Pop quiz: what is delayed onset muscle soreness (DOMS)? We'll fill in the blank for you if you're unsure. Basically, it's the soreness and slight weakness you feel after a really hard — or new — workout (and we mean at least 24 hours after [1]). Though some medical professionals say that it's unclear exactly what causes DOMS [2], typically, it's believed that eccentric movements [3], like squats and deadlifts, where you're lowering your body under control and essentially elongating the muscles cause microtears that lead to gradual inflammation [4].

Additionally, there are a wide range of suggested options for helping to treat sore muscles. Some studies rank ice over heat, some say to ice then heat, and others say that both impede recovery. The bottom line is, there are methods to help reduce the discomfort caused by DOMS, but there's really no surefire cure. You can read more about that here [5].

How Do I Treat Sore Leg Muscles?

Ah, the legs. Surely feeling DOMS in the muscles that help you sit, stand, and walk is not the greatest — you know how it's literally a pain to try and walk down stairs or even sit down in a chair — so we asked two physical therapists to break down what the best methods of treatment are. Both physical therapist Karen Litzy [6], DPT, and Perfect Stride [7] physical therapist Tyler Denn-Thiele, DPT, CSCS, named active recovery as an important way to help speed up the healing process. This can include light exercise like walking, cycling, light lifting, or stretching and mobility (try some yoga [8]!), Tyler said.

"Basically, it's anything that gets the heart rate up without placing a high load on the tissues," he explained, though he noted that if your muscle soreness is greater than a five out of 10 and does not go away with a warmup, you should not do that type of workout until the soreness has decreased. Here are other methods of treatment that they discussed:

• Foam rolling: This doesn't exactly speed up the recovery process, but it will temporarily (emphasis on temporarily) help relieve pain and increase range of motion after the fact because it increases blood flow to the muscles, both physical therapists said. Here is how to foam roll your calves [9], hamstrings [10], and quads [11].
• Compression garments: Tyler named compression boots [12] specifically.
• Massage: According to a meta-analysis of almost 100 studies [13], a 20- to 30-minute massage that is performed immediately following or up to two hours after exercise has been shown to effectively reduce DOMS. If you can't go to a professional (physical therapist or massage therapist), Karen suggested foam rolling as a form of self-massage.
• Immersion in cold water: This might not be super practical, but it's proven to have some effect [14].
• Heating pads: Tyler noted that heating pads can make you feel better in the short term, which might help some people get through DOMS, but they won't speed up recovery.

A Note on Nutrition and Sleep

Tyler said that proper nutrition and hydration are important to "give your muscles the building blocks they need to recover." Karen agreed. Both also suggested getting around seven or eight hours of sleep per night (which you should try to do [15] even if you aren't experiencing DOMS) because sleep will help your body [16] have the energy it needs to repair those muscles.

In terms of specific nutrition, Karen pointed to tart cherry juice [17] and, according to some small studies [18], protein-packed chocolate milk. Also, make sure you're staying hydrated with lots of water and eating a balanced diet.

Be Wary of Prolonged Soreness and These Red Flags

Tyler said that sore legs can be common for many recreational runners. He suggested asking yourself the following: "If you constantly have extreme soreness in the same area after different kinds of runs, my suggestion would be to figure out why. Is there something in your mechanics or current movement that is making you stress one side or muscle group more than another, or was your workout just targeting that area specifically?"

There are also certain warning signs to look out for with soreness. If you have profound weakness in your legs, Karen suggested seeking medical attention. Other red flags include bladder issues, like cola-coloured urine [19], which may indicate a rapid breakdown of skeletal muscle tissue [20] called rhabdomyolysis and could lead to kidney failure if left untreated. And, if DOMS persists for longer than five days after proper active rest and recovery, Tyler said to notify your doctor.