Carbon technology in shoes: How it works, top brands, cost-benefit analysis

“Carbon-plated running shoes have one or more rigid plates made of carbon built into the midsole. Carbon is used because it can withstand heavy loads on the one hand, but on the other hand it is very light. Running shoes should naturally be as light as possible, at least in competition. The carbon plate ensures energy recovery is increased with every step, which in turn improves running dynamics. As a result, we can achieve a slightly faster pace with the same amount of energy compared to the usual running shoes,” explains Khurana.

Cost-benefit analysis

With supply and pricing pressures easing out, carbon shoes have become relatively accessible. For champion runners, the gains from these shoes are marginal yet significant as the minor difference could mean a new record or a gold medal.

For recreational runners the difference could be significant. A 4 percent improvement for a 4-hour marathoner translates to shaving about 10 minutes. Pune-based Murli Pillai, who is preparing to run the Comrades Ultra in South Africa this year, has stayed away from the carbon shoes only because they are too expensive, and he thinks he is too slow to benefit from those. “Having seen the math and the kind of difference these carbon shoes can make, I am a bit more convinced about trying them. The only thing holding me back is the high prices,” he says.

Delhi-based running coach Gagan Arora has used carbon shoes for his races and says these are race days shoes. “They should be used only on race day. They work well for people who are fast and can hold a 4-4:30 minutes per kilometre... They are great for those gunning for the podium but could suck for many people,” he says.

Remember, you will need to have a separate pair of shoes for training if you go for the carbon shoes for race day. You can’t train too much in carbon shoes as they tend to wear off quicker than training shoes. Carbon-tech shoes are race-day ready; they don’t really need breaking in. Kavitha Reddy, a veteran of several marathons including the New York City Marathon and Tokyo Marathon, has a pair of Nike Vaporfly Next% 3. Reddy says, “As long as you are familiar with the carbon shoes you are wearing you can use them right away.”

However, both Khurana and Zaini say despite the new advanced materials you must use the shoes a couple of times at least before race day. “It is not so much as breaking them in but getting yourself conditioned to the shoes. You need a couple of runs to get used to the shoes so that you aren’t caught by surprise on race day,” suggests Zaini. Khurana adds, “In order to get the desired results, it is imperative that you have at least a couple of decent runs in those pairs.”

Design changes

Different brands use different carbon reinforcements in the midsole. Some use two plates while some others use rods. Nike, Asics and Puma use a carbon plate for its premium racing shoes while Adidas uses carbon rods in the midsole of its new-age Adizero racing range. Both designs have been successful.

There are other minor but important design tweaks in carbon shoes in order to reduce weight and improve running economy. The most visible change is the seriously thick sole, especially under the heel area. Older race-day shoes used to have thinner soles as racing shoes had to be lighter than training shoes and often, they used to have a small heel to toe drop. Not anymore. Along with the thicker soles, which are needed to house the carbon tech, the heel to toe drop has increased. “On the recently released Nike Vaporfly Next% 3 the stack height of the sole is slightly higher under the forefoot area in order to create a concave shape that creates a rocking motion and aids the running economy from heel or mid-foot strike to toe-off during a stride,” says Mohamed Zaini, Nike’s EKIN manager for Southeast Asia and India.

While the weight of the thicker midsole was reduced by developing lighter foams, the next area of the shoes to change for weight reduction was the outsole. All carbon race-day shoes have a thin outsole and only in the high-contact areas. The softer midsole and thin rubber outsole only in certain areas mean these shoes wear out faster than regular running shoes. Also gone from these new race-day shoes are the foam padding around the ankles and the tongue. Instead what you get is a sock-like upper that fits and feels like a sock, which plays a big part in bringing down the weight of the shoe.

Performance and fine print

The reason runners weigh getting a pair of carbon shoes for race day is because of the promise of better performance. The greater stack height of the sole gives better energy return upon ground strike while the carbon plate works in tandem with the sole to give extra propulsion and both combine to improve running economy, which translates to faster runs.

An analysis of thousands of marathoners—both elite and recreational—has shown that carbon shoes help shave off minutes from your race times achieved in non-carbon shoes. By how much depends on your pace and training. While the gains among the elite are marginal, recreational runners who complete a full marathon between 3 and 4 hours have reported gains of 8-10 percent, which is significant and could mean improving your personal record.

However, it is not only about the shoe. It depends on your training, says Zaini. “How much impact a carbon shoe would have on your time totally depends on you and your training. In order to reap the maximum benefits out of your carbon shoes, you need to stick to a good training plan and perform well in your training runs,” he adds.

Along with the benefits of these shoes, there are a few things one should keep in mind. You have to pay a premium to purchase a shoe that has a carbon plate in it. Some of these shoes, such as Nike’s Alphafly and Vaporfly Next% are still made in limited numbers because only serious runners use them so finding a pair that fits you in a colour you like can be a challenge. Also, the durability of carbon-running shoes may be reduced due to the stress on the carbon plate, warns Khurana, adding, “It’s also important to note that carbon running shoes may only be suitable for some runners and may cause injuries if overused.”

Recommendations

If you are looking for a pair of race day carbon shoes here are our brand-wise recommendations in alphabetical order:

Adidas Adizero Adios Pro 3

Price: Rs 24,999

This pair ruled the Boston Marathon this April. Adidas came late to the party and uses carbon rods, instead of a carbon plate, in its midsole in this race day shoe. Housed inside its new Lightstrike Pro foam, the carbon rods have been working much better than the Yeezies for the German sports brand.

Asics Metaspeed Sky+ and Metaspeed Edge+

Price: Rs 21,999

Not all runners are alike and not all carbon shoes work for everyone. You need to find a pair that suits you and your running style. Asics offers two options in its top-end race-day shoes. Try both before settling on one of these shoes that are a big hit among triathletes.

Nike Vaporfly Next% 3

Price: Rs 20,695

The third edition of Nike’s carbon shoes for serious runners uses the Zoom X foam and has introduced its popular sock-like Flyknit upper in this pair. It is best-suited for distances up to the marathon. For distances beyond that you are better off using the Alphafly.

Puma Deviate Nitro Elite 2

Price: Rs 17,999

Puma’s carbon shoes are on the affordable end of the spectrum and have a proven track record with a Puma runner finishing on the marathon podium at the Tokyo Olympics. The regular Deviate Nitro 2 sport the same foam but a different carbon plate from the one used in this version and are about 70 grams heavier. You are paying the premium for the lighter weight.