“I was 13 weeks into my first marathon training when I over-stretched and either strained or tore the ligament on the bottom of my foot. I took 1 week off, tried to run, found it hurt after my run, took another 4 days off and attempted to run 10mi today and stopped at mile 3, because I could feel the slight bruised feeling on the bottom of my foot return. I have completed 18 miles prior to the injury and would so much like to get back to running. I am training for the Marine Corps Marathon in late October, so I know I have time (I hope) to recover and still be OK to run in the race. My question is, when I cross-train (biking or swimming), how long do I go for? What would be a comparable schedule? Can you suggest a schedule that will hopefully best maintain my cardiovascular conditioning?”
Cassandra, first the bad news. There is no real reliable translation of cross-training equating to running miles. Calories expended can be determined by exercise or activity and heart rates vary widely by discipline. In any case neither of these measures in cross training will help you in preparing to run a marathon. You are training to run a marathon not swim it and not bike it (or elliptical it for that matter). This is not as much an issue of “cardio” – heart and lungs — as it is a neuromuscular issue. You need “running” muscles to function efficiently. That is not to say that other training is useless. It is to say that there is no direct translation of yards swimming to miles biking to miles running.
The good news is 10 days is not to long of a time off, even though this is happening at an inopportune time (then again when do any injuries happen at a good time?). The other good news is that there is training you can do that will maintain your general condition.
The most research documented cross-training is aqua running. Performed in place of workouts for short periods of time (a few studies show 4 weeks) little conditioning is lost. The key is to do aqua running in a high quality interval fashion, not steady state. Either using a waist float to suspend you in the deep end of the pool or running on the bottom of the pool work. Workouts should last a minimum of 45 minutes. Another real bonus is that aqua running can be done daily! It doesn’t take as much out of you as conventional interval work on a track, which often necessitate an easy day or two before another hard go.
The second cross-training that has shown some cross effects for conditioning is cycling. However, once again, it appears that hard interval type workouts are the key: hill intervals, sprints, etc. just as you might do with you running. Hours upon hours of cycling at a steady state may or may not be as beneficial. So, my advice is that when you ride: ride hard.
If you can run one day a week, make it the longest run possible without further aggravating your injury. That will be the one area that you’ll need to shore-up… endurance. On that day, I would also strongly advise that you run as many miles as possible at your goal marathon pace. Running at goal pace will get you more efficient at your pace.
Ideally, you’ll be able to alternate running a day with one of these two types of cross-training on other days until you can handle getting back on terra firma full time. You’ll be on the tight-rope perhaps until race day – trying to get this injury 100% resolved while getting adequate training in. Read your body.
Drop us a line and tell us how it goes.
Coach Dean Hebert, Tempe Arizona
Contributing Editor, Running Advice and News