Sit-to-stand Time Research Articles

The relationship between muscle quality index and physical function in older adults

BACKGROUND: The muscle quality index (MQI) has been proposed as a diagnostic tool to detect individuals at risk of limited physical function. OBJECTIVE: Our goal was to examine the relationship of the MQI with physical function and compare its predictive ability with other muscle parameters of strength and mass in an older population. METHODS: Sixty-eight healthy older adults (34 male, 34 female) aged between 69 and 89 years were tested for body composition, MQI, maximum isokinetic concentric KES and physical function including sit-to-stand (STS) time, normal and maximum walking speed (WS), Timed Up and Go (TUG) and static balance. Pearson’s correlation was applied to examine the relationship between muscle parameters. Linear regression analysis including age and sex as additional covariates was performed to assess their predictive ability for physical functions. RESULTS: MQI correlated significantly with relative KES (r= 0.611, p< 0.001), total KES (r= 0.829, p< 0.001) and leg lean tissue mass (r= 0.690, p< 0.001). The MQI was not a significant predictor for any physical function (p> 0.05). STS time was a significant predictor for normal WS and TUG time (p< 0.001). Relative KES was a significant predictor for all physical functions except static balance (p< 0.001). No muscle parameter and only age was a significant predictor for static balance. Models explained 20.4%–57.3% of variances of dependent variables. CONCLUSIONS: The MQI is a useful tool to assess leg lean tissue mass and strength of the knee extensor muscles and outperforms STS time. However, STS time and relative KES are more closely related to physical function than the MQI.

Development and assessment of test-retest reliability of a new field test to evaluate lower-limb muscle fatigability in young adults

We aimed to develop a new field test to evaluate lower-limb muscle fatigability in young adults. In Experiment–A, we developed and determined the ability of an intermittent isometric wall-squat test to induce progressive level of muscle fatigability, as detected by the kinetics of changes in squat-jump height (SJH) and sit-to-stand time (STST) computed using two smartphone applications for feasibility purposes. In Experiment–B, participants performed the same test on two different days for reliability assessment. Kinetics of changes in our fatigability indicators were registered at isotime, exhaustion, and Post2min. The minimal detectable change (MDC95) and the absolute (CVTE) and relative (ICC3-1) reliability coefficients were assessed. In Experiment–A, we reported a progressive decrease in performance for SJH and STST throughout the task, reaching at exhaustion mean changes of −22±11% and +31±13%. Individual data-analysis showed decrease in performance for SJH and STST greater than the MDC95 in 85% and 95% of participants. In Experiment–B, changes in our fatigability indicators demonstrated excellent inter-session reliability at isotime, exhaustion and Post2min for SJH (ICC3-1 > 0.97; CVTE < 7.5%) and STST (ICC3-1 > 0.92; CVTE < 3.3%). This test is feasible and reliable, making it very promising for evaluating muscle fatigability in applied (e.g. clinical) and laboratory settings.

Evaluation of Sit-to-Stand Movement Focusing on Kinematics, Kinetics, and Muscle Activity after Modern Total Knee Arthroplasty

The sit-to-stand (STS) movement is important in improving satisfaction after total knee arthroplasty (TKA). Reports on motion analysis using a combination of motion capture systems, force plates, and surface electromyography after TKA are limited. We aimed to compare the STS movement of patients aged over 60 who underwent modern and conventional TKA with more than 6 months of postoperative follow-up. Ten patients underwent surgery with a modern implant (Group I: Smith and Nephew JOURNEY II, Memphis, TN, USA), and ten with a conventional implant (Group II: Smith and Nephew LEGION, Memphis, TN, USA). STS movement kinematics and kinetic data were measured by synchronising a motion capture system with a force plate. Surface electromyography was used to measure the muscle activity. STS time was shorter in Group I than in Group II. Maximum knee-extension angular velocity and maximum knee-extension moment were greater in Group I than in Group II. Electromyography revealed that Group I tended to have less activity in the quadriceps femoris than Group II. Group II had a greater hip-extension moment and vertical ground reaction force, and the hip joint seemed to compensate for knee function. Group I possibly used the quadriceps muscle more effectively, due to the implant shape.

Validation of Gait Measurements on Short-Distance Walkways Using Azure Kinect DK in Patients Receiving Chronic Hemodialysis.

