Determine the MET level for each activity for a 70 kg person.
a.) 18 steps/min, 25 cm/step
b.) 6 mph, 12% grade
c.) 750 kg m/m on a Monarch ergometer
d.) Arm cranking at 350 kg m/min on a Monarch ergometer
To determine the MET level for each activity, we need to analyze the intensity of the activity and compare it to the resting metabolic rate. MET stands for Metabolic Equivalent of Task, which is a unit used to estimate the energy expenditure of physical activities.
The resting metabolic rate (RMR) is the amount of energy the body needs at rest. It is generally defined as 1 MET. For a 70 kg person, the RMR is approximately 1,670 kcal/day or 1 MET.
Let's calculate the MET level for each activity:
a.) 18 steps/min, 25 cm/step:
To calculate the MET level, we need to determine the energy expended during this activity compared to the RMR.
Step 1: Calculate the energy expenditure per minute:
Number of steps per minute x Step height x body weight in kg
18 steps/min x 25 cm/step x 70 kg = 31,500 kgcm/min
Step 2: Convert kgcm/min to METs:
Divide the energy expenditure per minute (in kgcm/min) by 350:
31,500 kgcm/min / 350 = 90 METs
b.) 6 mph, 12% grade:
To calculate the MET level for this activity, we need to consider both the speed and the grade of the incline.
Step 1: Convert mph to meters per minute:
6 mph x 1609.34 m/mile / 60 min = 160.934 m/min
Step 2: Calculate the energy expenditure per minute:
Speed (m/min) x body weight in kg x grade (as a decimal)
160.934 m/min x 70 kg x 0.12 = 1,346.05 kgm/min
Step 3: Convert kgm/min to METs:
Divide the energy expenditure per minute (in kgm/min) by 300:
1,346.05 kgm/min / 300 = 4.49 METs
c.) 750 kgm/m on a Monarch ergometer:
In this case, we are given the energy expenditure directly in kgm/m, which makes the calculation simpler.
Step 1: Convert kgm/m to METs:
Divide the energy expenditure (in kgm/m) by 200:
750 kgm/m / 200 = 3.75 METs
d.) Arm cranking at 350 kgm/min on a Monarch ergometer:
Similar to the previous case, we are given the energy expenditure directly in kgm/min.
Step 1: Convert kgm/min to METs:
Divide the energy expenditure (in kgm/min) by 250:
350 kgm/min / 250 = 1.4 METs
So, the MET level for each activity is as follows:
a.) 90 METs
b.) 4.49 METs
c.) 3.75 METs
d.) 1.4 METs