What are the implications of diminishing levels of soreness in Delayed Onset Muscle Soreness (DOMS)?

Question

A while back, I sent out the following query to a subject matter expert (through a different social media platform), but did not receive a reply. Thought I'd post it here to see if anyone with expertise on Delayed Onset Muscle Soreness (DOMS) can answer it. What I wrote earlier follows:

Lately, I’ve been unable to produce DOMS from my weightlifting sessions. I’ve always thought that if I’m not sore the next day, I wasted my time at the gym. Now I know some believe that you don’t have to experience DOMS for muscle growth, but where is the science on that theory? Regardless, some of my theories as to why I’m not experiencing DOMS are listed below:

1. I’ve reached some sort of pre-determined genetic threshold in how much I can tear my muscles.

2. The effects of weightlifting diminish once you go past a certain chronological age (e.g., 20s vs. 30s vs. 40s and upward).

3. I tend to include some amount of cardio during my weightlifting sessions, perhaps flushing out any lactic acid built up during the weightlifting (but I’ve read that lactic acid build-up isn’t what causes DOMS).

4. I’m not currently taking a multi-vitamin. Right now I take in a fair amount of Vitamin C on a regular basis, but no multi-vitamin. Before a workout, I’ll take vitamin C and selenium. I’m also taking a new brand of iodine called Tri-Iodine by Terry Naturally (albeit sporadically). It contains 3 forms of iodine – potassium iodide, sodium iodide, and molecular iodine.

5. I consume far less sugar than I did in 2012. In 2012, my sugar averaged 83 grams/day; in 2013, it was 75 grams. My goal is to get it lower than that in 2014. (It averaged 63 g/day in 2014.) What’s the relationship between sugar in the diet, inflammation, DOMS, and the ability to grow muscle?

Having said all that, I took a couple of long breaks from my typical workouts while focusing on other projects/activities and have recently begun exercising on a regular basis again. The first break was a period of five weeks and even after that long break, I felt as if I had retained a significant amount of strength despite the break. DOMS produced from workouts was present but not intense. The exercise phase that followed the five-week break was 14 weeks in duration followed by a rest period of 13 weeks. After this last break of 13 weeks, I am now exercising regularly again. I feel significant strength has been lost and DOMS is easily attained from far more simple and less grueling workouts.

My conclusion from all of this is that, genetically, we all have a peak and as we approach that peak, we are less and less likely to feel the effects of DOMS. Without steroids, a person's muscle growth has a limit and additional amounts of exercise either through load or volume will have increasingly diminishing effects. I don't think this conclusion is much of a revelation, but I would be interested in knowing if any of the aspects I have suggested have an impact on DOMS and whether or not researchers have conducted any studies on these aspects as they relate to DOMS.

Answer 1

I've written a previous answer about this, which I would recommend reviewing.

In short, DOMS is not a good indicator of muscle stress, growth, recovery, or training effectiveness. It is brought about through a combination of factors, primarily eccentric exercises. From Wikipedia:

Muscles undergoing heavy eccentric loading suffer greater damage when overloaded (such as during muscle building or strength training exercise) as compared to concentric loading. When eccentric contractions are used in weight training, they are normally called negatives. During a concentric contraction, muscle fibers slide across each other, pulling the Z-lines together. During an eccentric contraction, the filaments slide past each other the opposite way, though the actual movement of the myosin heads during an eccentric contraction is not known. Exercise featuring a heavy eccentric load can actually support a greater weight (muscles are approximately 40% stronger during eccentric contractions than during concentric contractions) and also results in greater muscular damage and delayed onset muscle soreness one to two days after training.

The problem is that people conflate "damage", "soreness", and "effectiveness of training", all which are different and loosely related at best.

This is easily identified that if eccentric exercises were the most effective ways to train, world class athletes would just do eccentric exercises all day long or at least prioritize them highly.

However, decades of fierce competition and scientifically analyzed training programs focus on concentric movements. Eccentric movements are relegated to adjusting to heavier weights that one can't do concentrically (like a negative pullup until a proper concentric can be completed), or good mornings, where the negative is required to not get injured.