Confusion about watts applied at peddals on a bike & power meters & generated W. - Page 1
Forum section: electronics / beginners

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 02:43:57 am
content: Ok, I would like to know if I properly understand Watts applied at pedals, measurement and power generation.Assuming I have a frictionless mechanical stationary bike wired to a perfect 100% efficient generator, with a measured load and a secondary set of power measurement pedals like these:https://www.powertap.com/page/pedalsIssue #1, if I pedal on my bike powering a perfect 250 watt lamp exactly at 100% on my generator for an hour perfectly, can I say I generated a true 250 watt hours?Issue #2, if I pedal on my bike powering a perfect 250 watt lamp exactly at 100% on my generator for 30 minutes perfectly, can I say I generated a true 125 watt hours?Issue #3, assuming the powertap pedals at 100% accurate & I'm pedaling perfectly, in issue #1, will their log say I generated a total of 250 watts after 1 hour? (Remember, this is not a real world scenario, my generator & bike pedals bearings & gears are frictionless, 100% efficient...)Issue #4, will everything hold true for a 30 minute ride, totaling 125 watts hours?Issue #5, if I pedal powering a 150 watt lamp perfectly for 2 hours non stop, can I say I generated 300 watts hours?Last issue, Can I say that the output of my legs are creating this total power?

author: IanB
author_rank: Super Contributor
timestamp: May 20, 2017, 02:48:34 am
content: Quote from: BrianHG on May 20, 2017, 02:43:57 amNo, this will be 250 watt-hours.QuoteThis will be 125 watt-hours.QuoteAs before, 300 watt-hours.Generally speaking, nothing is perfectly efficient. So if you lit a 250 watt lamp for one hour, you would necessarily have generatedmorethan 250 watt-hours at the pedals.

author: amspire
author_rank: Super Contributor
timestamp: May 20, 2017, 03:03:06 am
content: Quote from: IanB on May 20, 2017, 02:48:34 amI assume you meant 62.5 watt-hours if BrianHG meant averaging 125 watts instead of totalling 125 watts. "totalling 125 watts" doesn't make much sense except in the sense "the right leg was generating at 60W and the left leg was generating at 65W and so the total power I was generating was 125W".Back to the original post, if you generate a measured amount of watt-hours using your legs, you can definitely say you have generated that much energy. IanB is right in saying that you have actually used up a fair bit more energy then that. 1 watt-hour = 3.6kJ = 0.86 food calories (as opposed to the other types of calories that are completely different).

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 03:17:10 am
content: Yes, with issue #4, I meant to say that I was powering the 250 watt lamp at 100% for only 30 minutes, meaning that I generated only 125 watt-hour. Obviously that power is also divided between my 2 legs with an approximate 50/50 balance...

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 03:28:17 am
content: Quote from: amspire on May 20, 2017, 03:03:06 amNow, you are saying, assuming the hardware is impossibly perfect, that, (seems obvious to me, but am I wrong?) that my muscles are not 100% efficient converting food calories to torque as well, + the calories burned for all the additional life support within my body to keep this all metabolic activity going. So for each 1 watt-hour, I am burning a lot more than 0.86 food calories. I also assume that as I approach my peak output, that this food burning calorie efficiency slightly lowers as well?

author: IanB
author_rank: Super Contributor
timestamp: May 20, 2017, 04:11:39 am
content: If you start talking about the efficiency of the muscles in your body, it gets complicated and you will need to talk to the right kind of expert (a physiologist?).When you consume food, it is digested and turned something the body can store for future use (glycogen? fat?). This process has inefficiencies, so to start with you don't get to store all the calories you eat.Secondly, when you do exercise the stored fuel is burned up in your muscles to produce mechanical work, and this also is inefficient. (This is why you get hot and sweaty when you exercise. A lot of waste heat is produced.)So every question like this depends on where you measure the "in" and where you measure the "out". For a pedal cycle machine, you would probably start the measurement with the mechanical power produced by your legs and go from there. This means for sure that every joule of mechanical energy you produce you will need to consume more than one joule of raw energy in your food. Probably much more.

author: amspire
author_rank: Super Contributor
timestamp: May 20, 2017, 04:13:35 am
content: Quote from: BrianHG on May 20, 2017, 03:28:17 amYes. Say you want to loose 10kg of fat, that is 37MJ. If you cycle at 100 watts for 100 hours without eating anything, you will loose at least 10kg. You would probably loose a lot of protein from muscles and organs in your body as well and your health would be pretty crook.

