Epidemiology of Quadriceps Strains in National Collegiate Athletic Association Athletes, 2009-2010 Through 2014-2015

Intra-rater and Inter-rater Reliability of the KangaTech (KT360) Fixed Frame Dynamometry System During Maximal Isometric Strength Measurements of the Knee Flexors

Background

Fixed-frame dynamometry systems are used worldwide to assess isometric strength in both general and athletic populations. There is currently a paucity of published work where reliability estimates for fixed-frame dynamometry systems have been estimated. The aim of this study was to determine the inter-and intra-rater reliability of the KangaTech (KT360) fixed frame dynamometry system when measuring maximal isometric strength of the knee flexor muscles.

Study Design

Inter and intra-rater reliability single cohort study.

Methods

Twenty healthy university-level athletes (age= 21.65 ± 3 years, weight= 74.465 ± 30kg, height= 170.1 ± 7.0cm) took part in two testing sessions where two raters collected data during a 90° hip and knee flexion protocol. Participants performed each test twice, building to a maximal isometric contraction holding over a 5 second period with 30 second rest between sets. Data were checked for normality using a Shapiro-Wilk test. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC) were calculated. Finally, a Bland-Altman analysis was used to determine the levels of agreement for intra-and inter-rater measurements.

Results

High levels of agreement were demonstrated between left and right knee flexion as 95% of the differences were less than two standard deviations away from the mean. 'Almost perfect' intraclass correlation coefficient (ICC) values were demonstrated (Knee flexion: Inter-rater: Left, 0.99; Right, 0.99; Intra-rater: Left, 0.99; Right:0.99). Standard error of measurement (SEM) for inter-and intra-rater strength ranged from 0.26-0.69 kg, SEM% ranged from 1.34-2.71% and minimal detectable change (MDC) ranged from 1.14-2.31kg.

Conclusion

Overall, high level of inter-and intra-rater reliability were demonstrated when testing maximal isometric knee flexion. Therefore, the KT360 fixed frame dynamometry system may be considered a viable tool for measuring maximal isometric contraction of the knee flexors when repeat measures are required in clinical settings.

Level of Evidence

3b.

Guide to Muscular Injuries and Common Ligamentous Injuries Among Soccer Players

With over 250 million players worldwide, soccer is the most popular sport in the world. The overall number of players at professional, amateur, and recreational levels has increased along with an increase in player diversity, including age and sex. These increases in player numbers, as well as a variety of demographics, have resulted in an increase in soccer-related injuries. Injury in the professional setting can lead to time off the field and an effect on team results and earnings. Injury at the amateur and recreational levels can lead to time off work, away from other activities, and change in activities of daily living. We provide an extensive list of common injuries sustained by soccer players, their pathophysiology, diagnosis, treatment, and general guidelines on return to play.

Differences in Injury Profiles Between Female and Male Athletes Across the Participant Classification Framework: A Systematic Review and Meta-Analysis

BACKGROUND

Female sex is a significant determinant of anterior cruciate ligament (ACL) injury. It is not understood if sex is a key determinant of other sports-related injuries.

OBJECTIVE

The aim of this systematic review was to identify where differences in injury profiles are most apparent between the sexes in all sports across the six-tiered participant classification framework.

METHODS

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and the 'implementing PRISMA in Exercise, Rehabilitation, Sport medicine and SporTs science'(PERSiST) guidance. The databases PubMed, CINAHL, Web of Science, SPORTDiscus, Medline, Scopus, Cochrane Library and EBSCO were searched from database inception to 24 April 2023. Longitudinal, prospective and retrospective cohort studies and cross-sectional and descriptive epidemiology studies that used standard injury data collection were included. Studies were excluded if injuries were not medically diagnosed and if injuries were not reported and/or analysed by sex. Two reviewers independently extracted data and assessed study quality using the Downs and Black checklist.

RESULTS

Overall, 180 studies were included (8 tier-5, 40 tier-4, 98 tier-3, 30 tier-2, 5 tier-1 studies; one study included data in two tiers). Of those, 174 studies were of moderate quality and six studies were of limited quality. In sex-comparable sports, there was moderate evidence that female athletes had greater risk of knee injury (relative risk (RR) 2.7; 95% CI 1.4-5.5), foot/ankle injuries (RR 1.25; 95% CI 1.17-1.34), bone stress injury (RR 3.4; 95% CI 2.1-5.4) and concussion (RR 8.46; 95% CI 1.04-68.77) than male athletes. Male athletes were at increased risk of hip/groin injuries (RR 2.26; 95% CI 1.31-3.88) and hamstring injuries (RR 2.4; 95% CI 1.8-3.2) compared with females, particularly in dynamic sports. Male athletes were 1.8 (1.37-2.7) to 2.8 (2.45-3.24) times more likely to sustain acute fractures than female athletes, with the highest risk in competition.

