Obese (OB) youth demonstrate altered knee mechanics and worse lower-extremity performance compared with healthy weight (HW) youth. Our objectives were to compare sagittal plane knee landing mechanics between OB and HW youth and to examine the associations of knee and hip extension peak torque with landing mechanics in OB youth. Twenty-four OB and 24 age- and sex-matched HW youth participated. Peak torque was measured and normalized to leg lean mass. Peak knee flexion angle and peak internal knee extension moment were measured during a single-leg hop landing. Paired t tests, Pearson correlation coefficients, and Bonferroni corrections were used. OB youth demonstrated worse performance and lower knee extension (OB: 12.76 [1.38], HW: 14.03 [2.08], P = .03) and hip extension (OB: 8.59 [3.13], HW: 11.10 [2.89], P = .005) peak torque. Furthermore, OB youth demonstrated lower peak knee flexion angles (OB: 48.89 [45.41 to 52.37], HW: 56.07 [52.59 to 59.55], P = .02) and knee extension moments (OB: −1.73 [−1.89 to −1.57], HW: −2.21 [−2.37 to −2.05], P = .0001) during landing compared with HW youth. Peak torque measures were not correlated with peak knee flexion angle nor internal knee extension moment during landing in either group (P > .01). OB youth demonstrated altered landing mechanics compared with HW youth. However, no associations among peak torque measurements and knee landing mechanics were present.
Matthew S. Briggs, Claire Spech, Rachel King, Mike McNally, Matthew Paponetti, Sharon Bout-Tabaku and Laura Schmitt
Jereme B. Outerleys, Michael J. Dunbar, Glen Richardson, Cheryl L. Hubley-Kozey and Janie L. Astephen Wilson
Total knee arthroplasty (TKA) surgery improves knee joint kinematics and kinetics during gait for most patients, but a lack of evidence exists for the level and incidence of improvement that is achieved. The objective of this study was to quantify patient-specific improvements in knee biomechanics relative to osteoarthritis (OA) severity levels. Seventy-two patients underwent 3-dimensional (3D) gait analysis before and 1 year after TKA surgery, as well as 72 asymptomatic adults and 72 with moderate knee OA. A combination of principal component analysis and discriminant analyses were used to categorize knee joint biomechanics for patients before and after surgery relative to asymptomatic, moderate, and severe OA. Post-TKA, 63% were categorized with knee biomechanics consistent with moderate OA, 29% with severe OA, and 8% asymptomatic. The magnitude and pattern of the knee adduction moment and angle (frontal plane features) were the most significant contributors in discriminating between pre-TKA and post-TKA knee biomechanics. Standard of care TKA improves knee biomechanics during gait to levels most consistent with moderate knee OA and predominately targets frontal plane features. These results provide evidence for the level of improvement in knee biomechanics that can be expected following surgery and highlight the biomechanics most targeted by surgery.
Steven M. Davi, Colleen K. Woxholdt, Justin L. Rush, Adam S. Lepley and Lindsey K. Lepley
Context: Traditionally, quadriceps activation failure after anterior cruciate ligament reconstruction (ACLR) is estimated using discrete isometric torque values, providing only a snapshot of neuromuscular function. Sample entropy (SampEn) is a mathematical technique that can measure neurologic complexity during the entirety of contraction, elucidating qualities of neuromuscular control not previously captured. Objective: To apply SampEn analyses to quadriceps electromyographic activity in order to more comprehensively characterize neuromuscular deficits after ACLR. Design: Cross-sectional. Setting: Laboratory. Participants: ACLR: n = 18; controls: n = 24. Interventions: All participants underwent synchronized unilateral quadriceps isometric strength, activation, and electromyography testing during a superimposed electrical stimulus. Main Outcome Measures: Group differences in strength, activation, and SampEn were evaluated with t tests. Associations between SampEn and quadriceps function were evaluated with Pearson product–moment correlations and hierarchical linear regressions. Results: Vastus medialis SampEn was significantly reduced after ACLR compared with controls (P = .032). Vastus medialis and vastus lateralis SampEn predicted significant variance in activation after ACLR (r2 = .444; P = .003). Conclusions: Loss of neurologic complexity correlates with worse activation after ACLR, particularly in the vastus medialis. Electromyographic SampEn is capable of detecting underlying patterns of variability that are associated with the loss of complexity between key neurophysiologic events after ACLR.
