Muscle Cramps

aka a “Charlie horse” (Australia and USA) or a “Chopper” (England)

Are you stuck within a confusing cycle of fear of movement, reduced fitness and increased cramping frequency? Cramping after or during exercise can have significant effects on mental health and confidence when trying progressive exercise due to a sense of “no control” or fear of serious muscle injury or the unpleasant feeling of a cramp. Unfortunately, many also waste their time with outdated cramp reduction strategies (Sodium Intake Beliefs, Information Sources, and Intended Practices of Endurance Athletes Before and During Exercise - PubMed (nih.gov) + Certified Athletic Trainers' Perceptions of Exercise-Associated Muscle Cramps). Understanding the latest facts about muscle cramping should alleviate this concern and give you back some control and agency over difficult exercise.

How common? 

• 40% of people will experience cramping in their lifetime (Muscle cramp: main theories as to aetiology). 

  
  

Clues or common symptoms?

• A muscle cramp has been described as a short-term (seconds to minutes long), sudden involuntary contraction of skeletal muscle. They can occur at rest, such as at night or during/post-exercise. Being seemingly involuntary likely influences reports of cramps being painful. Also, fear of injury due to cramping is common, although there is no evidence that cramping worsens muscle health or causes muscle strains.  

  
  

What is wrong when I cramp? 

• Early theory was that cramping was due to reduced minerals (called electrolytes: particularly sodium, chloride, magnesium, and potassium) during exercise, due to reports of cramping increasing in sweating laborers during hot working environments (Heat cramps - Google Scholar). Sports drink and supplement marketing have been very successful at profiting from that concept. However, despite feeling effective, when sweat management and electrolyte management have been implemented in a controlled scientific setting, they are not measurably effective (Muscle cramps: A comparison of the two-leading hypothesis + Does a Reduction in Serum Sodium Concentration or Serum Potassium Concentration Increase the Prevalence of Exercise-Associated Muscle Cramps?). To add to this, we have further research to account for problems with this theory, including:

• When you sweat, you lose more water than salt or other minerals, so your body still has higher concentrations of salt and other minerals than it does of water. Salt loss is not significant enough to cause cramping in a single muscle group (Significant and serious dehydration does not affect skeletal muscle cramp threshold frequency).  

• Newer studies have not seen electrolyte deficiency during exercise events causing cramping (Muscle Cramping in the Marathon + Three percent hypohydration does not affect threshold frequency of electrically induced cramps + Serum electrolyte concentrations and hydration status are not associated with exercise associated muscle cramping). 

• Cramping occurs in some muscles, whereas sweating and “electrolyte loss” occur in all muscles during exercise. Cramping in all muscles is rare during exercise. This mostly occurs in medical contexts that can be explained by neurological, pain, medication or fatigue-related reasons rather than lacking electrolytes (Nocturnal leg cramps and prescription use that precedes them: a sequence symmetry analysis + Experimental muscle pain decreases the frequency threshold of electrically elicited muscle cramps).  

• Cramping can occur just as frequently without sweating or in high-temperature environments for example: 

  • Cramping at night or,

  • Foot or finger cramping from repetitive, fatiguing movement. Used to be common in typists, but this sort of cramp has reduced as keyboards are much less fatiguing to use. 

• Rather, our theories have shifted towards focusing on fatigue as the cause of cramp for those at risk (Aetiology of skeletal muscle 'cramps' during exercise + Exercise-Associated Muscle Cramps in the Tennis Player). 

  • We know fatigue is more important to focus on modifying than electrolyte drinks due to: 

    • Faster, longer or inclined running or having a history of injury (likely indicating presence of pain and/or poorer fitness) predicts cramping better than sweat losses (Increased running speed and pre-race muscle damage as risk factors for exercise-associated muscle cramps in a 56 km ultra-marathon + Predictors of calf cramping). 

    • Cramping occurs in the muscle you use during exercise (Task-specific dystonias), especially muscles that cross two joints like the calf muscles (cross the knee and the ankle) or the hamstrings (cross the hip and the knee joint) (Elicitability of muscle cramps in different leg and foot muscles). Sweat loss occurs across all areas of the skin, rather than just around the muscle you use.

