Validity and Efficacy of the Elite HRV Smartphone Application during Slow-Paced Breathing.

Slow-paced breathing is a clinical intervention used to increase heart rate variability (HRV). The practice is made more accessible via cost-free smartphone applications like Elite HRV. We investigated whether Elite HRV can accurately measure and augment HRV via its slow-paced breathing feature. Twenty young adults completed one counterbalanced cross-over protocol involving 10 min each of supine spontaneous (SPONT) and paced (PACED; 6 breaths·min-1) breathing while RR intervals were simultaneously recorded via a Polar H10 paired with Elite HRV and reference electrocardiography (ECG). Individual differences in HRV between devices were predominately skewed, reflecting a tendency for Elite HRV to underestimate ECG-derived values. Skewness was typically driven by a limited number of outliers as median bias values were ≤1.3 ms and relative agreement was ≥very large for time-domain parameters. Despite no significant bias and ≥large relative agreement for frequency-domain parameters, limits of agreement (LOAs) were excessively wide and tended to be wider during PACED for all HRV parameters. PACED significantly increased low-frequency power (LF) for Elite HRV and ECG, and between-condition differences showed very large relative agreement. Elite HRV-guided slow-paced breathing effectively increased LF values, but it demonstrated greater precision during SPONT and in computing time-domain HRV.

Reliability of Upper Extremity Functional Performance Tests for the Non-overhead Athlete.

Background: While there have been reliability studies conducted on several upper extremity functional performance tests (UEFPT), there are several complicating factors that inhibit the ability to draw definitive consensus about the reliability of the tests in both females and males. Having reliability estimates for UEFPT in the same cohort facilitates direct comparison of their relative and absolute reliability. Purpose: To establish the test-retest reliability of the closed kinetic chain upper extremity stability test (CKCUEST), seated medicine ball chest pass test (SMBCPT) and hands-release push-up test (HRPUT) in a cohort of males and females with a history of non-overhead sport participation. A secondary purpose was to examine the associations between the three UEFPT. Study Design: Test-retest reliability, single cohort study. Methods: Forty adults (20 females, 20 males) with a history of non-overhead sport participation completed three UEFPT during two data collection sessions three to seven days apart. Measures of systematic bias, absolute reliability and relative reliability were computed between the sessions. Additionally, correlational analyses were conducted between the three UEFPT. Results: Only the UECKCST (both sexes) demonstrated significant (p≤ 0.003) second session performance improvements. All three tests exhibited excellent relative reliability (intraclass correlational coefficients ≥ 0.823) and except for the HRPUT in males, coefficients of variation were all below 8.8%. Except for a significant relationship (r=.691, p=0.001) between the UECKCST and SMBCPT for the females there were no other associations between the three UEFPT. Conclusion: All three UEFPT demonstrated sufficient reliability. Thus, all three assessments can be used for serial assessments to progress a patient through rehabilitation as well as contribute to the criteria used in making return to sport decisions. Level of Evidence: 3.

Reliability of Upper Extremity Functional Performance Tests for Overhead Sports Activities.

Background: There is lack of consensus on which tests, particularly upper extremity functional performance tests (FPT) that should be used for clinical decision making to progress a patient through a rehabilitation program or criteria for return to sport (RTS). Consequently, there is a need for tests with good psychometric properties that can be administered with minimal equipment and time. Purpose: (1) To establish the intersession reliability of several open kinetic chain FPT in healthy young adults with a history of overhead sport participation. (2) To examine the intersession reliability of the limb symmetry indices (LSI) from each test. Study Design: Test-retest reliability, single cohort study. Methods: Forty adults (20 males, 20 females) completed four upper extremity FPT during two data collection sessions three to seven days apart: 1) prone medicine ball drop test 90°shoulder abduction (PMBDT 90°), 2) prone medicine ball drop test 90°shoulder abduction/90° elbow flexion (PMBDT 90°-90°), 3) half-kneeling medicine ball rebound test (HKMBRT), 4) seated single arm shot put test (SSASPT). Measures of systematic bias, absolute reliability and relative reliability were computed between the sessions for both the original test scores and LSI. Results: Except for the SSASPT, all tests demonstrated significant (p ≤ 0.030) improvements in performance during the second session. Generally, for the medicine ball drop/rebound tests, the absolute reliability was the highest (less random error) for the HKMBRT, next the PMBDT 90°followed by PMBDT 90°-90°. Excellent relative reliability existed for the PMBDT 90°, HKMBRT, and SSASPT, whereas fair to excellent relative reliability for the PMBDT 90°-90°. The SSASPT LSI revealed the highest relative and absolute reliability. Conclusion: Two tests, HKMBRT and SSASPT demonstrated sufficient reliability; therefore, the authors' recommend those tests can be used for serial assessments to advance a patient through a rehabilitation program as well as criteria for progression to RTS. Level of Evidence: 3.

