VOLUME FIFTEEN NUMBER FIVE

 
2020Masthead_V15N5

October 2020

SYSTEMATIC REVIEW/META-ANALYSIS
Authors: Power C, McCaulley B, Brosky ZS, Stephenson T, Hassen-Miller A
Adolescent athletes are experiencing an increased number of concussions. There is currently a debate within the medical community regarding the most effective and safe treatment approach for this population, post-concussion. Interventions currently range from cognitive and physical rest to various types of physical activity, including aerobic exercise. While there are systematic reviews that focus on rest as the main intervention, there are no other systematic reviews that focus on the effects of aerobic exercise on concussion recovery in adolescent athletes. Therefore, the aim of this systematic review and meta-analysis was to investigate the effectiveness of aerobic exercise on concussion recovery for adolescent athletes compared to an alternate intervention. A computer-based search was performed. Databases including PubMed, CINAHL, SPORTdiscus, ProQuest, and Scopus were searched up to December 2019 for randomized controlled trials published since 1965. A hand search of relevant articles and exploration of grey literature was also completed. Data were extracted for the following information: interventions prescribed, outcome measures, and overall results of the study. A meta-analysis was performed for aerobic interventions using standardized mean difference as the summary measure of effect. Five studies, which all held a moderate to low risk of bias according to the PEDro scale, met the inclusion criteria for this systematic review and meta-analysis. Overall results favored aerobic exercise for both acute and prolonged recovery symptoms as demonstrated by a decrease in symptom severity and improved recovery time. The meta-analysis revealed a moderate effect size in favor of the intervention group (SMD: 0.51, CI: 0.02, 0.81, p=0.00) when looking at the three outcome measures combined: Post-Concussion Symptom Scale, Post-Concussion Symptom Inventory, and recovery time. The results of this systematic review and meta-analysis indicate that there is currently moderately significant evidence in support of implementing an aerobic exercise program for adolescent athletes with both acute and prolonged recovery concussion symptoms. Additional higher quality studies are needed to continue to study the effectiveness of aerobic exercise in post-concussion treatment of adolescents.

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Authors: Freijomil N, Peters S, Millay A, Sinda T, Sunset J, Reiman MP
Reviews on superior labral anterior to posterior (SLAP) injuries have been reported in the literature. However, current reviews have not focused on the success of athletes return to their previous level of sport or athletic performance. The purpose of thie manuscript was to systematically review return to sport (RTS) and return to sport at previous level (RTSP) proportions after SLAP injury while reporting any additional performance metrics and outcome measures. A computer assisted literature search of MEDLINE, CINAHL, Embase and SportDiscus databases utilizing keywords related to RTS post-surgery for SLAP tear was implemented. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were utilized for study methodology. Quality assessment utilized the MINORS scale. Twenty-two studies (617 athletes) qualified for analysis. Based on limited evidence from level 3b to 4 studies, athletes RTS post intervention for SLAP injury occurred at a rate of 93% (95% CI:87 to 98%) and overall RTSP rate was 72% (95% CI:60 to 83%). The mean time to RTS post intervention was reported in 59% of studies at 6.9±2.9 months. Patient reported outcome measures (PROM’s) were reported in 86% of studies. There was limited reporting of performance statistics, rehabilitation guidelines, return to sport criteria, and information regarding SLAP diagnosis in the available studies. None of the included studies reported post-surgical athletic performance or career longevity. Limited evidence suggests that less than three in four athletes return to their previous level of sport participation after SLAP injury intervention. Treatment success for an athlete with SLAP injury remains relatively unknown as only 59% of included studies clearly delineate RTS from RTSP and neither athletic performance nor career longevity were reported in any included studies. Future studies of higher quality are required for this determination.

