Gracilis is a tricky little muscle. It doesn't really fit-in with the other muscles of the leg. Anatomically, it sits amongst the hip flexors, except that it runs a bit too long and attaches below the knee. Also it doesn't flex the hip.
Functionally, it's similar to hamstrings, except that it doesn't extend the hip, and it's on the opposite side of the leg.
Grouping isn't clinically relevant, but when a muscle can't be grouped, it's difficult to explain that muscle to a lay-person.
Perhaps the best explanation is this: if you feel that tight pulling in your groin when doing dead-lifts, that's gracilis. If you get that dull ache in your groin after cycling for several hours, that's gracilis.
However you try to explain gracilis, it's teeny-tiny — just a few fibres thick, but it get very tight, and VERY sore!
Gracilis, like all muscles, becomes tight and sore when it is over-loaded. In the case of gracilis, owing to it's size and location, over-loading tends to occur as a result of repetitive use rather than excessive resistance. I.e. gracillis is more likely to be injured by doing 20x5kg dead-lifts than 1x100kg dead-lift.
I've mentioned dead-lifts twice, but there are loads of different ways gracillis can be over-loaded. Essentially, anything that required bending the knee against resistance, while the hip is bent.That includes, but is not limited to rowing, road-cycling, most weight-based hamstring exercises, sprinting (but not long-distance running), elliptical training.
Once gracilis is tight, it's difficult to stretch it effectively, due to its bizarre anatomy, but there is one stretch that I find very helpful. It's a combination of a hamstring and adductor stretch. Sit with your legs spread as wide as possible. Then, while keeping a straight back, squeeze your glutes and lean forward to tilt the hips.
If you want more information on gracilis or hamstring pain, email me directly via the contact page. If you want specific information about your own injury or if you're after treatment for an injury, contact one of my clinics directly to make an appointment. Details of those clinics can be found here.
Dr Mitch Clark