Muscle dysfunction, skeletal muscle fibrosis, and disability are associated with weakness in patients with end-stage renal disease. The main purpose of this study was to validate the effectiveness of a proposed system for gait monitoring on short-distance 1.5 m walkways in a dialysis center. Gaits with reduced speed and stride length, long sit-to-stand time (SST), two forward angles, and two unbalanced gait regions are defined in the proposed Kinect v3 gait measurement and analysis system (K3S) and have been considered clinical features in end-stage renal disease (ESRD) associated with poor dialysis outcomes. The stride and pace calibrations of the Kinect v3 system are based on the Zeno Walkway. Its single rating intraclass correlation (ICC) for the stride is 0.990, and its single rating ICC for the pace is 0.920. The SST calibration of Kinect v3 is based on a pressure insole; its single rating ICC for the SST is 0.871. A total of 75 patients on chronic dialysis underwent gait measurement and analysis during walking and weighing actions. After dialysis, patients demonstrated a smaller stride (p < 0.001) and longer SST (p < 0.001). The results demonstrate that patients' physical fitness was greatly reduced after dialysis. This study ensures patients' adequate physical gait strength to cope with the dialysis-associated physical exhaustion risk by tracing gait outliers. As decreased stride and pace are associated with an increased risk of falls, further studies are warranted to evaluate the clinical benefits of monitoring gait with the proposed reliable and valid system in order to reduce fall risk in hemodialysis patients.

Increased Fatigability in Women With Persistent Cancer-Related Fatigue After Breast Cancer Treatment: A Pilot Study

Purpose: To examine whether survivors of breast cancer (SBC) with persistent cancer-related fatigue (CRF) have greater fatigability than their nonfatigued counterparts. Methods: Measures of fatigability, including endurance, perceived exertion, lower extremity muscle force and power, and sit-to-stand time (STST), were assessed in 43 women (21 with persistent CRF) after a sit-to-stand fatigue (STSF) task. Group differences in fatigability outcomes were examined using analysis of variance. Results: SBC with persistent CRF had lower endurance (P = .003, ηp 2 = 0.205) and reported greater perceived exertion (P &lt; .001, ηp 2 = 0.284) during the STSF task, and demonstrated lower postexertional force (P = .035, ηp 2 = 0.109), power (P = .001, ηp 2 = 0.242), and slower STST (P = .001, ηp 2 = 0.258) compared with SBC without CRF. Conclusions: SBC with persistent CRF have increased fatigability compared with those without CRF. Our findings suggest that exercise recommendations for women with persistent CRF after breast cancer treatment should include activities that increase lower limb muscle force and power, such as heavy resistance or explosive-type strength training.

Validation of Smartphone Accelerometry for the Evaluation of Sit-To-Stand Performance and Lower-Extremity Function in Older Adults.

This study tested the concurrent and construct validity of smartphone accelerometry measurement of sit-to-stand (STS) performance in individuals aged 65-89 years. Normal and fast STS times were recorded by smartphone accelerometer, force plate, and video motion systems concurrently, and isokinetic knee extension power and STS whole-body power were obtained. Normal and fast speed STS times from a smartphone accelerometer agreed closely with force plate and motion system methods (mean difference = 0.04s). Normal and fast STS times were inversely related to isokinetic knee extension power (r = -.93, p < .001 and r = -.82, p < .001, respectively) and STS whole-body power (r = -.76, p < .001 and r = -.70, p < .001, respectively). The STS time obtained from a smartphone accelerometer was equivalent to the established, precise measures of STS time and was related to lower-extremity power, making it a potentially useful metric of lower-extremity function.

Rate of Force Development Is Related to Maximal Force and Sit-to-Stand Performance in Men With Stages 3b and 4 Chronic Kidney Disease.

