Context: This study aimed to examine the differences in electromyographic (EMG) activity of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles, break-point angle (BPA), and the angle at peak BFlh EMG activity between bilateral and unilateral Nordic hamstring exercise (NHE) on a sloped platform. Design: This study was designed as a case-control study. Methods: Fourteen men participated in the study. The participants initially performed maximum voluntary isometric contraction (MVIC) on the prone leg curl to normalize the peak hamstring EMG amplitude as the %MVIC. Then, participants were randomized to perform the following 3 variations of NHE: bilateral (N40) or unilateral (N40U) NHE with a platform angle of 40°, and unilateral NHE with a platform angle of 50° (N50U). The EMG activities of the BFlh and ST and the knee flexion angle during the NHE variations were recorded to calculate the EMG activity of the BFlh and ST in terms of the %MVIC, the angle at peak BFlh EMG, and BPA. Results: The BFlh %MVIC was significantly higher in N40U (P < .05) and N50U (P < .05) than in N40. A significant difference in BFlh %MVIC and ST %MVIC was observed between N40U (P < .05) and N50U (P < .05). The mean values of BPA and the angle at peak BFlh EMG were <30° for all NHE variations. Conclusions: In the late swing phase of high-speed running, BFlh showed higher EMG activity; thus, unilateral NHE may be a specific hamstring exercise for hamstring injury prevention.
Toshiaki Soga, Taspol Keerasomboon, Kei Akiyama, and Norikazu Hirose
Eugene Tee, Jack Melbourne, Larissa Sattler, and Wayne Hing
Context: Acute lateral ankle sprain (LAS) is a common injury in athletes and is often associated with decreased athletic performance and, if treated poorly, can result in chronic ankle issues, such as instability. Physical performance demands, such as cutting, hopping, and landing, involved with certain sport participation suggests that the rehabilitation needs of an athlete after LAS may differ from those of the general population. Objective: To review the literature to determine the most effective rehabilitation interventions reported for athletes returning to sport after acute LAS. Evidence Acquisition: Data Sources: Databases PubMed, Embase, CINAHL, SPORTDiscus, and PEDro were searched to July 2020. Study Selection: A scoping review protocol was developed and followed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews guidelines and registered (https://osf.io/bgek3/). Study selection included published articles on rehabilitation for ankle sprain in an athletic population. Data Extraction: Parameters included athlete and sport type, age, sex, intervention investigated, outcome measures, measurement tool, and follow-up period. Data Synthesis: A qualitative synthesis for all articles was undertaken, and a quantitative subanalysis of randomized controlled trials and critical methodological appraisal was also conducted. Evidence Synthesis: A total of 37 articles were included in this review consisting of 5 systematic and 20 narrative reviews, 7 randomized controlled trials, a single-case series, case report, position statement, critically appraised topic, and descriptive study. Randomized controlled trial interventions included early dynamic training, electrotherapy, and hydrotherapy. Conclusions: Early dynamic training after acute LAS in athletes results in a shorter time to return to sport, increased functional performance, and decreased self-reported reinjury. The results of this scoping review support an early functional and dynamic rehabilitation approach when compared to passive interventions for athletes returning to sport after LAS. Despite existing research on rehabilitation of LAS in the general population, a lack of evidence exists related to athletes seeking to return to sport.
Stephanie Wise and Jordan Bettleyon
Clinical Scenario: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy of the upper-extremity. Due to the involvement of the median nerve, long-term compression of this nerve can lead to hand dysfunction and disability that can impact work and daily life. As such, early treatment is warranted to prevent any long-term damage to the median nerve. Conservative management is utilized in those with mild to moderate CTS. Neural mobilizations can aid in the reduction of neural edema, neural mobility, and neural adhesion while improving nerve conduction. Clinical Question: Is neurodynamics effective in reducing pain and reported symptoms in those with CTS? Summary of Key Findings: Four studies were included, with 2 studies utilizing passive neural mobilizations, one study using active techniques, and one study using active neural mobilizations with splinting. All studies showed large effect size for pain, symptom severity, and physical function. Clinical Bottom Line: Neurodynamics is an effective treatment for CTS. Splinting is only effective when combined with neurodynamics. Strength of Recommendation: Level B evidence to support the use of neurodynamics for the treatment of CTS.
Masahiro Kuniki, Yoshitaka Iwamoto, Daiki Yamagiwa, and Nobuhiro Kito
Context: Core stability is important for preventing injury and improving performance. Although various tests for evaluating core stability have been reported to date, information on their relationship and the effect of gender differences is limited. This study aimed to (1) identify correlations among the 3 core stability tests and to examine the validity of each test and (2) identify gender differences in the test relationship and determine whether gender influenced test selection. Design: Cross-sectional study. Methods: Fifty-one healthy volunteers (27 men and 24 women) participated in the study. The participants underwent the following 3 tests: Sahrmann Core Stability Test (SCST), the lumbar spine motor control tests battery (MCBT), and Y Balance Test (YBT). Each parameter was analyzed according to all parameters and gender using the Spearman rank correlation coefficient. Results: Overall, there was a strong positive correlation between SCST and MCBT and moderate positive correlations between SCST and YBT and between MCBT and YBT. Conversely, gender-specific analyses revealed no significant correlations between YBT and SCST and between YBT and MCBT in women, although significantly strong correlations were found among all tests in men. Conclusion: Although these 3 tests evaluated interrelated functions and may be valid as core stability tests, the results should be carefully interpreted when performing YBT in women.
