Can sit-to-stand muscle power explain the ability to perform functional tasks in adults with severe obesity?

Test-Retest Reliability and Convergent Validity of Piezoelectric Force Plate Measures of Single-Leg Sit-to-Stand Performance in Trained Adults

ABSTRACT

Makaracı, Y, Nas, K, Ruiz-Cárdenas, JD, Gündüz, K, Aydemir, M, and Orange, ST. Test-retest reliability and convergent validity of piezoelectric force plate measures of single-leg sit-to-stand performance in trained adults. J Strength Cond Res 37(12): 2373-2380, 2023-The single-leg sit-to-stand (STS) test has emerged as a promising method of assessing lower-limb functional strength and asymmetry. However, the reliability of its performance parameters on a force plate has not been explored. This study examined the test-retest reliability and convergent validity of the single-leg STS test performed on a piezoelectric-based force plate in trained subjects. Thirty trained male adults (age: 21.4 ± 1.7 years) performed 3 separate single-leg STS days of testing to assess both intraday and interday reliability. Performance parameters included STS time, ground reaction force (GRF), and center of pressure (CoP) sway velocity. The relationship between single-leg STS parameters and unilateral countermovement jump (CMJ) variables was assessed for convergent validity. Intraclass correlation coefficient (ICC) and coefficient of variation (CV) were calculated for reliability analyses, and convergent validity was assessed with Spearman's correlation coefficient (ρ). In the dominant leg, single-leg performance parameters showed moderate-to-excellent intraday reliability (ICC = 0.65-0.90, CV = 4.3-11.2%) and moderate interday reliability (ICC = 0.54-0.74, CV = 5.8-13.5%). In the nondominant leg, all single-leg STS performance parameters showed good intraday (ICC = 0.79-0.86, CV = 3.8-9.8%) and interday reliability (ICC = 0.75-0.82, CV = 4.6-9.7%). STS times in the dominant and nondominant legs were inversely related to unilateral CMJ velocity (ρ = -0.47 and -0.38, respectively). CoP sway velocity in the nondominant leg showed positive correlations with unilateral CMJ power and velocity (ρ = 0.38 and 0.54, respectively). In conclusion, the force plate-based single-leg STS test provides reliable measures of STS time, GRF, and CoP sway velocity in trained adults and could be used to assess lower-limb function and asymmetry.

Epidemiological, mechanistic, and practical bases for assessment of cardiorespiratory fitness and muscle status in adults in healthcare settings

Given their importance in predicting clinical outcomes, cardiorespiratory fitness (CRF) and muscle status can be considered new vital signs. However, they are not routinely evaluated in healthcare settings. Here, we present a comprehensive review of the epidemiological, mechanistic, and practical bases of the evaluation of CRF and muscle status in adults in primary healthcare settings. We highlight the importance of CRF and muscle status as predictors of morbidity and mortality, focusing on their association with cardiovascular and metabolic outcomes. Notably, adults in the best quartile of CRF and muscle status have as low as one-fourth the risk of developing some of the most common chronic metabolic and cardiovascular diseases than those in the poorest quartile. The physiological mechanisms that underlie these epidemiological associations are addressed. These mechanisms include the fact that both CRF and muscle status reflect an integrative response to the body function. Indeed, muscle plays an active role in the development of many diseases by regulating the body's metabolic rate and releasing myokines, which modulate metabolic and cardiovascular functions. We also go over the most relevant techniques for assessing peak oxygen uptake as a surrogate of CRF and muscle strength, mass, and quality as surrogates of muscle status in adults. Finally, a clinical case of a middle-aged adult is discussed to integrate and summarize the practical aspects of the information presented throughout. Their clinical importance, the ease with which we can assess CRF and muscle status using affordable techniques, and the availability of reference values, justify their routine evaluation in adults across primary healthcare settings.