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 04:17:23 am
content: Quote from: amspire on May 20, 2017, 04:13:35 am100 hours non-stop @ 100wattsI'll also be dead...let alone what would happen to my lower back....

author: IanB
author_rank: Super Contributor
timestamp: May 20, 2017, 04:18:04 am
content: Quote from: amspire on May 20, 2017, 04:13:35 amThat sounds like an interesting experiment. So if I purchase an exercise bike and pedal hard on it for 10 hours a day without consuming anything except water (and electrolytes...) I will manage to lose a lot of weight?But I wonder if I might collapse from exhaustion before the 10 days were up...?(Edit: someone beat me to it.)

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 04:25:34 am
content: Example: (Watts should read Watt-hour)Code:Date_Time of workout Time on bike Watts Weight %BF08-16-2016_16h06m20s 0:40:00.7 37.80 201.0 27.008-18-2016_09h06m43s 0:38:40.9 36.62 199.0 26.508-19-2016_13h33m59s 0:38:49.9 36.32 197.0 27.008-20-2016_12h01m20s 0:38:26.4 36.56 199.5 26.508-21-2016_15h29m34s 0:38:40.6 36.55 197.5 26.008-25-2016_08h32m11s 0:38:51.7 36.46 201.5 27.008-26-2016_10h25m39s 0:38:58.5 36.98 200.5 27.008-27-2016_12h41m51s 0:38:35.5 37.14 199.0 27.008-28-2016_12h13m16s 0:38:21.2 37.61 199.5 26.508-29-2016_11h29m39s 0:38:38.6 38.35 200.0 27.008-30-2016_13h08m40s 0:38:32.9 38.91 201.5 27.509-01-2016_12h18m15s 0:38:42.4 38.73 204.0 26.509-02-2016_11h29m30s 0:38:51.9 40.35 203.0 27.009-03-2016_12h34m49s 0:38:57.5 39.86 202.0 27.509-04-2016_13h51m22s 0:38:47.1 39.51 201.5 26.5Break time....09-19-2016_16h18m52s 0:26:43.6 24.49 199.0 26.009-21-2016_14h52m09s 0:33:27.2 30.51 196.0 27.009-23-2016_11h47m19s 0:38:59.8 38.67 197.0 27.009-25-2016_14h40m18s 0:38:26.3 38.69 198.0 26.509-27-2016_14h39m04s 0:38:33.5 37.71 198.0 27.009-29-2016_15h34m47s 0:38:30.2 37.65 197.5 26.510-01-2016_18h45m44s 0:38:33.4 37.71 198.0 26.510-03-2016_21h36m57s 0:38:28.8 38.06 200.0 26.010-05-2016_15h33m48s 0:38:28.7 37.53 198.0 26.010-07-2016_13h45m33s 0:38:44.3 37.78 197.5 27.010-09-2016_18h22m38s 0:38:43.0 39.53 196.5 26.010-11-2016_10h56m09s 0:38:59.0 38.83 198.5 26.510-13-2016_11h02m00s 0:38:28.7 38.48 198.0 26.010-15-2016_14h18m54s 0:38:35.7 39.05 197.0 27.510-16-2016_13h57m33s 0:38:37.8 38.82 197.5 28.510-17-2016_14h21m04s 0:38:34.4 38.51 196.0 28.010-20-2016_16h21m11s 0:38:43.5 39.30 195.5 27.510-22-2016_16h28m40s 0:38:41.7 39.96 195.0 28.010-24-2016_16h28m09s 0:38:28.4 39.91 195.5 26.510-26-2016_17h52m53s 0:39:00.6 41.25 195.5 27.510-28-2016_14h15m45s 0:38:38.7 40.82 196.5 27.510-30-2016_19h49m29s 0:38:56.9 41.34 196.5 27.511-01-2016_18h11m32s 0:38:49.5 41.68 196.0 27.511-03-2016_18h59m21s 0:38:37.1 40.36 195.5 26.511-05-2016_19h29m46s 0:38:41.9 40.83 195.5 26.511-07-2016_19h34m24s 0:38:42.6 40.10 195.5 