Dataset Information

Identification of muscle weakness in older adults from normalized upper and lower limbs strength: a cross-sectional study.

ABSTRACT:

Background

To propose cut-off points for older adults' weakness for upper and lower limbs muscle strength normalized by body size with the ratio standard/muscle quality and allometric scaling.

Methods

Ninety-four community-dwelling older adults (69.1% women) were assessed for 49 body-size variables (anthropometry, body composition and body indexes), handgrip strength (HGS), one maximum repetition measurement for knee extensors (1RM), isokinetic knee extension peak torque at 60°/s (PT), and six-minute walk test (6MWT). Ratio standard or muscle quality (muscle strength/body size) and allometric scaling (muscle strength/body size^b; when ^b is the allometric exponent) were applied for body-size variables significantly correlated with HGS, 1RM and PT. Cut-off points were computed according to sex based on mobility limitation (6MWT < 400 m) with ROC curve and Youden index.

Results

Absolute HGS, 1RM and PT cut-off points were not adequate because they were associated with body size (r > 0.30). But it was corrected with muscle strength normalization according to body size-variables: HGS (n = 1); 1RM (n = 24) and PT (n = 24). The best cut-off points, with the highest area under the curve (AUC), were found after normalization for men: HGS/forearm circumference (1.33 kg/cm, AUC = 0.74), 1RM/triceps skinfold (4.22 kg/mm, AUC = 0.81), and PT/body mass*height^0.43 (13.0 Nm/kg*m^0.43, AUC = 0.94); and for women: HGS/forearm circumference (1.04 kg/cm, AUC = 0.70), 1RM/body mass (0.54 kg/kg, AUC = 0.76); and PT/body mass^0.72 (3.14 Nm/kg^0.72; AUC = 0.82).

Conclusions

Upper and lower limbs muscle weakness cut-off points standardized according to body size were proposed for older adults of both sexes. Normalization removes the effect of extreme body size on muscle strength (both sexes) and improves the accuracy to identify weakness at population level (for women, but not in men), reducing the risk of false-negative/positive cases.

SUBMITTER: Abdalla PP

PROVIDER: S-EPMC8684151 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundDistal radius fractures are common fractures in older adults and associated with increased risk of future functional decline and hip fracture. Whether lower limb muscle strength and balance are impaired in this patient population is uncertain. To help inform rehabilitation requirements, this systematic review aimed to compare lower limb muscle strength and balance between older adults with a distal radius fracture with matched controls, and to synthesise lower limb muscle strength and balance outcomes in older adults with a distal radius fracture.MethodsWe searched Embase, MEDLINE, and CINAHL (1990 to 25 May 2022) for randomised and non-randomised controlled clinical trials and observational studies that measured lower limb muscle strength and/or balance using instrumented measurements or validated tests, in adults aged ≥ 50 years enrolled within one year after distal radius fracture. We appraised included observational studies using a modified Newcastle-Ottawa Scale and included randomised controlled trials using the Cochrane risk-of-bias tool. Due to the clinical and methodological heterogeneity in included studies, we synthesised results narratively in tables and text.ResultsNineteen studies (10 case-control studies, five case series, and four randomised controlled trials) of variable methodological quality and including 1835 participants (96% women, mean age 55-73 years, median sample size 82) were included. Twelve included studies (63%) assessed strength using 10 different methods with knee extension strength most commonly assessed (6/12 (50%) studies). Five included case-control studies (50%) assessed lower limb strength. Cases demonstrated impaired strength during functional tests (two studies), but knee extension strength assessment findings were conflicting (three studies). Eighteen included studies (95%) assessed balance using 14 different methods. Single leg balance was most commonly assessed (6/18 (33%) studies). All case-control studies assessed balance with inconsistent findings.ConclusionCompared to controls, there is some evidence that older adults with a distal radius fracture have impaired lower limb muscle strength and balance. A cautious interpretation is required due to inconsistent findings across studies and/or outcome measures. Heterogeneity in control participants' characteristics, study design, study quality, and assessment methods limited synthesis of results. Robust case-control and/or prospective observational studies are needed.RegistrationInternational prospective register of systematic reviews (date of registration: 02 July 2020, registration identifier: CRD42020196274).

