Muscle Strength and Physical Performance Are Associated with Reaction Time Performance in Older People

Relationship between Fear-Avoidance Beliefs and Reaction Time Changes Prior to and following Exercise-Induced Muscle Fatigue in Chronic Low Back Pain

Background

Reaction time is a reliable indicator of the velocity and efficiency of neuromuscular control and may be associated with fear-avoidance beliefs. However, the effect of exercise-induced muscle fatigue on reaction time in chronic low back pain (cLBP) and its relationship with fear-avoidance beliefs remains poorly understood.

Objectives

This study aimed to reveal the relationship between fear-avoidance beliefs and reaction time changes before and after exercise-induced muscle fatigue in cLBP.

Methods

Twenty-five patients with cLBP were tested by the Biering-Sorensen test (BST) to induce exhaustive muscle fatigue. Total reaction time (TRT), premotor time (PMT), and electromechanical delay (EMD) of dominated deltoid muscle were recorded by surface electromyography during the arm-raising task with visual cues before and after muscle fatigue. The mean difference (MD) of TRT (MDTRT), PMT (MDPMT), and EMD (MDEMD) was calculated from the changes before and after muscle fatigue. Fear-avoidance beliefs questionnaire (FABQ) was applied to evaluate fear-avoidance beliefs before muscle fatigue. In addition, the duration time of BST was recorded for each subject.

Results

TRT and PMT of dominated deltoid muscle were prolonged after exercise-induced muscle fatigue (Z = 3.511, p < 0.001; t = 3.431, p = 0.001), while there was no statistical difference in EMD (Z = 1.029, p = 0.304). Correlation analysis showed that both the MDTRT and MDPMT were positively correlated with FABQ (r = 0.418, p = 0.042; r = 0.422, p = 0.040).

Conclusions

These findings suggested that we should pay attention to both muscle fatigue-induced reaction time delay in cLBP management and the possible psychological mechanism involved in it. Furthermore, this study implied that FABQ-based psychotherapy might serve as a potential approach for cLBP treatment by improving reaction time delay. This trial is registered with ChiCTR2300074348.

Does physical activity attenuate the association between ambient PM2.5 and physical function?

BACKGROUND

Physical function (PF), such as muscle strength, performing daily activities, has gradually declined with the increase of age, causing the occurrence of disability and diseases burden. Air pollution exposure and physical activity (PA) were both linked to PF. We aimed to explore the individual and joint effects of particulate matter <2.5 μm (PM_2.5) and PA on PF.

METHODS

A total of 4537 participants and 12,011 observations aged ≥45 years old from the China Health and Retirement Longitudinal Study (CHARLS) cohort from 2011 to 2015 were included into the study. PF was assessed by a combined score of four tests, including grip strength, walking speed, sense of balance, and chair standing tests. Air pollution exposure data was from The ChinaHighAirPollutants (CHAP) dataset. The annual PM_2.5 exposure for each individual was estimated based on county-level resident addresses. We estimated the volume of moderate-to-vigorous physical activity (MVPA) by quoting metabolic equivalent (MET). Multivariate linear model was conducted for baseline analysis, and linear mixed model with random participant intercepts was constructed for cohort longitudinal analysis.

RESULTS

PM_2.5 was negatively associated with PF, while PA was positively associated with PF in baseline analysis. In cohort longitudinal analysis, a 10 μg/m³ increase in PM_2.5 was associated to a 0.025 point (95 % CI: -0.047, -0.003) decrease in PF score, and a 10-MET-h/week increase in PA was related to a 0.004 point (95 % CI: 0.001, 0.008) increase in PF score. The association between PM_2.5 and PF decreased by increased PA intensity, and PA reversed the detrimental effects between PM_2.5 and PF.

CONCLUSION

PA attenuated the association of air pollution with PF at both high and low levels of air pollution, implying that PA may be an effective behavior to reduce the adverse effects of poor air quality on PF.