Reproducibility and safety of the 30" sit to stand test in individuals with obesity and cardiovascular risk factors

BACKGROUND

The 30″ sit to stand test is a submaximal exercise test that assesses functional capacity and it has been validated for various pathologies. Although it has been used in individuals with obesity, its reproducibility in this population has not yet been determined. The main objective of this study was to determine the reproducibility and safety of the 30″ sit to stand test in individuals with overweight or obesity and with cardiovascular risk factors.

METHODS

A cross-sectional study was performed. Individuals with obesity or overweight who also presented cardiovascular risk factors were evaluated with the 30″ sit to stand test. The reproducibility and safety of the 30" sit to stand test were determined, as well as its association with other functional tests and anthropometric characteristics.

RESULTS

59 individuals (27 men, 32 women) with obesity or overweight and cardiovascular risk factors, aged 57.93 (9.62) years, were included in the study. The 30″ sit to stand test showed good overall reproducibility (0.907 ICC) and significant correlation with the 6-minute walk test, handgrip strength test, body fat percentage and waist - height index, with a similar hemodynamic response to the 6-minute walk test.

CONCLUSION

The 30" sit to stand test is a highly reproducible and safe test for individuals with obesity and cardiovascular risk factors, with a significant correlation to anthropometric characteristics and other functional tests regularly used for the evaluation of individuals with obesity.

Effects of pre-surgical aerobic dance-based exercise on lower extremity in people with morbid obesity awaiting bariatric surgery: Randomized controlled study

To investigate what are the effects of pre-surgical aerobic dance-based exercise programme (PSADBE) and physical activity counselling (PAC) programme on lower extremity functions after surgery in people with morbid obesity awaiting bariatric surgery (PMOABS). This study was a single-blind, randomized controlled study. Groups were divided into Group I (PSADBE and PAC) and Group II (PAC). Both groups received PAC, Group I completed the PSADBE programme accompanied by music for 60 min/2 days/8 weeks. Thirty-four PMOABS were included in the study. The 6-Minute Walking Test, as primary outcomes, and The Stair Climbing Up-Down Test for evaluating functional capacity, Biodex Isokinetic Test and Exercise System® for evaluating muscle strength were used. Besides, muscle endurance, physical activity (PA) level, fatigue and quality of life (QoL) were also assessed. All measurements were repeated three times; pre-treatment, post-treatment and the fifth-month post-surgery. After 8 weeks, significant changes were found in functional capacity, muscle strength and endurance, PA level, fatigue and QoL in both groups (p < .05). Comparing the groups, the changes in functional capacity, muscle strength and endurance, PA and fatigue scores after treatment and the fifth-month post-surgery were statistically superior in Group I (p < .05). Adding an 8-week PSADBE programme to PAC is an effective treatment option for improving postoperative functional capacity, muscle strength and endurance, PA level and fatigue in PMOABS.

Development of a functional assessment task in metastatic breast cancer patients: the 30-second lie-to-sit test

PURPOSE

To develop a physical function test based on lie-to-sit transition and to study its feasibility in patients suffering from metastatic breast cancer (MBC).

MATERIALS AND METHODS

This cross-sectional study recruited 90 women diagnosed with MBC. Patients were asked to transfer from lying to sitting position as fast as possible during 30 s, performing the 30-second lie-to-sit test (30-LTS). Heart rate (HR), rate of perceived exertion (RPE) and number of repetitions were measured. An assessment included the 30-second sit-to-stand test (30-STS), handgrip strength, Upper Limb Functional Index (ULFI) and Lower Limb Functional Index (LLFI). Pearson correlation was calculated between 30-LTS and independent outcomes. A linear regression model explaining the 30-LTS results was further constructed with variables that had a significant correlation.

RESULTS

About 72 patients were measured, of which 65 were able to perform 30-LTS. Subjects performed 8.13 repetitions on average, with a mean RPE of 4.78 (0-10), reaching 63.08% of maximal HR. 30-LTS was significantly correlated with 30-STS (r = 0.567), handgrip (p = 0.26) and LLFI (r = 0.348). The regression model was significant (F = 4.742; p = 0.00), and these variables explained 32% of the variance of the 30-LTS.

