most frequent injuries were sprains, bruises, and muscle overloads and 63.8% of players had ≥ 1 potentially-recurring injury. The most prevalent injuries were ankle sprains (50%), thigh muscle injuries (12.2%) and knee tendinitis (7.4%). The only significant predisposing factor for injury was recurrent injury (adjusted OR 1.93, 95% CI 1.029-3.62). Age, sex, height, weight, position, body mass index, and professional/amateur competition were not significantly associated with the number of injuries or ≥ 7 days downtime in the multivariate analysis.

CONCLUSION

Preventive measures should be applied to the team as a whole at an early age, since recurrent injuries only explained a small percentage of the total injuries.

Sex difference in frontal plane hip moment in response to lateral trunk obliquity during single-leg landing

BACKGROUND

Lateral trunk obliquity during landing is a characteristic of anterior cruciate ligament (ACL) injuries in female athletes and affects their knee and hip kinetics and kinematics. However, it is unclear whether these effects differ between females and males. The purpose of this study was to compare the effects of lateral trunk obliquity on knee and hip kinetics and kinematics in females and males during single-leg landing.

METHODS

Eighteen female (aged 22.1 ± 1.5 years) and 18 male participants (aged 21.8 ± 1.1 years) performed single-leg landings under two conditions: (1) without any instructions about trunk position (natural) and (2) with leaning their trunks laterally 15° from the vertical line (trunk obliquity). The kinetics and kinematics of their hip and knee were analyzed using a three-dimensional motion analysis with a force plate. Two-way repeated-measures ANOVA (sex × trunk obliquity) and Bonferroni pairwise comparisons were conducted.

RESULTS

The trunk obliquity angle at initial contact was significantly greater in the trunk-obliquity landing condition than in the natural landing condition (natural 4.0 ± 2.2°, trunk-obliquity 15.1 ± 3.6°, P < 0.001) with no sex difference (95% CI - 1.2 to 2.2°, P = 0.555). The peak knee abduction moment was significantly larger in the trunk-obliquity landing condition than in the natural landing condition (trunk-obliquity, 0.09 ± 0.07 Nm/kg/m; natural, 0.04 ± 0.06 Nm/kg/m; P < 0.001), though there was no sex or interaction effect. A significant interaction between sex and landing condition was found for the peak hip abduction moment (P = 0.021). Males showed a significantly larger peak hip abduction moment in the trunk-obliquity landing condition than in the natural landing condition (95% CI 0.05 to 0.13 Nm/kg/m, P < 0.001), while females showed no difference in the peak hip abduction moment between the two landing conditions (95% CI - 0.02 to 0.06 Nm/kg/m, P = 0.355).

CONCLUSIONS

The knee abduction moment increased with a laterally inclined trunk for both female and male participants, while the hip abduction moment increased in males but not in females. It may be beneficial for females to focus on frontal plane hip joint control under lateral trunk-obliquity conditions during single-leg landing.

Prevention of Non-Contact Anterior Cruciate Ligament Injuries among Youth Female Athletes: An Umbrella Review

Anterior cruciate ligament (ACL) injuries account for a large percentage of knee injuries, disproportionately affecting female athletes. To help health professionals stay current, we performed an umbrella review to evaluate the effectiveness of ACL injury prevention programs in reducing non-contact ACL injury rates, determine the effective components within interventions, and provide clinical recommendations. Twelve databases (Medline, Embase, Cochrane Database of Systematic Reviews, SPORTDiscus, Cumulative Index to Nursing and Allied Health Literature, PEDro, Web of Science Core Collection, Epistemonikos, TRIP, BC Guidelines and Protocols, CPG Infobase, ProQuest Dissertations and Theses Global) were searched in May 2021 to identify relevant systematic reviews and meta-analyses. Four databases were searched again in September 2021 to identify recent primary literature. Non-contact ACL injury data were extracted to calculate incidence rate ratios (IRRs) and these were combined using an inverse variance random-effects model. A qualitative assessment of included reviews was performed. The methodological quality of the studies was assessed using a Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) or Cochrane Risk-of-Bias Tool for Randomized Trials (RoB 2). Sixteen reviews and two primary studies met the inclusion criteria. Across 11 primary studies, prevention programs were effective in reducing non-contact ACL injuries by 64% (IRR = 0.36 (95% CI: 0.18-0.70)). A multi-faceted exercise program, beginning in the pre-season and containing at least three exercise types, may be beneficial in reducing ACL injury risk.

