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Sacral neurons reassigned to sympathetic
The autonomic nervous system regulates the function of internal organs such as the gut. It is divided into sympathetic and parasympathetic subdivisions, the “yin and yang” control mechanism for stress responses (fight or flight) and homeostasis (rest and digest). The sympathetic and parasympathetic tend to work antagonistically. Sacral autonomic outflow is traditionally assigned to the parasympathetic division of the visceral nervous system—as part of the “cranio-sacral outflow”. Published November 2016 in the Science journal, Isabel Espinosa-Medina and colleagues from France used anatomical and modern molecular analyses to show that the autonomic motor neurons in the sacral cord share similar characteristics with the sympathetic motor neurons in the thoracic cord and not with the parasympathetic motor neurons in the hindbrain.
Dr Peggy Mason, a Professor of Neurobiology at University of Chicago wrote on her blog : “The crux of the change implied by reclassifying sacral autonomic motor neurons as sympathetic is that two functions, hitherto classified as parasympathetic, are in fact sympathetically controlled: Voiding (both urine and feces), and Sexual arousal (including erection in males).
So, what does it all mean?
Til Luchau, a massage educator and myofascial therapists said that this has implication to manual therapy approaches such as pelvic lift technique, craniosacral therapy, and trauma-informed approaches, which was supposed to “balance the parasympathetic nervous system”. The Big Question is does this change how we should work? Til said that if we could correct for confirmation bias (and we can’t, at least not by ourselves), we could say that if the old methods work, then maybe we just need to explain them differently. If people seem to get calmer with a sacral hold technique, for instance, then it is presumably doing what we want it to, even if we need to update our theory about why it seems to work. A rose by any other name, after all, smells just as sweet. Or so they say. But since we’re all prone to look for the results we expect to see, I wonder what will happen if we start imagining that we’re affecting sympathetic function (instead of parasympathetic function) with our pelvic lifts, sacral holds, etc.? Are there new possibilities that this shift opens up? For instance, can we up-regulate via a pelvic lift, as well as down-regulate?
Massage and post-exercise recovery: the science is emerging
Massage as a post-exercise recovery for athletes is not new, and new scientific findings support this, according to Thomas Best from University of Miami and Scott Crawford from the University of Nebraska in an editorial published in the October 2016 issue of British Journal of Sports Medicine.
The scientific literature on post-exercise massage in the last decade has provided a plausible biological explanation. Clinical studies have shown that massage mediates leucocyte migration and attenuates the inflammatory response to exercise, as well as decreases pain, muscle tone, and hyperactivity. Research studies have shown that massage mediates molecular processes linked to inflammation, specifically by decreasing nuclear factor κβ (NF-κβ), various pro-inflammatory cytokines and tumour necrosis factor-α. The demargination (process of neutrophils entering the peripheral circulation or circulating pool from marginating pools) of leucocytes is hypothesised due to increased peripheral blood flow and blood perfusion. Animal studies showed significant improvements in peak isometric torque recovery from intense eccentric exercise following four consecutive days of massage. It has also been shown that massage initiated immediately after exercise and massage delayed by 48 hours were both effective in reducing muscle oedema and decreasing the number of damaged muscle fibres compared to exercised, non-massaged controls. These investigations suggest that the reduction in inflammatory cells and pro-inflammatory cytokines by massage can mitigate secondary injury associated with intense exercise, thereby reducing tissue damage and accelerating recovery.
Studies also showed that shorter sessions of massage (5–12 min) were most beneficial in improving performance measures. This is consistent with animal studies where no difference was observed in the recovery of muscle active properties between 15 or 30 min of massage. Moreover, post-exercise massage may be more beneficial in acute short-term recovery (5–10 min post-massage) compared to longer recovery periods (>1–6 hour post-massage).This hypothesis is consistent with animal studies showing that the sustained effects of massage on tissue stiffness reduction over multiple days were not as great compared to the immediate (pre-massage to post-massage) effects.
Although there appears to be increasing evidence that molecular changes occur within skeletal muscle following massage, the effects of these changes on clinical markers of performance are less clear. The effects of multiple bouts of massage, either daily or at regular intervals over the course of an athletic season, still need further investigation. In addition, the training level of the athlete may also play a role in determining the effectiveness of post-exercise massage as a recovery modality.
This update was published in the Massage & Myotherapy Journal, March Issue.