Molecular biomarker approaches to prevention of post-traumatic osteoarthritis

Up to 50% of individuals develop post-traumatic osteoarthritis (PTOA) within 10 years following knee-joint injuries such as anterior cruciate ligament rupture or acute meniscal tear. Lower-extremity PTOA prevalence is estimated to account for ≥12% of all symptomatic osteoarthritis (OA), or approximately 5.6 million cases in the USA. With knowledge of the inciting event, it might be possible to 'catch PTOA in the act' with sensitive imaging and soluble biomarkers and thereby prevent OA sequelae by early intervention. Existing biomarker data in the joint-injury literature can provide insights into the pathogenesis and early risk trajectory related to PTOA and can help to elucidate a research agenda for preventing or slowing the onset of PTOA. Non-traumatic OA and PTOA have many clinical, radiological and genetic similarities, and efforts to understand early risk trajectories in PTOA might therefore contribute to the identification and classification of early non-traumatic OA, which is the most prevalent form of OA.

An 8-week injury prevention exercise program combined with change-of-direction technique training limits movement patterns associated with anterior cruciate ligament injury risk

Knee ligament sprains are common during change-of-direction (COD) maneuvers in multidirectional team sports. This study aimed to compare the effects of an 8-week injury prevention exercise program containing COD-specific exercises and a similar program containing linear sprint exercises on injury- and performance-related variables during a 135° COD task. We hypothesized that the COD-specific training would lead to (H1) stronger reductions in biomechanical variables associated with anterior cruciate ligament (ACL) injury risk during COD, i.e. knee abduction moment and angle, hip internal rotation angle and lateral trunk lean, and (H2) more effective improvements in COD performance according to the COD completion time, executed angle, ground contact time, and approach speed. Twenty-two sports science students (40% female) completed biomechanical assessments of COD movement strategies before and after participating in two supervised 25-min training sessions per week over 8 weeks. We observed significant 'training x group' interaction effects in support of H1: the COD-specific training but not the linear sprint training led to reduced peak knee abduction moments (interaction, p = 0.027), initial knee abduction (interaction, p < 0.001), and initial lateral trunk lean angles (interaction, p < 0.001) compared to baseline. Although the COD-specific training resulted in sharper executed angles (interaction, p < 0.001), the sprint-specific training group showed reduced COD completion (interaction, p = 0.037) and ground contact times (interaction, p < 0.001). In conclusion, a combination of generic and COD-specific injury prevention training resulted in COD technique adaptations that can help to avoid ACL injury-prone COD movements but may negatively affect COD speed.

The Effect of a Knee Brace on Muscle Forces during Single-Leg Landings at Two Heights

Single-leg landing is one of the maneuvers that has been linked to non-contact anterior cruciate ligament (ACL) injuries, and wearing knee braces has been shown to reduce ACL injury incidence. The purpose of this study was to determine whether wearing a knee brace has an effect on muscle force during single-leg landings at two heights through musculoskeletal simulation. Eleven healthy male participants, some braced and some non-braced were recruited to perform single-leg landings at 30 cm and 45 cm. We recorded the trajectories and ground reaction forces (GRF) using an eight-camera motion capture system and a force platform. The captured data were imported into the generic musculoskeletal model (Gait2392) in OpenSim. Static optimization was used to calculate the muscle forces. The gluteus minimus, rectus femoris, vastus medialis, vastus lateralis, vastus medialis medial gastrocnemius, lateral gartrocnemius, and soleus muscle forces were all statistically significant different between the braced and non-braced participants. Simultaneously, increasing the landing height significantly affected the gluteus maximums, vastus medialis, and vastus intermedia muscle forces. Our findings imply that wearing a knee brace may alter muscle forces during single-leg landings, preventing ACL injuries. Additionally, research demonstrates that people should avoid landing from heights due to the increased risk of knee injuries.

Preventing Knee Injuries: Exercises to Keep You From Getting Sidelined

Recently, injury prevention experts developed a guideline for rehabilitation clinicians to use to help you avoid getting another knee injury. Here, we explain what the guidelines say about which exercises you should do to stay injury-free, how often to do the exercises, and when to do the exercises. J Orthop Sports Phys Ther 2023;53(2):105. doi:10.2519/jospt.2023.0503.

Exercise-Based Interventions for Preventing Knee and Anterior Cruciate Ligament Injury: Using the Evidence to Guide Musculoskeletal Rehabilitation Practice

Knee and anterior cruciate ligament (ACL) injuries are common and can be severe. Some knee injuries carry long-term implications for the health of active people, including a risk of osteoarthritis and physical inactivity. Preventing injuries from occurring is critical to helping people stay active and healthy through their life. Here we present for clinicians, the most up-to-date information to guide their work to prevent knee and ACL injuries. J Orthop Sports Phys Ther 2023;53(2):103-104. doi:10.2519/jospt.2023.0502.

Reducing Knee Joint Load during a Golf Swing: The Effects of Ball Position Modification at Address

As the modern golf swing has changed, the incidence of knee pain in professional golfers is increasing. For those with previous knee injuries, developing a golf-swing modification that reduces knee loading may be necessary to recover performance after injury. The purpose of this study was to test whether ball position modification reduces knee joint load in a golf swing. Thirteen male professional golfers participated in the study. Golf swings were captured using a three-dimensional motion capture system and two force platforms, with conditions for self-selected ball position and eight additional ball positions. Knee internal rotation and adduction moments were calculated. The length of one golf ball (4.27 cm) backward ball position (closer to the golfer) significantly reduced the peak internal rotation moment of the lead knee (- 13.8%) (p &lt; 0.001) and the length of one golf ball (4.27 cm) away from the target ball position significantly reduced the peak adduction moment of the lead knee (- 11.5%) (p &lt; 0.001) compared with that of the self-selected ball position. Based on these observations, we conclude that the backward ball position modification might be suggested for golfers with anterior cruciate ligament injuries, and the away from the target modification might be suggested for golfers with medial compartment knee osteoarthritis.

Injury Prevention Effect of MRI Imaging Technology in Physical Education and Sports Training

In order to solve the problem of observing and analyzing the clinical value of MRI diagnosis in patients with knee sports injury and guiding clinical targeted treatment, the author proposed a sports injury prevention method in sports training teaching based on MRI image observation. This method retrospectively analyzed the imaging data of 101 patients with knee joint MRI examination due to osteoarthritis, sports injury and synovitis in joint surgery, and arthroscopic exclusion of true meniscus tear, MR multisequence and multiplane scans were performed to observe the anatomical features of TGL and MFL images and the occurrence rate of the lateral meniscus "false tear sign," and the χ ² test was used to compare the occurrence rate of "pseudo-tear sign" between genders and sides. Experimental results show that the incidence of TGL on MRI was about 67.3% (68/101), and the incidence of "pseudo-tear sign" in the anterior horn of the lateral meniscus caused by TGL was 2.9% (2/68). The overall appearance rate of MFL on MRI was 91.1% (92/101), the appearance rate of plate anterior ligament (HL) was 13.9% (14/101), and the occurrence rate of "pseudo-tear sign" in the posterior horn of the lateral meniscus caused by HL was 7.1% (1/14). The occurrence rate of the posterior ligament (WL) was 77.2% (78/101), and the incidence of "pseudo-tear sign" in the posterior horn was 20.5% (16/78). According to the shape and course of TGL and MFL on MRI, and the direction and position of the lateral meniscus pseudotear, combined with MRI sagittal plane and coronal plane observation, it can effectively identify the true and false attributes of lateral meniscus anterior and posterior horn tears, thereby reducing unnecessary surgical treatment.

