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Paul Head, Mark Waldron, Nicola Theis and Stephen David Patterson

Context: Neuromuscular electrical stimulation (NMES) combined with blood flow restriction (BFR) has been shown to improve muscular strength and size better than NMES alone. However, previous studies used varied methodologies not recommended by previous NMES or BFR research. Objective: The present study investigated the acute effects of NMES combined with varying degrees of BFR using research-recommended procedures to enhance understanding and the clinical applicability of this combination. Design: Randomized crossover. Setting: Physiology laboratory. Participants: A total of 20 healthy adults (age 27 [4] y; height 177 [8] cm; body mass 77 [13] kg). Interventions: Six sessions separated by at least 7 days. The first 2 visits served as familiarization, with the experimental conditions performed in the final 4 sessions: NMES alone, NMES 40% BFR, NMES 60% BFR, and NMES 80% BFR. Main Outcome Measures: Maximal voluntary isometric contraction, muscle thickness, blood pressure, heart rate, rating of perceived exertion, and pain were all recorded before and after each condition. Results: The NMES 80% BFR caused greater maximal voluntary isometric contraction decline than any other condition (−38.9 [22.3] N·m, P < .01). Vastus medialis and vastus lateralis muscle thickness acutely increased after all experimental conditions (P < .05). Pain and ratings of perceived exertion were higher after NMES 80% BFR compared with all other experimental conditions (P < .05). No cardiovascular effects were observed between conditions. Conclusion: The NMES combined with 80% BFR caused greater acute force decrement than the other conditions. However, greater perceptual ratings of pain and ratings of perceived exertion were observed with NMES 80% BFR. These acute observations must be investigated during chronic interventions to corroborate any relationship to changes in muscle strength and size in clinical populations.

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Yumeng Li, Shuqi Zhang and Christina Odeh

The purposes of the study were (1) to compare postural sway between participants with Parkinson’s disease (PD) and healthy controls and (2) to develop and validate an automated classification of PD postural control patterns using a machine learning approach. A total of 9 participants in the early stage of PD and 12 healthy controls were recruited. Participants were instructed to stand on a force plate and maintain stillness for 2 minutes with eyes open and eyes closed. The center of pressure data were collected at 50 Hz. Linear displacements, standard deviations, total distances, sway areas, and multiscale entropy of center of pressure were calculated and compared using mixed-model analysis of variance. Five supervised machine learning algorithms (ie, logistic regression, K-nearest neighbors, Naïve Bayes, decision trees, and random forest) were used to classify PD postural control patterns. Participants with PD exhibited greater center of pressure sway and variability compared with controls. The K-nearest neighbor method exhibited the best prediction performance with an accuracy rate of up to 0.86. In conclusion, participants with PD exhibited impaired postural stability and their postural sway features could be identified by machine learning algorithms.

Open access

Amanda L. Ager, Dorien Borms, Magali Bernaert, Vicky Brusselle, Mazarine Claessens, Jean-Sébastien Roy and Ann Cools

Context: Proprioception deficits contribute to persistent and recurring physical disability, particularly with shoulder disorders. Proprioceptive training is thus prescribed in clinical practice. It is unclear whether nonsurgical rehabilitation can optimize shoulder proprioception. Objectives: To summarize the available evidence of conservative rehabilitation (ie, nonsurgical) on proprioception among individuals with shoulder disorders. Evidence Acquisition: PubMed, Web of Science, and EBSCO were systematically searched, from inception until November 24, 2019. Selected articles were systematically assessed, and the methodological quality was established using the Dutch Cochrane Risk of Bias Tool and the Newcastle-Ottawa Quality Assessment Scale. The Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines were utilized for this review. The conservative treatments were categorized as follows: (1) conventional therapy, (2) proprioceptive training, (3) elastic kinesiology tape, and (4) other passive therapies. Evidence Synthesis: Twelve articles were included, yielding 58 healthy control shoulders and 362 shoulders affected by impingement syndrome, glenohumeral dislocations, nonspecific shoulder pain, rotator cuff dysfunction, or subluxation poststroke. The level of agreement between the evaluators was excellent (84.9%), and the studies were evaluated to be of fair to excellent quality (risk of bias: 28.5%–100%). This review suggests, with moderate evidence, that proprioceptive training (upper-body wobble board or flexible foil training) can improve proprioception in the midterm. No decisive evidence exists to suggest that conventional therapy is of added value to enhance shoulder proprioception. Conflicting evidence was found for the improvement of proprioception with the application of elastic kinesiology tape, while moderate evidence suggests that passive modalities, such as microcurrent electrical stimulation and bracing, are not effective for proprioceptive rehabilitation of the shoulder. Conclusions: Proprioceptive training demonstrates the strongest evidence for the effective rehabilitation of individuals with a shoulder proprioceptive deficit. Elastic kinesiology tape does not appear to affect the sense of shoulder proprioception. This review suggests a possible specificity of training effect with shoulder proprioception.