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Authors: Henn ED, Smith T, Ambegaonkar J, Wyon M
Low back pain is believed to be a common complaint among dancers; however, a comparison across recent research is needed to support or disprove this assertion across genres. The purpose of this review was to determine the prevalence of low back pain and low back injury in ballet, modern, and hip-hop dancers through a systematic literature review. A secondary goal was to identify trends amongst dance genres, level of mastery, gender, and age, if possible. PRISMA search strategy of terms relating to dance and low back pain was conducted within the Pubmed, MEDLINE, SPORTDiscus, Web of Science, and the archives of the Journal of Dance Medicine and Science databases between November 2017 and March 2018. Inclusion criteria were published articles that addressed low back pain or injury in ballet, modern, or hip-hop dance population. Exclusion criteria included studies relating to specific pathologies or studies that did not report specific dance genre. All included articles were assessed for quality using a modified grading evaluation and a Modified Newcastle-Ottawa Risk of Bias Assessment. Twenty-five ballet articles, five modern, and three hip-hop articles met the inclusion criteria, for a total of 33 articles. Twenty-five of the 33 studies relied on a questionnaire to gather data. Risk of bias results ranged from 3-7/10 and quality of studies ranged from Good I to Limited III. Prevalence of low back pain seems relatively high in ballet dance (range: 20.3%-79% of total dancers are affected). Little research exists on the prevalence of back pain in modern or hip-hop dancers, but hip-hop dancers also seem likely to have low back pain (range: 46.6%-85.7% of total dancers are affected). Low back injuries are also present in ballet (range: 2.1%-88% of total injuries), modern (range: 8.6%-21.6% of total injuries), and hip-hop (range: 26.3%-69.6%). Ballet dancers seem to be at risk for low back pain or injury independent of gender, age or level of mastery; however, there is not enough evidence to draw any conclusions about modern dancers or hip-hop dancers and their risk for low back pain/injury currently. Future higher-level studies are needed with reduced risk of bias.

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ORIGINAL RESEARCH
Authors:  Heick JD, Edgerton G, Raab S
Sport-related concussion is a public concern with between 1.6 and 3.8 million sport- and recreation-related injuries occurring annually. An estimated 65% to 90% of concussed athletes show oculomotor disruption such as difficulty with saccades, accommodation, smooth pursuit, and fixation. A rapid number-naming saccade test, the King-Devick (K-D) test, has shown promising results as part of a multifaceted concussion assessment tool. The purpose of the current study was to evaluate the two versions of the K-D in collegiate aged (18-24) athletes to determine the agreement between versions. A secondary purpose was to investigate the association of K-D scores with sport, sex, use of glasses or contacts, and age of the athlete. Division 1 NCAA collegiate athletes across ten sports were recruited to participate in baseline concussion assessments at the beginning of their respective athletic season. Correlations and multivariable logistic regression analyses were used to investigate the association of K-D scores with sex and age. One-hundred and nine athletes (69 males, 40 females; mean age = 20.40±1.38 years) were baseline tested. There was excellent agreement (ICC=0.93, 95% CI: 0.90, 0.95) between the paper and computer version. Preseason K-D scores were statistically different (r2=0.873, p<0.05) with athletes scoring a mean of 37.58 seconds on the paper version (95% CI, 36.21, 38.96) and athletes scoring a mean of 41.48 seconds for the computerized tablet version (95% CI, 40.17, 42.91). There were no significant differences in sex, sport, or use of glasses noted for both versions. Age differences were identified; eighteen-year-old athletes took statistically longer than their peers for both K-D versions. Pairwise comparisons showed statistically significant differences between 18-year olds up to the age of 21-year-olds (p<0.05) for the computer version and statistically significant differences between 18-year olds up to 22-year-olds (p<0.05) for the paper version.  This study supports the use of either version of the K-D test as a potential part of a multifaceted concussion assessment. The age of the athlete influences scores and therefore a K-D baseline should be repeated annually for collegiate athletes. Clinicians should not substitute K-D versions (computer vs. paper) in comparing baseline to a post-concussion K-D score as the scores are quite different. 