"Yeah, I Mean, You're Going to Handball, so You Want to Use Balls as Much as Possible at Training": End-Users' Perspectives of Injury Prevention Training for Youth Handball Players

Young handball players experience high injury rates. Specific injury prevention programs reduce injury rates but are not well implemented into youth players’ training. The ‘Implementing injury Prevention training ROutines in TEams and Clubs in youth Team handball (I-PROTECT)’ project addresses this challenge. The aim of this study was to investigate how youth handball coaches and players experienced the recently developed I-PROTECT GO pilot program, by focusing on barriers and facilitators. Three focus group interviews were conducted with coaches and players, and their answers were analyzed using a general inductive approach. The participants appreciated the program and found it useful for their context. The participants’ statements about facilitators and barriers centered around the categories of resources, exercises, program design, and learning. Facilitators that emerged were motivating exercises (e.g., handball-specific), a helpful set-up (e.g., variation), having a clear purpose of exercises, the possibility to fulfil basic psychological needs while training, receiving instructions and feedback, and having role models. Barriers that emerged were limited space and material, difficulties with exercises, an unhelpful set-up (e.g., too repetitive), and undisciplined training. It is important to address perceived barriers and facilitators among coaches and players when developing injury prevention training programs to enhance the uptake of such training.

Custom-Fitted Compression Garments Enhance Recovery From Muscle Damage in Rugby Players

ABSTRACT

Brown, F, Jeffries, O, Gissane, C, Howatson, G, van Someren, K, Pedlar, C, Myers, T, and Hill, JA. Custom-fitted compression garments enhance recovery from muscle damage in rugby players. J Strength Cond Res 36(1): 212-219, 2022-to evaluate the effects of custom-fitted compression garments (CG) on recovery from muscle damage in rugby players. Forty-five players were tested for lower-body strength, power, and indices of muscle damage before completing a damaging protocol (20 × 20-m sprints with 5-m deceleration, 100 drop jumps). Players were randomly assigned to wear either custom-fitted (CF, n = 13), or standard-sized CG (SSG, n = 16), or to receive sham ultrasound therapy (CON, n = 16) immediately after exercise. Players were retested immediately, then after 24 and 48 hours. Strength recovery was significantly different between groups (F = 2.7, p = 0.02), with only CF recovering to baseline values by 48 hours (p = 0.973). Time × condition effects were also apparent for creatine kinase activity (χ2 = 30.4, p < 0.001) and midthigh girth (F = 3.7, p = 0.005), with faster recovery apparent in CF compared with both CON and SSG (p < 0.05). Custom-fitted CG improved strength recovery and indices of muscle damage in rugby players, compared with controls and standard-sized garments. Athletes and coaches would be advised to use appropriately fitted CG to enhance strength recovery after damaging exercise.

Healthcare Data-Based Prediction Algorithm for Potential Knee Joint Injury of Football Players

It is important to predict the potential harm to the knee joint in order to prevent football players from inflicting numerous injuries to the knee during activity. Numerous professionals have been drawn to this subject, and many viable prediction systems have been developed. Prediction of potential knee joint injury is critical to effectively avoid knee joint injury during exercise. The current prediction algorithms are mainly implemented through expert interviews, medical reports, and historical documents. The algorithms have problems with low prediction accuracy or precision values. There is a need to understand more knee injury factors and improve the prediction accuracy; hence, the intelligent prediction algorithm for potential injury of knee joints of football players is proposed in this paper. Firstly, the characteristics of the knee joint injury and the injury factors of the football players are gathered and analyzed. Then, the damage is predicted by the similarity measurement. The experimental results show that the proposed algorithm has higher prediction accuracy and shorter time. According to the findings of a survey that collected healthcare data, several key factors contribute to football knee injuries. To a degree, this algorithm can predict the likelihood of a football player's knee injury.

Factors Associated With Lower Limb Injuries in Recreational Runners: A Cross-Sectional Survey Including Mental Aspects and Sleep Quality

Knowledge about prevalence and etiology of running-related injuries (RRIs) is important to design effective RRI prevention programs. Mental aspects and sleep quality seem to be important potential risk factors, yet their association with RRIs needs to be elucidated. The aims of this study are to investigate the epidemiology of RRIs in recreational runners and the association of mental aspects, sleep, and other potential factors with RRIs. An internet-based questionnaire was sent to recreational runners recruited through social media, asking for personal and training characteristics, mental aspects (obsessive passion, motivation to exercise), sleep quality, perceived health, quality of life, foot arch type, and RRIs over the past six months. Data were analyzed descriptively and using logistic regression. Self-reported data from 804 questionnaires were analyzed. Twenty-five potential risk factors for RRIs were investigated. 54% of runners reported at least one RRI. The knee was the most-affected location (45%), followed by the lower leg (19%). Patellofemoral pain syndrome was the most-reported injury (20%), followed by medial tibial stress syndrome (17%). Obsessive passionate attitude (odds ratio (OR):1.35; 95% confidence interval (CI):1.18-1.54), motivation to exercise (OR:1.09; CI:1.03-1.15), and sleep quality (OR:1.23; CI:1.15-1.31) were associated with RRIs, as were perceived health (OR:0.96; CI:0.94-0.97), running over 20 km/week (OR:1.58; CI:1.04-2.42), overweight (OR:2.17; CI:1.41-3.34), pes planus (OR:1.80; CI:1.12-2.88), hard-surface running (OR:1.37; CI:1.17-1.59), running company (OR:1.65; CI:1.16-2.35), and following a training program (OR:1.51; CI:1.09-2.10). These factors together explained 30% of the variance in RRIs. A separate regression analysis showed that mental aspects and sleep quality explain 15% of the variance in RRIs. The association of mental aspects and sleep quality with RRIs adds new insights into the multifactorial etiology of RRIs. We therefore recommend that besides common risk factors for RRI, mental aspects and sleep be incorporated into the advice on prevention and management of RRIs.

[Evaluation of the efficiency of therapeutic gymnastics for knee joint injuries in athletes of the senior age groups.]

The introduction and scientific substantiation of methods for organizing sports events with optimal motor loads for citizens of middle and senior age groups should be based on two principles: general (pedagogical) principles of physical education and sports training, adapted to the specifics of health-related training; analysis of physiological and psychophysiological effects that are created by physical activity of various types and directions in the human body. The importance of this topic is due to the fact that knee injuries occupy a special place in the sports of veterans, and severe injuries and injuries in this area can restrict an athlete in his professional activities. The problem of rehabilitation of athletes of older age groups with knee injuries is not only a medical problem, but also has an important socio-economic significance. The results obtained in the work will make it possible to more objectively approach the creation and implementation of rehabilitation treatment programs without surgical interventions. Therefore, the assessment of the effectiveness of the complex of medical gymnastics for the rehabilitation and prevention of traumatic injuries of the knee joint (ICD-10: S80.83, M17.23, M94.2) in comparison with the traditionally used exercise therapy exercises for patients of older age groups on the first stage of rehabilitation treatment is an urgent task.

