Repeatability and validity of the combined arm-leg (Cruiser) ergometer

The measurement of physical fitness of lower limb amputees is difficult, as the commonly used ergometer tests have limitations. A combined arm-leg (Cruiser) ergometer might be valuable. The aim of this study was to establish the repeatability and validity of the combined arm-leg (Cruiser) ergometer. Thirty healthy volunteers carried out three incremental exercise tests, once on the bicycle ergometer and twice on the Cruiser ergometer. The repeatability of the Cruiser ergometer was assessed by studying the mean values of the test-retest and the validity by studying the mean values of the bicycle and the two Cruiser ergometer tests. The intraclass correlation coefficient for repeated measurements on the Cruiser ergometer was 0.84 for the maximal oxygen consumption (V(O2max)), and 0.71 for the maximal heart rate (HR(max)). The intraclass correlation coefficient for the measurements on the bicycle ergometer and the Cruiser ergometer was 0.86 for the V(O2max) and 0.73 for HR(max). Bland and Altman plots for V(O2max) and HR(max) showed a bias close to zero and a great accuracy. The conclusion of this study is that the Cruiser ergometer provides a repeatable and valid measurement of physical fitness in healthy volunteers. Its value in clinical practice for lower limb amputees needs to be further established.