Weschler is a Contributing Editor to UltraCycling, a physical therapist and ultra cyclist.
A muscle cramp is a muscle contracting when you didn't tell it to, and staying contracted to an exquisitely painful extent when you are begging it to stop. Cramping has happened to many a rider and wrecked more than a few performances.
Many of us have learned from experience that:
The theory has a neuro-physiological basis that takes a little explaining. Put your mind in the big chainring and hang tough: when you understand this, you will be a smarter stretcher as well.
All muscles have two elegant sensing systems physically built into them. The first of these is based on the muscle spindle. Many spindles are found in every muscle belly, running parallel to the muscle fibers. The spindle senses, and things are wired so that the muscle responds to, length, changes in length and the rate of change of length in the muscle. When a muscle is quickly stretched, the spindle tells the muscle to contract, and to do so right now! (Different nerve cells conduct signals at different rates, and these are the fastest conductors in the body.) The spindle itself can, like muscle fibers, contract. If the muscle stays shortened, the spindle will eventually detect this state and will itself shorten. In other words, it re-sets itself so that it will be ready to tell the now shorter muscle to contract when once again it is quickly stretched.
Now take that shortened muscle and make it tired as well. Animal studies (Nelson and Hutton, 1985) show that muscle fatigue makes the spindle more "excitable", meaning you need less of a stimulus to set it off (ref: Schwellnus et al also cite increased EMG activity in recently cramped muscles as evidence of increased spindle activity).
Spindle operation is why you want to stretch slowly (and never bounce!). A quick stretch makes a muscle contract, or shorten, the exact opposite of what you are trying to do by stretching.
The Golgi Tendon Organ (GTO) is the functional unit of the second sensing system. GTO's are built into every muscle-tendon junction (tendons are at the ends of muscles, attaching them to bones). The GTO responds to tension (or amount of pull), change in tension, and the rate of change in tension of muscle. Its response is inhibitory: increase the amount of tension in a muscle, and the GTO sends signals to decrease its contraction. The GTO prevents a muscle from tearing by not allowing it to develop too much tension.
Unlike the spindle, the GTO cannot itself contract. When you've shortened up a muscle, the GTO does not shorten. It just sits there like an un-stretched rubber band. Its ability to sense tension is compromised, and it is less able to "stop a cramp before it happens." As with the spindle, it may be even worse: the new hypothesis cites animal studies (Hutton and Nelson, 1986) which show that in a fatigued muscle, the GTO is itself inhibited, and hence firing its signals at a slower rate.
Here is how to use your GTO's to enhance your stretching. Stretch a muscle, for the sake example your hams, as far as they want to go (before pain, of course!). Then, contract isometrically to increase tension in the muscle. To do this for your ham, press your heel or whole leg onto whatever surface you are sitting on. Press hard, without moving, and after 5-10 seconds, gently but completely let go of the contraction, again without moving. Slowly resume your stretch, and see if you go a little further! You may already have heard this referred to as "a PNF method" or as "contract-relax" or "hold-relax.'
To summarize current cramping theory: Fatigue makes the muscle spindles more excitable, making the muscle poised to contract. It also results in an inhibited GTO, thus blocking a defense against too strong a contraction. Breaking a cramp is a matter of stretching the muscle, which both gets the GTO to send its inhibitory signal, and quiets down the muscle spindle. Stretching the muscle stretches the spindle, and the longer the spindle, the less "edgy" it becomes. Then, to flush a cramp, work it in an elongated position to take advantage of the GTO's inhibiting signal.
My experience says muscles don't have to be tired to cramp. Get a muscle short, and contract it (that is, make it work) in that short position. This recipe works especially well with two-joint muscles, examples of which are the Gastrocnemius, Hamstrings and Rectus Femoris (see below). You can get a two-joint muscle relatively shorter than a one-joint muscle. After you shorten the muscle over one joint, you can flex another joint to get it even shorter! The fact that two-joint muscles are more predominantly fast-twitch muscles has something to do with their readiness to cramp.
If the acrobatics on the bike prove too much, then get off the bike, take the muscle to its full-stretch position and resist its isometric (or very short range concentric) contraction there. When you get back on the bike, work the muscle in the range (or arc) suggested below. Gradually increase that arc. You'll know the cramp is completely gone when you can get the muscle to work exactly as you'd like through the whole pedal-stroke.
The Gastrocnemius (a two-joint muscle) is the fleshy calf muscle which, when you're standing, raises you up on your toes (or in general, points your foot down, away from your nose). The second joint it crosses is the knee, which it bends. So to make it cramp, bend your knee and point your toes down. To un-cramp it on the bike, put the crank in 5-6 o'clock position, slide back in the saddle, lock your knee straight and slowly drop your heel as far as you can get it to go. To flush the cramp, stay back in the saddle, keep your toes pointing towards your nose, and make the muscle work in the 4-6 o'clock part of your pedal stroke. Let it go "along for the ride" through the rest of the pedal stroke where it is shorter and once again, ready to cramp.
The Hamstrings (two-joint muscles) are the fleshy muscles at the back of the thigh. You can find their tendons: stay seated and put both hands on your right thigh, near the knee, so that your left hand is on the inside of the thigh and your right hand is on the outside. With your thumbs on top of the thigh, use your index and middle fingers to find the cord-like tendons just under the thigh near the knee. (Careful feeling will reveal two, not one, tendons on the inside.) Follow them to where they attach to the leg (if pressing where the inside ones attach to bone evokes tenderness, then you need to stretch both hams and adductors).