Temporal Kinematic Differences between Forward and Backward Jump-Landing

Backward jump-landing during sports performance will result in dynamic postural instability with a greater risk of injury, and most research studies have focused on forward landing. Differences in kinematic temporal characteristics between single-leg and double-leg backward jump-landing are seldom researched and understood. The purpose of this study was to compare and analyze lower extremity kinematic differences throughout the landing phases of forward and backward jumping using single-leg and double-leg landings (FS and BS, FD and BD). Kinematic data were collected during the landing phases of FS and BS, FD and BD in 45 participants. Through statistical parametric mapping (SPM) analysis, we found that the BS showed smaller hip and knee flexion and greater vertical ground reactive force (VGRF) than the FS during 0–37.42% (p = 0.031), 16.07–32.11% (p = 0.045), and 23.03–17.32% (p = 0.041) landing phases. The BD showed smaller hip and knee flexion than the FD during 0–20.66% (p = 0.047) and 0–100% (p < 0.001) landing phases. Most differences appeared within a time frame during the landing phase at 30–50 ms in which non-contact anterior cruciate ligament (ACL) injuries are thought to occur and are consistent with the identification of risk in biomechanical analysis. A landing strategy that consciously increases the knee and hip flexion angles during backward landing should be considered for people as a measure to avoid injury during the performance of this type of physical activity.

Costs resulting from nonprofessional soccer injuries in Switzerland: A detailed analysis

BACKGROUND

Soccer injuries constitute an important public health problem and cause a high economic burden. Nevertheless, comprehensive data regarding injury costs in nonprofessional soccer are missing. The aim of this study was to determine which groups of nonprofessional soccer athletes, injury types, and injury situations caused high injury costs.

METHODS

A cross-sectional, retrospective telephone survey was carried out with a random sample of persons who had sustained a soccer injury between July 2013 and June 2014 and who had reported this accident to the Swiss National Accident Insurance Fund (Suva). One year after the corresponding accident, every injury was linked to its costs and to the answers obtained in the interview about injury setting, injury characteristics, and injury causes. Finally, the costs of 702 injuries were analyzed.

RESULTS

The average cost of an injury in nonprofessional soccer amounted to €4030 (bias-corrected and accelerated 95% confidence interval (BCa 95%CI): 3427-4719). Persons aged 30 years and older experienced 35% of soccer injuries but accounted for 49% of all costs. A total of 58% of all costs were the result of injuries that occurred during amateur games. In particular, game injuries sustained by players in separate leagues for players aged 30+/40+ years led to high average costs of €8190 (BCa 95%CI: 5036-11,645). Knee injuries accounted for 25% of all injuries and were responsible for 53% of all costs. Although contact and foul play did not lead to above-average costs, twisting or turning situations were highly cost relevant, leading to an average sum of €7710 (BCa 95%CI: 5376-10,466) per injury.

CONCLUSION

Nonprofessional soccer players aged 30 years and older and particularly players in 30+/40+ leagues had above-average injury costs. Furthermore, the prevention of knee injuries, noncontact and nonfoul play injuries, and injuries caused by twisting and turning should be of highest priority in decreasing health care costs.

Ground Reaction Forces and Kinematics of Ski Jump Landing Using Wearable Sensors

In the past, technological issues limited research focused on ski jump landing. Today, thanks to the development of wearable sensors, it is possible to analyze the biomechanics of athletes without interfering with their movements. The aims of this study were twofold. Firstly, the quantification of the kinetic magnitude during landing is performed using wireless force insoles while 22 athletes jumped during summer training on the hill. In the second part, the insoles were combined with inertial motion units (IMUs) to determine the possible correlation between kinematics and kinetics during landing. The maximal normal ground reaction force (GRFmax) ranged between 1.1 and 5.3 body weight per foot independently when landing using the telemark or parallel leg technique. The GRFmax and impulse were correlated with flying time (p < 0.001). The hip flexions/extensions and the knee and hip rotations of the telemark front leg correlated with GRFmax (r = 0.689, p = 0.040; r = -0.670, p = 0.048; r = 0.820, p = 0.007; respectively). The force insoles and their combination with IMUs resulted in promising setups to analyze landing biomechanics and to provide in-field feedback to the athletes, being quick to place and light, without limiting movement.

Assessing the performance of motorcyclists' impact protectors in simulated ATD knee and shoulder impacts

OBJECTIVE

Fractures are a common injury among motorcycle riders and can have serious health implications. Impact protection (IP) has been designed to help prevent fractures, yet there are conflicting opinions as to whether this IP does in fact help prevent fractures in real-world crashes. This work aimed to (1) use simulated dummy impacts to examine whether existing types of IP could reduce the force transferred to the underlying bone to below fracture tolerance levels and (2) investigate whether current European Standard (EN 1621-1) test procedures for impact protectors designed for motorcyclists are sufficient to ensure fracture protection.

METHOD

Twenty-three shoulder and 7 knee IP specimens were tested using a 23-kg impactor contacting axially along the clavicle and femur of an anthropomorphic test device (ATD) at an energy level corresponding to the fracture tolerance of these bones. Sixteen IP specimens were the same as those worn by motorcycle riders involved in crashes where injury outcome was known (knee: n = 3; shoulder: n = 13) and the IP had been previously tested to EN 1621-1. Other IP tested represented a wide range of IP available for purchase at a motorcycle accessory store. Double and triple layers of IP were also tested. Energy attenuated during the dummy impacts was compared to energy attenuated when tested to EN 1621-1.

RESULTS

Of the 23 shoulder IP tested, the average percentage reduction of transferred force to the shoulder from the baseline test was 7.6 ± 4.8%. The percentage reduction of transferred force to the knee from the baseline was 43.9 ± 7.5%. The entire group of knee IP tested reduced the transferred force to the knee to below the 10-kN injury threshold for the femur. There was a positive but nonsignificant correlation between the ATD test and the EN 1621-1 impact test performance, suggesting that the European standard test method likely provides a good indication of IP performance. However, given the low correlation coefficient, the relationship between IP performance in the European standard test method and injury protection remains unclear.

CONCLUSION

Though the energy attenuation test method in the European standard may be an appropriate approach, distinct differences in injury protection performance observed between knee and shoulder IP indicate that there may be a need for different performance criteria for IP designated to protect different body regions.

The effects of a four week jump-training program on frontal plane projection angle in female gymnasts

OBJECTIVES

To investigate the effects of a four week jump training program on frontal plane projection angle (FPPA) in young female gymnasts.

DESIGN

Intervention study, consisting of a four week jump training program performed for 15 min as part of a warm-up, three days per week for four weeks.

SETTING

Gymnastics training center.

PARTICIPANTS

Fourteen youth female gymnasts (age: 13.5 ± 2.14 years, height: 1.54 ± 0.11 m, body mass: 46.23 ± 7.68 kg).

MAIN OUTCOME MEASURES

Change in FPPA during a 30 cm drop landing and tuck back somersault.

RESULTS

Large and significant decreases (p < 0.001) in FPPA of 6.8° (39%) and 8.4° (37%) during the drop landing and tuck back somersault, respectively.