Hip torques and the effect of posture in side-stepping with elastic resistance

BACKGROUND

The way movement-based exercises affect targeted muscles is not always obvious. Side stepping with an elastic band around the forefeet is aimed at strengthening hip abductors and lateral rotator muscles, with the premise that it creates an external torque of adduction and medial rotation of the femur around the pelvis that needs to be counteracted by hip muscles. However, hip torques during this exercise have not been previously quantified.

RESEARCH QUESTION

Is the premise that the side-stepping exercise creates an external torque of adduction and medial rotation of the femur around the pelvis correct?

METHODS

Thirty-six adults performed the exercise in an upright and a squat posture while 3D kinetic and kinematic data were collected. Hip muscle torques were calculated using inverse dynamics. The effect of posture and potential interactions with sex, side-stepping phases, and trailing/leading directions were analyzed using Pearson correlation and mixed-model ANOVAs.

RESULT

A hip net muscle torque of extension, abduction and medial rotation was required to perform the exercise, regardless of phase and direction. The net muscle torque towards medial rotation required during the exercise was smaller (P < 0.001) in the upright (0.05-0.12 N m kg^-1 m^-1 across phases) compared to the squat posture (0.10-0.24 N m kg^-1 m^-1). In contrast, hip abductor torque was not affected by posture. When averaged across phases and directions, the normalized hip medial rotator muscle torque was highly correlated with knee flexion (r = 0.93, P < 0.001).

SIGNIFICANCE

The assumption that the side-stepping with the elastic band on the forefeet creates an external hip torque of medial rotation is erroneous. The resistance imposed to the hip during this exercise is consistent with the goal of strengthening the muscles that contribute to hip abduction and hip medial (not lateral) rotation. Changing the knee flexion angle is an effective way to manipulate hip rotator torque when prescribing this exercise in strength training and rehabilitation programs.

Descriptive epidemiology of injuries in Japanese collegiate men's basketball: 2013/2014 to 2019/2020

Background

Basketball is one of the most played sports in the world. However, only a few studies have examined the epidemiology of Japanese collegiate men’s basketball injuries. This study investigated the incidence of injury among Japanese collegiate men’s basketball from the 2013/2014 to the 2019/2020 seasons and identified unique patterns by comparing our data with the National Collegiate Athletic Association (NCAA) men’s basketball data.

Methods

Data from Japanese collegiate basketball teams of the Kanto Collegiate Basketball Federation Division I League during the 2013/2014 to 2019/2020 academic years (23 team-seasons) were used in this study. Injury rates per 1000 athlete exposures (AEs), injury proportions, and the injury rate ratio (IRR) were calculated according to the events, injury types, body parts, and common injury mechanisms. Injury rates were then compared with that from the time-loss injury data of the NCAA’s previous reports.

Results

In total, 480 injuries during 97,515 AEs were reported, leading to an injury rate of 4.92 per 1000 AEs (95% CI = 4.48–5.36). The overall injury rate was higher in Japan than in the NCAA ([2009/2010–2014/2015] IRR = 1.55, 95% CI = 1.39–1.73; [2014/2015–2018/2019] IRR = 1.64, 95% CI = 1.48–1.82). Lower extremity injuries occurred most frequently (73.5%). Ankle sprain was the most common injury in Japan, with higher injury rates than in the NCAA (IRR = 2.10; 95% CI = 1.72–2.57). The injury rate of concussion was lower in Japan than in the NCAA (IRR = 0.28; 95% CI = 0.14–0.55).

Conclusions

The rates of overall injury and ankle sprain were higher and that of concussion was lower in Japan than in the NCAA. These results suggested the existence of international differences in the pattern or features of injuries in basketball players.

