The purpose of this study was to investigate effects of preferred step width and increased step width modification on knee biomechanics of obese and healthy-weight participants during incline and decline walking. Seven healthy-weight participants and 6 participants who are obese (body mass index ≥ 30) performed 5 walking trials on level ground and a 10° inclined and declined instrumented ramp system at both preferred and wide step-widths. A 2 × 2 (step-width × group) mixed-model analysis of variance was used to examine selected variables. There were significant increases in step-width between the preferred and wide step-width conditions for all 3 walking conditions (all P < .001). An interaction was found for peak knee extension moment (P = .048) and internal knee abduction moment (KAM) (P = .025) in uphill walking. During downhill walking, there were no interaction effects. As step-width increased, KAM was reduced (P = .007). In level walking, there were no interaction effects for peak medial ground reaction force and KAM (P = .007). There was a step-width main effect for KAM (P = .007). As step-width increased, peak medial ground reaction force and peak knee extension moment increased, while KAM decreased for both healthy weight and individuals who are obese. The results suggest that increasing step-width may be a useful strategy for reducing KAM in healthy and young populations.
Daniel W. Sample, Tanner A. Thorsen, Joshua T. Weinhandl, Kelley A. Strohacker and Songning Zhang
Kevin G. Aubol, Jillian L. Hawkins and Clare E. Milner
Measurements of tibial acceleration during running must be reliable to ensure valid results and reduce errors. The purpose of this study was to determine the reliability and minimal detectable difference (MDD) of peak axial and peak resultant tibial acceleration during overground and treadmill running. The authors also compared reliability and MDDs when peak tibial accelerations were determined by averaging 5 or 10 trials. Tibial acceleration was measured during overground and treadmill running of 19 participants using a lightweight accelerometer mounted to the tibia. Peak axial and peak resultant tibial accelerations were determined for each trial. Intraclass correlation coefficients determined within-session reliability, and MDDs were also calculated. Within-session reliability was excellent for all conditions (intraclass correlation coefficients = .95–.99). The MDDs ranged from 0.6 to 1.4 g for peak axial acceleration and from 1.6 to 2.0 g for peak resultant acceleration and were lowest for peak axial tibial acceleration during overground running. Averaging 10 trials did not improve reliability compared to averaging 5 trials but did result in small reductions in MDDs. For peak axial tibial acceleration only, lower MDDs indicate that overground running may be the better option for detecting small differences.
Matthew C. Hoch, Johanna M. Hoch, Cameron J. Powden, Emily H. Gabriel and Lauren A. Welsch
Background: The anterior reach distance and symmetry of the Y-Balance Test (YBT) has been associated with increased injury risk in collegiate athletes. Examining the influence of dorsiflexion range of motion (DROM) and single-limb balance (SLB) on YBT performance may identify underlying factors associated with injury risk. Objective: The purpose of this study is to determine if YBT anterior reach is related to DROM or SLB in collegiate varsity and club sport athletes. Methods: A convenience sample of 124 university varsity and club sport athletes (females: 99, age: 20.0 ± 1.6 years, height: 168.9 ± 12.5 kg, body mass: 68.8 ± 14.0 kg) completed the anterior direction of the YBT, weight-bearing DROM, and SLB components (firm and foam surface) of the Balance Error Scoring System on both limbs at one testing session. Relative symmetry was calculated by subtracting values of the left limb from the right limb. Results: For the left and right limb, normalized anterior reach distance was moderately correlated to DROM (R = .55, p < .001). Anterior reach distance and symmetry was weakly correlated to SLB and SLB symmetry (R = −.16 to −.03). Conclusion: There was a positive relationship between YBT anterior reach and weight-bearing DROM which was also observed in the between-limb symmetry. However, weak relationships were exhibited between YBT anterior reach and SLB. These findings may be useful for future injury prevention initiatives in athletic settings.
Nadège Tebbache and Alain Hamaoui
The sit-to-stand transfer can be separated into a postural phase (trunk flexion) and a focal phase (whole-body extension). The aim of this study was to analyze the as yet little known whole-body muscular activity characterizing each phase of this task and its variations with backrest inclination and execution speed. Fifteen muscles of the trunk and lower limbs of 10 participants were investigated using surface EMG. Results showed that backrest-induced modifications were mostly confined to the postural phase: reclining the backrest increased its duration and the activity level of the sternocleidomastoideus, the rectus and obliquus externus abdominis, and the semitendinosus. Speed-induced variations were also predominant during the postural phase, which was shortened with an increased activity of most muscles at maximal speed.
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  y; height 177  cm; body mass 77  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.
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.
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.
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.