CONCLUSION

The jump training program was successful in improving FPPA in female gymnasts and is advised to be implemented into the warm-ups and training programs of competitive female gymnasts to improve FPPA and therefore reduce the risk factors associated with knee injuries.

Protective Knee Braces and the Biomechanics of the Half-Squat Parachute Landing

INTRODUCTION

Knee injuries are common among paratroopers and skydivers during landing maneuvers. The aim of this study was to investigate the effects of dropping height and the use of protective knee braces on parachute landing biomechanics.

METHODS

The study cohort consisted of 30 male elite paratroopers with formal parachute landing training and more than 2 yr of parachute jumping experience. Each participant was instructed to jump off a platform at two different heights (40 and 80 cm, respectively) and land on force plates in a half-squat posture. All participants tested three different knee brace conditions (no-brace, elastic brace, and semi-rigid brace) at each height.

RESULTS

With an increase in dropping height, peak vertical ground reaction forces (GRF), peak flexion angle, peak flexion angular displacement, peak abduction angle, peak abduction angular displacement, peak extorsion angle, and peak extorsion angular displacement of the knee joint all increased. As compared without the use of a brace, use of an elastic or semi-rigid knee brace significantly reduced peak flexion angle, peak flexion angular displacement, peak abduction angular displacement, and peak extorsion angle, while there were no significant differences in peak vertical GRF or peak extorsion angular displacement. The semi-rigid brace provided the greatest restriction against peak abduction angle (3-6°).

DISCUSSION

The elastic and semi-rigid knee braces both effectively restricted motion stability of the knee joint in the sagittal and coronal planes. The semi-rigid brace had a more marked effect, although the comfort of this device should be improved.Wu D, Zheng C, Wu J, Wang L, Wei X, Wang L. Protective knee braces and the biomechanics of the half-squat parachute landing. Aerosp Med Hum Perform. 2018; 89(1):26-31.

Evidence-based concepts for prevention of knee and ACL injuries. 2017 guidelines of the ligament committee of the German Knee Society (DKG)

INTRODUCTION

Knee injuries and especially anterior cruciate ligament (ACL) tears are frequent in athletes. Therefore, primary and secondary prevention of sports-related lower limb injuries is an ongoing topic of interest. The aim of present study was to establish guidelines for the prevention of knee and ACL injuries on the basis of evidence-based concepts represented in current literature.

METHODS

A comprehensive literature review regarding prevention programs for knee and ACL injuries was conducted.

RESULTS

Several modifiable and non-modifiable risk factors for knee injuries in athletes have been reported in literature. Referring to the ACL, specific injury mechanisms have been identified and are well understood. In particular, it has been demonstrated that dynamic valgus is one of the most important modifiable risk factors. Simple tests like the drop jump test have shown their efficacy in screening and detecting athletes at risk. There is only few evidence for the preventive effect on knee and ACL injuries by single exercises. However, in order to prevent or correct endangering movement patterns including dynamic valgus, several complex prevention programs have been developed in the past. These prevention programs are included in standard warm-up exercises and are focusing on muscle strength, balance, and proprioception, as well as running and flexibility. It is reported that these training programs can reduce the incidence of knee injuries by up to 27% and ACL injuries by up to 51%.

CONCLUSIONS

Screening, identification, and correction of endangering movement patterns like the dynamic valgus are the first crucial steps in order to prevent knee and ACL injuries in athletes. Furthermore, jumping, running and flexibility exercises as well as balance and strength training are proven to reduce the incidence of these injuries and should, therefore, be integrated into the regular warm up program. Appropriate complete prevention programs are freely accessible via the Internet and should be adapted to the specific sport disciplines.

Improvement in Offaxis Neuromuscular Control Under Slippery Conditions Following Six-Week Pivoting Leg Neuromuscular Training

Knee injuries are usually associated with offaxis loadings in the transverse and frontal planes. Thus, improvement of lower limb offaxis neuromuscular control is important in knee injury prevention and post-injury rehabilitation. The goal of this paper was to investigate the effects of six-week pivoting offaxis intensity adjustable neuromuscular control training (POINT) using a custom-made offaxis elliptical trainer on lower limb offaxis neuromuscular control performance in trained and untrained functional tasks under slippery conditions. Twenty-six subjects participated in 18 sessions of POINT (three sessions per week for six weeks) and 25 subjects served as controls who did a regular workout. Offaxis neuromuscular control performance measures in terms of pivoting instability, sliding instability, and time-to-peak offaxis EMG entropy were evaluated on both groups under slippery conditions including a trained free pivoting task and untrained free sliding task and free pivoting and sliding task. Compared with the control group, the training group significantly decreased pivoting instability and the time-to-peak offaxis EMG entropy in lower limb muscles, indicating improvement in offaxis neuromuscular control performance. Furthermore, the training group showed reduced pivoting instability and sliding instability during the untrained free pivoting and sliding task. This paper may help us develop more focused and effective offaxis training programs to reduce knee injuries associated with offaxis loadings.

A Meta-Analysis to Determine if Lower Extremity Muscle Strengthening Should Be Included in Military Knee Overuse Injury-Prevention Programs

CONTEXT

 Knee overuse injuries are the most common musculoskeletal complaints in military trainees and are common in active-duty warfighters. Muscle strengthening is usually recommended; however, research is conflicting in this area, which makes it difficult to develop effective screening, prevention, and training interventions for warfighters.

OBJECTIVE

 To determine if lower extremity muscular weakness contributes to knee overuse injuries and identify specific muscular involvement.

DATA SOURCES

 We searched MEDLINE, PubMed, Web of Science, SPORTDiscus, CINAHL, and Military & Government Collection and reference lists of relevant articles published between January 1, 2000, and January 1, 2013.

STUDY SELECTION

 For inclusion, requirements were uninjured and injured groups; provision of the sample size, means, and standard deviations for all groups; identification of the specific muscles assessed; and clearly defined knee injury.

DATA EXTRACTION

 Sample size, sex, and muscle strength means and standard deviations.

DATA SYNTHESIS

 Twenty-five studies met these criteria. We used the Scottish Intercollegiate Guidelines Network algorithm to determine the appropriate tool for appraising article quality. Unweighted random-effects model meta-analyses were conducted. Separate meta-analyses were performed for the moderators of strength measurement scale (absolute or normalized muscle strength), muscle group, and sex. A weighted random-effects model with a Hedges g effect metric and 95% confidence intervals were used for comparison across studies.

CONCLUSIONS

 Our meta-analysis suggests that individuals with symptoms of a knee overuse injury have lower absolute and normalized hip muscle strength. Specifically, they had lower absolute hip external-rotator, knee-extensor, and knee-flexor strength, as well as lower normalized hip external-rotator, hip-extensor, and hip-abductor strength, compared with asymptomatic control participants. The findings suggest a possible link between lower hip and thigh strength and knee overuse injuries. Further research is needed to determine if weakness is a cause or a result of knee overuse injuries before screening and intervention can be developed for at-risk warfighters.

