METABOLIC AND CARDIAC RESPONSES TO PEDAL ARM CADENCE DURING UPPER BODY EXERCISE IN HEALTHY MALES WITH PARAPLEGIA AND CONTROL SUBJECTS.

Abstract

1375 Cycling cadence has been investigated during lower body exercise testing to establish the most efficient cadence for optimal test performance. The present investigation sought to determine the efficiency associated with two cycling cadences during upper body ergometry in a group of healthy males with paraplegia (P) and age, height and weight matched control subjects (AB). Eight healthy males with paraplegia (T7-L2) and eight able-bodied control subjects with a wide range of peak oxygen consumption (VO2)(2413 ± 541 & 2758 ± 535 ml/min) volunteered to participate in this investigation. Subjects were asked to perform two 12 watt/minute incremental maximal exercise tests in random order at a pedal cadence of either 30 or 60 revolutions per minute (RPM). During these maximal exercise tests oxygen consumption, carbon dioxide production and ventilation (Ve), were measured using a SensorMedics 2900 Metabolic cart. Intravenous arm lactic acid(La) production was measured each minute during the test. Heart rates (Hr) were recorded using a three lead configuration with one electrode placed on the sternum between clavicular bones and one electrode on each thigh approximately an inch above the knee. This configuration was selected to avoid much of the motion artifact produced from torso sway during upper body pedaling. All tests were performed on a Fleisch Universal Upper Body Ergometer in a thermal neutral environment. A multifactorial analysis of covariance model was used to determine differences between the protocols covaried over watts for Hr, VO2, Ve and La. The Hr slope was significantly steeper for the 30 vs. the 60 RPM protocol (0.644 ± 0.034 Vs. 0.561 ± 0.022; p < 0.05). The VO2 slope was also significantly steeper for the 30 compared with the 60 RPM protocol (15.09 ± 0.713 Vs. 13.44± 0.37; p < 0.05). No significant differences were found for Ve or La slope comparing the two protocols. The metabolic efficiency associated with exercise testing is crucial to the manifestation of a true maximal effort. During upper body ergometry, these results indicate that the 60 RPM protocol was significantly more efficient compared with the 30 RPM protocol.