Changes in stature with spinal loading and their relation to the perception of exertion or discomfort

Measurements of stature can now be made to an accuracy of better than 1 mm and decreases in stature have been shown to relate closely to the biomechanical load on the spine. In order to test the hypothesis that they relate also to psychophysical factors, observations were made at Linköping and Liverpool of the changes resulting: (1) from standing with different vertical loads compared with ratings of discomfort; (2) from lying supine but inverted, for comparison with ratings for relaxation and comfort; and (3) after running, compared with ratings of perceived exertion. The results confirm that changes in stature are related not only to the biomechanical load on the spine but also to the psychophysical ratings.