Joseph M. Day, Ann M. Lucado, R. Barry Dale, Harold Merriman, Craig D. Marker and Tim L. Uhl
Context: There is a lack of consensus on the best management approach for lateral elbow tendinopathy (LET). Recently, scapular stabilizer strength impairments have been found in individuals with LET. Objective: The purpose of this study was to compare the effectiveness of local therapy (LT) treatment to LT treatment plus a scapular muscle-strengthening (LT + SMS) program in patients diagnosed with LET. Design: Prospective randomized clinical trial. Setting: Multisite outpatient physical therapy. Patients: Thirty-two individuals with LET who met the criteria were randomized to LT or LT + SMS. Interventions: Both groups received education, a nonarticulating forearm orthosis, therapeutic exercise, manual therapy, and thermal modalities as needed. Additionally, the LT + SMS group received SMS exercises. Main Outcome Measure: The primary outcome measure was the patient-rated tennis elbow evaluation; secondary outcomes included global rating of change (GROC), grip strength, and periscapular muscle strength. Outcomes were reassessed at discharge, 6, and 12 months from discharge. Linear mixed-effect models were used to analyze the differences between groups over time for each outcome measure. Results: The average duration of symptoms was 10.2 (16.1) months, and the average total number of visits was 8.0 (2.2) for both groups. There were no significant differences in gender, age, average visits, weight, or height between groups at baseline (P > .05). No statistical between-group differences were found for any of the outcome measures. There were significant within-group improvements in all outcome measures from baseline to all follow-up points (P < .05). Conclusion: The results of this pilot study suggest that both treatment approaches were equally effective in reducing pain, improving function, and increasing grip strength at discharge as well as the 6- and 12-month follow-ups. Our multimodal treatment programs were effective at reducing pain and improving function up to 1 year after treatment in a general population of individuals with LET.
Samantha M. Ross, Ellen Smit, Joonkoo Yun, Kathleen R. Bogart, Bridget E. Hatfield and Samuel W. Logan
A secondary data analysis of 33,093 children and adolescents age 6–17 years (12% with disabilities) from a 2016–2017 National Survey of Children’s Health nonrepresentative sample aimed to identify (a) unique clusters of sociodemographic characteristics and (b) the relative importance of disability status in predicting participation in daily physical activity (PA) and sports. Exploratory classification tree analyses identified hierarchical predictors of daily PA and sport participation separately. Disability status was not a primary predictor of daily PA. Instead, it emerged in the fifth level after age, sex, body mass index, and income, highlighting the dynamic intersection of disability with sociodemographic factors influencing PA levels. In comparison, disability status was a second-level predictor for sport participation, suggesting that unique factors influencing PA level are likely experienced by disabled children and adolescents. The authors employ an intersectionality lens to critically discuss implications for research in adapted PA.
Cagla Ozkul, Arzu Guclu-Gunduz, Kader Eldemir, Yasemin Apaydin, Cagri Gulsen, Gokhan Yazici, Fatih Soke and Ceyla Irkec
This study aimed to investigate the dual-task cost of both motor and cognitive performances in patients with multiple sclerosis (PwMS) and in healthy controls and to determine their relationships with clinical features in PwMS. The participants performed motor tasks (postural stability, walking, and manual dexterity) and cognitive tasks (mental tracking and verbal fluency) under single- and dual-task conditions. The results showed that postural stability under dual-task conditions did not change, whereas walking and manual dexterity deteriorated, regardless of the concurrent cognitive task, in PwMS (median Expanded Disability Status Scale score: 1) and the healthy controls. Verbal fluency decreased during postural stability, whereas it increased during walking, and it was maintained during manual dexterity in both groups. Mental tracking did not change during walking; it declined during manual dexterity in both groups. Mental tracking during postural stability deteriorated in PwMS, while it did not change in the healthy controls. In general, dual-task costs were associated with baseline performances of tasks rather than clinical features. Therefore, baseline performances of both tasks should be increased for improving dual-task performance in PwMS.
