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Interesting article about muscle cramps. Paging LTH! (Read 119 times)


Bad Ass

    Somebody posted this link to a study/article about muscle cramps.  They discuss the issue of muscle cramps during exercise.  Enjoy.

     

    Link

    Damaris, Marathon Maniac, Ultra Runner

    Next:  San Francisco Marathon

    Blog

    "The most powerful weapon on earth is the human soul on fire."


    Muddling through

      The findings don't surprise me at all.

      2014 Goals: Run first trail ultra, first 100K, and see what I can do in a 24-Hour race


      Bad Ass

        Me either but there are still some (even here) advocating for cramps = dehydration during marathons.

         

        The findings don't surprise me at all.

        Damaris, Marathon Maniac, Ultra Runner

        Next:  San Francisco Marathon

        Blog

        "The most powerful weapon on earth is the human soul on fire."

        Gustav1


        Fear is a Liar

          Interesting article. I noted that it mentioned the synergistic muscle interaction of the foot and calf muscles. Makes me wonder if some of this study could overlap into the causes of achilles  tendonitis or plantar fasciitis. Also shortening of the foot muscle (hallucis) can occur if you try to "grip" the ground with your toes as you run - this will also fatigue the muscle.

           

          I think as far as running goes, we have a few variables - muscle fatigue, dehydration, and mineral imbalance. The nerve signals fire the muscle contractions under normal situations. Maybe a cramp is a nerve "misfire" from a deviation in the above variables.

           

          I just wonder how much they paid the subjects of these studies to be shocked into painful cramps. I think of Wesley in the movie Princess Bride from the scene where he was on the torture device - yowza. I'll pass on that.

          I'm so vegetarian I don't even eat animal crackers!

            Interesting article. I noted that it mentioned the synergistic muscle interaction of the foot and calf muscles. Makes me wonder if some of this study could overlap into the causes of achilles  tendonitis or plantar fasciitis. Also shortening of the foot muscle (hallucis) can occur if you try to "grip" the ground with your toes as you run - this will also fatigue the muscle.

             

            I think as far as running goes, we have a few variables - muscle fatigue, dehydration, and mineral imbalance. The nerve signals fire the muscle contractions under normal situations. Maybe a cramp is a nerve "misfire" from a deviation in the above variables.

             

            I just wonder how much they paid the subjects of these studies to be shocked into painful cramps. I think of Wesley in the movie Princess Bride from the scene where he was on the torture device - yowza. I'll pass on that.

             

            No and no.  Those two things are completely unrelated to cramping.  Several studies have looked at folks that cramp and folks that don't cramp in marathons and there is zero correlation between cramping and dehydration or electrolyte imbalance.  Besides, if those were factors, then cramping could occur in any muscle but it only occurs in the exercising muscles.

            Short term goal: 17:59 5K

            Mid term goal:  2:54:59 marathon

            Long term goal: To say I've been a runner half my life.  (I started running at age 45).


            Bad Ass

              And this article and study agrees with you.

               

               

              No and no.  Those two things are completely unrelated to cramping.  Several studies have looked at folks that cramp and folks that don't cramp in marathons and there is zero correlation between cramping and dehydration or electrolyte imbalance.  Besides, if those were factors, then cramping could occur in any muscle but it only occurs in the exercising muscles.

              Damaris, Marathon Maniac, Ultra Runner

              Next:  San Francisco Marathon

              Blog

              "The most powerful weapon on earth is the human soul on fire."

                I experienced some fairly bad cramping in my first ultra.  I attributed that to a lack of electrolytes for a long time.  The literature convinced me that I was wrong.  I now think it was simply a matter of me being inadequately prepared for the distance.

                Short term goal: 17:59 5K

                Mid term goal:  2:54:59 marathon

                Long term goal: To say I've been a runner half my life.  (I started running at age 45).

                skygazer


                   

                  No and no.  Those two things are completely unrelated to cramping.  Several studies have looked at folks that cramp and folks that don't cramp in marathons and there is zero correlation between cramping and dehydration or electrolyte imbalance.  Besides, if those were factors, then cramping could occur in any muscle but it only occurs in the exercising muscles.

