The validity of physique-based inverted pendulum models of postural sway behaviour.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
J Atha
Publications and source records attributed to J Atha.
Stature loss from sustained gentle body loading.
The effects of low levels of loading on spinal creep have been investigated in nine young men aged between 19 and 24 years. The stimulus for the project was an interest in the potential use of stadiometry in evaluating selected classes of patients with spinal disorders. Underlying the experiment was the view that if gentle spinal loadings cannot be differentiated sensitively in normal young adults then the feasibility of using stadiometric measurements to identify patients with decreased lability is questionable. Subjects were measured on a precision stadiometer before and after 25 minutes of free standing and quiet walking, and the resultant stature losses compared with the more substantial losses observed following steady running. All measurements were made following the same presession routine, at exactly the same time on three separate mornings. It was observed that while no appreciable stature loss followed standing (mean = 0.01 mm; SE = 0.65 mm; p > 0.05) even quiet walking had a measurable and statistically significant effect (mean = 1.82 mm; SE = 0.49 mm; p < 0.01). Compared with these, steady running produced almost 2 1/2 times as great a loss (mean = 4.32 mm; SE = 0.83 mm; p < 0.01). It is concluded: (a) that erect standing provides a useful neutral baseline from which the changes associated with spinal loading and unloading may be measured; (b) that the effects of even gentle spinal loadings may be differentiated sensitively by precision stadiometry; and (c) that easy walking is one such gentle stimulus with detectable effects in normal young men.
Adult↗
The damaging punch.
The mechanical properties of a boxing punch have been determined using several techniques. The results are consistent with the medical consequences of boxing discussed in the report of the Board of Science and Education Working Party on boxing. Data were gathered from a world ranked British professional heavyweight, Frank Bruno, as he punched an instrumented, padded target mass suspended as a ballistic pendulum. Within 0.1 s of the start the punch had travelled 0.49 m and attained a velocity on impact of 8.9 m/s. The peak force on impact of 4096N (0.4 ton), attained within 14 ms of contact, represents a blow to the human head of up to 6320N (0.63 ton). The transmitted impulse generated an acceleration of 520 m/s2 (53 g) in the target head. For comparison an equivalent blow would be delivered by a padded wooden mallet with a mass of 6 kg (13 lbs) if swung at 20 mph.
Athletic Injuries↗