The large bones that make up the hip joint also serve as anchors for several muscles. A muscle strain occurs when overuse or injury stretches/tears the muscle fibres. A forced contraction of a stretched muscle is the most common cause of a muscle strain in the hip region. A fall or direct blow to the muscle, overstretching and overuse can also stretch/tear muscle fibres, resulting in a strain.
Predisposing risk factors of Groin strains include:
• Prior injury to the area
• Not warming up properly before exercise
• Doing too much to quickly i.e. Not allowing for a gradual progression into exercise/sport
There are three muscle attachments that are commonly injured:
• The adductor muscle origin at the pelvis
• The hip flexor (iliopsoas) origin onto the medial side of the thigh bone (femur) just below the hip joint
• The rectus femoris (a portion of the quadriceps –anterior thigh muscle) origin into the anterior/superior aspect of the pelvis
The general signs and symptoms of a groin strain are:
• Pain over the injured muscle is the most common symptom of a hip/groin strain.
• Using the muscle aggravates the pain.
• Swelling may also be present, depending on the severity of the strain.
• There may be a loss of strength in the muscle
The adductor muscles bring the thighs in together. A strain in these muscles can be of gradual onset or specifically related to a single incident. They commonly occur with high side kicks, sliding tackles and in those doing the splits. In those in which the strain has been occurring gradually there is usually a period of gradually progressing stiffness and discomfort after prolonged or difficult work/activities involving the adductor muscles. The pain and tenderness is usually in the midline of the groin crease. Stretching i.e. wide separation of the legs and resisted contraction of the muscle i.e. pulling the knees together under resistance will exacerbate the pain.
Hip flexor (iliopsoas strains)
The hip flexor muscles allow you to lift your knee and bend at the waist. Hip flexor strains occur from overuse of the muscles i.e. repeated hip flexion (bending) against resistance e.g. high knee kicks, repeated sit ups, forceful kicking like in soccer. The pain is usually felt just below the groin crease. As the muscle is very deep it is difficult to localize an area of tenderness. Again stretching and resisted contraction of the muscle will reproduce pain. In some cases due to the muscles attachment in the lower back, back pain may also be a presenting feature.
Rectus femoris strain
The rectus femoris is a portion of the larger quadriceps muscle. It is this portion of the quadriceps that crosses over both the hip and knee. Its action is to bend (flex) at the hip and straighten (extend) the knee. It is commonly strained in sprint starts and during kicking especially where the kick is blocked. There is pain and tenderness just above the hip joint and pain will be exacerbated if the hip is flexed against resistance.
Diagnosis and treatment
According to the history of the condition and physical assessment your physiotherapist will be able diagnose Groin strains and which of the muscle groups is involved. If the strain is severe then x-rays may be done to rule out any fractures of the hip that may have occurred if the muscle when strained has pulled the bone as well.
Physiotherapy treatment of groin strains would initially aim to reduce pain and inflammation. This may include the use of electrotherapeutic modalities, ice, movement in pain free range, gentle massage. At this time rest from sport/activity is essential to allow healing to take place. Healing usually takes about 6 weeks and over this time competitive sport should be avoided. Once the initial pain has settled your physiotherapist will guide you through a gradual progression of stretching, and strengthening exercises. Your physiotherapist will also assess and treat/correct any predisposing factors (e.g. poor sports action, abnormal lower limb biomechanics) and assist in your gradual return to sport.