Context: Nordic hamstring exercise (NHE) has been widely employed to prevent hamstring strain injuries. However, it is still not clear which adaptations are responsible for the NHE preventive effects. Objectives: The aim of this study was to investigate the effects of NHE on knee flexors eccentric strength and fascicle length. Evidence Acquisition: The search strategy included MEDLINE, PEDro, and Cochrane CENTRAL from inception to April 2020. Randomized clinical trials that have analyzed the effects of NHE training on hamstring eccentric strength and/or fascicle length were included. Evidence Synthesis: From the 1932 studies identified, 12 were included in the systematic review, and 9 studies presented suitable data for the meta-analysis. All studies demonstrated strength increments in response to NHE training (10%–15% and 16%–26% in tests performed on the isokinetic dynamometer and on the NHE device, respectively), as well as significant enhancement of biceps femoris long head fascicle length (12%–22%). Meta-analysis showed NHE training was effective to increase knee flexors eccentric strength assessed with both isokinetic tests (0.68; 95% confidence interval, 0.29 to 1.06) and NHE tests (1.11; 95% confidence interval, 0.62 to 1.61). NHE training was also effective to increase fascicle length (0.97; 95% confidence interval, 0.46 to 1.48). Conclusions: NHE training has the potential of increasing both knee flexors eccentric strength and biceps femoris long head fascicle length.
Diulian Muniz Medeiros, César Marchiori, and Bruno Manfredini Baroni
Chee Vang and Alexander Niznik
Clinical Scenario: Patellar tendinopathy is a common musculoskeletal disorder affecting the lower-extremities and a difficult condition to manage for athletes that are in season. To facilitate improvement in function and to decrease pain, initial treatment for patellar tendinopathy is typically conservative. Traditional interventions may include eccentric training, cryotherapy, patellar counterforce straps, oral anti-inflammatories, injectable agents, phonophoresis, iontophoresis, orthotics, therapeutic ultrasound, and extracorporeal shockwave. In addition, recent literature suggests that implementing isometric and isotonic contractions may be effective in reducing patellar tendon pain. Focused Clinical Question: How effective are isometric contractions compared with isotonic contractions in reducing pain for in-season athletes with patellar tendinopathy? Summary of Key Findings: Implementation of isometric and isotonic exercises statistically reduced pain levels in the short term of 4 weeks for in-season athletes; however, isometric contractions provided statistically greater pain relief immediately for up to 45 minutes postintervention compared with isotonic contractions. Clinical Bottom Line: Current evidence supports the use of isometric and isotonic contractions to reduce pain for in-season athletes with patellar tendinopathy. Based on the reviewed literature, clinicians should consider utilizing heavy loaded isometrics or progressive heavy loaded isotonic exercises, which showed reduction in pain levels immediately after intervention and at 4-week follow-up for both intervention groups. Isometric contractions appear to provide greater pain relief immediately after intervention. Strength of Recommendation: There is Grade B evidence from 2 level 2 randomized controlled trials and 1 level 3 randomized crossover study supporting the use of isometric and isotonic contractions to reduce patellar tendon pain for in-season athletes.
Katherine L. Helly, Katherine A. Bain, Phillip A. Gribble, and Matthew C. Hoch
Clinical Scenario: Patients with chronic ankle instability (CAI) demonstrate deficits in both sensory and motor function, which can be objectively evaluated through static postural control testing. One intervention that has been suggested to improve somatosensation and, in turn, static postural control is plantar massage. Clinical Question: Does plantar massage improve static postural control during single-limb stance in patients with CAI relative to baseline? Summary of Key Findings: A search was performed for articles exploring the effect of plantar massage on static postural control in individuals with CAI. Three articles were included in this critically appraised topic including 1 randomized controlled trial and 2 crossover studies. All studies supported the use of plantar massage to improve static postural control in patients with CAI. Clinical Bottom Line: There is currently good-quality and consistent evidence that supports the use of plantar massage as an intervention that targets the somatosensory system to improve static postural control in patients with CAI. Future research should focus on incorporating plantar massage as a treatment intervention during long-term rehabilitation protocols for individuals with CAI. Strength of Recommendation: In agreement with the Center of Evidence-Based Medicine, the consistent results from 2 crossover studies and 1 randomized controlled trial designate that there is level B evidence due to consistent, moderate- to high-quality evidence.
