Muscle Cramps – What does the science say?
In
exercise the consensus is that there’s two types of cramps – whole body cramps
(fairly uncommon but extremely distressing to the athlete), and cramping of
individual muscle groups (eg. just calves or quads). When cyclists talk about
cramping, generally what they’re referring to is cramping of individual muscle
groups during or immediately after exercise, known as Exercise Associated
Muscle Cramps (EAMC).
Cramps
are generally thought of as short, painful muscle contractions.
EAMC
are thought to occur because the nervous system’s control of muscle contraction
and relaxation is somehow lost. Most people will know from experience that
stretching a cramped muscle will relax it and relieve the pain – that’s because
it activates parts of the muscle fiber that regulate relaxation. There’s a
variety of nutrition supplements and remedies marketed as preventing or
treating EAMC by preventing changes in the nervous system’s control of muscle
contraction and relaxation. But do they actually work?
Only
one study identified that a sports drink delayed the time until calf cramping
commenced in comparison to not drinking anything.
Does
loss of body weight or Total Body Water influence risk of cramping? There’s not
a lot of research in this area, but what does exist suggests that it doesn’t.
As one recent review of the science described: “A careful review of the
literature did not identify a single published scientific study showing that
athletes with acute EAMC are more dehydrated than control athletes
Since 1986 four controlled studies have been
published, all showing no relationship between any electrolyte levels and the
risk of cramping during exercise. In these studies there was no difference in
electrolyte levels at the time of cramping compared to other times (or the
athletes who didn’t cramp at all). And when cramping resolved there was no
change in electrolyte levels that could explain an effect of rehydration or
supplementation to relieve the cramping. This is probably not a surprise
considering that EAMC’s are localized – they occur in a specific muscle group
or groups. How would an electrolyte imbalance throughout the whole body cause
cramping in only one muscle group?
Distinct risk factors for developing EAMC have emerged:
§
Aggressive pacing
strategies (trying to go faster than your current personal best over a set
distance).
§
Racing at a higher
intensity then what you normally ride in training
§
Riding for longer
than you‘re used to
§
Doing another type
of exercise you’re not used to (eg. a cyclist running a one-off marathon)
Given that most people only cramp during the latter stages of a
race, on an epic ride, a monstrous hill climb or after spending time off the
bike, these factors are probably not a huge surprise to you. It’s also
interesting to note that the volume or intensity of training does not predict
cramping risk. The difference appears to be that the athletes who are
over-ambitious and try to punch above their weight on any given day increase
their risk of cramping.
It’s
thought that some form of muscle fatigue occurs which leads to the onset of
EAMC. This appears particularly true when a muscle group is working in a
shortened position (eg. calves when pointing your toes in swimming, quads when
you get out of the saddle and fully extend the legs of a bike). This suggests
that poor biomechanics may increase muscle fatigue and lead to greater risk of
cramping.
Helpful strategies to minimize your risk of
EAMC :
- A good bike setup
is not a bad idea if you’re a frequent cramper.
- Make sure you get
at least some training sessions in at the intensity that you race at, some
long rides (equal or longer than races).
- Maximizing
carbohydrate consumption during a race may also help reduce cramping risk
by maximizing the number of fibers being activated in a muscle group and
minimizing fatigue.
- Being checked for
proper spine alignment. The spine
house the nervous system and when misaligned will effect the neurologic
input to the muscles resulting in decrease power, endurance, and cramping. Getting a chiropractic adjustment may
ameliorate EAMC.
918.249.1535
Chiropractic
sports physician
Chiropractor
in Broken Arrow
