Occasionally I get a slew of e-mails like this that pertain to the same problem. This year’s number one topic seems to be muscle cramps. Cramps in calves, the diaphragm, triceps. Wherever they occur, a painful cramp can slow down a good race or bring it to an abrupt halt.
My inquirers wonder, could diet or hydration be the cause?
While it isn’t possible for me to diagnose nutrition problems based on brief information provided remotely via e-mail, I can offer some educated guesses about what causes and what can prevent cramping muscles in the early part of a race.
The human body is pretty remarkable in that it can usually pull out of storage any nutrients that are required in the short term. When cramping occurs near the start of a race, one likely cause is the recruitment of different muscles to perform that which has not been adequately trained.
Specifically, I am referring to the type of muscle known as a fast oxidative glycolytic, or FOG muscle fibers. FOG fibers are able to contract more rapidly than the slow-twitch fibers endurance athletes primarily rely on during training. Come race day, however, unless interval workouts have been done at the appropriate intensity to stimulate the FOG muscles to improve their aerobic capacity, acid accumulation can cause early fatigue and possibly cramping.
Many athletes avoid interval training for the obvious reason: It’s painful. Pushing FOG muscle fibers toward lactate threshold, however, can result in a sort of chain reaction. The stress of muscular work acts as a stimulus to start the production of signaling enzymes. These signaling enzymes, in turn, stimulate other enzymes, and eventually transcript genes to increase the number of mitochondria – the nano chips of aerobic metabolism – found within the muscle. The more mitochondria a muscle has, the higher the intensity of aerobic work that can be performed.
For those of us who are not fans of “no pain, no gain” workouts, there is good news. Recently some researchers have challenged the notion that chronic high carbohydrate diets and daily training are the only way to build up the metabolic machinery of FOG muscle fibers. Could there be a more efficient way to make more mitochondria? Could be.
Spare the carbs
Picture this scenario: You want to get ready for an upcoming race but it’s only a month away. Your coach offers you two choices for high intensity training for the next three weeks. The choice is to 1) train once a day, four days a week or 2) train twice every second day, two days per week. Both choices amount to a commitment of eight hours per week for three weeks.
If you choose the one workout per day approach, you will alternate between a 100-minute bike rides at a moderately high pace on day one and high-intensity interval training (eight intervals of five minutes each) the next for four consecutive days each week.
The second choice, to train twice every other day, would require the 100-minute ride first, resting for an hour, then doing the intervals. If you opt to do this, no carbohydrate intake of any amount is allowed after the first exercise of moderately hard, steady cycling. This choice is known as “training low” because no carbohydrate is available.
Which would you chose?
In a research study published in The Journal of Applied Physiology in 2008, the same protocol described above was followed. The results showed training “low” stimulated enzyme production necessary to increase aerobic capacity was higher for the twice-a-day group with no carbohydrates than the daily exercising group.
How did the training regimens compare in a time trial test? Both groups improved. The training “low” group showing a 12 percent improvement and the group that trained normally saw a 10 percent improvement after three weeks. Although the time trial results were not significantly different, the researchers concluded carbohydrate manipulation did stimulate enzyme production associated with increased oxidative capacity to a greater extent, likely due to augmented stress on the muscle under conditions of low fuel availability.
Support for the “low fuel/high stress” theory of training is gaining. In the January 2010 edition of The Journal of Applied Physiology, Andrew J.R. Cochran of McMaster University in Ontario, Canada, found enzymes associated with oxidative capacity increased by as much as 70 percent when no carbohydrate is supplied versus a 19 percent increase when training is done with supplemental carbohydrate taken during exercise.
Finding the most effective method of training is an ongoing science. Training low may offer a way for an athlete to reduce body fat because of the decrease in carbohydrate intake and increased utilization of fat during exercise.
The flexibility of scheduling a two-a-day training program on alternate days may be appealing to the athlete who cannot fit in training on consecutive days.
Training “low” does have some risk, though. First, an athlete may have problems maintaining energy during endurance training if total carbohydrates in the daily diet is insufficient to maintain glycogen stores. There is also increased risk for illness following intense exercise. Consuming carbohydrate during exercise reduces the stress hormone cortisol, which suppresses the immune system.
Racing high
While training without supplemental carbohydrate may be effective to stimulate increased aerobic capacity, it would be wise to consider it as only a short-term strategy for training. Currently, the train “low” concept is still regarded as experimental.
There is, however, an enormous amount of research to support consuming carbohydrate during exercise to prolong endurance. In addition, carbohydrate loading to promote carbohydrate availability during exercise can also improve performance.
While more research is certainly going to be done on training “low,” for now it appears there is no sure shortcut for getting FOG muscles into racing shape. Whether you chose to experiment with low carb workouts or grab a sports drink and train high, enjoy the ride and the race.
Donna Marlor, MA, RD, CSSD, is a registered dietitian who specializes in nutrition for endurance exercise and weight management. She offers motivational coaching and behavioral skills training to change eating patterns. Marlor is a consultant for the U.S. Olympic Education Center in Marquette, Michigan, and works with many individual athletes, from novice to elite. A former collegiate alpine and cross-country ski racer, Marlor continues to enjoy master’s level competition as a Nordic skier and runner. She and her family and chocolate Lab undertake many outdoor adventures in Upper Michigan, where they reside. Marlor can be reached via www.DonnaMarlor.com or at 906/360-4069.
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