Injuries and injury prevention during foot marching

Since the beginning of recorded history, Soldiers have carried arms and equipment on their bodies. More recently, loads have substantially increased, driven by improvements in weapons technology and personal protection. As Soldier loads increase, there are increases in energy cost, altered gait mechanics, increased stress on the musculoskeletal system, and more rapid fatigue, factors that may increase the risk of injury. Common injuries and symptoms experienced by Soldiers on load-carriage missions include foot blisters, metatarsalgia, knee problems, and back problems. This article discusses these problems, providing diagnoses, injury mechanisms, and preventive measures. In general, lighter loads, improving load distribution, using appropriate physical training, selecting proper equipment, and using specific prevention techniques will facilitate load carriage and provide Special Operations Forces with a higher probability of mission success.

Management of knee articular cartilage injuries in athletes: chondroprotection, chondrofacilitation, and resurfacing

Articular cartilage defects of the knee are common among athletes where the physical demands of sport result in significant stresses on joints. Chondral defects are associated with pain and functional impairment that limit sporting participation and may progress to joint degeneration and frank arthritis. Management of established chondral lesions aims to allow athletes to return to high-impact sports and can be considered in terms of protection of existing cartilage, chondrofacilitation, and resurfacing. Repaired and regenerated cartilage must closely resemble and function like normal hyaline cartilage, and this ability may be the most significant factor for the return to sport. Based on our experiences and the available literature, we outline how athletes can best protect their cartilage, how physicians can facilitate intrinsic repair of established lesions, and which methods of cartilage restoration or resurfacing should be used in different situations.

LEVEL OF EVIDENCE

IV.

Anterior Cruciate Ligament Injuries in Females: Risk Factors, Prevention, and Outcome

Anterior cruciate ligament (ACL) injuries are common among all participants in sports, occurring in approximately 1 in 3,000 individuals yearly in the USA. Epidemiological studies of ACL injuries have demonstrated that females are at higher risk for injury than males. When compared to male athletes participating in the same sports, the risk of ACL injury is two to eight times greater in females.1-3 A significant research effort has been directed at identifying risk factors that may predispose females to ACL injury. Female athletes likely have an increased incidence of ACL injury due to anatomic, hormonal, biomechanical, and neuromuscular differences between the sexes. Extrinsic factors may also play a role. As the number of girls and women participating in athletics continues to increase, understanding risk factors and developing prevention strategies will have profound physical, psychological, and financial implications for female athletes and the medical system.

Proprioceptive Training and Injury Prevention in a Professional Men's Basketball Team: A Six-Year Prospective Study

Single limb stance instability is a risk factor for lower extremity injuries. Therefore, the development of proprioception may play an important role in injury prevention. This investigation considered a professional basketball team for 6 years, integrating systematic proprioceptive activity in the training routine. The purpose was to assess the effectiveness of proprioceptive training programs based on quantifiable instability, to reduce ankle sprains, knee sprains, and low back pain through developing refined and long-lasting proprioceptive control. Fifty-five subjects were studied. In the first biennium (2004-2006), the preventive program consisted of classic proprioceptive exercises. In the second biennium (2006-2008), the proprioceptive training became quantifiable and interactive by means of electronic proprioceptive stations. In the third biennium (2008-2010), the intensity and the training volume increased while the session duration became shorter. Analysis of variance was used to analyze the differences in proprioceptive control between groups, years, and bienniums. Injury rates and rate ratios of injury during practices and games were estimated. The results showed a statistically significant reduction in the occurrence of ankle sprains by 81% from the first to the third biennium (p < 0.001). Low back pain showed similar results with a reduction of 77.8% (p < 0.005). The reduction in knee sprains was 64.5% (not significant). Comparing the third biennium with the level of all new entry players, proprioceptive control improved significantly by 72.2% (p < 0.001). These findings indicate that improvements in proprioceptive control in single stance may be a key factor for an effective reduction in ankle sprains, knee sprains, and low back pain.

Kinesio taping effect on quadriceps strength and lower limb function of healthy individuals: A blinded, controlled, randomized, clinical trial

OBJECTIVES

To analyze kinesio taping (KT) effect on quadriceps strength and lower limb function over a 7-day period.

DESIGN

Blind randomized clinical trial.

SETTING

Hospital's Physical Therapy Department.

PARTICIPANTS

Sixty healthy individuals (30 men and 30 women) were randomly distributed into three groups: Control--without KT application; Placebo--placebo KT application and Experimental--A KT application designed to stimulate quadriceps femoris activity.

MAIN OUTCOME MEASURES

The quadriceps strength was measured using a manual dynamometer whereas lower limb function was assessed using the Single Hop Test for Distance. Evaluations occurred at five time-points: baseline; immediately, 3 and 5 days after KT application; and 72 h post KT withdrawal.

RESULTS

There was no significant interaction between time-points and groups for muscle strength: dominant (P = 0.13) and non-dominant (P = 0.41) and lower limb function: dominant (P = 0.09) and non-dominant (P = 0.53); but lower limb function within-group comparisons showed improvements in all groups at the evolution of all time-points analyzed for both limbs (P = 0.001). This is possibly due to a learning effect as the participants became more familiar with executing the assessment tests.

CONCLUSION

KT did not improve quadriceps strength and lower limb function of healthy individuals and its application with these objectives should be reconsidered.

Assessment of isokinetic knee strength in elite young female basketball players: correlation with vertical jump

AIM

To explore the isokinetic concentric strength of the knee muscle groups, and the relationship between the isokinetic knee extensors strength and the vertical jump performance in young elite female basketball players.

METHODS

Eighteen elite female basketball players performed a countermovement jump, and an isokinetic knee test using a Biodex dynamometer. The maximal isokinetic peak torque of the knee extensor and flexor muscles was recorded at four angular velocities (90°/s, 180°/s, 240°/s and 300°/s) for the dominant and non-dominant legs. The conventional hamstring/quadriceps ratio (H/Q) was assessed at each angular velocity for both legs.

RESULTS

There was no significant difference between dominant and non-dominant leg whatever the angular velocity (all P>0.05). However, the H/Q ratio enhanced as the velocity increased from 180°/s to 300°/s (P<0.05). Furthermore, low to high significant positive correlations were detected between the isokinetic measures of the knee extensors and the vertical jump height. The highest one was found for the knee extensors peak torque at a velocity of 240°/s (r=0.88, P<0.001).

CONCLUSION

The results accounted for an optimal velocity at which a strong relationship could be obtained between isokinetic knee extensors strength and vertical jump height. Interestingly, the H/Q ratio of the young elite female basketball players in the present study was unusual as it was close to that generally observed in regular sportsmen.

Enhanced retention of drop vertical jump landing technique: A randomized controlled trial

External focus instructions have been shown to result in superior motor performance compared to internal focus instructions. Using an EF may help to optimize current anterior cruciate ligament (ACL) injury prevention programs. The purpose of the current study was to investigate the effects of instructions on landing technique and performance by comparing an external focus (EF), internal focus (IF), video (VI) and control (CTRL) group. Subjects (age 22.50±1.62years, height 179.70±10.43cm, mass 73.98±12.68kg) were randomly assigned to IF (n=10), EF (n=10), VI (n=10) or CTRL group (n=10). Landing was assessed from a drop vertical jump (DVJ) in five sessions: pretest, two training blocks (TR1 and TR2) and directly after the training sessions (post test) and retention test 1week later. Group specific instructions were offered in TR1 and TR2. Landing technique was assessed with the Landing Error Scoring System (LESS) and jump height was taken as performance measure. The results show that males in the VI group and females both in the VI and EF groups significantly improved jump-landing technique. Retention was achieved and jump height was maintained for males in the VI group and females both in the VI and EF groups. It is therefore concluded that EF and VI instructions have great potential in ACL injury prevention.

