Develop your running speed and stride length with the 11000 leg speed builder from Power Systems. These tubes attach with a shoe fitting with multiple rings. The bands are than attached to a stationary object and provide resistance to the legs for any number of running exercises. When stretched to 100 percent of their original length, the bands provide 14 lbs. of resistance; at 200 percent of their original length, they provide 20 lbs. of resistance. You can set up your exercises to work on either 1 or 2 legs. Order your running training equipment here.