If you ever find the day after a squat/leg workout (or cycling, sprinting, horse riding etc) you feel so sore you can’t really walk or stand or breath properly – this may be a tight pectineus.
The pectineus is one of your many groin/ adductor muscles. The difference between this muscle and other groin muscles is its proximity and connection to the psoas and illiacus. These three muscles are intertwined within their fascial fibers. If one muscle is dehydrated and tight, the others will follow suit. In addition, the psoas is connected to the diaphragm in a similar fashion.
Try this deep inner groin stretch to release the hard to reach pectineus:
Lie on your side with a therapy ball on a block (or book). The ball should be level with
Bend your knee and raise your leg so your upper inner thigh rests onto the therapy ball. Feel the ball underneath your inner thigh. Be careful: there is the femoral artery, nerve and vein close by; if you feel any electric/pulsing sensation, get off that area. The ball should be close to your groin. In this picture I am pressing my left knee into the ground diagonally towards my right shoulder (without moving it) to activate my pectineus. It is a subtle sensation. If you have localised discomfort or discomfort into the pelvis you have arrived on your pectineus! If you feel discomfort down the leg you need to place ball closer to your groin. Once you have found the spot, relax your knee and gently tilt the pelvis backwards and forwards.