DISCUSSION

Most studies in all cohorts were of moderate quality (mean/range of scores tier-5: 17 ± 2.2 [14-20], tier-4: 16.9 ± 1.9 [11-21], tier-3: 16.9 ± 1.5 [11-20], tier-2: 16.3 ± 2.2 [11-20], tier-1 studies: 15.6 ± 1.3 [14-17] out of 28 on the Downs and Black checklist), with only six studies of limited quality. Female athletes' propensity for bone stress injuries highlights opportunities to reinforce development of optimal bone health during adolescence and to outline the effects of energy availability. Earlier strength development and exposure to neuromuscular training programmes and modification of skill development in female athletes may be effective strategies for reducing lower limb injury risk. Key components of neuromuscular training programmes could be beneficial for reducing hip/groin and hamstring injury risk in male athletes. There may be a need for sex-specific prevention and return-to-sport protocols for sports-related concussion in female athletes.

CONCLUSIONS

Female sex was a key determinant of sports-related injuries beyond ACL injury including foot/ankle injury, bone stress injury and sports-related concussion. Male sex was a key determinant of hip/groin, hamstring injury and upper limb injury.

TRIAL REGISTRY

PROSPERO registration number: CRD42017058806 (last updated on 7th June 2023).

Oral Contraception Use and Musculotendinous Injury in Young Female Patients: A Database Study

PURPOSE

The purpose of this study is to characterize the effect of sex and the influence of oral contraception usage on musculotendinous injury (MTI). Current literature suggests a disparity in the incidence of MTI between males and females. This may be attributed to inherent biological differences between the sexes, such as in the sex hormonal milieu. There is a lack of information associating sex hormone milieu and MTI.

METHODS

We searched the PearlDiver database (a for-fee healthcare database) for males, females taking oral contraceptives (OC), and eumenorrheic females not taking any form of hormonal contraceptives (non-OC) 18-39 yr old. The three populations were matched by age and body mass index. We queried the database for lower-extremity skeletal MTI diagnoses in these groups.

RESULTS

Each group contained 42,267 patients with orthopedic injuries. There were a total of 1476 (3.49%) skeletal MTI in the male group, 1078 (2.55%) in non-OC females, and 231 (0.55%) in OC females. Both the non-OC and the OC groups had a significantly smaller proportion of MTI than males ( P < 0.0001), and therefore these groups were less likely (adjusted odds ratios, 0.72 and 0.15, respectively) to experience MTI when controlled for potential covariates.

CONCLUSIONS

In this study, we show that females are less likely to develop MTI to total injuries, when compared with males, with OC using females being least likely followed by non-OC females. These results are consistent with other epidemiological studies; however, overall results in the literature are variable. This study adds to the emerging body of literature on sex hormone-influenced musculoskeletal injury but, more specifically, MTI, which have not been rigorously investigated.

Traumatic muscle injury

Traumatic muscle injury represents a collection of skeletal muscle pathologies caused by trauma to the muscle tissue and is defined as damage to the muscle tissue that can result in a functional deficit. Traumatic muscle injury can affect people across the lifespan and can result from high stresses and strains to skeletal muscle tissue, often due to muscle activation while the muscle is lengthening, resulting in indirect and non-contact muscle injuries (strains or ruptures), or from external impact, resulting in direct muscle injuries (contusion or laceration). At a microscopic level, muscle fibres can repair focal damage but must be completely regenerated after full myofibre necrosis. The diagnosis of muscle injury is based on patient history and physical examination. Imaging may be indicated to eliminate differential diagnoses. The management of muscle injury has changed within the past 5 years from initial rest, immobilization and (over)protection to early activation and progressive loading using an active approach. One challenge of muscle injury management is that numerous medical treatment options, such as medications and injections, are often used or proposed to try to accelerate muscle recovery despite very limited efficacy evidence. Another challenge is the prevention of muscle injury owing to the multifactorial and complex nature of this injury.

Indirect Rectus Femoris Injury Mechanisms in Professional Soccer Players: Video Analysis and Magnetic Resonance Imaging Findings

OBJECTIVE

To describe injury mechanisms and magnetic resonance imaging (MRI) findings in acute rectus femoris (RF) injuries of soccer players using a systematic video analysis.

DESIGN

Descriptive case series study of consecutive RF injuries from November 2017 to July 2022.

SETTING

Two specialized sports medicine hospitals.

PARTICIPANTS

Professional male soccer players aged between 18 and 40 years, referred for injury assessment within 7 days after a RF injury, with an available video footage of the injury and a positive finding on an MRI.

INDEPENDENT VARIABLES

Rectus femoris injury mechanisms (specific scoring based on standardized models) in relation to RF muscle injury MRI findings.

MAIN OUTCOME MEASURES

Rectus femoris injury mechanism (playing situation, player/opponent behavior, movement, and biomechanics), location of injury in MRI.

RESULTS

Twenty videos of RF injuries in 19 professional male soccer players were analyzed. Three different injury mechanisms were seen: kicking (80%), sprinting (10%), and change of direction (10%). Isolated single-tendon injuries were found in 60% of the injuries. Of the kicking injuries, 62.5% included complete tendon ruptures, whereas both running injuries and none of the change of direction injuries were complete ruptures. The direct tendon was involved in 33% of the isolated injuries, and the common tendon was affected in all combined injuries.

CONCLUSIONS

Rectus femoris injuries typically occur during kicking among football players. Most of the RF injuries involve a complete rupture of at least one tendon. Kicking injuries can also affect the supporting leg, and sprinting can cause a complete tendon rupture, whereas change of direction seems not to lead to complete ruptures.

