Salivary microRNA as a prospective tool for concussion diagnosis and management: A scoping review.

BACKGROUND: Despite increased efforts directed toward research, concussions are a growing concern and can be a complex injury for healthcare professionals to manage. Current practices are largely dependent on patients self-reporting symptoms and a clinical assessment, which uses objective tools that lack effectiveness. With the demonstrated effects of concussions, it is imperative that a more valid or reliable objective tool, like a clinical biomarker, be identified to improve outcomes. One potential biomarker that has shown promise is salivary microRNA. However, there is no objective consensus as to which microRNA offers the most clinical value regarding concussions, hence this review. Therefore, the purpose of this scoping review was to identify salivary miRNAs associated with concussions. METHODS: Two independent reviewers performed a literature search to identify research articles. Studies using human subjects, collected salivary miRNA, and were published in English were included. Data of interest were salivary miRNA, collection timing, and relation to concussion diagnosis or management. RESULTS: This paper reviews nine studies that analyzed salivary miRNA for concussion diagnosis and management. CONCLUSIONS: In total, the studies have identified 49 salivary miRNA that show promise in assisting with concussion practices. With continued research, the use of salivary miRNA may enhance clinicians' abilities to diagnose and manage concussions.

Perceived Instability, Pain, and Psychological Factors for Prediction of Function and Disability in Individuals With Chronic Ankle Instability.

CONTEXT: Chronic ankle instability (CAI) is associated with residual instability, pain, decreased function, and increased disablement. Injury-related fear has been associated with CAI, although its relationship to other impairments is unclear. The fear-avoidance model is a theoretical framework hypothesizing a relationship among pain catastrophizing, injury-related fear, chronic pain, and disability. It has been useful in understanding fear's influence in other musculoskeletal conditions but has yet to be studied in those with CAI. OBJECTIVE: To explore relationships among instability, pain catastrophizing, injury-related fear, pain, ankle function, and global disability in individuals with CAI. DESIGN: Cross-sectional study. SETTING: Anonymous online survey. PATIENTS OR OTHER PARTICIPANTS: A total of 259 people, recruited via email and social media, with a history of ankle sprain completed the survey; of those, 126 participants (age = 32.69 ± 4.38 years, females = 84.92%, highly active = 73.81%) were identified as having CAI and were included in the analysis. MAIN OUTCOME MEASURE(S): Demographics of gender identity, age, and physical activity level were recorded. Assessments used were the Identification of Functional Ankle Instability questionnaire (instability), the Pain Catastrophizing Scale (pain catastrophizing), the Tampa Scale of Kinesiophobia-11 (injury-related fear), a numeric pain rating scale and activity-based question (pain presence), the Quick Foot and Ankle Ability Measure (ankle function), and the modified Disablement in the Physically Active Scale (disability). Relationships among variables were explored through correlation and regression analyses. RESULTS: After we controlled for instability and pain, pain catastrophizing and injury-related fear were significantly related to function and disability ratings in individuals with CAI. Together, the variables predicted 48.7% (P < .001) of the variance in function and 44.2% (P < .001) of the variance in disability. CONCLUSIONS: Greater instability, pain catastrophizing, injury-related fear, and pain predicted decreased function and greater disability in those with CAI. These findings are consistent with the hypothesized relationships in the fear-avoidance model, although further investigation is needed to determine causality of these factors in the development of CAI.

The relationship between single-limb squat and jump-cut kinematics.

No objective criteria exist for progressing athletes into cutting manoeuvres following ACL reconstruction (ACLR). The purpose of this study was to evaluate the relationship between a jump-cut task (JC) and the single-limb squat (SLS) in both ACLR and healthy controls. Case-control, laboratory based. Twenty-three participants with a history of ACLR (Age = 21 ± 3 years; Height = 174.5 ± 7.2 cm; Mass = 76.2 ± 9.9 kg) and 23 healthy controls participants (Age = 21 ± 3 years; Height = 173.8 ± 9.2 cm; Mass = 75.0 ± 10.5 kg) were included. Kinematics were collected bilaterally. Correlations between tasks were evaluated for kinematics. Independent sample t-tests were used to evaluate differences between groups for each dependent variable. Peak trunk rotation and medial knee displacement were strongly correlated (p < 0.001, r2 = 0.63), between tasks. ACLR group performed SLS and JC tasks with less sagittal plane motion compared to healthy controls (p < 0.05). Lack of frontal and transverse plane control during SLS resulted in positions of increased lateral trunk flexion, hip adduction, and medial knee displacement during JC. The SLS may be considered for use as a clinical predictor of JC during rehabilitation following ACLR.

