Investigation of a method for representing perceived standing position in the anterior-posterior direction.

Souta Ohtsubo, Hitoshi Asai, Pleiades Inaoka, Aoi Sugata, Myeongje Cho, Mai Nakamura
Purpose:

This study aimed to determine the accuracy and regularity of the “representing body tilt angle by using goniometer method” (goniometer method), which is capable of representing standing positions even when the position is perceived to be beyond the range in which the subject can hold the standing position.

Methods:

Thirteen anteroposterior standing positions (based on the foot pressure center position from 20% to 80% of foot length, in 5% increments) were randomly tested five times each for perception and expression, with breaks between trials. Higher values of % of foot length meant the position was more inclined anteriorly. The items measured were: the expressed body tilt angle (EBTA) of the subject's own body tilt angle (BTA) expressed by goniometer, the actual body tilt angle of the acromion (ABTA-a) (the angle between the line connecting the acromion and the lateral malleolus and the line parallel to the floor) and the actual body tilt angle of the great trochanter (ABTA-t) (the angle between the line connecting the great trochanter and lateral malleolus and the line parallel to the floor), which was calculated from the camera image of the ABTA. Correlation between the standing position and EBTA and ABTA and between EBTA and ABTA were examined, and regression equations were calculated.

Results:

There was a strong, significant correlation between standing position, EBTA, and ABTA. The relationship between EBTA and ABTA also showed a strong correlation. The correlation coefficients for each subject were higher than the overall group, and individual differences were found in the regression equations. The standing position with an EBTA of 90° in the regression equation also correlated with the QS position.

Conclusion(s):

There is a significant strong correlation between the standing position and ABTA, it’s considered useful to replace the standing position in the anteroposterior direction with BTA. In addition, when this method is applied to the representation of illusions, approximate formulas in the relationship between the standing position and EBTA must be obtained for each subject. Based on the relationship between the standing position with EBTA of 90° and the QS position, the QS position may be perceived as the reference for the vertical position.

Implications:

This methodology may help explore the importance of Achilles tendon proprioceptive information across different standing positions.

Funding acknowledgements:
This work was unfunded.
Keywords:
standing position
representing body tilt angle
perception of body tilt angle
Primary topic:
Research methodology, knowledge translation and implementation science
Second topic:
Neurology
Did this work require ethics approval?:
Yes
Name the institution and ethics committee that approved your work:
the institutional ethics committee of Kanazawa University
Provide the ethics approval number:
2022-352
Has any of this material been/due to be published or presented at another national or international conference prior to the World Physiotherapy Congress 2025?:
Yes

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