Dynamic Neuromuscular Control of the Lower Limbs in Response to Unexpected Single-Planar versus Multi-Planar Support Perturbations in Young, Active Adults

PURPOSE

An anterior cruciate ligament (ACL) injury involves a multi-planar injury mechanism. Nevertheless, unexpected multi-planar perturbations have not been used to screen athletes in the context of ACL injury prevention yet could reveal those more at risk. The objective of this study was to compare neuromuscular responses to multi-planar (MPP) and single-planar perturbations (SPP) during a stepping-down task. These results might serve as a basis for future implementation of external perturbations in ACL injury screening programs.

METHODS

Thirteen young adults performed a single leg stepping-down task in eight conditions (four MPP and four SPP with a specified amplitude and velocity). The amplitudes of vastus lateralis (VL), vastus medialis (VM), hamstrings lateralis (HL), hamstrings medialis (HM) EMG activity, medio-lateral and anterior-posterior centre of mass (COM) displacements, the peak knee flexion and abduction angles were compared between conditions using an one-way ANOVA. Number of stepping responses were monitored during all conditions.

RESULTS

Significantly greater muscle activity levels were found in response to the more challenging MPP and SPP compared to the less challenging conditions (p < 0.05). No differences in neuromuscular activity were found between the MPP conditions and their equivalents in the SPP. Eighteen stepping responses were monitored in the SPP versus nine in the MPP indicating that the overall neuromuscular control was even more challenged during the SPP which was supported by greater COM displacements in the SPP.

CONCLUSION

The more intense MPP and SPP evoked different neuromuscular responses resulting in greater muscle activity levels compared to small perturbations. Based on the results of COM displacements and based on the amount of stepping responses, dynamic neuromuscular control of the knee joint appeared less challenged during the MPP. Therefore, future work should investigate extensively if other neuromuscular differences (i.e. co-activation patterns and kinetics) exist between MPP and SPP. In addition, future work should examine the influence on the neuromuscular control of the magnitude of the perturbations and the magnitude of stepping height and stepping distance.

Injury Risk Estimation Expertise: Cognitive-Perceptual Mechanisms of ACL-IQ

Instrument-based biomechanical movement analysis is an effective injury screening method but relies on expensive equipment and time-consuming analysis. Screening methods that rely on visual inspection and perceptual skill for prognosticating injury risk provide an alternative approach that can significantly reduce cost and time. However, substantial individual differences exist in skill when estimating injury risk performance via observation. The underlying perceptual-cognitive mechanisms of injury risk identification were explored to better understand the nature of this skill and provide a foundation for improving performance. Quantitative structural and process modeling of risk estimation indicated that superior performance was largely mediated by specific strategies and skills (e.g., irrelevant information reduction), and independent of domain-general cognitive abilities (e.g., mental rotation, general decision skill). These cognitive models suggest that injury prediction expertise (i.e., ACL-IQ) is a trainable skill, and provide a foundation for future research and applications in training, decision support, and ultimately clinical screening investigations.

Joint-position sense is altered by football pre-participation warm-up exercise and match induced fatigue

BACKGROUND

The demands to which football players are exposed during the match may augment the risk of injury by decreasing the sense of joint position. This study aimed to assess the effect of pre-participation warm-up and fatigue induced by an official football match on the knee-joint-position sense of football players.

METHODS

Fourteen semi-professional male football players (mean age: 25.9±4.6 years old) volunteered in this study. The main outcome measures were rate of perceived exertion and knee-joint-position sense assessed at rest, immediately after a standard warm-up (duration 25 min), and immediately after a competitive football match (90 minutes duration).

RESULTS

Perceived exertion increased significantly from rest to the other assessments (rest: 8.6±2.0; after warm-up: 12.1±2.1; after football match: 18.5±1.3; p<0.001). Compared to rest, absolute angular error decreased significantly after the warm-up (4.1°±2.2° vs. 2.0°±1.0°; p=0.0045). After the match, absolute angular error (8.7°±3.8°) increased significantly comparatively to both rest (p=0.001) and the end of warm-up (p<0.001). Relative error showed directional bias with an underestimation of the target position, which was higher after the football match compared to both rest (p<0.001) and after warm-up (p<0.001).

CONCLUSIONS

The results indicate that knee-joint-position sense acuity was increased by pre-participation warm-up exercise and was decreased by football match-induced fatigue.

CLINICAL RELEVANCE

Warm-up exercises could contribute to knee injury prevention, whereas the deleterious effect of match-induced fatigue on the sensorimotor system could ultimately contribute to knee instability and injury.

Reliability of 3-Dimensional Measures of Single-Leg Drop Landing Across 3 Institutions: Implications for Multicenter Research for Secondary ACL-Injury Prevention

CONTEXT

Due to the limitations of single-center studies in achieving appropriate sampling with relatively rare disorders, multicenter collaborations have been proposed to achieve desired sampling levels. However, documented reliability of biomechanical data is necessary for multicenter injury-prevention studies and is currently unavailable.

OBJECTIVE

To measure the reliability of 3-dimensional (3D) biomechanical waveforms from kinetic and kinematic variables during a single-leg landing (SLL) performed at 3 separate testing facilities.

DESIGN

Multicenter reliability study.

SETTING

3 laboratories.

PATIENTS

25 female junior varsity and varsity high school volleyball players who visited each facility over a 1-mo period.

INTERVENTION

Subjects were instrumented with 43 reflective markers to record 3D motion as they performed SLLs. During the SLL the athlete balanced on 1 leg, dropped down off of a 31-cm-high box, and landed on the same leg. Kinematic and kinetic data from both legs were processed from 2 trials across the 3 laboratories.

MAIN OUTCOME MEASURES

Coefficients of multiple correlations (CMC) were used to statistically compare each joint angle and moment waveform for the first 500 ms of landing.

RESULTS

Average CMC for lower-extremity sagittal-plane motion was excellent between laboratories (hip .98, knee .95, ankle .99). Average CMC for lower-extremity frontal-plane motion was also excellent between laboratories (hip .98, knee .80, ankle .93). Kinetic waveforms were repeatable in each plane of rotation (3-center mean CMC ≥.71), while knee sagittal-plane moments were the most consistent measure across sites (3-center mean CMC ≥.94).

CONCLUSIONS

CMC waveform comparisons were similar relative to the joint measured to previously published reports of between-sessions reliability of sagittal- and frontal-plane biomechanics performed at a single institution. Continued research is needed to further standardize technology and methods to help ensure that highly reliable results can be achieved with multicenter biomechanical screening models.

