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Context: Nordic hamstring strength (NH strength) and single leg bridge test (SLBT) scores are used to predict the risk of hamstring strain injury. Although NH strength and SLBT scores may be related, the relationship between NH strength and SLBT score remains unknown. Objectives: This study investigated the relationship between NH strength and SLBT scores in university soccer players. Design: Cross-sectional study. Setting: Research laboratory. Participants: 38 male university soccer players. Main Outcome Measures: NH strength and SLBT scores. Interventions: A participant was instructed to lean forward gradually at the slowest possible speed from a kneeling posture with the knee joint flexed 90° for the NH strength measurement. Participants in the SLBT crossed their arms over their chests, pushed down from their heels, and lifted their hips off the ground as many times as they could until they failed. We investigated the relationship between NH strength and SLBT scores in the left and right sides using Spearman rank correlation coefficient. Additionally, we calculated the percentage of left–right asymmetry in NH strength and SLBT scores and investigated the relationship between these variables using Pearson correlation coefficient. Results: There were no significant correlations between NH strength and SLBT scores in the right (r _s  = .239, P = .16) and left (r _s  = .311, P = .065) legs. Furthermore, there was no significant relationship between NH strength and SLBT between-limb asymmetry (r = .073, P = .671). Conclusions: NH strength and SLBT scores could be different indexes, indicating either maximal muscle strength or muscle endurance. Thus, the findings suggested that when assessing risk factors for hamstring strain injury, both NH strength and SLBT scores should be measured.

Clinical Scenario: Hamstring range of motion (ROM) and the influence it has on injury risk is among great discussion in the literature. Hamstring injury may result from hamstring tightness, poor flexibility, or decreased ROM, and many argue that this can be prevented through various intervention strategies. In active populations, risk of further injury, pain, and complications throughout the kinetic chain can occur if minimal hamstring ROM is left untreated. One therapeutic intervention that has been applied to varying parts of the body to help improve function while relieving pain is dry needling (DN). This intervention includes the application of needles to structures to induce responses that might benefit healing and overall stimulation of a neurological response. In this review, the intent is to identify evidence and the effects of DN on hamstring ROM. Clinical Question: What are the effects of DN on hamstring ROM? Summary of Key Findings: Among total 11 articles, 1 single-blinded randomized controlled trial and 2 double-blinded randomized controlled trials were included in this critically appraised topic. All 3 articles had inconclusive evidence to isolate the application of the DN intervention. There was insufficient evidence to identify if DN independently improved hamstring ROM; however, in combination with interventions such as exercise and stretch plans, there were improvements on ROM. Clinical Bottom Line: DN does not significantly increase or decrease the ROM of the hamstrings. When combined with exercise and stretch plans, DN could increase ROM. Strength of Recommendation: The grade of B is recommended by the Strength of Recommendation Taxonomy for inconsistent or limited-quality patient-oriented evidence.

Context: Single- and dual-task walking gait assessments have been used to identify persistent movement and cognitive dysfunction among athletes with concussions. However, it is unclear whether previous ankle sprain injuries confound these outcomes during baseline testing. The purpose of this study was to determine the effects of (1) ankle sprain history and (2) time since prior ankle sprain injury on single- and dual-task spatiotemporal gait outcomes and cognitive measures. Design: Cross-sectional study. Methods: We assessed 60 college Division-I athletes (31 with ankle sprain history; 13 females and 18 males, 19.3 [0.8] y; 29 with no ankle sprain history, 14 females and 15 males, 19.7 [0.9] y) who completed injury history forms and underwent concussion baseline testing. Athletes completed single- and dual-task gait assessments by walking back and forth along an 8-m walkway for 40 seconds. Athletes wore a smartphone with an associated mobile application on their lumbar spine to record spatiotemporal gait parameters and dual-task cognitive performance. Separate multivariate analyses of variance were used to assess the effects of ankle sprain injury history on spatiotemporal measures, gait variability, and cognitive performance. We performed a multivariate regression subanalysis on athletes who reported time since injury (n = 23) to assess temporal effects on gait and cognitive performance. Results: Athletes with and without a history of ankle sprains had comparable spatiotemporal and gait variability outcomes during single- (P = .42; P = .13) and dual-task (P = .75; P = .55) conditions. Additionally, ankle sprain injury history did not significantly influence cognitive performance (P = .35). Finally, time since ankle sprain did not significantly affect single- (P = .75) and dual-task gait (P = .69), nor cognitive performance (P = .19). Conclusions: Ankle sprain injury history did not significantly alter spatiotemporal gait outcomes nor cognitive performance during this common clinical assessment. Future studies may consider including athletes with ankle sprain injury history during concussion assessments.

