cool. i found this write up by christian finn concerning soreness
Facts and fallacies about muscle soreness...
When it comes to deciding how often you should train, a common rule-of-thumb is never to train a muscle that's still sore from a previous workout. However, a lack of muscle soreness doesn't tell you whether a muscle has recovered completely. In fact, the damage can persist even when the ache has gone away.
Muscle soreness
A good example comes from research carried in the Journal of the Neurological Sciences [1]. In a group of untrained men, significant soreness was evident for up to three days after exercise. Signs of muscle damage in the blood were higher for up to five days. Muscle function was also impaired for five days.
However, while other symptoms of exercise-induced muscle damage clears within a week, damage to the neuromuscular system (the "chain of command" that transmits signals from the brain to the muscle) lasts for 10 days or more — in untrained men, at least.
Changes to the "efficiency" of your neuromuscular system are one reason why you gain strength very quickly after starting a resistance-training program. In the early 1970's, for example, researchers showed that 100 days of isometric exercise led to a 90% increase in muscle strength. However, there was only a 25% increase in muscle size.
If you do want to avoid feeling sore after exercise, the best way is to ease your way into a new training program gradually. After just one bout of exercise, the repair of muscle damage can take up to two weeks. In the case of extreme forms of exercise such as a marathon, signs of muscle damage last a lot longer. Once the repair is complete, the muscle can tolerate the same task with less damage and faster recovery. Stretching, commonly recommended as a way to reduce muscle soreness, actually has very little effect.
While over-the-counter pain killers (such as ibuprofen) can ease the soreness that manifests itself after a tough workout, they're not as effective at restoring muscle function [3]. One of the ways they work is to suppress the synthesis of substances known as prostaglandins. However, these very same prostaglandins also have a profound effect on muscle growth. In other words, while they can control the pain, regular use of some pain killers could put the brakes on muscle growth.
Of course, if you're constantly sore, the best thing to do is reduce the amount of training you're doing. However, muscle soreness is not generally a good indicator of exercise-induced muscle damage [2], and isn't always the best way to decide how often to train a muscle group. Constantly training a "damaged" muscle can easily lead to a state of overtraining, where you make little or no progress despite the hours of work you're putting in at the gym.
References
1. Deschenes, M.R., Brewer, R.E., Bush, J.A., McCoy, R.W., Volek, J.S., & Kraemer, W.J. (2000). Neuromuscular disturbance outlasts other symptoms of exercise-induced muscle damage. Journal of the Neurological Sciences, 174, 92-99
2. Nosaka, K., Newton, M., & Sacco, P. (2002). Delayed-onset muscle soreness does not reflect the magnitude of eccentric exercise-induced muscle damage. Scandinavian Journal of Medicine and Science in Sports, 12, 337-346
3. Tokmakidis, S., Kokkinidis, E.A., Smilios, I., & Douda, H. (2003). The effects of Ibuprofen on delayed muscle soreness and muscular performance after eccentric exercise. Journal of Strength and Conditioning Research, 17, 53-59
