Cramps, causes and prevention

[danvolker]

I've never taught Scuba. I've been asked a few times but I didn't want to turn something I did for pleasure into work. I just retired from teach first aid up to from basic through Occupational, O2 and Analgesic Gasses.

The move towards teaching more mid-water and away from kneeling seems like a move in the right direction. I certainly couldn't kneel without cramping up for sure. You method does at least provide for the stretching of the muscles

Frustrating tho sometimes the cramps start early on in the dive no matter what I do. It does seem more likely towards the end of the dive at the 80 minute mark or thereafter. I don't think I would ever be able to solve the problem well enough to get into the long technical

Time for guess-timating

If you look at a scuba dive that goes on for 80 minutes.....there are a few things going on that relate to a long run or bike ride...and how those activities can create cramping due to physical exertion.

• At some point on a run or bike ride, your muscles will run out of stored glycogen( note there is both a reserve for aerobic and anaerobic energy). After you exhaust aerobic glycogen, and you are using up your anaerobic glycogen, you begin to feel lactic acid buildup quickly, and cramping begins soon afterwards, as a result of ph changes from anaerobic glycolysis :

Anaerobic glycolysis is the transformation of glucose to pyruvate when limited amounts of oxygen (O₂) are available. Anaerobic glycolysis is only an effective means of energy production during short, intense exercise, providing energy for a period ranging from 10 seconds to 2 minutes. The anaerobic glycolysis (lactic acid) system is dominant from about 10–30 seconds during a maximal effort. It replenishes very quickly over this period and produces 2 ATP molecules per glucose molecule, or about 5% of glucose's energy potential (38 ATP molecules). The speed at which ATP is produced is about 100 times that of oxidative phosphorylation. The pH in the cytoplasm quickly drops when hydrogen ions accumulate in the muscle, eventually inhibiting enzymes involved in glycolysis.​

The burning sensation in muscles during hard exercise can be attributed to the production of hydrogen ions during a shift to anaerobic glycolysis as oxygen is converted to carbon dioxide by aerobic respiration faster than the body can replenish it. These hydrogen ions form a part of lactic acid along with lactate. The body falls back on this less efficient but faster method of producing ATP under low oxygen conditions. This is thought to have been the primary means of energy production in earlier organisms before oxygen was at high concentration in the atmosphere and thus would represent a more ancient form of energy production in cells.
The liver later gets rid of this excess lactate by transforming it back into an important glycolytic intermediate called pyruvate; see Cori cycle.

• Divers that use up their stored energy ( in leg muscles and liver) will be forced to fin swim via anaerobic glycolysis....and cramping is always just around the corner with this....the solution to this is 3 day or more per week long duration workouts of the primary muscles used in fin swimming, to force them to store more aerobic glycogen....Think about the average person that cramps up after riding a bike 8 miles....and think of a Tour de France rider, doing 120 miles per day, for over 20 days in a month.....You absolutely CAN change the amount of stored energy you can store in your fin swimming muscles.
• Divers that skip breath, or that reduce heart rate and ventilation( breathing) to a minimum, can put their fin swimming muscles into a state of insufficient Oxygen for aerobic respiration to supply sufficient power to their fin swimming muscles, and this can be very much like a cyclist that can ride well at 15 mph for 2 hours, that trys to ride at 19 mph for 2 hours.....when they get over the point at which they are supplying sufficient O2 to the muscles, they cause Anaerobic glycolysis to begin....Skip breathing or forcing a low heart rate when muscle contractions are calling for more power, does the same to the diver as the 19mph ride does to the cyclist in this example.
• As divers, we are supposed to slow our heart rate down, maximally, and this slows our breathing rate way down....If you do this well enough, at some point, it is not hard to interfere with your energy supply--that which is powering your fin swimming. Higher VO2 Max individuals will be much less effected by this, than LOW VO2 max individuals.
• VO2 Max can be raised significantly by interval training...but each person has a genetic limit.

