Physical activity improves gaze and posture control in the elderly

Ageing is associated with a decrease in the quality of balance regulation, in particular through dysfunctions of gaze control and postural stabilization, which results in an increased risk of falling. Conversely, the practice of physical and sporting activities has been shown to improve every level of postural regulation. This study is to assess the effects of the practice of physical activities on vestibulospinal reflex and ocular movements of visual and vestibular origins in elderly people. Gaze control and posture stabilization were evaluated in 13 healthy aged women who regularly practised physical activities and in 13 healthy aged sedentary women of a similar age, by dynamic posturographic test with electromyography, as well as electronystagmography with caloric and rotational vestibular tests, ocular saccades, smooth pursuit and optokinetic tests. The gaze and posture control performance of the active group was better; the proprioceptive and vestibular sensitivities were higher, visual detection quality was good, and reaction time was low. Regular physical activity develops or maintains the efficiency of the reflexes involved in postural control, especially through adequate neurosensorial information, which allows the central integrative structures to generate a more appropriate motor response.     

Intertester reliability of assessing postural sway using the chattecx balance system

In this study, we examined intertester reliability of dynamic and static balance using the Chattecx Dynamic Balance System. Ten female and two male subjects were randomly assigned to two testers and completed ten, 10-second preprogrammed double- and single-leg test conditions. Balance was measured as postural sway in centimeters by the Chattecx Dynamic Balance System. Static balance consisted of the platform remaining stable, whereas dynamic balance consisted of the platform tilting in an anterior and posterior direction during testing. The protocols and average postural sway values were:1. Double-Leg Static Eyes Open ([unk] = .28 cm)2. Double-Leg Static Eyes Closed ([unk] = .37 cm)3. Double-Leg Dynamic Eyes Open ([unk] = .86 cm)4. Double-Leg Dynamic Eyes Closed ([unk] = 1.72 cm)5. Single-Leg Static Dominant Eyes Open ([unk] = .99 cm)6. Single-Leg Static Dominant Eyes Closed ([unk] = 1.70 cm)7. Single-Leg Static Nondominant Eyes Open ([unk] = .65 cm)8. Single-Leg Static Nondominant Eyes Closed ([unk] = 1.48 cm)9. Single-Leg Dynamic Dominant Eyes Open ([unk] = .99cm)10. Single-Leg Dynamic Nondominant Eyes Open ([unk] = .91 cm).The mean values of postural sway ranged from .28 cm to 1.72 cm for double-leg stance measures and from .65 cm to 1.70 cm for the single-leg stance measures. The intraclass correlations (ICCs)(2,1) ranged from poor to excellent (ICCs = .06 to .90) and the standard error of measurement (SEM) ranged from .06 to .34 for the 10 trials. We feel that variability exists between subjects and/or testers between trials. The wide range of reliability values suggests that further research should determine both intratester and intertester reliability using a variety of protocols for assessment of static and dynamic balance.     

The Reliability Of Three Isokinetic Knee-extension Angle-specific Torques

To determine the reliability of concentric quadriceps muscle torque at 30 degrees , 60 degrees , and 75 degrees of knee extension, 25 female university students were studied. Each subject was tested on the Kin-Com isokinetic dynamometer on 2 separate days, 7 days apart. The dynamometer's speed was set at 60 degrees ls. Intraclass correlation coefficients for 30 degrees , 60 degrees , and 75 degrees were 0.84 (p<.01), 0.87 (p<.01), and 0.83(p<.01), respectively. The standard errors of the measure were 5.92 N.m, 7.65 N.m, and 7.35 N.m, respectively. Based on the instrumentation and protocol used in this study, we believe angle-specific torques have good reliability. Because of the error size, clinicians using similar methodology to determine angle-specific torques should be cautious when comparing differences between angle-specific torques of less than 12 to 16 N.m.