Project description:BackgroundMusculoskeletal disorders are the most frequent occupational diseases in Europe. However, their multifactorial aetiology poses several challenges concerning not only the estimation of relative prevalence rates across occupational groups but also how the co-occurrence of known risk factors might differ between disorders of the upper and lower limbs. Against this background, the following objectives are pursued: (1) to estimate the relative odds and prevalence rates of self-reported disorders of the upper limbs and/or shoulders and neck (upper body) and the lower limbs for major ISCO-88 occupational groups, (2) to evaluate to what extent the associations between known risk factors differ for musculoskeletal disorders of the upper body and the lower limbs.MethodsStatistical analysis of cross-sectional data from the European Working Conditions Survey 1995-2010. The probability of reporting upper body and lower limbs pain in the survey sample 2010 is estimated by mixed logistic regression models using the Markov chain Monte Carlo Sampler. Independent variables include some known physical and psychosocial risk factors.ResultsConcerning the first objective, an excess risk of reporting musculoskeketal disorders of the upper body was observed among craft workers (ISCO 7), machine operators (ISCO 8) and workers in elementary occupations (ISCO 9). Concerning musculoskeletal disorders of the lower limbs, service and sales workers (ISCO 5) and workers in ISCO groups 7, 8 and 9 reported symptoms more frequently. Regarding the second objective, similar association patterns were observed for upper body and lower limbs symptoms. Major physical risk factors associated with both symptom types were very frequent exposure to tiring positions, carrying heavy loads and performing repetitive tasks. Standing appears to be an important risk factor for lower limbs symptoms only.ConclusionsResults suggest that the unequal burden of exposure has not changed substantially across occupational groups since 1995, and that there is urgent need of delivering and evaluating the effects of specific interventions targeting workers at high risk of developing musculoskeletal disorders.

Project description:BackgroundHigher maximal- and explosive strength is associated with better physical function among older adults. Although the relationship between isometric maximal strength and physical function has been examined, few studies have included measures of isometric rate of force development (RFD) as a measure of explosive strength. Furthermore, little is known about the oldest old (>80 years), especially individuals who receive home care and use mobility devices. Therefore, the aim of this study was to examine the association between maximal- and explosive muscle strength with physical function in community-dwelling older adults receiving home care.MethodsAn exploratory cross-sectional analysis including 107 (63 females and 43 males) community-dwelling older adults [median age 86 (interquartile range 80-90) years] receiving home care was conducted. Physical function was measured with five times sit-to-stand (5TSTS), timed 8-feet-up-and-go (TUG-8ft), preferred-, and maximal gait speed. Maximal strength was assessed as maximal isometric voluntary contraction (MVC) and explosive strength as RFD of the knee extensors. We used linear regression to examine the associations, with physical function as dependent variables and muscle strength (MVC and RFD) as independent variables.ResultsMVC was significantly associated with 5TSST [standardized regression coefficient β = -0.26 95% CI (-0.45, -0.06)], TUG-8ft [-0.6 (-0.54, -0.17)], preferred gait speed [0.39 (0.22, 0.57)], and maximal gait speed [0.45 (0.27, 0.62)]. RFD was significantly associated with 5TSST [-0.35 (-0.54, -0.17)], TUG-8ft [-0.43 (-0.60, -0.27)], preferred gait speed [0.40 (0.22, 0.57)], and maximal gait speed [0.48 (0.31, 0.66)].ConclusionsHigher maximal- and explosive muscle strength was associated with better physical function in older adults receiving home care. Thus, maintaining and/or improving muscle strength is important for perseverance of physical function into old age and should be a priority.

Project description:With advanced age, there is a loss of reaction speed that may contribute to an increased risk of tripping and falling. Avoiding falls and injuries requires awareness of the threat, followed by selection and execution of the appropriate motor response. Using event-related potentials (ERPs) and a simple visual reaction task (RT), the goal of our study was to distinguish sensory and motor processing in the upper- and lower-limbs while attempting to uncover the main cause of age-related behavioral slowing. Strength (amplitudes) as well as timing and speed (latencies) of various stages of stimulus- and motor-related processing were analyzed in 48 healthy individuals (young adults, n = 24, mean age = 34 years; older adults, n = 24, mean age = 67 years). The behavioral results showed a significant age-related slowing, where the younger compared to older adults exhibited shorter RTs for the upper- (222 vs. 255 ms; p = 0.006, respectively) and the lower limb (257 vs. 274 ms; p = 0.048, respectively) as well as lower variability in both modalities (p = 0.001). Using ERP indices, age-related slowing of visual stimulus processing was characterized by overall larger amplitudes with delayed latencies of endogenous potentials in older compared with younger adults. While no differences were found in the P1 component, the later components of recorded potentials for visual stimuli processing were most affected by age. This was characterized by increased N1 and P2 amplitudes and delayed P2 latencies in both upper and lower extremities. The analysis of motor-related cortical potentials (MRCPs) revealed stronger MRCP amplitude for upper- and a non-significant trend for lower limbs in older adults. The MRCP amplitude was smaller and peaked closer to the actual motor response for the upper- than for the lower limb in both age groups. There were longer MRCP onset latencies for lower- compared to upper-limb in younger adults, and a non-significant trend was seen in older adults. Multiple regression analyses showed that the onset of the MRCP peak consistently predicted reaction time across both age groups and limbs tested. However, MRCP rise time and P2 latency were also significant predictors of simple reaction time, but only in older adults and only for the upper limbs. Our study suggests that motor cortical processes contribute most strongly to the slowing of simple reaction time in advanced age. However, late-stage cortical processing related to sensory stimuli also appears to play a role in upper limb responses in the elderly. This process most likely reflects less efficient recruitment of neuronal resources required for the upper and lower extremity response task in older adults.