Treadmill enforces Zone 2 pacing

Runner’s World published a May 15 training article recommending treadmill running as a practical way to keep easy runs in Zone 2, the low-intensity aerobic range many runners use for base training. The piece, written by Kristine Kearns, argued that the machine’s fixed pace can help runners avoid gradually speeding up during sessions meant to stay controlled. Runner’s World’s RSS feed listed the story on Friday with the description, “A simple way to stay in zone 2.” The article appeared as interest in Zone 2 training continues to spread across recreational running and wearable-device coaching. ### Why did Runner’s World single out the treadmill for easy runs? Kristine Kearns wrote on May 15 that the treadmill can work as a pacing aid because the belt keeps moving at a set speed unless the runner changes it. That differs from outdoor running, where terrain, weather, traffic stops and competitive instinct can all push pace up or down. Runner’s World framed that setup as a way to reduce “effort creep” on easy days. The article said the treadmill can keep pace and heart rate steadier than an outdoor run, where small surges often turn an aerobic session into something harder. ### What is Zone 2 in this context? Runner’s World has described Zone 2 elsewhere in its training coverage as an easy aerobic intensity used to build endurance without the strain of harder workouts. In a separate April 23 article, the magazine said Zone 2 still matters even for runners without a race on the calendar. COROS, a maker of GPS sports watches that publishes coaching material, says easy runs are designed to sit in the aerobic endurance range and are used to build endurance while supporting recovery. Marathon Handbook, in a guide to heart-rate zones for runners, similarly says runners often use heart-rate training on easy and recovery days to stay in the intended aerobic zone. (runnersworld.com) ### How does a treadmill change the workout compared with running outside? Runner’s World said the treadmill’s main advantage is consistency. A runner who sets a speed can stay there for long stretches, which makes the session less vulnerable to hills, stoplights, wind or the tendency to chase a faster split late in the run. The magazine’s May 15 article said that consistency can make the treadmill useful for pacing drills and steady aerobic sessions. (coros.com) The argument was not that treadmill running is inherently better than outdoor running, but that it can serve as a tool when the goal is to keep intensity capped. ### What evidence is there that Runner’s World published this on May 15? Runner’s World’s latest-content RSS feed stamped the treadmill story at 17:53:15 UTC on Friday, May 15, 2026. The feed entry linked to the article URL referenced in the user’s prompt and summarized it as “A simple way to stay in zone 2.” Runner’s World’s gear page also listed the story on May 15 under the headline, “Struggling to Keep Easy Runs Easy? Here’s the Tool That Can Keep You Going at the Right Intensity,” with Kristine Kearns named as the author. ### Where does this fit in Runner’s World’s broader coverage? Runner’s World has published multiple training pieces in 2026 on aerobic development, treadmill workouts and Zone 2 running. (runnersworld.com) The site’s training page listed “No Race Goal? Here’s Why Zone 2 Still Matters” on April 23, while its treadmill coverage has included articles on treadmill-specific workouts, form mistakes and indoor training plans. (runnersworld.com) The May 15 article adds a narrower claim to that stream of coverage: that the treadmill can be used not only for convenience or bad-weather running, but as a control mechanism for easy-day intensity. That framing came from Runner’s World and its writer, not from a governing body or formal training standard. ### Where can readers find the next step? Runner’s World’s May 15 story remains available on the magazine’s website through the article page referenced in its RSS feed and site listings. (runnersworld.com) The publication’s training and treadmill sections continue to carry related guidance on Zone 2 running, pacing and indoor workouts. (runnersworld.com)