Blood alcohol concentration as a measure of risk among pedestrian fatalities in the U.S., 2016-2020.

OBJECTIVE: In the United States, deaths among pedestrians have increased dramatically since 2009 relative to other vulnerable road users, with substance use described as an important risk factor. This study aimed to explore blood alcohol concentrations (BAC g/dL) among pedestrian fatalities in the United States between 2016 and 2020. Exploring the presence of alcohol among pedestrian cases will support targeted interventions designed to reduce risk. METHODS: This study utilized pedestrian fatality and alcohol screening data provided by the Fatality Analysis Reporting System (FARS). Logistic models were examined to identify statistical associations (ORs, 95% CI) by age, race, and sex relative to positive BAC exposure (BAC > 0.0 g/dL), mild exposure (BAC > 0.0 < .079 g/dL), moderate to severe alcohol exposure (BAC 0.08-.299 g/dL), and severe exposure (BAC ≥ 0.30 g/dL). RESULTS: Between 2016 and 2020, 33,375 pedestrian fatalities were reported to FARS with 75.1% of cases retained for analysis (n = 25,077). Fatalities were more likely to be White (69.3%), male (69.9%), and between 25-64 years of age (67.3%). 74.0% of fatalities were tested for alcohol, with 40.9% screening positive. Females, cases ≥ 75 years of age, and those identified as Asians reported the lowest odds of being positive for alcohol exposure. CONCLUSIONS: Results suggest an ongoing threat to pedestrians due to alcohol consumption and that exposure odds vary by demographic characteristics. Unfortunately, analytical approaches to understanding the roles played by drugs and alcohol among vulnerable road users tend to be marginalized in the literature. Analytical, evidence-based investigations are needed to curtail the risk of pedestrian fatalities in the U.S.

Limb Dominance Effects on Seated Single-Arm Shot-Put Limb Symmetry Indices Following Shoulder Rehabilitation.

CONTEXT: Typically, most clinical return to activity guidelines recommend that an injured shoulder achieve a 90% to 100% functional performance test limb symmetry index (LSI); however, as previous research demonstrated a 103% to 111% dominant limb bias in seated single-arm shot-put test (SSASPT) performance, the typical criteria might not be appropriate for interpreting SSASPT LSI. Thus, the current objective was to evaluate SSASP LSI differences between dominant and nondominant involved shoulders and to determine how many patients met the suggested 90% to 100% LSI criteria, as well as the 103% for dominant (89% for nondominant) normative SSASPT threshold reported in the literature, at the time of discharge. DESIGN: Cross-sectional. METHODS: Patients with shoulder injury or surgery (n = 78) completed the SSASPT at the time of discharge from rehabilitation and were grouped according to whether the involved shoulder was the dominant (n = 42) or nondominant (n = 32) limb. LSI (involved/uninvolved × 100) was computed from the average of 3 SSASPT trial distances completed with each limb. RESULTS: The LSI for the nondominant involved group (88.9% [12.4%]) was significantly less (confidence intervalDiff, -12.1% to -22.1%) than the dominant involved group (106.0% [9.3%]). While 95.2% of patients in the dominant involved group exhibited LSI > 90%, only 43.8% of patients in the nondominant involved group attained LSI > 90%. Across the entire cohort, the odds of a nondominant involved LSI being below the respective SSASPT normative range were 2.04 (95% confidence interval, 0.80-5.21) times higher than the odds of a dominant involved LSI being below the normative range. CONCLUSIONS: Patients with dominant limb involvement exhibited higher LSI than patients with nondominant limb involvement at discharge from rehabilitation. Particularly when the nondominant shoulder is involved, these results suggest that patients with shoulder injury and surgery may require longer rehabilitation to attain higher levels of upper-extremity function.

