Recently, one of my athletes asked me “XYZ runs back to back 21K. He says it helps him. How does it help him? Is it good? Will it help ME?”
Whenever you see a runner or any endurance athlete doing something different or new, the first thing that more often than not comes to mind is whether you should do it, whether it will help you improve. This is what I call the Copy-Cat Syndrome. However, before taking a call, be sure to consider a lot of different things, because you can be 100% certain that you are not seeing the big picture. Just because somebody is doing them does not mean its good, has a favorable risk-reward ratio, is suitable for you, or is the most efficient.
For starters, you do not know everything about XYZ. How consistent is he? Is he able to do the next workout properly as per plan (he has a plan right??!!) or is he so knackered from the back-to-back runs that he does nothing for the next whole week? For all you know, running back to back 21K may be all the training he does!What about other life stressors? Does he have a full time job? High stress job? Long hours? Long commute? Does he have any responsibilities at home? Kids not letting you sleep? Guests who wont leave?How old is he? A 25 year runner may be able to handle this, but a 45 year old will have a lot more difficulty.
What is his running background? Is he a relative beginner or has he been running for years?
What is he training for? He may be training for a full or an ultra. Are you?
Further, the proof is in the pudding! How is the performance of XYZ? Has his race times improved? And if you could get the same improvement without the risk and stress of back to back 21Ks, wouldn’t you choose the alternative?Yes, me and the other Motiv8 athletes training for Comrades did a lot of such back to back 21K runs, but it was always a tight rope managing fatigue and keeping injuries at bay. I would not do such runs nor prescribe them to athletes unless absolutely necessary and always after looking at the whole picture as it applies to the specific athlete and his/her circumstances.