Of many approaches to reduce motion analysis errors, the compensation method of anatomical landmarks estimates the position of anatomical landmarks during motion. The method models the position of anatomical landmarks with joint angle or skin marker displacement using the data of the so-called dynamic calibration in which anatomical landmark positions are calibrated in ad hoc motions. Then the anatomical landmark positions are calibrated in target motions using the model. This study applies the compensation methods with joint angle and skin marker displacement to three lower extremity motions (walking, sit-to-stand/ stand-to-sit, and step up/down) in ten healthy males and compares their performance. To compare the performance of the methods, two sets of kinematic variables were calculated using different two marker clusters, and the difference was obtained. Results showed that the compensation method with skin marker displacement had less differences by 30~60% compared to without compensation. And, it had significantly less difference in some kinematic variables (7 of 18) by 25~40% compared to the compensa- tion method with joint angle. This study supports that compensation with skin marker displacement reduced the motion analysis STA errors more reliably than with joint angle in lower extremity motion analysis.

The purpose of this study was to examine inter- and intra-examiner reliability of the sacroiliac joint (SIJ) anatomical landmarks palpation. Two physical therapists and one doctor specializing in rehabilitation examined 22 asymptomatic subjects. They examined anterior superior iliac supine (ASIS), posterior superior iliac supine (PSIS) and iliac crest (IC). For the assessment of intra-examiner reliability, 3 examiners repeated the measurements 3 times over a 2-week interval. Kappa (Kg) yielded intra-examiner reliability that ranged between slight to fair for the ASIS (Kg=.06 to .26; mean Kg=.19), and slight for the PSIS(Kg=-.04 to .18; mean Kg=.07) and slight to fair for the IC (Kg=.06 to .32; mean Kg=.21). Inter-examiner reliability was slight (ASIS Kg=.13; PSIS Kg=.05; IC Kg=.14). These results suggest that the reliability of the assessing SIJ anatomical landmarks using palpation and observation as an indication of SIJ dysfunction still remains questionable. Before this test can be relied upon as an accurate indicator of SIJ dysfunction, it must undergo further research. This further research needs to examine not only reliability, but also validity, sensitivity and specificity.