1a. Why are running tests to estimate VO2 max usually done for 12 min or so for
ID: 3510137 • Letter: 1
Question
1a.
Why are running tests to estimate VO2 max usually done for 12 min or so for adults? What would happen to the estimated VO2 max value if an all-out 3 min run test were used?
1b. You've been working with Tom for six months now, most recently with an intermittent walking and jogging program. You now want to recommend that Tom run/jog continuously at an intensity of 9 METs for at least 45 minutes, 5 days per week. At what speed should Tom run when on an horizontal surface? If Tom runs on the walking path near his house (up a 3% grade), how would you modify his running speed in order to maintain an exercise intensity of 9 METs?
Explanation / Answer
1a. The oxygen uptake is increased as the running speed increases. When a person runs/jogs, initially anaerobic energy, that is the energy from the short-term or immediate energy sources is consumed. If VO2 max is estimated for 5 to 6 minutes or when anaerobic energy contributes significantly to the overall energy, the resultant VO2 max will be overestimated. So the test has to be long enough to nullify the effect of anaerobic energy. On the other hand, if the person runs for a long time, the VO2 max will be underestimated. Thus, running or jogging for 12 minutes provide optimum measurement of VO2 max.
1b. Metabolic equivalents (METs) = 9; Grade = 3% = 0.03;
VO2 = METs * 3.5 = 9*3.5 = 31.5
VO2 = 31.5 ml/kg.min
Speed at horizontal surface:
VO2 = (0.1 * speed) + 3.5
=> 31.5 = (0.1 * speed) +3.5
=> Speed = (31.5 - 3.5) / 0.1 = 280 m/min
Speed at horizontal surface = 280 m/min
Speed at 3% grade surface:
VO2 = (grade * Speed* 1.8) + (0.1 * Speed) + 3.5
31.5 = (0.03*Speed*1.8) + (0.1 * Speed) + 3.5
28 = (0.054*Speed) + (0.1*Speed)
28 = 0.154 * Speed
Speed = 181.82 m/min
Speed at 3% grade surface = 181.82 m/min
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