28.011-09-2016_18h05m49s 0:38:44.6 39.90 196.5 27.5Increased workout time to 54min.11-11-2016_21h48m29s 0:54:36.9 57.09 194.5 27.511-13-2016_19h02m03s 0:55:15.3 58.47 194.5 27.011-15-2016_18h31m51s 0:54:56.7 56.67 195.0 28.011-17-2016_17h17m42s 0:54:47.8 57.47 195.5 26.011-19-2016_18h48m29s 0:54:40.3 56.72 194.5 26.511-21-2016_23h22m25s 0:55:10.4 58.58 192.5 28.011-23-2016_10h53m15s 0:54:58.8 58.82 195.5 27.511-25-2016_23h10m36s 0:54:43.9 58.35 192.0 26.511-27-2016_13h59m15s 0:54:53.3 58.69 193.0 28.511-29-2016_09h59m52s 0:54:40.1 58.81 193.0 27.012-01-2016_14h06m18s 0:54:56.1 58.67 195.5 27.012-04-2016_11h17m25s 0:54:49.7 58.43 192.5 25.012-05-2016_15h04m05s 0:54:58.6 58.18 193.5 26.512-07-2016_14h12m02s 0:54:42.9 56.87 190.0 26.512-09-2016_11h58m22s 0:54:48.6 58.19 190.0 25.012-11-2016_13h16m45s 0:54:44.4 58.48 193.5 26.012-13-2016_12h20m55s 0:55:01.2 59.43 193.0 25.512-15-2016_14h23m28s 0:54:38.8 59.86 193.0 22.512-17-2016_15h56m45s 0:54:48.3 60.49 192.0 26.012-19-2016_14h40m34s 0:54:41.4 60.73 192.0 24.512-21-2016_16h26m15s 0:54:41.8 61.20 190.5 25.512-23-2016_23h54m09s 0:54:51.9 60.53 192.0 25.012-25-2016_21h20m04s 0:54:39.4 60.49 190.0 25.512-27-2016_18h14m25s 0:54:54.4 60.12 190.0 25.012-30-2016_02h10m40s 0:54:36.3 61.50 194.0 26.512-31-2016_23h03m59s 0:54:38.0 60.83 191.5 25.001-03-2017_00h09m24s 0:54:39.1 61.18 190.5 25.001-04-2017_23h56m14s 0:54:32.9 61.09 190.5 25.501-07-2017_07h10m34s 0:54:39.3 61.24 190.0 25.501-09-2017_04h32m19s 0:54:43.7 62.08 188.5 22.001-11-2017_04h01m12s 0:54:34.5 61.87 189.0 25.001-13-2017_06h05m55s 0:54:43.5 61.70 189.5 24.001-15-2017_08h24m50s 0:55:11.4 62.46 189.0 24.501-17-2017_09h18m08s 0:54:49.3 62.45 188.0 24.001-19-2017_09h56m37s 0:54:31.3 60.24 188.0 25.001-21-2017_11h55m20s 0:54:36.5 61.84 188.0 23.501-23-2017_14h10m21s 0:54:35.6 62.37 187.5 23.501-25-2017_14h43m26s 0:54:34.9 62.73 187.0 23.501-27-2017_15h02m19s 0:54:35.7 63.31 186.5 24.001-29-2017_18h43m35s 0:54:29.1 63.09 187.5 24.501-31-2017_14h02m05s 0:54:36.0 62.66 185.5 23.002-02-2017_15h56m56s 0:54:34.8 63.09 185.5 23.002-04-2017_18h24m31s 0:54:25.9 62.56 185.5 23.0logs\BikeBrake_02-04-2017_18h24m31s.raw 0:54:25.9 62.56 <<< Com glitch02-05-2017_14h42m47s 0:16:30.7 17.84 <<< Test after cleaning controller board & spraying some contact cleaner into the motor/generator02-06-2017_18h40m13s 0:54:34.1 63.44 186.0 24.502-08-2017_16h25m27s 0:54:25.1 60.69 184.5 23.002-10-2017_15h53m06s 0:54:27.5 63.63 184.0 23.502-12-2017_15h35m29s 0:54:23.7 63.52 185.0 23.502-14-2017_14h53m47s 0:54:28.8 63.58 185.0 23.002-16-2017_16h14m57s 0:54:44.4 63.54 185.0 23.002-18-2017_16h50m11s 0:54:29.0 63.58 183.5 22.502-20-2017_17h22m59s 0:54:34.8 63.31 182.5 22.502-22-2017_16h16m00s 0:54:26.0 63.40 182.5 22.502-24-2017_20h35m35s 0:54:36.5 64.26 182.0 22.502-26-2017_20h01m15s 