What it feels like: Sharp pain in the arch of the foot – may feel like the arch is drawing upward.
Why it happens: Cramping in the foot could be caused by an imbalance in electrolytes – chemicals in the body that regulate functions like muscle contractions. When you lose too many of these nutrients through sweat, the electrical impulses in your body can go haywire, leading to muscle cramps and spasms in the foot. Foot cramps can also signal muscular fatigue, as repeatedly flexing and extending the foot over the course of a longer race can cause muscles to work overtime, says Somerset.
The fix: Stand tall and still. Keeping your shoes on, shift your weight onto the cramped foot and press into it as much as possible. If it helps, focus on spreading your toes apart. Lift your opposite foot off the ground to stand on one leg if needed. Apply full body-weight pressure onto the affected foot for up to one minute.
What it feels like: Mild to severe pain or tightness in the calf.
Why it happens: There are two potential culprits, Fleming says: an electrolyte imbalance and shoes you are still transitioning into – particularly those with a lower “drop” (difference between heel height and forefoot height).
The fix: If you feel the cramp in your left calf, step your right foot forward and sink into a lunge with your front thigh parallel to the ground and front heel pressing down. Hold, then step your rear foot forward, walk four or five steps, and then repeat a few more times on the same side.
What it feels like: Intense, stabbing pain under the rib cage, usually on only one side.
Why it happens: According to exercise physiologist Dean Somerset, “Typically, if someone is cramping, they’re using muscles on that side preferentially over others that would contribute to breathing.”
The fix: While standing, take a few deep belly breaths, then press two fingers directly into the affected area. As you apply pressure, continue taking deep breaths and lean toward your opposite side from your hips. Hold for several seconds or until you feel the pain subside.