Biomedical subjects

Ben Sidaway

Publications and source records attributed to Ben Sidaway.

5 recordsLinked to original sources

PubMed2006

Effects of long-term gait training using visual cues in an individual with Parkinson disease.

BACKGROUND AND PURPOSE: In an attempt to improve the gait of people with Parkinson disease (PD), researchers have examined the effect of visual cues placed on the floor. These studies typically have used a single session of training with such cues and have not examined the long-term carryover of such training. In the present study, therefore, gait was analyzed during uncued, cued, and retention phases, each lasting 1 month. SUBJECT: A 78-year-old woman who had been diagnosed with PD 12 years previously (Hoehn and Yahr classification of disability, stage III) volunteered for the study. METHODS: During the initial uncued gait phase, the subject was required to walk a distance of 10 m as many times as she could in 30 minutes, 3 times per week for 4 weeks. During the 4-week cued gait phase, visual cues were placed on the floor along the 10-m walkway. The cues were initially 110% of the uncued step length and were later increased to 120%. Following this cued gait phase, the subject's gait was recorded periodically for 1 month without cues available. Step length, gait speed, and 2-dimensional lower-limb kinematics were compared within and across the 3 experimental phases. Celeration lines were calculated for the initial uncued phase and then extrapolated across the cued training and uncued retention phases. Binomial tests were used to analyze the significance of changes from the initial phase of the experiment. RESULTS: Step length (0.53-0.56 m) and gait speed (0.77-0.82 m x s(-1)) were essentially unchanged during uncued gait training after the first day; however, during the cued gait phase, gait speed improved, from 0.87 m x s(-1) to 1.13 m x s(-1), as step length was increased with visual cues. Improvements in step length (0.68 m) and gait speed (1.08 m x s(-1)) were still evident 1 month following the removal of the cues. Analyses of angle-angle diagrams and phase-plane portraits revealed that training with visual cues increased hip and knee range of motion and engendered more stable motor control of the lower limb. DISCUSSION AND CONCLUSION: In contrast to previous studies in which the benefits of visual cueing were relatively short-lived, in this study, 1 month of gait training with visual cues was successful in establishing a lasting improvement in gait speed and step length while increasing the stability of the underlying motor control system.

Aged↗

PubMed2005

Can mental practice increase ankle dorsiflexor torque?

BACKGROUND AND PURPOSE: Mental practice has been shown to be effective in increasing the force production of the abductor digiti minimi muscle in the hand. The aim of this study was to determine whether mental practice could produce strength gains in the larger ankle dorsiflexor muscles, which are important during walking. SUBJECTS: Twenty-four subjects were randomly assigned to a physical practice group, a mental practice group, or a control group (8 subjects per group). METHODS: In the practice groups, subjects either physically or mentally practiced producing maximal isometric contractions for 3 sets of 10 repetitions, 3 times per week for 4 weeks. Changes in mean peak isometric torque normalized to body weight and the resulting percentage of improvement were analyzed across the 3 groups. RESULTS: Differences in raw torque production after training in the 2 practice groups resulted in significant percentages of improvement for the physical practice group (25.28%) and the mental practice group (17.13%), but not for the control group (-1.77%). The 2 practice groups were not statistically different in their maximal torque-generating capacity after training. DISCUSSION AND CONCLUSION: These findings show that mental practice in people without impairments can lead to an increase in torque production similar to that produced by physical practice. Such a technique may prove to be a useful adjunct to traditional treatment options aimed at increasing muscle strength.

Adult↗

PubMed2004

The effect of cane length on the haptic perception of height.

PURPOSE: The purpose of this investigation was to determine whether the ability to haptically perceive object height is a function of the length of cane being wielded by blindfolded individuals. METHOD: Fifteen sighted females between the ages of 18 and 25 years volunteered to participate in the study. Five different heights of wooden blocks were haptically explored with four different cane lengths (0.92, 1.22, 1.37 and 1.67 m), cane length order being randomized across 2 days of testing. Subjects were asked to report whether the explored block's height was taller, shorter, or equal to that of a previously presented standard block. The percentages of correct judgments for each cane and block height combination were subjected to statistical analysis. RESULTS: The analysis revealed significant main effects for cane length, F (3, 42) = 9.47, p < 0.0001, and block height, F (4, 56) = 17.69, p < 0.0001. The interaction of cane length and block height was not significant, F < 1. The accuracy of haptic perception improved with decreased cane length and increased difference in height from the standard block. CONCLUSIONS: Contrary to previous research on haptic perception in which probe length was found not to affect judgment accuracy, the present study found a marked influence of cane length on perceptual accuracy. This finding indicates that length is an important property that should be taken into account when prescribing canes for the visually impaired.

Adolescent↗

PubMed2002

Acute effects of stretching on the neuromechanical properties of the triceps surae muscle complex.

Previous research has shown that an acute bout of passive muscle stretching can diminish performance in certain movements where success is a function of maximal force and/or power output. Two possible mechanisms that might account for such findings are a change in active musculotendinous stiffness and a depression of muscle activation. To investigate the likelihood of these two mechanisms contributing to a post-stretch reduction in performance, we examined the acute effects of stretching on the active stiffness and muscle activation of the triceps surae muscle group during maximal single-joint jumps with movement restricted to the ankle joint. Ten males performed both static (SJ) and countermovement (CMJ) jumps before and after passively stretching the triceps surae. Electrical activity of the triceps surae during each jump was determined by integrating electromyographic recordings (IEMG) over the course of the movement. Triceps surae musculotendinous stiffness was calculated before and after stretching using a technique developed by Cavagna (1970). Following stretching, a significant decrease [mean (SD) 7.4 (1.9)%; P<0.05] in jump height for the CMJ occurred, but for the SJ, no significant ( P>0.05) change in jump height was found. A small but significant decrease [2.8 (1.24)%; P<0.05] in stiffness was noted, but the magnitude of this change was probably not sufficient for it to have been a major factor underlying the decline in CMJ performance. Paradoxically, after stretching, the SJ exhibited a significant ( P<0.05) decrease in IEMG, but the IEMG for the CMJ remained unchanged ( P>0.05). It appears that an acute bout of stretching can impact negatively upon the performance of a single-joint CMJ, but it is unlikely that the mechanism responsible is a depression of muscle activation or a change in musculotendinous stiffness.

Achilles Tendon↗

PubMed1999

Distributed Control in Rapid Sequential Aiming Responses.

The preparation and on-line control of short, rapid sequential aiming responses were studied in 3 experiments. Participants (N = 12 in Experiments 1 and 2, and 20 in Experiment 3) produced 3-segment responses (a) within self-initiation, simple reaction time (RT), and choice RT paradigms (Experiment 1); (b) without visual feedback under self-initiation conditions (Experiment 2); and (c) with and without visual feedback under simple RT conditions (Experiment 3). In all conditions in which participants initiated movement in response to an external imperative signal, the 2nd response segment was performed consistently slower than preceding and succeeding response segments. That pattern of segmental movement times was found whether or not visual feedback was available but was not evident when participants self-initiated their responses with or without visual feedback. The findings rule out the possibility that subjects' use of visual feedback is responsible for the slowing of the 2nd response segment under RT conditions and suggest that the programming of rapid sequential aiming responses can be distributed in pre- and postinitiation intervals.

Journal Article↗