Two years ago, I started looking at strength training models for endurance athletes, from traditional models (low weight, high rep), to the popular (Crossfit), to the obscure and very difficult (Gym Jones). In 20 years of running, I’ve tried it all. As a sophomore in college, I took 22s off my mile PR, and avoided any strength training like the plague, thinking it would cause unnecessary weight gain. Then I entered the real world, and realized chicks don’t generally dig skinny dudes with large noggins, so I started lifting several times a week in addition to running. At some point in my triathlon days, as I started getting ready to go through 2 years of the hardest training the military has to offer, I did a lot of high-intensity ballistic calisthenics under Zane Castro’s guidance. Training for my first marathon, I experimented with a hypertrophic regimen designed by the notable John Berardi for NHL players. This was interesting because what I did was meant to build mass, strength, and power while I simultaneously put in a lot of mileage. I did Crossfit avidly in Tucson, and in the past couple of years have felt more a kinship with Gym Jones than any other school of thought. But the common thread through all this? Endurance. Strength was never the point per se; it was what strength could do for me as an endurance athlete. Yeah, once in a while I might get a little testosterone-y and obsess over my bench press max, but for the most part, I’ve never cared much about strength except for what endurance it has enabled:

– 2:04 PR for Olympic distance triathlon
– 1:19 PR for half marathon
– 2:48 PR for marathon
– Crush Phase 2 and Indoc

Not that these are world-class numbers, but they represent accomplishments for me. However, as much as I’ve studied the art and science of endurance over the years, I’ve given strength very little of that. It’s always been “catch as catch can” for me; a casserole of exercises and approaches, mostly made up as I find myself in the miasmic kitchen of steel and rubber known as the weight room. Coming into this series, my approach changed not at all: talk about my opinion on strength and talk about how I get after it. In fact, as I was writing Foundations, I found myself penning a line on the lack of scientific research regarding strength and endurance. As I looked at that sentence, I realized what a poser I would be if I said that. The extent of my research consisted of what I’d read in Running Times and maybe a website or two; surely there had to be some studies out there with something to contribute.

Thanks to Google Scholar, it turns out I was right. There is a boatload of info out there. And what shocked me is how very little of it makes its way into the running literature. In fact, none of the five studies I read, the oldest of which is 13 years old, have I seen in a coaching book, article, or really, even talked about by runners and their coaches. And folks, I am around a lot of endurance athletes. But then again, by my observations, runners are relative Luddites in comparison with our cycling, and triathlete cousins, whom I find much more open to advancements in technology and training methodology. Anyway, five studies, right? I’m just scratching the surface obviously, but you can check out the links for yourself below.

The first one I looked at, titled “Explosive-strength training improves 5-km running time by improving running economy and muscle power” from the Journal of Applied Physiology, can be found here in its entirety. It was the least eye-opening of the studies, but still telling. The study took two test groups of “well-trained” runners, whose average 5k time coming into the experiment was around 18:00-18:30, and the athletes were running 500+ hours a year (10+ hrs a week). The test group replaced 32% of their run training with strength over a period of 9 weeks while the control group replaced only 3% of their run training. Run training for both groups was identical save the variations in strength. The strength training was largely explosive strength work: sprints, jump work (what I will refer to in the future as “ballistic calisthenics”), and low-load/high velocity leg strength exercises, and both groups did traditional circuit work. The results? The test group’s 5k time decreased around what 30-45s on average, while the control group actually got slower. What was even more interesting is that traditional fitness markers, to include VO2 Max and Lactate Threshold remained virtually the same in both groups. Also important to note: weight gain was virtually non-existent in the test group. There’s a lot of fancy science-talk in the study, but the researchers were forced to the conclusion that the increase in performance was due to neuromuscular adaptation, which led to improved running economy and velocity at maximal anaerobic threshold. That last bit translates to exactly how fast they could sprint over a series of 20s efforts.

Next, I checked out “Effects of strength training on endurance capacity in top level endurance athletes” from the Scandinavian Journal of Medicine & Science in Sports. For this one, I had to call in the first of several favors from a friend with academic access to online journal articles, since all you can get at the link is the abstract. This one was a little different from the others, in that it tested true elite athletes, albeit cyclists, from the Danish National Cycling Team. You multisport athletes will want to pay attention to this study in particular. The VO2 Max numbers associated with these cats was impressive: 71-75 mL Os/min/kg. Translating this to average runner-speak, these guys were the cycling equivalent of runners just under world-class. For example, Steve Prefontaine clocked in at around 84, so if these guys were runners, they’d be national class. But, as we saw in the last study, impressive VO2 max numbers don’t necessarily translate to better times. I personally have tested out somewhere around 71, if I recall correctly from the last time I tested, in 2005; but as you know, I’m not pulling in shoe endorsements the last time I checked. Anyway, for this study, the test group did 16 weeks of strength, while the control group did no strength work. Both groups performed the same endurance training. Once again, the strength group came out on top, boosting power output over a 45 minute max effort test by a whopping 8%. That doesn’t sound like much until you realize these guys were putting out about 315 watts of power, and improved to almost 350 watts. For you cycling geeks, you know that’s a huge gain in just four months of training. They more than doubled the improvement of their unlucky control-group cousins. Unlike the last study, this one involved what they call “high-load” strength work, which translates to loads > 85% of one-rep max. And a long period: four months. What does that mean? These guys were performing lifts with an amount of weight that precluded them from doing more than 4-6 repetitions. What’s crazy about all this? No hypertrophic adaption. Once again, no weight gain. This is where the research started to blow my paradigm out of the water. I’ve always learned that heavy lifts lead to weight gain. Sound familiar? It should. Just about every running book that addresses strength sticks to the old low-weight, high-rep routine. But this study unravels that old BS: gains associated with strength work have to involve heavy, heavy loads, low reps, and a high volume of work (four months at the least).

