Unity mecanim run animation not smooth.

I created a simple run in blender, and in blender I made it so that the character run while he moves forward. I exported it as .fbx, imported it into Unity and made all the correct settings. But now when I play the animation, the character run, but he doesnt appear to run naturally, it’s like he isn’t running, but just sliding forward while moving his legs like he is running. How can I fix it that the run becomes naturally?

run in blender: blender - YouTube

run in unity3d: unity - YouTube

The animation doesn’t loop well, the speed at the animation’s end doesn’t match the speed at the start. Check the y axis curve (in blender) and make sure the transition between the start and the end is seamless.