Hip Pain in an Athlete

ABSTRACT

Hip pain is a common complaint in sports, and narrowing the differential diagnosis can be difficult. Many etiologies are secondary to overuse and respond well to nonsurgical treatment. The increased use of point-of-care ultrasound has helped provide timely and accurate diagnoses and some guided treatments. The hip is in close proximity to the abdomen and pelvis, and clinicians should be familiar with nonmusculoskeletal pain generators. This article is a comprehensive review of hip pain etiologies in athletes.

Epidemiology of Hand and Wrist Injuries in Collegiate-Level Athletes in the United States

PURPOSE

Hand and wrist injuries are common among competitive athletes and can have a substantial impact on playing time and future participation. The purpose of this study was to provide epidemiological data from the National Collegiate Athletic Association Injury Surveillance Program to correlate injury diagnosis with the need for surgery and time loss.

METHODS

Using the National Collegiate Athletic Association Injury Surveillance Program, this retrospective study extracted data of hand and wrist injuries for all 25 National Collegiate Athletic Association sports from the academic years 2004-2005 to 2013-2014. The "severe" category was defined as injuries resulting in the following: (1) surgery, (2) season-ending status, or (3) more than 30 days of playing time loss. The epidemiologic data included injury rate per 100,000 athlete exposures (defined as 1 athlete participating in 1 practice or competition) based on diagnoses and demographic information such as sports and sex. We used a Poisson regression model to estimate the incidence rate and 95% confidence interval.

RESULTS

Overall, 4,851 hand injuries were identified, with an injury rate of 41.2 per 100,000 athlete exposures. The most common diagnoses were metacarpal or phalangeal fractures (19.9%), lacerations or contusions (15.4%), and wrist sprains (14.7%). The surgical rate was 9.6%, and the season-ending rate was 5.8%. Severe injuries occurred in 17.5% of the hand and wrist injuries; within this subset, the most common diagnoses included metacarpal or phalangeal fractures (43.8%), scaphoid fractures (12.8%), and thumb ulnar collateral ligament tears (8.7%). Scaphoid fractures and metacarpal or phalangeal fractures had the highest surgical rate and season-ending rate among all the injuries.

CONCLUSIONS

The injury rate of hand and wrist injuries is comparable with those of other common sports injuries. Approximately one fifth of the injuries were considered severe, which led to a high surgical rate, and these had a considerable impact on the athletes' ability to finish the season.

TYPE OF STUDY/LEVEL OF EVIDENCE

Outcome research level II.

Isolated, Full-Thickness Proximal Rectus Femoris Injury in Competitive Athletes: A Systematic Review of Injury Characteristics and Return to Play

Background

Characteristics regarding mechanism of injury, management, and return-to-play (RTP) rate and timing are important when treating and counseling athletes with rectus femoris tears.

Purpose

To systematically review the literature to better understand the prevalence, sporting activity, injury mechanisms, and treatment of patients with rectus femoris injury and to provide prognostic information regarding the rate and timing of RTP.

Study Design

Systematic review; Level of evidence, 4.

Methods

Following the 2020 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we queried PubMed/MEDLINE, Cochrane, OVID, EMBASE, and Google Scholar in March 2022 for studies reporting on athletes sustaining isolated, full-thickness tearing, or bony avulsion injuries to the proximal rectus femoris during sporting activity. Excluded were studies without evidence of full-thickness tearing or avulsion, with athletes sustaining concomitant injuries, or with injuries occurring from nonsporting activities. The percentage of athletes sustaining injuries was calculated based on sport, injury mechanism, and management (nonoperative versus operative).

Results

Of 132 studies initially identified, 18 were included, comprising 132 athletes (mean age, 24.0 ± 5.4 years; range, 12-43 years). The most common sporting activities were soccer (70.5%) and rugby (15.2%). The most reported mechanisms of injury were kicking (47.6%) and excessive knee flexion/forced hip extension (42.9%). Avulsion injuries were reported in 86% (n = 114) of athletes. Nonoperative management was reported in 19.7% of athletes, with operative management performed in 80.3%. The mean follow-up time was 21.4 ± 11.4 months (range, 1.5-48 months). The RTP rate was 93.3% (n = 14) in nonoperatively treated and 100% (n = 106) in operatively treated athletes, and the mean RTP time was 11.7 weeks (range, 5.5-15.2 weeks) in nonoperatively treated and 22.1 weeks (range, 14.0-37.6 weeks) in operatively treated athletes. Complications were reported in 7.7% (2/26) of nonoperatively treated and 18% (n = 19/106) of operatively treated athletes.

Conclusion

Full-thickness proximal rectus femoris injuries occurred most frequently in athletes participating in soccer and rugby secondary to explosive, eccentric contractions involved in kicking and sprinting. Operative management was performed in the majority of cases. Athletes who underwent operative repair had a 100% RTP rate versus 93.3% in athletes treated nonoperatively.

Association Between Injury Mechanisms and Magnetic Resonance Imaging Findings in Rectus Femoris Injuries in 105 Professional Football Players

OBJECTIVE

To describe the injury mechanism and its association with magnetic resonance imaging (MRI) injury findings in acute rectus femoris injuries.

