Getting technical on the treadmill - Extra Training - Brief Article

Muscle & Fitness/Hers, Jan-Feb, 2003

If you like to hit the treadmill for sprint intervals now and then, be careful you don't try to break any land speed records -- as the speed of the treadmill increases, your ability to maintain good form decreases.

Researchers from the University of Alberta, in Canada, recently concluded that velocities greater than 90% of an individual's maximal speed should be used very selectively during treadmill training. They studied the changes in stride characteristics and lower-extremity movement of six experienced power/speed athletes running at velocities ranging from submaximal to near max. As running velocity approached near maximum, the subjects experienced significant technical breakdown, reducing their efficiency and putting them at risk for injury.

So when you want to kick up your workout intensity and burn a bunch of calories in a relatively short period, limit the amount of time you spend above 90% of your maximum sprinting speed. Stick to speeds that correspond to 70%-85% of your max speed for the majority of your sprint intervals, throwing in a 90% interval only once or twice per session.

Medicine & Science in Sports & Exercise 34(4):662-666, 2002