A new take on cramping

Dating back to the 1930s a theory was put forth that dehydration and electrolyte depletion were the primary causes of exertion cramps. This is still a popular theory that has come under fire recently. A study done in 1996 with 1300 marathon runners found the following to be primary risk factors in cramping.

• Older age
• Longer history of running
• Higher BMI
• Shorter daily stretching time
• Irregular stretching habits
• Family history of cramping

The study found no evidence of a large electrolyte imbalance in runners with cramps. Nor was dehydration deemed to be a causative factor. Other studies done throughout the 1980s and 1990s came to similar conclusions.     
The real culprit behind muscle cramps is muscle fatigue leading to abnormal functioning at the spinal level of the muscle contraction mechanism during activity. 
Receptors called muscle spindles cause muscles to contract when they are stretched. Other receptors called Golgi tendon organs (GTO) cause muscles to relax when they are contracted. Both types of receptors are needed to help protect muscles from over-stretching and over-contracting, respectively. During a normal contraction, signals from both receptors are in balance. When a muscle fatigues the activity of the muscle spindles increases (causing a contraction) and the Golgi tendon organ activity is inhibited (no relaxing) leading to a muscle cramp.

Some other theories include.

• Poor posture and inefficient movement patterns
• Carbohydrate depletion (Fully "topped up", a human being has enough glycogen stores to last for about 2 - 2.5 hours.)  
• Electrolyte imbalance (more debate as to the role electrolyte imbalances may play in muscle cramps is still needed to determine what a proper level is needed to perform well during events.)

How to prevent cramping.

• Train adequately for the conditions i.e. (pace, terrain, temperatures, duration, etc.) of your event.
• Follow a regular stretching program.
• Work on correcting any muscle imbalances or incorrect movement patterns. Develop an efficient technique required for your sport.
• Take in enough carbohydrates before and during your event. The amount will vary among individuals but aim for 250 - 400 calories per hour during the event. Take in a recovery drink/meal after your event. 
• Hydrate properly during the event, especially events lasting longer than 3 hours; using a sports drink and not just water will give you the electrolytes you need; again this will vary among individuals and conditions but aim for 125 - 250 ml (4-8 ounces) every 10 - 20 minutes.