DESIGN

Combined retrospective and prospective descriptive injury study. Retrospective cohort from January 2010 to October 2013 and prospective cohort from October 2013 to January 2019.

SETTING

Specialized sports medicine hospital.

PARTICIPANTS

Male professional football players older than 18 years playing in a national football league, referred for injury assessment within 7 days after an acute rectus femoris injury, with a positive finding on MRI.

INDEPENDENT VARIABLES

Rectus femoris muscle injury MRI findings in relation to injury mechanism in male football players.

MAIN OUTCOME MEASURES

Rectus femoris injury mechanism (kicking, sprinting, and others), MRI injury location, and grade.

RESULTS

There were 105 injuries in total, with 60 (57.1%) and 45 (42.8%) injuries from the retrospective and prospective cohorts, respectively. Kicking was the injury mechanism in 57 (54.3%) of all acute rectus femoris injuries, sprinting represented 32 (30.4%), and 16 (15.2%) were classified as others. There were 20 (19.05%) free tendon, 67 (63.8%) myotendinous junction and/or intramuscular tendon, and 18 (17.1%) peripheral myofascial located injuries. All free tendon injuries were related to kicking and graded as a complete tear of at least one of the tendons in 15/20 (75.0%) cases.

CONCLUSIONS

Kicking seems to be an important mechanism related to complete ruptures and injuries occurring at the proximal free tendon. Sprinting was the other most common mechanism but was never associated with injury to the proximal free tendon.

Time to return to full training and recurrence of rectus femoris injuries in elite track and field athletes 2010-2019; a 9-year study using the British Athletics Muscle Injury Classification

Rectus femoris (RF) injuries are common in sports requiring maximal acceleration and sprinting. The British Athletics Muscle Injury Classification (BAMIC) describes acute muscle injury based on the anatomical site of injury and has been associated with return to play in hamstring and calf muscle injury. The aim of this study was to describe and compare the time to return to full training (TRFT) and injury recurrence for BAMIC-classified RF injuries sustained by elite track and field (T&F) athletes over a 9-year period. All rectus femoris injuries sustained by elite T&F athletes on the British Athletics World Class Program between September 2010 and September 2019 that were investigated with an MRI within 7 days of acute onset anterior thigh pain were included. Injuries were graded from the MRI by a specialist musculoskeletal radiologist using the BAMIC, and TRFT and injury recurrence were determined by evaluation of the Electronic Medical Record. Athlete demographics and World Athletics event discipline were recorded. Specific injury details including mechanism, location of injury, and whether surgical or rehabilitation management was undertaken were recorded. There were 38 RF injuries in 27 athletes (24.7 ± 2.3 years; 10 male, 17 female). Average TRFT for rehabilitation managed cases was 20.4 ± 14.8 days. Grade 1 injuries had significantly shorter TRFT compared with grades 2 (p = 0.04) and 3 (p = 0.01). Intratendinous (c) and surgically managed RF injuries each had significantly longer TRFT compared with other injury classes (p < 0.001). Myofascial (a) injuries had reduced repeat injury rates compared with b or c classes (p = 0.048). Grade 3 injuries had an increased repeat injury rate compared with other grades (p = 0.02). There were 4 complete (4c) proximal free tendon injuries sustained during sprinting and all in female athletes. The average TRFT for RF injuries in elite T&F is similar to that previously identified in elite football and Australian Rules. Similar to previous research in hamstring and calf injury, RF injuries extending into the tendon (BAMIC class c) had delayed TRFT which may reflect the longer duration required for tendon healing and adaptation. Grade 3 injuries had in increased repeat injury rate compared with grades 1 and 2. The BAMIC diagnostic framework may provide useful information for clinicians managing rectus femoris injuries in T&F.

Risk Factors for Quadriceps Muscle Strain Injuries in Sport: A Systematic Review

OBJECTIVE

To identify risk factors for quadriceps muscle strain injury in sport.

DESIGN

Risk factor systematic review.

LITERATURE SEARCH

A systematic search was conducted in the MEDLINECINAHL, Embase, AMED, AUSPORT, SPORTDiscus, PEDro, and Cochrane Library databases (from inception to September 2021).

STUDY SELECTION CRITERIA

Studies reporting prospective data to evaluate risk factors related to index and/or recurrent quadriceps muscle strain injury.

DATA SYNTHESIS

A risk-of-bias assessment (using a modified Quality in Prognosis Studies tool) was performed, and we used best-evidence synthesis to qualitatively synthesize the data to quantify relationships between risk factors and quadriceps muscle injury.

RESULTS

Sixteen studies were included, capturing 2408 quadriceps injuries in 11 719 athletes. Meta-analyses were not performed due to clinical heterogeneity. The dominant kicking leg (over 3154 individuals, 1055 injuries), a previous history of quadriceps muscle injury (6208 individuals, 975 injuries), and a recent history of hamstring strain (4087 individuals, 581 injuries) were intrinsic factors associated with quadriceps injury. Extrinsic factors relating to the preseason period and competitive match play increased quadriceps injury risk; participating at higher levels of competition decreased quadriceps injury risk. Age, weight, and flexibility (intrinsic factors) had no association with quadriceps injury.