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Authors: Pontillo M, Sennett B
Analysis of upper extremity weight bearing ability is important for athletes, as some function largely in a closed chain capacity (e.g., wrestling, football, gymnastics), but also, all require closed chain upper extremity function during strength and conditioning. Additionally, in a rehabilitation setting, closed chain upper extremity functional testing is often used as a return to play criterion. Lower extremity sway measures (biomechanical and clinical) have been published widely and have established reliability and validity; however, the reliability of upper extremity sway biomechanical measures has not been investigated to date. The purpose of this study was to determine the repeatability of a variety of force plate measurements during an upper extremity task in an athletic population. It was hypothesized that variables measuring upper extremity sway in a closed kinetic chain position would have excellent reliability. All data were collected using a force plate system with commercially available software. Four hundred and ninety healthy Division I athletes were tested for both their dominant and non-dominant upper extremity at one of two testing sessions. Subjects were instructed to stay as still as possible while maintaining a full plank position with one upper extremity on the force plate and the contralateral upper extremity behind their back. Two, 20-second trials were performed for each extremity. Variables measured included average sway velocity (ASV), sway velocity in medial-lateral (SVML) and anterior-posterior (SVAP) directions, sway velocity at 1st and 2nd time intervals for AP (VAP1 and 2) and ML (VML1 and 2) directions, and sway frequency in the AP direction for 1st and 2nd time intervals (FreAP1 and 2). Intraclass correlation coefficients (ICC (2,1)) and their 95% confidence intervals were calculated for all force plate variables for 980 limbs. No difference was seen between left and right extremities for any measure (p > 0.05). ICC’s ranged from 0.61-0.90 for all variables, indicating moderate to excellent reliability for all variables.  Upper extremity sway biomechanical variables using a force plate system have moderate to excellent reliability. These results are important prior to validation and clinical utilization of these measures for purposes including baseline testing, return to play testing, and establishment of injury prevention parameters.

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Authors: Ellenbecker TS, Dickenson S
Rehabilitation following shoulder surgery involves the use of resistive exercise but dosing of these exercises historically employs multiple sets of pre-determined repetitions and few reports document the perceived effort encountered by patients during these exercises for both elastic resistance and free-weights. The OMNI-Resistance Exercise Scale (OMNI-RES) has been tested and applied as a measure of perceived exertion (RPE) for resistive exercise but has not gained widespread acceptance as an optimal method for physical therapists to document RPE during rehabilitation of shoulder surgery. The purpose of this study was to generate descriptive values of RPE encountered during common shoulder exercises of varying resistance in patients following shoulder surgery as well as provide a comparative analysis between perceived exertion ratings of similar exercise movement patterns using elastic and traditional isotonic resistance. Sixty-six subjects (mean age 53.3+12.8 years) were included in this study following shoulder surgery (RC repair n=22, labral repair n=10, SA n=34). Perceived exertion using the OMNI-RES was recorded during performance of seven rotator cuff and scapular rehabilitation exercises at 6- and 12-weeks following surgery.  Mean RPE using OMNI-RES in combined surgical groups ranged between 3.6 and 5.7 (mean = 4.50+2.1) across all seven exercises (scale 0 = very easy to 10 = extremely hard). From the external rotation (ER) exercise pair, paired t-tests revealed standing ER w/ Thera-band® (ERB) had a significantly higher OMNI-RES score versus sidelying ER w/ cuff weight (SLERW) (mean: 5.13 vs 4.41, p= 0.001) while the extension exercise pair consisting of standing shoulder extension w/ band (EXTB) and prone extension w/ cuff weight (PEXTW) showed no significant difference in OMNI-RES score (mean: 3.54, 3.67, p= 0.626). Commonly prescribed resistance exercise in the rehabilitation following shoulder surgery show light-moderate ratings of perceived exertion at both 6 & 12 week post-operative timepoints across three surgical procedures.