The top 100 most impactful articles on the anterior cruciate ligament: An altmetric analysis of online media

Objectives:

To identify the top 100 most impactful anterior cruciate ligament articles in online media as measured by the Altmetric Attention Score and compare their characteristics to the most-cited anterior cruciate ligament articles in the scientific literature.

Methods:

The Altmetric database was queried to identify all published articles pertaining to the anterior cruciate ligament. The search yielded 9445 articles, which were stratified by highest to lowest Altmetric Attention Score. The top 100 articles were included. Collected data included article type, article topic, journal name, and online mentions in news, blogs, Twitter, Facebook, Wikipedia, and other sources. The geographic origin of each article was also determined based on the institutional affiliation of the first author.

Results:

Altmetric Attention Score of the top 100 anterior cruciate ligament articles ranged from 109 to 2193 (median 172.0, interquartile range 137.5–271.5). Of the 100 articles, 65 were published in three journals: American Journal of Sports Medicine, British Journal of Sports Medicine, and Journal of Orthopaedic & Sports Physical Therapy. The most prevalent article type was original research (60%), followed by systematic review/meta-analysis (18%). The most prevalent article topic was rehabilitation and return to play after anterior cruciate ligament reconstruction (22%), followed by epidemiology/risk factors (16%), injury prevention (14%), and biomechanics of anterior cruciate ligament injuries (14%). Of the top 100 articles, 54% were American, 31% were European, and 15% were published in other countries outside of the United States and Europe.

Conclusion:

This study used Altmetric Attention Score to identify the 100 most engaged anterior cruciate ligament articles in online media. The characteristics of these articles differed substantially from the most-cited anterior cruciate ligament articles in the literature with regard to article type, article topic, geographic origin, and publication journal. These findings suggest that alternative metrics measure distinct components of anterior cruciate ligament article engagement and add an important dimension to understanding the overall impact of published research on the anterior cruciate ligament.

Effects of Hypopressive Exercise on Posterior Back Chain Kinematics and Pulmonary Function in Professional Female Basketball Players

CONTEXT

Hypopressive exercise (HE) has been used as an alternative lumbo-pelvic injury prevention program and claimed to be a means of respiratory and flexibility improvement. However, the possible effects of HE on athletic populations and physical performance remain unclear.

OBJECTIVE

Examine the effects of a HE program on posterior back chain kinematics, thoracic mobility, pulmonary function, and lower lumbar pain in female basketball players over an 8-week training period.

DESIGN

Prospective (1) baseline, (2) midpoint (4 wk), and (3) after 8 weeks.

SETTING

Sports field.

PARTICIPANTS

A total of 17 professional female basketball players (mean age 20.7 y, SD: 3.50; body mass index, 21.71, SD: 1.69).

INTERVENTION

Participants performed 8 HE weekly sessions of 30 minutes.

MAIN OUTCOME MEASURES

Back chain kinematics was assessed with the sit and reach and finger to floor test, and back pain was assessed through numerical rating scale. Respiratory parameters were assessed by spirometry and through thoracic mobility.

RESULTS

The analysis of variance revealed significant differences between the 3 measurement periods for thoracic mobility (P > .01); forced expiratory volume in the first second (P < .05) while no statistical differences were found for the rest of spirometry outcomes. Significant differences were also revealed between baseline and after the intervention for the sit and reach test (P > .01), peak expiratory flow (P = .01), and forced expiratory volume in the first 25 seconds (P = .04). Also, significant differences between weeks were found in levels of lumbar pain (P = .003) and the finger to floor test (P = .002).

CONCLUSIONS

These preliminary findings suggest that a HE program can improve posterior back chain and chest wall kinematics as well as lower lumbar pain levels. However, no gains seem to be observed for the majority of pulmonary variables except for peak expiratory flow and forced expiratory volume in the first seconds.

