Why Strength Training Won’t Make You a Faster Ultramarathon Runner

By Jason Koop,
Head Coach of CTS Ultrarunning

Last week, I wrote a teaser article overviewing the most controversial topics in ultramarathon training. If you want a refresher (and the Cliff’s notes version of this blog) go check it out here. This week, I will tackle why you should (or should not) strength train as part of your ultramarathon routine.

Strength training is a big umbrella

One of the confounding aspects of discussing strength training is the oversimplification of the term ‘strength training’. Way back in the day when all you had in a gym was iron, iron to hold up all the iron, and athletes lifting the iron in ridiculous quantities, an athlete’s goal was simply to lift more weight and thus improve their strength. In this sense, athletes were classically training for (improved) strength, and thus the term ‘strength training’ was coined. Nowadays, ‘strength training’ has come to mean any exercise done, with or without weights, in any set and rep combination. This can be done with copious amount of iron, body weight, various machines and other contraptions, and even brightly colored tubes and bands.

The fact that all of these different combinations are still considered ‘strength training’ does not do anyone any favors. While almost any of the aforementioned workouts will improve strength, some will be more focused on coordination, stability, balance, and a host of other outcomes. In my humble opinion, to lump planks in with plyometrics with the same overarching title is a disservice to athletes. But I digress.

To strike a balance between accuracy and simplification, I will present ‘strength training’ in two primary contexts for an ultrarunner based on their chief performance outcome: strength training to improve running economy, and strength training to prevent injuries.

Strength training for Improved Running Economy 

Running economy (defined as the amount of oxygen you consume at a given pace) has long been lauded as one of the key performance metrics for endurance running (the other variables being VO₂max and the percent of VO₂max you can sustain). Simply put, if you utilize less oxygen at a given speed, that speed is more sustainable. A host of variables contribute to running economy, including body weight, shoe weight and properties (Nike Vaporfly, anyone?), fuel utilization, and muscular and tendon stiffness. Strength training, particularly when lifting heavy or explosively, has long been shown to improve running economy by about 2-4%.

How strength training improves Running Economy

Before you jump right into a strength training routine to improve your running economy, it is important to understand how strength training can improve running economy, how we measure it, and what the applications are in an ultrarunning setting.

Biomechanists refer to runners as a ‘spring mass system’ where your legs are springs and your body is a mass propelled by those springs. As we all realize, part of the energy you need to run is provided by active muscular contraction. But, part of the energy needed to run is essentially free. As your muscles and tendons are stretched during the gait cycle, they harness elastic energy (like a rubber band when stretched) and return this energy, free of metabolic charge to the user. Strength training improves running economy primarily by improving the elastic energy return of your muscles and tendons. Think of your muscles and tendons becoming stronger, thicker rubber bands that snap back harder and faster when stretched. Strength training may also improve how effectively you push against the ground to propel yourself forward by better coordinating your neuromuscular system.

In the lab, the way we measure this is to put a runner at a given speed on a treadmill and measure the rate of oxygen consumed. The lower the rate of oxygen consumption, the better the runner’s economy and theoretically the better the runner will perform across a variety of distances. The chosen speed is difficult, but below a runner’s lactate threshold so that the runner is at a steady state of oxygen consumption. The speed used to study Running Economy is important, as it is only moderately hard (typically 70-80% of VO₂max, an intensity one could hold for 2 or 3 hours) but far harder than an ultramarathon, in most studies, and in most ultrarunning cases.

How and why would you strength train to improve Running Economy

Strength training to improve running economy has to be hard. Think lifting heavy weights for few repetitions (for example, 5 sets of 5 squats, done almost to failure), doing plyometric exercises (either with bodyweight or weights), or Olympic style lifts. Strength training in this context should be done 2-3 times per week and maintained throughout the course of a season. This type of lifting improves the spring stiffness of your legs, gives you a boost of free energy, and therefore reduces the amount of oxygen you need at a given speed (or at least the speed tested in the laboratory).

My take on strength training to improve running economy for Ultrarunners

Despite all of the seemingly positive reasons to incorporate strength training as a means in order to improve running economy, I rarely incorporate it for ultrarunners (bring out the rotten tomatoes and eggs and give them a whirl in my direction). Before you roll your eyes too hard, follow along with the rationales below.

Strength training to improve running economy is hard

In order to get much out of your time in the gym, you are going to have to push yourself (once again, heavy weights, explosive work or plyometric work). Your body can only handle so much stress. And, if you add in stress from jumping around and pushing up heavy weights, you will have to take some stress away somewhere else, namely in the form of lower running volume, less intensity and/or reduced frequency of training. So, you’re literally trading one adaptation for another (the adaptation you get from running more vs. what you get in the weight room). While some studies will point out that this tradeoff is worth it, I find that from a practical standpoint, the reduction in run volume/intensity/frequency is not worth it.

