When I was in grad school I was at the peak of my triathlon-obsessed days, and it always saddened me that I had to dig so deep for peer-reviewed research specific to triathlon, ultra, and other endurance sports. It was there, but sparse and nowhere near as relevant as research surrounding traditional sports—football, baseball, etc, and strength training.

Fast forward to now, and it’s refreshing to see multiple studies coming out on triathlon, ultra and other “more obscure” endurance sports topics. In particular, The Journal of Strength and Conditioning Research by the NSCA is rocking it. A couple weeks ago I woke up to the latest issue with a few new studies that were directly relevant and significant to endurance sport, and a few more than have their place for triathletes and runners.

We discussed three of the studies in the new ATC 202 podcast, if you want the verbal commentary featuring Lucho and yours truly, and below are my notes that recap the main points for ya’ll to get the bottom line and the takeaways, as well as notes on a couple other studies I enjoyed:



  • Followed triathletes from 1989-2014, examining the top 50 males and females from Olympic and Ironman races taking place over 26 years (2 sexes × 50 triathletes = 2600 for each distance). Due to dropouts, disqualifications and missing data the sample size was reduced to the data of 2440 triathletes (1341 males and 1099 females) in the Olympic distance.
  • Examined the changes in the individual contribution of each discipline to the overall performance of Olympic and Ironman distance triathlons among males and females. Overall performances and their component disciplines (swim, cycle, run) were analyzed.
  • Results suggest a higher competitive density across the years, where the triathletes from 11th to 50th place approximate their performances to the top 10.
  • For the Olympic distance, the split times in swimming and running decreased over the years, while the cycle split and total time remained unchanged for both sexes.
  • For the Ironman distance, the cycling and running splits, and total time decreased while swimming time remained stable, for both males and females.
  • The average contribution of the swim stage was smaller than the cycle and run stages for both distances and both sexes.
  • These findings highlight that the run matters most. Although, cycling fitness for Ironman is equally important as the run.
  • Swim had least importance to overall performance for both distances—but keep in mind this is for elite amateurs not pros. In ATC 202 Lucho I talk about how the swim matters so much in the Oly distance for pros if they want to make the lead draft pack and stay in the game.
  • Furthermore, swim is not irrelevant especially if you want to be competitive: “For Ironman distance triathlon, and in spite of the lower average swimming contribution, it is clear that this segment has been more important over the years, meaning that a better focus in swim training of Ironman triathletes can be beneficial to the overall performance, mainly when both cycling and running are very similar between competitors.”
  • But overall researchers said “strategies to improve running performance should be the main focus on the preparation to compete in the Olympic distance. Whereas in the Ironman, both cycling and running are decisive and should be well developed.”
  • “The present 26-year descriptive study shows that the time spent swimming is less predictive of the overall triathlon performance compared to time spent cycling or running in both Olympic and Ironman distances. Running is the stage with highest contribution in the Olympic distance, while in the Ironman, running and cycling contributed similarly to the overall performance…. For the triathletes that are not able to have an outstanding run, the Ironman distance could be a good option since cycling has also a decisive role in the overall performance.”

  • What I think? It’s actually a really dense paper if you get the full text, but at the end of the day it seems to simply validate what we already know about how we should train for triathlon and the different distances. Still, I think it’s great to see a longitudinal study like this.



  • I won’t lie, this study basically just confirms the obvious, but I can’t complain because it’s more good exposure for ultra in the research world!
  • Data were collected from the Craze Ultra-marathon held September in 2012 and 2013, respectively. Finishers of the 161km (N=47) and 101km (N=120) categories of the race were divided into thirds (Groups A-C)
  • The SHOCKING (lol) conclusion: “These findings demonstrate that to achieve a more even pace, recreational ultra-runners should adopt a patient sustainable starting speed, with less competitive runners setting realistic performance goals while competitive runners with a specific time goal to consider running in packs of similar pace.”
  • “The main findings of the study were that (i) pacing patterns during a 161-km and 101-km ultra-marathon remained consistent across different performance categories (ii) in the early portion of the race, top finishers tend to follow the leading runner while slower competitive finishers tend to form small packs with runners of similar pace (iii) faster finishers ran with fewer changes in speed than the slower finishers in the 101-km category and (iv) finishers remained conservative in their pacing over the last segment of the race when proximity to the end point is not known due to the absence of distance markers.”

