Fast 5K Key #18: Wear Light Racing Flats

Fast 5K: 25 Crucial Keys and 4 Training Plans by Pete Magill is your guide to your fastest 5K race. Celebrated running coach Magill shares the essential keys to 5K fitness and race readiness and offers four training plans to prepare you for race day.

Key #18: Wear Light Racing Flats

“The man who moves a mountain begins by carrying away small stones.” —Adapted from a fable by Liè Zĭ, Taoist philosopher


Here’s a quick way to drop a minimum of 9–18 seconds from your 5K time without having to train or diet: Race in a lighter pair of shoes.

Research has found that decreasing the weight of your racing shoes by 3.5 ounces per shoe will improve your 5K time by about 1 percent. The average training shoe weighs 11–12 ounces, while most racing flats tip the scales at about 6–8 ounces, with the lightest racing flats boasting a barely there 4 ounces. By switching from training shoes to the light­est flats, a 20-minute 5K runner can cut about 24 seconds from his or her time—12 seconds if he or she is already racing in 7–8-ounce flats. A 30-minute 5K runner would gain 18–36 seconds. A 15-minute runner would improve 9–18 seconds.

And it gets better. By running your hard workouts—tempos, hills, drills, and repetitions—in lighter shoes, you’ll improve the efficiency of your stride at faster paces. Some runners mistakenly believe that doing hard workouts in heavier shoes strengthens their legs, making race-day running in lighter shoes much easier. Not so. Instead, doing hard work­outs in heavy shoes simply hardwires a stride that’s slightly different than the one you’ll utilize with lighter shoes. The result is a less-efficient stride in the lighter shoe come race day. If your aim is to race fast and efficiently in lighter shoes, then practice running fast and efficiently in lighter shoes.

One caveat to this key: There’s a point at which lack of cushioning outweighs the benefit of racing in a lighter flat—and research has shown that barefoot running is the least efficient race choice of all. As a rule of thumb, if your feet hurt due to lack of shoe, add a little more shoe.

Shoe Weight vs. Performance Improvement

Fast 5K by Pete Magill F5K 30 minute runner 600x340

Fast 5K by Pete Magill F5K 25 minute runner 600x340

Fast 5K by Pete Magill F5K 20 minute runner 600x340

Fast 5K by Pete Magill F5K 15 minute runner 600x340

These charts illustrate possible performance improvement for runners of different abilities, based upon the weight of their racing flats. The 12-ounce weight represents the heavy side and assumes the runner is racing in training shoes. The 3-ounce weight represents the light side, and shoes that weigh less than 3 ounces offer no advantage (in fact, studies show there is a disadvantage to shoes lighter than this, as well as to barefoot running).

Fast 5K: 25 Crucial Keys and 4 Training Plans by Pete Magill is your guide to your fastest 5K race. Celebrated running coach Magill shares the essential keys to 5K fitness and race readiness and offers four training plans to prepare you for race day.