Stiffness is the result of microtrauma in the muscle fibres. Following this injury, the body triggers a small inflammatory reaction in order to repair the muscle. This is what causes the localised and sometimes very incapacitating pain.
2. Why Does Stiffness Happen?
When we run, our muscles are called on for two distinct movements: the propulsion phase and the cushioning phase.
Scientists have demonstrated that the cushioning phase is the main cause of stiffness. This is why stiffness tends to occur more during downhill, high speed or very long distance running, as greater cushioning power is needed.
Be aware that the pain does not occur during exercise, but between 24 and 48 hours later.
A common misconception is that the build-up of lactic acid in the muscle causes stiffness.
3. The Benefits of Muscle Stiffness
Although severe stiffness can bring a halt to your training, feeling slight stiffness the morning after a big workout can be a source of motivation: it's proof that you worked hard!
Another, more concrete benefit is the overcompensation phenomenon. According to this theory, the body will be stronger on the days after heavy exercise. The damaged fibres will be rebuilt so as to make the muscle stronger and tougher. However, be careful not to abuse this phenomenon as you risk exposing yourself to injury: cramp, tendinitis, and tears.
4. How Can You Limit Stiffness?
The first factor for limiting stiffness is training. The more used to exercise the muscles are, the more they will stand up to stiffness. It is a good indicator of your fitness: if you feel stiff after each run, this means that your body has not yet got used to the movement of running or that your training sessions are too spaced out.
After a slightly more intense run than usual, it is best to seek cold rather than heat. A hot bath will dilate your blood vessels and amplify the inflammatory effect. On the other hand, some high-level athletes opt for cryotherapy to help them recover faster. Rest assured, you won't have to inflict ice baths on yourself! Directing the cold jet of the shower head onto your legs is enough to reap the benefits in terms of recovery.
The most obvious solution to get rid of stiffness is to rest. Every day, the intensity of the muscle pain will diminish. If this does not happen, it could indicate a more serious muscle injury.
To quickly eliminate stiffness, moderate exercise is recommended. "Warm-down" jogging is very effective. This doesn't mean linking quick sessions, but rather running at a gentle pace, even for a relatively short period of time (15 to 30 minutes) to reactivate the muscle and accelerate the reconstruction process.