I'm 47 years old and have been running since I was 19. Meanwhile, I've had two children and after four surgeries for colon cancer, I am cancer-free.
Training for and running the marathon distance is my way of celebrating the fact that each day is a gift. My goal is to qualify for Boston and I need a 3:55 time for my age. I recently ran a marathon and had some unexpected problems--my goal time for the race was 4:00 to 4:10, but at mile 18 my legs started cramping so badly, I ended up walk/jogging much of the last eight miles and finished 4:32.
Leading up to the race, I trained conservatively--four days a week, alternating with strength training three times a week. My total weekly mileage was 35 to 38 on weeks that included a long run of 16 to 21 miles (four long runs leading up to the race), and 28 to 30 miles a week on the alternate weeks.
Each week included speed work, tempo runs, hills and eight to 10 miles at marathon pace. During the marathon I was well-hydrated, ate a gel every 40 minutes, and the race temperature was perfect--about 40 degrees and no wind.
My splits went from under nine minutes to well over 16 minutes for mile 25. Cramps hit my quadriceps and hamstrings at mile 18. With stretching, walking, and jogging I was able to finish the race.
How can I avoid the agony of those cramps and achieve the under-four-hour time I need for Boston?
Congratulations on your incredible accomplishments, not the least of which was finishing the marathon despite your terrible leg cramps. Trimming 32 to 37 minutes will require greater intensity and more volume. Run as much as you can without getting sick or hurt.
It is a fine balance to achieve the necessary training gains without overtraining. Better safe than sorry--you may need to stage your goals in order not to overtrain. First, aim for a 4:15 marathon, and then try to break four hours.
Muscle cramping may have been the result of inadequate training for your marathon effort. You will probably need more long runs and longer, long runs. Try to have two to three long runs each month.
A longer build-up with long runs may enable you to gain more experience running 21 or more miles. Taper to your last three long runs, which should not exceed 10 miles. Allow three weeks for recovery after your last long run. Run increasing portions of these runs at marathon goal pace (9:09 for 4:00).
Once a week, work on improving your speed, since you have a time goal. Base your speedwork on current 5K pace: running at 5K effort or slightly faster, building up to three miles of work.
If your 5K pace is 8:00, try this schedule: warm-up minimum one mile; 6x800 at 3:56 or 4:00; rest intervals at 2:00 or jog 200; cool down at least one mile. Or try 4x1, 200 at 5:55 to 6:00 with 2:00 rest intervals.
A third hard workout per week could be an anaerobic threshold run. This run would be about three miles at :25 to :30 slower than your 5K pace.
Be very conscientious with diet, rest and recovery to avoid overtraining.
Muscle cramps during long-distance running are often the result of sodium depletion. Anyone exercising in excess of three hours is at risk for running low on sodium, and the result can range from muscle cramping to more serious problems.
You say you are well-hydrated, but if you are drinking mostly water, your cramps may be the result of salt depletion. It is a good idea to increase your intake of sodium.
Use more table salt leading up to any runs over three hours, use beverages with electrolytes (like sport drinks) to rehydrate during races, and The American Running Association's Editorial Board Member, Randy Eichner, M.D. suggests carrying a salty snack like pretzels to eat about every half-hour during a race.
While salt will not guarantee an under-four-hour finishing time, it is very good insurance against muscle cramps.