To illustrate my point, I always use an example of how to properly incorporate a strength training routine within a week of training. In most cases when we choose to utilize a strength training program with an athlete, we incorporate the lifting session on the evening after a hard workout. This prioritizes the run work over the lifting by giving as much space as possible until the next hard workout. For example, if you have two hard workouts during the week, you would do one of them on Tuesday morning, lift Tuesday evening and then do the second hard running workout on Friday with the lifting session that same evening. In this sense, strength training is shoehorned into the program to interfere as little as possible with the more meaningful run work.

I’m not convinced that the improvements in running economy are meaningful in an ultramarathon setting

I have serious doubts that much elastic energy return will show up at the relatively slow speeds maintained during ultrarunning competitions. Ultrarunning is done at speeds far below where most running economy studies are done, and even slower than where most training occurs. And during walking (affectionally referred to as power hiking) or downhill running (where all the free energy is given by gravity). I fully admit that this is not thoroughly researched, but my stance is a ‘makes sense’ rationale based on the biomechanics involved and the intensity necessary during an ultramarathon.

Furthermore, ultrarunners compete at a relatively low aerobic intensity, far below the intensities used in most running economy studies. An improvement of ~2% in running economy when you are only running at 50-70% of your VO₂max (typical for most ultrarunning scenarios) simply is not that meaningful because the intensity is more than sustainable in the first place. In other words, improving your running economy such that you are running at 54% of your VO₂max vs 56% of your VO₂max really does not mean that much. Add to that the fact that just the simple act of run training (particularly at high intensities) improves running economy, and the argument to improve running economy with strength training tends to break down further.

Strength training for reduced injury risk

Strength training to reduce injury risk can come in two different flavors: the hard lifting mentioned above, and what I call ‘strength training in a physical therapy setting’. With the former, strength training reduces injury risk by literally strengthening the muscles, tendons and ligaments, thus making them more resilient to the day-to-day pounding all runners experience.

Strength training in a physical therapy setting is a completely different setup. Strength training in a physical therapy setting consists of small, controlled, and very specific movements to address specific strengths and weaknesses. Exercises like clamshells, controlled squats (perhaps on an unstable surface like a dyna disc or bosu ball), and monster walks are common. The relative physical costs of these exercises are low (i.e. they are easy or at least not hard) and they can be done 2-5 times per week.

My take on ultrarunners using strength training to reduce injury risk

As with the research that strength training improves running economy, strength training to mitigate injury risk is compelling. If you simply take this well done meta-study (citation TKTK), athletes who strength train experience a 43% reduction in injury risk. That’s a meaningful amount. If there were a magic potion that reduced injury by this amount, I’d have all of my athletes take it. But training has no magic shortcuts.

There is, however, another solution to mitigate injury. One that is far more effective, takes no additional time, requires no equipment or training and is actually an ergogenic aid. That solution is rest. Athletes who rest fewer than two days per week have over a 5-fold risk of an overuse injury. That is massive compared to a 43% reduction in injury risk with a strength training program. While taking two days off is not in everyone’s training program, my point is that in terms of effectiveness for reducing injury, rest is the sharper knife.

Here is the lynchpin in my argument: Adding strength training is antithetical to resting. The heavy and explosive strength training needed to reinforce muscles, tendons, ligaments and bony tissue is not rest. You’d be surprised how many athletes think of their lifting days as ‘rest days’ simply because they are not running. They are not rest days. Lifting is work. And, when comparing the relative injury risk-mitigating strategies, it is clear to me that resting is the more effective solution.

I will leave some room for ‘strength training in a physical therapy setting’ to be effective and done at a relatively low energy cost. While not rest, when done correctly these types of exercises can be simple, easy, and extremely targeted toward identified weaknesses a runner might have. Before you go and buy a set of exercise bands, see a qualified physical therapist and get some guidance.

Why else might ultrarunners want to strength train?

There are a wealth of other reasons you might want to strength train. Strength training for overall health, increased bone density, and specific functional purposes like picking your kids up, making you feel good, and enjoying the community are all valid reasons for tossing up some iron. Though not frequently, I do have my athletes strength train. I also personally hit the gym during certain periods. It’s OK as long as you are realistic about what you can and cannot accomplish, and you are clear about your goals. Before I have my athletes hit the gym, I check the following boxes:

• What are your goals for strength training? If it’s performance out on the trails, the program goes through a whole lot more scrutiny. If it’s one of the other goals mentioned above, that’s great! Just realize it does come at a compromise (which could be large or small).
• Are you already getting enough rest? If so, great! Reduce some run volume and then add strength training. If not, then rest will make a bigger impact and will need to be prioritized before initiating a strength training program.
• Do it right. Get some professional instruction, particularly if you want to lift heavy or explosively.