The Sedona Method is supposed to work regardless of whether you believe in it or not, so don't worry about your doubts. The Sedona Method has 6-steps to it (though it's not complicated). The first two steps are key to releasing.
The first is that you must WANT imperturbability more than you want approval, control, and security. You don't have to BE imperturbable you just WANT it more than you do anything else, at that moment. You might not be able to want imperturbability more than anything else all the time, but you CAN easily do it for just that brief moment in time when you are releasing.
The second step is to be determined to release and go free, no matter what. So you are pumping yourself up to get through that initial resistance (yes resistance to releasing resistance).
Then you have to find what want that resistance is coming from (3rd step). Is it coming from wanting approval, control, or security? The fourth step is to make it CONSTANT, because releasing is about MOMEMENTUM. When you aren't releasing you are suppressing and then it gets more an more difficult to release. The 5th step is to let go of wanting to control the stuckness. Let go of wanting to control not getting the result you want from releasing.
A release you can do for that is to say:
Am I wanting to change that resistance (or any feeling that you can't get to budge)?
Could I let go of wanting to change it?
The 6 step is each time you release you get higher and higher.
With whatever you are feeling at this point you ask yourself:
Could I release it and see if it gets any better?
Then just keep asking that question.
You doing a quick release just before you exercise is not going to work. That resistance is like your general pool of negative energy that makes up your DEFAULT vibrational set point. That's not just related to the Sedona Method or releasing. Many people have raised their default vibration by meditating, tapping, etc. etc.. It's like the more you've dig out in general, the quieter your mind is and the easier it is to release.
However, you don't have to have done a ton of releasing or mediating to get a specific result in one thing.
You just need to set aside A LOT of time for a long releasing session in order to get it all out. That's true for a lot of people who have been meditating and releasing for a long time.
You release until you are HOOTLESS.
Meaning you don't care about you resistance to running at all.
A brief releasing session on your resistance to running will just likely not have any permanent impact. You have to release all the way into the higher vibrations of courage acceptance and peace to get lasting results.
It's better to sit down with a pen and paper:
Do the now feeling releasing process
Do attachments and aversions
You want to do as many rounds of the likes/dislikes or advantages/disadvantages as you can until you literally can not come up with any more. If your mind just starts to wonder and become extremely unfocused, you have to get up and do some light exercise for 20 minutes then come back to it.
If you are thinking, oh this Sedona Method doesn't work, or meditation doesn't work, or tapping doesn't work, that RESISTANCE or vibrational set point will be there, regardless. It's all working with the exact same energy so you can't put the blame on any one tool.
So you should be able to take an afternoon, or a day or two and just sit down and knock it out .
I also caution you because with releasing you might find that running is not what you should be doing and instead it might be best for you to do rowing or resistance training etc. etc.. I guess you'll find out for yourself fairly soon.