Inevitably, every runner experiences soreness. Soreness can range from some mild stiffness to struggling to walk down the stairs. More than likely, you have wondered to yourself, should you run if your legs are sore?
DOMS is the abbreviation for delayed-onset muscle soreness. You may not feel sore immediately after exercise. Instead, typically, you feel sore legs a day or two later – right when you are about to go on another training run.
Does Lactic Acid Cause Muscle Soreness?
Despite a persisting myth, lactate does not cause DOMS. Lactate is a by-product of glycolysis during moderate and high-intensity exercise. It used to be believed that this lactate became lactic acid, and that the accumulated lactic acid caused soreness in the muscles if it wasn’t flushed out.
However, we now understand lactate better. Lactate is shuttled out of the muscles and into the bloodstream during exercise and then taken to the liver. In the liver, some lactate is converted into glucose and then returned to the muscles to convert into energy. This process is known as the Cori cycle.
While some lactate does accumulate in the muscles at high intensities, it is not the cause of muscle soreness. Lactate will clear within a few minutes of stopping exercise. Experienced runners will also observe that they can be sore even when intensity (and therefore lactate production) is not high. For example, downhill running produces low levels of lactate, but can cause a large level of muscle soreness.
What Causes Sore Muscles from Running?
Think about the common scenarios where you have sore muscles: after a long run, a strength training workout, or downhill running. What do all of these scenarios have in common? The muscles have more time under mechanical load (time under tension).
Mechanical tension causes microdamage in the contractile units of a muscle fiber. (Some damage to the contractile proteins may also occur from elevated levels of intracellular calcium, caused by repeated muscle contractions.) For example, in a long run, the working muscles are under tension for multiple hours. In a strength training workout, you increase the mechanical load on the muscles. Downhill running involves eccentric muscle actions, which concentrate force in a smaller cross-sectional area of the muscle.
The microdamage in the muscle fiber produces a small level of inflammation, which stimulates pain receptors. What you feel from heightened activity in the pain receptors in muscle soreness. Additionally, your body produces more reactive oxygen species in response to the inflammation, which can damage surrounding muscle cells.
Exercise-induced muscle damage can exist without soreness. For example, you can have muscle damage after a marathon even if you are not sore. For many runners, muscle damage resulting in DOMS can be disruptive to training.
Should You Run if Your Legs Are Sore?
As with many things in running, the answer is dependent upon a few factors. The severity of your muscle soreness is a significant factor. If you have a light level of soreness, you can run through tired legs. If you are so sore that you struggle to get out of bed or sit down, then you may be best giving your body an extra rest day.
The context of sore legs also impacts the decision to run if your legs are sore. Should you run if your legs are sore during training? As long as the soreness is not severe and you can complete your planned workout without gait changes, yes. Should you run if your legs are sore following a race? You are probably better off extending your post-race recovery phase.
Can A Run Help Sore Legs?
If you have sore legs in training, you find that you actually feel better after a slow, short run. These runs – called recovery runs – can reduce the perception of soreness by encouraging blood flow to your legs. Blood flow brings nutrients to the damaged muscles, which can help them feel better.
However, a recovery run is not a substitute for rest days. Rest days allow full repair to occur, thus encouraging adaptation and reducing overall muscle soreness.
What If You Are Sore All the Time?
A well-programmed training plan should not leave you sore all the time. Even if you are marathon training, lifting weights, or running lots of hills, you should not be constantly sore.
Frequent soreness is a sign of one of two things (or both): you are training too hard, or your nutrition does not support muscle recovery.
Protein needs can be surprisingly high for endurance athletes. Dietary protein provides the substrate used to repair muscle damage. Without adequate dietary protein, the muscles are not quite fully repaired. Muscle damage accumulates more, and frequent soreness persists.
If you are sore after every weight lifting workout, or every speed workout, you likely are pushing too hard on those days. Focus on controlled pacing in speed workouts and scale down how heavy of weights you are choosing in your strength training workouts.
If you are constantly sore after long runs, you may be running too fast on those workouts. Insufficient fueling during long runs can also be a trigger for soreness.
