When cyclists cramp in a race, it's often the large muscles in the legs that go first. Muscle cramps are a painful experience that can slow you down.
So what causes muscle cramps? The scientific community doesn't have a definitive answer, either. There are theories on what causes cramping, but no certainties. The best we can do as athletes is to review each cramping theory and compare them to our own personal experiences.
The current theories on muscle cramping include muscular fatigue, low electrolyte levels (sodium, chloride, potassium, calcium, magnesium), hyper-hydration, dehydration and personal susceptibility.
Muscular fatigue is thought to be the most likely cause of muscle cramps. When you push harder or longer than your muscles are used to, the strain can cause cramping. For mountain bike racers during the 78-mile Park City Point 2 Point, harder and longer is the most likely culprit.
Prevention: There are two ways to prevent cramping from fatigue: pacing and training. Pace yourself during the race to reflect the level at which you've trained. Riding harder in a race than you've ridden in training is a recipe for muscle cramps. A good tip is to hold back in the first half of your race to keep your muscles from becoming fatigued early. In training, push harder and longer to close the gap to the pace you want to maintain during the race. This is tough to accomplish in a 78-mile mountain bike race that takes on average over nine hours to complete—like the Park City Point 2 Point.
There's anecdotal evidence though that muscle cramps can be prevented by strength training. Perennial pro racer and multiple winner of the Leadville 100, Dave Wien's wrote this in his Road to Leadville blog.
"I lift to, hopefully, prevent cramping. So far, this has helped me at Leadville. I have lifted going into this race the last three years and I haven't cramped. In years when I didn't lift, I'd cramp coming down Columbine, but I'd just kept spinning my legs, though, and they'd go away. It certainly isn't doing my legs any good, though. I experienced the same thing in the Firecracker 50 this year—and in others—when I haven't been lifting. I'll try to get into the gym for this workout eight or nine times before Leadville, my last one being on the Monday or Tuesday before the race."