Preventive Training Program Feedback Complexity, Movement Control, and Performance in Youth Athletes.

CONTEXT: Preventive training programs (PTPs) reduce injury risk by improving movement control. Corrective feedback is important; however, many cues at once may be too complicated for athletes. OBJECTIVE: To compare movement control and long-jump (LJ) changes in youth athletes participating in a season-long PTP, with simplified feedback, traditional feedback, or a warmup of the coaches' choosing. DESIGN: Cluster-randomized controlled trial. SETTING: Soccer fields. PATIENTS OR OTHER PARTICIPANTS: A total of 420 athletes (simplified feedback = 173, traditional feedback = 118, and control = 129; age = 11 ± 3 years). INTERVENTION(S): Teams were randomized into the simplified PTP, traditional PTP, or control group. Simplified and traditional PTPs lasted 10 to 12 minutes and used the same exercises. The simplified PTP provided only sagittal-plane feedback (eg, "get low"), and the traditional PTP provided feedback targeting all motion planes (eg, "don't let your knees cave inward"). Research assistants administered the PTP warmups 2 to 3 times/week for the season. Control team coaches chose and ran their own warmup strategies. MAIN OUTCOME MEASURE(S): Participants completed 4 sessions (preseason [PRE], postseason [POST] at approximately 8 weeks after PRE, retention 1 [R1] at 6 weeks postseason, and retention 2 [R2] at 12 weeks postseason). They performed 3 trials of a jump-landing task, which was evaluated using the Landing Error Scoring System (LESS) and 2 recorded standing LJ trials at each test session. A time series panel was used to evaluate group differences across time points for the LESS and LJ. RESULTS: Change score analyses revealed improvements in the LESS score from PRE to POST for all groups. Improvements from PRE were retained at R1 and R2 for the intervention groups (simplified and traditional). The traditional group demonstrated better LJ performance at POST (P < .001) and R1 (P = .049) than the simplified or control group. CONCLUSIONS: Simplified cues were as effective as traditional cues in improving LESS scores from PRE to POST season. Participating in PTPs, regardless of their complexity, likely provides movement benefits.

Sport Sampling Is Associated With Improved Landing Technique in Youth Athletes.

BACKGROUND: Sport sampling is recommended to promote fundamental movement skill acquisition and physical activity. In contrast, sport specialization is associated with musculoskeletal injury risk, burnout, and attrition from sport. There is limited evidence to support the influence of sport sampling on neuromuscular control, which is associated with injury risk, in youth athletes. HYPOTHESIS: Athletes who participated in only 1 sport during the previous year would demonstrate higher Landing Error Scoring System (LESS) scores than their counterparts. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 355 youth athletes (age range, 8-14 years) completed a test session with a jump-landing task, which was evaluated using the LESS. Participants were categorized as single sport (SS) or multisport (MS) based on their self-reported sport participation in the past year. Their duration of sport sampling (low, moderate, high) was determined based on their sport participation history. Participants were dichotomized into good (LESS <5) or poor (LESS ≥5) categories. Chi-square tests were performed to evaluate for the association between control category (good, poor) and participation (MS, SS), as well as sport-sampling duration (low, moderate, high). RESULTS: The MS group was 2.5 times (95% CI, 1.9-3.1) as likely to be categorized as having good control compared with the SS group (χ2(355) = 10.10, P < 0.01). Recreational participants in the "high" sport-sampling duration group were 5.8 times (95% CI, 3.1-8.5) and 5.4 times (95% CI, 4.0-6.8) as likely to be categorized as having good control compared with the moderate and low groups (χ2(216) = 11.20, P < 0.01). CONCLUSION: Sport sampling at a young age is associated with improved neuromuscular control, which may reduce injury risk in youth athletes. CLINICAL RELEVANCE: Youth athletes should be encouraged to try participating in multiple sports to enhance their neuromuscular control and promote long-term physical activity.

