Super Shoes Bring Records and More Injuries
Not only athletes are constantly refining their technique to improve performance, but their clothing is also optimized wherever possible. Modern super shoes, for instance, enable professional athletes to achieve peak performances, according to studies. However, a German expert warns that the high-tech shoes also increase the risk of injury.
Super shoes and super spikes with thick foam and carbon elements seem to help elite athletes set new records. Two studies now investigate whether there is a real connection between technology and performance.
A German biomechanics expert warns, however, that high-tech shoes increase the risk of injury and advises hobby runners to avoid them completely.
Shoe doping
At the 2016 Rio de Janeiro Olympics, the three best men in the marathon wore a pair of new running shoes from sportswear giant Nike with noticeably thick soles. The carbon elements and innovative cushioning systems in the shoes apparently gave the athletes a significant advantage, leading some to speak of unfair "technical doping." Not all marathon participants had the opportunity to compete with the super shoes.
However, the new shoes were not banned. Specific rules on shoe innovations were only published in 2020 by World Athletics (WA), the governing body of all national athletics federations. These rules, for example, prohibit professionals from wearing shoes with a midsole height of more than 40 millimeters. This does not stop manufacturers from producing models for recreational use that are even thicker and softer - following the motto "more is more."
But whether this is really true was investigated by a research group at ETH Zurich in a test with 16 well-trained runners. They ran on a track in shoes with 30, 40, and 50 millimeters (mm) thick midsoles, comparing running economy, comfort, and several biomechanical variables each time. Running economy refers to the ratio of oxygen consumed to a given running performance: the better the running economy, the less oxygen is consumed at the same running speed.
The 40-mm shoe offered the greatest comfort and, together with the 50-mm shoe, the best running economy. The 50-mm shoe had no advantages in this regard. No differences were found between all three groups in ground contact, step frequency, and step length, according to the study presented at the 42nd conference of the International Society of Biomechanics in Sports in Salzburg in mid-July.
To new records with super spikes
Shoe innovations are also taking place on shorter distances and in other athletics disciplines - as demonstrated by the 2020 Tokyo Olympics. Several athletes set records there with their feet in high-tech running spikes - also known as super spikes.
Spikes have small spikes on the sole that improve grip and allow better force transmission. In super spikes, the midsole is equipped with carbon elements and special dynamic foams, similar to marathon shoes, making them lighter, softer, and more dynamic.
A study by a U.S. research team suggests that the so-called Super-Spikes may have played a larger role in Olympic records. The group recruited nine well-trained men and had them run on a special treadmill in different shoes. Indeed, the running economy was slightly better with the Super-Spikes, which could translate to a 1-1.5% improvement in times, according to co-author Geoff Burns. "An improvement in economy of 1.5-2.0% can make the difference between a medal race and not qualifying for the Games in an elite runner," Burns is quoted as saying.
Injuries come with top performances
Biomechanics professor Gert-Peter Brueggemann also sees a connection between the records of recent years and the new shoes - both the long-distance super shoes and the Super-Spikes. However, injuries have also increased at the elite level, according to Brueggemann, who led the Institute for Biomechanics and Orthopedics at the German Sports University in Cologne for many years.
According to Brueggemann, athletes and several studies report problems particularly in the knee, the Achilles tendon-shin complex, and the midfoot and ankle. The latter could, according to a 2023 study, lead to fatigue symptoms such as stress fractures.
Regarding the new shoes, the expert explains that more foam is used, which causes the body to be positioned higher. At the same time, carbon elements stiffen the sole lengthwise, which puts more strain on the Achilles tendon and the midfoot. The biomechanics of the shoes could thus lead to overloading of the very areas where athletes complain of problems. "We rarely see such clear connections between biomechanical loads and orthopedic outcomes," says Brueggemann.
Like jumping on a trampoline
He recommends athletes to run as little as possible in such competition shoes during training - but the body also needs enough time to get used to the technology and learn to handle the soft shoes. It's "like jumping on a trampoline, where the leg muscles need to be tense enough to use the trampoline."
However, Brueggemann advises recreational runners to avoid such super shoes - also based on a study of his, the full results of which will be published soon. More than 400 hobby runners were observed for six months - and assigned different shoes by random: one group wore a super shoe, another ran with standard shoes, and the third group was equipped with so-called U-TECH shoes. In these shoes, the cushioning elements are not under the heel, but horseshoe-shaped around it - Brueggemann had accompanied the development of such shoes as a scientific advisor.
Indeed, the injury risk in the super shoe group was more than 30% higher than in runners with standard running shoes, according to a result of the study. The shoes with the horseshoe-shaped elements, however, reduced this risk by 60%, according to Brueggemann - and showed: "We can control loads and ultimately injury risk through technology."
The research at ETH Zurich found that shoes with 40mm thick midsoles offered the best running economy and comfort among three different options. The study on hobby runners led by Gert-Peter Brueggemann revealed that the injury risk in the super shoe group was significantly higher than with standard running shoes, but the use of shoes with horseshoe-shaped cushioning elements reduced this risk.
Despite the advantages of super shoes and super spikes in achieving better running economies and performance, these high-tech shoes also increase the risk of injuries, particularly in the knee, Achilles tendon-shin complex, and midfoot.