Effects of foot progression angle on knee mechanics during an anticipated cutting task: A statistical parametric mapping approach

Cutting is considered a "high-risk" movement for anterior cruciate ligament (ACL) injuries. It has been established that sex differences exist during cutting, placing females at greater ACL injury risk. Foot progression angle (FPA) during landing has been shown to influence lower extremity mechanics, yet little is known how FPA influences mechanics during cutting. The purpose of this study was to compare two FPA conditions during cutting between males and females. Twenty-four males and females were tested using two FPA conditions: toe-in 15° (TI15) and toe-out 15° (TO15). Right knee joint kinematic and kinetic variables were measured using a motion capture system and force plate. Five successful trials were collected and compared between FPA conditions. One-dimensional statistical parametric mapping was used to assess changes in knee mechanics between males and females over the entire stance phase. The only sex × FPA effect found was knee flexion angle. Females cutting at TI15 had decreased knee flexion angle compared TO15 (p = 0.019). Significant sex main effects included knee abduction and rotation angles, and knee flexion and rotation moments. Significant FPA main effects included knee flexion, abduction and rotation angles. The results show cutting with a toe-in FPA of 15° is enough to induce changes in knee abduction angle while cutting with 15° toe-out FPA influenced knee flexion and rotation angles. These data suggest that different cutting FPAs may be influential on known ACL injury risk variables. However, more research is warranted on cutting FPA before FPA is targeted as part of ACL injury prevention protocols.

Effect of Rearfoot Strikes on the Hip and Knee Rotational Kinetic Chain During the Early Phase of Cutting in Female Athletes

BACKGROUND

Biomechanical factors affecting horizontal-plane hip and knee kinetic chain and anterior cruciate ligament (ACL) injury risk during cutting maneuvers remain unclear. This study aimed to examine whether different foot strike patterns alter horizontal-plane hip and knee kinetics and kinematics during a cutting maneuver in female athletes and clarify the individual force contribution for producing high-risk hip and knee loadings. Twenty-five healthy female athletes performed a 60° cutting task with forefoot and rearfoot first strike conditions. Horizontal-plane hip and knee moment components, angles, and angular velocities were calculated using synchronized data of the marker positions on the body landmarks and ground reaction forces (GRFs) during the task. The one-dimensional statistical parametric mapping paired t test was used to identify the significant difference in kinetic and kinematic time-series data between foot strike conditions.

RESULTS

In the rearfoot strike condition, large hip and knee internal rotation loadings were produced during the first 5% of stance due to the application of GRFs, causing a significantly larger hip internal rotation excursion than that of the forefoot strike condition. Dissimilarly, neither initial hip internal rotation displacement nor knee internal rotation GRF loadings were observed in the forefoot strike condition.

CONCLUSIONS

Rearfoot strike during cutting appears to increase noncontact ACL injury risk as the GRF tends to produce combined hip and knee internal rotation moments and the high-risk lower limb configuration. Conversely, forefoot strike during cutting appears to be an ACL-protective strategy that does not tend to produce the ACL-harmful joint loadings and lower extremity configurations. Thus, improving foot strike patterns during cutting should be incorporated in ACL injury prevention programs.

The Effectiveness of Neuromuscular Warmups for Lower Extremity Injury Prevention in Basketball: A Systematic Review

BACKGROUND

Neuromuscular warmups have gained increasing attention as a means of preventing sports-related injuries, but data on effectiveness in basketball are sparse. The objective of this systematic review was to evaluate evidence of the effectiveness of neuromuscular warmup-based strategies for preventing lower extremity injuries among basketball athletes.

METHODS

PubMed and Cochrane Library databases were searched in February 2019. Studies were included if they were English-language randomized controlled, non-randomized comparative, or prospective cohort trials, tested neuromuscular and/or balance-focused warmup interventions among basketball players, and assessed at least one type of lower extremity injury as a primary outcome. Criteria developed by the USPSTF were used to appraise study quality, and GRADE was used to appraise the body of evidence for each outcome. Due to heterogeneity in the included studies, meta-analyses could not be performed.