Effect of a Lower Extremity Preventive Training Program on Physical Performance Scores in Military Recruits.

Peck, KY, DiStefano, LJ, Marshall, SW, Padua, DA, Beutler, AI, de la Motte, SJ, Frank, BS, Martinez, JC, and Cameron, KL. Effect of a lower extremity preventive training program on physical performance scores in military recruits. J Strength Cond Res 31(11): 3146-3157, 2017-Exercise-based preventive training programs are designed to improve movement patterns associated with lower extremity injury risk; however, the impact of these programs on general physical fitness has not been evaluated. The purpose of this study was to compare fitness scores between participants in a preventive training program and a control group. One thousand sixty-eight freshmen from a U.S. Service Academy were cluster-randomized into either the intervention or control group during 6 weeks of summer training. The intervention group performed a preventive training program, specifically the Dynamic Integrated Movement Enhancement (DIME), which is designed to improve lower extremity movement patterns. The control group performed the Army Preparation Drill (PD), a warm-up designed to prepare soldiers for training. Main outcome measures were the Army Physical Fitness Test (APFT) raw and scaled (for age and sex) scores. Independent t tests were used to assess between-group differences. Multivariable logistic regression models were used to control for the influence of confounding variables. Dynamic Integrated Movement Enhancement group participants completed the APFT 2-mile run 20 seconds faster compared with the PD group (p < 0.001), which corresponded with significantly higher scaled scores (p < 0.001). Army Physical Fitness Test push-up scores were significantly higher in the DIME group (p = 0.041), but there were no significant differences in APFT sit-up scores. The DIME group had significantly higher total APFT scores compared with the PD group (p < 0.001). Similar results were observed in multivariable models after controlling for sex and body mass index (BMI). Committing time to the implementation of a preventive training program does not appear to negatively affect fitness test scores.

Coach-led preventive training program in youth soccer players improves movement technique.

Long-term implementation of preventive training programs (PTP) in youth sport requires coach involvement. However, the optimal training of coaches to effectively implement a PTP remains unknown. It is also unknown if the benefits of PTP can be enhanced with multiple sport seasons of exposure. OBJECTIVES: To evaluate the influence of prior PTP exposure on movement technique in youth soccer players after completing a coach-led PTP. DESIGN: Cluster-randomized controlled trial. METHODS: Twelve youth soccer teams (n=89; age range 8-14 years) were divided into groups with (Experience (EXP); 6 teams [n=18 females, n=25 males]) and without (Novice (NOV); 6 teams [n=30 females, n=16 males]) previous professional-led PTP experience. The coaches and players of the EXP teams were exposed to an eight-week professional-led PTP before the coach-led PTP. EXP and NOV coaches attended the educational workshop prior to implementing the coach-led PTP. The Landing Error Scoring System (LESS) was used to evaluate movement technique. RESULTS: Both groups improved LESS scores over time (mean difference±SD [post-pre]=-0.8±0.2, 95%CI [-1.2, -0.4], p=0.0001). Of the 64 participants classified as high risk for injury (LESS ≥5) prior to PTP implementation, a greater proportion of EXP (n=14) compared to NOV (n=7) participants changed risk classification from high to low (LESSΔ≥1 and LESS <5; p=0.03). CONCLUSIONS: Our PTP enhanced movement technique regardless of PTP experience, but the benefits of the PTP impacted a proportionally greater number of players with previous PTP experience supporting continued PTP implementation. Coaches effectively implemented an exercise-based PTP after attending a training workshop regardless of previous PTP experience.

Landing Technique Improvements After an Aquatic-Based Neuromuscular Training Program in Physically Active Women.

