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Pedro L. Valenzuela, Almudena Montalvo-Perez, Lidia B. Alejo, Mario Castellanos, Jaime Gil-Cabrera, Eduardo Talavera, Alejandro Lucia, and David Barranco-Gil

Purpose : Some power meters are available in both bilateral and unilateral versions. However, despite the popularity of the latter, their validity remains unknown. We aimed to analyze the validity of a unilateral pedal power meter for estimating actual (“bilateral”) power output (PO). Methods: Thirty-three male cyclists were assessed at different POs (steady cycling at 100–500 W, as well as all-out sprints), pedaling cadences (70, 85, and 100 repetitions·min−1), and cycling positions (seated and standing). The PO estimated by a left-only power meter (Favero Assioma Uno) was compared with the actual PO computed by a bilateral power meter (Favero Assioma Duo), and the level of bilateral asymmetry (most- vs least-powerful leg) with the latter system was also computed. Results: Nonsignificant differences, high intraclass correlation coefficients (≥.90), and low coefficients of variation (consistently ≤5% except for low PO levels, ie, 5%–7% at 100 W) were found between Favero Assioma Uno and Favero Assioma Duo. However, although a strong intraclass correlation coefficient (.995) was found between both legs, asymmetry values of 4% to 6% were found for all conditions except when pedaling at the lowest PO (100 W), in which asymmetry increased up to 10% to 13%. Conclusions: Although cyclists tend to present some level of bilateral asymmetry during cycling (particularly at low PO), Favero Assioma Uno provides overall valid estimates of actual PO and is, therefore, an economical alternative to bilateral power meters. Caution is needed, however, when interpreting data at the individual level in cyclists with high levels of asymmetry.

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Felipe Guimarães Teixeira, Paulo Tadeu Cardozo Ribeiro Rosa, Roger Gomes Tavares Mello, and Jurandir Nadal

Purpose: The study aimed to identify the variables that differentiate judo athletes at national and regional levels. Multivariable analysis was applied to biomechanical, anthropometric, and Special Judo Fitness Test (SJFT) data. Method: Forty-two male judo athletes from 2 competitive groups (14 national and 28 state levels) performed the following measurements and tests: (1) skinfold thickness, (2) circumference, (3) bone width, (4) longitudinal length, (5) stabilometric tests, (6) dynamometric tests, and (7) SJFT. The variables with significant differences in the Wilcoxon rank-sum test were used in stepwise logistic regression to select those that better separate the groups. The authors considered models with a maximum of 3 variables to avoid overfitting. They used 7-fold cross validation to calculate optimism-corrected measures of model performance. Results: The 3 variables that best differentiated the groups were the epicondylar humerus width, the total number of throws on the SJFT, and the stabilometric mean velocity of the center of pressure in the mediolateral direction. The area under the receiver-operating-characteristic curve for the model (based on 7-fold cross validation) was 0.95. Conclusion: This study suggests that a reduced set of anthropometric, biomechanical, and SJFT variables can differentiate judo athlete’s levels.

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Toshiaki Soga, Taspol Keerasomboon, Kei Akiyama, and Norikazu Hirose

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.

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Daniel Viggiani and Jack P. Callaghan

Viscoelastic creep generated in the lumbar spine following sustained spine flexion may affect the relationship between tissue damage and perceived pain. Two processes supporting this altered relationship include altered neural feedback and inflammatory processes. Our purpose was to determine how low back mechanical pain sensitivity changes following seated lumbar spine flexion using pressure algometry in a repeated-measures, cross-sectional laboratory design. Thirty-eight participants underwent a 10-minute sustained seated maximal flexion exposure with a 40-minute standing recovery period. Pressure algometry assessed pressure pain thresholds and the perceived intensity and unpleasantness of fixed pressures. Accelerometers measured spine flexion angles, and electromyography measured muscular activity during flexion. The flexion exposure produced 4.4° (2.7°) of creep that persisted throughout the entire recovery period. The perception of low back stimulus unpleasantness was elevated immediately following the exposure, 20 minutes before a delayed increase in lumbar erector spinae muscle activity. Women reported the fixed pressures to be more intense than men. Sustained flexion had immediate consequences to the quality of mechanical stimulus perceived but did not alter pressure pain thresholds. Neural feedback and inflammation seemed unlikely mechanisms for this given the time and direction of pain sensitivity changes, leaving a postulated cortical influence.

