Does centripetal acceleration affect trunk flexion monitoring by means of accelerometers?

Micro electro-mechanical and NANO technologies are sensibly reducing circuit and geometrical errors in accelerometer sensors. These sensors are often used as portable inclinometer sensors for trunk flexion monitoring in clinical applications. In this case, the rotating trunk generates centripetal acceleration, an error source that technological efforts cannot eliminate. This study analysed the effect of this source for typical human monitoring conditions by simulations and clinical validation using a wearable device with rate gyroscopes and accelerometers (Giansanti and Maccioni 2005 Physiol. Meas. 26 689-705). Results showed that this error source did not affect long-term monitoring applications (Mathie et al 2004 Physiol. Meas. 25 R1-R20) but in the short-term monitoring caused a mean angular error equal to 0.96 degrees for the most critical single-task application represented by the sit-to-stand.