CONTEXT: Neuromuscular training programs (NTPs) improve landing technique and decrease vertical ground-reaction forces (VGRFs), resulting in injury-risk reduction. NTPs in an aquatic environment may elicit the same improvements as land-based programs with reduced joint stress. OBJECTIVE: To examine the effects of an aquatic NTP on landing technique as measured by the Landing Error Scoring System (LESS) and VGRFs, immediately and 4 mo after the intervention. DESIGN AND SETTING: Repeated measures, pool and laboratory. PARTICIPANTS: Fifteen healthy, recreationally active women (age 21 ± 2 y, mass 62.02 ± 8.18 kg, height 164.74 ± 5.97 cm) who demonstrated poor landing technique (LESS-Real Time > 4). INTERVENTIONS: All participants completed an aquatic NTP 3 times/wk for 6 wk. MAIN OUTCOME MEASURES: Participants' landing technique was evaluated using a jump-landing task immediately before (PRE), immediately after (POST), and 4 mo after (RET) the intervention period. A single rater, blinded to time point, graded all videos using the LESS, which is a valid and reliable movement-screening tool. Peak VGRFs were measured during the stance phase of the jump-landing test. Repeated-measure analyses of variance with planned comparisons were performed to explore differences between time points. RESULTS: LESS scores were lower at POST (4.46 ± 1.69 errors) and at RET (4.2 ± 1.72 errors) than at PRE (6.30 ± 1.78 errors) (P < .01). No significant differences were observed between POST and RET (P > .05). Participants also landed with significantly lower peak VGRFs (P < .01) from PRE (2.69 ± .72 N) to POST (2.23 ± .66 N). CONCLUSIONS: The findings introduce evidence that an aquatic NTP improves landing technique and suggest that improvements are retained over time. These results show promise of using an aquatic NTP when there is a desire to reduce joint loading, such as early stages of rehabilitation, to improve biomechanics and reduce injury risk.

Female adolescent athletes' attitudes and perspectives on injury prevention programs.

OBJECTIVES: To examine what factors influence a high school female athlete's stated willingness to perform a lower extremity injury prevention program (IPP). A secondary aim was to examine if a participant's stated willingness affected her compliance with an IPP. DESIGN: Repeated measures. METHODS: We surveyed high school female field hockey, soccer and volleyball athletes before and after a season-long IPP warm-up intervention. Participants completed the Injury Prevention Program Attitude Survey (IPPAS), a paper and pencil survey utilizing Likert-style and open-ended questions. It was used to assess the athletes' willingness to perform an IPP if the data proved the player would experience improved performance, fewer injuries and risk factors, what outside factors influence their willingness to perform an IPP, who they would feel comfortable leading their team in an IPP, and what they believe an IPP can improve. RESULTS: Participants responded that they were willing to perform an IPP if data proved that they would have fewer injury risk factors (p≤0.001) and be less likely to suffer an ACL injury (p<0.001). Improved sport performance did not play a role in participants' willingness to perform an IPP. Before and after the warm-up intervention, participants stated that stretching, strengthening, and cardiovascular activity should be included in an IPP. Participants' stated willingness and beliefs prior to the intervention did not appear to affect their compliance. CONCLUSIONS: Female adolescent athletes are willing to perform IPPs if data indicated that they would have fewer injury risk factors and suffer fewer ACL and leg injuries.

The Effects of an Injury Prevention Program on Landing Biomechanics Over Time.

BACKGROUND: Knowledge is limited regarding how long improvements in biomechanics remain after completion of a lower extremity injury prevention program. PURPOSE: To evaluate the effects of an injury prevention program on movement technique and peak vertical ground-reaction forces (VGRF) over time compared with a standard warm-up (SWU) program. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 1104 incoming freshmen (age range, 17-22 years) at a military academy in the United States volunteered to participate. Participants were cluster-randomized by military company to either the Dynamic Integrated Movement Enhancement (DIME) injury prevention program or SWU. A random subsample of participants completed a standardized jump-landing task at each time point: immediately before the intervention (PRE), immediately after (POST), and 2 (POST2M), 4 (POST4M), 6 (POST6M), and 8 months (POST8M) after the intervention. VGRF data collected during the jump-landing task were normalized to body weight (%BW). The Landing Error Scoring System (LESS) was used to evaluate movement technique during the jump landing. The change scores (Δ) for each variable (LESS, VGRF) between the group's average value at PRE and each time point were calculated. Separate univariate analyses of variance were performed to evaluate group differences. RESULTS: The results showed a greater decrease in mean (±SD) VGRF in the DIME group compared with the SWU group at all retention time points: POST2M (SWU [Δ%BW], -0.13 ± 0.82; DIME, -0.62 ± 0.91; P = .001), POST4M (SWU, -0.15 ± 0.98; DIME,-0.46 ± 0.64; P = .04), POST6M (SWU, -0.04 ± 0.96; DIME, -0.53 ± 0.83; P = .004), and POST8M (SWU, 0.38 ± 0.95; DIME, -0.11 ± 0.98; P = .003), but there was not a significant improvement in the DIME group between PRE and POST8M (Δ%BW, -0.11 ± 0.98). No group differences in Δ LESS were observed. CONCLUSION: The study findings demonstrated that an injury prevention program performed as a warm-up can reduce vertical ground-reaction forces compared with a standard warm-up but a maintenance program is likely necessary in order for continued benefit. CLINICAL RELEVANCE: Injury prevention programs may need to be performed constantly, or at least every sport season, in order for participants to maintain the protective effects against injury.

