12 May 2020
Why are high intensities “better” for strength?
PART 1: Framework for Discussion Brian Minor, MS, CSCS It doesn’t take a bunch of research to convince people that maximal strength outcomes tend to favor high(er) intensity loading. Not only do decades worth of anecdotes from both coaches and athletes support this message, robust meta analytic data illustrates the benefits of high(er) intensities on…
PART 1: Framework for Discussion
Brian Minor, MS, CSCS
It doesn’t take a bunch of research to convince people that maximal strength outcomes tend to favor high(er) intensity loading. Not only do decades worth of anecdotes from both coaches and athletes support this message, robust meta analytic data illustrates the benefits of high(er) intensities on strength outcomes (4), especially as an individual’s training experience advances (1,3).
What is less commonly discussed, is why this is the case? What is it about higher intensities that makes their inclusion so beneficial for strength development?
The most common responses are generally related to “specificity”, and how “strength is a skill”. In the case that an individual has a deeper understanding of exercise science, they may even go so far as to say that “heavy loads train your nervous system better”, as neural output plays a key role in maximal strength.
While these statements certainly all have merit, they are merely ways to bundle a number of variables and contributory factors for strength development together, as a means to simplify the discussion. This certainly helps us conceptualize the process though, no doubt about it. However, I believe there is substantial benefit in having a broader understanding of the mechanisms underlying strength development, specifically (pun intended) those influenced heavily by intensity. Such an understanding can not only indirectly help shape our training strategies and enhance our chances of making gains, it’s all actually pretty cool!
This is Part 1 of a 4 part series that will be unpacking some of the primary reasons why high intensities are generally more beneficial for developing maximal strength, and what we can learn from this understanding in the quest for PRs (or PBs for you Aussies).
In an effort to stay organized, we will discuss things in the following order:
- What are the primary influential variables in strength development?
- How do these variables enhance strength? (mechanisms)
- How do higher intensities influence these variables?
- How can we apply this information?
Some of these topics could very easily get deep in the weeds, arguably well beyond their utility to the discussion, so my aim is to keep this applicable and something the average gym bro can conceptualize and ultimately integrate.
What influences strength?
Most people tend to view strength through a wide lense, and often in a binary manner; muscular size increases one’s potential for strength, with increases in nervous system ‘drive’ allowing one to further express their strength potential. Although this is quite a reductionist view, this framework alone allows most coaches and athletes to begin to understand the utility and theoretical underpinnings of strength outcomes, including topics such as periodization, and areas of relative emphasis based on training experience (more on both of these later). These are valuable takeaways indeed, as research supports the idea that periodized programs lead to greater strength outcomes than non-periodized training (2,5), with the impact of periodization structure increasing with training experience (5). In practice, many powerlifters program mesocycles aimed to increase muscular development and work capacity, followed by periods of time pushing higher degrees of specificity both in terms exercise selection and heavier loads in a bid to ‘neurally’ capitalize on the increased force producing potential that comes with increases in contractile tissue. This is all in an effort to express their strength to the highest degree possible on meet day.
While the binary model is still useful, a more thorough categorization and expansion of strength training adaptations may best be categorized as either morphological or neurological in nature. A 2007 review by Folland and Williams (7) does an amazing job breaking down a comprehensive list of morphological and neurological adaptations to strength training. My original plan when I set out to write this article series was to closely examine them all, but I quickly realized such a deep dive into this research would extend this series well beyond what could be practically applied.
So, I am consolidating to those which are especially impactful for expressing maximal strength. These include:
- Changes in muscle size (hypertrophy)
- Tendon and connective tissue adaptations
- Increase in agonist activation
Parts 2 and 3 will discuss the morphological and neurological adaptations in more detail, and if/how intensity impacts their expression. Part 4 will provide some practical recommendations and food for thought (which I think is the most fun).
Lastly, in full disclosure, one of the reasons I chose to write about this topic was to get an opportunity to further unpack some of the more nuanced aspects of these topics myself. Writing has always been a useful process in accomplishing that. While I would consider myself proficient in my ability to read and interpret research, I can’t overstate how beneficial both the MASS research review and Chris Beardsley’s work helped me navigate these topics and steer me to some of the relevant research. I highly recommend both resources!
See you in Part 2!
4. Schoenfeld, B, Grgic, J, Ogborn, D, and Krieger, J. Strength and hypertrophy adaptations between low- versus high-load resistance training: A systematic review and meta-analysis. J Strength Cond Res , 2017.