Introduction:The primary aims of the present study were to assess the relationships of early (0–50 ms) and late (100–200 ms) knee extensor rate of force development (RFD) with maximal voluntary force (MVF) and sit-to-stand (STS) performance in participants with chronic kidney disease (CKD) not requiring dialysis.Methods:Thirteen men with CKD (eGFR = 35.17 ±.5 ml/min per 1.73 m2, age = 70.56 ±.4 years) and 12 non-CKD men (REF) (eGFR = 80.31 ± 4.8 ml/min per 1.73 m2, age = 70.22 ±.9 years) performed maximal voluntary isometric contractions to determine MVF and RFD of the knee extensors. RFD was measured at time intervals 0–50 ms (RFD0–50) and 100–200 ms (RFD100–200). STS was measured as the time to complete five repetitions. Measures of rectus femoris grayscale (RF GSL) and muscle thickness (RF MT) were obtained via ultrasonography in the CKD group only. Standardized mean differences (SMD) were used to examine differences between groups. Bivariate relationships were assessed by Pearson’s product moment correlation.Results:Knee extensor MVF adjusted for body weight (CKD=17.14 ±.1 N·kg0.67, REF=21.55 ±.3 N·kg0.67, SMD = 0.79) and STS time (CKD = 15.93 ±.4 s, REF = 12.23 ±.7 s, SMD = 1.03) were lower in the CKD group than the REF group. Absolute RFD100–200 was significantly directly related to adjusted MVF in CKD (r = 0.56, p = 0.049) and REF (r = 0.70, p = 0.012), respectively. STS time was significantly inversely related to absolute (r = −0.75, p = 0.008) and relative RFD0–50 (r = −0.65, p = 0.030) in CKD but not REF (r = 0.08, p = 0.797; r = 0.004, p = 0.991). Significant inverse relationships between RF GSL adjusted for adipose tissue thickness and absolute RFD100–200 (r =−0.59, p = 0.042) in CKD were observed.Conclusion:The results of the current study highlight the declines in strength and physical function that occur in older men with CKD stages 3b and 4 not requiring dialysis. Moreover, early RFD was associated with STS time in CKD while late RFD was associated MVF in both CKD and REF.Clinical Trial Registration:ClinicalTrials.gov, identifier: NCT03160326 and NCT02277236.

Sit-to-stand muscle power test: Comparison between estimated and force plate-derived mechanical power and their association with physical function in older adults.

This study aimed i) to assess the assumptions made in the sit-to-stand (STS) muscle power test [body mass accelerated during the ascending phase (90% of total body mass), leg length (50% of total body height) and concentric phase (50% of total STS time)], ii) to compare force plate-derived (FPD) STS power values with those derived from the STS muscle power test; and iii) to analyze the relationships of both measurements with physical function. Fifty community-dwelling older adults (71.3±4.4years) participated in the present investigation. FPD STS power was calculated as the product of measured force (force platform) and velocity [difference between leg length (DXA scan) and chair height, divided by time (obtained from FPD data and video analysis)], and compared to estimated STS power using the STS muscle power test. Physical function was assessed by the timed-up-and-go (TUG) velocity, habitual gait speed (HGS) and maximal gait speed (MGS). Paired t-tests, Bland-Altman plots and regressions analyses were conducted. Body mass accelerated during the STS phase was 85.1±3.8% (p<0.05; compared to assumed 90%), leg length was 50.7±1.3% of body height (p<0.05; compared to 50%), and measured concentric time was 50.3±4.6% of one STS repetition (p>0.05; compared to assumed 50%). There were no significant differences between FPD and estimated STS power values (mean difference [95% CI]=6.4W [-68.5 to 81.6W]; p=0.251). Both FPD and estimated relative (i.e. normalized to body mass) STS power were significantly related to each other (r=0.95 and ICC=0.95; p<0.05) and to MGS and TUG velocity after adjusting for age and sex (p<0.05). Estimated STS power was not different from FPD STS power and both measures were strongly related to each other and to maximal physical performance.

