Muscle cramps from cycling: Why do they happen and how can you prevent them?

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Muscle cramps can be a debilitating and extremely unpleasant part of bike riding. So what causes them? And what can you do to prevent them from occurring?

Before we answer those questions, have you seen the film Pineapple Express? Stay with me here. There’s a scene where one of the main characters, Saul (played by James Franco) tries to kick out the windscreen of the police car he’s driving and gets his leg stuck.

That clip perfectly illustrates my drives home from early season bike races. At some point, usually on an anonymous piece of motorway, I’d suffer with leg cramps that would require me to get the afflicted leg as straight as possible. Easier as a passenger; more challenging as the driver.

The strange thing was, after a month or so of this, I would have no further issues and the motorways of Britain would be a safer place.

Let’s take a look at what the research says about cramps and why we get them.

Fluid and electrolyte imbalance

Ask most health care professionals how to prevent cramp and they’ll tell you to take on more fluids and make sure you replace lost salt and electrolytes. The evidence for this approach, though, seems mostly anecdotal and can be traced back 100 years or so to the Industrial Revolution.

Miners working in the hot and humid conditions of the pit reportedly suffered from muscle cramps. These were thought to be due to a loss of salt through excessive sweating and ‘water poisoning’; in effect, the dilution of the miner’s sodium concentrations through drinking large volumes of water.

The condition of the miners was improved in most cases by adding salt to their drinks. Stokers who worked on ocean liners suffered similar issues and were said to add sea water to their drinks in order to reduce the occurrence of cramp.

More recently it’s been shown that American football players, who historically suffered from cramps at hot pre-season training camps, demonstrated higher salt concentrations in their sweat versus those who had no history of cramping.

Additionally, increasing dietary salt intake has been shown to reduce cramps in tennis players who are experiencing issues practising in hot and humid conditions.

“But wait a minute,” I hear you say, “sometimes I cramp when it’s not hot and humid.” That’s certainly my experience too. Early season bike races in the UK tend to be held in bone-chilling cold rather than tropical heat.

Just a cursory viewing of this year’s London Marathon, which took place in relatively chilly conditions, will show you people were still experiencing muscle cramps. It would appear that whilst fluid and electrolyte balance are one potential cause of this issue, they are not the only one.

Staying hydrated is important, but it isn’t the only thing you should do to avoid cramping.

Exercise-induced muscle cramps

Exercise-induced muscle cramps seem to occur irrespective of weather conditions and fluid loss. Several studies have confirmed this.

In a trial looking at male runners before and after a marathon, no difference was found in fluid and electrolyte balance between the runners who suffered cramps and those who didn’t. In a South African study on Ironman triathletes, those who suffered from cramp had no significant difference in either percentage body mass loss or serum electrolyte concentrations. Post-race serum sodium concentrations were lower in the cramping group, but these were deemed to be within normal clinical ranges.

Interestingly, this research group also measured electrical activity in muscles that had cramped and compared it to those that hadn’t. They noted increased activity in the cramping muscles which they thought may be due to increased neuromuscular activity. More on the significance of this in a moment.

In a further study using more Ironman triathletes, subjects were surveyed before an event and asked questions about personal-best performances, current training loads and cramp history. The researchers found that athletes who experienced cramp during the event had exercised at a higher intensity during the race and had a faster overall time. This was despite having similar preparation and performance histories to those who didn’t cramp.

The researchers concluded that fatigue is a greater predictor of cramp than dehydration or serum sodium changes.

Neuromuscular fatigue

More recent theories about exercise-induced cramp have investigated fatigue-related disturbances in the neuromuscular system.

You’ll have likely found that the most reliable treatment for a cramped muscle is to stretch it immediately. It’s certainly our instinctive response. If one of the most reliable treatments for cramp involves adding tension to the afflicted muscle, then perhaps one of the underlying causes is a lack of tension. Or more precisely, a lack of tension on specific structures.

Embedded within the tendons of muscles are receptors called Golgi tendon organs (GTOs). The role of the GTO is to measure, feedback and reduce tension within the muscle when necessary. It’s thought that in the fatigued state there is a reduced inhibitory effect from the GTOs. The regulation of tension becomes unbalanced as the muscle is subjected to greater excitatory signals from the alpha motor neuron. Cramp eventually ensues. This theory is supported by the increase in electrical activity that has been demonstrated in cramping muscles.

It’s also been shown that muscles are more prone to cramp when in their shortened ranges. This is particularly true of two-joint muscles such as the hamstrings. It’s thought that the unloading of the GTO also plays a role in this effect.

Practical recommendations

So what steps can you take to reduce your risk of cramp?

1.Fluid and electrolyte imbalance

It goes without saying that preventing dehydration is important. It’s also probably worth making sure you are replacing lost salt, or at least not diluting your existing levels by solely drinking water. This is particularly relevant if you are riding in hot conditions, or know you are a salty sweater. Look for salt deposits on your skin or clothes as evidence of this.

Specific recommendations are difficult to make as we all lose salt at different rates but carrying some salty snacks with you, or adding a little more salt to your dietary intake, could prove useful.

Some riders sweat more than others.

2. Muscle fatigue

It’s no coincidence that most of us cramp more during early season races or when we’re attempting a particularly challenging ride. In this context cramping can be seen as a message that we need to improve our conditioning.

Studies looking at individuals who always cramp in the same muscles, usually in the later part of endurance events, have shown strength work can be effective in eliminating these type of occurrences. A strength training programme which begins by isolating the muscles involved in cycling is a good place to start.

3. Neuromuscular fatigue

Theories on the fatigue of the neuromuscular system as a likely cause of cramp don’t only give us an effective intervention, they also give us potential areas to focus on to avoid it in the first place.

Resistance train into vulnerable position

We know that muscles are more likely to cramp when taken into their short position. We can, however, train muscles to better tolerate these positions.

For example, two-joint muscles like your hamstrings may be prone to cramp when your hip is extended and your knee is flexed. If you find this to be the case then it’s likely you are also weak in this position. Applying resistance to these positions will not only reduce your risk of cramping but may have the additional effect of improving your performance on the bike.

Change positions on the bike frequently

It also seems that having muscles performing over the exact same length and tension for long periods may cause issues.

This is an indication you should switch up your position on the bike intermittently. Get out of the saddle now and again, drop your heels on the pedals to stretch your calves, straighten each leg fully, and push your pelvis towards the handlebars. Move between the brake hoods and the tops as appropriate as well.

If cramp strikes

If all else fails and cramp does strike, the best thing to do is gear down and attempt to keep riding. If this proves fruitless then you have no other option but to jump off and stretch the cramping muscle. Hold the stretch for 10 seconds or so and the cramp should pass. Repeat again if necessary.

What have you used to prevent or treat cramps? Have you ever used pickle juice? Let us know in the comments below.

About the author

Paul Argent is a former Category 1 road racing cyclist from the UK. He now runs an injury rehabilitation and sports performance business in the City of London, Human Movement, which specialises in helping chronically injured athletes and weekend warriors alike get back to doing the things they love better than ever. This article first appeared on the Human Movement website.

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