Posted On: Tuesday - October 15th 2019 5:24PM MST
In Topics:   Artificial Stupidity  Science
Exercise machines have been somewhat of a sub-fixation within Peak Stupidity's topic key called Artificial Stupidity. Though we did mention the mechanical quality (or lack thereof) of one of the machines, in relation to the subject of Cheap China-made Crap, our problem has been with the much easier to fix (or do right the first time) matter of the displays.
We discussed some more force-feeding of TV (without some extra effort!) on one of the bike machines recently, mostly our beef has been with the lack of accurate and/or meaningful calculations of the data presented. In fact, in that post on the Sears one with the quality problem, titled "The
The sometimes simple (on the bike machines) and often more complicated physical calculations required to give accurate displays of exercise being accomplished were discussed here in "Peak Torque, Wattage, and Exercise Machine electronic stupidity". There can be a lot to it, but, as I've written before, in an open sentence* to these exercise machine manufacturers, for cryin' out loud, just hire a 2nd-year physics or mechanical engineering student of a few hours to give you the formulae for your geeks to program in! WTF is so hard or expensive about that, spread out over a few or tens of thousands of units?
That all said as a long-winded intro, or summary, however you take it, the reason this post DOESN'T HAVE the curmudgeonry tag is that I used a treadmill that did seem to be programmed to display work done correctly. This was a Bowflex machine, the company more known for the workout tools using flexing members. Well, they done good here. There's a cool speedometer-type gauge that reads in calories/min (burned). It read close to linear with speed. Keep in mind, or peruse that post on Peak Torque ... etc, that no, that's not all there is to it. This value does depend on the user's weight, but also, muscle type and other things that can't be known, much less calculated in. (Other machines do let you input your weight - this may or may not - I didn't notice.)
Now, the linearity of displayed work done with speed is probably the case for other treadmills, for the most part. The bigger deal with this Bowflex is that as I moved the incline up and down to experiment, calories/min varied linearly with incline too. That is important. After all, just based on pure rigid-body physics, the power being exerted should be ZERO at the horizontal setting**. The vertical speed, a pretty linear function of incline at the settings of these treadmills(no more than 15% for most of them), should have a linear relationship with the rate of calorie burn. Most of the other machines I've seen DO NOT calculate it this way. Their displays of calories are totally bogus for that reason, if one uses the incline feature.
The display on the Bowflex was otherwise kind of boring, with no track or Go-Pro camera footage, but that's OK. The numbers are right, or if not right, they vary as they should with your speed and incline. This means that you can be rewarded with the right numbers for the extra effort you put in. I even tested the thing at a high speed that I could not possibly keep up with, and the needle pegged. Even better, the read-out told me "you've pegged out!" Well, I wasn't actually on the machine, but I like that old-timey terminology.
Nice job, Bowflex. If I'm gonna review this machine, I may as well state that it is not as massive as many of the other brand treadmills, the Precors and such. Whether it would last as long is something I can't say. For home use, hopefully, it would do OK, and being lighter, at least one could possibly move it into the house. As far as the display and accurate calculations go it's Bowflex for the win!
* Can you do that, write just an "open sentence" instead of a long-ass "open letter" to people? Do they read it?
** WHAT?! See, that's why there's more to it. One most certainly is exercising like hell at 10 mph even with the belt level. Using the definition of mechanical work as Force -dot- distance (power = Force -dot- speed) well, the power is the weight force (g x mass, or your weight) times your vertical speed component, the latter easily calculated by belt speed x sin(incline ANGLE, not SLOPE).
So, what does this mean? It means that the work done by your muscles moving your mass around, up and down, and sideways, is exertion of energy. The amount is not easy to calculate, but a linear relationship with speed is quite reasonable.