Effects of Kettlebell Load on Joint Kinetics and Global Characteristics during Overhead Swings in Women.

This study sought to identify the changes in ankle, knee, and hip joint kinetics with increasing load while performing the kettlebell overhead swing (OHS). Women (n = 18, age: 29.4 ± 5.3 years, 69.7 ± 8.9 kg) with a minimum of 6 months of kettlebell swing training experience performed fifteen repetitions of the kettlebell OHS with three different kettlebell masses (8 kg, 12 kg, 16 kg) in a counterbalanced order. Ankle, knee, and hip joint kinematics were captured within a 12-camera infrared motion capture space, while standing atop two force plates collecting ground reaction force (GRF) data. Post hoc results of statistically significant joint by mass interactions (p < 0.05) of the net joint moment impulse, work, and peak power revealed the hip demonstrating the greatest increase in response to load, followed by the ankle (p < 0.05). The knee joint kinetics changed very little between the masses. Pairwise post hoc comparisons between the joints at each mass level support the kettlebell OHS as being a hip dominant exercise, with the knee making the second largest contribution, despite contributions not changing across kettlebell masses. Collectively, these results provide practitioners with objective evidence regarding the mechanical demands and effects of load changes on the kettlebell OHS.

Self-recorded heart rate variability profiles are associated with health and lifestyle markers in young adults.

PURPOSE: To quantify associations between self-recorded heart rate variability (HRV) profiles and various health and lifestyle markers in young adults. METHODS: Otherwise healthy volunteers (n = 40, 50% male) recorded 60-s, post-waking HRV with a cost-free mobile application in supine and standing positions for 7 days. The 7-day average and coefficient of variation (CV, reflects daily fluctuation) for the mean RR interval and root mean square of successive differences (LnRMSSD) were assessed. 7-day sleep duration and physical activity profiles were characterized via wrist-worn accelerometer. Subsequent laboratory assessments included aerobic fitness ([Formula: see text]O2peak) and markers of cardiovascular, metabolic, and psychoemotional health. Associations were evaluated before and after [Formula: see text]O2peak adjustment. RESULTS: Bivariate correlations (P < 0.05) demonstrated that higher 7-day averages and/or lower CV values were associated with higher activity levels and superior cardiovascular (lower systolic and diastolic blood pressure [BP] and aortic stiffness [cf-PWV]), metabolic (lower body fat percentage, fasting glucose, and low-density lipoprotein cholesterol [LDL-C]), and psychoemotional health (lower perceived stress) markers, with some variation between sexes and recording position. In males, associations between HRV parameters and cf-PWV remained significant following [Formula: see text]O2peak adjustment (P < 0.05). In females, HRV parameters were associated (P < 0.05) with numerous cardiovascular (systolic and diastolic BP, cf-PWV) and metabolic (fasting glucose and LDL-C) parameters following [Formula: see text]O2peak adjustment. CONCLUSIONS: Higher or more stable supine and standing HRV were generally associated with superior health and lifestyle markers in males and females. These findings lay groundwork for future investigation into the usefulness of self-recorded ultra-short HRV as a health-promoting behavior-modification tool in young adults.

Sleep duration irregularity is associated with elevated blood pressure in young adults.