CONCLUSION

The 30-LTS showed to be a feasible functional and submaximal test in a sample of MBC. IMPLICATIONS FOR REHABILITATIONThe 30-second lie-to-sit (30-LTS) developed does not require the patient to acquire a standing position and therefore it is an alternative to other more biomechanically demanding tests such as a 30 second sit-to-stand test or Timed up-and-go.30-LTS involves both a functional and energy system assessment tool that can be implemented by allied health professionals in oncology rehabilitation to individualize exercise prescription, as well as for functional screening purposes.The present study adds value to current research focused on individualizing exercise prescription in the oncology field and provides reference values of function in metastatic breast cancer patients.

Comparison of the effects of velocity-based vs. traditional resistance training methods on adaptations in strength, power, and sprint speed: A systematic review, meta-analysis, and quality of evidence appraisal

We estimated the effectiveness of using velocity feedback to regulate resistance training load on changes in muscle strength, power, and linear sprint speed in apparently healthy participants. Academic and grey literature databases were systematically searched to identify randomised trials that compared a velocity-based training intervention to a 'traditional' resistance training intervention that did not use velocity feedback. Standardised mean differences (SMDs) were pooled using a random effects model. Risk of bias was assessed with the Risk of Bias 2 tool and the quality of evidence was evaluated using the GRADE approach. Four trials met the eligibility criteria, comprising 27 effect estimates and 88 participants. The main analyses showed trivial differences and imprecise interval estimates for effects on muscle strength (SMD 0.06, 95% CI -0.51-0.63; I² = 42.9%; 10 effects from 4 studies; low-quality evidence), power (SMD 0.11, 95% CI -0.28-0.49; I² = 13.5%; 10 effects from 3 studies; low-quality evidence), and sprint speed (SMD -0.10, 95% CI -0.72-0.53; I² = 30.0%; 7 effects from 2 studies; very low-quality evidence). The results were robust to various sensitivity analyses. In conclusion, there is currently no evidence that VBT and traditional resistance training methods lead to different alterations in muscle strength, power, or linear sprint speed.

Clinically Important Reductions in Physical Function and Quality of Life in Adults with Tumor Prostheses in the Hip and Knee: A Cross-sectional Study

BACKGROUND

Patients with a bone sarcoma who undergo limb-sparing surgery and reconstruction with a tumor prosthesis in the lower extremity have been shown to have reduced self-reported physical function and quality of life (QoL). To provide patients facing these operations with better expectations of future physical function and to better evaluate and improve upon postoperative interventions, data from objectively measured physical function have been suggested.

QUESTIONS/PURPOSES

We sought to explore different aspects of physical function, using the International Classification of Functioning, Disability, and Health (ICF) as a framework, by asking: (1) What are the differences between patients 2 to 12 years after a bone resection and reconstruction surgery of the hip and knee following resection of a bone sarcoma or giant cell tumor of bone and age-matched controls without walking limitations in ICF body functions (ROM, muscle strength, pain), ICF activity and participation (walking, getting up from a chair, daily tasks), and QoL? (2) Within the patient group, do ICF body functions and ICF activity and participation outcome scores correlate with QoL?