CONCLUSION

Previous quadriceps injury, recent hamstring injury, the dominant kicking leg, and competitive match play were the strongest risk factors for future quadriceps muscle injury in sport. J Orthop Sports Phys Ther 2022;52(6):389-400. doi:10.2519/jospt.2022.10870.

Sex-related Anthropometrics in a Lower-Body Mobility Assessment Among Professional Soccer Athletes

Background

The functional movement screen (FMS™) and Y-balance test (YBT) are commonly used to evaluate mobility in athletes.

Purpose

The primary aim of this investigation was to determine the relationship between demographic and anthropometric factors such as sex, body composition, and skeletal dimension and scoring on YBT and FMS™ in male and female professional soccer athletes.

Study Design

Cross Sectional.

Methods

During pre-season assessments, athletes from two professional soccer clubs were recruited and underwent body composition and skeletal dimension analysis via dual-energy X-ray absorptiometry (DEXA) scans. Balance and mobility were assessed using the YBT and FMS™. A two-tailed t-test was used to compare YBT between sexes. Chi-square was used for sex comparisons of FMS™ scores. Correlation analysis was used to determine if body composition and/or skeletal dimensions correlated with YBT or FMS™ measures. Type-I error; α=0.05.

Results

40 Participants were successfully recruited: (24 males: 27±5yr, 79±9kg; |16 females: 25±3yr, 63±4kg). YBT: Correlations were found between anterior reach and height (r=-0.36), total lean mass (LM)(r=-0.39), and trunk LM(r=-0.39) as well as between posterolateral reach and pelvic width (PW)(r=0.42), femur length (r=0.44), and tibia length (r=0.51)(all p<0.05). FMS™: The deep squat score was correlated with height(r=-0.40), PW(r=0.40), LM(r=-0.43), and trunk LM (r =-0.40)(p<0.05). Inline lunge scores were correlated with height(r=-0.63), PW(r=0.60), LM(r=-0.77), trunk LM(r=-0.73), and leg LM(r=0.70)(all p<0.05). Straight leg raise scores were correlated with PW (r=0.45, p<0.05). Females scored higher for the three lower body FMS™ measures where correlations were observed (p<0.05).

Conclusions

Lower body FMS™ scores differ between male and female professional soccer athletes and are related to anthropometric factors that may influence screening and outcomes for the FMS™ and YBT, respectively. Thus, these anatomical factors likely need to be taken into account when assessing baseline performance and risk of injury to improve screening efficacy.

Level of Evidence

Level 3b.

Imaging Review of Hockey-related Lower Extremity Injuries

Hockey is a fast-paced contact sport with a high incidence of injuries. Although injuries are more frequent among elite players, recreational hockey injuries are a common issue faced by primary care and emergency physicians. Lower extremity injuries in hockey are particularly important because they account for approximately a third of all injuries and > 60% of all overuse injuries. This pictorial review provides the general and specialty trained radiologist with a knowledge of the patterns of lower extremity injury that occur in ice hockey.

Female Athlete Hip Injuries: A Narrative Review

OBJECTIVE

In this narrative review, we highlight sex-specific anatomic and biomechanical features of the hip region in female athletes, as well as the potential impact of these characteristics on observed disparities in both intra-articular and extra-articular injury patterns between female and male athletes. It is our goal to broaden the scope of knowledge related to hip pathology in active female athletes among sports medicine providers with the hope of better optimizing sport participation and performance in female athletes.

DATA SOURCES

A literature review was conducted using PubMed database and Google Scholar search engine. Search terms included sport, female, athlete, sex differences, injury, hip, and all diagnoses discussed in this review. Cross-reference of these articles identified additional resources.

MAIN RESULTS

Sex-specific differences in both static design and dynamic function contribute to disparities in hip injury patterns between female and male athletes. Intra-articular injuries, including labral and ligamentum teres pathology, as well as extra-articular injuries, including iliopsoas tendon dysfunction, gluteal and proximal hamstring tendinopathy, ischiofemoral impingement, bone stress injuries, and certain nerve entrapment syndromes, seem to affect female athletes more commonly than male counterparts.

CONCLUSIONS

Given unique anatomic and functional considerations, the growing population of female athletes worldwide warrants specialized care and consideration. Potential predisposition to specific hip injuries should be taken into consideration during diagnostic evaluation of hip pain in the female athlete.

Epidemiology of Severe Foot Injuries in US Collegiate Athletes

Background

The effects of foot injuries on collegiate athletes in the United States are of interest because of the short 5-year eligibility period in the National Collegiate Athletic Association (NCAA).

Purpose

To discuss the epidemiology of severe NCAA foot injuries sustained over 10 years in 25 sports.

Study Design

Descriptive epidemiology study.

Methods

We utilized the NCAA Injury Surveillance System, which prospectively collects deidentified injury data for collegiate athletes. Severe injuries were classified as season- or career-ending injuries, injuries with >30-day time loss, or injuries requiring operative treatment. Injury rates (IRs) were analyzed per 100,000 athlete-exposures.

