Crossfit endurance

According to Dave, my organizational guru and a budding disciple of the Crossfit religion, endurance sports produce oxidative stress, which can have an incredibly bad impact on the body. This is causing me some concern as I plan my 18 mile run tomorrow in preparation for the December 7 marathon.

Scientifically stated, oxidative stress is caused by an imbalance between the production of reactive oxygen and a biological system's ability to readily detoxify the reactive intermediates or easily repair the resulting damage. The main thrust; 50-year old marathoners and Ironpeople look very old and wasted (or meth addicts according to this video) because they have spent 20+ years poisoning themselves with reactive oxygen and can't repair the resulting damage.

The solution according to some is a Crossfit approach to exercise. Rather than going long and slow for 1+ hours or more, Crossfit is quick, explosive and hard workouts such as doing 100 pullups, 100 pushups and 100 situps as fast as you can. There are even workouts tailored just for endurance athletes. I haven't read everything yet to be informed but I think the claim is on no more than 60 minute training runs, a Crossfit God completed a 50 mile run by focusing on the explosive workouts.

I consider myself somewhere in the middle between Crossfit and 100 mile/week running fanatics since I alternate lifting one day and running the next. However, Dave and other Crossfitters claim a focused Crossfit program is way beyond normal workouts. After I finish the marathon, it might be time for me to end the 25 year exercise rut.