Background:
Previous research has demonstrated that muscle synergy structure can adapt owing to training and injury; however, muscle synergies have not been evaluated in baseball players.
Hypothesis:
...The throwing arm would have a similar muscle synergy structure but different levels of individual muscle activity within each synergy, relative to the nonthrowing arm.
Study Design:
Cross-sectional study in a controlled laboratory setting.
Methods:
Fourteen healthy competitive baseball players were included. Participants were tested bilaterally during a center-out planar reaching task using the KINARM robot, where kinematic data and surface electromyography data from 14 glenohumeral and scapular muscles were synchronized. Principal component analysis was used to extract muscle synergies, the variance accounted for (VAF) of each synergy, and individual muscle coefficients. The dominant (DOM) arm was compared with the nondominant (NDOM) arm using paired t tests for all dependent variables.
Results:
The same number of muscle synergies were extracted on the DOM and NDOM arms, along with no differences in VAF. In the first synergy, the infraspinatus (DOM 0.798 vs NDOM 0.587, P = 0.038) and lower trapezius (DOM 0.872 vs NDOM 0.480, P = 0.005) muscle coefficients significantly increased on the DOM arm. The second synergy had a significantly increased anterior deltoid (DOM 0.764 vs NDOM 0.374, P = 0.003) and a significantly decreased posterior deltoid (DOM −0.069 vs NDOM 0.197, P = 0.041) muscle coefficient on the DOM arm.
Conclusion:
The DOM shoulder exhibits a higher proportion of infraspinatus and lower trapezius muscle activation during the external rotation and abduction synergy. Also, the DOM shoulder has increased muscle activation of the teres major and latissimus dorsi during the internal rotation synergy, and increased muscle activation of the pectoralis major during the cross-body adduction synergy, compared with the NDOM shoulder.
Clinical Relevance:
By exploring these neuromuscular adaptations, the improved understanding of muscle synergy adaptations in baseball players will help optimize injury prevention and rehabilitation techniques.
The study was conducted mainly to examine the convergent validity of the Patient Reported Outcome Measurement Information System-Pediatric Physical Activity instrument (PROMIS
-PA) with step counts ...from wearable devices and another validated self-reported outcome measure. As a secondary aim, we explored the effect of different recall time frames (7-day, end-of-day EoD, and ecological momentary assessment EMA time frames during the day) in terms of their feasibility and associations with each other and with step counts. This was a prospective cohort study that examined the associations between measures of PA in school-age children and adolescents (
= 84, aged 10-20). The participants wore Fitbit devices for 7 consecutive days, and then completed the 7-day-recall PROMIS-PA short form and Youth Activity Profile (YAP). Additional analyses were completed in a sub-sample (
= 25, aged 11-18 years) using the PROMIS-PA for the EMA at five intervals during the day (shorter form) and at the EoD. In the total sample, the PROMIS-PA results showed positive moderate correlations with the YAP and average daily steps (
= 0.533,
< 0.001 and
= 0.346,
= 0.002, respectively). In the sub-sample, the 7-day PROMIS-PA was highly correlated with the averaged EMA or EoD ratings for the week, and moderately correlated with the daily step counts. These findings support the validity of the PROMIS-PA as a measure of self-reported physical activity. Adolescents demonstrated higher compliance rates and preference for the 7-day recall and EoD assessments compared to more frequent EMA reporting.
The E and B Experiment (EBEX) was a long-duration balloon-borne cosmic microwave background (CMB) polarimeter that flew over Antarctica in 2012. We describe the experiment's optical system, receiver, ...and polarimetric approach and report on their in-flight performance. EBEX had three frequency bands centered on 150, 250, and 410 GHz. To make efficient use of limited mass and space, we designed a 115 cm2 sr high-throughput optical system that had two ambient temperature mirrors and four antireflection-coated polyethylene lenses per focal plane. All frequency bands shared the same optical train. Polarimetry was achieved with a continuously rotating achromatic half-wave plate (AHWP) that was levitated with a superconducting magnetic bearing (SMB). This is the first use of an SMB in astrophysics. Rotation stability was 0.45% over a period of 10 hr, and angular position accuracy was 0 01. The measured modulation efficiency was above 90% for all bands. To our knowledge the 109% fractional bandwidth of the AHWP was the broadest implemented to date. The receiver, composed of one lens and the AHWP at a temperature of 4 K, the polarizing grid and other lenses at 1 K, and the two focal planes at 0.25 K, performed according to specifications, giving focal plane temperature stability with a fluctuation power spectrum that had a 1/f knee at 2 mHz. EBEX was the first balloon-borne instrument to implement technologies characteristic of modern CMB polarimeters, including high-throughput optical systems, and large arrays of transition edge sensor bolometric detectors with multiplexed readouts.