Sit-to-Stand Kinetics and Correlates of Performance in Young and Older Males

PurposeTo compare sit-to-stand (STS) kinetics in young (YM) and older (OM) males and determine correlates of STS performance. MethodsYM (n = 15, age = 20.7 ± 2.2 yrs) and OM (n = 15, age = 71.6 ± 3.9 yrs) performed a single STS task as quickly as possible on a force plate and the vertical ground reaction force (VGRF) signal was analyzed. Peak VGRF, as well as peak (100 ms rolling average), early (minimum VGRF to 50% peak VGRF), late (50% peak VGRF to peak VGRF), and overall (minimum VGRF to peak VGRF) rate of force development (RFD) were calculated. Power (absolute and relative) and velocity parameters as well as rate of electromyography rise (RER) were also obtained. ResultsSTS time, average power, early RFD, and lower limb lean mass were similar between groups (p > 0.05). All other power, velocity, RFD, and RER measures were lower in OM (p < 0.05; d = 0.41-2.19). Peak VGRF and all RFD measures, except late RFD, were strongly correlated with STS performance in OM, while peak VGRF and peak RFD were only moderately correlated with performance in YM. ConclusionsMost kinetic variables, except absolute average power, were diminished in OM, and there was a preferential decrease in late RFD compared to early RFD. Peak VGRF and RFD exhibited stronger correlations with STS time and power in OM compared to YM, and early RFD appears to be more influential for STS performance than late RFD. These findings may be useful for practitioners/clinicians involved in designing interventions aimed at optimizing STS performance in older adults.

Correlation between lower limb muscle asymmetry during the sit-to-stand task and spatiotemporal gait asymmetry in subjects with stroke.

The purpose of this study was to investigate the relationship between the both lower limb muscle asymmetry during sit-to-stand (STS) and spatiotemporal gait asymmetry in subjects with stroke. Twenty-nine patients were included in this study, lower limb muscle (rectus femoris, tibialis anterior, gastrocnemius) asymmetry during STS, five times sit-to-stand (FTSTS) and spatiotemporal (speed, step length, step time, swing time, stance time, single support time) gait asymmetry were measured. According to the results of the measurement, significant positive correlations between gastrocnemius and rectus femoris asymmetry during STS and step length asymmetry. Furthermore, significant positive correlations between rectus femoris asymmetry during STS and step time asymmetry. In addition, significant negative correlations between the FTSTS and gait speed. This study’s results suggested that necessary to apply exercise that the gastrocnemius and rectus femoris symmetry during STS for improving step length and step time symmetry of gait, and necessary to apply exercise that increase STS speed for gait speed.

The sit-to-stand muscle power test: An easy, inexpensive and portable procedure to assess muscle power in older people.

Skeletal muscle power has been demonstrated to be a stronger predictor of functional limitations than any other physical capability. However, no validated alternatives exist to the usually expensive instruments and/or time-consuming methods to evaluate muscle power in older populations. Our aim was to validate an easily applicable procedure to assess muscle power in large cohort studies and the clinical setting and to assess its association with other age-related outcomes. Forty community dwelling older adults (70-87 years) and 1804 older subjects (67-101 years) participating in the Toledo Study for Healthy Aging were included in this investigation. Sit-to-stand (STS) velocity and muscle power were calculated using the subject's body mass and height, chair height and the time needed to complete five STS repetitions, and compared with those obtained in the leg press exercise using a linear position transducer. In addition, STS performance, physical (gait speed) and cognitive function, sarcopenia (skeletal muscle index (SMI)) and health-related quality of life (HRQoL) were recorded to assess the association with the STS muscle power values. No significant differences were found between STS velocity and power values and those obtained from the leg press force-velocity measurements (mean difference ± 95% CI = 0.02 ± 0.05 m·s-1 and 6.9 ± 29.8 W, respectively) (both p > 0.05). STS muscle power was strongly associated with maximal muscle power registered in the leg press exercise (r = 0.72; p < 0.001). In addition, cognitive function and SMI, and physical function, were better associated with absolute and relative STS muscle power, respectively, than STS time values after adjusting by different covariates. In contrast, STS time was slightly more associated with HRQoL than STS muscle power measures. The STS muscle power test proved to be a valid, and in general, a more clinically relevant tool to assess functional trajectory in older people compared to traditional STS time values. The low time, space and material requirements of the STS muscle power test, make this test an excellent choice for its application in large cohort studies and the clinical setting.