Clinical Scenario: Exercise-associated muscle cramps (EAMC) are sudden, painful, and involuntary contractions of skeletal muscles during or after physical activity. The best treatment for EAMC is gentle static stretching until abatement. Stretching is theorized to relieve EAMC by normalizing alpha motor neuron control, specifically by increasing Golgi tendon organ activity, and physically separating contractile proteins. However, it is unclear if stretching or flexibility training prevents EAMC via the same mechanisms. Despite this, many clinicians believe prophylactic stretching prevents EAMC occurrence. Clinical Question: Do athletes who experience EAMC during athletic activities perform less prophylactic stretching or flexibility training than athletes who do not develop EAMC during competitions? Summary of Key Findings: In 3 cohort studies and 1 case-control study, greater preevent muscle flexibility, stretching, or flexibility training (ie, duration, frequency) was not predictive of who developed EAMC during competition. In one study, athletes who developed EAMC actually stretched more often and 9 times longer (9.8 [23.8] min/wk) than noncrampers (1.1 [2.5] min/wk). Clinical Bottom Line: There is minimal evidence that the frequency or duration of prophylactic stretching or flexibility training predicts which athletes developed EAMC during competition. To more effectively prevent EAMC, clinicians should identify athletes’ unique intrinsic and extrinsic risk factors and target those risk factors with interventions. Strength of Recommendation: Minimal evidence from 3 prospective cohort studies and 1 case-control study (mostly level 3 studies) that suggests prophylactic stretching or flexibility training can predict which athletes develop EAMC during athletic competitions.

Clinical Scenario: Achilles tendon ruptures are prevalent and devastating injuries that require the need for extensive rehabilitation. The methods for preventing these injuries vary between different exercise methods and nutritional supplementation. Although proven effective for decreasing pain and increasing tendon properties, the influence of these 2 methods in combination has not yet been evaluated. Clinical Question: Does exercise combined with collagen supplementation improve Achilles tendon structural and mechanical properties and diminish subsequent patient-reported pain compared with exercise alone in adults? Summary of Key Findings: Exercise training, including eccentric training protocols and concentric resistance training protocols, combined with collagen supplementation influence Achilles tendon properties and subsequent patient-reported pain compared with exercise alone. Clinical Bottom Line: Evidence supports that collagen along with exercise training has a significant influence on pain mitigation, augmented cross-sectional area, and tendon thickness, but may have little to no influence on tendon stiffness and microvascularity compared with exercise alone. Further research is needed to determine the effects of combined methods on various populations. Strength of Recommendation: Collectively, the body of evidence included to answer the clinical question aligns with the strength of recommendation of A.

Context: Hip and groin injuries are common in field sports such as football, with measurement of hip strength and range of motion (ROM) recommended for assessment of these conditions. We aimed to report hip strength, hip ROM, and functional task performance in young elite Australian football athletes. Design: Cross-sectional study. Methods: Fifty-eight newly drafted Australian Football League athletes completed hip abduction, adduction, internal rotation, external rotation, and flexion strength testing with an adjustable stabilized or hand-held dynamometer. Hip internal rotation and external rotation, bent knee fall out, and ankle dorsiflexion ROM were also measured. Players completed hop for distance, side bridge, and star excursion balance functional tests. We compared findings between the dominant and nondominant limbs. Results: We found small deficits unlikely to be clinically meaningful in the dominant limb for hip abduction and adduction strength, and a small deficit in the nondominant limb for external rotation strength and side bridge time. Athletes had lower hip internal rotation (mean difference 2.56°; 95% confidence interval, 0.87 to 4.26) and total rotation ROM (2.03°; 95% confidence interval, 0.06 to 4.01) on the dominant limb. Conclusions: There were no meaningful differences between dominant and nondominant limbs for hip strength, ROM, or functional tests. Our results may be used for benchmarking young male Australian football athletes when targeting optimal strength and returning from injury.

Clinical Scenario: Dancing is a demanding esthetic activity with dancers having an 85% annual injury incident rate when performing complex dance motor skills. Teachers and clinicians use a combination of external and internal attentional cues when teaching dancers motor skills and when working on rehabilitation programs with injured dancers, respectively. External attentional focus (ie, focusing on movement outcome) reportedly results in superior performance than internal attentional focus (ie, focus on body movements). Interestingly, dancers reportedly often adopt an internal focus when dancing. Still, limited literature exists examining the effects of attentional focus on dancers’ performance. Clinical Question: How does attentional focus (external or internal) impact performance in dancers? Summary of Key Findings: Four original quasi-experimental studies met inclusion criteria. In the current examination, we found mixed results about the impact of attentional focus in dancers. Specifically, using an external attentional focus resulted in better performance in 2 studies, but these findings were limited to lesser experienced dancers. Experienced dancers did not have any physical performance differences when using external or internal focus. Internal focus also did not negatively affect dancers’ performance in 2 studies. Some authors noted positive motivational effects (eg, increased perceived competence) when dancers used external focus. Clinical Bottom Line: Low-quality evidence exists supporting the notion that in less experienced dance students, external focus improves performance. In experienced dancers, the type of attentional focus did not impact performance. External focus provides positive mental effects. Thus, clinicians working with dancers can integrate individualized feedback according to dancer level, with a preference toward external focus due to positive mental effects, to design optimal training and rehabilitation programs. Strength of Recommendation: Grade B evidence exists supporting the notion that an external attentional focus improves performance in less experienced dance students and also has positive mental effects. Internal attentional focus does not impede experienced dancers’ performance.