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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 ( 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.

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Kerstin Bach, Atle Kongsvold, Hilde Bårdstu, Ellen Marie Bardal, Håkon S. Kjærnli, Sverre Herland, Aleksej Logacjov, and Paul Jarle Mork

Introduction: Accelerometer-based measurements of physical activity types are commonly used to replace self-reports. To advance the field, it is desirable that such measurements allow accurate detection of key daily physical activity types. This study aimed to evaluate the performance of a machine learning classifier for detecting sitting, standing, lying, walking, running, and cycling based on a dual versus single accelerometer setups during free-living. Methods: Twenty-two adults (mean age [SD, range] 38.7 [14.4, 25–68] years) were wearing two Axivity AX3 accelerometers positioned on the low back and thigh along with a GoPro camera positioned on the chest to record lower body movements during free-living. The labeled videos were used as ground truth for training an eXtreme Gradient Boosting classifier using window lengths of 1, 3, and 5 s. Performance of the classifier was evaluated using leave-one-out cross-validation. Results: Total recording time was ∼38 hr. Based on 5-s windowing, the overall accuracy was 96% for the dual accelerometer setup and 93% and 84% for the single thigh and back accelerometer setups, respectively. The decreased accuracy for the single accelerometer setup was due to a poor precision in detecting lying based on the thigh accelerometer recording (77%) and standing based on the back accelerometer recording (64%). Conclusion: Key daily physical activity types can be accurately detected during free-living based on dual accelerometer recording, using an eXtreme Gradient Boosting classifier. The overall accuracy decreases marginally when predictions are based on single thigh accelerometer recording, but detection of lying is poor.

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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.

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Logan T. Markwell, Andrew J. Strick, and Jared M. Porter

Sports, along with nearly all facets of life, have been impacted by the COVID-19 pandemic. The National Basketball Association quickly adopted a unique method to finish the 2019–2020 regular season and playoffs. The entire league quarantined for months in what was known as the “NBA bubble” where games were played in spectator-less arenas. During this time, increases in shooting accuracy were reported, suggesting that free throws and field goals were made at record-breaking levels. This study examined differences in free throw shooting accuracy with and without spectators. Archival data were retrieved and analyzed to evaluate the potential differences. Free throw shooting accuracy with and without spectators were examined in multiple analyses. Our examination revealed free throw percentages were significantly greater in spectator-less arenas compared with the 2018 and 2019 seasons with spectators. Changes of the environmental characteristics, due to spectator-less arenas, were likely contributors to the improved free throw phenomenon reported in this study.

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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.

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Alexandra Stribing, Adam Pennell, Emily N. Gilbert, Lauren J. Lieberman, and Ali Brian

Individuals with visual impairments (VI) trend toward lower motor competence when compared with peers without VI. Various forms of perception often affects motor competence. Thus, it is important to explore factors that influence forms of perception and their differential effects on motor competence for those with VI. Therefore, the purposes of this study were to explore and describe the differential effects of age, gender, and degree of vision on self-perceptions, parents’ perceptions, metaperceptions, and locomotor skills, and to examine potential associations among all variables with actual locomotor competence for adolescents with VI. Adolescents with VI completed two questionnaires and the Test of Gross Motor Development-Third Edition. Parents completed a parent perception questionnaire. Mann–Whitney U and Kruskal–Wallis H analyses showed no differential effects for gender or age on any dependent measures. Degree of vision affected locomotor skills, but not any other factor. Spearman rho correlations showed significant associations among locomotor and self-perceptions, degree of vision and locomotor, and metaperceptions with parents’ perceptions. Adolescents reported relatively high self-perceptions and metaperceptions; however, their actual locomotor competence and parents’ perceptions were relatively low. Findings may help situate future intervention strategies targeting parents supporting their children’s locomotor skills through self-perceptions.