 

[bowlofpetunias]

My dives are usually very slow and easy I don't do a lot of fining it is all about relaxing, watching the critters and getting a few pics. I suspect a lot of the problem later in the dive has more to do with the bent knee position I assume to maintain trim and avoid silting.

If I make a point of stretching out and using full leg fin kicks every once in a while it seems to help. Of course the problem with that is I have to move up in the water column to avoid silting or brushing anything. I like to watch the small stuff and that tends to be hiding not mid water

:lol: yeah genetics and age do catch up with us sometimes

 

[danvolker]

My dives are usually very slow and easy I don't do a lot of fining it is all about relaxing, watching the critters and getting a few pics. I suspect a lot of the problem later in the dive has more to do with the bent knee position I assume to maintain trim and avoid silting.

If I make a point of stretching out and using full leg fin kicks every once in a while it seems to help. Of course the problem with that is I have to move up in the water column to avoid silting or brushing anything. I like to watch the small stuff and that tends to be hiding not mid water

:lol: yeah genetics and age do catch up with us sometimes

The only times I have ever experienced cramping, were when I was going very slow, for a very long time.
I am thinking that this is from a phenomenon bike racers refer to as "blood shunting", where your body begins to optimize blood flow over 20 minutes to an hour or so, and dilation of blood vessels may exist at key areas your body deems as essential, and constriction of blood vessels occurs in many of your primary muscles which the body assumes are not essential at the moment.

A good time trialist, can actively shunt blood away from their upper body on the bike...the arms and chest effectively go to sleep( no muscle contractions to speak of, very low bloodflow, very low oxygen being "wasted" in this region)...and the major blood flow goes to the big driving muscles in the quads, glutes, calves...and of course still goes to the brain....

If you or I were to be in perfect trim, and are frog kicking with one kick cycle every 20 seconds or so, heart rate down to 55 beats per minute, breathing maybe 3 times per minute or so....the circulation of blood oxygen is going to get concentrated in the brain, and all peripheral muscles may well have some constriction of blood flow, to facilitate sufficient blood oxygen for the brain, given the extremely low heart rate and breathing rate. My theory in this, is that as with bike racing, a diver is consciously altering blood flow, while also consciously forcing breathing rate and heart rate to be as low as they possibly can.

Constriction of the blood vessels in the legs can be further exaggerated, by the exposure to cold water, which is naturally going to cause constriction in the blood vessels, and this will limit both blood oxygen distribution within the legs, as well as dispersion of aerobic energy( glycogen) to power the muscle contractions--meaning the leg muscles will be forced to be run more on anaerobic glycogen( in the absence of sufficient oxygen, they have to be powered by anaerobic glycolysis). Even at the most gentle of kick contractions, at a few per minute, with a heart rate of absolute resting rate, your muscles will be powered largely by anaerobic respiration, and cramping will be an expected result at some point.

Solution if this is what's going on......Breath a lot more, and keep your legs much more active, to prevent shunting....try to keep your heart rate much higher, and as Dumpster said, keep your legs and feet as warm as possible.
Use a heart rate monitor to see what your HR is typically when you are starting to cramp....there is a whole range of things to try if this tangent seems involved in the cramping...

If we figure this out, it can help everyone!

 

[Lorenzoid]

I am prone to cramps in my calf as well as in the arch of my foot. Although I used to be able to run long distances, in recent years I have become prone to cramps in my calf after running just a few miles. The arch cramp happens during diving (frog and modified flutter), swimming laps, and sometimes in the gym after doing the stairmaster machine. I have tried supplements and stretching, with little success. Maybe I'll add cycling to my routine.

 

[danvolker]

Maybe I'll add cycling to my routine.

If you try it, please try it with orthotics , and with a high seat position with toe pointing down at bottom of pedal stroke. Go for complete range of motion for your calves. dont worry that many cyclists like to pedal with feet flat at bottom of stroke---that will not help diving.....and...plenty of Track sprinter cyclists use toe pointing to gain better leverage ( a longer lever) . This makes them naturals for diving
If your arch and foot are not stabilized by a decent orthotic, when power gets transferred to your foot from your lower leg, the muscles in your foot will fail to keep your foot in the correct "posture" for transferring power....if the arch gets flattened, many muscles in the foot will begin to be overworked rapidly, and cramping will result.

