stitch
What is it?
Around 70% of runners have experienced a stitch at one time or another. There are two main types of stitch: the diaphragm stitch is triggered by a rapid increase in breathing rate, while the high-colon stitch is set off by eating too much or too close to exercise.
Stitches are common in new and inexperienced runners, and pain can be intense enough to slow you down or force you to stop.
How does it occur?
A stitch is a build-up of lactic acid in the muscle. Diaphragm stitches result from strain placed on the dome-shaped muscle of the diaphragm, which during a run is jostled between the lungs and the internal organs of the abdomen that it supports. When your foot strikes the ground, the movement forces heavy organs such as the liver downwards, while exhalation pushes the diaphragm sharply upwards. Running downhill or suddenly picking up the pace can exacerbate the condition.
A high-colon stitch occurs when a run interupts the digestive process. During a run, blood is diverted to the heart and limbs, and if there is food in the stomach, the gut can react by cramping.
How to treat it
A stitch will often go quickly if you change your pace or stop, but other techniques can alleviate the pain. Deep "belly breathing" with pursed lips can help, as can exhaling as the leg opposite the stitch hits the ground. Bending forward at the waist and pressing your hands on the point of the stitch also works well, but involves stopping.
How to avoid it
Increase speed gradually and try to avoid shallow breathing. Allow at least 2 hours between eating and running, and avoid unfamiliar, low-fibre, high-fat foods before a run. Taking on plenty of water and energy drinks will aid digestion and prevent dehydration, helping you to avoid digestion-induced stitches.