Julie Freedman, Sally Hage and Paula A. Quatromoni
Male athletes are underrepresented in eating disorders research. This phenomenological study investigated the experiences of male athletes who self-identified as having an eating disorder, disordered eating, or compulsive exercise behaviors. Eight male collegiate athletes were interviewed, and qualitative analysis identified factors associated with the onset and maintenance of disordered behaviors. Among the novel findings was the salient influence of social media as a driver of body dissatisfaction and disordered behaviors. The participants described a perceived sense of control and feeling of pride associated with the use of behaviors, cultural norms in a male sport environment that sustained these behaviors, and a shared belief that, until they experienced a loss of control over their use of behaviors, they would not likely ask for help or seek treatment. These findings have implications for additional research, as well as individual and systems-level strategies for the prevention, screening, and treatment of eating and exercise disorders in male sport.
Matthew D. Bird, Eadie E. Simons and Patricia C. Jackman
Mental toughness has been associated with factors related to psychological well-being, but little is known about its relationship with stigma toward mental health and mental health help-seeking. This study investigated the relationship between mental toughness, sport-related well-being, and personal stigma toward mental health in a sample of 154 National Collegiate Athletic Association Division I student-athletes. The moderating effect of mental toughness on the relationship between public stigma and self-stigma toward mental health help-seeking was also explored. Mental toughness was significantly and positively associated with sport-related well-being, but not significantly related to personal stigma toward mental health. Moderation analysis indicated that mental toughness was not a significant moderator of the relationship between public stigma and self-stigma, but higher levels of mental toughness were significantly associated with lower levels of stigma toward mental health help-seeking. Building mental toughness may be a way to increase well-being and to reduce stigma toward help-seeking in student-athletes.
Richard Tahtinen, Hafrun Kristjansdottir, Daniel T. Olason and Robert Morris
The aim of the study was to explore the prevalence of specific symptoms of depression in athletes and to test differences in the likelihood of athletes exhibiting these symptoms across age, sex, type of team sport, and level of competition. A sample of Icelandic male and female team sport athletes (N = 894, 18–42 years) was included in the study. Of the athletes exhibiting clinically significant depressive symptoms on the Patient Health Questionnaire-9, 37.5% did not exhibit core symptoms of depression. Compared with males, females were significantly more likely to exhibit depressed mood, feelings of worthlessness/guilt, and problems with sleep, fatigue, appetite, and concentration. Within males, differences were mostly related to neurovegetative aspects of depression (sleep and appetite), whereas in females, differences were related to cognitive/emotional aspects (e.g., depressed mood, guilt/worthlessness). The findings underline the importance of exploring specific symptoms of depression to provide a richer understanding of depressive symptomology in athletes.
Davoud Fazeli, HamidReza Taheri and Alireza Saberi Kakhki
The simulation theory argues that physical execution, action observation, and imagery share similar underlying mechanisms. Accordingly, applying a high-level psychological variable (variability of practice) should have a similar effect on all three modes. To test this theory, a total of 90 right-handed students participated in this study and were randomly divided into variable versus constant groups in three practice conditions, including physical, observational, and imagery. After a pretest (10 random trials of the putting task), the participants completed 50 practice trials. The groups performed/observed/imagined the task in the variable (different distances to different goals) or constant (fixed distance and goal) practice conditions. Also, there was an extra variable group in the physical and observational conditions, deprived of watching the feedback from the action. The participants completed a retention test 24 hr after the training. The effect of practice variability was observed in physical and observational conditions, but was not seen in the imagery condition. The no-feedback groups did not perform significantly differently from the imagery groups. The reason could be the lack of actual visual feedback during imagery.