 

[Dhboner]

I had some thoughts on this issue as a marathon runner and amateur student of exercise physiology but Dan Volker's "treatise" blows anything I could add right out of the water (pardon the pun). That explanation is concise, accurate and insightful. Thanks very much Dan.

 

[Lorenzoid]

If you try it, please try it with orthotics , and with a high seat position with toe pointing down at bottom of pedal stroke. Go for complete range of motion for your calves. dont worry that many cyclists like to pedal with feet flat at bottom of stroke---that will not help diving.....and...plenty of Track sprinter cyclists use toe pointing to gain better leverage ( a longer lever) . This makes them naturals for diving
If your arch and foot are not stabilized by a decent orthotic, when power gets transferred to your foot from your lower leg, the muscles in your foot will fail to keep your foot in the correct "posture" for transferring power....if the arch gets flattened, many muscles in the foot will begin to be overworked rapidly, and cramping will result.

I don't do any mountain biking anymore, but I still have the off-road cycling shoes that I guess would work with the pedals on the spinning machines at the gym. Yes? Many thanks for the advice.

 

[danvolker]

I don't do any mountain biking anymore, but I still have the off-road cycling shoes that I guess would work with the pedals on the spinning machines at the gym. Yes? Many thanks for the advice.

Most mountain bike shoes can take many kinds of cleats.....so let the bike shop know what kind of pedals are on the spin bikes, and they should get you the right cleats for it....nice inexpensive solution. When you start doing this, the first several days you do this, think mostly about the kick shape, and what muscles you are trying to work, and the firing order. Start with 75 rpm to 90 rpm at low resistance, dont spin fast till your low speed coordination and firing order is optimizing....I'd probably work on simulating a bigger gear, and pushing harder, before I would get to high cadence....and then there is the diving issue, where your spin bike-low cadence with bigger leverage/bigger gears, is more associated with fin swimming.
Also, a fairly forward seat position, more like a time trial bike position, is likely to get closer to working the diving muscles more optimally--it concentrates more on the quads and hips, less on the glutes ( in cycling glutes can be a large part of pushing the pedal forward and the beginning of down stroke--seat positon futher back accentuates this...and this is not functional for fin swimming, so the more forward saddle position will help to take the gluteal muscles out of the equation, and concentrate more on the quads. You will feel this, and use biofeedback as you think about the kick shape and firing order.)

 

[guyharrisonphoto]

Dan, thanks for your input! I don't cramp on our high-energy dives when we are dealing with current. Rather, I cramp like bowlofpetunias, when I am in bent-leg "perfect" trim after a long stretch on our very slow frog-kicking two hour macro dives, and I get calf cramps. What helps me there is getting off the bottom, stretching out the legs and a couple minutes of good old flutter kicking. I now have some insight into why! My dive computer has a heart rate monitor feature and I am going to start using it and keeping mental notes. I am also going to look at upping my breathing rate--would rather have a two hour comfortable dive than 2.5 hours dealing with cramps the last half hour.

By the way, as for foot cramps, nothing, and I mean nothing, comes close to the freedom from pressure as the force fin design. I think that a cheap cycling shoe (or a bootie with orthotic) combined with the FF would make any foot cramps go away forever.

This is a great thread!

 

[The Chairman]

In the words of Simon and Garfunkle: "Slow down, you Scuba too fast!"

I'm not trying to take a thing away from Dan, but it's my opinion that most divers work too hard. Way too hard. Waaaayyyy too hard. They swim circles around me and wonder why they use ungodly amounts of gas, and don't have any energy after the dive. Slow down! Slow waaaayyyy down. Learn to avoid currents and trying to keep up with that race horse buddy.