Safety assessment characteristics of pedestrian legform impactors in vehicle-front impact tests

This study investigated the characteristics of safety assessment results of front-area vehicle impact tests carried out using the Transport Research Laboratory (TRL) legform impactor and a flexible legform impactor (FLEX legform impactor). Different types of vehicles (sedan, sport utility vehicle, high-roof K-car, and light cargo van) were examined. The impact locations in the study were the center of the bumper and an extremely stiff structure of the bumper (i.e., in front of the side member) of each tested vehicle. The measured injury criteria were normalized by injury assessment reference values of each legform impactor. The test results for center and side-member impacts indicated that there were no significant differences in ligament injury assessments derived from the normalized knee ligament injury measures between the TRL legform impactor and the FLEX legform impactor. Evaluations made using the TRL legform impactor and the FLEX legform impactor are thus similar in the vehicle safety investigation for knee ligament injury. Vehicle-center impact test results revealed that the tibia fracture assessments derived from the normalized tibia fracture measures did not significantly differ between the TRL legform impactor and the FLEX legform impactor. However, for an impact against an extremely stiff structure, there was a difference in the tibia fracture assessment between the FLEX legform impactor and the TRL legform impactor owing to their different sensor types.

Dosage effects of neuromuscular training intervention to reduce anterior cruciate ligament injuries in female athletes: meta- and sub-group analyses

BACKGROUND

Although a series of meta-analyses demonstrated neuromuscular training (NMT) is an effective intervention to reduce anterior cruciate ligament (ACL) injury in female athletes, the potential existence of a dosage effect remains unknown.

OBJECTIVE

Our objective was to systematically review previously published clinical trials and evaluate potential dosage effects of NMT for ACL injury reduction in female athletes.

DESIGN

This study took the form of a meta- and sub-group analysis.

SETTING

The keywords 'knee', 'anterior cruciate ligament', 'ACL', 'prospective', 'neuromuscular', 'training', 'female', and 'prevention' were utilized in PubMed and EBSCO host for studies published between 1995 and May 2012.

PARTICIPANTS

Inclusion criteria set for studies in the current analysis were (i) recruited female athletes as subjects, (ii) documented the number of ACL injuries, (iii) employed an NMT intervention aimed to reduce ACL injuries, (iv) had a control group, (v) used a prospective control trial design, and (vi) provided NMT session duration and frequency information.

MAIN OUTCOME MEASURES

The number of ACL injuries and female athletes in each group (control and intervention) were compared based on duration, frequency, and volume of NMT via odds ratios (ORs).

RESULTS

A total of 14 studies were reviewed. Analyses that compared the number of ACL injuries with short versus long NMT duration showed greater ACL injury reduction in female athletes who were in the long NMT duration group (OR 0.35, 95% CI 0.23-0.53, p = 0.001) than in those in the short NMT duration group (OR 0.61, 95% CI 0.41-0.90, p = 0.013). Analyses that compared single versus multi NMT frequency indicated greater ACL injury reduction in multi NMT frequency (OR 0.35, 95 % CI 0.23-0.53, p = 0.001) compared with single NMT frequency (OR 0.62, 95% CI 0.41-0.94, p = 0.024). Combining the duration and frequency of NMT programs, an inverse dose-response association emerged among low (OR 0.66, 95% CI 0.43-0.99, p = 0.045), moderate (OR 0.46, 95% CI 0.21-1.03, p = 0.059), and high (OR 0.32, 95% CI 0.19-0.52, p = 0.001) NMT volume categories.

CONCLUSIONS

The inverse dose-response association observed in the subgroup analysis suggests that the higher the NMT volume, the greater the prophylactic effectiveness of the NMT program and increased benefit in ACL injury reduction among female athletes.

Seven steps for developing and implementing a preventive training program: lessons learned from JUMP-ACL and beyond

Musculoskeletal injuries during military and sport-related training are common, costly and potentially debilitating. Thus, there is a great need to develop and implement evidence-based injury prevention strategies to reduce the burden of musculoskeletal injury. The lack of attention to implementation issues is a major factor limiting the ability to successfully reduce musculoskeletal injury rates using evidence-based injury prevention programs. We propose 7 steps that can be used to facilitate successful design and implementation of evidence-based injury prevention programs within the logical constraints of a real-world setting by identifying implementation barriers and associated solutions. Incorporating these 7 steps along with other models for behavioral health interventions may improve the overall efficacy of military and sport-related injury prevention programs.

Feedback techniques to target functional deficits following anterior cruciate ligament reconstruction: implications for motor control and reduction of second injury risk

Primary anterior cruciate ligament (ACL) injury prevention training has been shown to reduce the risk of injury. Less is known about the effect of prevention on second injury after ACL reconstruction (ACLR). Given recent findings that second injury rates exceed 20 % in only the first year following the return to sport, it is imperative that rehabilitation after ACLR is scrutinized so that second injury preventative strategies can be optimized. A potential limitation of current rehabilitative processes following ACLR could be a deficiency in the transition from conscious awareness achieved during rehabilitation sessions to unexpected and automatic movements required for athletic activities on the field. Learning strategies with an internally directed focus have traditionally been utilized but may be less suitable for acquisition of control of complex motor skills required for sport reintegration. Conversely, an externally focused rehabilitation strategy may enhance skill acquisition more efficiently and increase the potential to transfer to competitive sport. This article presents new insights gained from the motor learning domain that may improve neuromuscular training programmes via increased retention from improved techniques and may ultimately reduce the incidence of second ACL injuries.

Anterior cruciate ligament injuries: diagnosis, treatment, and prevention

The number of anterior cruciate ligament (ACL) injuries reported in athletes younger than 18 years has increased over the past 2 decades. Reasons for the increasing ACL injury rate include the growing number of children and adolescents participating in organized sports, intensive sports training at an earlier age, and greater rate of diagnosis because of increased awareness and greater use of advanced medical imaging. ACL injury rates are low in young children and increase sharply during puberty, especially for girls, who have higher rates of noncontact ACL injuries than boys do in similar sports. Intrinsic risk factors for ACL injury include higher BMI, subtalar joint overpronation, generalized ligamentous laxity, and decreased neuromuscular control of knee motion. ACL injuries often require surgery and/or many months of rehabilitation and substantial time lost from school and sports participation. Unfortunately, regardless of treatment, athletes with ACL injuries are up to 10 times more likely to develop degenerative arthritis of the knee. Safe and effective surgical techniques for children and adolescents continue to evolve. Neuromuscular training can reduce risk of ACL injury in adolescent girls. This report outlines the current state of knowledge on epidemiology, diagnosis, treatment, and prevention of ACL injuries in children and adolescents.

Effects of barefoot and barefoot inspired footwear on knee and ankle loading during running

BACKGROUND

Recreational runners frequently suffer from chronic pathologies. The knee and ankle have been highlighted as common injury sites. Barefoot and barefoot inspired footwear have been cited as treatment modalities for running injuries as opposed to more conventional running shoes. This investigation examined knee and ankle loading in barefoot and barefoot inspired footwear in relation to conventional running shoes.

METHOD

Thirty recreational male runners underwent 3D running analysis at 4.0m·s(-1). Joint moments, patellofemoral contact force and pressure and Achilles tendon forces were compared between footwear.

FINDINGS

At the knee the results show that barefoot and barefoot inspired footwear were associated with significant reductions in patellofemoral kinetic parameters. The ankle kinetics indicate that barefoot and barefoot inspired footwear were associated with significant increases in Achilles tendon force compared to conventional shoes.

INTERPRETATION

Barefoot and barefoot inspired footwear may serve to reduce the incidence of knee injuries in runners although corresponding increases in Achilles tendon loading may induce an injury risk at this tendon.

