Is Muscle Soreness a Reliable Indicator of How Hard You Trained?

September 22, 2019

by Cathe Friedrich

No one likes the muscle stiffness and achiness you feel a day after completing a workout you’re unaccustomed to. Still, you might view those aches and stiffness as a sign that you trained hard and feel triumphant that you “aced” your workout. Some people see delayed-onset muscle soreness or DOMS as a badge of honor, an indicator they gave their workout all they had and anticipate results for their added labor. But is the degree of muscle soreness you feel a good indicator that you trained hard?

Delayed-Onset Muscle Soreness and Training Intensity

Delayed-onset muscle soreness or DOMS is the muscle stiffness and soreness you feel after pushing your muscles harder than usual. When starting out, almost everyone experiences DOMS, but as you continue to work out, your muscles adapt to the stress you’re placing on them and you no longer feel sore. However, a complete lack of muscle soreness can make you think you didn’t work hard enough. A little soreness gives confidence that you gave it your all! However, it’s important not to read too much into muscle soreness.

Where do the stiffness and achiness originate from? We don’t know exactly what causes delayed onset muscle soreness. The theory is that it’s a response to microtrauma to muscle fibers. The muscle fibers you worked so hard during strength training get damaged and torn and this leads to achiness in the muscles that comes on one to two days after a workout. What’s clear is the soreness comes from doing exercises you’re unaccustomed to or one where you do a workout, you’re used to in a manner that forces you to work harder.

Delayed onset muscle soreness is most pronounced after eccentric exercise, movements that emphasize the lengthening of a muscle against resistance. For eccentric movement, think of lowering a dumbbell during a biceps curl or running downhill. Some people do super-slow training where they reduce the tempo during the eccentric phase of the exercise to create more muscle damage. For some people, this leads to more pronounced muscle soreness. If you try this, chances are you will too!

However, delayed onset muscle soreness isn’t always a reliable marker of how hard you trained. For example, in studies when researchers ask people to rate their soreness on a scale from 0 to 5 or 0 to 10, the soreness they report doesn’t correlate well with the extent of muscle protein synthesis. Also, over time, the receptors that sense pain around the muscle can become desensitized, so you feel less pain after a workout. Pain receptors adapt to training along with your muscles.

Genetic Factors in Delayed Onset Muscle Soreness

Factors influence how sore you feel that you have no control over. For example, how much soreness you feel with a bout of DOMS depends partly on your genes. Two genes, ACTN3 and MLCK, are involved in delayed-onset muscle soreness, although there are other genes too. ACTN3 is a gene that produces proteins that offer speed and power athletes an athletic advantage in their sports. But studies also show that the proteins this gene produces protect against DOMS. So, if you have a gene form that makes you deficient in ACTN3 proteins, you experience more pronounced post-workout soreness than someone who has enough of these proteins.

Gender Differences in DOMS

Another factor that impacts how sore you feel after a tough workout is your gender. Research shows that women may experience less severe DOMS symptoms than men, all other things being equal. Are women just tougher than men? Increased pain tolerance may come from higher levels of estrogen in women.

For example, one study looked at whether birth control pills impacted delayed onset muscle soreness in women. Birth control pills contain estrogen and women on them have higher levels of estrogen circulating in their bloodstream. What they found was women taking birth control pills who did eccentric exercise experienced lower levels of creatine phosphate, a marker of muscle damage. The hypothesis is that estrogen may protect muscle cells against damage. A 2000 study also found that women have a less pronounced inflammatory response relative to men, despite sustaining similar degrees of muscle damage. Therefore, women may have less post-workout pain than men when they do an unaccustomed workout. Estrogen may be at play here too.

Differences in Pain Tolerance

Irrespective of gender, we all have different degrees of pain tolerance. So, it’s hard to judge the success of a workout by the extent of muscle soreness. In fact, soreness is not a prerequisite for muscle growth. Studies show that up to a third of people who do heavy, eccentric-oriented exercises don’t experience delayed onset muscle soreness. Therefore, we can’t correlate soreness with muscle protein synthesis and muscle growth.

On the other hand, a little soreness now and then can be a sign that you’re challenging your muscles and that’s a requirement for continued muscle hypertrophy and strength gains. If you never feel sore, you might question whether you’re pushing yourself hard enough. However, if you feel sore most of the time, you might be pushing too hard and interfering with your muscles’ ability to recover.

The Bottom Line

Feeling sore after a workout suggests you’ve worked your muscles harder than they’re accustomed to or worked them differently. However, a lack of delayed onset muscle soreness doesn’t mean you aren’t training hard enough to get results, but if you never feel sore, you might question whether you’re using progressive overload and whether you’ve reached a plateau. A complete lack of soreness might mean you need to shake things up by changing training variables, like intensity or volume, or by introducing new exercises. Don’t let your workouts become stagnant. You’re doing it to get results and make the best use of your time.