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Authors: Tao H, Husher A, Schneider Z, Strand S, Ness B
Impaired balance and strength commonly affect athletes with conditions like chronic ankle instability (CAI). Yet, clinical research surrounding the relationship between balance, strength, and CAI is still growing. Deeper investigation of these relationships is warranted to better inform clinical practice patterns when managing athletes with balance deficits. The purpose of this study was to investigate the relationship between single leg balance, ankle strength, and hip strength in healthy, active adults. Forty healthy participants (age 23.7 ± 4.9 years) were assessed for static balance, using a modified version of the Balance Error Scoring System (mBESS), as well as isometric strength of ankle and hip musculature via handheld dynamometry. Pearson’s correlations were used to analyze relationships between balance and strength measures. Paired t-tests were utilized to compare dominant and non-dominant limb performance. Negligible to low, negative correlations were found between balance scores and hip extension strength (r = -0.24 to -0.38, p<0.05). High, positive correlations were found between ankle and hip strength measures (r = 0.75 to 0.84, p<0.05). When comparing dominant to non-dominant limbs, only minimal differences were noted in ankle eversion strength (mean difference = 6.0%, p<0.01) and hip extension strength (mean difference = 5.5%, p<0.01). Minimal relationships were identified between static balance and isometric ankle and hip strength. Comparison of dominant and non-dominant limbs suggests that clinicians should expect relative symmetry in balance and strength in healthy adults. Thus, asymmetries found during clinical examination should raise suspicion of specific impairments that may lead to dysfunction.

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Authors: Boey D, Lee MJC
Using 3-dimensional motion analysis to derive knee moments that may contribute to non-contact anterior cruciate ligament (ACL) injuries during single-leg jump-landing is expensive and time consuming. Severe ACL injuries that are inappropriately rehabilitated can potentially end athletes’ careers. Consequently, a quick-and-simple to administer screening tool that can be used to infer knee moments during single-leg jump-landing could be useful for regular screening of netballers’ predispositions to increased knee loading during single-leg jump-landing. The purpose of this study was to investigate whether knee moments during weight-acceptance phase of a forward single-leg jump for maximal distance were correlated with reach scores in the Y-Balance Test (YBT). Twenty-one female national-level netballers performed two and three successful trials on the YBT and forward single-leg jump-landing, respectively, with the non-dominant leg. A three-dimensional motion analysis system captured trunk and lower limb kinematics and ground reaction forces of the non-dominant leg during landing. Averages of peak knee flexion-extension, valgus-varus and internal-external rotation moments across jumps were calculated and correlations with peak directional reach scores were examined. A strong positive correlation existed between posteromedial reach with externally applied flexor moments (r = 0.56, p = ≤ 0.01). A moderate negative correlation existed between anterior reach distances with internal rotation moments (Tb = -0.32, p = 0.05). No correlation was found between valgus moments and YBT reaches.  The YBT shows potential to indicate externally applied flexion- and internal rotation moments during forward jump-landing on the non-dominant leg.

