If you’re looking for a simple and inexpensive way to train the groin through hip adduction, the Slide Inner Thigh exercise is definitely worth considering. All you need is a slide board or other relatively slick surface and something to stand on so your feet will slide. This exercise can actually be done on some tile floors with hockey socks under the feet. It is usually helpful to have some sort of railing to hold onto so the athlete can pull him/herself up if they get stuck at the bottom. It is also important to progress athletes slowly from a small range of motion to a greater ROM.
Many athletes will want to “hop” up initially because it can be pretty difficult at first, especially if the surface isn’t very slick. Once they understand how to contract the adductors, they will feel how to squeeze the legs together instead of hopping up.
To increase the difficulty of the exercise, have the athlete hold a weight or figure out a way to increase the friction on the slide board. If you typically keep your slide board slick with a lubricant, try not cleaning it for a while to make this exercise more difficult.
The groin and adductors are often left untrained because many weight rooms do not have an adduction machine. This is a simple alternative that has worked well with many athletes.