For each study, participants completed aerobic running tests on a motorised treadmill (RUNRACE, Technogym, Gambettola, Italy or Woodway ELG 55, Weil am Rhein, Germany) (Chapters IV, V, VI and VII). In Chapter IV only, participants completed an aerobic cycle test on a cycle ergometer (Monark Ergomedic 874E, Vansbro, Sweden). Participants were familiarised with all the exercise equipment prior to completing each test.
53 3.6.1 Sub-maximal incremental treadmill test
Participants were required to complete a sub-maximal incremental treadmill test to determine the relationship between running speed and oxygen consumption. The test was designed such that participants would run continuously at a range of different exercise intensities, but would not be maximal. The test was 16 minutes in duration and consisted of four, four minute stages. The test was completed on a flat running surface (i.e.: 0 % gradient). The initial treadmill speed was between 7 – 9 km·h-1 depending on the participant‟s reported fitness level. The treadmill speed was increased by 1 – 1.5 km·h-1
at the end of each four minute stage. During the final minute of each stage, expired air was collected into Douglas Bags (Plysu Protection Systems, Milton Keynes, U.K.) for determination of oxygen consumption and carbon dioxide production. Heart rate was recorded throughout the test as described in section 3.4 and RPE was recorded as described in section 3.5 during the expired air collection. On completion of the test, running speed at each stage was plotted against oxygen consumption (mL·kg·-1min-1) at that speed to determine the sub-maximal relationship between speed and oxygen consumption.
3.6.2 Maximal oxygen uptake treadmill test
After allowing for sufficient recovery from the sub-maximal test, maximal oxygen uptake was measured directly. Running speed was kept constant whilst treadmill grade was increased by 1 % every minute from a starting gradient of 0 % until volitional fatigue (Jones and Doust 1996). Expired air was collected into Douglas Bags (Plysu Protection Systems, Milton Keynes, U.K.) during the final minute of the test when the participant indicated that they could continue for only one more minute. Heart rate and RPE were recorded throughout the test. On completion of the test, the expired air sample was analysed for oxygen consumption and carbon dioxide production. Once maximal oxygen uptake was determined, using data from the sub-maximal running test it was possible to predict the speed that would elicit the required percentage of maximal oxygen uptake to be used during the main trial treadmill tests.
3.6.3 Sub-maximal incremental cycle ergometer test
In the study in Chapter IV, participants were required to complete a sub-maximal incremental test and maximal oxygen uptake test on a weight basket cycle ergometer as well as on a treadmill (as described previously). The sub-maximal test was 16 minutes in duration consisting of four, four minute stages. Participants pedalled continuously at a
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cadence of 60 rpm with an initial starting mass of 1.5 kg. The applied mass was increased by 0.5 kg at the end of each four minute stage. During the final minute of each stage expired air was collected into Douglas Bags (Plysu Protection Systems, Milton Keynes, U.K.) for the determination of oxygen consumption and carbon dioxide production. Flywheel revolutions were also measured during this time using an electrical revolution counter. Heart rate was recorded throughout the test as described in section 3.4 and RPE was recorded as described in section 3.5 during the expired air collection. Participants were verbally encouraged to keep a constant cadence of 60 rpm to ensure that work rates were common amongst the participants. On completion of the test, the work rate at each stage was calculated using the following equation to determine the relationship between work rate and oxygen consumption:
Work Rate (W) = [Applied mass (kg) x g (m·s-2)] x [Flyhweel circumference (m) x Flywheel revolutions] / Time (seconds)
3.6.4 Maximal oxygen uptake cycle ergometer test
After sufficient recovery, participants completed a maximal oxygen uptake test to exhaustion. Dependent on the ability of the individual, the initial mass applied to the cycle ergometer was between 2 - 4 kg. Participants were encouraged to keep to a pedal cadence of 60 rpm and were instructed to maintain a seated position throughout the test. The test consisted of three minute stages but was continuous in nature with the applied mass being increased by 0.5 kg at the end of each three minute stage. Expired air was collected between 1 minute 45 seconds and 2 minutes 45 seconds of each stage. Flywheel revolutions were also measured during this time using an electrical revolution counter. Heart rate was recorded throughout the test as described in section 3.4 and RPE was recorded as described in section 3.5 during the expired air collection. When the participant indicated that they could continue for only one more minute, a final sample of expired air was collected. At the end of the test, oxygen consumption and carbon dioxide production was determined from the expired air samples. The work rate at each stage was calculated as described in section 3.6.3. Once maximal oxygen uptake was determined, using data from the sub-maximal test, it was possible to calculate the work rate that would elicit the required percentage of maximal oxygen uptake to be used during the main trial cycle ergometer tests. Rearranging the equation in section 3.6.3, the applied mass that needed to
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be added to the cycle ergometer that corresponded to the work rate at the required percentage of maximal oxygen uptake could be calculated.