  • A much slower start is required to achieve an even-pacing profile.
  • Speed increased again after last check point, but dropped by final 5k; disproving the third hypothesis that majority of the finishers will demonstrate an end spurt.
  • Top finishers showed a reverse-J shape in their pacing.
  • What I think? Understand the reality of your run fitness you bring to the table, don’t expect race day magic that you’ll go immensely faster than you’re capable of going, have a clear race plan but be flexible, and even though it’s tough to do try to pace as evenly as possible.



  • Fourteen recreationally active, trained distance female runners who were unaccustomed to unshod running were randomized to either unshod (barefoot) vs. shod (wearing shoes) for testing; all were inexperienced with unshod running.
  • Protocol was three 5-minute submaximal running trials at 65, 75, and 85% of VO2max. Other physiologic and perceptual variables such as respiratory exchange ratio (RER), lactate, heart rate (HR), and ratings of perceived exertion (RPE) were also measured.
  • Results: Submaximal oxygen consumption was significantly reduced at 85% of VO2max (P = 0.018), indicating an improvement in running economy (RE), but not during the 65% or 75% efforts.
  • The improvement in RE is most likely due to the removal of the shoe mass from the foot—altered inertial properties and reduced mechanical work of the unloaded. (Apparently the shoes were rather heavy too; average pair of shoes weighed 590 grams, ranging 460 to 800 g.)
  • They also attributed improvement to improved biomechanics when unshod.
  • “Bending stiffness of running shoes does not have a significant effect on racing performance, but rather may reduce performance because of added work performed on the shoe (and not the ground, where it can be returned for forward propulsion) during running. In summary, incorporating daily unshod activities in a variety of terrain may reduce running-related injuries due to positive structural and functional adaptations of the bare feet… For the recreational or competitive distance runner, training or competing while barefoot may be a useful strategy to improve endurance performance. Greater RE enables endurance athletes to utilize a lower percentage of their VO2max for a given velocity….”

  • Furthermore, this is applicable to marathon performance (not just 5ks, etc) for endurance athletes who are able to use a large percentage of their VO2max during longer races.
  • Females specifically measured because most studies on this matter have been with male subjects. And specifically they saw “other biomechanical factors favor RE such as low body fatness and leg mass that is distributed closer to the hip joint. In this study population, the thigh to calf ratio was inversely associated with VO2max and positively associated with body fatness.” But, thigh to calf ratio was not related to or an influence on oxygen consumption between the shod and unshod conditions.

“Athletes inexperienced with unshod running may perceive exposure of the bare foot to environmental conditions as high-risk. This perception does not have scientific support. Several unshod running studies have reported that the bare foot allows for greater proprioception that is associated with a reduction in running-related injuries (31-33). For example, increased barefoot weight-bearing activities such as indoor and outdoor walking and running leads to medial longitudinal arch shortening, which is a beneficial adaptation that increases the natural shock absorbing capacity of the foot (33). When in shoes, however, a false ‘sense of security’ is created due to deceptive advertising which results in unfavorable landing strategies that increase ground reaction forces (30).”

  • But I ask: Will these findings really translate to racing and/or outdoor training because this was done on a treadmill (which I would assume would be perceived as safer). Even they say, “Nevertheless, it is speculative whether these unshod running benefits would translate to improved distance running performance during actual competition outdoors.”
  • Also I question: Does it have to be training at 85% max to be done well? Are there detriments to slower barefoot running like more ground contact time and more pounding?
  • What I think? We should all build a body and biomechanics that allow for *some* barefoot training, but do so with caution and ease into it. We need to get over the idea that shoes are the be-all end-all. Learn to reconnect with your proprioception and natural connection with the ground!



