One thing that I am passionate about as far as my industry is concerned is that we have guidelines that we can adhere to as far as fitness goals are concerned.
Flexibility is a component of fitness.
As with other aspects of fitness, there are scientific guidelines/principles related to flexibility that we can adhere to in order to achieve a desired outcome.
We tend to use the FITT principle when we are designing an exercise program for our clients. We also consider the SAID principle. (Specific Adaptations to Imposed Demands).
That being said, if the outcome is increased flexibility, one must first ask him/herself:
What type of stretch will I used to reach the goal of the client.
Will you be using:
1. Static stretching
2. Dynamic or ballistic stretching
3. Slow movements
4. Proprioceptive neuromuscular facilitation (PNF) techniques.
After you have decided the type of stretch or the methods of stretching you will utilize (and this dependent upon the goal of the client), you can then manipulate the variables (FITT) based upon your client’s goals in addition to remembering you only get what you train for (SAID). And in your case you are training for flexibility.
Now ask yourself the question you posed to the forum. Somehow, I believe, that after you think about it you will come to a fantastic conclusion as to whether “one set of stretches is sufficient” when one is “training for flexibility.”
Thanks for your questions and I look forward to our continued interchange.