Muscle soreness is one of the most noticeable consequences of resistance training. You finish a difficult workout, wake up the next morning, and suddenly sitting down, walking downstairs, or reaching for something on a shelf reminds you exactly what you trained the day before.
Because soreness is so easy to feel, it is also easy to use it as a measure of workout quality. If your chest is sore after training, you might assume you had a great chest workout. If you feel nothing after training your legs, you might wonder whether you trained hard enough.
There is some logic behind this. Soreness can provide information about the stress placed on a muscle. However, it is a much less reliable indicator of workout quality, muscle growth, or recovery than many people assume.
Understanding what causes soreness—and what it actually tells us—can help us interpret it without either chasing it or unnecessarily worrying about it.
What Causes Muscle Soreness?
The soreness that develops after unfamiliar or demanding exercise is generally referred to as delayed onset muscle soreness (DOMS). It typically develops several hours after exercise, often becomes most noticeable around 24–48 hours later, and gradually resolves over the following days.
DOMS appears to result from a combination of processes that occur after exercise rather than from one single mechanism.
Resistance training, particularly unfamiliar or mechanically demanding exercise, can produce microscopic disruption to muscle fibers and surrounding structural components. These are sometimes casually referred to as “microtears.” This microscopic tissue disruption is very different from a major muscle tear or injury, but it can initiate a cascade of events associated with the soreness experienced after training.
The body responds to exercise-induced muscle damage with an inflammatory response. Immune cells and inflammatory signaling molecules become involved in clearing damaged material and coordinating tissue repair and remodeling. Changes in the local chemical environment can sensitize nociceptors—the sensory receptors involved in detecting potentially damaging stimuli—which contributes to the tenderness and discomfort associated with DOMS (Cheung et al., 2003; Peake et al., 2017).
Importantly, soreness does not simply represent the physical tearing of muscle fibers. DOMS appears to be a multifactorial phenomenon involving mechanical disruption, inflammation, swelling, changes to the extracellular matrix, and increased sensitivity of sensory nerve endings (Cheung et al., 2003; Peake et al., 2017).
This also explains why soreness is usually delayed rather than occurring immediately during exercise.
Some Types of Training Produce More Soreness Than Others
Not every exercise or training style produces the same amount of muscle damage or soreness.
One of the most consistent observations in the literature is that eccentric muscle actions—when a muscle produces force while lengthening—can be particularly potent drivers of exercise-induced muscle damage and DOMS, especially when they are unfamiliar or heavily loaded (Proske & Morgan, 2001).
Think about slowly lowering a dumbbell during a curl, descending during a squat, or controlling the lowering portion of a Romanian deadlift. These are all eccentric muscle actions.
This does not mean that every eccentric repetition causes substantial muscle damage. Rather, high-force and novel eccentric loading appears particularly capable of producing it.
Training muscles at longer muscle lengths may also increase the likelihood of muscle damage and soreness. Exercises that place substantial resistance on a muscle while it is highly lengthened can be especially demanding (Nosaka & Sakamoto, 2001).
For example, movements that challenge the hamstrings in a lengthened position, deep knee-flexion exercises for the quadriceps, or exercises that heavily load other muscles near their stretched positions may produce substantial soreness—particularly when someone is not accustomed to them.
This is one reason changing exercises can suddenly make you sore even when the new workout is not objectively “harder” than what you were doing previously.
Why Beginners Get So Sore
Anyone who remembers their first few weeks of resistance training probably remembers the soreness that came with it.
Beginners commonly experience substantial DOMS because almost everything they are doing is novel.
Their muscles have not yet adapted to repeated eccentric loading, unfamiliar ranges of motion, or the specific mechanical stresses associated with resistance training.
The same phenomenon can occur in experienced lifters when introducing a new exercise, returning from a long break, substantially increasing training volume, or training a muscle through a range of motion they are not accustomed to.
Fortunately, the body adapts remarkably quickly.
The Repeated-Bout Effect
One of the most important concepts for understanding soreness is the repeated-bout effect.
After being exposed to a particular exercise or type of eccentric loading, the muscle becomes substantially more resistant to damage from subsequent exposures. When the same or a similar workout is repeated, markers of muscle damage, strength loss, swelling, and soreness are generally reduced (McHugh, 2003).
Imagine performing Romanian deadlifts for the first time.
The first session might leave your hamstrings extremely sore for several days. After several weeks of consistently performing Romanian deadlifts, however, you may be using more weight and performing more repetitions while experiencing considerably less soreness.
It would make little sense to conclude that the first workout was therefore better.
In reality, your body has simply adapted to the stimulus.
This is why soreness tends to be particularly pronounced in beginners and why experienced trainees often experience relatively little soreness from exercises they perform consistently.
