Is DOMS caused by lactic acid or lactate accumulation?
Nope. Lactate and other similar metabolic products that accumulate during exercise are efficiently cleared away by the body and back to normal levels within half an hour to an hour after completing your workout.
So what does cause DOMS?
There actually isn’t a for-sure answer for this yet(!), but the culprit may be (or partially be) micro-tears in your muscles and the surrounding connective tissue, particularly from the eccentric part of your training or activity. And the delayed soreness may be due to your nerves responding to the healing process. In other words, it’s quite possible that the pain you feel is caused by the repairs taking place, repairs that will hopefully help you not experience DOMS quite so severely from the same activity next time.
For a climber like me who has long struggled with the bigger muscles more than the forearm/fingers part of the equation, this makes sense, seeing as I am constantly fighting to keep bending my arms and locking off, meaning I am frequently – albeit unintentionally and much to my frustration – lowering myself away from holds even as I strive to resist this motion. All too often, my hands can still hang on but the muscles in my arms fail to stay appropriately engaged to do the next move. I’ve also heard that DOMS tends to be more pronounced in the upper-body muscles than the lower-body muscles, which also gels with my personal DOMS experience.
However, just like many other theories (both sport-science relevant and not), just because this makes sense doesn’t mean it’s necessarily the case – or that it accounts for the entirety of the DOMS phenomenon. DOMS may also have metabolic components and neurological components. The bottom line is that DOMS appears to be complex, and its exact cause(s) have yet to be clearly unraveled. For a more complete discussion on this, check out Paul Ingraham’s excellent article “Delayed Onset Muscle Soreness (DOMS): The biological mysteries of ‘muscle fever,’ nature’s little tax on exercise” on PainScience.com.
Does DOMS only happen to unfit people or people doing unfamiliar workouts?
Nope. It’s true, though, that being out of shape OR engaging in a novel workout/training stimulus/climbing experience (or both!) does seem to tip the scales in favor of increasing your likelihood to experience DOMS. And that with more regular participation in whatever the activity is that made you sore, you are less likely to experience DOMS post-workout – especially if you keep it at the same level (i.e. you don’t increase the volume, intensity, or frequency of your workouts). However, regardless of training status, people’s experience of DOMS varies, meaning that a total beginner might only get vague DOMS, while an experienced rock climber might routinely struggle with DOMS. Genetic predisposition almost certainly contributes to this aspect of DOMS.
Up Next Week: Climbing & Training Myths & Misconceptions 2: Delayed Onset Muscle Soreness (DOMS) (IYC Series), Part 2
This multipart series of articles starts here, in case you have to catch up – you’ll also find a full table of contents, complete with links, in that entry. This information and advice is based on my 20+ years of climbing along with observations I’ve made as a climbing coach/certified personal trainer. You might not agree with me or my take on things. That’s fine – feel free to take it or leave it as you wish! Also, remember that the information I provide here is purely offered as advice and that no exercises or training program should be undertaken without receiving medical clearance from a healthcare professional.
One other caveat: As will be true for all of the entries and articles in this series, if you’ve already mastered or maxed out the topic at hand to the best of your ability level, you’ll reap far fewer benefits or none at all from my suggestions – good for you that you figured it out, but sorry I couldn’t help you out more. Happy climbing and training!