To many people, stretching is something that is good though it is often not done as frequently as they will like. But is stretching really good for you? Is it even helpful?
Some experts, including the inventor of kinesio tex tape himself, have strong sentiments against stretching. Some even say stretching is outright bad for you and often times quote the example of how animals as 动物 (moving bodies) rarely hold a stretch pass a couple of seconds before quivering their body and carrying on with their movement; some say that holding a stretch past a couple of seconds introduces fascial creep which compromises muscular activation; and there will always be someone describing how deep stretching and stretching past "R1" to absolute end range will overstretch joint structures like joint capsule and ligament to cause many joint problems.
Then there are also people who strongly advocate for and actively prescribe stretching as a primary means of self-therapy. It is so common in Singapore to see conventional physiotherapist prescribe stretching exercises as the largest (and probably the most important) component of the bring-home-exercises for patients with musculoskeletal issues. Then there are some (but I'm sure it's not all) yoga instructors who feel the more flexibility one has, the better.
So which camp is right? To stretch or not to stretch? Since the academic literature demonstrated mixed results as to the goodness of stretching, I'll say it depends. It depends on the individual, for what use it is for, and how it is being done. YLM Sports Science has a nice infographic summarizing the review of the evidences in stretching.
One has to understand that stretching, to many sedentary individuals, is a way to visit the joint range of motion that they don't visit often. It is therefore a method to increase or retain joint range of motion (if it does) for a given purpose. For example, the split leap (gymnast and dancers do so well with), ordinary folks like us who rarely visit the extreme ends of hip movement in activities of our daily life will likely not be able to do it immediately. Even the front split, an important pre-requisite for split leap, does not come naturally to the majority of us such that we will have to work our way towards it. Stretching the hip and legs progressively for this purpose will serve us well in bringing us into the hip joint range of motion we seldom visit in our daily life for the ultimate end goal of a split leap if that's the desire.
In another example of bending down to pick up stuff from the ground, when the individual is highly sedentary and seldom work into folding the hips, there is not a high chance that the person can and will automatically be able to use a clean hip flexion for the movement. Instead, folding at the waist and through the spine to reach down is more likely, though it may not be as spine sparing as we will like it to be. Working into stretching the posterior hip with each knee straighten and knee bent, in this case, will offer us the chance to work into forward bend mechanics that transfers the load into the posterior hip and away from the lower back. So stretching is a good thing, right?
If used appropriately for the individuals when truly needed, yes; the best part is it can be done alone when the individual is well acquainted with the movements involved. But before we even look to stretching as one of the means to make up for the sedentary lifestyle, it may be wiser to ask why are the muscles in that area so tight in the first place? Or why are the muscles not giving in a certain position when it should?
You see, it is easy for us to write it off as "the muscle is just tight", or that "he is a very tight person to begin with". What is harder but definitely more effective at dealing with the mobility problem is to ask what is causing the tightness in the first place? Is it the body's perception of lack of stability at the joint or surrounding joints that it resorts to rigidity to feel safe? Is it a physical development, like a degenerated joint capsule that is causing the body to want to lock down the area so there will be less perceived future damage to the joint capsule? Or is it repeated/prolonged movement patterns which we do (like sitting down) that causes the body to be ever ready to activate the muscles and not let go when they should? Or is the person too much in a stressed state that the body's fight-or-flight system is causing tension to be perpetually held in the muscles? The causes for the muscle tightness may wildly differ but it may manifest itself as the same symptom of muscle tightness.
So short of speaking to a professional to figure it out, what do you do? Well, you can stretch the hell out of the muscle but the muscle will likely only stay lengthened for a short duration after stretching or as long as you are stretching frequently and consistently. Or you can try to work at the root cause of muscle tightness. For start, one can be less sedentary. Moving more in different manners, but with control, will afford you the opportunity to visit joint range of motion you usually do not visit. Then you can always try to work on appropriate joint centration to help the body perceive less "risk" in movement. And lastly, you can work on good belly breathing to help deal with the modern stressful lifestyle and help the body release the tension it held throughout the day. If the cause of the tightness is truly structural, there is more work there; some professional help, be it medical or fitness, will likely be beneficial.
Back to the example of bending down to pick up stuff from the ground, in a bid to increase hip flexion mobility in standing position, we may possibly look at how the foot and ankle move in gait. Since the ankle movement affects shin bone rotation (in the transverse plane) and since the hamstrings have attachments on both sides of the shin just below the knee joint, it can contribute to the control of shin bone rotation and therefore ankle movement from proximal to distal. It is not the most efficient way to help the ankle move well though it is one of the strategies available to the body. Working at the foot and ankle level may be helpful in this case. Or we may possibly look at the lower back stability that may cause the body to want to shut down the hamstring to have the pelvis and therefore the lower back locked down to provide "stability". Working on good abdominal breathing and bracing in this case together with educating optimal seating posture will probably go a long way in helping the posterior hip musculature let go a bit.
At the end of it all, be it stretch or no stretch, it's always good to ask why is it that way in the first place or why is it tight? I do love a good stretch nonetheless and do see much value in stretching when appropriate; the academic research does support stretching for increased function and decreased pain in chronic musculoskeletal pain anyway. It's just that I prefer to work at the root cause, rather than the symptoms level, if I do find it. And yes, I will love a good fascial stretch therapy session done on me, instead of me doing it on others because it is such a good way for me to breath and relax.
Progressing your quality of life,
YB