Sleep irregularity (i.e., highly variable sleep patterns) is an emerging risk factor for cardiometabolic disease. Though irregular sleep patterns are common among young adults, the cardiometabolic health (CMH) repercussions of sleep irregularity in this population are unclear. We examined associations between sleep duration and irregularity with measures of CMH in 44 (24 M/20 F, 23 ± 5y, BMI 26 ± 4 kg/m2, blood pressure (BP): 125/71 ± 14/9 mmHg) young adults. Participants wore actigraphy monitors for seven-days and sleep duration irregularity was operationalized as the standard deviation of nightly sleep duration (sleep SD). CMH variables of interest included brachial and aortic BP, arterial stiffness (cf-PWV), augmentation index (AIx75), and fasting blood glucose and lipids. Associations between sleep duration and sleep SD with CMH variables were assessed via correlations adjusted for sex and BMI. Sleep duration generally was not associated with CMH indices. However, sleep SD was associated with brachial systolic (r = 0.433, p = .027) and diastolic BP (r = 0.415, p = .035). Similarly, sleep duration SD was associated with aortic systolic BP (r = 0.447, p = .022). Our findings show that sleep irregularity, but not duration, is associated with higher brachial and central BP in young adults.Abbreviations: AIx75: augmentation index at a heart rate of 75 beats per minute; BP: blood pressure; CMH: cardiometabolic health; cf-PWV: carotid-femoral pulse wave velocity; DXA: dual x-ray absorptiometry; mg/dl: milligrams per deciliter; PWA: pulse wave analysis; PWV: pulse wave velocity; sleep duration SD: standard deviation of nightly sleep duration.

Relationships between the seated single arm shot put test and Quick-DASH in patients being discharged from physical therapy.

BACKGROUND: Research examining the relationship between patient reported outcomes (PRO) and upper extremity functional performance tests (UEFPT) in patients with shoulder pathology are limited. OBJECTIVE: To assess the relationship between the seated single arm shot put test (SSASPT) and the PRO Quick-Disabilities of Arm, Shoulder, and Hand (DASH) in patients being discharged from physical therapy after shoulder injury or surgery. METHODS: Six physical therapists who regularly use the SSASPT and DASH from six different clinical sites provided SSASPT scores and completed Quick-DASH forms on 75 patients being discharged from rehabilitation following shoulder injury or surgery. Patients were grouped according to whether the involved shoulder was the dominant (n = 43) or nondominant (n = 32) limb. Three separate simple linear regression models, whole cohort and two patient groups, were created to determine the magnitude of the relationships (standardized betas) and change (betas) between DASH scores and the SSASPT limb symmetry index (LSI). RESULTS: Neither whole cohort nor two groups exhibited statistically significant (P > .05) relationships between LSI and Quick-DASH scores based upon the standardized betas (-0.197-0.038). Additionally, neither the standardized betas (z = 1.49, P = .135) nor betas (z = 1.28, P = .200) were statistically different between the two groups. CONCLUSIONS: The current study revealed no association between SSASPT and the Quick-DASH at discharge from physical therapy following shoulder injury or surgery. Consequently, it may be important to perform a battery of tests that include both subjective PRO and objective UEFPT tests to obtain a comprehensive perspective of the patient's functional and perceived status.

The Influence of Hip Flexion and Isokinetic Velocity on Hamstrings-Quadriceps Strength Ratios in Healthy Females.

Context: Measurements of the concentric hamstrings-quadriceps strength ratio (Hc:Qc) are almost exclusively recorded in the upright, seated position (hip flexion 80-100°) on an isokinetic dynamometer at angular velocities ranging from 30°/s to 360°/s. Further, there is a scarcity of data examining Hc:Qc ratio in females. Objective: To compare the effects of hip-flexion position (0°, 45°, and 90°) and isokinetic velocity (60°/s, 180°/s, and 300°/s) on knee-extension and knee-flexion torques and the Hc:Qc ratio of females. Design: Single-session, repeated measures. Setting: Biomechanics laboratory. Participants: Twenty-seven healthy young female adults. Intervention: Participants completed five repetitions of isokinetic, concentric knee-flexion and knee-extension at hip flexions of 0° (supine), 45° (midrange), and 90° (traditional), at 60°/s, 180°/s, and 300°/s. Main Outcome Measures: Knee extension and flexion average peak torque (PT) and resultant Hc:Qc ratios. Results: Knee-extension average PT was significantly influenced by isokinetic velocity but hip-flexion position was not. Compared to 90°, knee-flexion average PT was significantly greater in the 45° and 0° hip positions, coupled with greater average PT decreases between 60°/s and 180°/s than between 180°/s and 300°/s. Hc:Qc ratios in the 0° position were significantly greater than in the other positions and increased significantly as testing velocity increased. Conclusions: Exclusively using a seated, upright position during knee isokinetic testing on females may misrepresent knee strength at more-functional hip positions. We recommend evaluating isokinetic knee strength using a supine position to better reflect hip positions during daily and sporting activities, throughout movement specific velocities.

