HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Weerdesteyn, V. Articles by Duysens, J. Search for Related Content PubMed PubMed Citation Articles by Weerdesteyn, V. Articles by Duysens, J.

Age-Related Deficits in Early Response Characteristics of Obstacle Avoidance Under Time Pressure

¹ Department of Rehabilitation Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
² Sint Maartenskliniek Research, Development & Education, Nijmegen, The Netherlands.
³ Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.

Address correspondence to Vivian Weerdesteyn, PhD, Department of Rehabilitation Medicine, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands. E-mail: v.weerdesteyn{at}reval.umcn.nl

Background. Obstacles in the travel path are a frequent cause of falls among elderly persons. In obstacle avoidance under time pressure, elderly persons have been reported to be less successful than young persons, but possible age-related deficits at the neuromuscular control level have not been studied yet.

Methods. In the present study, obstacle avoidance reactions were investigated in 15 young and 9 older adults. While the participants walked on a treadmill, an obstacle was dropped in front of the left foot either in late stance, early swing, or mid-swing. Muscle activity in response to the obstacle was measured from the left biceps femoris (BF), rectus femoris (RF), tibialis anterior (TA), and medial head of gastrocnemius (GM). Avoidance success rates, as well as initial response latencies and response amplitudes over the first 50 ms of the response, were determined.

Results. In both young and older adults, a large initial response was consistently observed in BF at very short latencies (104–111 ms in the young group), especially for mid-swing obstacle presentations (yielding the highest time pressure). Onset latencies in the elderly group were delayed by 10 ms on average. Response amplitudes were larger in young than in older adults, most prominently in BF and RF, but with a similar tendency in TA. Both onset latency and response amplitude were significantly associated with avoidance success rates.

Conclusions. The results of the present study suggest that age-related deficits in the neuromuscular control of obstacle avoidance could play a role in the large numbers of obstacle-related falls in the elderly population.

This article has been cited by other articles:

				A. Queralt, V. Weerdesteyn, H. J. R. van Duijnhoven, J. M. Castellote, J. Valls-Sole, and J. Duysens The effects of an auditory startle on obstacle avoidance during walking J. Physiol., September 15, 2008; 586(18): 4453 - 4463. [Abstract] [Full Text] [PDF]