Results

Of 3607 total foot injuries, 18.71% (n = 675) were classified as severe, with an IR of 5.73 per 100,000 athletic-exposures. For all severe injuries, the operative rate was 24.3%, the season-ending rate 37.0%, and the career-ending rate 4.4%. The proportion of recurrent injuries was 13.9%. Men's sports with the highest severe foot IRs were basketball (IR = 10.71), indoor track (IR = 7.16), and football (IR = 7.08). Women's sports with the highest severe foot IRs were cross-country (IR = 17.15), gymnastics (IR = 14.76), and outdoor track (IR = 14.65). Among all severe foot injuries, the most common was a fifth metatarsal fracture. The highest contact/noncontact injury ratios were phalangeal fracture, turf toe, and Lisfranc injury. The severe injuries with the highest operative rates were Lisfranc injuries, fifth metatarsal fractures, and midfoot fractures. The severe injuries associated with the highest season-ending IRs were Lisfranc injury, midfoot fracture, and general metatarsal fractures. Severe flexor/extensor injuries had the highest career-ending IRs, followed by turf toe. Severe injuries with the highest median time loss were sesamoidal fractures, calcaneal fractures, and plantar fascial injuries.

Conclusion

Of all collegiate foot injuries sustained over a 10-year period, 18.7% were characterized as severe, and 24.3% of severe injuries required surgery. Basketball was the men's sport with the highest severe IR, and cross-country was the women's sport with the highest severe IR. Overall, female athletes experienced slightly higher severe foot IRs as compared with male athletes.

Fifteen-week window for recurrent muscle strains in football: a prospective cohort of 3600 muscle strains over 23 years in professional Australian rules football

OBJECTIVES

To determine the rates of muscle strain injury recurrence over time after return to play in Australian football and to quantify risk factors.

METHODS

We analysed Australian Football League player data from 1992 to 2014 for rates of the four major muscle strain injury types (hamstring, quadriceps, calf and groin) diagnosed by team health professionals. Covariates for analysis were: recent history (≤8 weeks) of each of the four muscle strains; non-recent history (>8 weeks) of each; history of hip, knee anterior cruciate ligament, knee cartilage, ankle sprain, concussion or lumbar injury; age; indigenous race; match level and whether a substitute rule was in place.

RESULTS

3647 (1932 hamstring, 418 quadriceps, 458 calf and 839 groin) muscle strain injuries occurred in 272 759 player matches. For all muscle strains combined, the risk of injury recurrence gradually reduced, with recurrence risks of 9% (hamstring), 5% (quadriceps), 2% (calf) and 6% (groin) in the first match back and remaining elevated for 15 weeks after return to play. The strongest risk factor for each muscle injury type was a recent history of the same injury (hamstring: adjusted OR 13.1, 95% CI 11.5 to 14.9; calf OR 13.3, 95% CI 9.6 to 18.4; quadriceps: OR 25.2, 95% CI 18.8 to 33.8; groin OR 20.6, 95% CI 17.0 to 25.0), followed by non-recent history of the same injury (hamstring: adjusted OR 3.5, 95% CI 3.2 to 3.9; calf OR 4.4, 95% CI 3.6 to 5.4; quadriceps OR 5.2, 95% CI 4.2 to 6.4; groin OR 3.5, 95% CI 3.0 to 4.0). Age was an independent risk factor for calf muscle strains (adjusted OR 1.6, 95% CI 1.3 to 2.0). Recent hamstring injury increased the risk of subsequent quadriceps (adjusted OR 1.8, 95% CI 1.2 to 2.7) and calf strains (OR 1.8, 95% CI 1.2 to 2.6). During the 'substitute rule' era (2011-2014), hamstring (adjusted OR 0.76, 95% CI 0.67 to 0.86), groin (OR 0.78, 95% CI 0.65 to 0.93) and quadriceps (OR 0.70, 95% CI 0.53 to 0.92) strains were less likely than outside of that era but calf (OR 1.6, 95% CI 1.3 to 1.9) strains were more likely than before the substitute rule era.

CONCLUSION

Recent injury is the greatest risk factor for the four major muscle strains, with increased risk persisting for 15 weeks after return to play.

Changes in lumbar kinematics and trunk muscle electromyographic activity during baseball batting under psychological pressure

Psychological pressure during sports competition disturbs the ideal physical movement and causes injury. Baseball batting frequently causes trunk injuries. This study aimed to examine the influence of psychological pressure on the lumbar kinematics and trunk muscle activity during the baseball batting. Fourteen collegiate baseball players participated in this study. The participants performed bat swings under three different psychological conditions (non-pressure, pressure, and emphasized pressure). The lumbar kinematics and trunk muscle activity were measured during each bat swing. One- and two-way analyses of variance were performed to compare the lumbar kinematics and trunk muscle activity among different psychological pressure conditions. The lumbar flexion angle throughout the bat swing in the swing phase, from the moment of ground contact of the lead foot to the moment of ball contact, was significantly larger under the pressure and emphasized pressure conditions than under the non-pressure condition (P<0.05). The bilateral lumbar erector spinae (LES) activities in the swing and follow-through phases were significantly higher under the emphasized pressure condition than under the non-pressure condition (P<0.05). These results indicate that the baseball batting under psychological pressure influenced the lumbar kinematics and bilateral LES activities and may be related to the development of low back pain.

