Why Heavy Strength Training is Most Effective for Runners

By Jason Koop,
Head Coach of CTS Ultrarunning

Earlier this year as the pandemic locked down athletes around the world, CTS released our entire DVD workout library for free. The contents were a treasure trove of indoor cycling, strength training and stretching workouts, all produced well over a decade ago, far before athleisure was invented and smack in the middle of the khaki era.  To my surprise and horror, a 15 year old gem starring yours truly was also cast into the wild, ‘Core Strength for Cyclists and Triathletes’. This came as a surprise, as I’ve spent the last several years in an Indiana Jones-type pursuit trying to track down any remaining copies so I can destroy the media and responsibly recycle the remaining plastic contents.

Rethinking my earlier fashion choices aside, the content release gave me a chance to pause and reflect on the actual prescription of the workout. Was the workout any good and would I do anything different a decade and a half later? While the workout itself can stand the test of time, the short answer is I certainly would change a lot about that prescription and the way it was presented. I’m not coaching the same as I was last year, or the year before that or the decade before that. New information is coming out all the time and strength training is certainly an aspect we continue to learn more and more about.

So, what’s changed in strength training?

A research paper recently published in the European Journal of Sports Science sought to tease out the difference in efficacy of three markedly different strength training programs. The research team took forty two runners and divided them into one of three strength training groups: a heavy strength training group (HST), a complex strength training (CPX) group and endurance strength training (EST) group and had them complete twice weekly strength training sessions in addition to their normal run training, for 6 weeks. The aim of the study was to compare and contrast the different strength training styles to see which intervention could elicit certain adaptations. The subjects were studied for strength variables (maximum isokinetic eccentric and concentric strength), power variables (squat jump and counter movement jump) and run performance surrogates (vVO2_max, the velocity you can run at VO_2max and running economy).

Central to the design were the strength training interventions. All three groups were matched for overall training load. Meaning, that no one strength training intervention was longer or harder than the other. This is important because with any real-life training intervention, there is only so much time and effort to go around. You can usually get superior results when any type of training load is increased (think of simply adding running time or adding strength training to whatever you are doing now; you are going to get better). On the other hand, when you compare one intervention to another in a load matched setting, you get to find out exactly how much better equivalent training interventions truly are. In addition to this load matching, all groups did the exact same types of exercises: a back squat, a split squat and a walking lunge, just different set and rep combinations and in the case of the CXT group, adding in a complex pair.

In this setup, a ‘complex pair’ refers to strength training design where a traditional strength training exercise is ‘paired’ with a more powerful plyometric exercise in the same movement pattern. The back squat was paired with a drop jump (literally jumping off of a 30 cm platform), the split squat was paired with a single leg hop and the walking lunge was paired to a double leg hurdle hop. To complete the complex pair, you would do a set of the traditional exercise (five reps in this case) followed by a set of the plyometric-type exercise (once again, five reps). The theory is that by pairing traditional strength workouts with its quicker and more explosive counterpart, better neuromuscular and force generating capabilities of muscles and motor units can be achieved.

Back to the overall load matching. The HST group did 5 sets of 5 reps of the exercises at 70-85% of their one rep maximum. The CPX group did 3 sets of 5 reps (as they had more overall exercises due to the complex pairing). The EST group did 5 sets of 10-20 at very light weights, 30-40% of their maximum. A complete view of the three different strength training interventions can be seen in the table below.

*adapted from Fi et al. (2020), Table 2

My guess is that for many of you out there, strength training falls into the last category, utilizing a low weight, high rep approach. You do bodyweight squats or maybe even a timed leg lunge circuit accumulating up to 20 reps (or maybe even more) in a single set for any particular exercise. For whatever reason this high rep, low weight style of strength training gained a lot of traction in running circles in the 90s and early 2000s and that style of strength training programming still exists today. In any case, the research team did a good job in ensuring that each style of strength training was no more time consuming or taxing than the other. You could incorporate any one of these sessions with no differences in the alteration of run training prescription stemming from the difficulty of the session.

The participants kept up a similar run training program between each of the groups, running about 30 miles per week at mainly a low intensity, with some higher-intensity sessions sprinkled into the mix. So, now you have three different interventions that all consume the same amount of time and effort, while at the same time the underlying run training was also matched. It’s a great compare and contrast setting to illuminate the efficacy of these different strength training styles. So, which one wins?

And the winner is…

HST and CPX produced similar improvements in maximum strength, power (as ascertained through the squat jump and countermovement jump) running economy and vV02_max. Additionally, HST and CPX resulted in greater eccentric strength and running economy improvements than the low weight, high repetition EST, which showed some marginal and not significant improvement. This adds to the body of literature that overall favors heavy and/or plyometric strength training being superior to low weight, high repetition strength training specifically for running (and in many cases other types of endurance) performance.

In addition to this, one of the interesting ways the research team standardized the groups was that all of them abstained from strength training for the prior 6 months before the intervention. Normally when this is the case, any intervention results in a meaningful positive adaptation simply because the training stimulus is novel as well as an overall increase in training load (you are adding strength training on top of your normal run training). So, when you look at the fact that the EST (low weight, high rep) produced basically no response despite the intervention being additive to the underlying run training load and despite it being novel, you could easily say that it was a waste of the athlete’s time. And I wouldn’t argue with you.

All too often, runners are trying to shoehorn strength training into their training programs and at the same time avoiding in every way possible to make that strength training remotely difficult. We see this in lunge matrixes, timed bodyweight squats, convenience-oriented circuits consisting of only a few minutes’ worth of work, and related to my first example, shades of programming from ‘Core Strength for Cyclists and Triathletes’ which was a predominately bodyweight-based program. All of these examples suffer from the same error: they are too easy to be meaningful to your performance. Are they better than nothing? Maybe, but I think it’s a stretch. Most important, as the literature is starting to demonstrate more and more, you are better off taking that time you are spending doing a billion bodyweight step-ups and redirecting it into a handful of heavy squats. Meaning, if you only have a handful of minutes to spare a few times a week for strength training, pick the style that is going to provide the best bang for your buck. And that’s exactly what these load matched studies are great at!

For further exploration

I realize that the topic of optimizing strength training, much like endurance training, is complex and nuanced. It is far more multifaceted than one research study comparing 6 weeks’ worth of training intervention. For athletes I work with who also strength train (and that is some, but not all of them), we periodize their approach much like their run training. In this way, there are periods of high rep/low weight, high power, and low rep/heavy weight training that are scheduled throughout the year. For more context on this subject, I recorded two sperate podcasts on this with one of our coaches, Sarah Scozzaro here and here. Sarah earned her M.S. in Exercise Science with a concentration in Performance Enhancement and Injury Prevention as well as certifications in personal training and Restorative Exercise, and she was consultant with an NFL team for four seasons on restorative work, injury prevention and performance enhancement.