                   

                  Although neuromuscular fatigue is very likely the primary cause of Exercise-Associated Muscle Cramps(EAMC), I don't know how you can completely dismiss other causes.

                   

                  I read the paper through and through, 2x. Let me repeat the 1st sentence of the abstract:"Cramps are sudden, involuntary, painful muscle contractions. Their pathophysiology remains poorly understood."

                   

                   

                  "...Overall, the dehydration–electrolyte imbalance theory has limitations: First, inferences of cause and effect cannot be made from observational data (eg, field studies); causation may be inferred only from meta-analyses and randomized, experimental research designs (evidence levels 1 and 2, respectively).45 Second, although EAMC may appear in the presence of significant electrolyte and/or fluid losses during exercise, numerous other variables associated with exercise may be factors (eg, accumulation of metabolites, intensity of exercise, and acclimatization). Because athletes who experience EAMC often have significant fluid deficits,54 restoring body fluids is an appropriate precautionary measure against the development of more serious forms of heat illness (eg, exertional hyponatremia, heat stroke)."

                   

                  "...The neuromuscular theory also has limitations. The report of altered muscle spindle and GTO activity relies on difficult methodologies that have produced inconsistent results. The majority of GTO Ib afferents (5 of 8, 63%) have only a slight decline or no change in firing in response to stretching of a fatigued muscle.26 Neuromuscular fatigue often induces muscle afferent fatigue with supramaximal electrical stimulation (eg, 100 Hz).28,42 Normal human muscle recruitment patterns indicate stimulation frequencies much lower (eg, < 30 Hz) than those used to induce fatigue in animal studies (eg, 100 Hz).48 Low electrical stimulation frequencies closer to normal recruitment patterns (eg, 16 to 32 Hz) have successfully induced cramps in humans.39,53,55 Thus, the frequencies used to support the neuromuscular theory28,42 do not match normal neuromuscular signaling in humans. Finally, it is unclear how fatigued a muscle needs to become for an EAMC to occur or whether the neuromuscular fatigue is occurring peripherally (ie, in the muscle) and/or centrally (in the spinal cord or brain). Moreover, it is unlikely that neuromuscular fatigue induced with electrical stimulation is the same as fatigue induced with volitional muscle contractions, given that larger diameter motor neurons/units are stimulated first with electrical stimulation and last with volitional contractions.10,24 Muscle fatigue is a continuum rather than an absolute condition. It is likely that the degree of fatigue required to elicit cramping is unique to each athlete."

                  (Note that Neuromuscular theory is supported by level 2 and 3 (no direct level 1) research evidences vs dehydration/electrolites by level 3, and 4)

                   

                  Furthermore, in a lab study also cited in this paper (Jung et al. 2005), while "Nine participants experienced cramps in the carbohydrate-electrolyte trial, compared with 7 in the hypohydration trial. Of the 7 individuals who had EAMCs in both trials, exercise duration before onset was more than doubled in the carbohydrate-electrolyte trial (36.8 ± 17.3 minutes) compared with the hypohydration trial (14.6 ± 5.0 minutes, P < .01)." (Note that all the trial subjects have cramp history that they're more suspect to cramping than people who never experienced cramping before) [Edit: although there's this possibility that the carb, not eletc. intake lessens muscle fatigue that delayed the onset of their cramping]

                   

                  I think in the case of cramping in a race/run, do stretch. If it doesn't help or if the cramping keeps coming back, then check you hydration and electrolytes (though unless you have IV, your body can't make use of what you drink right away).

                  skygazer


                    Forgot to add this (from Miller et al.):

                    "Because EAMC occur in a variety of situations, environmental conditions, and populations, it is unlikely that a single factor (eg, dehydration, electrolyte imbalance, or neuromuscular factors) is responsible for causing them directly. It is more likely that EAMC are due to a combination of factors that simultaneously occur under specific physiological circumstances in each athlete."

                     

                    EDIT: Also in Miller et al., it was mentioned treatment for neuromuscular fatigue(stretching, massage) is often ineffective in treating heat cramp (but Dr. Noake doesn't seem to agree there's such thing as heat cramp as he said cramps happened as often in the cold months as in the warm months (while it's been observed it happens way more often in warm months by other researchers).