[Malnutrition management of hospitalized patients with diabetes/hyperglycemia and hip fracture]

Introduction

The yearly incidence of hip fracture is very high, which generates significant healthcare and socioeconomic burden. These fractures can occur at any age, but the vast majority occur in people over 65 years of age and predominantly in women, due to the increased risk of menopause-associated osteoporosis. Type 2 diabetes mellitus (DM2), apart from altering glucose, lipid and protein metabolisms, also causes a deregulation of calcium, phosphorus and magnesium and dysfunction in bone metabolism. The prevalence of malnutrition in patients with hip fracture is also high, due to their advanced age, and the acute injury itself provokes catabolic and inflammatory responses that result in disease-related malnutrition and sarcopenia, which aggravates the patient's clinical condition. This article describes the results of the expert consensus and the responses of the panelists on the nutritional management in routine clinical practice of patients with diabetes/hyperglycemia hospitalized (non-critically ill) with hip fracture.

Mediating effect of lower extremity muscle strength on the relationship between mobility and cognitive function in Chinese older adults: A cross-sectional study

Aging is a multifactorial process associated with irreversible decline in mobility and cognitive function. However, the mechanisms underlying the relationship between mobility and cognitive function remain elusive. In specific, the mediating effect of muscle strength, which is essential to maintain mobility, on this relationship has yet to be clarified. Accordingly, we performed a cross-sectional study involving Chinese older adults to understand the role of muscle strength in the relationship between mobility and cognitive function. The cognitive function and physical performance of 657 community-dwelling participants aged over 65 years old were observed. Cognitive function was assessed using the Mini-Mental State Examination, whereas physical performance, including mobility and muscle strength, was measured via Timed Up-and-Go Test and knee extension strength measurement. Data were statistically analyzed using PROCESS Model 4 developed by Hayes, and 595 complete data were finally included. Physical performance (mobility and muscle strength) was significantly correlated with cognitive function (p &lt; 0.01). Muscle strength was negatively correlated with mobility (r = −0.273, p &lt; 0.001) and positively correlated with cognitive function (r = 0.145, p &lt; 0.001). Muscle strength accounted for 20.1% of the total mediating effects on the relationship between mobility and cognitive function, which revealed the partial mediating role of lower extremity muscle strength in this relationship.

Is There a Relationship Between Foot Reaction Time and Ankle Frontal Plane Torque in Female Soccer Athletes? A Pilot Study

The purpose of this study was to determine if a relationship existed between foot reaction time and ankle frontal plane peak torque in female soccer athletes. A one-shot case study design was selected for this investigation. Seventeen female college athletes volunteered to participate. Right and left foot reaction time measurements were assessed using 3×4 switch mats interfaced with a precise timing counter. Participants stood in front of the mat with eyes closed and responded to the auditory stimulus by touching the mat as fast as possible with their foot. Two trials were conducted per foot, and the best time was used to determine the reaction time score per foot. An isokinetic dynamometer assessed inversion and eversion peak torque for both right and left ankle joint at 120°/sec. Left peak torque eversion and right foot reaction time demonstrated a significant negative moderate relationship (r = -0.530; p value = 0.03). Left ankle peak torque eversion does have a significant moderate negative relationship to reaction time of the right foot; therefore, evasive dribbling movements which requires inversion and eversion torque could directly affect foot reaction time, resulting in improved dribbling performance for soccer athletes.

Configurations of the driving factors promoting China's commercial health insurance: A comparative qualitative analysis based on the technology–organization–environment framework

With the nation's remarkable improvement in living standards, China's health insurance system cannot satisfy people's higher demands; therefore, it is necessary to promote the supply of commercial health insurance (CHI) in China. Based on the technology–organization–environment (TOE) framework, this study constructs a novel analysis framework to investigate the driving path of China's CHI. Employing the data of 31 provincial regions of China in 2018, a fuzzy-set qualitative comparative analysis is conducted to analyze configurations. We also adopt a necessary condition analysis in the robustness check to examine the necessary conditions, determining that no necessary relationship exists between possible conditions and the performance of CHI. More particularly, three sufficient configurations, TOE strategy, government attention (GA)–environment adaptability (EA)–citizen demand (CD) strategy, and dual EA–CD strategy are demonstrated to achieve high performance, and the other three configurations of technological management capability (TMC)–EA-CD strategy, technological infrastructure (TI)–EA strategy, and combined TI–TMC–EA strategy do not result in high performance. In addition, technological conditions (TI and TMC) and EA are relatively more important than the other configurations. Notably, government departments' financial expenditure is found to have a negative effect on CHI promotion.

