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mileage posted: Fri 2011-10-28 16:36:38 tags: fitness
Been pushing a little harder/longer on ab workouts on my off-days. Why do muscles feel sore a day or two after a moderate workout? Because they literally suffer a certain amount of "micro-injury". First, a certain amount of lactic acid damage inflicted by "pushing" muscle metabolism, that is, metabolizing glucose faster than oxygen can be supplied to convert it to pyruvic acid instead of lactic acid. And second, tiny ruptures or "fraying" of the muscle fiber structure.

This is the bodybuilding principle of "overloading". Within bounds, the controlled micro-injury is desirable. The healthy body has a great capacity to repair muscle tissue - much more so than, say, neural structure (although contrary to popular misconception, even the nervous system has some capacity to regenerate). The micro-injury condition prompts the body to compensate to protect itself from future potential muscle strain, not merely replacing damaged muscle tissue, but building more than it started with. Hence the adage "no pain, no gain".

Moderation is the watchword, of course; excessive strain risks not only disabling macro-injury, but a normal Skinnerian psychological aversion to stressing that muscle, which may inhibit rehabilitation and interfere with performance even after complete physical recovery.

My treadmill sessions tend to follow this pattern: Warm-up at a moderate-brisk walk (~3.7mph), step up to an endurance pace (~5mph) or shoot for speed (currently 7mph), drop back to recovery pace (3.5mph), walk until I've cught my breath and cooled off a bit, repeat. If I measured strictly on first- and second-mile time I should by right have dinged the 45-minute / 3.3 mile goal by now, but in that last mile I invariably find myself realizing after an extended cooldown that I'm not going to make the time goal.

3.3mi/45 minutes is only 4.4mph. I can power-walk faster than that, although I think that would be insufferably boring for 45 minutes straight.

Session #28 (per twitter): 3.3 mi / 45m42s \o\ over a full mile at a jog \o/ 3/4 lap at 7.1mph /o/ -o| 7oº