Metabolic Responses to Exercise DETECTING THE ONSET OF ADDED CARDIOVASCULAR STRAIN DURING COMBINED ARM AND LEG EXERCISE

JERRY J. MAYO, LEN KRAVITZ, AND JATAPORN WONGSATHIKUN. Detecting The Onset Of Added Cardiovascular Strain During Combined Arm And Leg Exercise. JEPonline. 2001;4(3):53-60. The purpose of this study was to determine the preferred distribution of arms to legs during combined arm-leg exercise. Fourteen subjects (7 males, 7 females) completed seven experimental testing sessions: one maximal oxygen consumption (VO2max) test on a cycle ergometer and six submaximal exercise trials at 60% of leg cycling maximal power output (MPO), with total power output (PO) being distributed between the upper and lower body. All combined work incorporated synchronous arm cranking and leg cycling at 50 rev/min using two cycle ergometers. The 7 randomized exercise trials involved combined arm and leg exercise where the arm involvement contributed 0, 8, 17, 25, 33 and 42% of total power output. Heart rate (HR) and oxygen consumption (VO2) were significantly (p<0.05) greater during the 33% and 42% arm trials compared to the 0% arms (leg-only cycling). Trials using 17% and 25% arms elicited significantly lower (p<0.05) blood lactate (BLa) compared to 0% arms. No significant differences were found in respiratory exchange ratio, ratings of perceived exertion or O2 uptake kinetics across conditions. Results of this study suggest that at 60% MPO the preferred ratio of arm to total PO ranged from 17-25% arms. When compared to 0% arms, the 17% and 25% arms trials produced a similar HR response, and slightly higher (non-significant) VO2, and a significantly lower BLa.