RESULTS

In total, 825 titles and abstracts were identified. Of the 13 studies which met inclusion criteria for this review, five were balance interventions (3 randomized controlled trials) and eight were multicomponent interventions involving multiple categories of dynamic neuromuscular warmup (5 randomized controlled trials). Authors of four of the studies were contacted to obtain outcome data specific to basketball athletes. Basketball specific results from the studies suggest significant protective effects for the following lower extremity injuries: ankle injuries (significant in 4 out of the 9 studies that assessed this outcome); ACL injuries (2 of 4 studies); knee injuries generally (1 of 5 studies); and overall lower extremity injuries (5 of 7 studies). All but one of the non-significant results were directionally favorable. Evidence was moderate for the effect of multicomponent interventions on lower extremity injuries generally. For all other outcomes, and for balance-based interventions, the quality of evidence was rated as low.

CONCLUSION

Overall, the evidence is supportive of neuromuscular warmups for lower extremity injury prevention among basketball players. However, most studies are underpowered, some used lower-quality research study designs, and outcome and exposure definitions varied. Due to the nature of the study designs, effects could not be attributed to specific intervention components. More research is needed to identify the most effective bundle of warmup activities.

Activation of the gluteus maximus, gluteus medius and tensor fascia lata muscles during hip internal and external rotation exercises at three hip flexion postures

BACKGROUND

Hip internal and external rotation exercises are usually performed in clinical practice. However, given the synergies required to stabilize the hip in the frontal plane, it is not clear how the activation of target muscles will differ between the two exercise directions.

OBJECTIVE

I) Compare the activation of the upper and lower fibers of gluteus maximus (GMax), gluteus medius (GMed) and tensor fascia lata muscles between the hip internal and external rotation exercises; ii) Compare the maximal isometric force between hip internal and external rotation exercises and; iii) Assess the effect of varying hip flexion angles on muscle activation and maximal isometric force.

STUDY DESIGN

A cross sectional study.

METHODS

Electromyography and force production of twenty-one participants were measured during maximum isometric hip internal and external rotation in three postures: 0°, 45° and 90° of hip flexion.

RESULTS

MANOVA results showed a larger activation of the GMed, tensor fascia lata and upper GMax (p < .001) for hip internal rotation compared to external rotation regardless of hip flexion angle. For the lower GMax, the same was observed when the hip was kept at 90° of flexion. Maximal isometric force during hip external rotation was greater than during hip internal rotation at 0° posture, and lower at 90° posture (p < .001).

CONCLUSION

The gluteus and the tensor fascia lata muscles were substantially recruited during the hip internal rotation exercise, and barely recruited during the hip external rotation exercise. Hip flexion influences the myoeletric activity and isometric force production during the internal rotation exercise.

Anterior Cruciate Ligament Loading Increases With Pivot-Shift Mechanism During Asymmetrical Drop Vertical Jump in Female Athletes

Background:

Frontal plane trunk lean with a side-to-side difference in lower extremity kinematics during landing increases unilateral knee abduction moment and consequently anterior cruciate ligament (ACL) injury risk. However, the biomechanical features of landing with higher ACL loading are still unknown. Validated musculoskeletal modeling offers the potential to quantify ACL strain and force during a landing task.

Purpose:

To investigate ACL loading during a landing and assess the association between ACL loading and biomechanical factors of individual landing strategies.

Study Design:

Descriptive laboratory study.

Methods:

Thirteen young female athletes performed drop vertical jump trials, and their movements were recorded with 3-dimensional motion capture. Electromyography-informed optimization was performed to estimate lower limb muscle forces with an OpenSim musculoskeletal model. A whole-body musculoskeletal finite element model was developed. The joint motion and muscle forces obtained from the OpenSim simulations were applied to the musculoskeletal finite element model to estimate ACL loading during participants’ simulated landings with physiologic knee mechanics. Kinematic, muscle force, and ground-reaction force waveforms associated with high ACL strain trials were reconstructed via principal component analysis and logistic regression analysis, which were used to predict trials with high ACL strain.