The PhyStat 7

This observational study was undertaken to describe a battery of 7 measurements of physical status, the PhyStat 7, and to determine the time requirements and clinimetric properties of the battery. Ten men and 10 women (aged 60-79 years) were examined during 2 sessions 10 to 14 days apart. A younger comparison group of 10 men and 10 women (aged 20-29 years) was also examined. During the first session, each of 2 testers independently obtained 7 measurements from all participants: (1) body mass index (BMI); (2) tragus-to-wall (TTW) distance; (3) unipedal stance time (UST); (4) 5-repetition sit-to-stand (STS) time; (5) grip strength; (6) gait speed; and (7) 2-Minute Walk Test (2MWT) distance. During the second session, 1 of the 2 testers repeated the 7 measurements with the older participants. The PhyStat 7 took an average of 12 minutes to administer. For individual items of the PhyStat 7, intraclass correlation coefficients (ICCs [model 3,1]) describing intertester reliability ranged from 0.712 to 0.997 and ICCs describing test-retest reliability ranged from 0.676 to 0.998. For a total PhyStat 7 score derived by adding z-transformed individual items, the ICCs for intertester reliability and test-retest reliability were 0.939 and 0.893, respectably. Content validity was supported by loadings on 2 factors—physical structure (BMI and TTW distance) and physical performance (UST, STS time, grip strength, gait speed, and 2MWT). Known-groups validity was demonstrated by significant differences between the older and younger groups in all items except BMI and gait speed.

Relationship of Sit-to-Stand Lower-Body Power With Functional Fitness Measures Among Older Adults With and Without Sarcopenia.

When evaluating health in older adults, batteries of tests are typically utilized to assess functional fitness. Unfortunately, physician's visits are time-sensitive, and it may be important to develop faster methods to assess functional fitness that can be utilized in professional or clinical settings. Therefore, the purpose of this investigation was to examine the relationship of sit-to-stand (STS) power generated through the STS task with previously established measures of functional fitness, specifically strength, endurance, speed, agility, and flexibility in older adults with and without sarcopenia. This study consisted of 57 community-dwelling older adults (n = 16 males; n = 41 females). Functional fitness was assessed using the Short Physical Performance Battery (SPPB), Senior Fitness Test, handgrip, gait speed (habitual and maximal), balance, and STS power generated via the Tendo Weightlifting Analyzer. On the basis of data distribution, second-degree polynomial (quadratic) curvilinear models (lines of best fit) were applied for the relationships of 5-time STS time with average and peak power. Zero-order correlations were evaluated between STS power and all other functional fitness measures. Older adults with sarcopenia were also identified (n = 15), and relationships were reevaluated within this subset. STS power (average and peak) was significantly (P ≤ .01) correlated with physical performance measured via previously established assessments. For average power, this was observed during the senior fitness test (6-minute walk [r = 0.39], 8-ft up-and-go [r = -0.46], arm curl [r = 0.46], and chair stand [r = 0.55]), SPPB (5-time STS time [r = -0.63] and 8-ft walk [r = -0.32]), and other independent functional fitness measures (grip strength [r = 0.65] and maximal gait speed [r = -0.31]). Similar results were observed for peak power during the senior fitness test (6-minute walk [r = 0.39], 8-ft up-and-go [r = -0.46], arm curl [r = 0.45], chair stand [r = 0.52], and sit-and-reach [r = -0.27]), SPPB (5-time STS time [r = -0.60] and 8-ft walk [r = -0.33]), and other independent functional fitness measures (grip strength [r = 0.70] and maximal gait speed [r = -0.32]). Within the sarcopenic subset, for average and peak power, respectively, significant relationships were still retained for handgrip strength (r = 0.57 and r = 0.57), 6-minute walk (r = 0.55 and r = 0.61), chair stand (r = 0.76 and r = 0.81), and 5-time STS time (r = -0.76 and r = -0.80) tests. STS power generated via the STS task significantly relates to commonly administered functional fitness measures. These relationships also appear to exist when evaluating these relationships in older adults with sarcopenia. STS power may be utilized as an independent measure of functional fitness that is feasible to incorporate in clinical settings where time and space are often limiting factors.

