Kazumasa Yamada

Differences in muscle activation patterns during step recovery in elderly women with and without a history of falls

Background and aimsThis study aimed at comparing the patterns of muscle activation used in stepping to regain balance during a forward fall between subjects with and without a history of falling and at identifying the causes of functional deficits in recovery stepping.MethodsElderly women with and without a history of falling (fallers: nxa0=xa012, mean agexa0±xa0SDxa0=xa082.8xa0±xa04.5xa0years; non-fallers: nxa0=xa017, agexa0=xa081.4xa0±xa03.4xa0years) participated in the study. The subjects were suspended in a forward-leaning position by a lean-control cable with a load of 15xa0% of body weight and instructed to regain standing balance upon release by taking a single step forward. Electromyography (EMG) data were obtained from five lower extremity muscles on the stepping side, and the muscle activation patterns were compared between fallers and non-fallers.ResultsFallers had a shorter step length and slower step velocity than non-fallers. The EMG time-to-peak for the gastrocnemius muscle, which provides push-off prior to foot lift-off, was slower for fallers than for non-fallers, whereas the EMG onset times of the biceps femoris and gastrocnemius muscles were similar between the groups. The fallers exhibited significantly delayed muscle deactivation of the upper leg and increased co-contraction between the rectus femoris and biceps femoris during the stepping phase than did the non-fallers.ConclusionsThese findings suggest that the muscle activation pattern during the regain balance may reflect an inability to step forward rapidly in elderly women with a history of falls.

Effect of balance exercise in combination with whole-body vibration on muscle activity of the stepping limb during a forward fall in older women: A randomized controlled pilot study

This study investigated the effects of balance exercise combined with whole-body vibration (WBV) on step performance and lower limb muscle activity during simulated forward falls using the tether-release method in older women. Twenty older women were assigned to either a WBV plus balance exercise group (WBV, n=10) or a balance exercise without vibration group (standard balance exercise group [STE], n=10). WBV performed weight-bearing exercises on a WBV platform combined with other balance exercises as a home program, whereas STE performed the same exercises without WBV. The exercise volume was equal in both intervention groups (3×/week for 12 weeks×30 min/session). The EMG and kinematic data of the stepping leg from the balance recovery step were examined before and after the intervention. While both groups extended step length during forward falls after the intervention, only WBV increased step velocity. EMG analysis of the balance recovery step showed that both groups increased peak EMG of knee flexor and extensor muscles after intervention. After intervention, WBV increased peak EMG of the plantar flexors, which are used to exert the push-off forces just before the leg swing. Balance exercise in older women resulted in significant improvements in the balance recovery step after a simulated forward fall. WBV also had the additional benefit of improved step velocity, which was reflected in increased activity of the plantar flexors in the stepping leg.

A Study on Visual Search during the Trail Making Test: Analysis Using an Eye Tracker

The Trail Making Test A (TMT-A) is a task related to visual search. Therefore, performance in the TMT-A has a high possibility of being influenced by visual information, such as the arrangement of numbers. The purpose of this study was to measure eye movements during the TMT-A using an eye tracker, to analyze differences in enforcement and trace execution, and to examine appropriate inspection drawings as visual search tasks. Study 1 was performed in 14 young healthy subjects and Study 2 was performed in 6 young healthy subjects. The English and Japanese versions of the TMT-A were administered as usual and the subjects performed the traces in a sitting position. The eye movements of the subjects were measured during the task. We analyzed the combined motion angles of both eyes. We compared the average values (30 Hz/s) of movement in the horizontal (X-axis) and vertical (Y-axis) directions during the normal administration of the English and Japanese version of the TMT-A. We also compared the traces performed by the subjects. There were no differences in tracing or enforcement in the English version of the TMT-A. Especially in the vertical visualization operation, it was shown that the normal enforcement was fewer than the tracing, and almost no up-to-down search was performed. In contrast, the subjects performed visual searches in all directions during the Japanese version of the TMT-A.

Effect of ankle stretching combined with arm cycling on the improvement of calf muscle stiffness in patients with stroke: a pilot study

[Purpose] This study aimed to ascertain whether ankle stretching combined with arm cycling compared with that without arm cycling results in greater improvement in maximum dorsiflexion range of motion (ROM), calf muscle stiffness, and gait velocity in the affected limb of patients with stroke. [Participants and Methods] Random ABAB reversal design was used in this study involving nine patients with stroke. Participants performed 10u2005min of ankle plantar flexor stretching through weight bearing using the tilt table under the following 2 conditions: with or without arm cycling at 60 revolutions per minute. Pre- and post-stretching maximum ROM and passive plantar flexion torque were measured using a custom-made passive torque indicator. Stiffness was calculated based on passive torque-angle relationships. [Results] Maximum ROM and stiffness significantly improved after stretching in both conditions, whereas no changes in gait velocity were found. The difference in pre- and post-stretching stiffness was significantly greater in the stretching with arm cycling group. Change in maximum ROM showed no difference between both stretching conditions. [Conclusion] This study indicates that ankle plantar flexor stretching combined with arm cycling was more effective than that without cycling in improving calf muscle stiffness in the affected limb of patients with stroke.