METHODS

Between 2006 and 2016, we treated 72 patients for bone sarcoma or giant cell tumor of bone resulting in bone resection and reconstruction with a tumor prosthesis of the hip or knee. At the timepoint for inclusion, 47 patients were alive. Of those, 6% (3 of 47) had undergone amputation in the lower limb and were excluded. A further 32% (14 of 44) were excluded because of being younger than 18 years of age, pregnant, having long transportation, palliative care, or declining participation, leaving 68% (30 of 44) for analysis. Thus, 30 patients and 30 controls with a mean age of 51 ± 18 years and 52 ± 17 years, respectively, were included in this cross-sectional study. Included patients had been treated with either a proximal femoral (40% [12 of 30]), distal femoral (47% [14 of 30]), or proximal tibia (13% [4 of 30]) reconstruction. The patients were assessed 2 to 12 years (mean 7 ± 3 years) after the resection-reconstruction. The controls were matched on gender and age (± 4 years) and included if they considered their walking capacity to be normal and had no pain in the lower extremity. Included outcome measures were: passive ROM of hip flexion, extension, and abduction and knee flexion and extension; isometric muscle strength of knee flexion, knee extension and hip abduction using a hand-held dynamometer; pain intensity (numeric rating scale; NRS) and distribution (pain drawing); the 6-minute walk test (6MWT); the 30-second chair-stand test (CST); the Toronto Extremity Salvage Score (TESS), and the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30). The TESS and the EORTC QLQ-C30 were normalized to 0 to 100 points. Higher scoring represents better status for TESS and EORTC global health and physical functioning scales. Minimum clinically important difference for muscle strength is 20% to 25%, NRS 2 points, 6MWT 14 to 31 meters, CST 2 repetitions, TESS 12 to 15 points, and EORTC QLQ-C30 5 to 20 points.

RESULTS

Compared with controls, the patients had less knee extension and hip abduction strength in both the surgical and nonsurgical limbs and regardless of reconstruction site. Mean knee extension strength in patients versus controls were: surgical limb 0.9 ± 0.5 Nm/kg versus 2.1 ± 0.6 Nm/kg (mean difference -1.3 Nm/kg [95% CI -1.5 to -1.0]; p < 0.001) and nonsurgical limb 1.7 ± 0.6 Nm/kg versus 2.2 ± 0.6 Nm/kg (mean difference -0.5 Nm/kg [95% CI -0.8 to -0.2]; p = 0.003). Mean hip abduction strength in patients versus controls were: surgical limb 1.1 ± 0.4 Nm/kg versus 1.9 ± 0.5 Nm/kg (mean difference -0.7 Nm/kg [95% CI -1.0 to -0.5]; p < 0.001) and nonsurgical limb 1.5 ± 0.4 Nm/kg versus 1.9 ± 0.5 Nm/kg (-0.4 Nm/kg [95% CI -0.6 to -0.2]; p = 0.001). Mean hip flexion ROM in patients with proximal femoral reconstructions was 113° ± 18° compared with controls 130° ± 11° (mean difference -17°; p = 0.006). Mean knee flexion ROM in patients with distal femoral reconstructions was 113° ± 29° compared with patients in the control group 146° ± 9° (mean difference -34°; p = 0.002). Eighty-seven percent (26 of 30) of the patients reported pain, predominantly in the knee, anterior thigh, and gluteal area. The patients showed poorer walking and chair-stand capacity and had lower TESS scores than patients in the control group. Mean 6MWT was 499 ± 100 meters versus 607 ± 68 meters (mean difference -108 meters; p < 0.001), mean CST was 12 ± 5 repetitions versus 18 ± 5 repetitions (mean difference -7 repetitions; p < 0.001), and median (interquartile range) TESS score was 78 (21) points versus 100 (10) points (p < 0.001) in patients and controls, respectively. Higher pain scores correlated to lower physical functioning of the EORTC QLQ-C30 (Rho -0.40 to -0.54; all p values < 0.05). Less muscle strength in knee extension, knee flexion, and hip abduction correlated to lower physical functioning of the EORTC QLQ-C30 (Rho 0.40 to 0.51; all p values < 0.05).

CONCLUSION

This patient group demonstrated clinically important muscle weaknesses not only in resected muscles but also in the contralateral limb. Many patients reported pain, and they showed reductions in walking and chair-stand capacity comparable to elderly people. The results are relevant for information before surgery, and assessments of objective physical function are advisable in postoperative monitoring. Prospective studies evaluating the course of physical function and which include assessments of objectively measured physical function are warranted. Studies following this patient group with repetitive measures over about 5 years could provide information about the course of physical function, enable comparisons with population norms, and lead to better-designed, targeted, and timely postoperative interventions.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The effects of core stabilization exercise program in obese people awaiting bariatric surgery: A randomized controlled study

OBJECTIVE

The aim of this study was the effects of the core stabilization exercise program (CSEP) and physical activity counseling on functional capacity, physical fitness, physical activity, fatigue and quality of life (QoL) in obese people awaiting bariatric surgery.

