Nicole J. Chimera

Association of Y Balance Test Reach Asymmetry and Injury in Division I Athletes.

PURPOSE The Y balance test (YBT) is a screen of dynamic balance requiring stance leg balance while the contralateral leg reaches in anterior (ANT), posteromedial (PM), and posterolateral (PL) directions. YBT has been proposed as a screen for injury risk; however, limited research has examined the association between YBT and injury. The purpose of this study was to examine the association between YBT (asymmetry and composite score (CS)) and noncontact injury in a sample of Division I (DI) college athletes from multiple sports. METHODS DI college athletes were screened with the YBT during the preparticipation examination to determine asymmetry (absolute difference between legs in ANT, PL, and PM) and CS (summed average of right/left ANT, PL, and PM normalized to leg length). Participants were followed throughout the sport season, and noncontact injuries requiring athletic training staff intervention were recorded for analysis. Demographic variables between injured and uninjured athletes were assessed with independent t-tests. Receiver operating characteristic (ROC) curves determined optimal cut points for predicting injury on the basis of CS and asymmetry. CS was analyzed as a continuous variable, as ROC curves were unable to maximize sensitivity and specificity. Logistic regression models adjusted for sport and previous injury determined the odds of injury on the basis of asymmetry and CS. RESULTS One hundred and eighty-four participants were included in analysis; 81 were injured. ROC curves determined asymmetry >4 cm (sensitivity, 59%; specificity, 72%) as the optimal cut point for predicting injury. Only ANT asymmetry was significantly associated with noncontact injury (odds ratio, 2.33; 95% confidence interval, 1.15-4.76). CONCLUSIONS ANT asymmetry >4 cm was associated with increased risk of noncontact injury. CS in this sample of DI athletes was not associated with increased risk of injury.

Function and strength following gastrocnemius recession for isolated gastrocnemius contracture.

Background: Isolated gastrocnemius contracture (IGC), which limits ankle dorsiflexion with full knee extension, can affect function and quality of life. Gastrocnemius recession is a treatment option for IGC when conservative treatment fails. The goal of this study was to assess range of motion, function, and plantarflexion strength pre- and 3-months post-gastrocnemius recession for subjects with IGC. Materials and Methods: Ankle range of motion, function, and plantarflexion strength in seven legs (four subjects), clinically diagnosed with IGC, before and after surgery were compared to matched control subjects to elucidate pre- and post-surgical intervention differences. All subjects with IGC were also diagnosed with plantar fasciitis with one leg having an additional diagnosis of metatarsalgia. Results: Subjects with IGC had significant post surgical improvements at 3 months after surgery in dorsiflexion range of motion (p = 0.016), function (p = 0.016) and isokinetic plantarflexion strength (p = 0.018). Conclusions: Surgical recession enhanced range of motion and self reported function while not inducing any detrimental effects to plantarflexion strength at a 3-month followup. Post-surgically IGC subjects were more similar to healthy controls. Level of Evidence: III, Case Control Series

Association of the Functional Movement Screen With Injuries in Division I Athletes

CONTEXT The Functional Movement Screen (FMS) evaluates performance in 7 fundamental movement patterns using a 4-point scale. Previous studies have reported increased injury risk with a composite score (CS) of 14/21 or less; these studies were limited to specific sports and injury definition. OBJECTIVE To examine the association between FMS CS and movement pattern scores and acute noncontact and overuse musculoskeletal injuries in division I college athletes. An exploratory objective was to assess the association between injury and FMS movement pattern asymmetry. DESIGN Prospective cohort. SETTING College athletic facilities. PARTICIPANTS 167 injury-free, college basketball, football, volleyball, cross country, track and field, swimming/ diving, soccer, golf, and tennis athletes (males = 89). INTERVENTION The FMS was administered during pre-participation examination. MAIN OUTCOME MEASURE Noncontact or overuse injuries that required intervention from the athletic trainer during the sport season. RESULTS FMS CS was not different between those injured (n = 74; 14.3 ± 2.5) and those not (14.1 ± 2.4; P = .57). No point on the ROC curve maximized sensitivity and specificity; therefore previously published cut-point was used for analysis with injury (≤ 14 [n = 92]). After adjustment, no statistically significant association between FMS CS and injury (odds ratio [OR] = 1.01, 95% CI 0.53-1.91) existed. Lunge was the only movement pattern that was associated with injury; those scoring 2 were less likely to have an injury vs those who scored 3 (OR = 0.21, 95% CI 0.08-0.59). There was also no association between FMS movement pattern asymmetry and injury. CONCLUSION FMS CS, movement patterns, and asymmetry were poor predictors of noncontact and overuse injury in this cohort of division I athletes.