0:54:32.6 63.54 182.5 22.502-28-2017_21h55m49s 0:54:25.6 63.13 180.0 22.003-02-2017_21h06m41s 0:54:37.2 63.99 182.0 22.503-05-2017_02h45m28s 0:54:32.6 64.25 181.5 22.003-06-2017_21h12m22s 0:54:26.9 63.98 182.5 22.503-08-2017_20h30m21s 0:54:24.3 64.34 181.5 22.503-10-2017_21h07m27s 0:54:37.4 65.14 182.0 22.003-13-2017_02h39m38s 0:46:54.8 52.49 180.5 22.5 >>> back acting up...03-14-2017_11h27m45s 0:54:24.6 61.79 182.0 22.503-16-2017_13h59m05s 0:54:29.4 62.78 180.5 22.503-18-2017_16h09m34s 0:54:25.7 62.87 180.0 22.003-20-2017_12h21m05s 0:54:37.6 63.25 181.0 21.503-22-2017_13h58m17s 0:54:41.1 63.46 181.0 22.003-24-2017_14h03m02s 0:54:45.6 63.11 179.0 21.503-26-2017_14h43m43s 0:54:23.3 63.02 180.0 22.003-28-2017_15h04m40s 0:54:27.7 63.44 180.0 22.003-30-2017_16h42m30s 0:54:26.9 63.06 178.5 21.504-01-2017_16h43m58s 0:54:47.6 63.61 179.0 22.004-03-2017_16h19m30s 0:54:28.3 62.68 180.5 21.504-05-2017_16h50m42s 0:54:36.0 63.58 181.0 21.504-07-2017_18h01m32s 0:54:29.6 63.41 179.5 22.004-09-2017_18h34m46s 0:54:39.2 63.20 178.5 22.004-11-2017_20h31m04s 0:54:31.6 62.99 179.0 22.004-13-2017_18h04m16s 0:54:54.7 64.64 178.5 22.004-15-2017_20h36m46s 0:54:48.5 63.62 177.5 20.504-17-2017_18h15m13s 0:54:41.0 64.50 178.5 21.504-19-2017_20h51m48s 0:54:15.2 62.71 177.5 20.5 Oil on the motor brushes lowered resistance increasing # of Watts/rpm04-21-2017_21h25m33s 0:54:30.6 66.55 177.5 21.004-23-2017_18h27m06s 0:54:58.1 66.26 176.0 20.504-25-2017_20h19m07s 0:54:40.1 64.28 176.0 20.504-27-2017_13h12m42s 0:54:28.6 63.29 176.0 21.504-29-2017_21h11m11s 0:54:37.5 63.80 175.0 20.0 (I double checked, this is the right reading...)05-01-2017_20h06m21s 0:54:20.0 64.24 175.0 20.005-03-2017_22h24m56s 0:54:31.7 63.52 175.0 23.005-05-2017_22h02m37s 0:54:26.6 64.70 176.5 20.005-07-2017_22h46m53s 0:54:42.5 64.56 176.0 20.505-09-2017_17h21m01s 0:54:22.1 63.45 177.0 21.005-11-2017_14h21m31s 0:54:38.8 62.51 174.5 19.0 Double checked, it's correct. And, my back is giving me problems.05-13-2017_13h04m08s 0:54:26.2 63.28 175.0 19.505-15-2017_16h15m12s 0:54:30.3 62.82 177.0 20.0 Slowing down a watt or 2 for my back...05-17-2017_10h21m10s 0:54:24.8 63.15 177.0 19.505-19-2017_12h51m27s 0:54:32.5 63.37 178.0 19.0Note that the efficiency of my stationary bike is at around 33%, running a 125v treadmill motor as generator way down at a low RPM, 15v and damaged brushes. I'll know the real wattage this winter when I can afford to purchase the Powertap pedals to correct my readings.It took me 8 months to loose a true 25 pounds and 7% body fat...Going back the year before, before my back injury, I went from 240 to 200 pedaling 90 watt-hour over a 1hour 12 min workout every third day. (My most productive weight loss year)Over 2 years before going from around 280 to 240 pounds. and over 40% body fat...

