On Fri, Apr 15, 2011 at 9:37 AM, V G wrote: > On Fri, Apr 15, 2011 at 10:28 AM, Sean Breheny wrote: > >> I think that the limitation here is aerobic respiration. Your heart >> and lungs can only get so much oxygen to your muscles. For a very >> quick burst, you can use the reserves in the blood in your legs and >> you can also dip into anaerobic respiration (lactic acid generation), >> but this cannot be sustained for more than a few seconds. So, you can >> sprint up a couple of flights of stairs (which for a 100 kg person >> going up a 10 meter flight of stairs in 5 seconds is about 2kW or 3 >> Horsepower), but you cannot sprint up 10 flights of stairs. >> >> There may also be a thermal dissipation problem in your leg muscles. >> >> I wonder if an ultra-fit marathon runner or cyclist could sustain >500 >> Watts for minutes? >> >> Sean > > > They can. A trained athlete can sustain 1 kW for a short time, maybe a fe= w > minutes. This spreadsheet on this page gives watts/kg for different classes of athle= tes: http://home.trainingpeaks.com/articles/cycling/power-profiling.aspx If you can do 1kW for more than a minute, you are better than most professional athletes. (I work for a company that makes bicycle power meters. 1kW is hard! I can reach it for about one second. That puts my W/kg somewhere below the "untrained" figure in the chart...) Regards, Mark markrages@gmail --=20 Mark Rages, Engineer Midwest Telecine LLC markrages@midwesttelecine.com --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .