If you've ever had muscle spasms or muscle cramps, you know they
can be extremely painful. In some cases, a muscle may spasm so forcefully that
it results in a bruise on the skin. Most muscle spasms and cramps are involuntary
contractions of a muscle. A serious muscle spasm doesn't release on its own and
requires manual stretching to help relax and lengthen the shortened muscle. Spasms and cramps can be mild or extremely
painful. While they can happen to any skeletal muscle, they are most common
in the legs and feet and muscles that cross two joints (the calf muscle, for
example). Cramps can involve part of a muscle or all the muscles in a group. The
most commonly affected muscle groups are:
- Back of lower leg / calf (gastrocnemius).
- Back of thigh (hamstrings).
- Front of thigh (quadriceps).
- Feet, hands, arms, abdomen
Muscle cramps range
in intensity from a slight twitch or tic to severe pain. A cramped muscle can
feel rock-hard and last a few seconds to several minutes or longer. It is not
uncommon for cramps to ease up and then return several times before they go
away entirely.
What Causes Muscle Cramps
The exact cause of muscle cramps is still unknown, but the theories
most commonly cited include:
- Altered neuromuscular control
- Dehydration
- Electrolyte depletion
- Poor conditioning
- Muscle fatigue
- Doing a new activity
Other factors that
have been associated with muscle cramps include exercising in extreme heat. The
belief is that muscle cramps are more common during exercise in the heat
because sweat contains fluids as well as electrolyte (salt, potassium,
magnesium and calcium). When these nutrients fall to certain levels, the
incidence of muscle spasms increases. Because athletes are more likely to get
cramps in the preseason, near the end of (or the night after) intense or
prolonged exercise, some feel that a lack of conditioning results in cramps.
Research Supports Altered Neuromuscular Control as the Cause of Cramps
While all
these theories are being studied, researchers are finding more evidence that
the "altered neuromuscular control" hypothesis is the principal
pathophysiological mechanism the leads to exercise-associated muscle cramping
(EAMC). Altered neuromuscular control is often related to muscle fatigue and
results in a disruption of muscle coordination and control.
According to a
review of the literature conducted by Martin Schwellnus from the University of Cape Town , the evidence supporting both
the "electrolyte depletion" and "dehydration" hypotheses as
the cause of muscle cramps is not convincing. He reviewed the available
literature supporting these theories and found mostly anecdotal clinical
observations and one small case-control study with only 10 subjects. He also
found another four clinical prospective cohort studies that clearly did not
support the "electrolyte depletion" and "dehydration"
hypotheses as the cause of muscle cramps. In his review, Schwellnus concludes
that the "electrolyte depletion" and "dehydration"
hypotheses do not offer plausible pathophysiological mechanisms with supporting
scientific evidence that could adequately explain the clinical presentation and
management of exercise-associated muscle cramping.
He goes on to
write:
"Scientific evidence for the "altered
neuromuscular control" hypothesis is based on evidence from research
studies in human models of muscle cramping, epidemiological studies in cramping
athletes, and animal experimental data. Whilst it is clear that further
evidence to support the "altered neuromuscular control" hypothesis is
also required, research data are accumulating that support this as the
principal pathophysiological mechanism for the aetiology of exercise-associated
muscle cramping (EAMC)."
Treating Muscle Cramps
Cramps
usually go away on their own without treatment, but these tips appears to help
speed the healing process:
- Stop the activity that caused the cramp.
- Gently stretch and massage the cramping muscle.
- Hold the joint in a stretched position until the cramp stops.
Preventing Muscle Cramps
Until we learn
the exact cause of muscle cramps, it will be difficult to say with any
confidence how to prevent them. However, these tips are most recommended by
experts and athletes alike:
- Improve fitness and avoid muscle fatigue
- Stretch regularly after exercise
- Warm up before exercise
- Stretch the calf muscle: In a standing lunge with both feet pointed forward, straighten the rear leg.
- Stretch the hamstring muscle: Sit with one leg folded in and the other straight out, foot upright and toes and ankle relaxed. Lean forward slightly, touch foot of straightened leg. (Repeat with opposite leg.)
- Stretch the quadriceps muscle:
While standing, hold top of foot with opposite hand and gently pull heel
toward buttocks. (Repeat with opposite leg.)
Most muscle
cramps are not serious. If your muscle cramps are severe, frequent, constant or
of concern, see your doctor.
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