Cardiovascular tests during a self-paced maximal exercise protocol (SPV) continually scored high ratings of VO2 max when compared to more traditional procedures. Jenkins et. al sought to understand the underlying causes of this increase in VO2 max by testing SPV versus the more regimented RAMP method. They sought to explore the results through extensive physiological measurement, as well as testing difference in older and younger age groups, while participants completed physical experiments.
The SPV protocol was completed on an air-braked cycle ergometer, which allowed participants to continually vary their Power Output (PO) throughout the test. An electro-magnetically braked cycle ergometer was used for the RAMP protocol, so that PO was fixed for each stage of the incremental RAMP protocol.
VO2 Max is essentially the maximum amount of oxygen utilized during a workout. Forty-four (44) male and female participants completed the experiment, half aged between 18- 30 and half between 50-75. The participants completed each test over a multi-day period. The tests were exhaustive, requiring subjects to cycle in place until they couldn’t any longer.
Jenkins et. al recorded various physiological signals including NIRS, breathing/expired gases, cardiac output/ stroke volume, blood lactate, and electromyography (EMG). BIOPAC’s BioNomadix research acquisition system wirelessly transmitted EMG data using two electrodes placed on participants’ right leg while they completed physical tasks.
Researchers were able find differences in the interaction effects of EMG between the two test protocols in the older group. The results complied with previous research, in that SPV allowed a higher VO2 max compared RAMP. Through monitoring physiological measurement, the study results suggested increased oxygen delivery as to an increase in oxygen-muscle extraction. The researchers found that there wasn’t a significance difference between the two testing protocols with the older population, though it’s unclear why. Overall, the experiment provides greater understanding of what causes differences in VO2 max between the two experimental procedures.
