Scientific support for slacking offApril 25, 2007
Ever since incurring extensive muscle damage at the Mad City 100K, I’ve been wondering why my training didn’t protect me from this trauma. My tentative conclusion is that I may not have allowed my muscles to heal completely in between my long-and-hard runs, meaning that I may have gone into Mad City with a bit of residual damage that was exacerbated by the race itself.
So how did I arrive at this conclusion? Basically, I looked at a bunch of scientific journal articles concerning muscle damage and tried to relate their findings to my own situation (a general approach I call Research-Based Coaching).
The most interesting point I noticed in the research literature was that both recovery from and protection from muscle damage can occur over surprisingly long time scales. One study found microscopic evidence of incomplete healing in calf muscles 3 to 4 weeks after a marathon race (Warhol et al., American Journal of Pathology 118: 331-9, 1985). Another reported exaggerated heart rates while running and impaired jumping ability — most likely due to muscle damage — that persisted for 2.5 to 3.5 weeks after a 90K race (Chambers et al., Journal of Sports Science 16: 645-51, 1998). A third showed that as little as 25 minutes of downhill running can elevate markers of muscle damage for ten days or longer (Koller et al., Journal of Sports Medicine and Physical Fitness 38: 10-7, 1998). But what really amazed me was that, once muscles recover from a single bout of eccentric exercise (in which the muscle fibers lengthen while attempting to shorten — a normal consequence of running, but especially downhill running), the damage is reduced after a similar bout 6 weeks later (Byrnes et al., Journal of Applied Physiology 59: 710-5, 1985) and in some cases up to 6-9 months later (Nosaka et al., Medicine and Science in Sports and Exercise 33:1490-5, 2001), although the protective effect does gradually taper off during this multi-month period (Nosaka et al., Canadian Journal of Applied Physiology 30: 529-42, 2005).
While the last two studies focused on the biceps rather than leg muscles, the overall picture that emerges from articles like those cited above is the following. Muscles may take several weeks to recover fully from intense, damaging exercise, but this recovery process includes adaptations (the specifics of which I haven’t researched) that then help protect the muscles for additional weeks or months afterwards.
The implication for marathon and ultramarathon training is that extremely hard, muscle-shredding workouts and races should be separated by at least several weeks. Undertaking these efforts infrequently should allow complete recovery between them while still stimulating adaptation and enhancing protection during subsequent workouts/races.
Unfortunately, my schedule leading up to the Mad City 100K included a very hard, long road run every 2-3 weeks. On January 27th, I did 36.6 miles at a pace of 6:23 per mile; 3 weeks later, I did 41.5 miles at 6:22/mile; 2 weeks after that, I raced the Caumsett Park 50K at 5:57/mile; 3 weeks later; I did 29.3 miles at 6:24/mile; and 2 weeks after that came Mad City, where my pace was 6:20/mile at the start … and 8:20/mile by the end.
So I guess I should try trashing my muscles less frequently — perhaps by spreading my mileage over a greater number of runs and/or taking it easy on some of my long runs. That idea seems particularly appealing right now, as I sit here rubbing my quads — which are still sore from last Saturday’s trail run with Jurek — and looking ahead to the Miwok 100K on May 5th. After Miwok, let the slacking begin!<