Globally altered sleep patterns and physical activity levels by confinement in 5056 individuals: ECLB COVID-19 international online survey.

Symptoms of psychological distress and disorder have been widely reported in people under quarantine during the COVID-19 pandemic; in addition to severe disruption of peoples' daily activity and sleep patterns. This study investigates the association between physical-activity levels and sleep patterns in quarantined individuals. An international Google online survey was launched in April 6th, 2020 for 12-weeks. Forty-one research organizations from Europe, North-Africa, Western-Asia, and the Americas promoted the survey through their networks to the general society, which was made available in 14 languages. The survey was presented in a differential format with questions related to responses "before" and "during" the confinement period. Participants responded to the Pittsburgh Sleep Quality Index (PSQI) questionnaire and the short form of the International Physical Activity Questionnaire. 5056 replies (59.4% female), from Europe (46.4%), Western-Asia (25.4%), America (14.8%) and North-Africa (13.3%) were analysed. The COVID-19 home confinement led to impaired sleep quality, as evidenced by the increase in the global PSQI score (4.37 ± 2.71 before home confinement vs. 5.32 ± 3.23 during home confinement) (p < 0.001). The frequency of individuals experiencing a good sleep decreased from 61% (n = 3063) before home confinement to 48% (n = 2405) during home confinement with highly active individuals experienced better sleep quality (p < 0.001) in both conditions. Time spent engaged in all physical-activity and the metabolic equivalent of task in each physical-activity category (i.e., vigorous, moderate, walking) decreased significantly during COVID-19 home confinement (p < 0.001). The number of hours of daily-sitting increased by ~2 hours/days during home confinement (p < 0.001). COVID-19 home confinement resulted in significantly negative alterations in sleep patterns and physical-activity levels. To maintain health during home confinement, physical-activity promotion and sleep hygiene education and support are strongly warranted.

The Influence of Active Hamstring Stiffness on Markers of Isotonic Muscle Performance.

BACKGROUND: Previous research demonstrates hamstring muscle-tendon stiffness (HMTS) influences isometric strength, landing biomechanics and architectural tissue properties. However, the influence on kinetics & kinematics during other modes of strength testing (isotonic dynamometry) has yet to be established. PURPOSE: Investigate how HMTS influences kinetics and kinematics during a novel isotonic muscle performance test which has never been done for the hamstrings. Previous work using dynamometry has been limited to isometric or isokinetic contractions, so the novelty arises from our custom isotonic protocol which allows quantitative assessment of the stretch-shortening cycle. METHODS: Twenty-six recreationally active individuals (15 males, 11 females, 23.8 ± 2.5 years) completed baseline testing for anthropometry and maximum isometric hamstring strength (MVIC). At least 48 h later, subjects completed a measure of HMTS (damped oscillation technique) followed by an isotonic knee flexion test (eccentric velocity 180°/s; concentric torque 25% of MVIC). Separate linear regression models with examination of residuals were conducted between HMTS and each muscle performance variable. Standardized coefficients determined the magnitude of the relationships. RESULTS: Significance was found for all outcome variables tested. HMTS and rate of torque development demonstrated the strongest relationship followed by isotonic concentric peak torque. The weakest relationship observed was with isometric peak torque. CONCLUSIONS: These findings build off previous work quantifying HMTS by showing HMTS more strongly relates to dynamic versus static muscle testing and identifies the potential clinical utility of isotonic dynamometry.

Biomechanical Differences Between the Bulgarian Split-Squat and Back Squat.