author: amspire
author_rank: Super Contributor
timestamp: May 20, 2017, 04:25:57 am
content: If you are just being alive and doing the odd bit of moving around, you are probably already using about 100W of power. Perhaps even walk sometimes.One of the most stupid ideas around is the idea that weight loss is a matter of "calories in-calories out".If you were a battery, it would make sense, but you are not. Some people can eat massive calories and not get fat. If others try and reduce the food too low, their body can go into starvation mode and start consuming the body's protein even though they may be overweight. The goal is to find a way to loose weight without loosing your health. In many overweight people, the body seems to be trying to regulate their weight to that overweight number, and for those people, lasting weight loss can be very difficult.

author: orin
author_rank: Frequent Contributor
timestamp: May 20, 2017, 07:59:16 am
content: Quote from: IanB on May 20, 2017, 04:18:04 amNo, you'd either give up or die of boredom before the end of the first hour. I can't stand riding a stationary bicycle for more than say half an hour every ten years or so.Though I do bike commute a couple of times a week at an average power of not enough for an average time of too long...

author: Cerebus
author_rank: Super Contributor
timestamp: May 20, 2017, 10:35:33 am
content: Quote from: BrianHG on May 20, 2017, 03:28:17 amTalking about a road bicycle the machinery can approach efficiency levels that would look impossible for any other machine built by man. The mechanical efficiency of a modern well-maintained road bike is in the high 90's, 98-99% isn't impossible. Even a poorly maintained bone-rattler probably doesn't dip much below 90% mechanical efficiency. By mechanical efficiency I mean the proportion of power delivered to motive force (overcoming drag, gravity, rolling resistance etc.) the inefficiencies (bearing friction, chain friction etc.) just generate waste heat. So, a Watt measured at the pedals is going to be, say, 0.97 Watts measured by a roller in contact with the rear wheel.Athletic efficiency is another matter. The human body is about 18-25% efficient, depending on training, genetics etcetera. That is, to deliver 1 Watt of power to the pedals, you will also deliver 3 to 4.5 Watts of waste heat, so 4 to 5.5 W in total. Anybody who has tried using an indoor exercise bike can attest to this by the pool of sweat that appears at quite moderate exercise intensities when you haven't got the air rushing past you to take all this waste heat away quickly. Put another way, for every 1g of circulating glucose you 'burn' only 180-250mg goes into the actual push delivered by muscles and the rest of the 100% goes into breathing, circulating blood, pumping sweat out onto your skin for cooling etc. etc. This excludes the costs of eating, about 10% of the energy you eat goes into digesting and assimilating that food into ready to use chemical energy inside the body but that's normally ignored in this kind of context.Lets put some practical numbers on this. I kick out around 120W at the pedals to cycle at the equivalent of 15mph on a cycle ergometer (i.e. instrumented exercise bike) that's set to simulate a flat road and still air (or 9 mph at the highest setting that represents a moderate uphill ride or a fair headwind). That's about 7 to 8 METs, where a MET is short for 'metabolic equivalent', the amount of energy used by a person sitting quietly doing nothing. So to deliver that 120W to the pedals I have to produce 600W (plus my basic 'being alive' energy that I'd use anyway). At that level of expenditure I'm breathing harder than normal, but not so hard that I can't have a conversation; so it's a workout but not a hard one. The tell-tale to how much of the total energy that is being wasted as heat is the amount of sweat that it generates if I don't have a big fan pointed at me - thirty minutes of this in an English summer and I reach the point where sweat starts dripping off my nose into a puddle on the floor.