These muscles bend the knee and straighten the hip. Here is how to start a cramp that might put you in orbit: lie on your stomach, straight at the hip and with your knee bent so that your heel comes close to the butt. Pull the heel closer to the butt. Better yet, have someone try to pull your heel away from the butt while you resist them! See you on the moon!
To un-cramp on the bike, put the crank at 4-5 o'clock position, slide back in the saddle, bend forward at the hip, and lock your knee straight (don't point your toes down, but don't pull them up either). To flush, try a few pedal strokes like this: slide back in the saddle, bend forward at the hip, and pull down on the pedal stroke in the 3-4 o'clock range. This may not give you quite enough resistance; if this is the case, then coast, and try to pedal while you hold the crank stationary in the 3 o'clock position with your other leg.
The Rectus Femoris is the only one of the four quadriceps (muscles in front of the thigh) that is a two-joint muscle. It crosses the knee joint, and like the other quads, straightens the knee. It also crosses the hip and flexes, or bends the hip. Here is how to cramp it: sit with your leg straight out in front, and try to lift your leg (this method may not work if you have tight hamstrings!).
Un-cramping can be tricky because the RF's stretch position is the hams' cramp position and if you've already cramped one muscle, others are ready to go. The key to keeping the hams happy and un-cramped is to let them go along for the ride; do not contract them as you try to break the RF cramp. Un-clip, reach down and grasp your ankle or the heel of your shoe. Keep straight at the hip and use your hand to pull your heel to your butt. If you sense a ham cramp coming, then you'd best get off the bike. Lie on your un-cramped side, reach with your hand for your ankle or shoe and proceed as above. Or lie on your stomach, and have your crew gently bend your knee, pushing your heel to your butt. Let your crew do it. Do not help to pull the heel to your butt with your hamstring, or you and your crew will wind up on the moon! When the cramp is broken, your crew can hold your leg in that position while you try to straighten the knee, and even allow you a small arc of motion to flush the cramp.
To flush the cramp while riding, sit up as straight as you can and make the cramping leg work the 12-1:30 o'clock arc. This is less effective than the off-the-bike method, but you may be able to get it to work.
The other three quads are one joint muscles; they straighten the knee. Since these muscles don't cross the hip, you can allow the hip to bend when you're trying to break their cramps, without the possibility of cramping the hams. Usually, the cramp will be near the knee on the inside of the thigh (Vastus Medialis muscle). To break a cramp at the inside of the thigh, un-clip and pull your ankle so that your heel touches your butt. You will be using your right hand for your right ankle, and it augments the stretch a little if you bring your heel up to a little outside of the thigh. If the cramp is on the outside of the thigh (Vastus Lateralis muscle), then stretch so that your heel comes up a little inside of the thigh.
To flush quad cramps, work with your knee bent at as acute an angle as you can. Make it work only at the top of the pedal stroke, say 12-1:30 o'clock, and let it go "along for the ride" through the rest of the pedal stroke until it flushes.
The Intrinsic Foot Muscles are tiny little muscles that lie between the long bones of the foot, and it is amazing how much misery they can cause. In their shortened position, the toes point down, away from the nose and sideways. To break the cramp, grasp your toes in the palm of your hand and bend them (and perhaps your whole foot) towards your nose as far as your carbon-soled shoe will allow. Be persistent, but if this doesn't work, you've got to stop, sit on the side of the road, take the shoe off, and bend the toes up. Ah, relief! When you get back on the bike, keep your toes pointed up as much as your shoe will allow. This is the best I can say as to how to flush these little devils.
The little finger side of the hand has a small muscle with a big name (Abductor Digiti Quinti Minimi). Its cramping is perceived more as an aching pain. If it hurts there, try treating it as a cramp. The muscle is short when the little finger is bent towards the palm and points away from the others. To break a cramp in your right hand, straighten your right hand and fingers, and use your left hand to bend it back at the wrist and in the direction of the thumb side of your hand. Use the contract-relax technique to flush the cramp: Hold the right hand still in that fully stretched position and make it work against the resistance of your left hand. The comments on the foot intrinsic muscles apply here as well.
You don't need to be brushed up on anatomy to know what to do for any other muscles. Bend as many joints as you can away from the cramp. If, for example, you cramp on the palm side of your forearm, then bend your hand backwards, and straighten your elbow. Then, just keep the muscle as close to that stretched position as possible, and coax it to work a little.
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Experience Also Tells Us:
Guyton, Arthur C. and John E. Hall. Medical Physiology, 10th Edition. Philadelphia, W. B. Saunders
Bentley, S. Exercise-Induced Muscle Cramp. Proposed Mechanisms and Management. Sports Med 1996 Jun;21(6):409-420.
Schwellnus, MP, Derman EW; Noakes TD. Aetiology of Skeletal Muscle "Cramps" During Exercise: A Novel Hypothesis. J Sports Sci 1997 Jun;15(3):277-85.
Schwellnus, Martin P. Skeletal Muscle Cramps During Exercise. Phys Sports Med 1999. (http://www.physsportsmed.com/issues/1999/11_99/schwellnus.htm)