WTFL???? What is the Tensor Fasciae Latae (TFL) The Tensor Fasciae Latae, or TFL to its friends, is a small muscle in the outside front of the hips that works very, very hard. The TFL is a multi-tasker. It does hip flexion, hip abduction, internal rotation, and it even internally rotates the lower leg through its attachment to the IT band.       Because the TFL has so many abilities, it is often overworked. It’s just so easy for other muscles to lay back and let the TFL take over. The TFL is also