Q. Just how much truth is there in "No Pain. No Gain"?
A. Tricky question. Generally speaking, there is little truth to this old saying - and believe me, Physical Therapists didn't make that one up!
The fact of the matter is that most new exercises will cause muscular discomfort 24 to 48 hours after it is performed. This is termed "Delayed Onset Muscle Soreness" or DOMS.
The discomfort will typically subside rapidly (with in a couple of days at the most) and if it doesn't, you've probably over-done it.
There are some cases, while in Physical Therapy, discomfort is experienced - and even mild to moderate pain - but your therapist will explain to you what to expect, and will guide you through the program so that the "hurt" does not translate into "harm".