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Authors:  Cornell DJ, Ebersole KT
In contrast to static stretching (SS), previous research has demonstrated increases in flexibility after an acute bout of self-myofascial release (SMR) without any subsequent decreases in force output. Previous research has utilized measures of surface electromyography (sEMG) and mechanomyography (MMG) to examine the influence of SS on the electrical and mechanical processes of muscle activation, respectively. However, there is a lack of research examining the potential changes in electro-mechanical muscle activation post-SMR. The purpose of this study was to examine the influence of SMR, via an acute bout of foam rolling (FR) to the vastus lateralis (VL), on the expression of knee extension force output and the inter-muscular electro-mechanical activation of the quadriceps musculature. Twenty (10 males, 10 females) recreationally-active participants with prior FR experience completed both SMR and control (CON) testing protocols during separate testing sessions that were conducted in a randomized order 48 hours apart. During the SMR protocol, participants performed 3 sets of 60 seconds of FR over the VL portion of their quadriceps musculature, with 60 seconds of rest between sets. During the CON protocol, participants quietly sat upright for 10 minutes. Peak knee extension force output (Forcepeak) data, as well as sEMG and MMG data from the VL and the rectus femoris (RF) were collected during maximal voluntary isometric contractions (MVICs) before and after both testing protocols. Root mean square sEMG and MMG amplitudes were calculated to represent electro-mechanical muscle activation of the VL (VL–sEMGRMS, VL–MMGRMS) and RF (RF–sEMGRMS, RF–MMGRMS) musculature. Repeated measures analyses of variance (RM ANOVAs) identified a significant (p < 0.05) increase in Forcepeak within the SMR protocol among males, but no change among females. No statistically significant changes in any electro-mechanical muscle activation measures were identified pre-to-post-SMR in either sex. In contrast to the SS literature body, these results suggest that SMR does not influence the electro-mechanical aspects of muscle activation during MVICs. These results provide support for the absence of decreases in force output post-SMR, but further examination regarding the potential muscle mass influence of SMR on electro-mechanical muscle function remains warranted.

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<divAuthors: Arhos EK, Capin JJ, Ito N, Synder-Mackler L </div
Anterior cruciate ligament injuries are among the most common knee injuries. Mechanism of injury is classified as contact or non-contact. The majority of anterior cruciate ligament ruptures occur through a non-contact mechanism of injury. Non-contact anterior cruciate ligament ruptures are associated with biomechanical and neuromuscular risk factors that can predispose athletes to injuries and may impact future function. Non-contact mechanism of injury may be preceded by poor dynamic knee stability and therefore those with a non-contact mechanism of injury may be prone to poor dynamic knee stability post-operatively. Understanding how mechanism of injury affects post-operative functional recovery may have clinical implications on rehabilitation. The purpose of this study was to determine if mechanism of injury influenced strength, functional performance, patient-reported outcome measures, and psychological outlook in athletes at four time points in the first two years following anterior cruciate ligament reconstruction. Seventy-nine athletes underwent functional testing at enrollment after impairment resolution. Quadriceps strength, hop testing, and patient-reported outcome measures were evaluated post-operatively at enrollment, following return-to-sport training and one year and two years after anterior cruciate ligament reconstruction. Participants were dichotomized by mechanism of injury (29 contact, 50 non-contact). Independent t-tests were used to compare differences between groups. There were no meaningful differences between contact and non-contact mechanism of injury in any variables at enrollment, post-training, one year, or two years after anterior cruciate ligament reconstruction. Function did not differ according to mechanism of injury during late stage rehabilitation or one or two years after anterior cruciate ligament reconstruction.

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Authors: Krause DA, Hollman JH
Slider exercises, which may use a gliding disc or “slider”, are dynamic exercises commonly used for strengthening. They are proposed to increase challenge as the friction between the body and ground is decreased which increases the demands on muscles of the weight bearing limb. The purposes of this study were (1) to compare the electromyographic (EMG) activity level of hip muscles of the weight bearing limb while performing a single limb slide squat to that of a standard isometric squat and (2) to investigate the influence of trunk position on hip EMG activity. It was hypothesized that the single limb slide squat would elicit greater hip EMG activity than an isometric squat and trunk position would influence EMG activity. Twenty healthy male participants (age = 23.7 ± 1.3) volunteered. EMG hip muscle activation of the stance leg was measured during a single limb slide squat and as a comparison, the same leg during a standard double limb isometric squat. Both exercises where performed with a knee flexion angle of 60˚ and the trunk positioned 40˚ (flexed trunk) and 60˚ (upright trunk) relative to the floor. Surface electrodes were used to collect EMG data. EMG activity of the gluteus maximus, gluteus medius, biceps femoris and rectus femoris was significantly greater with both single limb slide exercises as compared to both squat exercises. EMG activity was greater with the flexed trunk as compared to the upright trunk for the biceps femoris. Slider exercises produced a moderate or high level of activation for all muscles whereas all squat exercises produced a low-level activation. 