author: amspire
author_rank: Super Contributor
timestamp: May 20, 2017, 01:24:41 pm
content: Quote from: Cerebus on May 20, 2017, 10:35:33 amI can only guess that if you train hard enough at a sport, your body learns to become much more efficient at it.I have sometimes tried to keep up the candence of the pro bike riders in the Tour de France while on my stationary exercise bike. Even with the resistance at minimum, it is really hard keeping up the same pedal rate for even 15 minutes as the pro riders going along at over 35km/hour continuously for 6 hours. With some of the champion riders, they can do this with a heart rate of under 60 beats per minute for most of the race, and in sprints, the sprinters can output 700 W of power for a hundred meters at the end of the 6 hour race. I cannot even imaging how it is possible to reach 700W.Another example is I would imagine that a top athletic sprinter and a top 10K runner are probably equally fit, and yet the 10K runner can do near minute 400m laps 25 times where as the sprinter will be really struggling after 1 lap.

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 04:55:34 pm
content: Quote from: orin on May 20, 2017, 07:59:16 amI know this sounds silly to surprisingly many people, but, especially on stationary bikes and treadmills, listen to dance music. I know that under any other circumstances I do not listen to such music, such music is nowhere near my playlists or on my portable media. But when I'm on the bike, I use music with that magic approximate 125 beat per minute speed. It even helps the quality of your workout. Though, there are only something like 40 songs I really like which are suitable for exercising and it took some effort to track them down from over the last 30 years of titles, but I would have never gotten anywhere physically without them.

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 05:32:21 pm
content: Quote from: Cerebus on May 20, 2017, 10:35:33 amI knew road bike efficiency was high, and for the really big $$$ bike roads really high, but 99% still sound shocking.Though I don't know much about athletic efficiency, but being down at 18-25% does sound realistic which means, once I get the true wattage at the peddles with those blue-tooth power measuring peddles which are basically load cells, my calories burned based on my kJ output right at the peddles would actually need to be multiplied by at least 4 as a more accurate measurement of the calories I burned, correct?As for METs, you've given me some reading to do here. I now need to find out why 'Calories = METS x weight (kg) x time (hours) Notes: Because 1 MET is equal to 1 kcal / kg / hour it is relatively easy to calculate energy expenditure of different physical activities.', if I'm sitting on a bike, why my weight affects the MET results. Without things like fat weight VS muscle weight & where it is on my body, shouldn't this be taken into account?Ohh yeah, I know about puddling sweat on the floor, I had to waterproof my electronics on my bike and protect even the mechanics. I also like to deliberately push the sweat further by wearing a 3mm thick shorty wetsuit while exercising. I can shed 10lb of water each workout like this even with a fan in my face.

