Original episode & show notes | Raw transcript
For decades, athletes were told that muscle cramps were a simple issue of dehydration and electrolyte loss. However, as the podcast details, contemporary sports science now views Exercise-Associated Muscle Cramps (EAMCs) as a much more complex, primarily neuromuscular issue. This means the problem originates not just in the muscle itself, but in the nerves that control it.
The podcast specifically focuses on EAMCs, distinguishing them from other types like nocturnal cramps (which happen during sleep) or pathological cramps (which are symptoms of underlying medical conditions).
The discussion highlights several factors associated with a higher risk of cramping. It’s important to note these are correlations, not necessarily direct causes.
Greater Biological & Training Age: Older athletes and those with many years of training experience seem more prone to cramps.
Family History: A genetic predisposition may exist, suggesting some individuals are simply more susceptible.
High Intensity & Duration: This is perhaps the most significant predictor. Cramps often occur when an athlete pushes harder or longer than their body has been trained for. The relative intensity is key.
Fatigue: This is the central pillar of modern cramp theory. A fatigued neuromuscular system is one that is prone to malfunction.
Stretching Habits: Interestingly, one study noted that less time spent stretching is a risk factor. This points towards the importance of muscle tension and neural signaling.
The classic advice to “drink more and take a salt tab” is now largely considered outdated as a primary explanation for EAMCs.
The Time Course Mismatch: If you take an electrolyte supplement or drink pickle juice, any cramp relief is often felt within minutes. However, it takes 20-30 minutes or more for those electrolytes to be absorbed from your gut into your bloodstream and have a systemic effect. This timing doesn’t add up. The rapid relief suggests a different mechanism is at play.
The Systemic Danger: Your body maintains a very precise balance of electrolytes (like sodium, potassium, and chloride) across cell membranes. This balance creates a “membrane potential” essential for the function of all cells, including nerve and heart cells. If sweating caused a significant enough shift in this balance to make your leg muscles cramp, it would imply a dangerously unstable state for your entire body, which is not what happens. The body is very effective at preserving this systemic balance.
The current understanding is that EAMCs are caused by a breakdown in the communication between the nervous system and the muscles. Fatigue is the trigger that causes this system to malfunction.
This theory proposes that the cramp originates from an imbalance of signals at the spinal cord level. Your muscles are controlled by a feedback loop involving two key sensors:
Muscle Spindles (The “Go” Signal): These are embedded within the muscle fibers and detect stretch. When activated, they send an excitatory signal to the spinal cord, telling the muscle to contract.
Golgi Tendon Organs (GTOs - The “Stop” Signal): These are located in the tendons and detect the level of tension on the muscle. When tension gets too high, the GTO sends an inhibitory signal to the spinal cord, telling the muscle to relax to prevent injury. The podcast uses the analogy of a car’s rev limiter.
The Theory: As you become fatigued, this system gets out of balance. Muscle spindle activity increases (more “go” signals), while GTO activity decreases (fewer “stop” signals). The result is a runaway positive feedback loop of contraction, leading to a cramp.
This theory elegantly explains why stretching is an effective immediate remedy. By forcefully stretching the cramped muscle, you are manually increasing the tension on the tendon, which powerfully activates the GTOs, sending a strong inhibitory “relax!” signal that breaks the cramp.
This theory suggests the problem is more localized, occurring at the “neuromuscular junction”—the point where the very end of the motor nerve meets the muscle fiber.
The Theory: Fatigue causes abnormal excitation of the terminal branches of the motor nerve. This could be due to a number of factors related to the local cellular environment, such as a problem with re-absorbing key signaling molecules (like calcium or acetylcholine) after a contraction. Since muscle relaxation is an active process that requires energy, a fatigued muscle may simply have trouble completing the relaxation phase, leading to a sustained, involuntary contraction.
Understanding the neuromuscular theories allows us to see why certain interventions are effective.
The podcast discusses using substances with strong, pungent flavors like hot sauce (Tabasco, Cholula), pickle juice, mustard, or even extremely sour candy (Warheads).
The Mechanism: This is not about the salt or calories. These substances act as powerful stimulants for a set of nerve receptors in your mouth and throat called Transient Receptor Potential (TRP) channels. When these nerves are strongly activated by the intense taste, they send a powerful neurological signal up to the brain and down the spinal cord. This massive sensory input effectively “resets” the malfunctioning motor neurons, overriding the cramping signal and causing the muscle to relax.
Application: The hosts suggest sipping on a “Tabasco scratch” mix when you feel a cramp coming on, or taking a shot of pickle juice or a hot sauce packet for immediate relief.
Since fatigue and exceeding your trained capacity are the biggest triggers, the most effective prevention is highly specific training.
Train for the Demands of Your Event: If you cramp in races with lots of surges, you need to train with surges (e.g., repeated sprint workouts, practice races). If you cramp three hours into a long ride, you need to do long rides that incorporate race-level intensity deep into the ride. The goal of these “cramp induction rides” is to push your neuromuscular system to adapt to that specific stress.
Positional & Bike Specificity: As the podcast notes, if you train on a road bike but race on a mountain bike, you are using your muscles (adductors, glutes, core) in a slightly different way. This new pattern can cause fatigue and cramps in muscles that are otherwise strong. The solution is to spend more time training on your race-specific equipment.
Strength Training: Targeting muscles that are prone to cramping with specific exercises (like Copenhagen planks for the adductors) can increase their fatigue resistance.
Heat Acclimatization: Heat and humidity dramatically increase the relative intensity of an effort. A 250-watt effort in 95°F humid weather is far more stressful on the body than the same effort in 60°F dry weather. If you reliably cramp in the heat, dedicated heat training can be a powerful tool to reduce that relative strain.