We use our Body-Solid home gym regularly. My workout takes about 20 minutes with pauses between routines. Today. I didn’t pause. Workout time was 15 minutes, or 900 seconds.
A principle of physics I taught about involved work, energy, and power. I wondered how much work was done lifting the weights during my workout. Each routine raised the weight different amounts. Units used are Newtons of force and meters of distance. 1 N-m = 1 Joule of work.
Work done = Newtons x distance x number of reps
Total work done was the sum of the separate routines equal to 20,900 Joules.
Average power generated, or work per second, equals 23 Joules/sec, or 23 Watts.
If I just sit around and do nothing, my body utilizes energy at a rate of about 81 Joules/sec, or 81 Watts. It is calculated from the Metabolic Equivalent expression of 1.162 Watts/kg. I multiplied my 70 kg x 1.162 Watts/kg to get 81 Watts.
Other physical activities are scaled with reference to this figure. For example, earlier I went for a walk at a brisk pace of 3.4 mph for about 30 minutes. According to the tables, energy was utilized by my body at a rate 3.6 times the metabolic equivalent, or 81 x 3.6 = 292 Watts. Bicycle racers can generate 500 Watts for hours at a time. If a level of 746 Watts is reached, it is also known as one horsepower.
You can look up many activities at the Compendium of Physical Activites. They include things like bicycling, dancing, sexual activity, lawn mowing, etc. Each is rated with a Metabolic Equivalent score. Take your body mass in kg x 1.162 x the score in the activity.
Melanie said “Be sure to provide a link to your post about mowing the lawn.” Thank you, dear.