Association of military-specific reaction time performance with physical fitness and visual skills

Background

The aim of the present study was to explore whether military-specific reaction time (RT) test performance is affected by individuals' physical and visual skills.

Method

In a single testing session, the military-specific Simple and Go, No-Go RT, aerobic power (20-m Multistage Shuttle Run test), maximal upper- and lower-body mechanical capacities (bench press and squat against different loads), and visual skills (multiple object tracking and dynamic visual acuity) of 30 young men (15 active-duty military personnel and 15 sport science students) were evaluated.

Results

The main findings revealed that the Simple RT and Go, No-Go RT presented (1) with aerobic power non-significant small correlations in military personnel (r = -0.39 and -0.35, respectively) and non-significant negligible correlations in sport science students (r = -0.10 and 0.06, respectively), (2) inconsistent and generally non-significant correlations with the maximal mechanical capacities of the upper- and lower-body muscles (r range = -0.10, 0.67 and -0.27, 0.48, respectively), (3) non-significant correlations with visual skills (r magnitude ≥ 0.58) with the only exception of the Go, No-Go RT that was significantly correlated to all visual variables in the group of students (i.e., students who achieved better results during visual tests had shorter RT; r magnitude ≥ 0.58), and (4) none of the physical and visual variables significantly predicted the Simple RT or Go, No-Go RT.

Conclusion

Altogether, these results indicate that military-specific RT performance is generally independent of physical and visual skills in both military personnel and active university students.

Exploring the association between handgrip, lower limb muscle strength, and physical function in older adults: A narrative review

Widely used in daily practice, handgrip strength (HGS) is a low cost, easy-to-use, and portable test to assess overall muscle and physical function. It can be used as a stand-alone or a first-line tool for evaluating muscle weakness, though controversy surrounds its use for assessing global or lower limb muscle function. Lower limb mobility and physical activity are reduced with advancing age. This decline is difficult to quantify with isokinetic or isometric devices in routine settings (hospital and nursing home). For this narrative review we explored and summarized the findings of studies that investigated the association between HGS, lower limb muscle strength, and physical performance in older adults. The review also provides directions for future research. We noted contrasting findings for an association between HGS, lower limb strength, and physical performance. We found insufficient evidence for endorsing the handgrip dynamometer as a definitive tool for measuring overall muscle strength and physical function. More evidence is needed from comparable studies involving larger samples of men and women and investigating other areas such as lifestyle, daily physical activity levels, and health-related disorders.

Sarcopenia Prevalence and Risk Factors among Residents in Aged Care

The aim of this study was to investigate the prevalence of sarcopenia and associated risk factors among older adults living in three residential aged care (RAC) facilities within Auckland, New Zealand. A total of 91 older adults (63% women, mean age ± SD; 86.0 ± 8.3 years) were recruited. Using the European Working Group on Sarcopenia in Older People criteria, sarcopenia was diagnosed from the assessment of: appendicular skeletal muscle mass/height², using an InBody S10 body composition analyser and a SECA portable stadiometer or ulna length to estimate standing height; grip strength using a JAMAR handheld dynamometer; and physical performance with a 2.4-m gait speed test. Malnutrition risk was assessed using the Mini Nutrition Assessment–Short Form (MNA-SF). Most (83%) of residents were malnourished or at risk of malnutrition, and 41% were sarcopenic. Multivariate regression analysis showed lower body mass index (Odds Ratio (OR) = 1.4, 95% CI: 1.1, 1.7, p = 0.003) and lower MNA-SF score (OR = 1.6, 95% CI: 1.0, 2.4, p = 0.047) were predictive of sarcopenia after controlling for age, level of care, depression, and number of medications. Findings highlight the need for regular malnutrition screening in RAC to prevent the development of sarcopenia, where low weight or unintentional weight loss should prompt sarcopenia screening and assessment.