Results:

The median (interquartile range) values of peak ACL strain and force during the drop vertical jump were 3.3% (–1.9% to 5.1%) and 195.1 N (53.9 to 336.9 N), respectively. Four principal components significantly predicted high ACL strain trials, with 100% sensitivity, 78% specificity, and an area of 0.91 under the receiver operating characteristic curve (P < .001). High ACL strain trials were associated with (1) knee motions that included larger knee abduction, internal tibial rotation, and anterior tibial translation and (2) motion that included greater vertical and lateral ground-reaction forces, lower gluteus medius force, larger lateral pelvic tilt, and increased hip adduction.

Conclusion:

ACL loads were higher with a pivot-shift mechanism during a simulated landing with asymmetry in the frontal plane. Specifically, knee abduction can create compression on the posterior slope of the lateral tibial plateau, which induces anterior tibial translation and internal tibial rotation.

Clinical Relevance:

Athletes are encouraged to perform interventional and preventive training to improve symmetry during landing.

Effect of Graft Rupture Prevention Training on Young Athletes After Anterior Cruciate Ligament Reconstruction: An 8-Year Prospective Intervention Study

Background:

There is a lack of research on the effects of a postoperative rehabilitation program on anterior cruciate ligament (ACL) graft rupture.

Hypothesis:

We hypothesized that a hip-focused rehabilitation protocol with graft rupture education and avoidance training (HIP-GREAT program) would demonstrate lower ACL graft rupture rates compared with a traditional physical therapy (PT) program.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This study consisted of young athletes who had undergone ACL reconstruction at a single institution. Postoperatively, 136 participants (mean age, 16.9 ± 2.4 years) were enrolled in a traditional PT protocol between 2006 and 2010, and 153 participants (mean age, 17.0 ± 2.3 years) were enrolled in the HIP-GREAT protocol between 2011 and 2015. Follow-up rates were 31% (42/136) and 27% (41/153) in the traditional PT and HIP-GREAT groups, respectively, at 3 years postoperatively. The hazard ratio was calculated, and absolute risk reduction (ARR) and number-needed-to-treat (NNT) analyses were performed to compare the 2 protocols.

Results:

ACL graft rupture occurred in 10 patients (7.4%) in the traditional PT group and 5 patients (3.3%) in the HIP-GREAT group. This difference was not statistically significant (hazard ratio, 0.39; 95% CI, 0.14 to 1.16; P = .09). The ARR was 0.041 (95% CI, –0.011 to 0.093), and the NNT was 24.5.

Conclusion:

This study did not demonstrate a statistically significant reduction of ACL graft rupture in patients in the HIP-GREAT group. However, high ARR values and low NNT values were found, which suggests the possible effectiveness of the HIP-GREAT protocol to reduce ACL graft ruptures in young athletes.

Improvements in Hip Extensor Rate of Torque Development Influence Hip and Knee Extensor Feed-Forward Control

Females have been reported to utilize a feedforward control strategy during landing in which they compensate for decreased rate of torque development (RTD) of the hip extensors through earlier pre-activation of the knee extensors. The purpose of this study was to determine the influence of a 4-week hip-focused training program on hip extensor RTD and feedforward control of the hip and knee extensors. Twenty-one females underwent hip extensor RTD evaluation and electromyographic assessment of the hip and knee extensors during a drop-jump task. Post-training, there was a significant improvement in hip extensor RTD (21.68 ± 5.44 to 23.33 ± 5.45 Nm/kg s, p = 0.009), and pre-activation of the hip extensors (87.1 ± 63.6 to 56.2 ± 60.9 ms, p < 0.001) and knee extensors (272.3 ± 113.8 to 124.0 ± 67.7 ms, p < 0.001) occurred closer to ground contact. A negative association was found between the change in hip extensor RTD and the change in knee extensor onset (r = -0.48, p = 0.03). We propose that the observed change in feedforward control is reflective of the decreased need for preparatory muscle activity owing to the improved capacity of the hip extensors to rapidly generate force.

Steep Posterior Tibial Slope and Excessive Anterior Tibial Translation Are Predictive Risk Factors of Primary Anterior Cruciate Ligament Reconstruction Failure: A Case-Control Study With Prospectively Collected Data

BACKGROUND

Steep posterior tibial slope (PTS) and excessive anterior tibial translation (ATT) have been identified as important anatomic risk factors for anterior cruciate ligament (ACL) injury, which have raised concerns about clinical outcomes after primary ACL reconstruction (ACLR).