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Hip and groin problems in the previous season are associated with impaired function in the beginning of the new season among professional female ice hockey players - a cross sectional study.
Authors: Worner T, Thorborg K, Eek F
Hip and groin problems are common in ice hockey, however, studies on professional female players are sparse. The available literature describes hip and groin problems by reporting incidence of time-loss injuries and may thereby underestimate the scope of these problems, which are often due to overuse and may not lead to absence from ice hockey participation. The purpose of this study was to describe the seasonal prevalence and severity of hip and groin problems in professional female ice hockey players. A further aim was to examine the relation between previous problems and self-reported function in the beginning of the new season. Female ice hockey players from the highest league in Sweden [n=69 (19 goalkeepers, 18 defenders, 30 forwards)], responded to an online survey, retrospectively assessing the prevalence of hip and groin problems (time loss and non-time loss) and their duration during the previous season. Furthermore, players reported current self-reported function using the Copenhagen Hip and Groin Outcome Score (HAGOS). Two thirds of the players experienced hip and groin problems during the previous season [62.3% (N=43)]. A quarter of the players experienced a hip and groin problem leading to time loss [26.1% (N=18)]. The majority of problems were of short (1-2 weeks) or medium (3-5 weeks) duration [29% (N=20) of players, respectively], while longstanding problems (≥ 6 weeks) were rare [4,4% (N=3)]. Players that retrospectively reported hip and groin problems during the previous season reported statistically significant impairments on all HAGOS subscales in the beginning of the new season (p ≤0.011). Hip and groin problems are prevalent in professional female ice hockey players, experienced by 62% during the previous season with resulting time-loss in 26.1%. Reported problems were rarely longstanding in nature, but players who reported problems in the previous season had significantly impaired hip and groin function in the beginning of the new season. Even though results of this study are based on retrospective player reports this may be a first step toward a greater understanding of the true burden of hip and groin players in professional female ice hockey players.

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Authors: Beyer EB, Hale RF, Hellem AR, Mumbleau AM, Schilaty ND, Hewett TE
Non-contact injuries are common in sports as abnormal lower extremity joint mechanics can place athletes at risk for injury. It is important to have reliable, feasible, cost-effective assessment tools to determine lower limb control and injury risk.  The purpose of the study was to assess the intra- and inter-rater reliability of a three-tiered anterior cruciate ligament (ACL) injury risk rating assessment of the drop vertical jump using frontal plane, two-dimensional (2-D) motion capture. Twenty male elite basketball athletes performed the drop vertical jump during a 2-D video assessment at Mayo Clinic Sports Medicine Center. DVJ was scored using the following criteria: 1 no visible knee valgus, 2 slight wobble, inward motion of the knees, and 3 knee collision or large frontal plane knee excursion. Scoring of the video of the drop vertical jump (at four defined points) was completed by four independent investigators. The four raters then re-examined the same videos one month later, blinded to their original scores.  Intra-rater reliability Fleiss Kappa measure of agreement was substantial amongst all four raters at all scoring time points: initial contact (0.672), first landing (0.728), second landing (0.670), and peak valgus (0.662) (p<0.001). The intra-rater ICC values were good at initial contact (0.809), second landing (0.874), and max valgus (0.885), however were excellent at first landing (0.914) (p<0.001). Inter-rater reliability Fleiss Kappa measurement scores were slight at initial contact (0.173), fair at max valgus (0.343), and moderate at first landing (0.532) and second landing (0.514; p <0.001). Inter-rater ICC values were moderate at initial contact (0.588), excellent at first landing (0.919), and good at second landing (0.883) and max valgus (0.882; p<0.001). When comparing scores of the drop vertical jump between four independent raters across two sessions, the study demonstrated substantial Kappa and good to excellent ICC intra-rater reliability. Inter-rater reliability demonstrated slight to moderate Kappa measurements of agreement and moderate to excellent ICC’s. Thus, for excellent reliability using this assessment, patients should be scored by one individual. For moderate reliability between multiple raters, the first landing of the DVJ should be scored. Findings indicate that the proposed drop vertical jump assessment may be used for reliable identification of abnormal landing mechanics. 