The Bulgarian split squat (BSS) is a unilateral lower extremity strength exercise; however, the mechanical demands have not been fully elucidated. The purpose of this study was to compare ankle, knee, and hip joint net joint moment impulse (NJMI), work (NJW), peak net joint moment (NJM) and peak displacement between the BSS and traditional bilateral back squat (BS). Following a practice and 1-repetition maximum (1-RM) session, 2x3 BS (70% 1-RM) and BSS (35% 1-RM) were completed by twenty resistance trained males (24.20 ± 2.50 yrs, 1.76 ± 0.06m, 85.3 ± 13.90 kg). Significant squat type x joint interactions were revealed for NJMI (p < 0.001), NJW (p < 0.001), peak NJM (p < 0.001), and peak displacement (p = 0.011). For both squats, hip NJMI, NJW, and peak NJM was significantly greater than both ankle (d = 5.50-9.40) and knee (d = 7.50-8.50). While knee NJMI (d = 2.80) and peak NJM (d = 2.10) during the BSS was statistically less compared to ankle, during BS knee NJMI was statistically greater than ankle (d = 3.00). Ankle and knee NJW were statistically similar during BSS (d = 0.30), whereas knee NJW was statistically greater than ankle during BS (d = 3.20). Comparing between squat types within each joint demonstrated statistically equal peak displacement for the ankle (d = 0.14) and hip (d = 0.11), whereas knee joint peak displacement was significantly less for the BSS compared to BS (d = 0.82). Both the BSS and BS are hip dominant exercises. The BSS may best be used in circumstances to focus on hip extension while minimizing the knee joint demands, such as the early phases of knee rehabilitation or when addressing isolated hip extension deficiencies.

Effects of home confinement on mental health and lifestyle behaviours during the COVID-19 outbreak: insights from the ECLB-COVID19 multicentre study.

Although recognised as effective measures to curb the spread of the COVID-19 outbreak, social distancing and self-isolation have been suggested to generate a burden throughout the population. To provide scientific data to help identify risk factors for the psychosocial strain during the COVID-19 outbreak, an international cross-disciplinary online survey was circulated in April 2020. This report outlines the mental, emotional and behavioural consequences of COVID-19 home confinement. The ECLB-COVID19 electronic survey was designed by a steering group of multidisciplinary scientists, following a structured review of the literature. The survey was uploaded and shared on the Google online survey platform and was promoted by thirty-five research organizations from Europe, North Africa, Western Asia and the Americas. Questions were presented in a differential format with questions related to responses "before" and "during" the confinement period. 1047 replies (54% women) from Western Asia (36%), North Africa (40%), Europe (21%) and other continents (3%) were analysed. The COVID-19 home confinement evoked a negative effect on mental wellbeing and emotional status (P < 0.001; 0.43 ≤ d ≤ 0.65) with a greater proportion of individuals experiencing psychosocial and emotional disorders (+10% to +16.5%). These psychosocial tolls were associated with unhealthy lifestyle behaviours with a greater proportion of individuals experiencing (i) physical (+15.2%) and social (+71.2%) inactivity, (ii) poor sleep quality (+12.8%), (iii) unhealthy diet behaviours (+10%), and (iv) unemployment (6%). Conversely, participants demonstrated a greater use (+15%) of technology during the confinement period. These findings elucidate the risk of psychosocial strain during the COVID-19 home confinement period and provide a clear remit for the urgent implementation of technology-based intervention to foster an Active and Healthy Confinement Lifestyle AHCL).

Sleep Quality and Physical Activity as Predictors of Mental Wellbeing Variance in Older Adults during COVID-19 Lockdown: ECLB COVID-19 International Online Survey.

BACKGROUND: The COVID-19 lockdown could engender disruption to lifestyle behaviors, thus impairing mental wellbeing in the general population. This study investigated whether sociodemographic variables, changes in physical activity, and sleep quality from pre- to during lockdown were predictors of change in mental wellbeing in quarantined older adults. METHODS: A 12-week international online survey was launched in 14 languages on 6 April 2020. Forty-one research institutions from Europe, Western-Asia, North-Africa, and the Americas, promoted the survey. The survey was presented in a differential format with questions related to responses "pre" and "during" the lockdown period. Participants responded to the Short Warwick-Edinburgh Mental Wellbeing Scale, the Pittsburgh Sleep Quality Index (PSQI) questionnaire, and the short form of the International Physical Activity Questionnaire. RESULTS: Replies from older adults (aged >55 years, n = 517), mainly from Europe (50.1%), Western-Asia (6.8%), America (30%), and North-Africa (9.3%) were analyzed. The COVID-19 lockdown led to significantly decreased mental wellbeing, sleep quality, and total physical activity energy expenditure levels (all p < 0.001). Regression analysis showed that the change in total PSQI score and total physical activity energy expenditure (F(2, 514) = 66.41 p < 0.001) were significant predictors of the decrease in mental wellbeing from pre- to during lockdown (p < 0.001, R2: 0.20). CONCLUSION: COVID-19 lockdown deleteriously affected physical activity and sleep patterns. Furthermore, change in the total PSQI score and total physical activity energy expenditure were significant predictors for the decrease in mental wellbeing.