METHODS

Twenty-one patients were divided into two groups: an exercise group (n = 10) and a control group (n = 11). Both groups received physical activity counseling, but the exercise group also performed an 8-week CSEP. Functional capacity, physical fitness, physical activity, fatigue and QoL were assessed at baseline and after 8 weeks.

RESULTS

After eight weeks, results showed significant improvements in all parameters except for body composition for the exercise group, comparing to the control group (effect size = 0.40-0.87, p < 0.05).

CONCLUSIONS

Implementing an 8-week adding CSEP to physical activity counseling provided significant improvements in functional capacity, physical fitness, physical activity, fatigue and QoL compared to physical activity counseling in obese people awaiting bariatric surgery.

Validity, reliability, and measurement error of a sit-to-stand power test in older adults: A pre-registered study

OBJECTIVES

Lower body power declines with age and is associated with decreased physical function in older adults. However, the majority of the tools available to measure power are expensive and require considerable space and expertise to operate. The purpose of this study was to assess the validity, reliability, and measurement error of a sit-to-stand power test (STSp) to assess lower body power.

METHODS

51 community-dwelling adults, 65 years or older, completed a power test using a pneumatic leg press (LP), the Short Physical Performance Battery (SPPB) that includes a test of balance, usual walking speed, and chair stand tests; Timed Up and Go (TUG) test at both usual and fast paces, and Patient-Reported Outcome Measures (PROMs). A two-week test-retest assessed the reliability in 36 participants. The study hypotheses and analysis were pre-registered prior to data collection and statistical analyses were blinded.

RESULTS

The mean age was 71.3 years, with 63% females, and an average SPPB score of 10.6 (median = 12). STSp peak power was strongly correlated with LP (r = 0.90, 95% CI (0.82, 0.94). As hypothesized, the STSp peak power showed similar or higher correlations with physical function tests relative to LP peak power: SPPB (0.41 vs. 0.29), chair stand test (-0.44 vs. -0.35), TUG test at usual pace (-0.37 vs. -0.29) and fast pace (-0.41 vs. -0.34) and balance (0.33 vs. 0.22), but not for mobility (0.34 vs. 0.38) and function (0.41 vs. 0.48) questionnaire. For discriminant validity, as hypothesized, males showed higher STSp peak power compared to females (Δ = 492 W, p < .001, Cohen's d = 2.0). Test-retest assessment yielded an intraclass correlation coefficient of 0.96 and a standard error of measurement of 70.4 W. No adverse events were reported or observed for both tests.

CONCLUSION

The STSp showed adequate validity and reliability in measuring lower body power in community-dwelling older adults. The test is quick, relatively inexpensive, safe, and portable and thus should be considered for use in aging research.

Resistance training leads to large improvements in strength and moderate improvements in physical function in adults who are overweight or obese: a systematic review

QUESTIONS

What are the effects of resistance training on muscle strength, physical function and muscle power in adults who are overweight or obese? Which factors moderate the effects?

DESIGN

Systematic review of randomised controlled trials, with random effects meta-analyses and meta-regressions.

PARTICIPANTS

Adults who are overweight or obese.

INTERVENTION

Resistance training lasting ≥ 4 weeks.

OUTCOME MEASURES

Muscle strength, muscle power and physical function.

RESULTS

Thirty trials with 1,416 participants met the eligibility criteria. Pooled analyses indicated that resistance training has a large beneficial effect on muscle strength (SMD 1.39, 95% CI 1.05 to 1.73, I² = 85%) and a moderate effect on physical function (SMD 0.67, 95% CI 0.25 to 1.08, I² = 71%) in adults who are overweight or obese. However, the effect of resistance training on muscle power was unclear (SMD 0.42, 95% CI -3.3 to 4.2, I² = 46%). The effect of resistance training on strength was greatest for the upper body (versus lower/whole body: β = 0.35, 95% CI 0.05 to 0.66) and in dynamic strength tests (versus isometric/isokinetic: β = 1.20, 95% CI 0.60 to 1.81), although trials judged to have good methodological quality reported statistically smaller effects (versus poor/fair quality: β = -1.21, 95% CI -2.35 to -0.07). Concomitant calorie restriction did not modify strength gains but reduced the effect of resistance training on physical function (β = -0.79, 95% CI -1.41 to -0.17). Small study effects were evident for strength outcomes (β = 5.9, p < 0.001).