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Authors: Olivencia O, Godinez GM, Dages J, Duda C, Kaplan K, Kolber MJ
Muscle length is a common component of the physical therapy examination, which may include the prone knee flexion (Ely) and active knee extension (AKE) tests. Clinicians using these tests should understand the clinimetric properties. The purpose of thei study was to investigate the reliability and minimal detectable change (MDC) of the Ely and AKE tests. Seventy-one asymptomatic adults (mean age 24.6 +/- 2.8 years) were recruited based on a convenience sample. Two examiners each performed the Ely and AKE test one time each in an intrasession design for the interrater reliability component, with one examiner repeating the tests one time 48 hours later to determine the intra-rater reliability. Results were recorded based on one trial per test and utilized a pelvic strap for the Ely test and an adjustable bolster for the AKE test. A separate researcher recorded measurements and results were blinded from the examiners. The Ely test had excellent intra-rater and inter-rater reliability with an intraclass correlation coefficient (ICC) (3,1) of 0.900 and ICC (2,1) of 0.914 respectively. The intra-rater and inter-rater reliability of the AKE test was good with ICC (3,1) of 0.882 and ICC (2,1) 0.886 respectively. The MDC95 indicated that a change greater than or equal to 8° and 12° is required to exceed the threshold of error for the Ely and AKE test respectively.  The Ely and AKE tests have good to excellent inter-rater and intra-rater reliability for measuring rectus femoris and hamstring muscle length when stabilization of the pelvis and hip is accounted for. The MDC should be considered as a threshold for true change in the asymptomatic adult population.

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Authors: Brekke AF, Sorensen AN, Madsen CS, Johannesdottir IO, Jakobsen TL
The limb occlusion pressure (LOP) is determined to calculate the relative LOP. The different levels of relative LOP (percentage of LOP) influence the treatment effect and perceived discomfort during low-load blood flow restriction (BFR) strength training. Thus, determining the LOP is of the utmost importance when using BFR in clinical practice. The objective of this study was to investigate the concurrent validity and intra-rater (test-retest), intra-day reliability of an inexpensive, portable, easy-to-use handheld (HH) oximeter compared to a high-resolution Doppler ultrasound scanner in detecting LOP in the lower extremity.  Two raters who were blinded from each other simultaneously assessed 50 healthy participants (mean age of 25.8 years). A 20 cm-wide thigh cuff with an attached sphygmomanometer was inflated until the raters independently registered the LOP with the HH oximeter and the Doppler ultrasound scanner. The test session was repeated once after a five-minute time interval. The HH oximeter recorded a non-significantly higher LOP than the Doppler ultrasound scanner, with a mean difference of 6.3 mmHg in the test session (95% limits of agreement (LoA): -16.2 to 28.8, p = 0.13) and 5.4 mmHg in the retest session (95% LoA: -13.3 to 24.0, p = 0.10). The intra-rater reliability for both devices was moderate (ICC = 0.72-0.79). The measured LOP was significantly lower (p < 0.005) in the retest session than in the test session for both the HH oximeter (mean difference: -5.7 mmHg) and the Doppler ultrasound scanner (mean difference: -4.8 mmHg). The authors concluded that the HH oximeter is a valid and reliable measuring device for determining the LOP in the lower extremity in healthy adults. The authors recommend performing at least two LOP measurements with a one-minute rest interval.

