HI Bruno - I looked at intuflow.
So there are movements that he is doing that would harm me in my present condition (at 33-37 seconds, the knees are torquing in a manner that will [increase the likelihood of]crush* the medial meniscus over time or in a moment of adequate force; a resolution to this may be i) to pivot that foot during elbow strikes, this also fulfills the potential of the strike, or ii) use the waist entirely for rotation, have no motion/force changes transmitting in the legs). Other motions that would harm me in my present condition are the rotator cuff circles at the end. There are tendons that can hang up on the acromion here.
That said, the founder of the program suggests intuition, which I could take to mean "based on one's own personal experience practicing forms, listening to body, and responding healthfully". It is clear that he has changed his life and faced challenges to meet with his conveyed sense of well-being. If the program works for you, that's great. I would encourage doing whatever gets you started, then the process goes and goes and goes. To not balance the mental with the physical is to overvalue the mental states wherein a sense of permanent self takes form and abides and occludes other aspects of living as a changing being in a of a changing place (that can be termed anatta and anicca, if it is useful).
However, if one considers physical exercise to be a false "propping" up (out of recurrent "dark night symptoms"), then I think a sense of defeat will occur and prevent effort (and there is a pleasure that arises in contrast to having to do something by deciding to not do anything; this feeling can convert a sad moment ("I am blue sitting on this couch right now"), to an averse aroused moment ("What?!? The hell if I am going to exercise this body"), to a happy moment ("wow, I am pleased to be sitting on this couch right now and not having to exert myself"). That cycle can happen in seconds. To avoid a sense of laziness, one can replace sitting on the couch with a "noble" or "commendable" exertion, like studying or meditating, while still avoiding the other exertion (this maintains this aversion and creates pleasure and "props" up a circle that will probably wind back to dark night symptoms without some exertion...). I do not know "future" (and any potential future meetings with "dark night symptoms"), but I would say to the concern about continually needing to prop oneself up that, for me, it has been [and is] a process of effort and attention applied over and over again that has resulting awareness and that those efforts have been and continue to be worthwhile.
One part I especially appreciated in your hyperlink to intuflow was the section showing him rotating his hip joint with the foot and knee in flexion. When the foot is in flexion, it is harder to strain the medial collateral ligament (notice that the degree to which the foot can be rotated medially is smaller when it is flexed than when it is extended with pointed toes), which (of four ligaments around the knee) has a high rate of injury, surpassed only by the ACL (which cruciate ligament is often torn from over-bending the knee). He may have other reasons for doing this motion (like protecting the ankle components), but protecting the knee while the hip is circling stood out to me. (The hip rotation, like the neck circles, is not one I would do at present, though I may make these a goal in order to test their effects personally. Thank you for the link).
If I could simplify stretching and training, I would say start with your interests (or find a physical interest that is inspiring or beautiful to you) and cultivate excitement-dedication concentration on that challenge. Consider using meditation to visualize yourself doing this activity well and in detail.
Outside of meditation and concentration, place the mind everywhere present, e.g., taking a pee, the mind is with all locations of sensation. In this way, when you stretch, you may be immediately aware of the body's communications (about the nature of the stretch) because you will be well-trained in attention of actuality via so-called habitual moments (like cooking, eliminating, lying down to sleep, walking, stepping, blinking,etc). The body then stands a chance of informing the mental faculty (as opposed to the mental faculty assuming, bullying or just ignoring the physical signals), I would guess from your posts of actualism/buddhist mindfulness practices that you're probably quite capable of sustaining this quite well. (Although, this mind-with-whatnot (mental faculty on actuality) can be over-done if the change of mental faculty's use is taken too zealously and not increased in little, reasonable bits.)
One learns form of an exercise, though, so that if attention wanders, the body is not placed badly for an injury. So the preceding paragraph has a high standard for attention which can create tension. Thus, I'd read about the form of a stretch (or exercise) carefully, go slowly, and not rely entirely on the tool of expert attention. Even with expert attention and preparedness, surprises occur. Good form in a stretch also allows for an unloaded mind to join the muscles in being comfortably active.
If you use that link to Ray Long (I stick with a source as long as that source is answering my own experiential questions and, thus, obtain a bit of consistent learning from that source), you may read portions of the book for understanding of anatomy and stretching form. With the knee, for example, a twinge experienced now on the inner knee (as known by personal experimentation and well-trained awareness) may point you to the medial collateral ligament. Maybe there will be the learning of something like, "Ah: the knee is misaligning
over with the big toe, versus the 2nd or 3rd toe!"
(Knee cap should not extend past the heel bone, unless you are really certain that your ligaments can handle this over time. Placing knee beyond heel with force is a great way to tear the ACL).
I learned to apply a stretch and its opposite, and that has worked for me. For example: forward bend, back bend, twist and opposite twist. Therefore, I might start with
uttanasana (or seated forward bend in a chair if my hamstrings have a twinge), then do something like
setubandha (or salabhasana, pages 38-45 in Long's Volume 3, or
here in yogajournal.com ), then bull seat prep for gluteus and latissimus dorsi. If all is well in my body (meaning no twinges and that the stretch is comfortably active, then I breath deeply with the pose for two minutes. If there are any twinges I back off until there is no twinge in the stretch.
I also make sure the agonist muscles in the stretch are generating heat (maybe think of a working muscle as being in "agony") and that the antagonist is experiencing the comfortably active stretch. The muscles that are contracting to become smaller are the agonists and the muscles that are technically contracting by expansion are the antagonists (the antagonist is the one getting the common parlance "stretch" - though the stretch can also be
strengthening...getting a little too detailed here, but you will see the effect in toning). I have no affiliation with Ray Long, yet
here is another page from his business about this.
All of this increases my range of motion (flexibility), strength and support around the joints, and non-compression in the joints.
If you are doing explosive activities (sprints, jumping) then when you stretch in longer-held postures will vary. However, explosive use of muscles (such as ball-of-the-feet-joyous springy jogging), in my experience, benefits from longer-held, deep breathing postures, but that I do not stretch like this right before I intend to have explosive energy.
If I think of more (with fewer words) I'll let you know. I am interested in learning of your exploration because of your past posts about explorations and attention.
Cheers.
*medial meniscus is often injured by wearing down. So a person may have a great teacher of a sport or form for years. Pay attention to how that teacher may rub the knees or demonstrate postures. They may be heading towards surgery to clip the frayed fibers of soft cartilage. This fellow of intuflow has another video on protecting the elbow joint from common injury, so hopefully his knees and advice are good.
[edited: typos, syntax, possible clarity]