PURPOSE

To investigate anatomic risk factors of primary ACLR failure and to determine the cutoff values of PTS and ATT for predicting primary ACLR failure.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Between November 2015 and May 2017, a total of 215 consecutive patients with clinically diagnosed noncontact ACL injuries who underwent primary anatomic ACLR were retrospectively analyzed. Among them, 25 patients who showed complete discontinuity of ACL fibers on final follow-up magnetic resonance imaging scans were allocated into the failure group (study group). They were matched 1:2 to 50 control participants who showed clear and continuous ACL fibers on magnetic resonance imaging scans (control group). PTS and ATT were measured on preoperative weightbearing whole leg lateral radiographs and compared between the groups. The cutoff values of PTS and ATT for predicting primary ACLR failure were determined by the receiver operating characteristic curve. Moreover, predictors of primary ACLR failure were assessed by multivariate logistic regression analysis, including sex, age, body mass index, concomitant meniscal tears, degree of pivot-shift test, and KT-1000 arthrometer side-to-side difference, PTS, and ATT.

RESULTS

PTS and ATT values in the study group were significantly higher than those in the control group (mean ± SD: PTS, 17.2°± 2.2° vs 14.4°± 2.8°; ATT, 8.3 ± 3.4 mm vs 4.1 ± 3.1 mm; P < .001). The cutoff values of PTS and ATT for predicting primary ACLR failure were 17° (sensitivity, 66.7%; specificity, 90.9%) and 6 mm (sensitivity, 87.5%; specificity, 79.5%), respectively. Additionally, PTS ≥17° (odds ratio, 15.6; 95% CI, 2.7-91.5; P = .002) and ATT ≥6 mm (odds ratio, 9.9; 95% CI, 1.9-51.4; P = .006) were determined to be risk factors of primary ACLR failure, whereas sex, age, body mass index, concomitant meniscal tears, degree of the pivot-shift test, and KT-1000 arthrometer side-to-side difference were not.

CONCLUSION

In this study, PTS ≥17° and ATT ≥6 mm, as measured on weightbearing whole leg radiographs, were identified to be predictive risk factors of primary ACLR failure. This study adds to the existing knowledge about potential surgical indications of simultaneous slope-reducing high tibial osteotomy to mitigate the primary ACLR failure rate.

Evidence-Based Best-Practice Guidelines for Preventing Anterior Cruciate Ligament Injuries in Young Female Athletes: A Systematic Review and Meta-analysis

BACKGROUND

Injury prevention neuromuscular training (NMT) programs reduce the risk for anterior cruciate ligament (ACL) injury. However, variation in program characteristics limits the potential to delineate the most effective practices to optimize injury risk reduction.

PURPOSE

To evaluate the common and effective components included in ACL NMT programs and develop an efficient, user-friendly tool to assess the quality of ACL NMT programs.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

Study inclusion required (1) a prospective controlled trial study design, (2) an NMT intervention aimed to reduce incidence of ACL injury, (3) a comparison group, (4) ACL injury incidence, and (5) female participants. The following data were extracted: year of publication, study design, sample size and characteristics, and NMT characteristics including exercise type and number per session, volume, duration, training time, and implementer training. Analysis entailed both univariate subgroup and meta-regression techniques using random-effects models.

RESULTS

Eighteen studies were included in the meta-analyses, with a total of 27,231 participants, 347 sustaining an ACL injury. NMT reduced the risk for ACL injury from 1 in 54 to 1 in 111 (odds ratio [OR], 0.51; 95% CI, 0.37-0.69]). The overall mean training volume was 18.17 hours for the entire NMT (24.1 minutes per session, 2.51 times per week). Interventions targeting middle school or high school-aged athletes reduced injury risk (OR, 0.38; 95% CI, 0.24-0.60) to a greater degree than did interventions for college- or professional-aged athletes (OR, 0.65; 95% CI, 0.48-0.89). All interventions included some form of implementer training. Increased landing stabilization and lower body strength exercises during each session improved prophylactic benefits. A meta-regression model and simple checklist based on the aforementioned effective components (slope = -0.15, P = .0008; intercept = 0.04, P = .51) were developed to allow practitioners to evaluate the potential efficacy of their ACL NMT and optimize injury prevention effects.

