Member Question: Cramping During the Half Ironman Run

author : mikericci
comments : 0

At the midpoint of the run I felt my calves start to cramp. How do I improve my cramping resistance and are there any extra training or exercise for me to improve on?

Member Question from agicon2000

"I just finished my first half Ironman. I finished strong at 6:24 but my problem was cramping. At the midpoint of the run I felt my calves start to cramp so I had to take my Endurolites every-time I started cramping which helped somewhat and I ended up using them all with a good 6 km left to finish. I drank much water and Gatorade but it wasn't enough. Is it just that my muscles aren't used to the volume or is it the Endurolites? How do I improve my cramping resistance and are there any extra training or exercise for me to improve on? I am also a heavy sweater which could also be a factor. Please advise!"

Answer from Mike Ricci
USAT Level 3 Coach
Congratulations on a strong finish to your first half-Ironman! Cramping is a pretty common occurrence if you are lacking the right amount of fluids, sodium or are going at a faster pace than you are used to training at. All three of these details can contribute to cramps.
Finding your sweat rate
Knowing your sweat rate is crucial to keeping the cramping at bay. The easiest way to do this is to weigh yourself in the buff before a bike and/or run, then do your workout, and come back and weigh yourself again in the buff. Subtract any fluids you took in during the workout and you’ll know your weight loss. If you lost more than 2% of your bodyweight, then you would be considered a heavy sweater and need to really stay on top of your fluids. You won’t want to replace everything you lose, but you should replace about 2/3 of your fluid loss. I have an excel sheet that I keep track of different workouts I’ve done (bike and run) and the associated temperature that day so I know at X temperature my sweat is Y. This comes in handy when I go to a race and I know what the temp will be on race day. I look at my list and know that I’ll need X number of ounces of water per hour for that race.

Sodium recommendations
The other factor in helping you keep those fluids is taking in the appropriate amount of sodium during training and racing. I have found that even 500mg of sodium an hour is not enough for even light sweaters and upwards of 800mg to 1000mg per hour is probably needed for heavy sweaters. This may seem like a lot but experiment with the lower ranges first and see how that effects the cramping issue.
Too much water
Another issue is taking in too much water by itself. If you have started taking in electrolytes or a drink with electrolytes (for example we use Infinit Customized formulas) then your stomach will bloat if you take in a large amount of water by itself. The electrolytes are needed to keep the stomach emptying at a normal rate.
Proper pacing
Lastly, and this may be even more important than the sodium and electrolyte intake,  pacing the bike and run appropriately is critical to a successful long distance race, be it a biking event, running event, or a triathlon. Many times we get caught up in the moment, that it’s a race, and we feel rested, strong, there are many other competitors out racing etc – and we forget that we need to race our own race and keep things in perspective.

Starting the swim too fast, running very fast from the swim exit to the bike transition, hammering the first 30 miles of the bike, taking the first 5 miles of the run out too fast – all add up to fatigue and stress levels we aren’t used to and often end up hurting us in a long event. My advice would be to make sure you have good points of reference for your bike and run thresholds and stick to a race plan such as the following for a half Ironman.

Half Ironman race plan

Swim at a moderate effort, keeping your breathing in control and never feeling like you are going too hard. Once out of the swim, take it easy going to the transition.

Once you start the bike, break it into 3 parts. The first 18 miles think about riding a strong Zone 1 or low Zone 2, keep the cadence high and the effort easy-to-moderate. The next 18 miles can be a bit harder and you can bump the effort to a strong Zone 2. The last 18 miles are where you can keep the same effort or pick it up to Zone 3. It depends on how you feel and if you keep in mind that you have to run a half marathon when done, you might be better off just keeping your HR right at a high Zone 2.

Once you are in T2, take your time, get your HR settled and be ready to break the run down into 3 parts as well. I call this the 5/5/5 method. Use the first 5 miles to get hydrated, get some fuel into your body and generally just run easy (Zone 2). Let all the other people go out too fast and blow up later. The next 5 miles you can run like you mean it - these 5 miles should be a Zone 3 effort. The last 5k should be as hard as you can, and you can bump the HR up as high as you can manage and keep moving closer to the finish line with each step – building momentum to a nice strong finish. If you can follow the above plan at the next HIM you do, I am willing to bet you’ll take even more time off your HIM PR without the cramping.
Good luck with your training and please email me directly with any questions on my explanation!


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date: November 23, 2009