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Kyle M. Petit and Tracey Covassin

Context: Cognitive and physical rest are commonly utilized when managing a sport-related concussion (SRC); however, emerging research now suggests that excessive rest may negatively impact recovery. Despite current research recommendations, athletic trainers (ATs) may be behind in implementing this emerging research into clinical practice. Objective: To assess college ATs’ perceptions and implementation of an emerging SRC management approach (cognitive and physical rest and activity). Design: Cross-sectional study. Setting: Survey. Participants: A total of 122 (11.8%) ATs (53.3% female; 10.8 [9.8] y experience; 8.7 [6.9] SRCs managed annually) responded to the survey, which was randomly distributed to 1000 members of the National Athletic Trainers’ Association, as well as 31 additional ATs from varying universities. Main Outcome Measures: A 5-point Likert scale assessed the ATs’ perceptions and clinical practices as they relate to specific athlete behaviors (ie, texting, sleeping). The ATs were asked about their willingness to incorporate physical activity into clinical practice. Results: Playing video games (95.9%) and practicing (93.4%) were the activities most perceived to extend SRC recovery. However, sleeping more than usual (7.4%) and increased time in a dark environment (11.5%) were viewed as less likely to extend recovery. ATs restricted practicing (98.4%) and working out (91.8%) for athletes with SRC, while sleeping more than usual (6.6%) and increased time in a dark environment (13.1%) were less restricted. About 71% of the ATs would implement light physical activity for athletes with a symptom score of 1 to 5, 31% with scores of 6 to 10, and 15% with scores of 11 to 20. About 43%, 74%, and 97% believe that light, moderate, and vigorous physical activity, while symptomatic, will extend recovery, respectively. Conclusions: The ATs were receptive to including light physical activity into their SRC management, although only in certain situations. However, most ATs’ beliefs and clinical practices did not completely align with emerging research recommendations for the management of SRCs.

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Seth T. Strayer, Seyed Reza M. Moghaddam, Beth Gusenoff, Jeffrey Gusenoff and Kurt E. Beschorner

Pressure offloading is critical to diabetic foot ulcer healing and prevention. A novel product has been proposed to achieve this offloading with an insole that can be easily modified for each user. This insole consists of pressurized bubbles that can be selectively perforated and depressurized to redistribute weight to the nonulcer region of the foot. However, the effect of the insole design parameters, for example, bubble height and stiffness, on offloading effectiveness is unknown. To this end, a 3-dimensional finite element model was developed to simulate contact between the rearfoot and insole. The geometry of the calcaneus bone and soft tissue was based on the medical images of an average male patient, and material properties and loading conditions based on the values reported in the literature were used. The model predicts that increasing bubble height and stiffness leads to a more effectively offloaded region. However, the model also predicts that increasing stiffness leads to increasing contact pressures on the surrounding soft tissue. Thus, a combination of insole design parameters was determined, which completely offloads the desired region, while simultaneously reducing the contact pressure on the surrounding soft tissue. This design is expected to aid in diabetic foot ulcer healing and prevention.