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 05:52:22 pm
content: Quote from: amspire on May 20, 2017, 01:24:41 pmYes, these steroid pumping athletes operate on a completely different level than the rest of us. As for keeping up with the pedal rate, unless you are training to road race like them, your muscle build may not be designed for that high RPM. This factor may depend on your ratio of white muscle fibers VS red muscle fibers. One thing you can try is divide your RPM by 2, but, double the restive load. (This will mess everything up since you are not used to it and it takes time to adapt.) This doesn't necessarily make less calories burned, you might fair better at this RPM for the bulk of your workout, then when it comes down to that last 2-5 minute sprint at the end, you have the leverage to accelerate without worrying about adjusting anything on your exercise bike. If your normal operation is already close to your top pedaling RPM, there is nowhere further you can go to get a great sprint unless you adjust your bike's resistance at that last few minutes of workout which is an annoyance beyond hell rather than just getting up on the pedals and pedaling at all out speed.Also, on an outdoor bike, remember, as your speed increases, resistance goes up with speed ridiculously since you are primarily fighting wind on top of climb angle. On an exercise bike's resistance, it's more like changing climb angle only, no additional wind braking holding you back.

author: mtdoc
author_rank: Super Contributor
timestamp: May 20, 2017, 05:55:57 pm
content: Quote from: amspire on May 20, 2017, 04:13:35 amNot exactly. Your body will utilize glucose and glycogen stores before it resorts to converting fat and then protein to glucose. And the energy density of fat/protein/glycogen stores (primarily liver and muscle) are different.Quote from: BrianHG on May 20, 2017, 05:32:21 pmIt's a non-linear system. There are multiple adaptations to exercise and caloric input changes that occur.Quote from: IanB on May 20, 2017, 04:11:39 amExactly!

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 06:08:39 pm
content: Quote from: mtdoc on May 20, 2017, 05:55:57 pmYes, to truly loose as much weight as I have, I had to carefully monitor the largest intake killer, SUGAR in all it's bloody forms, including refined extra easy to break down complex forms like anything with white flour. Eating just under what I need so I loose fat without getting any cravings was so difficult to learn thanks to all the processed garbage food which everywhere I go within day to day life in the city.My exercise and fitness is only there for health and to be healthy enough for when I do over eat, I can burn off the excess calories without even trying, as long as the food isn't 'junk quality'. If you want to make keeping yourself in shape easy, and still include some meats in your diet, you must pay $$$ for quality food from quality sources. Yet, there are those who seem to be able to tolerate any garbage the put into their body & have no adverse effects at all.

author: jonovid
author_rank: Super Contributor
timestamp: May 20, 2017, 07:15:36 pm
content: to understand watts applied to pedals, measurement and power generation you need two wireless pressure senses on both pedals.because energy used or not used, on lifting the opposite leg on the pedal crank cycle, less the flywheel effect.that is the mass of the pedal crank itself plus the mass of the bicycle riders legs. between the seat and the crank.however as a standard bicycle puts the rider in an upright position,energy loss is in lifting the opposite leg on every pedal crank cycle, unless the rider adds foot lift.however a recumbent position can change this crank cycle.foot force vs leg mass plus total unit momentum less frictional loss.

author: BrianHG
author_rank: Super Contributor
timestamp: May 20, 2017, 08:08:18 pm
content: Power-tap pedals do measure and chart both directions, push down and pull up, of each leg, as they do clip on to cycling shoes. Their chart also logs power lost due to those who don't lift their opposite leg. Though each peddle has Bluetooth, they current only work on iOS devices.

author: Zero999
author_rank: Super Contributor
timestamp: May 20, 2017, 08:55:18 pm
content: Quote from: amspire on May 20, 2017, 04:13:35 amNo because 10kg of fat tissue is less energy dense than pure fat, as it contains some water. You've also not taken into account that the average human body uses 100W per hour to power itself: brain, heart, liver etc. and the muscles aren't 100% efficient so the actual energy consumption will be more than double 100W. In reality the body's metabolism will slow down to compensate for the starvation at some point, so it will use less than 100W per hour to power the organs, towards the end of the ordeal.