Anatomical cross-sectional area of the quadriceps femoris and sit-to-stand test score in middle-aged and elderly population: development of a predictive equation

BackgroundAlthough the sit-to-stand (STS) test score has been shown to relate to the strength and size of the quadriceps femoris (QF) for elderly population, it is unknown whether this relationship is influenced by a posture (i.e., the trunk being allowed to stoop or not) during the STS test. The present study investigated the relationship between STS test score and QF anatomical cross-sectional area (ACSA) in the middle-aged and elderly population with regard to the difference in the posture during STS test, and aimed to develop an accurate predicting equation of the QF ACSA from the STS test score.Methods105 males (40–81 years) and 113 females (41–79 years) participated in the present study, then the subjects were divided at random as validation and cross-validation groups. Mid-thigh QF ACSA was determined by magnetic resonance imaging. Subjects performed a 10-repeated STS as fast as possible in two conditions: (1) with the trunk being allowed to stoop during the sitting phases, and (2) kept upright throughout the test. A power index of the STS test score was calculated based on an equation obtained in a previous study using the time taken for each test condition, the thigh and shank lengths, and body mass. In the validation group (n = 109), a stepwise multiple linear regression analysis was performed to create a predictive model of the ACSA with sex, age, the STS time, and power for both conditions as independent variables. The formulated predictive equation was examined in the cross-validation group (n = 109).ResultsIn the validation group, a stepwise regression analysis revealed that STS power with upright trunk condition, sex, and age but not with the stooping condition, were selected as variables to predict QF ACSA (R2 = 0.64, P < 0.001). There was no systematic error for the relationship between predicted and measured values in the cross-validation group.ConclusionsThese results indicate that STS test score with upright trunk condition is one of the indices of QF muscle size of the middle-aged and elderly population. The estimated predicting equation should be useful in clinical and practical settings for the health promotion.

Effect of light and vigorous physical activity on balance and gait of older adults

This study aims to quantitatively assess the effects of vigorous and light physical activity (VPA, LPA) on static balance, gait and sit-to-stand (STS) tasks in a cohort of healthy older adults.To this end, 34 individuals of age >65 years were divided into two groups (n=17 each) who underwent 36 sessions (3×12 weeks) of PA characterized by different levels of intensity, assessed through continuous heart rate monitoring during the training session. Their balance and mobility were objectively evaluated on the basis of postural sway and time of STS measurements performed using a force platform. The main spatiotemporal parameters of gait (i.e. speed, stride and gait cycle duration, stance, swing and double support phase duration) were also acquired using a wearable inertial measurement unit.The results show that most gait parameters and STS time significantly improve in the VPA group but not in the LPA one. For the latter group a reduction only of swing phase duration was detected. PA also induced a generalized reduction of postural sway in both groups in the case of absence of visual input.These findings suggest that PA programs characterized by superior levels of intensity might be more suitable in generally improving static and dynamic daily motor tasks, while in terms of static balance acceptable results can be achieved even when only light activity is performed.

Sit-To-Stand (STS) timing among older adults in their homes: Two measurement approaches

Sit-to-stand (STS) times required by older adults exiting from their beds at home were compared simultaneously using under mattress pressure sensor technology and video analysis. Six older adults consented to participate in the study and had under mattress pressure technology installed in their homes. Participants were visited monthly over a period of 2-10 months by a researcher who asked them to perform three bed exits which were videotaped. The pressure sensor technology calculated a portion of STS time based on changes in pressure between the end of stable sitting on the edge of the bed and pressure leaving the bed. The video analysis approach calculated this corresponding initial phase of the same STS transfer by determining the difference between the first forward movement from the quiet sitting position and the initiation of vertical rise. The remaining period of vertical rise into a complete standing position was calculated using video analysis but not pressure sensor technology. A Spearman’s rank order correlation analysis revealed that there was a moderate, positive correlation between the video and pressure-sensor measures of the initial phase of STS which was statistically significant (r s =0.50, n=97, p<0.001). Wilcoxon signed-rank tests indicated that pressure sensor times were longer (Z=-7.91, p<0.000) and more variable than video times (Z=-3.14, p=0.002). Analysis of video data revealed that this initial phase of STS represented between 15 to 81% of the total STS time among the 97 sampled STS in this study. Results highlight how the home environment presents a number of conditions affecting differences in STS values obtained by each of these measurement approaches.

