MUSCLE CRAMPS
Almost everyone who has participated in regular exercise has suffered from a muscular cramp
at some point(1). Particularly in physically active individuals (such as yourselves!), muscle
cramps are common and can be temporarily disabling(6). According to research(9), muscle
cramps have affected 67% of triathletes at some point during training or racing. In addition, 18%
to 70% of marathon runners and endurance cyclists suffer from muscular cramps (5,6,10). The most
common site of muscle cramping occurs in the legs, especially the calf, hamstrings and
quadriceps(1); however it can occur in any muscle group within the body.
WHAT IS A CRAMP?
A muscle cramp is an involuntary and forcibly contracted muscle that does not relax (6,8). Muscle
cramps can range from slight twinges to an excruciating pain and can last from a few seconds
up to several minutes. It is therefore of great importance to prevent the onset of muscle
cramps(4).
WHAT CAUSES CRAMP?
Although there are many athletes and individuals who suffer regularly from muscle cramp, the
pathogenesis of what causes muscle cramp largely remains speculative(2). It is widely believed
that muscle cramp occurs as a result of either:
1. Dehydration
2. Fatigue
3. Fluid and Electrolyte imbalances
However, following the study of 82 male marathon athletes of a similar standard in terms of
racing performance and training, researchers(5) concluded that exercise induced muscle cramps
may not be associated with disturbances of fluid and electrolyte balance. Although 15 (18%) of
the runners reported an attack of muscle cramp, the electrolyte concentrations in the blood were
no different between those who suffering from muscle cramp and those who were not so
affected either before or after the race. These results(5) are also supported by more recent
research conducted in 2005(4). This research concluded that although consuming a
carbohydrate-electrolyte beverage before and during exercise in a hot environment may delay
the onset of muscle cramps, it would appear that dehydration and losses of electrolytes are not
the sole causes of cramping. It was found in the study that 69% of the subjects who suffered
from muscle cramps, were well hydrated and supplemented with electrolytes.
Although the previous research outlined above indicates that we are no closer to discovering
what causes muscular cramping, further studies have concluded differently. One example is a
case study(3) using a tennis player who repeatedly suffered from muscle cramps in warm to hot
weather. It was found that the player extensively and repeatedly sweated during matches
resulting in a consequent sodium (salt) deficit. By ensuring the player was appropriately and
sufficiently ingesting fluid and sodium, enhanced rehydration and fluid distribution occurred in
the player. This lead the researcher(3) to conclude that muscle cramping can be averted. Yet this
was a case study using one subject, realistically, everyone is individual and this may not work
for the next person in line.
Perhaps the best conclusion is that the exact cause of muscular cramping remains a mystery! It
is quite clear that the three likely causes mentioned previously all play a part in the occurrence
of muscle cramps, however a sound, reliable conclusion of why muscle cramps occurs cannot
be drawn from the available research. However, there may be ways of delaying the onset of
muscular cramping and possibly eradicating it.
HOW CAN I AVOID CRAMP?
There are four steps which you can take to help avoid the possibility of muscular cramping
occurring(1,7):
1.
2.
3.
4.
Be well conditioned for the activity you are embarking on.
Regularly stretch, especially the muscle groups which you find are prone to cramping.
Allow for adequate recovery and rest following hard training sessions.
Maintain hydration levels during exercise by drinking the appropriate amounts of fluid.
Sports drinks (such as Gatorade) are recommended(1) as they contain the key electrolytes
that are lost through sweating.
HOW DO YOU TREAT CRAMP? (1)
As mentioned previously, research into the area of muscular cramping is inconclusive and at
some point, even if you are well hydrated, stretched out and feeling good, you may suffer from
muscle cramps. If you do occur from a bout of cramping, light stretching of the muscle affected
will help to decrease the muscle contraction and it will allow the muscle to relax. You may find
that massaging the affected area may also help to alleviate the pain. If the muscular cramping is
extremely severe and/or recurring, applying ice can stop the spasm and help to relieve the pain.
Ensure that you rest and replace lost fluids as this can bring improvement.
DOES CRAMP INDICATE A MORE SERIOUS PROBLEM? (1)
As covered initially, muscle cramps are generally a temporary occurrence and do not lead to
serious problems. However, should see a qualified physician if the muscular cramps you suffer
from:
 Are severe
 Occur regularly
 Fail to improve with simple treatment
 Are not related to obvious causes such as strenuous exercise.
PRIMARY REFERENCES:
1. Australian Institute of Sport (Department of Sports Nutrition) (2004) Cramps and Stitch.
Retrieved from: http://www.ais.org.au/nutrition/HotTopics.asp. Last retrieved: 03/08/05
2. Bentley, S. (1996) Exercise-induced muscle cramp. Proposed mechanisms and
management.
3. Bergeron, M. F. (2003) Heat Cramps: fluid and electrolyte challenges during tennis in the
heat. Journal of Science and Medicine in Sport. 6(1): 19-27.
4. Jung, A. P., Bishop, P. A., Al-Nawwas, A. and Dale, R. B. (2005) Influence of Hydration and
Electrolyte Supplementation on Incidence and Time to Onset of Exercise-Associated Muscle
Cramps. Journal of Athletic Training. 40(2): 71-75.
5. Maughan, R. J. (1986) Exercise-induced muscle cramp: a prospective biochemical study in
marathon runners. Journal of Sports Science. 4(1): 31-34.
6. Miles, M. P. and Clarkson, P. M. (1994) Exercise induced muscle pain, soreness and
cramps. Journal of Sports Medicine and Physical Fitness. 34(3): 203-216.
7. Schwellnus, M. P (1999) Skeletal Muscle Cramps During Exercise. The Physician and
Sports Medicine. 27(12): 109-117.
8. Quinn, E. (2005) Muscle Cramps. Retrieved from:
http://sportsmedicine.about.com/cs/leg_injuries/a/leg8.htm. Last retrieved: 26/07/05.
SECONDARY REFERENCES
9. Kantorowski, P. G., Hiller, W. D. B., Garrett, W. E., Douglas, P. S., Smith, R. and O’Toole, M.
(1990) Cramping studies in 2600 endurance athletes. Medicine and Science in Sport and
Exercise. 22(2 Suppl.): S104.
10. Manjra, S., Schwellnus, M. P. and Noakes, T. D. (1996) Risk factors for exercise associated
muscle cramping (EAMC) in marathoners. Medicine and Science in Sport and Exercise. 28(5
Suppl.): S167.