Reliability and validity of a novel Isokinetic Knee Dynamometer System.

PURPOSE: The aim of this work was to determine the intersession reliability and validity of a recently developed prototype Isokinetic Knee Dynamometer to assess isokinetic knee extension and flexion peak moments compared to a Biodex System 4 dynamometer. METHODS: Thirty- -five healthy participants performed two sessions (48-h separation) of bilateral concentric isokinetic knee extension and flexion on both isokinetic devices at 60 °/s (6 repetitions), 180 °/s (10 repetitions) and 240 °/s (15 repetitions). Dynamometer and limb order were randomized among participants while peak moment of each set was used for data analysis. RESULTS: The Isokinetic Knee Dynamometer had excellent relative reliability, comparable to the System 4, and both systems displayed acceptable absolute reliability. Proportional biases were observed favoring the System 4 during knee extension of both limbs at 60 °/s and the dominant limb at 180 °/s, and fixed biases favoring the Isokinetic Knee Dynamometer in seven conditions. Relative agreement between systems was good across all test conditions with the majority demonstrating excellent agreement. CONCLUSIONS: These data support the Isokinetic Knee Dynamometer as a reliable and valid knee isokinetic testing system. Due to its reduced system complexity, space requirements, and production cost, the Isokinetic Knee Dynamometer may increase the clinical utilization of isokinetic knee assessments. Finally, these data fill an existing isokinetics literature void with the results supporting similar and acceptable measurement properties jointly for dominant and non-dominant limbs and at the higher testing velocities considered.

COVID-19 Home Confinement Negatively Impacts Social Participation and Life Satisfaction: A Worldwide Multicenter Study.

Public health recommendations and governmental measures during the new coronavirus disease (COVID-19) pandemic have enforced numerous restrictions on daily living including social distancing, isolation, and home confinement. While these measures are imperative to mitigate spreading of COVID-19, the impact of these restrictions on psychosocial health is undefined. Therefore, an international online survey was launched in April 2020 to elucidate the behavioral and lifestyle consequences of COVID-19 restrictions. This report presents the preliminary results from more than one thousand responders on social participation and life satisfaction. METHODS: Thirty-five research organizations from Europe, North-Africa, Western Asia, and the Americas promoted the survey through their networks to the general society, in 7 languages (English, German, French, Arabic, Spanish, Portuguese, and Slovenian). Questions were presented in a differential format with questions related to responses "before" and "during" confinement conditions. RESULTS: 1047 participations (54% women) from Asia (36%), Africa (40%), Europe (21%), and others (3%) were included in the analysis. Findings revealed psychosocial strain during the enforced COVID-19 home confinement. Large decreases (p < 0.001) in the amount of social activity through family (-58%), friends/neighbors (-44.9%), or entertainment (-46.7%) were triggered by the enforced confinement. These negative effects on social participation were also associated with lower life satisfaction (-30.5%) during the confinement period. Conversely, the social contact score through digital technologies significantly increased (p < 0.001) during the confinement period with more individuals (+24.8%) being socially connected through digital technology. CONCLUSION: These preliminary findings elucidate the risk of psychosocial strain during the early COVID-19 home confinement period in 2020. Therefore, in order to mitigate the negative psychosocial effects of home confinement, implementation of national strategies focused on promoting social inclusion through a technology-based solution is strongly suggested.

Relationship Between Seated Single-Arm Shot Put and Isokinetic Shoulder Flexion and Elbow Extension Strength.

