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marathon cramp

Marathon Cramp: A marathon to remember

marathon runnersSean Fyfe investigates why his meticulous preparation for the London event could not save him from a day of pain and disappointment.

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Last November I set out to achieve one of those lifetime goals: to complete a marathon in less than three hours, considered by many to be the Holy Grail of social distance running. What better occasion to do it than at the 25th anniversary of probably the greatest race in the world, the London Marathon.

Your editor had pressed me into keeping training logs so I could report back to readers on the perfect preparatory regime for the aspiring sub-three hour runner. But my fairy tale turned into a minor horror story, leaving me with some rather different learning points to pass on than those I had originally expected to be writing for you. My downfall was an extreme and irreversible onset of cramping, which began at the 15-mile mark and became intense throughout my legs by 20 miles, causing me a very painful and drawn-out finishing stretch. During those last agonising six miles, I think I said ‘never again’ at least a hundred times.

Having recovered, I have looked back methodically at my preparation. It could not have gone better to plan: no injuries or illness to make a serious impact on my training; a slow, steady build-up in mileage with four runs over 20 miles; a half- marathon in 80 minutes five weeks before the main event; a two-week taper which I felt refreshed my body; plenty of healthy food, particularly in the last two weeks; carb loading for 72 hours and lots of fluids.

During the race I felt as though I was running a controlled first half (1:27:30), considerably slower than my half- marathon time, which was done in very difficult windy conditions and without a taper. When the cramps started, I was nowhere near feeling exhausted, and the distance was well short of what I had done comfortably in training. So you can understand why I felt perplexed at the end of the race (not to mention humiliated – my girlfriend ran a considerably quicker time than my eventual 3:43:55 and my mates have promised never to let me live it down…).

Cramp or ‘Charley Horse’ can be described as a painful spasmodic, involuntary contraction of skeletal muscle that occurs during or immediately after exercise. The most frustrating thing about cramps is that no one truly knows what causes them. There are many theories, from old wives’ tales to others with solid supporting evidence. In reality cramps probably have multiple causes and that is what makes them so unpredictable.

Traditionally cramps have been explained as the result of dehydration and an electrolyte imbalance, and this is still the most popular argument. However, there have been studies that contradict this theory. In the 1980s, a study that tested a group of male runners before and after they ran, found no difference between those who cramped and those who did not, in terms of changes of blood volume or blood levels of sodium, potassium, bicarbonate, haemoglobin and hematocrit.

Injury risks to marathon virgins

Men and women embarking on marathon training programmes are at significant risk of injury because of their lack of experience, according to a major study carried out in Texas – the first to describe the baseline characteristics of a large representative group of non-elite athletes and their relationship to injury risk factors.

A four-page questionnaire was completed by 1,548 of 2,314 people registering for the 1998-99 Houston Fit Marathon Training Programme, a 25-week running or walking programme designed to help individuals achieve their fitness goals while training for the Houston Marathon.

Key results were:

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  • 3.5% (mostly women) were underweight and 35.6% (mostly men) were overweight or obese;
  • the mean number of years of running experience was 6.2 and only 10.2% had competitive running team experience, in most cases dating back to school days;
  • the majority (52.3%) had not previously trained for a marathon and, of those who had, 28% had not completed a marathon;
  • about a quarter of the sample either had done no previous running or had been running for one year or less;
  • just over 16% (more women than men) had been physically inactive in the three months prior to starting the programme;
  • 38.1% reported having had an injury during the previous three years and 35% of all injuries were still causing symptoms.

Clin J Sports Med 2002; 12: 18-23
(from ‘Marathon Training’ Special Report, Peak Performance 2004)

Cramping is also commonly seen as a symptom of ‘hitting the wall’ (or ‘bonking’), when an athlete completely uses up their muscle glycogen stores. To deplete fully stored muscles takes 2 to 2.5 hours of exercise.

A more recent theory examines cramp in the context of neural control of the muscle under fatigue. Schwellnus (1) suggests there is a disruption at spinal level which causes inhibition of the golgi tendon organ (GTO) nerve receptors, and thereby over- activation of the muscle spindles, resulting in the sustained contraction of the muscle. They also cite the fact that cramping occurs in biarticular (two-joint) muscles that are mostly shortened in the running cycle. It is in this position that tendons are under less tension and the GTOs are less active. A poor stretching regime during training is also considered a factor with neural related cramps, the argument being that an exaggerated reflex contraction due to a lack of, or irregular stretching, could increase muscle spindle activity.

I could not, however, confidently conclude that any of the above theories was the cause of my cramps. I needed another explanation. Hyponatremia (low blood sodium) is a well known cause of cramps, but is thought mostly to affect ultra endurance competitors, such as the 54mile marathon runners or Ironman triathletes.

Recently though, hyponatremia has been discussed more in the context of the 26-mile marathon. The body needs to maintain the right levels of blood sodium in order to draw the right amount of water into cells through the membranes. It doesn’t matter how much water you drink, if you have low sodium levels you can’t absorb any of it.

Other symptoms of this potentially very nasty condition include bloating, upset stomach, nausea, headaches, disorientation, slurred speech, confusion, collapse, convulsions or even death. Hyponatremia doesn’t have to relate to sweating out salts (usually the problem in hotter climates); it can also be a problem in cooler climates where athletes consume too much water and then sweat less than they normally would, inadvertently diluting their blood sodium concentration.

When I look back at my preparation I have come to the conclusion that I over- hydrated and suffered a mild case of hyponatremia. For days beforehand, and particularly the day preceding and morning of the race, I drank a huge amount of water, thinking that the last thing I wanted was to be dehydrated. The water bottle never left my side and I remember having to visit the toilet at very regular intervals.

I can only assume that I passed too many electrolytes and my sodium levels became low. Rather than consuming too much water during the race, which is often the case in ultra-distance events, I think I created my problem before the race began – a documented cause of hyponatremia. It is suggested that athletes ingest sodium chloride tablets before and during ultra-distance events to prevent hyponatremia. Sports drinks are a help, but on their own do not contain enough sodium to return adequate levels to the system, however much of them you consume.

As I crossed the finishing line in pain, I saw the official finishers’ T-shirt logo ‘never again… until the next time’, and had to smile. Of course I shall never be satisfied with my finishing time, and I have to do something to restore my credibility with my mates.

Although I feel as though I overhydrated before the race without providing my body with any source of sodium, I think it is important to still consider all the other options and try to cover all the bases in preparation for any endurance event such as the marathon. If anyone has any other opinions or advice then I am sure everyone would love to hear from you.

Sean Fyfe is a physiotherapist working with Metis Physio Centres in London, a multi-disciplinary clinic. He works with elite dancers and theatre performers

References

  1. Schwellnus MP, ‘Skeletal Muscle Cramps During Exercise’ Physician and Sportsmedicine 1999; 27 (12)

Further reading

www.spinalhealth.net/hyponatremia.html
www.back-in-business-physiotherapy.com.au/triathloncramps%5B1%5D.pps
www.thesportfactory.com/article_268.shtml

marathon cramp