Soreness is a funny thing, like a love/hate relationship, athletes love the feeling after a good workout, especially when it persists in the form of aching muscles for days after. Yet, you can balance that appreciation with the complaints of being unable to practice at full speed, or even sitting down to use the restroom. So is it always good to be sore? One thing is certain, if you haven’t done a sport or certain movement in a long time, being sore is just an indicator of certain muscles being used again. If you’re no novice to sport or training, then soreness has a much more complicated answer.
Soreness in the muscles generally occurs the day after training, usually peaking about 48 hours, hence the scientific term of Delayed Onset Muscle Soreness (DOMS). This soreness indicates muscle fiber damage caused by eccentric contraction. Eccentric contractions occur when the muscle is being lengthening, causing greater damage to the structure than other types of muscular actions. This contraction type can be seen best in decelerations, stopping quickly to change direction or slowly lowering yourself into the lunge position.
A 2001 study out of Monash University in Victoria, Australia was the first study to show that eccentric exercise increases the muscle’s optimal length of contraction. This effect on muscle occurred because sarcomeres, the contractile unit of muscle, were added lengthwise to allow operation at longer lengths. So you just made your rubber band longer or your hamstrings in this case, by emphasizing eccentric contractions. Perhaps, the most exciting finding was these adaptations remained even beyond 10 days. Dozens of studies have also show the beneficial effects of eccentric exercise on tendonitis, which makes sense, because this soreness will elongate muscle length to take stress off of the tendon.
So shouldn’t we all be getting sore every time? Not so fast. If you need more TIME on the ground (see Sparta Point 1/27/10), then focus more on exercises that target the lowering aspects of a movement to improve muscular compliance, or length. We use single leg movements, like step ups and split squats, because the relative instability forces a slower descent to emphasize the eccentric phase. Another option is slower descents while squatting, called negatives, and of course, any of these lifts’ eccentric portions are further stressed by just adding more weight!
If you need RATE, or quickness, even FORCE (see Sparta Point 2/2/11), then soreness may not be as helpful, as stretching out a loose rubber band only makes it more flaccid, not to mention easier to tear.