Incidence of Lower Extremity Injury in the National Football League: 2015 to 2018

BACKGROUND

Lower extremity injuries are the most common injuries in professional sports and carry a high burden to players and teams in the National Football League (NFL). Injury prevention strategies can be refined by a foundational understanding of the occurrence and effect of these injuries on NFL players.

PURPOSE

To determine the incidence of specific lower extremity injuries sustained by NFL players across 4 NFL seasons.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

This retrospective, observational study included all time-loss lower extremity injuries that occurred during football-related activities during the 2015 through 2018 seasons. Injury data were collected prospectively through a leaguewide electronic health record (EHR) system and linked with NFL game statistics and player participation to calculate injury incidence per season and per 10,000 player-plays for lower extremity injuries overall and for specific injuries. Days lost due to injury were estimated through 2018 for injuries occurring in the 2015 to 2017 seasons.

RESULTS

An average of 2006 time-loss lower extremity injuries were reported each season over this 4-year study, representing a 1-season risk of 41% for an NFL player. Incidence was stable from 2015 to 2018, with an estimated total missed time burden each NFL season of approximately 56,700 player-days lost. Most (58.7%) of these injuries occurred during games, with an overall higher rate of injuries observed in preseason compared with regular season (11.5 vs 9.4 injuries per 10,000 player-plays in games). The knee was the most commonly injured lower extremity region (29.3% of lower body injuries), followed by the ankle (22.4%), thigh (17.2%), and foot (9.1%). Hamstring strains were the most common lower extremity injury, followed by lateral ankle sprains, adductor strains, high ankle sprains, and medial collateral ligament tears.

CONCLUSION

Lower extremity injuries affect a high number of NFL players, and the incidence did not decrease over the 4 seasons studied. Prevention and rehabilitation protocols for these injuries should continue to be prioritized.

Nontraumatic Anterior Thigh Pain in a NCAA Lacrosse Athlete: A Case Report and Description of a Rectus Femoris Degloving Injury

A 21-year-old female lacrosse player complained of anterior thigh pain with no known mechanism of injury and failed to improve with conservative therapy. An MRI was obtained showing a closed degloving injury of the rectus femoris, an injury only previously reported in a small case series of soccer players. After a brief period of rest, she was progressed conservatively through therapy and did well, with progression back to the level of competition at 56 days. This case highlights a rare injury not previously described in sports outside of soccer and is the first case described in a female athlete. In addition, the discussion of this case focuses on the unique anatomy of the rectus femoris.

Lumbar Spine Injuries in National Collegiate Athletic Association Athletes: A 6-Season Epidemiological Study

Background:

Lumbar spine injuries in National Collegiate Athletic Association (NCAA) athletes have not been well studied.

Purpose:

To describe the epidemiology of lumbar spine injuries in NCAA athletes during the 2009/2010 through 2014/2015 academic years utilizing the NCAA Injury Surveillance Program (ISP).

Study Design:

Descriptive epidemiology study.

Methods:

A voluntary convenience sample of NCAA varsity teams from 25 sports was examined. Mechanism of injury, injury recurrence, and time lost from sport were recorded. Injury rates were calculated as the number of injuries divided by the total number of athlete-exposures (AEs). AEs were defined as any student participation in 1 NCAA-sanctioned practice or competition. Injury rate ratios and injury proportion ratios were calculated to compare the rates within and between sports by event type, season, patient sex, mechanism, injury recurrence, and time lost from sport. Comparisons between sexes were made utilizing data that had both male and female samples.

Results:

An estimated 37,435 lumbar spine injuries were identified. The overall rate of injuries was 6.01 per 1000 AEs. The rate of injuries was 4.94 per 1000 AEs in men compared with 3.94 per 1000 AEs in women for sex-comparable sports. Men were 1.25 times more likely than women to suffer a lumbar spine injury. Men’s football (24.62 injuries/1000 AEs) and women’s gymnastics (11.46 injuries/1000 AEs) had the highest rates of lumbar spine injuries. Athletes were 1.83 and 3.71 times more likely to sustain a lumbar spine injury during the preseason than the regular season or postseason, respectively. Noncontact was the most common mechanism of injury (38%). Injury recurrence was most common in men’s outdoor track (58%). Most injuries resulted in less than 24 hours of time loss from event participation (61%).

Conclusion:

The rate of lumbar spine injuries was high in NCAA athletes, and injuries commonly recurred (20%). In general, men were more likely to sustain a lumbar spine injury compared with women. Higher injury rates occurred during competition and via a noncontact mechanism of injury. In addition to prevention programs, reconditioning programs should be considered to prevent these injuries.

Higher Rates of Lower Extremity Injury on Synthetic Turf Compared With Natural Turf Among National Football League Athletes: Epidemiologic Confirmation of a Biomechanical Hypothesis

BACKGROUND

Biomechanical studies have shown that synthetic turf surfaces do not release cleats as readily as natural turf, and it has been hypothesized that concomitant increased loading on the foot contributes to the incidence of lower body injuries. This study evaluates this hypothesis from an epidemiologic perspective, examining whether the lower extremity injury rate in National Football League (NFL) games is greater on contemporary synthetic turfs as compared with natural surfaces.

