First off, there is never a bad exercise, but there may be a more efficient choice.
Let’s compare the common banded clam exercise with a banded squat as a warm-up to activate the glutes, particularly the glute medius. Performing a banded clam can be challenging for some individuals, as the tensor fasciae latae (TFL) muscle can sometimes overpower the glute medius, especially during the hip flexion involved in the clam exercise. If the person performing or coaching the exercise doesn’t understand the difference, it’s easy to mistake the TFL for the glute medius.
To maximize the effectiveness of your warm-up, it’s best to use a preparatory exercise that closely mimics the targeted strength movement, such as the squat. Using the same mini band around your knees while performing a body-weight or sub-loaded squat will still activate the glute medius. By cueing the client to push out against the band, you can ensure proper execution of the movement without the TFL interfering.