The main goals of long runs are to improve our carbohydrate storage capacity and to become more efficient at using our fuel. The long run works by sending our bodies into crisis during those last few miles when our fuel supply is running low, which signals our bodies to adapt so that the next time we run long, our bodies are prepared to cope with that stress. When we take in a carbohydrate drink or supplement during training, it prevents us from reaching the decreases in fuel stores that lead to adaptation. Essentially, since the stress is reduced, the adaptation is reduced. -When Damage is a Good Thing
MY COMMENT: This well written article by Steve Magness poses some interesting questions about recovery, and optimal running performance. I'm always intrigued by "out of the box" training ideas.
Is it possible that long runs are more beneficial when you don't take carbohydrates? Yes! (see related post here)
The problem is every time you do this, expect a significant drop in performance during the latter stages of your run and perhaps a longer recovery. In addition, it's imperative that you practice fuel intake you'll be doing in a marathon. For this reason Magness suggests you alternate no calorie long runs and runs with fuel.
My training back in the 70s consisted of a heavy dose of 90 minute tempo runs (or longer), with a 2 hour plus jaunt on the weekends, and I don't remember drinking or eating anything, especially in winter! Did it help? The scientific evidence isn't clear on this one.
Although there are undoubtedly favourable metabolic changes after low-glycogen training, the results are rather mixed as to whether these changes translate into performance gains. -pponline.com
Here is another thought- let's say you encounter severe depletion on your every other week no carbohydrate runs, and that delays your recovery by one extra day. Over a period of a 16 week marathon build-up, you'll lose 7 valuble days of training.
Magness also suggests that antioxidant supplements reduce adaptation to training and therefore may limit the benefits. There are a couple of problems I have with this theory. First, isn't it true that immune system is suppessed for a period of time following a hard workout or race? I'm pretty sure antioxidants have never been found to enhance performance, but I'm also not aware of any studies reporting their use inhibits performance. I am not an expert, but doesn't antioxidant supplementation take some time to optimize free radical protection? I for one, am sticking with my two doses per day of Cooper Elite Athlete multi-vitamin and mineral supplement (see my previous post on the benefits here). I find it hard to believe that elevated C-reactive protein, a marker for inflammation following hard exercise, is a good thing.
The article also suggests delaying ice baths (if you use them) until the day following a hard workout giving your body's natural recovery process time to work. I find it funny that NIKE is touting their latest training toy, the cryosauna, a device that uses liquid nitrogen to cool down runners after workouts. They even flew one out to New York for Dathan Ritzenhein prior to the marathon, which to me makes absolutely no sense (by that time, his hard workouts were a thing of the past- it might have made more sense for Ritz to heat train those last few days!).
I don't know if Magness is right on with this or not, but my gut feeling is telling me this idea is also a bit of a stretch. If you tear down during a workout, your body repairs itself to become stronger. I believe the level of stress is probably the key to improvement, not the length of recovery.