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Jason M. Avedesian, Tracey Covassin and Janet S. Dufek

Recent evidence suggests previously concussed athletes are at greater risk for lower-extremity (LE) injuries than are controls. However, little is known regarding the influence of sports-related concussion (SRC) on landing biomechanics that may provide a mechanistic rationale for LE injury risk. The purpose of this investigation was to examine LE drop-landing biomechanics in adolescent athletes with and without a previous SRC history. Participants included 10 adolescent athletes with an SRC history and 11 controls from multiple sports. Three-dimensional kinematic and kinetic data associated with LE injury risk were analyzed across 5 trials for 30- and 60-cm landing heights. Multivariate analyses indicated group differences in landing patterns from the 30- (P = .041) and 60-cm (P = .015) landing heights. Follow-up analyses indicated that concussed adolescent athletes demonstrated significantly less ankle dorsiflexion and knee flexion versus controls when performing drop landings. Our findings suggest that previously concussed adolescent athletes complete drop-landing maneuvers with ankle and knee joint kinematic patterns that suggest greater risk for LE injury. While limitations such as sport variety and explicit LE injury history are present, the results of this study provide a possible biomechanical rationale for the association between SRC and LE injury risk.

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Pedro Ángel Latorre-Román, Juan Francisco Fernández-Povedano, Jesús Salas-Sánchez, Felipe García-Pinillos and Juan Antonio Párraga-Montilla

This study aimed to evaluate spatial and temporal perception in endurance runners as a mechanism of pacing control in comparison with other athletes (soccer players). A group of 38 endurance runners and 32 soccer players participated in this study. Runners displayed lower time differences and lower error than soccer players. Taking the athletic levels of endurance runners into consideration, significant differences (p = .011, Cohen’s d = 1.042) were found in the time differences (higher level group = 33.43 ± 29.43 vs. lower level group = 123.53 ±102.61). Significant correlations were found between time differences and performance in a Cooper test (r = −.546) and with the best time in a half marathon (r = .597). Temporal and spatial perception can be considered as a cognitive skill of endurance runners.

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Erika D. Van Dyke, Aaron Metzger and Sam J. Zizzi

Little research has integrated mindfulness and perfectionism, particularly within sports wherein athletes are judged on performance to a standard of perfection. The current study had two primary aims: (a) to explore profiles of mindfulness and perfectionism among intercollegiate gymnasts through a person-centered approach and (b) to analyze differences in objective performance across the resulting profiles. The analytic sample consisted of 244 NCAA gymnasts who completed self-report measures of mindfulness and perfectionism. Competitive performance records (i.e., national qualifying scores) were then gathered for participating gymnasts. Cluster analyses revealed a three-cluster solution; however, significant performance differences were not observed across the three profiles due to lower than desired power. Small to moderate effect size estimates provided some evidence that perfectionism may be adaptive to gymnastics performance. Elite-level athletes were represented across three distinct profiles, suggesting that more than one profile of characteristics may be adaptive for reaching high levels of performance.

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Anderson Nascimento Guimarães, Herbert Ugrinowitsch, Juliana Bayeux Dascal and Victor Hugo Alves Okazaki

To test Bernstein’s degrees of freedom (DF) hypothesis, the authors analyzed the effect of practice on the DF control and interjoint coordination of a Taekwondo kick. Thirteen inexperienced and 11 expert Taekwondo practitioners were evaluated. Contrary to Bernstein’s hypothesis, the inexperienced group froze the DF at the end of learning, reducing the joint range of motion of the knee. Moderate and strong cross-correlations between joints did not change, demonstrating that the interjoint coordination was maintained. The inexperienced group’s movement pattern was similar to that of the group of experts, from the beginning of the learning process. Thus, even after years of practice, experts continue to explore the strategy of freezing DF. The DF freeing/freezing sequence strategy was explored during the learning process, suggesting that DF-freezing/freeing strategies are task dependent.

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Michelle A. Sandrey

Focused Clinical Question: Does a passive stretching protocol, whether immediate or long-term, improve range of motion and decrease posterior shoulder tightness in overhead athletes? Clinical Bottom Line: There is moderate level 2 evidence to support the incorporation of passive stretching for overhead athletes to increase range of motion or decrease posterior shoulder tightness.