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Biomedical subjects

R W Soames

Publications and source records attributed to R W Soames.

10 recordsLinked to original sources
PubMed1992

The influence of moving auditory fields on postural sway behaviour in man.

Postural sway behaviour was assessed, using a standard biomechanical measuring platform, in 30 young subjects (15 men, 15 women) during 60 s of erect standing in various combinations of visual input and moving auditory fields. The sway parameters investigated were mean lateral, antero-posterior, radius and velocity of sway, the area within the sway profile and the length of the sway path. The findings support the view that moving auditory fields have a destabilising influence on postural sway behaviour, and suggest that under the appropriate conditions postural sway can be "driven" by the auditory environment.

Acoustic Stimulation↗
PubMed1991

The influence of stationary auditory fields on postural sway behaviour in man.

Postural sway behaviour was investigated in 30 young subjects (15 male and 15 female) during 60 s of erect standing, under various combinations of auditory and visual input. Sway was assessed using a standard biomechanical measuring platform, the output of which led directly to an online computer from which the following parameters were determined: mean lateral and antero-posterior sway, velocity and radius of sway, length of the sway path and area within the sway profile. A marked difference in sway behaviour between the sexes was observed, with women showing increased magnitudes of some sway parameters. Postural sway was significantly increased in conditions without visual feedback. The presence of an auditory field tends to have a destabilising influence on sway behaviour, with both the direction of the sound source and the type of auditory input being important variables. Nevertheless there appears to be no interaction between the visual and the auditory environment in the control of posture.

Adult↗
PubMed1989

The influence of initial posture on the sit-to-stand movement.

Head movements, ground reaction forces and electromyographic activity of selected muscles were recorded simultaneously from two subjects as they performed the sit-to-stand manouevre under a variety of conditions. The influence of initial leg posture on the magnitude of the various parameters under investigation was examined first. A preferred initial leg posture resulted in smaller magnitudes of head movement and ground reaction forces. EMG activity in some muscles, trapezius and erector spinae, decreased, while in others, quadriceps and hamstrings, it increased in the preferred leg posture. The decreases seen correlate with reductions in head movement observed. The effect of inhibiting habitual postural adjustments of the head and neck, by comparing "free" and "guided" movements was also examined. In guided movements there are significant reductions in head movement, ground reaction forces and EMG activity in trapezius, sternomastoid and erector spinae. It would appear that both initial leg posture and the abolition of habitual postural adjustment have a profound influence on the efficiency of the sit-to-stand manouevre. This preliminary study high-lights the practical importance of head posture in the diagnosis and treatment of movement disorders, as well as in movement education.

Humans↗
PubMed1988

Human intervertebral disc: structure and function.

This review begins with a brief introduction in which the development, blood supply and innervation of the intervertebral disc is considered, particularly as these may influence the following sections on structure and function. The three regions within the disc--that is, the nucleus pulposus, annulus fibrosus, and cartilage end plates--are considered in some detail. There appears to be no distinct border between the central nucleus pulposus and the outer annulus fibrosus, the main difference being in their fibrous structure. The fluid space is important in the nutrition of the disc, showing plastic deformation and recovery characteristics. The structural elements, both macroscopically and microscopically, together with the biochemical elements, are intimately related to function. The intervertebral disc should not be though of as a homogeneous and static structure; it has a heterogeneous composition and responds dynamically to applied loads. Neither should it be considered as an isolated structure because it interacts with the vertebral bodies, together constituting the vertebral unit. Furthermore, changes within the disc can, and do, have dramatic effects on vertebral column kinematics. The intervertebral disc is not inactive; it is capable of self-maintenance; in injury it can repair itself and has considerable regenerative properties.

Biomechanical Phenomena↗
PubMed1985

Foot pressure patterns during gait.

Peak pressure and temporal parameters of foot function were determined in 21 men and 11 women; few differences between men and women in any of the parameters were observed, either when walking barefoot or when wearing shoes. However, significant differences were observed when barefoot and shod walking were compared. The main influence of shoes appears to be in modifying the behaviour of the forefoot, by changing the pressure distribution across the metatarsal heads and increasing the contact times for the toes. The implications of such changes are discussed. Intersubject variability in the pattern and magnitude of the peak pressure distributions under the foot, which appear to be consistent in both the short and long term, may prove to be of importance in the clinical environment, by providing an individual baseline from which change can be measured. A new measure, the pressure-time integral, could be a more valuable single measure than either the peak pressure or the temporal parameters.

Adult↗