Lightweight trainers mean less impact, less fatigue and faster recovery
By Danny Abshire, co-founder, Newton Running
Wearing lightweight shoes and running with soft footsteps can be very beneficial for a runner of any ability or experience level.
If you have good form with a natural running (midfoot/forefoot) gait and you wear lightweight shoes, running can put you in a state of euphoric bliss as you effortlessly click off the miles. Everything flows together harmoniously and efficiently, no matter if you're running a minute or a marathon.
But if you have inefficient form and wear heavier, overbuilt shoes — and the two often go hand-in-hand — the simple act of running can quickly become very destructive to your body. Heavier training shoes typically weigh more because they have built-up heels, which translate to steep ramp angles of 8 to 15 percent. This encourages a heavy heel-striking gait and braking, both of which have been shown to cause a variety of overuse injuries.
Conversely, lightweight training shoes that have a very low heel-toe slope (5 percent or less, such as Newton Running shoes, which have ramp angles under 1.5 percent) encourage more of a natural running gait in which the foot hits the ground very lightly and almost level near the ball of the foot (very similarly to how a bare foot would engage the ground).
So how light is lightweight? Modern materials and manufacturing techniques — including less stitching, fewer overlays and lighter midsoles — are allowing shoes to get lighter and lighter. Training shoes still range from 7.5 to 9.5 ounces (depending on gender and shoe size) to 11.0 to 12.5 ounces. Two or three ounces might not seem like much, but you can feel the difference on your feet once you lace your shoes up and you'll certainly feel the effects after a long run.
But while lightweight shoes are better for all runners (especially when engaging in an efficient natural running gait), it's not only the actual weight that makes the difference. It's also about how the shoe is built and how much downward energy it can convert into forward propulsion. The Action/Reaction Technology™ in Newton Running converts impact energy into forward motion with up to 67 percent more energy return than traditional EVA foam midsoles.
However, that kind of midfoot/forefoot gait does not mean running on your toes like a sprinter. Instead, allow your foot to strike directly under your body and lift your foot off the ground instead of pushing off hard like a sprinter. Practice this method of landing lightly, let the foot settle level to the ground, then lever forward and lift the foot off the ground.
The benefits to wearing lighter shoes include less braking (and therefore less impact), less muscle strain and less energy output because you're lifting the weight of the shoe off the ground instead of using excessive muscular force to push off the ground.
Simple math says if you're carrying an additional 2 ounces over 25,000 steps in a half marathon or 50,000 steps in a marathon, it means you're lugging an extra 3,000 to 6,500 pounds to the finish line. And the difference of the impact transients — the forces that shoots up your body upon your foot's impact with the ground — is considerably more with a heel-striking gait in a heavier shoe than it is with a lightweight shoe that promotes an easy midfoot/forefoot gait. The combination of all of these factors means you endure less physical exertion and less fatigue in a lightweight shoe, and that ultimately means you'll recover faster.
There's a simple way to experience the metabolic differences of running with a lightweight, minimally constructed shoe compared to running in a shoe that's several ounces heavier. After warming up, run a mile in a pair of 12-ounce trainers on a track at a pre-determined pace (say 8 minutes, which means 60 seconds for every 200 meters) and record your heart rate data with a heart rate monitor. Then lace up a pair of 9-ounce trainers and run another mile at the same 8-minute pace. You'll likely find your heart rate is 5 to 10 percent less during the second mile when you're wearing lighter shoes, even though each mile was run at an identical pace.
The bottom line is that the weight of your training shoes can play a big role in how efficient you are as a runner. Lightweight shoes, especially ones that allow you to run with a natural gait and soft midfoot/forefoot footstrikes, can lessen muscle strain and fatigue, improve your endurance and help you recover faster, all factors in improving your running. But if you're considering changing your running form or the style of shoes you wear, do it gradually and carefully to avoid injury.
Danny Abshire is the co-founder of Newton Running, a Boulder, Colo.-based company that makes shoes that promote an efficient natural running gait. He has been making advanced footwear solutions for runners and triathletes for more than 20 years.