Maturation and Sex Differences in Neuromuscular Characteristics of Youth Athletes.

Understanding how neuromuscular factors that are associated with lower extremity injury risk, such as landing kinematics, muscle strength, and flexibility, change as children mature may enhance age-specific recommendations for injury prevention programs. The purpose of this study was to compare these factors in prepubertal, pubertal, and postpubertal male and female athletes. Subjects were classified on maturation stage (prepubertal: 16 males, 15 females, age: 9 ± 1 years; pubertal: 13 males, 12 females, age: 12 ± 3 years; postpubertal: 30 males, 27 females, age: 16 ± 2 years). Researchers measured lower extremity isometric muscle strength and flexibility and evaluated kinematics and vertical ground reaction forces (VGRFs) during a jump-landing task. Three-dimensional kinematics at initial contact (IC), joint displacements, and peak VGRF were calculated. Separate multivariate analyses of variance were performed to evaluate sex and maturation differences (α ≤ 0.05). Postpubertal females landed with less knee flexion at IC (p = 0.006) and demonstrated lower knee extension strength (p = 0.01) than prepubertal and pubertal females. Postpubertal males landed with less hip adduction displacement (postpubertal males = 12.53 ± 6.15°, prepubertal males = 18.84 ± 7.47°; p = 0.04) and less peak VGRF (postpubertal males = 1.53 ± 0.27% body weight [BW], prepubertal males = 1.99 ± 0.32% BW; p = 0.03) compared with prepubertal males. These findings suggest encouraging sagittal plane absorption and decreasing frontal plane motion at the hip, whereas maintaining quadriceps strength may be important for reducing injury risk in postpubertal athletes.

Health-related quality of life differs between adolescent athletes and adolescent nonathletes.

CONTEXT: Patient-oriented outcome measures such as the Medical Outcomes Short Form (SF-36) and the Pediatric Outcomes Data Collection Instrument (PODCI) are important tools for determining the impact of events like sport-related injury on health-related quality of life (HRQoL). Unfortunately, there are no published studies using these instruments that compare adolescent athletes with their nonathlete peers, making interpretations of these measures in this population difficult. OBJECTIVE: To compare HRQoL in adolescent athletes and nonathletes using 2 common instruments. DESIGN: Cross-sectional. SETTING: 7 high schools. PARTICIPANTS: 219 athletes and 106 nonathletes. INTERVENTION: None. MAIN OUTCOME MEASURES: The SF-36 and the PODCI were completed in a counterbalanced manner during 1 session. Dependent variables included the 8 subscale and 2 composite scores of the SF-36 and the 5 subscale scores and 1 global score of the PODCI. RESULTS: On the SF-36, athletes reported higher scores on the physical function, general health, social functioning, and mental health subscales and the mental composite score and lower scores on the bodily pain subscale than nonathletes. On the PODCI, athletes reported higher scores on the sport and physical function and happiness subscales and lower scores on the pain/comfort subscale. CONCLUSIONS: Athletes reported higher scores on a number of SF-36 and PODCI subscales related to mental, emotional, and physical well-being than nonathletes. Our findings suggest that athletic involvement may be a benefit to the overall health status of adolescents and imply that athletes may be a distinct adolescent group requiring their own normative values when using the SF-36 and PODCI.