Help With Muscle Cramp Physiology - Is This BS?

5magicbeans

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My son frequently deals with muscle cramping when he plays tennis. Have been using salt, sugar (cokes, fruit juice etc.) protein, magnesium etc. Would appreciate any other recommendations. Saw this ad and wondered if this is correct physiology for cramping??

Science
Jul 13, 2016
By: Dr. Bob Murray, Managing Principal at Sports Science Insights and advisor to HOTSHOT

Sheila had been training hard for the past six months in preparation for an Ironman qualifying event. Despite a bout of Achilles tendonitis, a twisted ankle, a week-long case of the flu, and disruptions in her training schedule due to unexpected work travel, Sheila was in great shape and ready to go. On race day, she quickly settled into her swim and was pleased with her time. The bike leg had some challenging hills and she could feel her quads starting to fatigue during the final 30 miles. Sheila started slowly on the run, taking care not to push too soon. By mile 5, she had eased into a pace she hoped to hold for the remainder of the marathon. When she reached the bottom of the first hill at mile 7, she stumbled a bit, but quickly caught her balance. Three strides later, her left hamstring muscles seized into a painful cramp, dropping Sheila to her knees. After a few minutes of stretching, the cramp dissipated and she gingerly walked, then jogged before attempting to regain her run pace. Only a few minutes later, the cramps struck again. After suffering through three more episodes of cramp-stretch-walk-jog-run-cramp, Sheila gave up in great frustration. All that hard training and preparation down the drain because of muscle cramps!

Athletes in all sports can relate to Sheila’s story—and that’s particularly true for athletes who have a history of muscle cramps. Even though Sheila was well hydrated and had consumed plenty of carbohydrate during the race, cramps that she had never experienced during training literally brought her to her knees. Why did she cramp? Why just her left hamstrings? What could she have done to prevent it?

Although it’s likely that muscle cramps have been around since the dawn of man, only recently are scientists beginning to understand what causes a muscle to cramp and how that cause has opened the door for effective interventions to prevent and treat cramps. The cramps that afflict athletes are called “exercise-associated muscle cramps” or EAMCs for short.

What causes a muscle to cramp in the first place? In healthy athletes, muscles don’t cramp on their own. Constant input from the nerve that controls individual muscle fibers (muscle cells) is required to spark and sustain the constant contraction of thousands of muscle fibers. So what causes those nerves to become hyperactive? To answer that question requires a little background in the structure and function of motor nerves—also called alpha motor neurons, the nerves that innervate skeletal muscles.

Motor nerves extend from the spine all the way to the muscle fibers they innervate. In some cases, the motor nerve might be three-feet long. Take a look at the figure and you’ll see that motor nerves have four main parts: the dendritic branches, the cell body, the axon, and the terminal branches. In leg muscles, one motor nerve might attach to and control over 1,000 individual muscle fibers. For example, the gastrocnemius muscle in the calf has 580 motor nerves and each nerve connects to roughly 1,700 muscle fibers. If one motor nerve fires, all 1,700 muscle fibers contract in unison; the more motor nerves that are activated, the stronger the contraction.

Motor nerves are controlled in part by nerves that extend from the brain to the spinal cord so that whenever we voluntarily decide to move, those nerves signal the motor nerves to cause the appropriate muscle contractions. Pretty straightforward. But motor nerves also receive input from thousands of other nerves located in the spinal cord, along with nerves that deliver information from muscles to the spine. In fact, two-thirds of the nerves associated with muscles provide this type of sensory feedback to the spine. Long story short, each motor nerve receives input from tens of thousands of other nerves via its dendritic branches. All that incoming information is sorted by the cell body; and, if the conditions are right, impulses are sent down the axon to the terminal bulbs that connect to individual muscle fibers.

If one or more motor nerves are constantly stimulated, all the connected muscle fibers contract, causing fasciculations (twitches) when just a few motor nerves become hyper-excited or a full-blown cramp when many motor nerves are activated. Motor nerves can become hyper-excited if they are overwhelmed by incoming information from other nerves around the body. In Sheila’s case, the fatigue of the race, the gradually increasing muscle damage, her elevated body temperature, and perhaps even the brief stumble she experienced, all conspired to make many motor nerves serving her left hamstring muscles hyper-excited. Stretching the muscle relieves the cramp by increasing the amount of inhibitory input sent from the cramped muscle to the spine. Sheila used stretching to temporarily stop her cramping, only to have the cramps reoccur whenever she began exercising again.

In summary, exercise-associated muscle cramps are caused by hyperactive motor nerves and are prevented or treated by restoring the nerve’s normal function. For those reasons, athletes should follow sound recommendations for training, pacing, nutrition, and hydration to prevent motor nerves from becoming hyperactive. If cramping still occurs, stretching the affected muscles will stop the cramp, at least temporarily.

Of course, for Sheila and other athletes, preventing cramps is much better than having to treat muscle cramps during training and competition. HOTSHOT® is formulated to keep motor nerves from becoming hyperactive by stimulating sensory nerves in the mouth which send signals to the brain and spinal cord to help maintain normal nerve and muscle activity. This neural connection is now helping athletes avoid the pain and frustration of muscle cramps. It’s also possible that the science of TRP channels might unlock other benefits to Neuro Muscular Performance that could aid training, racing, and recovery, possibilities now under laboratory study.

