Steve... the thigh should run like a pendulum on this occasion. it must always be moving.. In the mov #5 in the frames 5/6/7/8/9/10 the right thigh and in frames 18/19/20/21/22/23 the left thigh are almost stopped....
theoretically you should use 3 keys for each thigh ( frames 0/12/24 )
Ideally, in a test like this, is to animate the run moving the character forward, planting her feet in the ground on each step and not sliding them ( like I did with strawbear ). This way you can get a more realistic movements, especially in the X axis.