Tyler M. Saumur, Jacqueline Nestico, George Mochizuki, Stephen D. Perry, Avril Mansfield, and Sunita Mathur
This study aimed to determine the relationship between lower limb muscle strength and explosive force with force plate–derived timing measures of reactive stepping. Nineteen young, healthy adults responded to 6 perturbations using an anterior lean-and-release system. Foot-off, swing, and restabilization times were estimated from force plates. Peak isokinetic torque, isometric torque, and explosive force of the knee extensors/flexors and plantar/dorsiflexors were measured using isokinetic dynamometry. Correlations were run based on a priori hypotheses and corrected for the number of comparisons (Bonferroni) for each variable. Knee extensor explosive force was negatively correlated with swing time (r = −.582, P = .009). Knee flexor peak isometric torque also showed a negative association with restabilization time (r = −.459, P = .048); however, this was not statistically significant after correcting for multiple comparisons. There was no significant relationship between foot-off time and knee or plantar flexor explosive force (P > .025). These findings suggest that there may be utility to identifying specific aspects of reactive step timing when studying the relationship between muscle strength and reactive balance control. Exercise training aimed at improving falls risk should consider targeting specific aspects of muscle strength depending on specific deficits in reactive stepping.
Kayla M. Fewster, Jackie D. Zehr, Chad E. Gooyers, Robert J. Parkinson, and Jack P. Callaghan
Background: Recent work has demonstrated that low back pain is a common complaint following low-speed collisions. Despite frequent pain reporting, no studies involving human volunteers have been completed to examine the exposures in the lumbar spine during low-speed rear impact collisions. Methods: Twenty-four participants were recruited and a custom-built crash sled simulated rear impact collisions, with a change in velocity of 8 km/h. Randomized collisions were completed with and without lumbar support. Inverse dynamics analyses were conducted, and outputs were used to generate estimates of peak L4/L5 joint compression and shear. Results: Average (SD) peak L4/L5 compression and shear reaction forces were not significantly different without lumbar support (compression = 498.22 N [178.0 N]; shear = 302.2 N [98.5 N]) compared to with lumbar support (compression = 484.5 N [151.1 N]; shear = 291.3 N [176.8 N]). Lumbar flexion angle at the time of peak shear was 36° (12°) without and 33° (11°) with lumbar support. Conclusion: Overall, the estimated reaction forces were 14% and 30% of existing National Institute of Occupational Safety and Health occupational exposure limits for compression and shear during repeated lifting, respectively. Findings also demonstrate that, during a laboratory collision simulation, lumbar support does not significantly influence the total estimated L4/L5 joint reaction force.
Eduardo Stieler, Varley Teoldo da Costa, Aline Ângela Silva Cruz, João Paulo Pereira Rosa, Ingrid LudImilla Bastos Lôbo, Julia Romão, Andrea Maculano Esteves, Marco Tulio de Mello, and Andressa Silva
Context: Hormonal assessment in the sport context is important to monitor the physiological adaptations of athletes. However, Paralympic athletes, especially with cervical spinal cord injury (CSCI), may have different hormonal responses than nondisabled athletes. Therefore, the aim of this study was to evaluate the blood concentrations of total testosterone (TT) and cortisol (C) during acute (one training session) and chronic (1 and 2 month) training of athletes with CSCI in wheelchair rugby (WCR). Design: Longitudinal and observational study. Methods: Eight high-performance athletes with CSCI (31 [3.9] y; 75.6 [15.8] kg; 22.9 [4.2] kg/m2 body mass index; 6.2  y of experience in sport) were evaluated at 3 different intervals (evaluations 1, 2, and 3 [E1, E2, and E3]) over 2 months of training. TT and C blood were evaluated before (pre) and after (post) the training sessions at each training moment, as well as the training load through the ratings of perceived exertion. Results: Athletes with CSCI had low TT concentrations. In acute training sessions, at E3, C decreases after the training session, unlike the TT/C ratio, which increased after the session. Regarding hormonal changes during chronic training at the end of the training period, unlike C, which increased. The training load (arbitrary units) decreased in E3 when compared with the other evaluation moments. Conclusion: It was concluded that in chronic training, TT concentrations decreased, while C increased at the end of the 2 months of training. These results may indicate that training volume was high throughout training and that a reduction in training volume could benefit athletes. On the other hand, in the acute training session with reduced training load, a decrease in C was observed after the training session. This indicates that athletes may be well recovered in this training session. Therefore, we suggest acute and long-term hormonal assessment for athletes with CSCI as a strategy to monitor anabolic/catabolic hormonal status during WCR training.
Nicole Jones, Kelsey M. Rynkiewicz, and Stephanie M. Singe
Context: The COVID-19 pandemic has potential ramifications on work–life balance for those working in health care. Purpose: The purpose of this study was to better understand COVID-19 on work–life balance and quality of life among collegiate athletic trainers. Method: Data for this study were generated from 636 eligible respondents (33 ± 9 years) representing Division I, II, and III (n = 360, n = 104, and n = 172, respectively) settings. Results: Four main themes emerged from consensual qualitative data analysis: mental health impact, social responsibility, work–life boundaries, and 24/7 work demands. Conclusion: The results suggest that collegiate athletic trainers are struggling to find work–life balance and must find ways to implement self-care practices.
Tal Krasovsky, Rawda Madi, Eyal Fruchter, Elias Jahjah, and Roee Holtzer
Texting while walking is an increasingly common, potentially dangerous task but its functional brain correlates have yet to be reported. Therefore, we evaluated prefrontal cortex (PFC) activation patterns during single- and dual-task texting and walking in healthy adults. Thirteen participants (29–49 years) walked under single- and dual-task conditions involving mobile phone texting or a serial-7s subtraction task, while measuring PFC activation (functional near-infrared spectroscopy) and behavioral task performance (inertial sensors, mobile application). Head lowering during texting increased PFC activation. Texting further increased PFC activation, and decreased gait performance similarly to serial-7 subtraction. Our results support the key role of executive control in texting while walking.