CONCLUSIONS

Resistance training has a large positive effect on muscle strength and a moderate effect on physical function in adults who are overweight or obese. However, the effect of resistance training on muscle power is uncertain. In addition, concomitant calorie restriction may compromise the functional adaptations to resistance training.

REGISTRATION

PROSPERO CRD42019146394.

Determinants of Performance in the Timed Up-and-Go and Six-Minute Walk Tests in Young and Old Healthy Adults

The aim of this study was to assess associations between performance in the timed up-and-go (TUG) and six-minute walk distance (6MWD) with physiological characteristics in young and old healthy adults. Thereto, we determined TUG, 6MWD, normalised jump power, centre of pressure displacement during 1-leg standing, forced expiratory volume in 1 s, percentage of age-predicted maximal heart rate (HR%) and height in 419 healthy young (men: 23.5 ± 2.8 years, women: 23.2 ± 2.9 years) and old (men: 74.6 ± 3.2 years, women: 74.1 ± 3.2 years) adults. Normalised jump power explained 8% and 19% of TUG in young (p = 0.025) and older men (p < 0.001), respectively. When fat mass percentage and age were added to normalised jump power, 30% of TUG was explained in older men (R2adj = 0.30, p < 0.001 to 0.106). Appendicular lean muscle mass percentage (ALM%) and age were the best determinants of TUG for older women (R2adj = 0.16, p < 0.001 to 0.01). HR% explained 17-39% of 6MWD across all groups (R2adj = 0.17 to 39, p < 0.001). In conclusion, in men, jump power was a key determinant for TUG, while in old women only it was the ALM%. As HR% was the most important determinant of 6MWD, motivational bias needs to be considered in the interpretation of this test.

Validity of various portable devices to measure sit-to-stand velocity and power in older adults

BACKGROUND

Movement velocity and power in a single STS are related to functional performance in older adults. Identifying accessible tools that provide valid measures of STS velocity/power would allow practitioners to evaluate physical function in clinical settings where time, space and finances are limited.

RESEARCH QUESTION

Does a linear position transducer (LPT), iPhone application (App), and inertial measurement unit (IMU) obtain valid measurements of velocity and power during a single STS compared with 3D motion capture?

METHODS

Twenty-seven community-dwelling older adults aged ≥60 years completed a single STS test with mean velocity and power simultaneously measured with 3D motion capture, an LPT, IMU and App. Acceptable validity was established if the Pearson correlation coefficient (r) was very high (≥0.7) and bias as a standardised effect size (ES) was small (<0.6). The relationship between STS velocity/power and 30s chair STS performance was also evaluated.

RESULTS

Measures of STS velocity obtained by the LPT (r = 0.94, ES = -0.21) and App (r = 0.89, ES = -0.19) were very highly valid when compared to 3D motion capture, and were very strongly related to 30s STS performance (r ≥0.74). The LPT (r = 0.87, ES = 0.13) and App (r = 0.74, ES = -0.12) also showed very high correlations and negligible bias for measuring STS power. Data collected by the IMU failed to meet our pre-determined threshold of acceptable validity for STS velocity (r = 0.72, ES = 1.00) or power (r = 0.61, ES = 0.34).

SIGNIFICANCE

The LPT and iPhone App, but not the IMU, are valid tools for measuring STS velocity and power in community-dwelling older adults. Clinicians can use STS velocity obtained by either the LPT or App as a simple and valid proxy for functional status, which could help identify patients at high-risk of incident disability.