Muscle Cramps: Causes, treatment, and what to do about it
- Giulia Pline
- Aug 23
- 3 min read
A muscle cramp is the sudden, involuntary tightening of a muscle that can stop you in your tracks and cause immediate discomfort. “Charley horse" is a slang expression that is often to describe a muscle cramp.
Muscle cramps can occur at different times for different reasons including electrolyte imbalances, issues with circulation, nerve sensitivity, and muscle fatigue. In this blog post we will cover the most common causes of muscle cramps, why they happen, and what you can do to help.
Muscle cramps during exercise, also called exercise-associate muscle cramps (EAMCs) can be painful, disruptive, and just plain frustrating. They usually occur in a specific area, like the calf or hamstring, and feel like sudden, involuntary muscle contractions or spasms.
Common reasons you might get an EAMC include:
Lack of conditioning: undertrained/not prepared to meet the exercise/task at hand
Depletion of muscle energy stores (the fuel your muscles need to function and produce movement)
Imbalances in training such as training certain movement patterns or muscle groups more than others, or overtraining
*Active insufficiency: when a muscle contracts in a position where it is maximally shortened
*Cramping due to active insufficiency is common during certain exercises. Let's use a hamstring cramp during a hip bridge as an example to explain it.
Ever gotten a cramp in your hammies during a hip bridge? Here's why:
The hamstrings originate at the ischial tuberosity (sit bone) and attach to the tibia and fibula (bones of the lower leg), crossing both the hip and knee joints.
Their job is to extend the hip and flex (bend) the knee.
In a bridge position, you’re extending the hip and flexing the knee at the same time, which places the hamstrings in their most shortened position.
When this happens, the sarcomeres (or the tiny contractile units inside your muscle fibers) are overlapping more than usual. This reduces the muscle’s ability to generate force efficiently and makes it more likely to cramp.
While these cramps can be uncomfortable, your body can adapt over time. With repeated exposure to the same movement and position, cramping usually decreases as your muscles become better conditioned to contract in that range of motion.
Aside from active insufficiency, there are two main theories as to why cramping happens.
The first theory is the neuromuscular control theory.
Neuromuscular junction
In each of your muscles there are sensory receptors called muscle spindles which detect muscle length (stretch), and velocity (speed), of muscle contraction. There are also receptors at the junction between your muscles and tendons (tendon connects muscle to bone) called golgi tendon organs which detect load or tension applied to a muscle. Muscles are innervated by motor neurons which send signals from the brain to the muscle to produce movement.
Neuromuscular control theory purports that when a muscle become fatigued, the muscle spindles which are excitatory tend to send stronger signals than the golgi tendon organs which are inhibitory, leading to an imbalance in signaling between the brain and the muscle. This causes the motor neurons in the muscle to become overactive and leads to the muscle contracting involuntarily, aka your cramp.
The second theory is electrolyte depletion.
These types of cramps usually occur in more than one muscle due to large amounts of sweating, dehydration, and electrolyte disturbances that alter neuron firing to your muscles. Cramping due to electrolyte depletion can also happen due to certain medications or medical conditions. Global cramping is a more severe type of cramping that may warrant medical attention.
So what can you do to help an isolated cramp?
If your cramp is isolated and not a more global/multi-muscle type of cramping, stretching can help. Stretching helps reduce the overactivity in the muscle spindles and sends inhibitory signals to the brain that allows the muscle to relax.
Some studies have even used stretching as an intervention to reduce nocturnal cramps, or the kind of muscle cramps that wake you up at night. These types of cramps can be due to certain medical conditions, medications, dehydration, and even muscle fatigue.
Can you prevent cramps?
You can definitely take steps toward reducing your risk of cramping. Warming up before exercise, regular conditioning and training, and adequate hydration and electrolyte balance can all help mitigate your chances of cramping up.
If your muscle cramps If cramps are frequent, severe, or persistent, or if they’re accompanied by weakness, swelling, or numbness make sure to check in with your doctor about any underlying medical conditions such as circulation issues, nerve compression, or side effects to medication.
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