    • Pickle juice can stop a cramp within a minute of it entering your mouth (Ingestion of transient receptor potential channel agonists attenuates exercise-induced muscle cramps). The salt content in pickle juice cannot explain this. More about pickle juice is explained later. 

  • So, what is going on in the fatigued muscle during a cramp? In brief, two parts of your muscle, when fatigued, behave in a two seemingly funny ways, 1) your muscle has deep “spindle” fibres that trigger muscle contraction when the tendon of that muscle is suddenly lengthened. This reflex explains what you feel when your knee kicks out uncontrollably when a physio or doctor taps a “reflex” hammer on the knee tendon. When these spindles of your muscle fatigue, they temporarily cause the muscle to contract, causing a cramp, their reflex cannot be turned off, causing the muscle to remain contracted. 2) Your muscles also have a deep structure called the “golgi-tendon organ” that, when activated, relaxes your muscles, such as when your leg feels like jelly or collapses after hard exercise, or when someone kicks the back of your knee suddenly. When fatigued, contributing to a cramp, this second reflex cannot turn on to relax the muscle. So, the fatigue of two structures in the cramping muscle, the “contract reflex” in your muscle is stuck on, and the “relax reflex” in your muscle is stuck off, causing a temporary cramp, that resolves when rested, or when fatigue signals in your nervous system are interrupted (Reflex inhibition of normal cramp following electrical stimulation of the muscle tendon). Prevention strategies aim to prevent this process from occurring, and symptom management strategies aim to turn off or interrupt these stuck muscle reflexes. 

(Exercise-Associated Muscle Cramps in the Tennis Player)

• “But…..”

  • “When I take xyz… my cramp resolves.” 

    • Did you also rest and practice relaxation while taking the XYZ supplement? Rest and relaxation can be beneficial for cramps.

    • The ritual of drinking anything is a relaxing experience. Think about when you drink something. It's like a 5 to 10-second ceremony of uninterrupted bliss. Reaching for your drink, bringing it to your mouth, drinking, enjoying the feeling of the drink, and then putting the drink down. Benefits of this 5 to 10 seconds mental switch off last for up to 5 minutes, conveniently and potentially impacting cramp resolution within that time as your fatigue reduces (A drink of water can improve or impair mental performance depending on small differences in thirst + Water ingestion improves subjective alertness, but has no effect on cognitive performance in dehydrated healthy young volunteers). 

    • Salt takes too long to enter your system, so it cannot have any short-term benefits, and salt levels in your blood do not predict cramping onset, as explained already (What is sodium?). 

    • We do not encourage stopping all hydration practices that you have attempted or completed, even if they have resolved your cramping. But, please be aware that your hydration practices may not benefit others like you think they do. 

  • “I cramp in the summer when I sweat a lot.” 

    • Do you start your pre-season or exercise more than usual in the summer? You have a lower fitness level than you did 3 months ago, after completing more training, and notice that the cramping frequency had reduced back then. Although this coincidentally suggests that individuals who initiate an electrolyte routine, while increasing their weekly training volumes and becoming fitter, experience improved cramping tolerance, the fact is you're just getting fitter (Exertional heat illness and environmental conditions during a single football season). 

    • Heat can affect fatigue independent of hydration (Heat Cramps | Semantic Scholar) but cramping still occurs in winter sports environments (Medical Complaints After a Marathon Run in Cool Weather). Also, perhaps paradoxically, exercising more in the heat over time can improve acclimatisation, and reduce heat fatigue during exercise in hot environments (Benefits of heat re-acclimation in the lead-up to the Tokyo Olympics). 

  • “I am a salty sweater.”

    • Yes this is possible but again, mineral losses in sweat at any amount does not predict cramping (Sweat Characteristics of Cramp-Prone and Cramp-Resistant Athletes + Sweat Characteristics in Individuals With Varying Susceptibilities of Exercise-Associated Muscle Cramps), and being a salty sweater would mean as you sweat and lose more salt than another, you still lose more water than salt, leaving plenty of salt still in your system. Low body salt levels are more likely to cause a heart condition than cause cramping (Exercise-Associated Hyponatremia). 

    • Additionally, your body regulates salt levels effectively. If you increase the intake of salt to account for being a “salty sweater”, you’ll likely sweat or urinate more salt out anyway (Impact of 3-day high and low dietary sodium intake). 