To determine the associations between trauma variables, acute phase-related variables, and patient-level characteristics with functional recovery during inpatient rehabilitation for individuals with ...spinal cord injury (SCI). The associations were evaluated by linking individuals' records between the Pennsylvania Trauma Systems Outcomes Study and the National SCI Model Systems databases.
Retrospective cohort analysis.
Two SCI Model Centers in Pennsylvania, United States.
We used a record linkage toolkit in Python to link 735 individuals with traumatic SCI between the databases. The percentage for true-match and error were 92.0% and 0.1%, respectively. The functional recovery during inpatient rehabilitation was determined in 604 individuals with SCI by ordinary least squares regression (OLS) and gradient boosting regression (GBR) analyses.
The OLS and GBR analyses indicated older age, greater impairment (SCI level combined with American Spinal Injury Association impairment scale), presence of diabetes mellitus, pulmonary complications during acute care, and longer length of stay at an inpatient rehabilitation facility were associated with lower functional recovery (OLS R
2
= 0.56 and GBR R
2
= 0.58).
Trauma and acute care variables in addition to patient characteristics were associated with functional recovery during inpatient rehabilitation in individuals with SCI. Further investigation is needed to understand the role of diabetes mellitus and pulmonary complications, which have not been previously associated with functional recovery in individuals with SCI.
The main aims of this study were to (1) create a patient-reported outcome measure (PROM) item bank for measuring the impact of upper quadrant edema (UQE) on physical function by calibrating responses ...to newly developed items; and (2) assess reliability, validity, and administration efficiency of scores based on computerized adaptive test (CAT) and 10-item short-form (SF) administration modes.
This was a retrospective study including data from patients treated in outpatient rehabilitation clinics for UQE that responded to all 27 candidate items at intake. Item response theory model assumptions of unidimensionality, local item independence, item fit, and presence of differential item functioning were evaluated. UQE-CAT- and UQE-SF-generated scores were assessed for reliability, validity, and administration efficiency.
The total cohort included 3486 patients (mean SD age = 61 13 years; range = 14-89 years). After removing 2 items, a 25-item solution was supported for its unidimensionality and fit to the item response theory model with reliability estimates of more than 0.93 for scores based on both CAT and SF administration modes. No items demonstrated differential item functioning. Scores discriminated among multiple patient groups in clinically logical ways and were moderately responsive to change with negligible floor and acceptable ceiling effects. CAT scores were generated using an average of 5.6 items (median = 5).
Scores on the UQE PROM were reliable, valid, and efficient for assessing perceived physical function of patients with upper quadrant edema; thus, the measure is suitable for research and routine clinical administration.
The newly developed UQE PROM is reliable and valid and offers efficient administration modes for assessing perceived physical function of patients with UQE caused by lymphatic and venous disorders, both for research and routine clinical care in busy outpatient rehabilitation settings. As an item response theory-based measure, the UQE PROM allows administration of condition-specific functional questions with low response burden for patients. This study supports a transition to PROMs that are based on modern measurement approaches to achieve high accuracy and efficiency.