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Authors: Cross KM, McMurray M, Hertel J, Mangrum E, Templeton R, Brockmeier S, Gwathmey F
Recent research has focused on the epidemiology of shoulder and elbow injuries among high school and professional baseball players. Shoulder and elbow injury data has not been comprehensively reported among college baseball student-athletes. The purpose of this study is to describe shoulder and elbow injury rates and their characteristics among collegiate baseball student-athletes in order to improve injury prevention. Shoulder and elbow injury data were obtained from the NCAA Injury Surveillance System for baseball from 2004-2014. Incidence rate ratios and descriptive analyses described injury characteristics for the shoulder and elbow, separately. The injury rate for the shoulder was 4.02/10,000 athlete-exposures and for the elbow was 2.44/10,000 athlete-exposures. During the ten-year period, the injury rate of the shoulder has approximately decreased by 75% and of the elbow by approximately 50%. Injury rates were higher during competitions compared to practice for the shoulder (rate ratio, 1.81;95% CI, 1.51, 2.18) and elbow (rate ratio, 2.19;95% CI, 1.73, 2.78). Freshmen and juniors were most likely to sustain shoulder (F=40.6%, J =29%) and elbow (F=33%, J=33.7%) injuries. Regarding shoulder injuries, surgery was required for 7.1%, and the outcome was season ending for 14.5%. More elbow injuries (17.5%) ended in surgery, and a greater proportion (28.9%) had season-ending injuries. In collegiate baseball, shoulder and elbow injury rates have decreased but still result in high morbidity. More granular analyses, especially during Division 1 competitions, are necessary for more specific interventions. While shoulder injuries are more common, elbow injuries result in a longer time to return to play and a higher proportion of surgical interventions.

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CASE SERIES / REPORTS
Authors: Vineyard AP, Gallucci AR, Imbus SR, Garrison JC, Conway JE
Literature regarding musculocutaneous nerve injuries among the athletic population is scarce, with only several reported clinical cases among baseball and softball pitchers. The purpose of this case report is to present a unique case of a musculocutaneous nerve injury to aid in clinician awareness and propose innovative rehabilitation practices that may facilitate improved patient outcomes during recovery.

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Authors: Krueger K, Washmuth NB, Williams TD
Proximal hamstring tendinopathy is a chronic, overuse condition that commonly develops in athletes. Eccentric exercise has been widely accepted in the clinic as the treatment of choice for the management of tendinopathies. However, this form of treatment has seldom been compared to other forms of load-based management for hamstring tendinopathies. Heavy slow resistance training, which consists of both concentric and eccentric phases, increases the loading time experienced by the tendon compared to eccentric only exercises. Heavy slow resistance training has achieved positive clinical results in the management of Achilles and patellar tendinopathy. The purpose of this case report is to describe the outcomes of a powerlifter with proximal hamstring tendinopathy who responded favorably to a heavy slow resistance biased rehabilitation program after traditional, conservative management failed to alleviate symptoms.

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Authors: Taylor JB, Owen E, Ford KR
Second anterior cruciate ligament (ACL) injury rates continue to be high, with a majority of injuries occurring soon after return-to-play, potentially because athletes may not be ready for the external load demands of the sport. Load metrics, tracked through wearable technology, may provide complementary information to standard limb symmetry indices in the return-to-play decision making process. The purpose of this case report was to quantify and monitor load using innovative technology during physical therapy rehabilitation after ACL reconstruction (ACLr) and compare to normative sport participation data.

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Authors: Waldron JL, McKenney MA, Samuel MN, Girouard TJ, Turner CL, Radzak KN
Postural Restoration Institute® (PRI) theories and rehabilitation techniques focus on restoring balance to anatomical systems. Common postural asymmetries can present in athletes as dysfunctions and limitations. The purpose of this case report was to examine the use of PRI exercises and theories to address pelvic alignment, along with core stabilization, during treatment of shoulder dysfunction in a collegiate volleyball player.

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