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Written by Dr. Carrie Smith PT, DPT
Exercise associated muscular cramps (EAMC) can be painful and hinder workout or race day performance. Many endurance athletes have experienced cramping in races, with up to 67% of triathletes and 50% of marathon runners reporting cramps (1). While this can be due to an underlying medical disorder or history of chronic disease (1), the primary culprits in EAMC are muscular fatigue and altered neuromuscular control (1, 2). Understanding how and why EAMC occurs will help you take preventative steps to avoid them in a race and have a plan to counteract them if do experience them during your event.
Many athletes refer to hydration and electrolyte status as a reason they are experiencing cramping. While these are essential factors for race performance and can lead to early fatigue if not addressed, they are no longer considered to be the primary cause of muscular cramping (1-3). In a sports setting, research has found that early muscular fatigue and “altered neuromuscular control” are the culprits (1, 2, 3). There are receptors within the muscle fibers that are constantly monitoring the amount of tension within the tissue, and disruption of the normal functioning of these receptors is thought to be the cause of EAMC. The muscle spindle fibers sense increased load in the muscle and signal the nervous system to reflexively produce a stronger muscular contraction. The golgi tendon organs (GTO) within the tendons monitor tension within the muscle and inhibit muscular contraction if the load becomes too high. Muscular fatigue causes an increase in muscle spindle fiber activity with a concurrent decrease in GTO activity, causing the muscle to spasm or cramp (1).
History of EAMC, history of previous injury, poor pacing strategies, not being appropriately trained for your event, poor posture and tight muscles are risk factors for cramping (1, 2). Here are some proactive strategies to prevent EAMC and reactive strategies if you do encounter cramping in your event or workout: Proactive plan:
Test for appropriate heart rate, pace and power ranges. Train with them and use them for your race pacing strategy to prevent early muscular fatigue that leads to EAMC.
VO2 and threshold testing can establish your individual ranges.
Monitoring for cardiac drift in longer course events can help confirm and dial in your pacing and hydration.
Know your fueling strategy.
Inadequate hydration may not be the cause of EAMC, but will lead to earlier fatigue.
Move well and load it.
After injury, athletes may develop compensatory patterns that cause them to favor one muscle group over another.
This leads to that muscle group fatiguing early because other muscles are not sharing the work.
Motor control exercises can train your nervous system to remember to incorporate all muscles meant for that movement and relieve excessive stress on any one group (4).
Adding resistance training to your movements strengthen your tissues and ability to rely on your new movement patterns under load.
Reactive plan:
If you do experience cramping during the race, isolated active stretching of the muscle group can alleviate the spasm.
This will slowly put tension on the GTOs and inhibit the muscle and allow it to relax.
Try pickle juice.
Small amounts of pickle juice have been found to decrease the duration of an active cramp (7).
Slow your pace.
Walk or soft pedal for several minutes.
Slowly build back into your pace, and try to avoid quick accelerations that would tax the muscle fibers.
Stop EAMCs before they stop you in your next race!
References:
Jun Qiu and Jie Kang. Exercise Associated Muscle Cramps - A Current Perspective
Schwellnus MP. Cause of exercise associated muscle cramps (EAMC)--altered neuromuscular control, dehydration, or electrolyte depletion? Br J Sports Med. 2009; 43(6): 401-408.
Armstrong S, Cross T. Exercise Associated Muscle Cramps. Medicine Today. 2013; 14(11): 62-66.
Wagner, T, Behnia N, Lau Ancheta WKL, Shen R, Farrokhi S, Powers C. Strengthening and Neuromuscular Reeducation of the Gluteus Maximus in a Triathlete with Exercise-Associated Cramping of the Hamstrings. Journal of Orthopedic and Sports Physical Therapy. 2010; 40(2): 112-119.
Hoffman MD and Stuempfle KJ. Muscle Cramping During a 161-km Ultramarathon: Comparison of Characteristics of Those With and Without Cramping. Sports Medicine - Open. 2015; 1(24): 1-9.