The effect of isolated gastrocnemius contracture and gastrocnemius recession on lower extremity kinematics and kinetics during stance

BACKGROUND Isolated gastrocnemius contracture limits ankle dorsiflexion with full knee extension and is potentially problematic during mid-stance of gait when 10° of dorsiflexion and full knee extension are needed. It is during this time that patients with isolated gastrocnemius contracture may demonstrate altered kinematics and/or kinetics. When conservative management fails to resolve painful foot pathologies associated with non-spastic isolated gastrocnemius contracture, gastrocnemius recession surgery has been suggested to resolve contracture and improve function and strength. However, there are no published reports on lower extremity kinematics/kinetics in the non-spastic isolated gastrocnemius contracture population. Assessment of alterations in gait mechanics is necessary to examine the effects of this potential surgical intervention. METHODS Lower extremity kinematics and kinetics were assessed in 6 patients clinically diagnosed with isolated gastrocnemius contracture pre- and post-surgical recession compared with 33 healthy control participants. FINDINGS Pre-operatively, patients with isolated gastrocnemius contracture demonstrated significantly increased peak knee flexion angles and knee flexion moments during mid-stance. There were no differences in peak ankle dorsiflexion angle or peak plantar flexion moment. Gastrocnemius recession did not alter gait kinematics/kinetics following surgery. Joint kinematic strategies utilized to compensate for isolated gastrocnemius contracture varied minimally between participants with IGC; most employed a flexed knee strategy, while one participant utilized a reduced ankle dorsiflexion strategy. INTERPRETATION Select post-surgical gait mechanics were unaltered; however, gait mechanics were not similar between non-spastic isolated gastrocnemius contracture patients and healthy control participants. Surgical intervention for patients with isolated gastrocnemius contracture does not appear to create any negative gait adaptations; however, patients may benefit from gait retraining post-recession as maladaptive gait patterns persist post operatively.

Injury History, Sex, and Performance on the Functional Movement Screen and Y Balance Test

CONTEXT Research is limited regarding the effects of injury or surgery history and sex on the Functional Movement Screen (FMS) and Y Balance Test (YBT). OBJECTIVE To determine if injury or surgery history or sex affected results on the FMS and YBT. DESIGN Cross-sectional study. SETTING Athletic training facilities. PATIENTS OR OTHER PARTICIPANTS A total of 200 National Collegiate Athletic Association Division I female (n = 92; age = 20.0 ± 1.4 years, body mass index = 22.8 ± 3.1 kg/m(2)) and male (n = 108; age = 20.0 ± 1.5 years, body mass index = 27.0 ± 4.6 kg/m(2)) athletes were screened; 170 completed the FMS, and 190 completed the YBT. INTERVENTION(S) A self-reported questionnaire identified injury or surgery history and sex. The FMS assessed movement during the patterns of deep squat, hurdle step, in-line lunge, shoulder mobility, impingement-clearing test, straight-leg raise, trunk stability push-up, press-up clearing test, rotary stability, and posterior-rocking clearing test. The YBT assessed balance while participants reached in anterior, posteromedial, and posterolateral directions. MAIN OUTCOME MEASURE(S) The FMS composite score (CS; range, 0-21) and movement pattern score (range, 0-3), the YBT CS (% lower extremity length), and YBT anterior, posteromedial, and posterolateral asymmetry (difference between limbs in centimeters). Independent-samples t tests established differences in mean FMS CS, YBT CS, and YBT asymmetry. The Mann-Whitney U test identified differences in FMS movement patterns. RESULTS We found lower overall FMS CSs for the following injuries or surgeries: hip (injured = 12.7 ± 3.1, uninjured = 14.4 ± 2.3; P = .005), elbow (injured = 12.1 ± 2.8, uninjured = 14.3 ± 2.4; P = .02), and hand (injured = 12.3 ± 2.9, uninjured = 14.3 ± 2.3; P = .006) injuries and shoulder surgery (surgery = 12.0 ± 1.0, no surgery = 14.3 ± 2.4; P < .001). We observed worse FMS movement pattern performance for knee surgery (rotary stability: P = .03), hip injury (deep squat and hurdle: P < .042 for both), hip surgery (hurdle and lunge: P < .01 for both), shoulder injury (shoulder and hand injury: P < .02 for both), and shoulder surgery (shoulder: P < .02). We found better FMS movement pattern performance for trunk/back injury (deep squat: P = .02) and ankle injury (lunge: P = .01). Female athletes performed worse in FMS movement patterns for trunk (P < .001) and rotary (P = .01) stability but better in the lunge (P = .008), shoulder mobility (P < .001), and straight-leg raise (P < .001). Anterior asymmetry was greater for male athletes (P = .02). CONCLUSIONS Injury history and sex affected FMS and YBT performance. Researchers should consider adjusting for confounders.