“Maximal Strength Training Improves Running Economy in Distance Runners,” from Medicine & Science in Sports & Exercise (found in its entirety here), really sealed the deal for me. This study tested seventeen male and female athletes with 5k times ranging from 18:40-19:00ish.VO2 Max and weight was once again tested before and after for both the test and control groups. This time, the control group did eight weeks of what the researchers called “Max Strength Training,” or “MST.” MST included the following: 4 x 4 Half Squat, 3:00 rest between sets, and they did it 3x/week for eight weeks. I found a good video of a half squat, where the athlete only completes about 90 degrees of motion.

I have a feeling they only went with the half-squat because runners typically have terrible mobility, most notably in the hips, which are crucial for full range-of-motion squats. When the athletes were capable of doing five reps, more weight was added to drop it back to four. Running training continued as per the norm for both groups, but the researchers controlled the training less, choosing instead to simply record data relative to the training. The end results: the test group increased their half-squat max, how quickly they generated force during the movement, running economy (RE), and time to exhaustion at maximal aerobic speed, all with no change in weight or VO2 Max numbers. Boom. Those last two are the areas most important to us as endurance athletes because once again, who cares how much steel you can crush unless it relates to your pursuit? This time, 5km times were not recorded as fitness markers, since the researchers wanted to focus on the finer details. And once again, the conclusion inferred neuromuscular adaptation was related to the improvements.

Ladies, feeling a little left out? “Strength Training in Female Distance Runners: Impact on Running Economy,” courtesy of the Journal of Strength and Conditioning Research, should scratch that itch. An older (1997) and far less rigorous study, the researchers found a 3-4% gain in running economy after 10 weeks of strength. However, what’s interesting from this study is that they went with a hybrid approach of old and new. Calf raises and abdominal exercises were high-rep, ranging from 10-20 reps all the way to max number of reps. However, quad and hamstring curls were 8RM, and squats were 6RM. In the end, the test group’s 3-4% increase in RE is only 50% of what MST produced in the previous study. Interesting, huh?

Finally, I dug up “Does Core Strength Training Influence Running Kinetics, Lower Extremity Stability, and 5000m Performance in Runners?” A 2009 Journal of Strength and Conditioning Research article, it correlated a 45s improvement in 5k time in what I would call recreational runners. Strength in this case was limited to core work utilizing typical Swiss Ball exercises. However, runners did not generate additional force during the foot strike portion of the stride, which makes sense to me. Most of our force generated while running is derived from primarily leg motion, then arm motion. These subjects especially (5k times close to 30:00) were not running at velocities where arm swing is closely correlated to run speed. Additionally, the researchers used the Star Excursion Balance Test (SEBT) to test dynamic flexibility, or the ability to stay balanced while in motion. While both the test and control groups improved over six weeks, the test group doubled the control group’s progress. The SEBT:

The SEBT is a pretty common rehab exercise for leg injuries, and great tool for measuring your proprioreceptive abilities. But again, the core work was exactly that – core work. Core stability is but one aspect of the SEBT, and largely limited to balance. I would not expect to see a strong correlation between just core strength and dynamic flexibility, which takes into account joint mobility and your established proprioreceptive capabilities.

I’ll be honest; reading these studies, as illuminating as they’ve been, I have a lot of questions. Studies are closely controlled, and occur in the sanitized world of lab coats and stainless steel instrumentation. Out here in the real world, things get messy. What kind of endurance training methodology was employed during the strength studies? Did anyone account for body-typing in the evaluation of hypertrophy or did all the studies simply focus on your typical endomorphic, rail-thin endurance athlete? What about periodization and interaction of strength with varying phases of endurance training?

However, despite these questions, I think I’ve found enough to change how I approach strength as it relates to endurance. If we’re looking for gains, strength certainly won’t hurt so long as there isn’t any weight gain involved. And it appears that in order to get the most bang for the buck, we should be lifting a lot heavier than we have been. Consulting with Zane, he’s been reaching some of the same conclusions through his own research. In fact, he shared with me the remarkable story of one of his elite triathletes. A former Div III trackster, she never PR’d for the 10k in four years of running. Then Zane got a hold of her, and through focused mobility and MST, she’s now running 10ks a full two minutes faster. Oh, and she’s doing it after a 1500m swim and 40k bike as an Olympic-distance elite triathlete.

Whew! 2200 words in, and I feel like I could keep rolling. But I won’t. Stay tuned for the next installment, as I’m going to boil all this down and approximate what I think strength approaches need to look like for the endurance athlete.