In the study, 10 cyclists did one of three warm-ups before simulated races: hard cycling, moderately hard cycling, or no warm-up. The moderately hard warm-up group rode for a longer time before having to quit from exhaustion compared to the other groups.
Why? Both warm-ups helped muscles use oxygen more efficiently faster, the researchers found. When you start working out, your muscles rely mostly on anaerobic energy stores, transitioning gradually to using mostly oxygen for fuel. However, anaerobic energy produces byproducts that can contribute to fatigue. So by speeding up the switch over to using mostly oxygen, you can ward off some of this fatigue, allowing you to exercise longer, says study author Mark Burnley, Ph.D., of Aberystwyth University in the U.K.
The hard warm-up group probably didn’t see any performance improvement because 10 minutes of rest wasn’t long enough to recover for the race, Burnley believes.
So what’s a good warm-up for runners or bikers? Head out for 6 minutes slightly below your race pace, Burnley suggests. Finish the bout 10 minutes before your race starts. For sports that require jumping and other power movements—like a baseball or soccer game—add in some dynamic stretches