IMPORTANT TERMSIMPORTANT CONCEPTSINTRODUCTIONMEASURING MAXIMAL AEROBIC CAPACITYEquation 1:34.142 + (0.133 * AGE) – 0.005 (AGE2) + 11.403 (GENDER) +EXPERIMENTAL PROBLEMPROCEDURECalculationsALL OF THIS DATA SHOULD BE PUT INTO TABLES IN THE RESULTS SECTION OF YOUR LAB REPORT.IMPORTANT TERMS1. Cardiac Output2. Oxygen Delivery3. Oxygen Utilization4. AVDO25. Maximal aerobic power (VO2 max)6. Incremental exercise test7. Ventilatory BreakpointIMPORTANT CONCEPTS1.Max VO2 = HR max * SV max * AVDO2 max (Fick Equation)2. Relationship of VO2, work, and heart rate3. Measurement of VO2maxa. Incremental testb. Prediction testINTRODUCTIONIn the early 1920’s Hill and Lupton reported that each individual has a maximum level of oxygen uptake. The energy required for work to be done above this maximum level is provided by anaerobic metabolism. In the 1950’s Astrand and Taylor developed standard experimental techniques for measuring the maximum oxygen consumption (denoted as VO2 max.). The procedure they developed depends on the progressive relationship between VO2 and work-rate. At a certain point, further increases in the work-rate do not produce any further increases in VO2.VO2 max is generally considered to be the best single physiological indicator of an individual’s ability to sustain dynamic muscular activity and is a measure of aerobic power. Measurement of VO2 max involves a progressive, incremental test performed on an exercise device such as a treadmill or cycle ergometer. The test can either involve work being performed continuously or with rest periods interspersed between exercise bouts (discontinuous test).The two factors that determine VO2 max are the capacity for oxygen delivery and oxygen utilization. Maximum oxygen delivery is a direct function of the oxygen carrying capacity (hemoglobin saturation) and cardiac output (Q), which is the amount of blood pumped by the heart per minute. Cardiac output is dependent on stroke volume (the amount of blood pumped per heartbeat (SV) and heart rate (HR):Q = SV * HROxygen utilization depends on the cellular capabilities of the muscle for aerobic metabolism. These include aerobic enzyme activity, number and size of the mitochondria, muscle perfusion, and capillary density. The difference in oxygen content between arterial and venous blood (AVDO2) reflects themagnitude of oxygen utilization by the muscle. The total oxygen consumption is therefore a product of Q and AVDO2:VO2 = Q * AVDO2Rearranged, this gives:VO2 = HR * SV * AVDO2LABORATORY #3: MAXIMUM OXYGEN CONSUMPTION1During exercise, changes in HR, SV, and AVDO2 account for the changes in oxygen consumption. In most individuals stroke volume reaches maximum levels at approximately 40% of VO2 max. Heart rate and AVDO2 increase throughout the range of exercise intensity and are responsible for VO2 increases throughout incremental exercise.There is much debate over what is the limiting factor for VO2 max. Some researchers report that skeletal muscles are able to use oxygen at a higher rate than what can be met by the cardiovascular and respiratory systems. The current predominant opinion is that the cardiac output is the primary limitation of whole body oxygen consumption.There is a fairly broad range of values for VO2 max depending on such factors as exercise mode, training status, age and gender. Since the whole body uses oxygen, it follows that a larger individual has a greater absolute VO2 max (l/min) than a smaller person both at rest and during exercise. For comparative purposes, VO2 max is usually expressed relative to body mass (ml/kg/min) or relative to lean body mass (ml/kg LBM/min, LBM = body mass – fat mass). When expressed relative to body weight, typical VO2 max values for college age men and women are approximately 48 and 40 ml/kg/min, respectively. Other typical values are represented in Table 1.Table 1:Typical VO2 max values (ml/kg/min)PopulationMalesFemalesCollege Student 48 40Elite distance runner 83 65Sedentary: middle aged adults35 30Post myocardial infarction patients22 18Severe pulmonary disease patients13 13MEASURING MAXIMAL AEROBIC CAPACITYRoutine testing of VO2 max has traditionally been performed on a treadmill or cycle ergometer. Unless specific exercise training has occurred on a particular apparatus, the highest values are found with a treadmill running protocol. This is due primarily to the larger amount of muscle mass working against gravity. Moreover, local muscle fatigue on a cycle or rowing ergometer may force exercise cessation before a participant reaches maximum levels.DIRECT MEASUREMENT: INCREMENTAL EXERCISE TESTSThe VO2 max test is a graded or incremental test of increasing workload. It may be performed continuously or discontinuously with 5-10 minute rest periods between workloads. The length of each workload is about 2-3 minutes to allow steady state to occur, at least for the lower workloads. The participant exercises to the point at which he/she can no longer continue. Psychological factors (motivation)may influence an individual’s effort to achieve a maximum level. The following objective physiological criteria are used to assess whether a true max has been attained:1. A plateauing or decrease in VO2 despite further increases in workload. This is the bestpredictor for attaining a true VO2 max.2. An RER > 1.13. Exercise HR is within 15 bpm of age predicted max HR (220- Age)4. Blood lactate concentration > 70-80 mg/ 100mlThe test is generally accepted as a maximum value if two of the first three criteria are met. If a maximum is not achieved, the value is referred to as peak VO2.During incremental exercise to maximum, increased CO2 and resulting lower pH in the blood acts as a strong ventilatory stimulus causing ventilation rate to rise disproportional to the oxygen uptake response. This ventilatory response results in a deviation from linearity when plotted against workload or VO2. The point of delineation is the ventilatory breakpoint (VBP). This transition typically correlates with increased lactate in the blood and is sometimes used to predict the lactate threshold. Late onset of the ventilatory threshold is a good indication of endurance performance and can be used to ensure a test is at least near maximal.TESTS TO PREDICT MAXIMAL AEROBIC CAPACITYOften it is impossible to directly determine VO2 max because of equipment limitations or time constraints when testing large numbers of people. Also there may be medical or legal problems