All you need to know about muscle cramps

What?

Muscle cramp is the sudden and involuntary painful contraction of muscle (or part of it), which disappears within seconds or minutes and is often accompanied by knotting of the muscle during touch.

Cramp is the repetitive firing of motor unit action potentials, also known as “cramp discharge”.

The cause of cramping is unknown, however it is traditionally believed to be associated with exercise in hot and humid climates i.e. Dehydration and the depletion of electrolytes. However this isn’t fully backed by scientific evidence. Another theory suggests there is a neuromuscular cause. This thought proposes that the muscular overload and neuromuscular fatigue causes an imbalance between the excitatory impulses from muscle spindles and inhibitory impulses from Golgi Tendon organs. However, due to muscle cramping occurring within a variety of situations and environments conditions, some believe it is unlikely that there is a single cause.

Cramp vs. Spasm

It is possible to distinguish cramp from spasms. A spasm is an involuntary and abnormal muscle contraction, however cramps are severely painful (and can result in continued soreness), carry an involuntary and explosive onset with a gradual termination of the muscle stretching. This involves only one/one part of the muscle and it is possible to experience fair and forceful contractions. In addition, muscle cramps tend to occur within the muscles of the calf and foot which can in turn impair athletic performance.  

Who?

Cramps can occur in individuals with motor neuron disorders and metabolic disorders, but can also occur within healthy individuals during sleep, pregnancy and physical exertion.

Some of the reported risk factors for exercise-associated cramps include-

• Inadequate conditioning for the activity
• Increased exercise intensity and duration
• Previous history of cramps during or after exercise
• Family history of cramping.

Treatment

• Moderate static stretching 
• Prevention and treatment methods include fluid and electrolyte balance strategies. The National Athletic Trainers’ Association recommends that athletes prone to muscle cramps add 0.3 to 0.7g/L of salt to their drinks as a preventative tool. Others recommend adding sodium (3.0 to 6.0 g/L) to sports drinks based on the frequency of muscle cramps.Note: fluids and electrolytes are not immediately absorbed. Around 13 minutes is required to be absorbed into the circulatory system.

Prevention

• Neuromuscular training – there is strong support that the level of conditioning is a factor for the development of muscular cramping and that targeting the neuromuscular system can prevent this. The idea is to prevent neuromuscular fatigue. This could be done through plyometric and endurance training.
• Ingestion of water or a hypotonic sports drink an hour prior to competition ensures absorption.
• Maintaining hydration and adequate electrolytes aid in the prevention. Thus, fluids should be readily available throughout practices and competitions.
• A balanced diet is important to ensure fluid and electrolyte replacement.  

References

Minetto, M.A., Holobar, A., Botter, A. and Farina, D., 2013. Origin and development of muscle cramps. Exercise and sport sciences reviews, 41(1), pp.3-10.

Braulick, K.W., Miller, K.C., Albrecht, J.M., Tucker, J.M. and Deal, J.E., 2013. Significant and serious dehydration does not affect skeletal muscle cramp threshold frequency. British journal of sports medicine, 47(11), pp.710-714.

Miller, K. C., Stone, M. S., Huxel, K. C., & Edwards, J. E. (2010). Exercise-Associated Muscle Cramps: Causes, Treatment, and Prevention. Sports Health, 2(4), 279–283. http://doi.org/10.1177/1941738109357299