Context: The utility of baseline vestibular and ocular motor screening (VOMS) in high school and collegiate athletes is demonstrated throughout the literature; however, baseline VOMS data at the youth level are limited. In addition, with the recent adoption of the change scoring method, there is a need to document baseline VOMS total and change scores in a pediatric population. Objective: To document baseline VOMS total and change scores and to document the internal consistency of the VOMS in pediatric soccer athletes. We hypothesized that the VOMS would demonstrate strong internal consistency in pediatric soccer athletes. Design: Cross-sectional study. Methods: Pediatric soccer athletes (N = 110; range = 5–12 y) completed the VOMS at baseline. Descriptive statistics summarized demographic information, VOMS total scores, and VOMS change scores. Cronbach α assessed internal consistency for VOMS total scores and change scores. Results: Twenty-one (19.1%) participants had at least one total score above clinical cutoffs (≥2 on any VOMS component and ≥5 cm on average near point convergence). Forty (36.4%) participants had at least one change score above clinical cutoffs (≥1 on any VOMS component and ≥3 cm on average near point convergence). The internal consistency was strong for total scores with all VOMS components included (Cronbach α = .80) and change scores (Cronbach α = .89). Conclusions: Although results suggest VOMS items measure distinct components of the vestibular and ocular motor systems, caution should be taken when interpreting VOMS total and change scores in pediatric athletes, as overreporting symptoms is common, thereby impacting the false-positive rate.

Context: There are no available questionnaires in Spanish that assess the function and performance of shoulder and elbow in overhead sports. The Kerlan-Jobe Orthopaedic Clinic (KJOC) score is a reference tool for this purpose. We aimed to cross-culturally adapt and investigate its measurement properties in Spanish overhead athletes. Design: Cross-cultural adaptation followed the steps of direct translation, back translation, comprehensibility analysis, and review by the Committee of Experts. Then, symptomatic and asymptomatic overhead athletes were invited to complete an electronic version of the Spanish adaptation (KJOC-Sp). The structural validity was evaluated through an exploratory factor analysis with principal axis factoring. Hypotheses were tested for known-groups and convergent validity, studying the correlation with the Shoulder Pain and Disability Index and the Disabilities of the Arm, Shoulder, and Hand Sports Module questionnaires in symptomatic athletes. Cronbach alpha was calculated for internal consistency and intraclass correlation coefficient (ICC)_2,1 for test–retest reliability. Floor and ceiling effects and time to completion were also calculated. Results: The KJOC-Sp maintained the content of the original version and was adapted to the new population. One hundred participants (41 females and 59 males) with a mean age of 22.4 (5.9) years participated in the study of measurement properties. The factor analysis revealed a 1-factor solution. Symptomatic participants scored significantly lower than asymptomatic, with a large effect size (P < .001; r = .67). Correlations were of −.60 (P < .05) with the Shoulder and Pain Disability Index questionnaire and −0.66 (P < .05) with the Disabilities of the Arm, Shoulder, and Hand Sports Module questionnaire. Cronbach alpha was .98 (95% confidence interval, .97–.98) and the ICC_2,1 was .96 (95% confidence interval .93–.98). No floor or ceiling effects were observed among the symptomatic athletes, while mean time to completion was 121 seconds. Conclusion: The KJOC-Sp is equivalent to the original score, aside from valid and reliable, without floor or ceiling effects in symptomatic athletes and with a low time consumption.

Clinical Scenario: Injuries that affect the groin region are among the most common in football players. To prevent this condition, studies have focused on strengthening the adductors, hip flexors, or abdominal muscles. Recent investigations have used an eccentric-biased exercise (Copenhagen Adduction Exercise [CAE]) that promotes functional and architectural adaptations in the muscle tissue, though its effect on injury risk reduction is unknown. Clinical Question: Can the Copenhagen Adduction Exercise prevent groin injuries in soccer players? Summary of Key Findings: The literature was searched for studies investigating the potential groin injury risk reduction effect of the CAE. (1) Three studies met the inclusion criteria and were used for this appraisal; (2) one study observed a significantly lower injury rate ratio favoring the group that used the CAE program; and (3) 2 studies found similar or higher injury rates in the intervention groups, not supporting the inclusion of the CAE as a preventative tool. Clinical Bottom Line: There is conflicting evidence that usage of the CAE is superior to not performing adductor strengthening exercises in mitigating the risk of sustaining groin injuries. Given the evidence supporting these findings, it is advisable to exercise caution when contemplating the incorporation of the CAE into training regimens aimed at preventing groin injuries. Strength of Recommendation: There is Grade B evidence to suggest that inclusion of the CAE may not be associated with reduced injury rates.