Muscle cramps are involuntary spasms or contractions in one or more muscles. They are most common in the back of the lower leg, and in the inner thigh, also known as the groin. Experts say that muscle cramps can be "mild," but most of us don't experience them that way. They are most common in children, teens, and active young adults, and in people over the age of 50.
Why should cramps so often affect the groin?
The "inner thigh" muscle is known as the adductor magnus. It starts above the legs and runs down the medial (inner) side of the thigh. It keeps the legs from plopping outward while we stand or walk. The adductor magnus is a powerful muscle that has not just one but two nerve connections to the spine, making it (please forgive the oversimplification) twice as susceptible to transmitting pain signals.
Walking, running, and riding put a lot of strain on the inner thigh muscle, which has to have an unusually "tough" connection to tendons. The body's trade off for injury protection is a poor blood supply, something like the poor blood supply to the Achilles tendon of the heel. The combination of tough connective tissue and poor blood supply make this muscle unusually susceptible to pain and unusually slow to heal after injury.
Injury to this muscle usually occurs after a "forced kickoff," an intense side-to-side muscle. When someone changes direction suddenly, the adductor muscles of the inner thighs have to "fight" the abductor muscles at the outer sides of the thighs. The inner thigh muscles have to contract rapidly, which may tear the connection to the tendons.
The kinds of activities that cause this kind of injury in sport are obvious:
- Changing directly suddenly in tennis,
- Tackling someone in American football or rugby, or
- Suddenly taking off in a sprint from a resting position.
However, the inner thigh muscles can also be injured in non-athletic activities, such as:
- Hopping on or off a bus,
- Using a step ladder and having to prevent a slip or fall, or
- Stepping around an obstacle, even just once.
There are some times that a visit to the doctor is a must, especially with teenagers:
- Teens who do "clean and jerk" weight lifting are especially at risk for a condition called Legg-Calve-Perthes disease (LCP). What starts out as simple soreness progresses to inner thigh pain that radiates up and down and just won't go away. This can be caused by avascular necrosis of bone, bone death caused by injury to its blood supply. If inner thigh pain gets worse and worse and is accompanied by loss of mobility, a visit to a doctor competent in sports medicine is called for.
- Teens, especially boys, who are either tall and lanky or short and obese are at risk for a condition called slipped capital femoral epiphysis (SCFE). It can come on either after an injury or after too much repetitive motion. It spreads to the inside of the knee and can cause a limp.
Both of these conditions require medical care. Most of us, however, can deal with inner thigh muscle cramps on our own. Here are some key points:
- Most sports injuries are treated with rest, ice, compression, and elevation (RICE), but the injuries that cause inner thigh cramps are treated with protection, rest, ice, compression, and elevation (PRICE). Walking with a cane (held in the hand opposite the injured leg) to take weight off the muscle, and avoiding exercise for a few days, reduces the recurrence of cramps.
- Stretching muscles immediately after cramps can make the problem worse.
- As long as your inner thighs are tight and weak, they are prone to re-injury.
- Steroid injections can make the problem worse if the injection is made into the tendon itself.
- It's important to realize that a warm-up will relieve pain, but the pain will come back if you exercise too hard.
- Rapid movement side to side triggers recurrence of pain.
- The injury that causes inner thigh muscle cramps won't cause loss of mobility unless there is damage to the blood supply, but if you can't walk, you must see a doctor.
- Your doctor may prescribe muscle relaxant drugs such as baclofen (Gablofen, Lioresal) and tizanadine (Zanaflex) for short-term relief.
- Most people get better results form taking supplemental magnesium (just 400 mg a day, no more) than supplemental calcium and vitamin D. If you take supplemental calcium and vitamin D, then you also need supplemental vitamin K2 (usually combined with a vitamin D supplement).
- TENS (transcutaneous electroneural stimulation) relieves pain, but without PRICE, including protection of the affected muscle, it can't address the underlying problem.
Many people who have inner thigh cramps may not think of themselves as athletes, but usually sports medicine principles apply. Treat yourself like an athlete, and you will likely achieve freedom from muscle cramps much faster.
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