Delayed onset muscle soreness (DOMS) occurs 12-24 hours after you performed a new exercise at too high of a volume or intensity that the body was not ready to handle. Can anyone relate to going for a random run with your trail running friends and the next several days you’re in so much pain trying to move that the idea of having a walker or a wheel chair is really appealing? That’s because of the repetitive lengthening of the quads during foot strike to break the knee. The forces generated in the quads are quite substantial (especially downhill) leading to small tears in the muscle and inflammation. Once you experience the soreness and live through it, it is best to keep up your running so that you adapt and never experience the pain again.
It is never OK to be so sore you can hardly stand up. This means the shock of the training stimulus was too extreme for you to handle, and you must seriously re-evaluate your routine. Your body is in an inflamed state and inflammation is NOT a state of health. Pushing yourself every workout to the point of exhaustion and failed reps leading to chronic soreness is absolutely a diseased state, and simply means you are failing to adapt to your training. If you believe in the dogma of “no pain no gain” stop, it is a flawed statement.
Mild to moderate soreness may be necessary at the beginning of a new training cycle, because the body is responding to the stimulus by adapting to it through increasing the structural integrity of the muscles and connective tissue. Personally I try not to provoke delayed muscle soreness with my novice clients, this is for both physical and emotional reasons (i.e. I want them to come back). For my well-trained clients sometimes muscle soreness happens during a day that was meant to push the limits, but always followed with an active recovery day and aerobic endurance training day until the muscles heal and have become more resilient to the stress.
Please comment if you have any questions. I’m happy to respond.