By Dr. Antonio Parolisi
Neurophysiological considerations in the practice of stretching for "STRENGTH TRAINING"
The title of this article is undoubtedly provocative and contrasts many of the concepts presented in the world bibliography dedicated to sports and athletic muscular training over the last forty years.
The concept of stretching intended as a preparation for athletic performance and injury prevention is only partially true ... and as usual it is an extremely subjective condition and depends on the type of muscular work that is being performed.
When a muscle is stretched, the muscle receptors located in parallel between the fibers, the spindles, signal a state of stretching tension, causing a reflex-defense contraction that avoids the excessive streth that could cause a stretching or even an overstretching, or a tear in the muscle fibers; but if the muscle is first adequately heated with a proper warm-up and then stretched with appropriate stretching techniques, it will yield slowly and physiologically in the sense that it will increase its ROM (Range of Motion), or the mobility field of the articular district connected, giving the effect of a wider freedom of movement.
If the subject in question aims to train the force or otherwise to carry out series of 6-12 repetitions with a time under tension less than 50-40 seconds, with loads close to the ceilings, around 85-95% 1RM, practice of good old and healthy stretching, "could" be counterproductive.
I realize that the above can result to how much bizarre but the question is the following: if the muscle is lengthened to duty, the self-defensive mechanisms from stretchings are inhibited "in part" (I underline in part because an excessive stretching would cause the any tear); this extension will undoubtedly be advantageous in the case of endurance athletes or in any case of subjects who apply repeated gestures in elevated radius of action, such as dancers or martial arts practitioners, who need high muscle-joint flexibility to carry out their performance and also to protect themselves from possible accidents due to excessive stretching; "but" if the subject in question is an athlete who makes use of short and intense gestures with a recruitment of almost total maximum strength, this excessive articular and muscular flexibility, determines in part the functional loss of that famous reflex by stretching of the neuromuscular spindles which no longer induces reflex contraction, not allowing the muscle to recruit adequate strength levels.
If, for example, in the bench press with dumbbells, in the lower part of the movement, that is when the arm is parallel to the floor or even beyond, the pectoral muscle will reach maximum elongation, and it is indeed at this point that the stretch reflexes will cooperate in the contraction towards the phase of adduction of the arm, following physiologically the cycle of muscular contraction composed of a maximum active elongation, followed by a maximum contraction in the complete ROM. If, on the other hand, the muscle or muscle district has previously been treated with stretching techniques, the partially inhibited neuromuscular spindles will further increase the field of joint mobility, creating an increase in the difficulty of the return movement true adduction as the muscular stroke will be greater, therefore it will require greater strength for the same load as the previous one without elongation.
The increase of the ROM is not functional and this can even cause injuries when using loads close to the ceilings (85-95% 1RM), since the part of flexibility of the muscle obtained by stretching is not functionally usable with the same load as in other parts of the movement, because it is obtained passively and not because the muscle has adapted to the lengthening with the load. Instead it would be more productive to increase the ROM with exercises that determine good stretching of the fibers such as, distension with dumbbells for the pectorals, or pullovers for the back or the French press for the triceps, etc., preceded by a good warm-up and maybe as a second exercise in succession to fundamentals, such as Squats, Tractions or Bench presses. The aforementioned exercises perform the function of active and functional elongation, in the sense that the muscle extends throughout its range with a load, obviously following a correct execution technique, without tears or various compensations; this determines the functional increase of the force in those points of maximum flexion that will activate the stretch reflex, inhibiting them in part, therefore increasing the excursion but this time with a good recruitment also in those points where the maximum stretch occurs.
The above can be easily experienced by observing a subject who performs a series of pullovers or other stretching exercises; it will be noticed that with the progression of the repetitions, the shoulder will go more and more in flexion and that the ROM will be considerably increased towards the end of the set with respect to the first part. This, although it may be athletically productive from a muscular point of view, can be extremely dangerous for periarticular structures as it stresses joint capsules and ligaments, causing joint pain; so it is good to use such exercises very carefully, always working in non-pain. "NO PAIN NO GAIN" is absolutely not a good concept, leave it to the masochists of the sector ...
The part dedicated to stretching should be immediately after the training of those muscles that have worked, devoting a good part to the global stretching of the muscle chains, paying attention to the respiratory dynamics that will give greater sense of relaxation to the muscular structures, facilitating the blood circulation, previously compromised by the momentary ischemia induced by the pumping exercise, creating the conditions for a better recovery, helping to drain the muscle from the post-workout catabolites and reducing the DOMS, induced by the exercise, limiting the accumulation of hydroxyproline in the muscles, which together with other substances, give the feeling of soreness the day after training.
The above concepts are mainly aimed at strength athletes or subjects who use quite demanding loads like bodybuilders. For athletes in general, instead, the practice of stretching before training or competition is normally recommended to harmonize the athletic gesture and increase the ability to manage movements in space.
Ultimately, therefore, stretching is not the wicked witch who in many have believed at the beginning of the article but it is an excellent weapon to increase athletic performance and like all weapons must be used sparingly and scientifically; in the case of bodybuilders, powerlifters or athletes who resort to high levels of strength it is always better to practice it after the performance, while in other sports before and after it would be ideal ...
Good lengthening for everyone ...