HYPOTHESIS

Incidence of lower body injury is higher on synthetic turf than on natural turf among elite NFL athletes playing on modern-generation surfaces.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Lower extremity injuries reported during 2012-2016 regular season games were included, with all 32 NFL teams reporting injuries under mandated, consistent data collection guidelines. Poisson models were used to construct crude and adjusted incidence rate ratios (IRRs) to estimate the influence of surface type on lower body injury groupings (all lower extremity, knee, ankle/foot) for any injury reported as causing a player to miss football participation as well as injuries resulting in ≥8 days missed. A secondary analysis was performed on noncontact/surface contact injuries.

RESULTS

Play on synthetic turf resulted in a 16% increase in lower extremity injuries per play than that on natural turf (IRR, 1.16; 95% CI, 1.10-1.23). This association between synthetic turf and injury remained when injuries were restricted to those that resulted in ≥8 days missed, as well as when categorizations were narrowed to focus on distal injuries anatomically closer to the playing surface (knee, ankle/foot). The higher rate of injury on synthetic turf was notably stronger when injuries were restricted to noncontact/surface contact injuries (IRRs, 1.20-2.03; all statistically significant).

CONCLUSION

These results support the biomechanical mechanism hypothesized and add confidence to the conclusion that synthetic turf surfaces have a causal impact on lower extremity injury.

Association between double-leg squat and single-leg squat performance and injury incidence among incoming NCAA Division I athletes: A prospective cohort study

OBJECTIVES

Determine the association between performance on the double-leg squat (DLS) and single-leg squat (SLS) and prospective injury incidence in athletes.

DESIGN

Prospective cohort study.

SETTING

National Collegiate Athletic Association (NCAA) Division I university.

PARTICIPANTS

111 incoming NCAA Division I athletes from 10 varsity sports teams.

MAIN OUTCOME MEASURES

Performance on the DLS and SLS were assessed as "poor" or "non-poor." Lower extremity (LE) injury data for the following year were extracted from electronic medical records. Multivariate Poisson regression was used to compare the incidence of LE injuries in athletes with poor versus non-poor performance on the DLS and SLS.

RESULTS

The final models for the DLS and SLS were adjusted for sex and LE injury history and yielded an incidence rate ratio (IRR) of 1.33 (95% CI: 0.80 2.22) for the DLS and 1.62 (95% CI: 0.98, 2.66) for the SLS when comparing poor to non-poor movers.

CONCLUSIONS

Athletes with poor LE movement quality assessed on the DLS or SLS had greater incidence of LE injury than those with non-poor movement quality. This is the first study to demonstrate an association between performance on the double-leg squat and single-leg squat and injury risk in NCAA athletes.

Epidemiology of Hip Flexor and Hip Adductor Strains in National Collegiate Athletic Association Athletes, 2009/2010-2014/2015

BACKGROUND

Little research has examined the rates and patterns of hip flexor or hip adductor strains in student-athletes in the National Collegiate Athletic Association (NCAA).

PURPOSE

To describe the epidemiology of hip flexor and adductor strains in NCAA athletes during the 2009/2010-2014/2015 academic years.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Rates and patterns of hip flexor and adductor strains in collegiate sports were examined in a convenience sample of NCAA varsity teams from 25 sports. Rates and distributions of strains by mechanism, recurrence, and participation restriction time were examined. Injury rate ratios (IRRs) and proportion ratios were calculated to compare rates within and between sports by event type, sex, mechanism, recurrence, and participation restriction time.

RESULTS

A total of 770 hip flexor and 621 hip adductor strains were reported, resulting in overall injury rates of 1.60 and 1.29 per 10,000 athlete-exposures (AEs), respectively. In men, the rate of hip flexor strains was 1.81 per 10,000 AEs, and that for hip adductor strains was 1.71 per 10,000 AEs. In women, the rate of hip flexor strains was 1.59 per 10,000 AEs, and the rate of hip adductor strains was 1.15 per 10,000 AEs. The highest rates of strains were found in men's soccer and men's ice hockey (range, 2.47-3.77 per 10,000 AEs). Most hip flexor and hip adductor strains occurred in practice, but both had higher rates in competition. In sex-comparable sports, hip flexor strain rates did not differ between the sexes (IRR = 1.14; 95% CI, 0.96-1.36), but the rate of hip adductor strains was higher in men than women (IRR = 1.49; 95% CI, 1.22-1.81). Noncontact was the most common mechanism for both types of strains (hip flexor strains, 59.4%; hip adductor strains, 62.5%); 10.1% of hip flexor strains and 11.1% of hip adductor strains were recurrent. The highest rates of recurrence of both types of strain were found in men's and women's ice hockey (range, 16.0%-30.6%). Most hip flexor and hip adductor strains resulted in <1 week of participation restriction (hip flexor strains, 83.8%; hip adductor strains, 82.9%).

CONCLUSION

The NCAA sports with the highest rates of hip flexor and hip adductor strains were men's soccer and men's ice hockey. In sex-comparable sports, men had a higher rate of hip adductor, but not hip flexor, strains. Recurrence rates were remarkably high in ice hockey. Male sports teams, especially soccer and ice hockey, should place an emphasis on prevention programs for hip adductor strains. Secondary prevention programs involving thorough rehabilitation and strict return-to-play criteria should be developed and implemented to curb the high recurrence rate of these injuries, particularly in ice hockey.