Welcome to the latest edition of Run Long, Run Healthy! This week, we dive into a range of fascinating studies and insights that can help you optimize your training and improve your running performance. From the surprising benefits of sprinting for distance runners to the accuracy of smartwatch predictions and the impact of training on heart health, we’ve got a lot to cover.
We’ll also explore how running on uneven terrain can boost your fitness, the potential link between CBD and endurance, and the age-old debate of polarized versus pyramidal training. Plus, we’ll share some quick nuggets of wisdom, including Clayton Young’s Road to Boston and a controversial take on Advil sponsorships in the running world. Let’s get started!
Can Sprinting Make You a Better Distance Runner?
Runners often equate mileage with improvement, but a recent study suggests that incorporating sprints into your routine could be a game-changer. Researchers found that distance runners who swapped some long runs for sprint interval training (SIT) saw significant gains in key endurance metrics. The SIT group, performing 10×30-second all-out sprints with rest, twice a week for six weeks, outperformed the traditional training group.
After six weeks, the SIT group showed improved time to exhaustion, a faster 3,000-meter time trial, and better 100-meter and 400-meter times, indicating enhanced speed and neuromuscular efficiency. Interestingly, while VO2 max didn’t significantly improve, running economy did, meaning these runners became more efficient.
After six weeks, the SIT group outperformed the traditional group in key endurance metrics: They had an improved time to exhaustion (a key indicator of endurance), a faster 3,000-meter time trial time (experiencing a ~5-second improvement versus no change in the traditional training group), and faster 100-meter and 400-meter times (suggesting better speed and neuromuscular efficiency).
This study highlights that sprint intervals aren’t just for sprinters. Even short strides can help improve your running efficiency and performance. Consider strategically adding 1–2 SIT sessions per week to your base training to see real benefits.
Smartwatches Predict Race Times (At Least the Short Ones) with Surprising Accuracy
Smartwatches have become indispensable tools for runners, providing real-time data and performance predictions. But how accurate are these predictions? A new study put a smartwatch’s algorithm to the test, comparing estimated race times to actual performances of 154 amateur runners. The results are quite impressive.
The study found that the smartwatch’s predictions were within 3% of actual times in most cases, achieving an accuracy rate exceeding 97%. It predicted 5k times within approximately 20 seconds and 10k times within about 4 seconds. However, the accuracy decreased with longer distances, with half marathon predictions having an error of about 2.5 minutes.
Overall, the smartwatch’s predictions were within 3% of actual times in most cases, meaning an accuracy rate exceeding 97%. It was able to predict the runners’ 5k times within ~20 seconds and their 10k times within ~4 seconds. The prediction accuracy faltered as the distance increased — half marathon prediction times had an error of about 2.5 minutes.
For pacing guidance and goal setting, your smartwatch is likely a reliable predictor, especially for shorter races like 5k and 10k. However, remember that longer races introduce more variables, making predictions less accurate.
How Men’s and Women’s Hearts Adapt Differently to Training
Resistance and endurance training lead to different heart adaptations. A recent study investigated how men’s and women’s hearts respond to these training types. Researchers recruited 64 untrained individuals and randomized them to 12 weeks of endurance training (running & cycling) or resistance training (strength workouts), then switched modalities after a washout period.
Endurance training generally led to healthier heart adaptations. Resistance training in men resulted in thicker heart walls but worsened diastolic function (potential stiffness). Endurance training improved the size of the heart’s chambers and its ability to fill and pump blood efficiently.
Men’s hearts responded more to resistance training — left ventricle size increased significantly. Furthermore, men showed signs of worsened diastolic function after resistance training — the heart became stiffer. Women showed no major cardiac changes after resistance training. Women’s hearts adapted more to endurance training.
Endurance training improves heart structure and function without adding stiffness, especially for women. Prioritize aerobic work while strategically integrating strength training for musculoskeletal health and long-term cardiovascular benefits.
Running on Uneven Terrain is More Challenging — Which Could Make You Fitter
Running on various surfaces offers unique benefits. A study tested runners on even versus uneven terrain to see how each surface affects energy use and muscle activation. Runners completed two 6-minute runs on an indoor track with smooth and unstable surfaces while researchers measured their physiological responses.
Running on rough surfaces required significantly more energy. Runners needed 18% more oxygen, expended 23% more energy, had a 10% increase in heart rate, and rated the session as 50% harder. Muscle activation was higher during uneven terrain running, particularly in stabilizing muscles.
Compared to even terrain, running on rough surfaces required significantly more energy: runners required 18% more oxygen, expended 23% more energy, had a 10% increase in heart rate and a 7% increase in their breathing rate, and rated the session as 50% harder than running on even surfaces.
Adding trail or uneven-surface running can improve efficiency and strengthen your stabilizers. Start gradually if you’re new to trail running to avoid soreness and injury.
The Surprising Link Between CBD, Gut Health, and Endurance
A new study in mice suggests CBD might enhance endurance by reshaping the gut microbiome and boosting mitochondrial function. Mice treated with CBD ran longer and farther than controls, with changes in muscle fiber composition and increased mitochondrial activity. These benefits were linked to alterations in gut microbiota, particularly an increase in Bifidobacterium animalis KBP-1.
Mice treated with CBD ran longer and farther than controls. CBD also shifted muscle fibers to a more oxidative (endurance-oriented) profile — with an increase in slow-twitch (type I and IIa) fibers, which are more fatigue-resistant, and a decrease in glycolytic (type IIb or “fast twitch”) fibers.
While human studies are needed, the idea that gut bacteria can enhance endurance is gaining traction. Future endurance supplements may focus on CBD and targeted probiotics.
Polarized vs. Pyramidal Training for Endurance Gains
Polarized training emphasizes easy (Zone 1) and hard (Zone 3) workouts, with minimal Zone 2. Pyramidal training follows a similar structure but includes more Zone 2 work. A meta-analysis compared these models, analyzing data from 13 studies. Competitive athletes benefited more from polarized training, while recreational athletes improved more with pyramidal training.
Overall, there were no major differences between polarized and pyramidal training when looking at all athletes together. Both training models produced similar gains in VO2 max and TT performance. However, competitive athletes benefited more from polarized training. On the other hand, recreational athletes improved more with pyramidal training.
The best approach depends on your experience level. Experienced athletes may see better gains with polarized training, while those building aerobic fitness might benefit more from a pyramidal approach.
Conclusion
This week’s research roundup offers valuable insights for runners of all levels. From incorporating sprint intervals to understanding smartwatch accuracy, heart adaptations, and the impact of terrain and supplements, these findings can help you refine your training and improve your performance. Experiment with these strategies to find what works best for you, and always prioritize listening to your body.
Remember, running is a journey, and staying informed is key to running long and healthy. Keep pushing your limits, and embrace the challenges along the way. Until next time, happy running!