Motor nerves extend from the spine all the way to the muscle fibers they innervate (see Figure A).

alphamotorneurons-2-1.jpg
 

Diokine

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I would say not entirely accurate. There is a lot of feedback from the muscle itself to the nerves, it's not a one way street. Muscle cramps basically come down to a lack of ATP production or recycling for whatever reason (there are many.) Hypothyroidism and inadequate calcium intake are probably the biggest reasons for cramping like your describing. Vitamin D is also very important.
 

Koveras

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Agree with Diokine above, would add that nutritional strategies to support thyroid function like adequate carbohydrate intake and intake of all the minerals (calcium, sodium, potassium, and magnesium) may help.

You could also always give pickle juice a try:

"pickle juice" cramps - PubMed - NCBI

"Pickle juice, and not deionized water, inhibits electrically induced muscle cramps in hypohydrated humans. This effect could not be explained by rapid restoration of body fluids or electrolytes. We suspect that the rapid inhibition of the electrically induced cramps reflects a neurally mediated reflex that originates in the oropharyngeal region and acts to inhibit the firing of alpha motor neurons of the cramping muscle."
 
OP
5

5magicbeans

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[QUOTE="
"Pickle juice, and not deionized water, inhibits electrically induced muscle cramps in hypohydrated humans. This effect could not be explained by rapid restoration of body fluids or electrolytes. We suspect that the rapid inhibition of the electrically induced cramps reflects a neurally mediated reflex that originates in the oropharyngeal region and acts to inhibit the firing of alpha motor neurons of the cramping muscle."[/QUOTE]

Thanks for replies. This is interesting. It seems to support the advertised products theory to some degree in that it is referring to a "neurally mediated reflex that originates in the oropharyngeal region". Apparently their product has a similar function as pickle juice...refocusing the nerve reflex.
Could one of the causes really be a "nerve reflex"? Vagus nerve?
 

Koveras

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Thanks for replies. This is interesting. It seems to support the advertised products theory to some degree in that it is referring to a "neurally mediated reflex that originates in the oropharyngeal region". Apparently their product has a similar function as pickle juice...refocusing the nerve reflex.
Could one of the causes really be a "nerve reflex"? Vagus nerve?

Certainly possible.

On the TRP channels "It’s also possible that the science of TRP channels might unlock other benefits to Neuro Muscular Performance that could aid training, racing, and recovery, possibilities now under laboratory study."

Pregnenolone sulfate - Wikipedia, the free encyclopedia
"...In addition to its effects on ligand-gated ion channels, pregnenolone sulfate is an agonist of the sigma receptor,[2] as well as an activator of the TRPM1 and TRPM3 channels.[1] It may also interact with potassium channels and voltage-gated sodium channels."

"...TRPM3 is a polymodal ion channel activated by a variety of different stimuli like hypotonicity [100], sphingolipids [101], steroids [6,102], nifedipine [6], and heat [103].

via Pregnenolone For Protection Against Melanoma

Some other interesting research on possible performance benefits of merely rinsing carbohydrates in your mouth, without swallowing.

carbohydrate mouth rinse - PubMed - NCBI

Doesn't look like it would be that hard to make a very cheap tea on your own to test the effect:

"HOTSHOT contains filtered water, organic cane sugar, organic gum arabic, organic lime juice concentrate, pectin, sea salt, natural flavor, organic stevia extract, organic cinnamon, organic ginger and organic capsaicin."
 

Diokine

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I was curious to the proposed mechanism of pickle juice cramp reduction, regarding the neural reflex, so I did a bit more reading on what they were talking about. I hold the nerves in really high regard, vagal tone in particular is incredibly important. I think the brain quite literally has control over the functioning of every cell in your body, and a large shift in the tone of the nerves could definitely effect muscular physiology enough to reduce cramping. I still think that the best approach is to apply nutritional strategies like Koveras said, but exploring the interactions of the different nerve tones would be a great corollary. I'd be interested to try some breath exercises like recovery breathing during cramping, I've used the ideas to great success during workouts. I've found breathing exercises to be one of the most powerful things available to me to alter nerve tone quickly.
 
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I find potassium in the form of inorganic litesalt or nosalt (brand namesake) potassium chloride sometimes with s little magnesium gets rid of cramps instantly. I find NaCl salt is the wrong thing and makes them worse.

If you have enough milk and/or fruit you get loads of potassium. And probably no cramping. So times magnesium lack causes cramps too but usually it's imbalance of too much sodium. At that point the inorganic potassium, just 100 mg or so works brilliantly.
 

Lianda

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I get cramping sometimes with exercise, but the major problem I have is that I have frequent cramps while just sitting around. The WORST cramps actually wake me up in the middle of the night when I can feel cramping in my calves and sometimes entire leg. It's AWFUL!! My doctor tried to convince me I have "restless legs". I don't have ANY of those symptoms.... I have noticed however, that my muscles seem to be getting weaker. Any suggestions?
I take 600-700 mg of magnesium daily (cannot function without it)- calcium (and get that from Tums for heartburn which is frequent), have my Vit.D levels checked, and they're good. I am dx'd with Hashimoto's.
 
EMF Mitigation - Flush Niacin - Big 5 Minerals

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