Association between leg strength and muscle cross-sectional area of the quadriceps femoris with the physical activity level in octogenarians

Decrements of mobility and power in recreationally active septuagenarians is related to loss of force, but not slowing of the muscle: a 5-year longitudinal study

A lesser 6-min walk distance (6MWD) and timed up-and-go (TUG) in old compared with young adults was previously linked to slowing of muscle contractile properties. The purpose of the present study was to determine whether any further reductions in 6MWD and TUG over a 5-year period in septuagenarians are associated with further slowing of muscle contractile properties. We measured muscle function by a countermovement jump, isometric maximal knee extensor strength (MVC) on a dynamometer and quadriceps muscle size by magnetic resonance imaging (MRI) in 17 older women (71.1 ± 2.8 y) and 17 older men (71.3 ± 4.1y). Performance in TUG and 6MWD were reduced over the 5-year period, irrespective of sex (P < 0.001), and both were correlated with power at both baseline and follow-up (R ≥ 0.53; P ≤ 0.001). Jump take-off velocity (V_CMJ) was slower at follow-up (P < 0.01) and correlated with 6MWD and TUG at both baseline and follow-up in both sexes (R ≥ 0.54; P ≤ 0.001). However, the relationship between 'body mass: maximal muscle force ratio' with V_CMJ was not significantly changed, indicating that the lower V_CMJ was attributable to muscles working at a higher relative load, hence a lower part of the force-velocity relationship, due to a reduction in MVC (body mass had not changed significantly), rather than slowing of the muscle. The lower V_CMJ in women than men (P < 0.001) was likewise attributable to a lower MVC rather than slower contractile properties in women. In conclusion, the decrement in 6MWD and TUG in septuagenarians is due to a loss of muscle mass, rather than further loss of muscle quality.

The influence of isokinetic peak torque and muscular power on the functional performance of active and inactive community-dwelling elderly: a cross-sectional study

OBJECTIVE

To verify the importance of the isokinetic muscular torque and power of knee extensors and flexors on the functional performance of active and inactive elderly women.

METHODS

A cross-sectional observational study was conducted with 116 community-dwelling women (≥60 years old) without severe cognitive and/or motor dysfunction. Isokinetic muscle function was measured by peak torque and muscle power at 60°/s (5 repetitions) and 180°/s (15 repetitions), respectively. Mobility was evaluated by means of the Timed Up and Go test (TUG) and the Habitual Gait Speed (HGS) test. Balance was evaluated via the alternate step and semitandem tests. Lower limb strength was assessed using the Sit-to-stand test. Univariate and multivariate logistic regression analysis was used to determine association between independent and dependent variables (α=0.05).

RESULT

Active elderly women had better muscle function and functional performance than inactive elderly women for almost all variables. Peak torque and muscular power of knee extensor muscles explained the dynamic balance, mobility, and lower limb strength among inactive elderly women (OR: 0.89-0.95; p<0.05). Muscular power of knee flexors influenced tasks that required mobility and lower limb strength among active elderly (OR: 0.82-0.87; p<0.05).

CONCLUSIONS

The muscular power of knee flexors was shown to be more important for the functional performance of active elderly women. The muscular power of knee extensors had a stronger influence on the performance of the inactive elderly women.

Functional Ability, Frailty and Risk of Falls in the Elderly: Relations with Autonomy in Daily Living

The objective of this research was to determine the differences in autonomy in both basic activities of daily life in instrumental activities of daily life, as well as functional capacity, fragility and risk of falls between an active group and a sedentary group. The individual associations of functional capacity, fragility and risk of falls were also analyzed, with autonomy in basic activities of daily living and in instrumental activities of daily living in the active group. In this cross-sectional investigation, 139 people from Huelva between 65 and 87 years of age were evaluated (Mean (M) = 73.1; standard deviation (SD) = 5.86); 100 were women and 39 men. The active and sedentary group were composed of 69 and 70 elderly people, respectively. The active group carried out a physical activity program. Among the results, a significant effect was seen in the multivariate contrast of the study variables, V = 0.24, F (5, 137) = 8.58, and p < 0.001; while in the linear regressions in the active group, the Vivifrail with the Barthel Index (Δ Adj. R2 = 0.15) and with the Lawton and Brody Scale (Δ Adj. R2 = 0.22) were used. In conclusion, the active group presented better values in all the variables evaluated in comparison to the sedentary group, establishing statistically significant differences. In addition, in the active group, it has been found that functional capacity is a significant predictive variable of autonomy in instrumental activities of daily living (22%), while fragility and the risk of falls are significant predictors of autonomy in activities of basic daily life (15%).

Muscle profile and cognition in patients with Alzheimer's disease dementia

INTRODUCTION

Neurodegenerative disease is one of the main contributing factors affecting muscle atrophy. However, this intriguing brain-muscle axis has been explained by the unsubstantial mechanisms. Although there have been several studies that have evaluated the muscle profile and its relation to cognition in patients with dementia, there is still lack of data using standardized methods and only few published studies on Korean populations. The objective of this study is to evaluate the relationship of muscle mass and strength to cognition in patients with Alzheimer's disease dementia (AD).

METHODS

We recruited 91 patients with probable AD without weakness. We assessed patients' basic demographic characteristics, vascular risk, body mass index, and global cognitive assessment scores. Muscle mass was measured using body dual-energy X-ray absorptiometry. Muscle strength was assessed by isokinetic knee extensor using an isokinetic device at an angular velocity of 60°/s in nm/kg.

RESULTS

The muscle mass and strength were not related to each other in both male and female groups. Only muscle strength, but not muscle mass, was negatively related to cognition. After adjusting for covariates, the relationship between muscle strength and cognition still remained in the male group, however, was attenuated in the female group.

CONCLUSIONS

In patients with AD dementia, abundant muscle mass did not mean strong power. The simple lower-extremity muscle strength assessment is more effective in predicting cognition than a muscle mass measure in male patients.