CONCLUSION

Considering the aggregated evidence, we recommend that ACL NMT programs target younger athletes and use trained implementers who incorporate lower body strength exercises (ie, Nordic hamstrings, lunges, and heel-calf raises) with a specific focus on landing stabilization (jump/hop and hold) throughout their sport seasons.

CLINICAL RELEVANCE

Clinicians, coaches, athletes, parents, and practitioners can use the developed checklist to gain insight into the quality of their current ACL NMT practices and can use the tool to optimize programming for future ACL NMT to reduce ACL injury risk.

The muscle pre-activity timing of the hamstrings and quadriceps during 180° and 360° rotational jump landings in healthy female subjects

Background/Objective

The muscle activity before the initial contact between during jump landings is referred to as the pre-activity. The muscle pre-activity that occur during jump landing are considered to be an important predictor of non-contact anterior cruciate ligament (ACL) injury risk. ACL injury prevention programs have been widely conducted; these programs are generally focused on increasing the muscle pre-activity and include rotational jump landing. The purpose of this study was to investigate the timing of the muscle pre-activity of the hamstrings and quadriceps during 180° and 360° rotational jump landing.

Methods

The participants were 10 healthy females. Electromyography was conducted on the knee joint muscles of the left leg (the non-dominant leg) during clockwise 180° and 360° rotational jump landings.

Results

The muscle pre-activities during 180° rotational jump landing was VM: 35.68 ± 11.22 msec, RF: 38.05 ± 14.77 msec, VL: 47.10 ± 19.96 msec, BF: 115.63 ± 30.48 msec and SM: 136.45 ± 47.52 msec. And the muscle pre-activities during 360° rotational jump landing was VM: 45.25 ± 17.41 msec, RF: 42.38 ± 13.35 msec, VL: 48.75 ± 19.20 msec, BF: 132.20 ± 46.74 msec and SM: 140.70 ± 40.64 msec. For both the 180° rotational jump landing and the 360° jump landing, the pre-activities of the hamstrings occurred significantly earlier than those of the quadriceps (p < 0.01).

Conclusion

The results of the present study indicate that it may be beneficial for ACL injury prevention programs to include rotational jump landing tasks.

Risk factors associated with self-reported injury history in female youth soccer players

BACKGROUND

studies that investigate risk factors for musculoskeletal injuries in female youth athletes are limited, especially related to training attributes and position status.

OBJECTIVE

to determine risk factors including training attributes and position status for a self-reported musculoskeletal injury history in female youth soccer players.

METHODS

we conducted a cross-sectional study of young female soccer players (mean age: 13.6 ± 2.3 years). we asked about their history of musculoskeletal injuries using an electronic questionnaire. the proportion of young female soccer players with and without a history of soccer-related musculoskeletal injuries were compared based on physical characteristics, training attributes, position status (single vs. multiple), lower extremity strength, and joint laxity. a binary logistic regression analysis was used to generate, and adjusted odds ratios adjusted for potential co-variates (aor). a 95% confidence interval (95%ci) that did not cross one or p < 0.05 were considered statistically significant.

RESULTS

a total of 160 young female soccer players (mean age: 13.6 ± 2.3 years) participated in the study. an independent association was found between prior musculoskeletal injuries and older ages (aor: 1.60, 95%ci: 1.17, 2.20, p = 0.004), higher weight (aor: 1.10, 95%ci: 1.01, 1.20, p = 0.026), and greater bmi (aor: 1.43, 95%ci: 1.07, 1.90, p = 0.014).

CONCLUSIONS

musculoskeletal injuries were associated with age, weight, and bmi in female youth players. the current study indicates that maintaining proper body composition may be beneficial to reduce musculoskeletal injuries among female youth soccer players.