      
      

What can you do about it? How can you prevent cramps altogether or just increase the amount of exercise you can do before a cramp starts?

There is still a lot we don’t know about cramping. We do not have 100% cures or absolute promises. Some individuals feel they can predict when they will cramp, while others find it difficult to predict when they will occur, making it a challenging area for evidence to highlight. It's hard to induce cramps intentionally for most people, so it's hard to study what stops them. Not everyone that exercises and gets fatigued will cramp either, so there is likely some genetic influence to someone's threshold to cramping prior to doing any prevention strategies (Collagen genes and exercise-associated muscle cramping). However, what we do know is there are some common prevention or symptom-control strategies you can implement to get control of cramps back and reduce their frequency over time.

• “Prevention is the best cure.”

  • Training

    • Get fitter over time or habituate your muscle to position, modes of exercise, or speeds that fatigue them quickly w

  • Strength train

    • Weakness might be a surrogate measure for easily fatigable muscles. Strength training the cramping prone muscle in cramp like positions has been seen to be helpful (Strengthening and neuromuscular reeducation of the gluteus maximus in a triathlete with exercise-associated cramping of the hamstrings + Muscle Cramping in the Marathon: + Effects of resistance training on neuromuscular characteristics and pacing during 10-km running time trial).

      • Calf cramps? Add some heavy dumbbells or machine calf raises to your gym routine, emphasising the part of the movement that makes the calf feel like it is about to cramp.

      • Hamstring cramps? Add some seated hamstring curls (emphasising the part of the movement that makes the hamstring feel like it is about to cramp) and single-leg floor touches to your gym routine. 

      • Quad/thighs cramps during extended downhill running or walking? Add some lunges, step-ups, or single-leg knee extensions/kicks to your gym routine while making sure you emphasis the lowering phases of each quad movement.

• Speak to your GP about any medications that might affect your cramping threshold, or improve your medical condition to the point where you need less of these medications, if realistic. 

• Consume a healthy, varied plant-based diet but avoid mineral madness. Yes, this could include potassium, magnesium, and salt-rich foods, but don't mistake this for direct influence on cramp risk. It is more likely to support adapting well to exercise over time and becoming more fatigue-resistant. 

  • Creatine supplementation has been shown to be helpful for cramp frequency due to its effects on reducing the rate of fatigue during exercise (Creatine supplementation during college football training does not increase the incidence of cramping or injury + Creatine monohydrate treatment alleviates muscle cramps associated with haemodialysis + Method Health- Creatine). 

  • Consuming adequate carbohydrates prior to and during prolonged exercise offsets rates of fatigue, so it can be helpful for reducing cramp occurrence (Muscle Cramping During Exercise: Causes, Solutions, and Questions). This also might be why salt intake prior to exercise might be helpful, through delaying fatigue occurrence, rather than preventing electrolyte depletion (The effect of carbohydrate and salt oral stimulations on central fatigue).

• Improve or prioritise more sleep. This is one of the best strategies anyone could offer to improve recovery from fatiguing exercise (Sleep Health and Habits).

• Practice regular stress management to enhance recovery from cramp-inducing activities, much like sleep is beneficial for overall well-being. We all know how fatiguing lots of stress can be.

• Stay positive and optimistic. In the long term, getting fitter and improving lifestyle factors to enhance tolerance to exercise is helpful. However, in the short term, the side effect of more training is fatigue, so cramping might still occur. This is not a bad thing, and potentially cramping is a way to know how much exercise you are habituating to or becoming more cramp resistant (Cramp Training Induces a Long-Lasting Increase of the Cramp Threshold Frequency in Healthy Subjects).

  
  

How long will it take?

• Often, lifestyle and exercise habits will take months prior to feeling helpful, so be optimistic about the long-term benefit of progressive exercise and other lifestyle changes on your fatigue and cramp tolerance. 

  
  

Cramp symptom management. What do do when you have a cramp.

