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The purpose of this investigation was to assess the accuracy of the COSMED K4 b2 portable metabolic measurement system against the criterion Douglas bag (DB) method. During cycle ergometry on consecutive days, oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), and respiratory exchange ratio (R) were measured at rest and during power outputs of 50, 100, 150, 200, and 250W. No significant differences (P > 0.05) were observed in VO2 between the K4 b2 and DB at rest and at 250W. Though the K4 b2 values were significantly higher (P<0.05) than DB values at 50, 100, 150, and 200 W, the magnitude of these differences was small (0.088, 0.092, 0.096, and 0.088 L x min(-1), respectively). VCO2 and VE values from the K4 b2 were significantly lower than the DB at 200 and 250 W, while no significant differences were observed from rest through 150W. The slight overestimation of VO2 (50-200 W) combined with the underestimation of VCO2 (200 and 250W) by the K4 b2 resulted in significantly lower R values at every stage. These findings suggest the COSMED K4 b2 portable metabolic measurement system is acceptable for measuring oxygen uptake over a fairly wide range of exercise intensities.

The purpose of this study was to test the validity of the Aerosport KB1-C portable metabolic measurement system against the criterion Douglas bag method. During cycle ergometry, simultaneous measurements of minute ventilation (VE), oxygen consumption (VO2), and carbon dioxide production (VCO2) were made at rest and at power outputs of 50, 100, 150, 200, and 250 W. No significant differences (P > 0.05) were observed for VE, VO2, and VCO2 between the KB1-C and Douglas bag at 100, 150, and 250 W, while the KB1-C was significantly different (P < 0.05) from Douglas bag values at rest, 50, and 200 W. R values were found to be significantly different (P < 0.05) at 100, 150, and 200 W, while no significant differences were observed at rest, 50, and 250 W. The fractional concentrations of oxygen (FEO2) and carbon dioxide (FECO2) were not significantly different at 50, 100, 200, and 250 W while values at rest and 150 W were significantly different (P < 0.05). These findings show that the Aerosport KB1-C portable metabolic system is acceptable for measuring oxygen uptake in the range of 1.5 and 3.5 L x min(-1), using the medium flow pneumotach setting. At lower intensities, the low-flow pneumotach setting provides acceptable results.

Polylactate (PL), a semi-soluble amino acid/lactate salt, is a newly developed carbohydrate supplement purported to increase endurance. Our purpose was to determine if the addition of PL to a glucose polymer solution (GP) extends exercise time relative to a pure GP solution. In a double blind and random crossover design, 5 subjects exercised twice to exhaustion at 70% of VO2max. During the trials, they consumed GP or a GP/PL mixture at the rate of 0.3 g carbohydrate per kg of body wt in a 7% solution every 20 min until exhaustion. The GP/PL mixture contained 6.25 g GP to 0.75 g PL per 100 ml of water. Mixture composition was critical because PL, as supplied by the manufacturer and under our experimental conditions, produced severe gastro-intestinal efflux in concentrations > or = 2.5%; PL was tolerable in concentrations < or = 0.75%. At 20 min intervals, we measured VO2, respiratory exchange ratio, heart rate, and perceived exertion. At 30 min intervals, we measured serum glucose, insulin, free fatty acids, and glycerol as well as whole blood lactate and pH. We found that the addition of PL to a GP solution had no measurable physiological or performance effects.

The purpose of this study was to examine the effect of moderate resistance weight training (MRWT) on peak arm aerobic power as measured by arm cranking ergometry. Fourteen sedentary college age males, divided equally into two groups, served as subjects. The seven subjects in the MRWT group completed 12, 1-hr bouts of weight lifting over a 4 week period, exercising on Monday, Wednesday and Friday of each week. Exercise sessions included 3 sets of 10 repetitions of the following lifts: bench press, overhead dumbbell press, dumbbell arm curl, and behind the neck pull down. The remaining seven subjects served as a non-training control group, whose purpose was to account for possible learning effects on the arm ergometer test that could distort the statistical relevance of the aerobic power data. These subjects did not serve as a control for the weight training exercises, as the procedures used to determine muscular strength may produce a modest training effect. Peak arm aerobic power and muscular strength, as measured by the one-repetition maximum for each lift, were determined before and after the training program. The average increase in strength for all lifts combined for the trained group was 20.0%. They also experienced a 13.4% (p < .005) increase in peak arm aerobic power, whereas there was no significant change in this variable for the control group. It is concluded that peak arm aerobic power is enhanced by the changes in muscular strength produced by 4 wks of MRWT.