AIS Sports Nutrition

Cramps and Stitches

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Just about everyone who has ventured onto the exercise arena has experienced either a cramp or a stitch at some time.  These complaints can range from mildly uncomfortable to severely debilitating and are a great source of frustration to everyone from recreational exercisers to serious athletes.  Unfortunately, scientists know very little about the two conditions and how to avoid them.  Consequently, there is a lot of folklore surrounding the topic, making it difficult to know exactly how to deal with these problems.

What is cramp?

Cramps occurring during exercise are referred to as Exercise Associated Muscle Cramps (EAMC),  to distinguish them from those that may occur at rest or as a symptom of an underlying medical condition.  EAMC’s are best described as a sudden, tight and intense pain that most commonly occurs in the in the muscle groups directly involved in the exercise task e.g.  gastrocnemius (calf) while running.  They can range from a slight twinge to an excruciating pain, and may last for a few seconds or several minutes.  An EAMC can be a one-off or occur several times before the muscle relaxes and the pain goes away.

What causes cramp?

EAMC’s occur when a muscle involuntary and forcibly contracts and does not relax.  While this seems to be due to an abnormal stimulation of the muscle, the exact mechanism is unknown.  Cramp is more likely to occur in tired muscles and ones that are already in a shortened position.  Therefore poor fitness or exercising at high workloads can increase the likelihood that they will occur, while poor stretching habits may also contribute.
While dehydration has for a long time been associated as a possible cause of EAMC, a number of recent studies of marathon runners and ultra-endurance athletes have shown no difference in the hydration status of those experiencing EAMC and those that have not.
Sodium is involved in initiating nerve signals that make muscles contract.  While some athletes will incur large losses of sodium during exercise secondary to a high concentration of sodium in their sweat and/or high sweat losses, the evidence that this can lead to cramp is still inconclusive.  Cramp has been attributed to the depletion of potassium and minerals such as calcium and magnesium.  However, this idea does not have strong support as very little potassium, calcium and magnesium is lost during exercise. 
The use of creatine has been linked to cramps, based on anecdotal reports from athletes, and the hypothesis that a creatine-loaded muscle cell may become so "full" with the storage of creatine and fluid, that the integrity of the membrane is disrupted.  Although this theory is interesting, studies that have followed the cramping and injury outcomes of groups of athletes have not found any difference in the prevalence of problems occurring in creatine users and non-users.

How can I avoid cramp?

• Allow adequate recovery and rest for muscles after hard training sessions.
• Increase strength and fitness.  Stronger, fitter muscles are more resilient to fatigue and therefore cramp. 
• Be cautious when changing speed or intensity especially during the later stages of exercise.  Fatigued muscles take longer to adapt to increased workloads.
• Wear comfortable, unrestrictive clothing and footwear.
While there remains little strong evidence that dehydration is associated with EAMC, it’s still important that athletes practice good hydration practices both before and during exercise to optimise training and competition performance.  See both the “How much do athletes sweat?” and “Fluid – Who needs it?“ fact sheets for more information.

How should cramp be treated?

Resting and stretching helps to decrease the muscle contraction and allow the muscle to relax.  Massaging the area may also assist, while applying ice can stop the spasm and help to relieve the pain. 

What is a stitch?

In the scientific literature stitches are referred to Exercise-related Transient Abdominal Pain and are described as localised pain usually felt on the side, just below the ribs, which sometimes accompanied by a stabbing sensation in the shoulder joint.  The pain can range from sharp or stabbing to mild cramping, aching or pulling.  Sometimes people can exercise through the pain, though usually the sufferer is forced to slow down or cease exercise.  Stitches usually disappear within a few minutes after ceasing exercise however some people experience some residual soreness for a few days, especially after severe pain.  While the stitch seems to be more prevalent in activities that involve vigorous upright, repetitive movement of the torso e.g. running and horse riding, it can occur in any type of sporting activity.

What causes stitches?

Scientists are unsure of the exact cause of stitches.  For some time, they were thought to be caused by a reduction in blood supply to the diaphragm, a large muscle involved in breathing.  It was suggested that during exercise, blood was shunted away from the diaphragm and redirected to exercising muscles.  This theory has now lost favour with scientists as both the diaphragm and the limb muscles need to work harder during exercise, so it is unlikely that an inadequate blood flow is directed to the diaphragm.  Another popular theory is that stitch is caused by organs pulling on the ligaments that connect the gut to the diaphragm.  Jolting during exercise may cause these organs to pull on the ligaments and create stress on the diaphragm, though this theory does not explain the incidence of stitches in athletes involved in sports not involving a significant jolting action e.g. swimming.
A more recent idea is that stitch is caused by irritation of the parietal peritoneum.  Two layers of membrane (peritoneum) line the inside wall of the abdominal cavity.  One layer covers the abdominal organs, while the other layer (parietal peritoneum) attaches to the abdominal wall.  The two layers are separated by lubricating fluid, which allows the two surfaces to move against each other without pain.  It is thought that the stitch occurs when there is friction between the abdominal contents and the parietal peritoneum.  This friction may be caused by a distended (full) stomach or a reduction in the lubricating fluid.  The parietal peritoneum is also attached to the phrenic nerve, which refers pain to the shoulder tip region, which may explain the shoulder pain that has been described by some athletes.

How can I avoid stitch?

Eating too closely to exercise or consuming inappropriate foods seems to increase the chances of athletes experiencing a stitch during exercise.  High-fat and fibre foods are more likely to cause problems.  The likelihood of stitch occurring may be reduced by allowing 2-4 hours before exercising after a large meal and choosing high-carbohydrate, low-fat and moderate to low protein options in the pre-exercise meal. 
Immediately before and during exercise, athletes should avoid consuming highly concentrated fluids such as soft drink, cordial and fruit juice, as they seem to increase the risk of stitches occurring during exercise.   These type of drinks empty more slowly from the stomach than both water and sports drink, thereby leaving the stomach more distended for longer.  It is also preferable for athletes to consume small amounts of fluid regularly during exercise, as this is better tolerated than large volumes of fluids being consumed at one time. 

How should stitch be treated?

Sometimes the stitch eases if you slow down and drop your intensity for a period.  However, the most common way to alleviate stitch is to bend forward while pushing on the affected area and breathing deeply.  Sometimes this can be done while exercising but usually the pain eases more quickly when exercise is ceased.  Another option is to lie down while elevating your hips.

Does stitch indicate a more serious problem?

The stitch is rarely a sign of more serious problems.  However, any pain that is persistent and does not ease when exercise ceases should be investigated by a doctor.

 

Written by AIS Sports Nutrition, last updated November 2009. © Australian Sports Commission

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