Answered by on Monday, October 12, 2009
When any muscle is shortened for a prolonged period of time, it's likely to cramp up, and "crunches, by their very design, keep your abdominal muscles in a shortened state," says Daniel Vigil, M.D., a team physician for the USA Track & Field. You might be able to avoid painful cramping by changing the type of crunches you do. For instance, rather than doing crunches on a flat surface, try doing sit-ups on an inclined bench. "By being on an incline, your muscles are at a more lengthened position, and they won't be in a contracted, shortened state for too long," says Malachy McHugh, Ph.D., research coordinator at the Nicholas Institute of Sports Medicine and Athletic Trauma in New York City's Lenox Hill Hospital. McHugh also suggests doing a non-abdominal exercise in between sets of crunches to give your abs a brief rest. If changing your workout doesn't work to alleviate the pain, your cramping may be the result of something else altogether. "Although cramping isn't thoroughly understood by doctors and sports scientists, theories include dehydration and muscle fatigue," says Dr. Vigil. To thwart these possible cramp triggers, Dr. Vigil suggests doing an adequate warmup, taking frequent trips to the water fountain to stay hydrated, and incorporating abdominal stretches between sets.