Interrater and Intrarater Reliability of the Tuck Jump Assessment by Health Professionals of Varied Educational Backgrounds

Objective. The Tuck Jump Assessment (TJA), a clinical plyometric assessment, identifies 10 jumping and landing technique flaws. The study objective was to investigate TJA interrater and intrarater reliability with raters of different educational and clinical backgrounds. Methods. 40 participants were video recorded performing the TJA using published protocol and instructions. Five raters of varied educational and clinical backgrounds scored the TJA. Each score of the 10 technique flaws was summed for the total TJA score. Approximately one month later, 3 raters scored the videos again. Intraclass correlation coefficients determined interrater (5 and 3 raters for first and second session, resp.) and intrarater (3 raters) reliability. Results. Interrater reliability with 5 raters was poor (ICC = 0.47; 95% confidence intervals (CI) 0.33–0.62). Interrater reliability between 3 raters who completed 2 scoring sessions improved from 0.52 (95% CI 0.35–0.68) for session one to 0.69 (95% CI 0.55–0.81) for session two. Intrarater reliability was poor to moderate, ranging from 0.44 (95% CI 0.22–0.68) to 0.72 (95% CI 0.55–0.84). Conclusion. Published protocol and training of raters were insufficient to allow consistent TJA scoring. There may be a learned effect with the TJA since interrater reliability improved with repetition. TJA instructions and training should be modified and enhanced before clinical implementation.

Use of clinical movement screening tests to predict injury in sport

Clinical movement screening tests are gaining popularity as a means to determine injury risk and to implement training programs to prevent sport injury. While these screens are being used readily in the clinical field, it is only recently that some of these have started to gain attention from a research perspective. This limits applicability and poses questions to the validity, and in some cases the reliability, of the clinical movement tests as they relate to injury prediction, intervention, and prevention. This editorial will review the following clinical movement screening tests: Functional Movement Screen™, Star Excursion Balance Test, Y Balance Test, Drop Jump Screening Test, Landing Error Scoring System, and the Tuck Jump Analysis in regards to test administration, reliability, validity, factors that affect test performance, intervention programs, and usefulness for injury prediction. It is important to review the aforementioned factors for each of these clinical screening tests as this may help clinicians interpret the current body of literature. While each of these screening tests were developed by clinicians based on what appears to be clinical practice, this paper brings to light that this is a need for collaboration between clinicians and researchers to ensure validity of clinically meaningful tests so that they are used appropriately in future clinical practice. Further, this editorial may help to identify where the research is lacking and, thus, drive future research questions in regards to applicability and appropriateness of clinical movement screening tools.