• "Rest is best" is one of the few medical contexts where rest is similarly beneficial compared to tolerable exercise, to reduce fatigue quickly in the cramping muscle. Active recovery (walking around) or passive recovery (sitting relaxed) seems equally helpful (Effects of Passive or Active Recovery Regimes - Sports Medicine). However, for some cramping experiences and in some sports contexts, you can’t just rest, so slightly less helpful options are:

  • Stretching- often a very appropriate instinct to feel being helpful when we cramp, aims to relax the muscle reflex systems and can be effective for some (Acute Passive Static Stretching and Cramp Threshold Frequency + The influence of muscular lengthening on cramps). Historically, it’s likely before we studied the effects of stretching on cramp that old-school thought to “stretch after exercise” might have originated from “common sense”. However, despite being helpful during cramp, stretching does not help prevent cramps (Prophylactic stretching does not reduce cramp susceptibility) and your muscle flexibility does not predict cramp risk (Increased running speed and pre-race muscle damage as risk factors for exercise-associated muscle cramps in a 56 km ultra-marathon + Predictors of calf cramping). 

  • Massage. You might see this in football or soccer on the sidelines, the physio giving a cramping player a quick massage. Massage likely does not relax the reflex fatigue, like stretching does, but likely works through “counter-stimulation” and relaxation (A modern way to teach and practice manual therapyt). Massage seems to act as a distraction from the cramping sensation, helping you relax and rest, but before exercise has not been shown to prevent cramps (The Effects of Massage Therapy on Sport and Exercise Performance: A Systematic Review). 

• Pickle Juice (or any harmless yet noxious tasting food/drink like vinegar, wasabi, mustard, chillis) (Ingestion of transient receptor potential channel agonists attenuates exercise-induced muscle cramps).

  • You do not need to drink pickle juice for it to be helpful, because you don't need to get electrolytes to your muscles. Swishing or putting something in your mouth that elicits a feeling of needing to gag activates a pathway from your mouth to your brain and spinal cord that then travels to relax the troubling reflex behaviour of your cramp muscle (Reflex inhibition of electrically induced muscle cramps in hypohydrated humans). We know similar mouth-nervous system pathways also explain why when you swish carbohydrates in your mouth, without ingestion, causes a small increase in exercise tolerance/performance (Carbohydrate sensing in the human mouth: effects on exercise performance and brain activity).

  • Unfortunately, this strategy still does not help everyone compared to just resting (Effects of TRPV1 and TRPA1 activators on the cramp threshold frequency). 

Busting Myths?

• What's not encouraged for prevention or management of symptoms. 

  • Quinine has been prescribed in the past but is no longer likely to be given due to common strong side effects (Quinine for muscle cramps | Cochrane). 

• What does not help?

  • Magnesium supplements have not been shown by good evidence to help prevent cramps (Magnesium for muscle cramps | Cochrane + What is the role of magnesium for skeletal muscle cramps? A Cochrane Review summary). 

  • Salt supplements likely are not absorbed quick enough to be helpful for cramp symptom reduction (Effects of Sodium Intake on Health and Performance in Endurance and Ultra-Endurance Sports + Sodium Intake During an Ultramarathon Does Not Prevent Muscle Cramping, Dehydration, Hyponatremia, or Nausea). Also again, salt levels do not predict cramping onset despite popular opinion (Muscle Cramping During a 161-km Ultramarathon: Comparison of Characteristics of Those With and Without Cramping). 

  • Potassium-filled food like bananas are also likely not helpful for cramp relief as they do not enter the system fast enough to be helpful for cramp symptom management (Plasma potassium concentration and content changes after banana ingestion + The effect of osmolality and carbohydrate content on the rate of gastric emptying of liquids). 

    
    

What can Physio at Method Health offer? 

• We can offer individualized advice to help tailor a cramp training-based exercise program at a specific dosage you can tolerate, and guide you to a realistic progression plan each week. We can also provide you with individual advice on the best strength exercises to target your cramp-prone muscle groups, which you can incorporate into your weekly routine.

• We can be your support crew to encourage lifestyle changes that can improve your general health, such as coaching you on sleep, guiding you through ways to reduce mental stress, or adding things to your life to better cope with stress, potentially affecting your fatigue during exercise or when recovering at night. 

• Suppose you have had persistent cramping and are very confused about why you still have it. In that case, we can help you make sense of the cramping risk factors, highlight management areas to prioritise or be more optimistic about, and provide you with individual guidance to assist in managing and resolving your cramp risk.