Just as a casually competitive runner can exercise more than three or four times a week without running more than three or four times a week, a serious competitive runner can exercise twice a day without always running twice a day. The question is, should he or she? While there are many examples of very successful runners who run 14 times a week and never cross-train, I believe that in most cases, runners who train nine or more times a week are better off running seven times and lifting weights and doing plyometrics two or three times than they are making every workout a run.
In fact, there’s research proving this. In a famous Norwegian study, elite runners improved their 3K race times by replacing 30 percent of their running with plyometrics—not adding plyometrics to the running they were already doing, but replacing a chunk of their running with plyos. Based on such evidence, I advise runners who train nine to 10 times per week to perform two or three strength/plyo workouts and run the rest of the time. There’s no need to do strength and plyometrics training more than two or three times per week, so if you add any workouts beyond 10 per week, the rest can and should be runs or non-impact cardio alternatives to running such as cycling.
What’s the absolute maximum amount of training any runner should consider doing? Many elite runners thrive on a schedule of two runs per day every day plus three strength/plyo workouts per week. If you can handle all that, more power to you!