Effects of knee injury primary prevention programs on anterior cruciate ligament injury rates in female athletes in different sports: a systematic review

BACKGROUND

Anterior Cruciate Ligament (ACL) injury is frequently encountered in sports.

PURPOSE

To analyze the effects of ACL injury prevention programs on injury rates in female athletes between different sports.

METHODS

A comprehensive literature search was performed in September 2012 using Pubmed Central, Science Direct, CINAHL, PEDro, Cochrane Library, SCOPUS, SPORTDiscus. The key words used were: 'anterior cruciate ligament', 'ACL', 'knee joint', 'knee injuries', 'female', 'athletes', 'neuromuscular', 'training', 'prevention'. The inclusion criteria applied were: (1) ACL injury prevention training programs for female athletes; (2) Athlete-exposure data reporting; (3) Effect of training on ACL incidence rates for female athletes.

RESULTS

13 studies met the inclusion criteria. Three training programs in soccer and one in handball led to reduced ACL injury incidence. In basketball no effective training intervention was found. In season training was more effective than preseason in ACL injury prevention. A combination of strength training, plyometrics, balance training, technique monitoring with feedback, produced the most favorable results.

CONCLUSION

Comparing the main components of ACL injury prevention programs for female athletes, some sports-dependent training specificity issues may need addressing in future studies, related primarily to the individual biomechanics of each sport but also their most effective method of delivery.

Soccer-specific warm-up and lower extremity injury rates in collegiate male soccer players

CONTEXT

A number of comprehensive injury-prevention programs have demonstrated injury risk-reduction effects but have had limited adoption across athletic settings. This may be due to program noncompliance, minimal exercise supervision, lack of exercise progression, and sport specificity. A soccer-specific program described as the F-MARC 11+ was developed by an expert group in association with the Federation Internationale de Football Association (FIFA) Medical Assessment and Research Centre (F-MARC) to require minimal equipment and implementation as part of regular soccer training. The F-MARC 11+ has been shown to reduce injury risk in youth female soccer players but has not been evaluated in an American male collegiate population.

OBJECTIVE

To investigate the effects of a soccer-specific warm-up program (F-MARC 11+) on lower extremity injury incidence in male collegiate soccer players.

DESIGN

Cohort study.

SETTING

One American collegiate soccer team followed for 2 seasons.

PATIENTS OR OTHER PARTICIPANTS

Forty-one male collegiate athletes aged 18-25 years.

INTERVENTION(S)

The F-MARC 11+ program is a comprehensive warm-up program targeting muscular strength, body kinesthetic awareness, and neuromuscular control during static and dynamic movements. Training sessions and program progression were monitored by a certified athletic trainer.

MAIN OUTCOME MEASURE(S)

Lower extremity injury risk and time lost to lower extremity injury.

RESULTS

The injury rate in the referent season was 8.1 injuries per 1000 exposures with 291 days lost and 2.2 injuries per 1000 exposures and 52 days lost in the intervention season. The intervention season had reductions in the relative risk (RR) of lower extremity injury of 72% (RR = 0.28, 95% confidence interval = 0.09, 0.85) and time lost to lower extremity injury (P < .01).

CONCLUSIONS

This F-MARC 11+ program reduced overall risk and severity of lower extremity injury compared with controls in collegiate-aged male soccer athletes.

Comparison of gluteal and hamstring activation during five commonly used plyometric exercises

BACKGROUND

Anterior cruciate ligament injuries occur frequently in athletics, and anterior cruciate ligament injury prevention programs may decrease injury risk. However, previous prevention programs that include plyometrics use a variety of exercises with little justification of exercise inclusion. Because gluteal and hamstring activation is thought to be important for preventing knee injuries, the purpose of this study was to determine which commonly used plyometric exercises produce the greatest activation of the gluteals and hamstrings.

METHODS

EMG (Electromyography) amplitudes of the hamstring and gluteal muscles during preparatory and loading phases of landing were recorded in 41 subjects during 5 commonly used plyometric exercises. Repeated measures ANOVAs (Analysis of Variance) were used on 36 subjects to examine differences in muscle activation.

FINDINGS

Differences in hamstring (P<.01) and gluteal (P<.01) activities were identified across exercises during the preparatory and landing phases. The single-leg sagittal plane hurdle hops produced the greatest gluteal and hamstring activity in both phases. The 180° jumps did not produce significantly greater gluteal or hamstring activity than any other exercise.

INTERPRETATION

Single-leg sagittal plane hurdle hops may be the most effective exercise to activate the gluteals and hamstrings and may be important to include in anterior cruciate ligament injury prevention programs, given the importance of these muscles for limiting valgus loading of the knee. Because 180° jumps do not produce greater gluteal and hamstring activation than other plyometric exercises, their removal from injury prevention programs may be warranted without affecting program efficacy.

Augmented feedback supports skill transfer and reduces high-risk injury landing mechanics: a double-blind, randomized controlled laboratory study

BACKGROUND

There is a current need to produce a simple, yet effective method for screening and targeting possible deficiencies related to increased anterior cruciate ligament (ACL) injury risk.

HYPOTHESIS

Frontal plane knee angle (FPKA) during a drop vertical jump will decrease upon implementing augmented feedback into a standardized sport training program.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-seven female participants (mean ± SD: age, 14.7 ± 1.5 years; height, 160.9 ± 6.8 cm; weight, 54.5 ± 7.2 kg) were trained over 8 weeks. During each session, each participant received standardized training consisting of strength training, plyometrics, and conditioning. They were also videotaped running on a treadmill at a standardized speed and performing a repeated tuck jump for 10 seconds. Study participants were randomized into 2 groups and received augmented feedback on either their jumping (AF) or sprinting (CTRL) form. Average (mean of 3 trials) and most extreme (trial with greatest knee abduction) FPKA were calculated from 2-dimensional video captured during performance of the drop vertical jump.

RESULTS

After testing, a main effect of time was noted, with the AF group reducing their FPKA average by 37.9% over the 3 trials while the CTRL group demonstrated a 26.7% reduction average across the 3 trials (P < .05). Conversely, in the most extreme drop vertical jump trial, a significant time-by-group interaction was noted (P < .05). The AF group reduced their most extreme FPKA by 6.9° (pretest, 18.4° ± 12.3°; posttest, 11.4° ± 10.1°) on their right leg and 6.5° (pretest, 16.3° ± 14.5°; posttest, 9.8° ± 10.7°) on their left leg, which represented a 37.7% and 40.1% reduction in FPKA, respectively. In the CTRL group, no similar changes were noted in the right (pretest, 16.9° ± 14.3°; posttest, 14.0° ± 12.3°) or left leg (pretest, 9.8° ± 11.1°; posttest, 7.2° ± 9.2°) after training.

CONCLUSION

Providing athletes with augmented feedback on deficits identified by the tuck jump assessment has a positive effect on their biomechanics during a different drop vertical jump task that is related to increased ACL injury risk. The ability of the augmented feedback to support the transfer of skills and injury risk factor reductions across different tasks provides exciting new evidence related to how neuromuscular training may ultimately cross over into retained biomechanics that reduce ACL injuries during sport.

CLINICAL RELEVANCE

The tuck jump assessment's ease of use makes it a timely and economically favorable method to support ACL prevention strategies in young girls.