Mackenzie Holman, Madeline P. Casanova, and Russell T. Baker
Context: Patient-reported outcomes are widely used in health care. The Disablement in the Physically Active (DPA) Scale Short Form-8 (SF-8) was recently proposed as a valid scale for the physically active population. However, further psychometric testing of the DPA SF-8 has not been completed, and scale structure has not been assessed using a sample of adolescent athletes. Objective: To assess scale structure of the DPA SF-8 in a sample of adolescent high-school athletes. Main Outcome Measure(s): Adolescent athletes (n = 289) completed the DPA SF-8. Confirmatory factor analysis (CFA) was conducted to assess the psychometric properties of the scale. Results: The CFA of the DPA SF-8 indicated that the model exceeded recommended fit indices (Comparative Fit Index = .976, Tucker–Lewis Index = .965, Root Mean Square Error of Approximation = .061, and Bollen’s Incremental Fit Index = .976). All factor loadings were significant and ranged from .62 to .86. Modification indices did not suggest that meaningful cross-loadings were present or additional specifications that could further maximize fit or parsimony. Conclusions: The CFA of the DPA SF-8 met contemporary model fit recommendations in the adolescent athlete population. The results confirmed initial findings supporting the psychometric properties of the DPA SF-8 as well as the uniqueness of the quality-of-life and physical summary factors in an adolescent population. Further research (eg, reliability, invariance between groups, minimal clinically important differences, etc) is warranted to inform scale use in clinical practice and research.
Kate N. Jochimsen, Carl G. Mattacola, Brian Noehren, Kelsey J. Picha, Stephen T. Duncan, and Cale A. Jacobs
Context: Femoroacetabular impingement syndrome (FAIS) is a painfully debilitating hip condition disproportionately affecting active individuals. Mental health disorders are an important determinant of treatment outcomes for individuals with FAIS. Self-efficacy, kinesiophobia, and pain catastrophizing are psychosocial factors that have been linked to inferior outcomes for a variety of orthopedic conditions. However, these psychosocial factors and their relationships with mental health disorders, pain, and function have not been examined in individuals with FAIS. Objective: (1) To examine relationships between self-efficacy, kinesiophobia, pain catastrophizing, pain, and function in patients with FAIS and (2) to determine if these variables differ between patients with and without a self-reported depression and/or anxiety. Design: Cross-sectional. Setting: University health center. Participants: Fifty-one individuals with FAIS (42 females/9 males; age 35.7 [11.6] y; body mass index 27.1 [4.9] kg/m2). Main Outcome Measures: Participants completed the Pain Self-Efficacy Questionnaire, Tampa Scale for Kinesiophobia, Pain Catastrophizing Scale, visual analog scale for hip pain at rest and during activity, and the 12-item International Hip Outcome Tool. Self-reported depression and/or anxiety were recorded. The relationships between psychosocial factors, pain, and function were examined using Spearman rank-order correlations. Independent t tests and Mann–Whitney U tests were used to evaluate the effect of self-reported depression and/or anxiety on psychosocial factors, pain and function. Results: The 12-item International Hip Outcome Tool was correlated with pain during activity (ρ = −.57, P ≤ .001), Tampa Scale for Kinesiophobia (ρ = −.52, P ≤ .001), and Pain Self-Efficacy Questionnaire (ρ = .71, P ≤ .001). The Pain Self-Efficacy Questionnaire was also correlated with pain at rest (ρ = −.43, P = .002) and pain during activity (ρ = −.46, P = .001). Individuals with self-reported depression and/or anxiety (18/51; 35.3%) had worse self-efficacy and pain catastrophizing (P ≤ .01). Conclusion: Self-reported depression and/or anxiety, low self-efficacy, and high kinesiophobia were associated with more hip pain and worse function for patients with FAIS. These findings warrant further examination including psychosocial treatment strategies to improve the likelihood of a successful clinical outcome for this at-risk population.
Caitlin Brinkman, Shelby E. Baez, Carolina Quintana, Morgan L. Andrews, Nick R. Heebner, Matthew C. Hoch, and Johanna M. Hoch
Context: Fast visuomotor reaction time (VMRT), the time required to recognize and respond to sequentially appearing visual stimuli, allows an athlete to successfully respond to stimuli during sports participation, while slower VMRT has been associated with increased injury risk. Light-based systems are capable of measuring both upper- and lower-extremity VMRT; however, the reliability of these assessments are not known. Objective: To determine the reliability of an upper- and lower-extremity VMRT task using a light-based trainer system. Design: Reliability study. Setting: Laboratory. Patients (or Other Participants): Twenty participants with no history of injury in the last 12 months. Methods: Participants reported to the laboratory on 2 separate testing sessions separated by 1 week. For both tasks, participants were instructed to extinguish a random sequence of illuminated light-emitting diode disks, which appeared one at a time as quickly as possible. Participants were provided a series of practice trials before completing the test trials. VMRT was calculated as the time in seconds between target hits, where higher VMRT represented slower reaction time. Main Outcome Measures: Separate intraclass correlation coefficients (ICCs) with corresponding 95% confidence intervals (CIs) were calculated to determine test–retest reliability for each task. The SEM and minimal detectable change values were determined to examine clinical applicability. Results: The right limb lower-extremity reliability was excellent (ICC2,1 = .92; 95% CI, .81–.97). Both the left limb (ICC2,1 = .80; 95% CI, .56–.92) and upper-extremity task (ICC2,1 = .86; 95% CI, .65–.95) had good reliability. Conclusions: Both VMRT tasks had clinically acceptable reliability in a healthy, active population. Future research should explore further applications of these tests as an outcome measure following rehabilitation for health conditions with known VMRT deficits.