Does Soreness Mean You Stimulated the Target Muscle?
This is where soreness can provide some useful information.
If you perform an exercise intending to train a particular muscle and that muscle becomes sore afterward, it is reasonable to infer that the muscle experienced a meaningful training stimulus.
If you perform Romanian deadlifts and your hamstrings become sore, your hamstrings were clearly exposed to meaningful mechanical stress. If you perform chest presses and subsequently experience soreness in your pectorals, your chest was almost certainly involved substantially in the exercise.
In that sense, soreness can be indicative of a stimulus reaching the target muscle.
But this distinction is important:
Evidence that a muscle was stimulated is not evidence that it was stimulated optimally.
More soreness does not necessarily mean more hypertrophic stimulus.
More Soreness Does Not Mean More Muscle Growth
This is perhaps the biggest misconception surrounding DOMS.
Muscle damage and soreness often occur alongside resistance training, but the relationship between soreness and muscle hypertrophy is not straightforward.
Research examining different markers of exercise-induced muscle damage has found that the magnitude of soreness does not reliably correspond with the magnitude of muscle damage itself (Damas et al., 2016, 2018). Even more importantly, muscle damage does not appear to be necessary for muscle hypertrophy.
Resistance training can stimulate muscle growth with relatively little soreness, particularly once someone has adapted to their training program.
Conversely, it is possible to create enormous amounts of soreness without providing an especially productive hypertrophic stimulus.
Imagine performing hundreds of walking lunges after not doing them for six months. You might be incredibly sore for four days.
That does not necessarily mean you stimulated more muscle growth than you would have from a well-designed, progressive resistance-training session that produced relatively little soreness.
In fact, excessive muscle damage may temporarily interfere with training performance and muscle function (Damas et al., 2016, 2018).
The goal of resistance training should therefore not be to maximize soreness. It should be to provide an adequate stimulus that can be recovered from and progressively repeated.
No Soreness Does Not Mean Your Workout Was Ineffective
The opposite mistake is equally common.
Someone completes a workout, wakes up the next morning feeling completely normal, and thinks:
Maybe I didn't train hard enough.
But the absence of soreness tells us very little about whether a workout stimulated muscle growth.
If you are consistently performing an exercise, progressively increasing repetitions or load, training the target muscle through an appropriate range of motion, and taking your working sets sufficiently close to failure, there is little reason to deliberately modify your program simply because you stopped getting sore.
In fact, becoming less sore from the same type of training is exactly what we would expect as your body adapts.
This is one reason experienced lifters should be particularly careful about chasing soreness. Constantly changing exercises simply to create a novel sensation can generate soreness, but it can also make it harder to objectively track performance and progressive overload.
Soreness Is Not the Same Thing as Recovery
Another common assumption is that a sore muscle is automatically an unrecovered muscle.
There can certainly be overlap. Severe exercise-induced muscle damage can temporarily reduce strength, range of motion, and force-producing capacity (Peake et al., 2017; Damas et al., 2016, 2018).
However, soreness itself is not a perfect measure of these changes.
You can be mildly sore and perform extremely well. You can also feel relatively little soreness while still experiencing fatigue that negatively affects performance.
This is why soreness should be considered one piece of information rather than the sole measure of recovery.
A more useful question than:
“Am I still sore?”
may be:
“Can I perform normally?”
If you have mild soreness but can move through your normal range of motion, maintain your normal technique, and reproduce or improve your previous performance, the soreness itself may not be particularly concerning.
If soreness is severe enough that you have lost substantial range of motion, your strength is noticeably reduced, or you have to alter your technique to perform an exercise, additional recovery may be warranted.
Should You Train a Muscle That Is Still Sore?
Mild soreness does not automatically mean you need to avoid training that muscle.
The severity of the soreness and its effect on performance matter much more.
If your quadriceps are slightly sore but you can squat normally, produce similar force, and maintain your usual technique, there may be little reason to skip the workout solely because some soreness remains.
On the other hand, if your quadriceps are so sore that walking downstairs is difficult, your knee flexion is noticeably limited, and your squat technique changes because you are uncomfortable, forcing another hard session is probably not productive.
This distinction is useful because it shifts the focus from how you feel at rest toward what you are capable of doing.
When Soreness Becomes Counterproductive
Some soreness is a normal consequence of training.
Extreme soreness should not be the goal.
A workout that produces severe DOMS may impair force production, decrease range of motion, and negatively affect subsequent training sessions (Peake et al., 2017; Damas et al., 2016, 2018).
This creates an important cost-benefit question.
Suppose one leg workout makes you so sore that you cannot train your legs productively again for five days. A slightly less damaging workout might allow you to recover faster, perform better during your next session, and accumulate more high-quality training over the course of the week.
