Concept 2 Rowing Calories

gearhead426hemi

Just want to finish by saying thanks everyone for the entertainment, some much needed laughing and a reason to wipe the dust off the physics book at work. TR0Roberts, heybales, Azdak, sijomial, BrianSharpe and MeanderingMammal hope you all the best on your fitness journey.


MilesAddie the guy who started this jacked thread. Man just row like there is no tomorrow!!

MilesAddie

Again, Thanks to everyone. Row is posted in the WOD tomorrow.

sijomial

@gearhead426hemi

I'll make the assumption from your user name you know a little about engines so here's an analogy that might make the penny drop....

Engine A produces 300 bhp @ 6000rpm
Engine B produces 150 bhp @ 6000rpm

Engine A is clearly burning more energy to produce double the power but their revs are the same.

The key to the analogy is that:
Engine A is an elite athlete.
Engine B is an ordinary athlete.
Revs is heart rate.

Engine A is taking in double the fuel and double the oxygen to produce double the power (energy).

Just like engines are different so are hearts and CV systems in their entirety.

When I was merely fit my resting HR was 60, now I'm very fit it's dropped by 20% to 48.
You must realise I'm not burning 20% less energy than I used to?

My heart is stronger and has a better flow rate.
I can measurably produce more power at a far lower HR than I used to. I've put a turbo on my engine if you like - "revs" the same but more power.

TR0berts

Something was bothering me about this yesterday, but I couldn't quite put my finger on it. I realized later what it was.

gearhead426hemi wrote: »

Now I am not a physicist but I run a power plant and by my calculations to move 200 pounds at a 8 mile per hour pace takes 580.1475 joules. To move 200 pounds at a 5 mile per hour pace takes 226.6201 joules. Converting joules to calories means it takes 138.56 calories to move 200 pounds at an 8 mile per hour pace and 54.12 calories to move at 5 mile per hour pace. If it requires more calories then it requires more energy which will make your muscles have to work harder which in turn will increase your heart rate.

You're using an equation for kinetic energy of a particle, which isn't applicable to this scenario. This is simply the energy contained at any one point in the 200 lb object while moving. It's also just how much energy is required to move something from rest to that speed. It doesn't amass any more kinetic energy while it's moving at a constant velocity. As such, later, when you tried to apply these values to the object moving 5 miles, it doesn't actually work that way. You need to use the equation W = F*d, which doesn't involve speed.


Additionally, 54 calories = 0.054 kilocalories, while 139 calories = 0.139 kilocalories, so any difference in getting the object moving is negligible anyway - less than 1 Calorie.