Is a cross-training kilometre exactly the same physiologically as a running kilometre?
Nope, but intense cross-training for an hour can elicit the same aerobic benefits as a training run. Therefore, you can boost your weekly mileage with intense cross-training.
A basic formula for cross-training: 60 minutes at or above 70 percent of your maximum heart rate equals a 8km run. Use this formula during the winter when conditions make it difficult to keep running mileage high.
Because of the low-impact nature of most cross-training activities, injury-prone runners can beef up their mileage using this formula without increasing their risk of injury.
In the following two case studies, both Lisa and Dave used cross-training mileage to become better runners.
Cross-training through injury.
Lisa, a good cross-country runner, had been injured in a car accident. When her injury had mostly healed, she was able to run but could maintain only about half of her pre-accident mileage. Working out on either an elliptical trainer or a stationary bike for an hour a day, Lisa increased her cross-training mileage quickly.
More importantly, the supplemental workouts enhanced her aerobic fitness, which allowed her to increase her actual running mileage. And even though her total mileage skyrocketed to 180km per week (80 cross-training kays plus 100 running kays), Lisa’s morning resting heart rate remained the same, which indicated she was not overtraining. By the end of the summer, Lisa had the strength and energy to lead her varsity cross-country team to the national title.
Cross-training to lose weight and boost fitness.
After four years of competing for his varsity cross-country team, Dave took a two-year break from running to live and work in Spain. When he returned from Europe 13 kilograms heavier, he tried to run again and found that the extra weight made his knees and hips hurt. That joint pain, coupled with his lack of aerobic fitness, made it difficult for Dave to run long enough to lose the weight.
Over a three-week period, Dave gradually added up to an hour of cross-training per day (elliptical trainer, stationary bike and pool running) to his 30- to 45-minute daily runs. As his weight dropped and his fitness increased, Dave could run farther and faster with no pain. After several 80km weeks (40 cross-training kays plus 40 running kays), Dave dropped the extra weight, then continued to cross-train twice a week for enjoyment and additional weight maintenance.
- Choose workouts that are closest to running in terms of muscles used and aerobic systems taxed. Good options include elliptical trainers, cross-country ski machines, stationary bikes and water running.
- When cross-training, keep your heart rate at or above 70 percent of your maximum heart rate (220 minus your age) most of the time. In other words, you should be working hard and sweating a lot.
- Check your morning heart rate regularly. An elevated morning heart rate is a sign of overtraining, which can occur if you add too much cross-training too soon.
- Combine cross-training with running to maximise running fitness with lower actual mileage. You can substitute 25 to 30 percent of your weekly mileage with cross-training.