The second workout may ultimately be more productive despite causing less soreness.
This becomes especially relevant when considering training frequency. The goal is not to create the largest possible disruption during each individual workout. The goal is to create enough stimulus to promote adaptation while still allowing high-quality training to occur repeatedly over time.
What Should You Track Instead of Soreness?
Soreness can be noted, but it should sit relatively low on the list of metrics used to evaluate a resistance-training program.
More useful indicators include:
- Performance: Are you gradually lifting more weight or performing more repetitions?
- Proximity to failure: Are your working sets sufficiently challenging?
- Target-muscle involvement: Is the intended muscle meaningfully limiting performance?
- Technique and range of motion: Are you performing the exercise consistently enough to track progress?
- Training volume and frequency: Are you accumulating an appropriate amount of productive work?
- Recovery between sessions: Can you return and perform at a high level?
- Long-term progress: Are strength, muscularity, or other desired outcomes actually improving?
Soreness can supplement this information, but it should not replace it.
Practical Recommendations
You do not need to avoid soreness, and you do not need to chase it.
If you introduce a new exercise or return to training after time off, some soreness should be expected. Starting with slightly less volume and gradually increasing training demands can help limit excessive DOMS while your body adapts.
If you become sore in the target muscle after training, you can reasonably view that as evidence that the muscle experienced meaningful stress. But avoid interpreting the amount of soreness as a direct measurement of workout effectiveness.
Similarly, if an exercise stops making you sore after several weeks, that is not a reason by itself to replace it. The repeated-bout effect means reduced soreness is a normal consequence of adaptation.
Most importantly, evaluate recovery based on more than soreness alone. Consider your strength, movement quality, range of motion, and ability to perform your next workout.
The Bottom Line
Muscle soreness is a real physiological response to training, particularly after novel exercise, high-force eccentric loading, and exercises that heavily challenge muscles at longer lengths.
It can provide useful information. Becoming sore in a target muscle suggests that the muscle experienced meaningful stress from the workout.
But soreness is not a scorecard.
Being more sore does not necessarily mean you had a better workout, stimulated more muscle growth, or trained the target muscle more effectively. And being less sore does not mean your workout failed.
As you become accustomed to an exercise, the repeated-bout effect makes you increasingly resistant to muscle damage and soreness. You can therefore become stronger, lift heavier weights, perform more repetitions, and continue stimulating muscle growth while experiencing progressively less DOMS.
Rather than asking whether a workout made you sore, ask whether it provided a productive stimulus that you can recover from, repeat, and progressively improve.
That is ultimately a much better indicator of effective training.
References:
1. Cheung, K., Hume, P. A., & Maxwell, L. (2003). Delayed Onset Muscle Soreness: Treatment Strategies and Performance Factors. Sports Medicine, 33(2), 145-164. https://doi.org/10.2165/00007256-200333020-00005
2. Peake, J. M., Neubauer, O., Della Gatta, P. A., & Nosaka, K. (2017). Muscle damage and inflammation during recovery from exercise. Journal of Applied Physiology, 122(3), 559-570. https://doi.org/10.1152/japplphysiol.00971.2016
3. Proske, U., & Morgan, D. L. (2001). Muscle damage from eccentric exercise: mechanism, mechanical signs, adaptation and clinical applications. The Journal of Physiology, 537(2), 333-345. https://doi.org/10.1111/j.1469-7793.2001.00333.x
4. Nosaka, K., & Sakamoto, K. (2001). Effect of elbow joint angle on the magnitude of muscle damage to the elbow flexors. Medicine & Science in Sports & Exercise, 33(1), 22-29. https://doi.org/10.1097/00005768-200101000-00005
5. McHugh, M. P. (2003). Recent advances in the understanding of the repeated bout effect: the protective effect against muscle damage from a single bout of eccentric exercise. Scandinavian Journal of Medicine & Science in Sports, 13(2), 88-97. https://doi.org/10.1034/j.1600-0838.2003.02477.x
6. Damas, F., Phillips, S. M., Libardi, C. A., Vechin, F. C., Lixandrão, M. E., Jannig, P. R., Costa, L. A. R., Bacurau, A. V., Snijders, T., Parise, G., Tricoli, V., Roschel, H., & Ugrinowitsch, C. (2016). Resistance training-induced changes in integrated myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle damage. The Journal of Physiology, 594(18), 5209-5222. https://doi.org/10.1113/JP272472
7. Damas, F., Libardi, C. A., & Ugrinowitsch, C. (2018). The development of skeletal muscle hypertrophy through resistance training: the role of muscle damage and muscle protein synthesis. European Journal of Applied Physiology, 118(3), 485-500. https://doi.org/10.1007/s00421-017-3792-9