Performance Comparison of Student-Athletes and General College Students on the Functional Movement Screen and the Y Balance Test

Abstract Engquist, KD, Smith, CA, Chimera, NJ, and Warren, M. Performance comparison of student-athletes and general college students on the Functional Movement Screen and the Y Balance Test. J Strength Cond Res 29(8): 2296–2303, 2015—Although various studies have assessed performance of athletes on the Functional Movement Screen (FMS) and the Y Balance Test (YBT), no study to date has directly evaluated a comparison of performance between athletes and members of the general population. Thus, to better understand the application of the FMS and the YBT to general college students, this study examined whether or not general college students performed similarly to student-athletes on the FMS (composite and movement pattern scores) and the YBT (composite and reach directions). This study evaluated 167 Division I student-athletes and 103 general college students from the same university on the FMS and the YBT. No difference was found in FMS composite scores between student-athletes and general college students. For FMS movement patterns, female student-athletes scored higher than general college students in the deep squat. No difference was found for men in any FMS movement pattern. Female student-athletes scored higher than female general college students in YBT composite scores; no difference was found for men in YBT composite scores. In analysis of YBT reach directions, female student-athletes scored higher than female general college students in all reach directions, whereas no difference was found in men. Existing research on the FMS composite score in athletic populations may apply to a general college population for the purposes of preparticipation screening, injury prediction, etc. Existing research on the YBT in male athletic populations is expected to apply equally to general college males for the purposes of preparticipation screening, injury prediction, etc.

Influence of electrode type on neuromuscular activation patterns during walking in healthy subjects

The role of muscle activation in both pathological and spastic populations is of interest for understanding central nervous system function. Muscle activation patterns may provide insight into pathological changes compared to healthy controls. To gain a better understanding of surgical interventions, gait muscle activation patterns are studied before and after surgery. Previous studies using surface electromyography have indicated that muscle activation onset, time to peak, and peak amplitude may be helpful in assessing the neuromuscular control strategy that underlies pathological populations. Geometric artifact may influence electromyographic variables as recorded by different electrode types and electrode placement. The purpose of this investigation was to compare surface and fine-wire activation patterns during gait to elucidate the influence electrode type has on electromyographic variables. Lower leg surface and fine-wire electromyographic activity was recorded simultaneously during gait to assess if electrode type (fine-wire vs. surface) affects muscle onset, time to peak, peak amplitude, and activation patterns. No significant differences were recorded between surface and fine-wire electrodes for muscle onset or time to peak activation. Activation patterns revealed similarity between electrodes. Some significant differences were detected in peak amplitude. Non-invasive surface electrodes provide an adequate representation of timing variables for primary ankle muscles during gait.

Tuck Jump Assessment: An Exploratory Factor Analysis in a College Age Population

Abstract Lininger, MR, Smith, CA, Chimera, NJ, Hoog, P, and Warren, M. Tuck Jump Assessment: An exploratory factor analysis in a college age population. J Strength Cond Res 31(3): 653–659, 2017—Due to the high rate of noncontact lower extremity injuries that occur in the collegiate setting, medical personnel are implementing screening mechanisms to identify those athletes that may be at risk for certain injuries before starting a sports season. The tuck jump assessment (TJA) was created as a “clinician friendly” tool to identify lower extremity landing technique flaws during a plyometric activity. There are 10 technique flaws that are assessed as either having the apparent deficit or not during the TJA. Technique flaws are then summed up for an overall score. Through expert consensus, these 10 technique flaws have been grouped into 5 modifiable risk factors: ligament dominance, quadriceps dominance, leg dominance or residual injury deficits, trunk dominance (“core” dysfunction), and technique perfection. Research has not investigated the psychometric properties of the TJA technique flaws or the modifiable risk factors. The present study is a psychometric analysis of the TJA technique flaws to measure the internal structure using an exploratory factor analysis (EFA) using data from collegiate athletes (n = 90) and a general college cohort (n = 99). The EFA suggested a 3 factor model accounting for 46% of the variance. The 3 factors were defined as fatigue, distal landing pattern, and proximal control. The results differ from the 5 modifiable risk categories as previously suggested. These results may question the use of a single score, a unidimensional construct, of the TJA for injury screening.