Background: Altered hip and knee kinematics and joint coupling have been documented in runners with iliotibial band syndrome. Symptoms often present themselves after several minutes of running, yet ...the effect of fatigue warrants further exploration. The purpose of this study was to determine the effect of a run to fatigue in runners with iliotibial band syndrome, as compared to healthy controls. Methods: Twenty uninjured and 12 female runners with iliotibial band syndrome performed a treadmill run to fatigue. Prior-to and following a run to fatigue, overground running data were collected. Variables of interest included stance phase: peak hip adduction and internal rotation, peak hip abductor and external rotator joint moments and frontal-sagittal plane hip and knee joint coupling. Findings: Fatigue resulted in decreased peak hip adduction angles in injured runners. Fatigue did not affect injured runners differently than controls with respect to the remaining variables. Coupling differences did not exist between healthy and injured runners with respect to the loading or propulsive phases of stance. Interpretation: While clinicians often strengthen hip abductor muscles and provide gait re-training to decrease stance phase hip adduction, our results suggest that, when exerted, female runners with iliotibial band syndrome independently modify their running gait to decrease hip adduction, potentially as a result of pain. Fatigue did not have an effect on the remaining study variables. It is possible that reducing the length of the iliotibial band through minimizing hip adduction reduces pain, but the other variables examined are not sensitive to this phenomenon. (Autor).
•Turning difficulty is associated with advanced age.•Visual dependency affects sit-to-stand but not stand-to-sit in older adults.•Wearing an HMD even without the addition of a visual scene alters ...motor performance.
Older adults show greater postural instabilities under misleading visual cues relative to younger adults. We investigated the effects of age-related visual dependence on motor performance under increased attention demands by adding a motor task and visual stimulus to the Timed Up and Go (TUG) test sub-components.
We designed a cross-sectional quantitative study. Twenty-eight younger (n = 12) and older (n = 16) adults completed the TUG test while wearing a head-mounted display (HMD) that presented a visual stimulus and/or carrying a cup of water. Outcome measures were turning cadence; gait speed; pitch, yaw, and roll peak trunk velocities (PTVs); and acceleration ranges of sit-to-stand and stand-to-sit.
Wearing the HMD caused significant performance differences in the TUG test tasks due to age and visual dependence, although performance was lower across all groups with the HMD (p < 0.01). Older adults showed lower roll PTV in turning compared to younger adults (p = 0.03). Visually dependent older adults showed smaller mediolateral and vertical acceleration ranges (p < 0.04) in sit-to-stand compared to visually independent older adults.
The demand for orienting posture to a vertical position during sit-to-stand may differentiate older adults who are more visually dependent—and thus at greater fall risk— from those who are more visually independent. Age-related differences in turning behavior suggest a relationship with fall risk that warrants further investigation.
We report on measurements of the cosmic microwave background (CMB) and celestial polarization at 146 GHz made with the Atacama Cosmology Telescope Polarimeter (ACTPol) in its first three months of ...observing. Four regions of sky covering a total of 270 square degrees were mapped with an angular resolution of 1.3'. The map noise levels in the four regions are between 11 and 17 μK-arcmin. We present TT, TE, EE, TB, EB, and BB power spectra from three of these regions. The observed E-mode polarization power spectrum, displaying six acoustic peaks in the range 200 < ℓ < 3000, is an excellent fit to the prediction of the best-fit cosmological models from WMAP9+ACT and Planck data. The polarization power spectrum, which mainly reflects primordial plasma velocity perturbations, provides an independent determination of cosmological parameters consistent with those based on the temperature power spectrum, which results mostly from primordial density perturbations. We find that without masking any point sources in the EE data at ℓ < 9000, the Poisson tail of the EE power spectrum due to polarized point sources has an amplitude less than 2.4 μ {sup 2} at ℓ = 3000 at 95% confidence. Finally, we report that the Crab Nebula, an important polarization calibration source at microwave frequencies, has 8.7% polarization with an angle of 150.7{sup o} ± 0.6{sup o} when smoothed with a 5' Gaussian beam.
The study's purpose was to evaluate the concurrent validity of the Child Patient-Reported Outcomes Measurement Information System (PROMIS) PA with the Youth Activity Profile (YAP) and examine its ...relationship to PROMIS measures of sedentary behavior and fatigue. The PROMIS Pediatric Activity (PA) measure is a newly developed, valid instrument used to collect data on children's lived experiences of short bouts of moderate to rigorous physical activity.
Participants were ages 8 to 20 years attending a state fair. Child PROMIS measures-PA, Sedentary Behavior, and Fatigue-and the YAP were completed on an iPad.
The PROMIS PA and YAP had a positive correlation. The PROMIS PA was not associated with sedentary behavior or fatigue measurements.
As expected, the PROMIS PA and YAP measure-related PA constructs, the YAP focuses on energy expended while the PROMIS PA indicates perceived response to activity.
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