Measurement properties of an adapted stadiometric protocol to assess spinal shrinkage: On the use of an optical approach to measure lumbar specific measures.

The cumulative effects of spinal loading can be assessed by measuring spinal shrinkage (change in length) using stadiometry. However, traditional stadiometry protocols only measure total spine shrinkage, and their complex posture control strategies (using sensors and apparatus) require a costly pre-training session. The aim of this study was to test the measurement properties (repeatability, test-retest reliability, concurrent validity, responsiveness) of a simplified protocol, requiring no separate training, also providing lumbar- and thoracic-specific measures. Twenty participants (8 males and 12 females) performed two sessions 3-14 days apart for test-retest reliability testing. Ten successive stadiometric (indicator over the head) and optical measures at four spine levels were performed while standing in a standardized 5-point posture against a wall, before and after both a side-lying unloading and a 10-kg loading condition. The simplified "against-the-wall" repositioning strategy produced repeatable scores. The optical approach gives satisfactory results for concurrent validity, responsiveness, and absolute (but not relative) reliability.