Relationship between the ability to maintain posture and
muscle strength in healthy young females
Ability to maintain posture and muscle strength were measured in 48 normal young females.
Using a stabilometer, total shift length of the center of gravity (LNG) swayed over 30 seconds,
LNG per second (LNG/T) and LNG per enveloped area (LNG/E.A.) were measured with opened
and closed eyes in the normal Romberg position. One-leg balancing time was measured with opened
and closed eyes 3 times each, and grip strength and back strength were also measured. Exercise
history in junior high school and high school days was investigated using questionnaires.
Measurements of LNG, LNG/T and LNG/E.A. and one-leg balancing test with opened eyes were
significantly correlated to the measurements of these parameters with closed eyes, in each. There
were, however, no significant correlations between the various measurements of postural sway and
the results of one-leg balancing tests, with opened and closed eyes. Measurements of grip strength
and back strength were not significantly correlated to parameters of the ability to maintain posture,
namely LNG, LNG/T, LNG/E.A. and one-leg balancing tests. One-leg balancing time with closed
eyes in the EX group who had an exercise history during high school was significantly longer than
that in the N-EX group with not have an exercise history in either junior high school or high school,
or only had a history of exercise in junior high school, though there were no significant differences
in LNG, LNG/T, LNG/E.A. with opened and closed eyes, one-leg balancing time with eyes opened,
and muscle strength in the EX and N-EX groups.
The present result suggests that the significance of measuring sway at the center of gravity in the
body while standing on both feet was differrent from the significance of measuring one-leg
balancing time, and that the one-leg balancing test can not substitute for measuring sway at the
center of gravity. It was presumed that regular exercise habit in the recent past might contribute
to an improvement in the ability to maintain one-leg standing balance by means of feedback control
of the lower limb muscles.
(Rep. Res. Cent. Phys. Ed. 27 : 94-102, 1998)
東京慈恵会医科大学臨床検査医学 Department of Laboratory Medicine, The Jikeikai University School of Medicine