Nutrition to Help Sore Muscles from Running
As mentioned above, eating enough protein will have a profound effect on muscle soreness. Generally, it is recommended that runners consume 20-40 grams of protein after exercise. However, protein needs extend past the post-workout window; your total daily protein intake will impact muscle protein synthesis. Based on your training volume, runners may need anywhere from 1.2-2.0 gram of protein per kilogram of bodyweight. To achieve this protein goal, you want to eat roughly 20-40 grams of protein at each meal, plus protein-rich snacks.
Recovery nutrition is not just about protein – you need to eat enough carbohydrates and total calories. As demonstrated in a 2023 study in the Journal of Physiology (which used trained female athletes), not eating enough total calories results in impaired muscle protein synthesis. The athletes had worse recovery, even with short-term low energy availability. Even if you get enough protein, not eating enough will cause muscle soreness.
Can Supplements Help with Sore Muscles from Running?
Once you cover the basics – eating enough carbs, protein, and total calories – there are some supplements that may aid in reducing muscle soreness during intense training periods. Omega-3 fatty acids, vitamin D, and tart cherry juice may have small benefits for athletes wondering should you run if your legs are sore.
Vitamin D supplementation may be beneficial in reducing DOMS. According to a 2018 review in International Journal Sport Nutrition and Exercise Metabolism, vitamin D supplementation will aid in recovery from exercise if you are deficient. Vitamin D plays a role in muscle protein synthesis via intracellular receptor activation. Deficiency in vitamin D will worsen muscle damage. A 2020 study in the Journal of the International Society of Sport Nutrition found if serum vitamin D levels were low, vitamin D supplementation reduced biomarkers of muscle damage that are frequently associated with DOMS after eccentric exercise.
Even if you run outdoors, you can have low vitamin D levels as a runner. However, do not blindly supplement. Before supplementing, have bloodwork done via your PCP, Quest, or Inside Tracker.
The research is still new, but omega-3 supplements may reduce soreness from running. A 2020 review in Nutrients points to the role of omega-3 fatty acids in enhancing recovery and reducing excess inflammation. These mechanisms lead to a reduction in DOMS. If you supplement omega-3, look for a product with at least 2000 mg of EPA and DHA. (I use Previnex’s Omega-3, which has high enough levels and no heavy metal contamination; use code LNR15 for 15% off your order.)
Tart cherry juice is another safe, effective supplement. The effect is small, but as demonstrated in a 2021 review in the International Journal of Sport Nutrition and Exercise Metabolism, tart cherry juice can help mitigate muscle soreness. If you use tart cherry juice, it’s important to actually get tart cherry juice – not sweetened cherry juice.
With any supplement, prioritize a high-quality supplement. (This article guides through how to choose supplements as a runner.) Remember that you can’t supplement your way out of a poor diet or mismanaged training load!
Does Foam Rolling Help if Your Legs Are Sore From Running?
While foam rolling may not cause muscles to repair more quickly, it may aid in lowering your perception of muscle soreness. Foam rolling places light pressure on the muscles. As a result, foam rolling may alter the neural excitability of the muscle. This effect may reduce the perception of muscle soreness.
Meanwhile, the research on massage guns (percussive therapy) and DOMS is mixed. Some research, such as a 2017 study in the Frontiers in Physiology, found that percussive massage may reduce muscle soreness. However, other studies are not as conclusive, such as a 2023 study in the Journal of Athletic Training. This trial found that a massage gun used after strenuous exercise only had a minor effect in reducing muscle soreness in active adults.
Ultimately, your individual response matters. If foam rolling or a massage gun helps you perceive soreness, then use them appropriately. However, if you do not notice a difference, skip them. If you benefit from foam rolling or percussive massage and are wondering should you run if your legs are sore, it may be beneficial to foam roll or massage gun gently before starting your run.
However, be careful not to use a foam roller or massage gun too aggressively. Too much mechanical pressure from these recovery tools can have the opposite effect – causing more inflammation and damage to the sore muscle, thus resulting in more soreness.
What Else Will Help Reduce Muscle Soreness from Running?
If you often find yourself wondering if you should run if your legs are sore, a few simple changes to your training will help.
Effective steps to reduce muscle soreness from running include:
- Sleep 7+ hours per night
- Eat enough carbohydrates, protein, and total calories
- Be consistent with your training – soreness can be triggered by a new stimulus
- Gradually increase training load, including mileage, intensity, and/or strength training
- Ensure you have at one complete rest day per week