Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling - Muscles tire on short/slow and ok on fast and long rides + GPS calorie question....

Hi. It will sound like a strange question, but my muscles are getting really tired when I'm riding with my 5 year old son. Most rides are anywhere between 8 and 25 miles, with average speed around 6 mph.
On other hand, I can do 50-100 mile ride easily, without any discomfort with an average speed around 12-13mph.
The most interesting thing is that my Garmin 305 is showing more calories burned per mile on slow rides with my son that when I'm riding fast and by myself...
Can someone provide some easy explanation why its like that?

I find that slow rides with slow riders wear me out too. I haven't really figured out why that is, but I wonder if I'm using the wrong gearing or some other riding style related difference. As far as the calorie question goes, no clue.

Your five year old rode 25 miles.

His legs sure must be very tired.

Your five year old rode 25 miles.

His legs sure must be very tired.

He rides almost everyday, and he is perfectly fine after 25 mile ride and even asking for more. He did already around 550 miles this year, and over 20000 ft elevation gain. Did I mention that he wants to be like a Bredley Wiggins or Lance Armstrong? ;-)

I would suspect this has to do with efficiency.

Coming from a racing background, I'm used to seeing cyclists who are really slim and fit and who eat a lot. When I tapered down my racing and started doing recreational rides on the tandem, I tended to see more of cyclists who were a bit plump and overweight, but who could still ride the distances at good speeds, and who ate a lot.

So I've come to this theory that at some point, if you are not doing hard race-oriented training (like intervals and hill repeats where you are going anaerobic and experiencing muscles burning), your body becomes really efficient at spinning along aerobically, even at reasonably high speeds (not at threshold, but comfortably below). And I mean REALLY efficient, to the point that you are not burning as many calories as you used to have to burn. But, being used to eating a lot, these overweight recreational guys continue to consume the amounts they think are the entitlement of this "usual" amount of exercise.

So when you change your mode of cycling, by either going harder, or even by going much easier (which requires maybe different muscles, or muscles firing in different sequences, or weight transferred differently), the body becomes less efficient, and you appear to be burning more calories.

That's my theory, anyway. And my anecdotal evidence is that I'm 6'1" and 170-175 lbs, and I've done century rides (in miles) in cool weather on a fixed gear bike on less than one bottle and a few pieces of fruit, with no problems. I don't remembe rthe last time I've bonked, and I'm not sure I could bonk if I wanted to. The body is just too efficient... And I can't do slow rides, too frustrating, but I just thought that was the Type A in me.

Luis

I would suspect this has to do with efficiency.

Coming from a racing background, I'm used to seeing cyclists who are really slim and fit and who eat a lot. When I tapered down my racing and started doing recreational rides on the tandem, I tended to see more of cyclists who were a bit plump and overweight, but who could still ride the distances at good speeds, and who ate a lot.

So I've come to this theory that at some point, if you are not doing hard race-oriented training (like intervals and hill repeats where you are going anaerobic and experiencing muscles burning), your body becomes really efficient at spinning along aerobically, even at reasonably high speeds (not at threshold, but comfortably below). And I mean REALLY efficient, to the point that you are not burning as many calories as you used to have to burn. But, being used to eating a lot, these overweight recreational guys continue to consume the amounts they think are the entitlement of this "usual" amount of exercise.

So when you change your mode of cycling, by either going harder, or even by going much easier (which requires maybe different muscles, or muscles firing in different sequences, or weight transferred differently), the body becomes less efficient, and you appear to be burning more calories.o

That's my theory, anyway. And my anecdotal evidence is that I'm 6'1" and 170-175 lbs, and I've done century rides (in miles) in cool weather on a fixed gear bike on less than one bottle and a few pieces of fruit, with no problems. I don't remembe rthe last time I've bonked, and I'm not sure I could bonk if I wanted to. The body is just too efficient... And I can't do slow rides, too frustrating, but I just thought that was the Type A in me.

Luis
Great theory. I'm couple inches taller than you,and about 100 lbs more... I'm not fat, but I'm not skinny butt either. I'm burning anywhere between 2000 and 10000 calories on most of my rides, and I'm shocked that u did century ride with so little water and food. I don't recommend it to anyone...