Nathan Waite, John Goetschius, and Jakob D. Lauver
Runners experience repeated impact forces during training, and the culmination of these forces can contribute to overuse injuries. The purpose of this study was to compare peak vertical tibial acceleration (TA) in trained distance runners on 3 surface types (grass, asphalt, and concrete) and 3 grades (incline, decline, and level). During visit 1, subjects completed a 1-mile time trial to determine their pace for all running trials: 80% (5%) of the average time trial velocity. During visit 2, subjects were outfitted with a skin-mounted accelerometer and performed 18 separate running trials during which peak TA was assessed during the stance phase. Each subject ran 2 trials for each condition with 2 minutes of rest between trials. Peak TA was different between decline (8.04 [0.12] g) and incline running (7.31 [0.35] g; P = .020). On the level grade, peak TA was greater during grass (8.22 [1.22] g) compared with concrete (7.47 [1.65] g; P = .017). On the incline grade, grass (7.68 [1.44] g) resulted in higher peak TA than asphalt (6.99 [1.69] g; P = .030). These results suggest that under certain grade conditions grass may result in higher TA compared with either concrete or asphalt.
Chung-Ju Huang, Hsin-Yu Tu, Ming-Chun Hsueh, Yi-Hsiang Chiu, Mei-Yao Huang, and Chien-Chih Chou
This study examined the effects of acute aerobic exercise on sustained attention and discriminatory ability of children with and without learning disabilities (LD). Fifty-one children with LD and 49 typically developing children were randomly assigned to exercise or control groups. The participants in the exercise groups performed a 30-min session of moderate-intensity aerobic exercise, whereas the control groups watched a running/exercise-related video. Neuropsychological tasks, the Daueraufmerksamkeit sustained attention test, and the determination tests were assessed before and after each treatment. Exercise significantly benefited performance in sustained attention and discriminatory ability, particularly in higher accuracy rate and shorter reaction time. In addition, the LD exercise group demonstrated greater improvement than the typically developing exercise group. The findings suggest that the acute aerobic exercise influenced the sustained attention and the discriminatory function in children with LD by enhancing regulation of mental states and allocation of attentional resources.
Jaap van Dieen
Christanie Monreal, Lindsay Luinstra, Lindsay Larkins, and James May
Context: Technological advances have given smartphones the capabilities of sensitive clinical measurement equipment at lesser cost and higher availability. The Clinometer is a smartphone application that can be used to measure the joint range of motion in a clinical setting, but psychometric properties of the tool’s use measuring cervical range of motion (CROM) are not established. Objectives: The purpose of this study was to examine the validity and intrarater reliability of the Clinometer application for the measurement of CROM (ie, flexion, extension, rotation, lateral flexion) and to determine the minimal detectable change and SEM. Design: A blinded, repeated-measures correlational design was employed. Setting: The study was conducted collaboratively between 2 athletic training clinics. Participants: A convenience sample of healthy adults ages 18–30 years were recruited. Participants with any history in the last 3 months of cervical or thoracic pathology, pain, or any musculoskeletal injury were excluded. Main Outcome Measures: Three repetitions of each motion were measured by a primary researcher with a goniometer. The same researcher then conducted 3 blinded measurements with the Clinometer application following the same procedure. A second researcher, blinded to the goniometer measurements, recorded the results. Thirty minutes later, testing was repeated with the application. The Pearson correlation was calculated to determine validity of the application compared with goniometry. Results: The measurements between devices had moderate to excellent concurrent validity, with the coefficients ranging between 0.544 and 0.888, P < .01. Test–retest reliability of the CROM measurement using the application was moderate to excellent, with intraclass correlation coefficients ranging between .774 and .928. Across all movements, the SEM ranged from 1.17° to 2.01°, and the minimal detectable change ranged from 1.18° to 2.02°. Conclusion: The Clinometer application is a valid and reliable instrument for measuring active CROM. Level of evidence: clinical measurement, level 1b.