  • This one examined active vs. passive recovery techniques on performance and physiological responses during short-distance, run-based repeat sprints (RS).
  • While cool for runners/triathletes who do intervals in their training program, it should be noted the premise of this study was geared toward team-based sports like soccer and basketball where athletes are constantly changing pace in a game for long durations—as opposed to endurance athletes who use sprints in practice to increase fitness but don’t usually race with this approach.
  • Results: Passive recovery promoted superior performance, while activity recovery led to greater physiological loads (more energy cost) and earlier performance deterioration, meaning more of a drop off in sprint speed during latter sprints using active recovery.
  • Limitations: Only 9 subjects who were sports science students, not listed as athletes but did workout up to at least 150 minutes a week. Six males, three females.
  • The RS protocol consisted of 10 x 20 m run-based sprints with 30 seconds of either active or passive recovery between sprinting bouts. The active recovery protocol involved subjects decelerating following each sprint and then continuously jogging at 50% of maximal sprint speed. The passive recovery protocol involved subjects decelerating and then standing.
  • Of note: They had a 5min run warmup for 5 min and dynamic stretching prior to each test.
  • With active recovery they observed significantly higher blood lactate levels and RPE than passive recovery immediately and 5 min following.
  • Why was active recovery not as effective? Reduced RS performance with active recovery has been attributed to various sources, including increased O2 requirement in working musculature to complete submaximal workloads between sprinting bouts. On the other hand, the reduced O2demand during passive recovery likely allows for increased PCr availability across sprints.
  • If you are looking to maintain performance in your sprints and not drop off, understand that latter bouts rely more on oxidative metabolism, so you might be better off stopping and standing between sprints to “save” that oxygen for the work interval.
  • Passive recovery also allowed for more for lactate oxidation than active—meaning, improved lactate clearance.
  • What I think? I like this! I often like prescribing 6 intervals and watching the trend of performance. Research lines up with what I usually see: a decrease from sprint #4 on. But that’s usually when using an active recovery protocol i.e. spinning out on the bike or a light jog. Maybe if we just stopped we’d be better off during our sprints?



  • This one is cool. They researchers looked at different muscle activation patterns when knees were malaligned during a squat compared with the control squat done with normal “perfect” form. This is good for athletes looking to get the most out of their squat and not add to imbalances.
  • What they found:
  • 1) Decreased quadriceps activation associated with medial malalignment (valgus knee collapse) indicating that frontal plane deviations during a squat alters muscle activation strategy to stabilize the lower extremity during a bilateral squat.
  • 2) Gastrocnemii (calf) activation increases when knees cave in and/or knees are unstable. “Increased co-activation of the gastrocnemii during closed kinetic chain exercises stabilizes the ankle during flexed knee stance and decreases the strain at the anterior cruciate ligament by pulling the femur backwards.” This isn’t good for those endurance athletes with already-tight calves and/or calf injury.
  • 3) Bicep femoris (hamstring) activation also increase in malaligned squats, which researchers said is a natural stabilizing technique of the body. This doesn’t mean it’s a good thing though.
  • Co-contraction of the biceps femoris and gastrocnemii during parts of the squat cycle when contact forces are highest may be a strategy to stabilize the hips, knee joint and ankle.
  • Anterior knee displacement—knees falling forward in front of toes—must be watched. As the knees move anteriorly during the descent for the squat in an excessive manner, the shear forces increase. This study covers that issue in more detail.
  • Malaligned knee positions may be potentially injurious, and the iIncreased co-contraction of the knee flexors and gastrocnemii is the body trying to self-correct but it does not solve the underlying problem of needing more stability. If you see your knees wobbling, valgus collapse or knees falling too far in front of the toes, this is a sign you need to work on strength and stability to save your hamstrings and calves from injury while running.
  • What I think? We all should assess our squats because it totally has implications for what we’re doing in our sport, especially running!