CONTEXT: A recent report demonstrated moderate to strong relationships between seated single-arm shot-put (SSASP) test performance and isokinetic pushing forces at varying velocities, directly supporting the SSASP test as a reflection of multijoint upper-extremity strength. Yet, no previous work appears to have assessed whether the SSASP test is more reflective of shoulder flexion or elbow extension strength. OBJECTIVE: To examine the relationship between isokinetic shoulder flexion and elbow extension strength and SSASP test performance and to compare limb symmetry indices (LSI) between the 2 tests. DESIGN: Correlational design. SETTING: Biomechanics laboratory. Patients (or Other Participants): A total of 30 healthy and physically active young adults. INTERVENTION(S): Participants completed the SSASP test and concentric isokinetic (60°/s and 180°/s) shoulder flexion and elbow extension using their dominant and nondominant arms. MAIN OUTCOME MEASURES: SSASP test performance and isokinetic shoulder flexion and elbow extension peak torques as well as LSI between the 2 tests. RESULTS: Strong relationships were observed between SSASP ranges and isokinetic peak torques at each velocity for both shoulder and elbow (r ≥ .804, P < .001). While the Bland-Altman results on the LSI only demonstrated a significant bias for the shoulder (60°/s, P = .009), limits of agreement results demonstrated extremely wide intervals (32.5%-52.1%). CONCLUSIONS: The SSASP test is a multijoint upper-extremity functional performance test that is reflective of equal shoulder flexion and elbow extension contributions; however, there was large variability regarding the agreement between the SSASP LSI and isokinetic shoulder and elbow strength LSI.

Self-reported sleep quality is associated with gut microbiome composition in young, healthy individuals: a pilot study.

OBJECTIVES: The microbiota-gut-brain axis is an intricate communication network that is emerging as a key modulator of psychological and physiological wellbeing. Recent pioneering work in the field has suggested a possible link between gut microbiome composition with sleep, an evolutionarily conserved behavior demonstrated to play a critical role in health. This study is the first to address relationships between self-reported sleep habits and gut microbiome composition in young, healthy individuals. METHODS: A total of 28 young, healthy subjects (17 males/11 females; 29.8 ± 10.4 years) that were free of metabolic or cardiovascular disease, and that did not take sleep medication or antibiotics within the past six months were included in the study. Relationships between self-reported sleep quality, obtained using the Pittsburgh Sleep Quality Index (PSQI), with microbial diversity (Shannon Index), the Firmicutes/Bacteroidetes (F/B) ratio, and select bacterial taxa were assessed. RESULTS: Alpha diversity (r = -0.50) and F/B ratio (r = -0.47) were inversely associated (P < 0.05) with the PSQI score. Ten bacterial taxa were associated (P < 0.05) with the PSQI score, including genus-level Blautia (r = -0.57), Ruminococcus (r = -0.39), and Prevotella (r = 0.39). CONCLUSIONS: In young healthy individuals, self-reported sleep quality was positively associated with microbial diversity. We also observed a positive association between sleep quality with F/B ratio, seemingly due to a greater relative abundance of Blautia and Ruminococcus (Firmicutes) and lower proportions of Prevotella (Bacteroidetes) in individuals reporting superior sleep quality. Future studies are encouraged to evaluate mechanistic links between the gut microbiome with sleep, as well as the health implications of this relationship.

Biomechanical analysis of the closed kinetic chain upper extremity stability test in healthy young adults.

OBJECTIVES: To compare kinematic and ground reaction force (GRF) patterns between the dominant and non-dominant limbs in males and females conducting the closed kinetic chain upper extremity stability test (CKCUEST). DESIGN: Descriptive. SETTING: Biomechanics laboratory. PARTICIPANTS: Sixteen male and sixteen female healthy and physically active young adults. MAIN OUTCOME MEASURES: Hand contact and flight times, peak and average vertical (vGRF) and medial-lateral (mlGRF) ground reaction forces, medial-lateral (ML) distance and ML velocity per repetition, three-dimensional (3D) distance and 3D velocity per repetition, and average number of touches per trial during the CKCUEST. RESULTS: Only peak and average mlGRF were statistically different between limbs. Males and females were statistically different across every measured variable. ML and 3D velocities were the only variables strongly correlated to the number of touches achieved. CONCLUSIONS: Both sexes were symmetrical between limbs in all but mlGRF; however, there were distinct differences in both kinematics and GRF patterns between sexes that may be attributed to differences in the testing position between males and females.