Voluntary and Diurnal Variation in Height and Associated Surface Contour Changes in Spinal Curves

Height is not a static state. The ‘standing as tall as possible’ heights of 34 females of medium height aged 18–40 were 7–36 mm greater than when they stood as relaxed as possible. All measurements were made with heels on the floor, knees extended and heels, buttocks, back and occiput against the wall. The cervical curve was always, and the lumbar curve usually, straighter with the taller height. Using the same criteria and standing as tall as possible the height on rising could be up to 18 mm greater than later in the day. The decrease in height occurred mainly in the first four hours. Full restitution occurred with a night's rest and partial restitution after relaxation or lighter work.