There are so many different definitions of flexibility. Some references interchange the terms flexibility and range of motion. Sometimes the word stretching means range of motion and vice versa.
The length of the muscle tissue and fascia is what I use to define flexibility. Flexibility is just one contributing factor to healthy and normal range of motion around a joint. Range of motion is more synonymous with mobility, a term encompassing overall joint integrity.
Stretching is the act of increasing flexibility, of releasing the knots in the muscle fibers to allow the length to occur and contribute to or maintain the healthy range of motion of the joint.
What about self myofascial release? I think that belongs under the category of stretching the way I describe it. Stretching includes the release of the knots, so that is important as well! These knots can restrict blood and oxygen flow, contribute to muscle imbalances and hinder normal healthy range of motion. Whether it is with a foam roller or massage therapist or contract relax stretching protocol, I think it's valid and it works.
I am not a clinical person. I don’t keep exact records of the precise number of sets, reps and weight I do with my clients, although it is simple for me to demonstrate improvements and results. The same applies to stretching as part of the personal training program. I do not measure joint range of motion with a goniometer. I think as personal trainers we can and should be able to see a lot of things with our eyes and feel with our hands. I eyeball the joint range of motion. I compare the active and the passive to what is “normal” and then feel what is happening as the limb is put into a position where the stretching muscles are being lengthened. If there are abnormal limits to range of motion, you have to feel what is limiting the range of motion. If it is the length of the muscle fibers, I help release or relax them, and I instruct the client to work to encourage and reinforce that range of motion through full body movements and strengthening of the opposite muscles.
Here is the deal. Most people are overweight and inactive. If I can help them feel better and not hurt them, then what's wrong with that? By the way, there is plenty of research that shows that stretching is effective at the beginning of the workout, only not if it is static. There is other research to support the notion of static stretching and not stretching at all or only at the end of the workout or only contract relax or whatever! All I'm saying is there are plenty of “experts,” and you could get research to support any theory you want. I do agree that stretching is unnecessary and even dangerous when joints are hypermobile and potentially unstable or when the passive range of motion is much greater than the active range of motion. But ultimately, you need to find what works best for you and your clients and know that this will change from client to client.
What about yoga postures? Aren’t you stretching some areas at the same time as strengthening others while staying strong at the core? Sure, it’s integrated and that, I believe, is probably the best way to do it – work the whole body as a unit. But I still think there is room for many different protocols and philosophies. People who say stretching isn’t necessary are right if the client does not live in 2005 and probably has a sedentary job or desire to live their lives in a functional manner!! I believe these clients could use a nice stretch to feel good and enhance results.