Sit-to-Stand Measurement for In-Home Monitoring Using Voxel Analysis

We present algorithms to segment the activities of sitting and standing, and identify the regions of sit-to-stand (STS) transitions in a given image sequence. As a means of fall risk assessment, we propose methods to measure STS time using the 3-D modeling of a human body in voxel space as well as ellipse fitting algorithms and image features to capture orientation of the body. The proposed algorithms were tested on ten older adults with ages ranging from 83 to 97. Two techniques in combination yielded the best results, namely the voxel height in conjunction with the ellipse fit. Accurate STS time was computed on various STSs and verified using a marker-based motion capture system. This application can be used as part of a continuous video monitoring system in the homes of older adults and can provide valuable information to help detect fall risk and enable early interventions.

Association of serum uric acid level with muscle strength and cognitive function among Chinese aged 50–74 years

Previous studies have shown that uric acid (UA) has strong anti-oxidant properties, and that high circulating levels of UA are prospectively associated with improved muscle function and cognitive performances in elderly Caucasians. We carried out a replication study in elderly Chinese using cross-sectional design. Data from 2006 individuals aged 50-74 years who participated in a population-based cross-sectional survey in Qingdao, China, were analyzed. Hand grip strength was measured in kilograms by using an electronic dynamometer. The sit-to-stand (STS) test time was used to represent lower limb strength. The Mini-Mental State Examination (MMSE) was used to estimate the participants' cognitive function. Lifestyle, comorbidities and laboratory measures were considered as potential confounders. Multiple linear regression models and binary logistic regression were fitted to find the association of UA with strength measures and cognitive performances. Participants were grouped according to UA tertiles (<257.75 mmol/L, ≥ 257.75 and ≤ 359.00 mmol/L, >359.00 mmol/L). Hand grip strength significantly increased across UA tertiles (26.4 ± 8.5 kg; 30.1 ± 10.5 kg; 35.0 ± 11.4 kg; P<0.001), and prevalence of cognitive disorder declined across UA tertiles (7.9%, 4.9%, 3.1%; P=0.012). After adjusting for potential confounders, high UA level remained significantly associated with high grip strength (P=0.023) and decreased risk of cognitive disorder with an OR of 1.002 (95% CI 1.000-1.004; P=0.022). However, UA level was not significantly associated with STS time (P=0.780). Our findings suggested that notwithstanding the associated increased risk of cardiovascular disease, UA might play a protective role in aging-associated decline in muscle strength and cognitive function.

Five-repetition sit-to-stand test performance by community-dwelling adults: A preliminary investigation of times, determinants, and relationship with self-reported physical performance

The 5-repetition sit-to-stand (STS) test is a widely used, but insufficiently evaluated, test for lower limb strength. We therefore described STS test times for a sample of community-dwelling adults, examined the association of age, gender, height, weight, and body mass index (BMI) with STS time, and determined the relationship of STS time with self-reported physical functioning. Ninety-four community dwelling adults participated. Repeated measures of STS time were reliable (intraclass correlation coefficient = 0.957). The mean STS time for all 94 subjects was 7.6 seconds. Age, weight, and BMI were (r = 0.281-0.528), but gender and height were not (r = -0.074 - 0.007), correlated significantly with STS time. Regression analysis showed that age and BMI explained 43.7 percent of the variance in STS time. The correlation between STS time and physical functioning (r = -0.474) was significant (p < 0.001). Regression analysis showed that age and BMI added slightly to the explanation of variance in physical functioning provided by STS time. In conclusion, this study provides STS times that might be useful for interpreting performance of adults screened with the test. Such performance should be considered in light of age and BMI. The relationship of STS time with physical functioning provides evidence of the validity of the measure.

Reliability of the sit-to-stand test over dispersed test sessions

This study focused on the reliability, differences, and error of sit-to-stand (STS) test measurements obtained during 3 sessions separated by 6 weeks. Twenty-one community-dwelling elders (65-85 years) participated. The mean times required to complete five STS repetitions at each test session were 13.2, 12.0, and 10.9 seconds. The times were reliable (intraclass correlation coefficient = 0.82) but were significantly different (F = 6.889, p = 0.003) and demonstrated a linear trend over sessions (F = 10.157, p = 0.005). The technical error of the measurement for the times ranged from 1.7 to 2.8 seconds. Although the intraclass correlation coefficient showed the STS measurement to possess good reliability, the significant difference and trend over time suggests that subjects may experience some test familiarization with repeated performance. Given this possibility and the technical error of the measurement, clinicians should be cautious in equating small decreases in STS time to real improvement.