Preventing running injuries with smart insoles

More than half of all runners experience injuries, which often leads to exercising less or even quitting. Because inactivity leads to health risks, movement scientist Bas Van Hooren of Maastricht UMC+ investigated whether smart soles that provide feedback on running technique and speed while running lead to fewer injuries. And he determined which strength exercises are most effective in preventing injuries. On 17 June, Van Hooren, an athlete himself, will receive his PhD on his research into injury prevention and improving sports performance.

Running injuries such as knee problems, Achilles tendon problems and shin injuries are common among runners. These injuries are often the result of overuse, where the force exerted on bones, muscles and tendons exceeds what those tissues can handle. There are two ways to restore this balance: reduce the load, and strengthen the muscles, tendons and bones. In the movement lab, the load and strength of muscles, tendons and bones can be accurately measured, but the ordinary runner cannot go to the lab for a 3D movement analysis. Therefore, Van Hooren investigated how to bring this technology to people using smart insoles.

Smart insoles

While running, the special insoles measure stride length, contact time (how long the foot touches the ground) and flight time (how long the foot is off the ground), among other things. In a comparison with 3D analyses from the lab, Van Hooren showed that the orthotics can measure the load on the knees, Achilles tendon, and shins quite accurately. "Although the method can be further personalized, the smart orthotics can measure more accurately than traditional sports watches, which often significantly overestimate injury risk," van Hooren said.

Moreover, the insoles proved effective in preventing injuries. "While running, the insole provides feedback via an app when the load on the knee, for example, is too high, such as 'try to shorten your stride length' or 'try to land more on your forefoot'," explains van Hooren. Over time, runners who received this feedback had fewer and less serious injuries than runners who did not receive this feedback. "So with wearable technology, we can actually prevent injuries." The study involved 220 people.

Strength training

Besides reducing strain, Van Hooren also focused on improving load capacity through strength training. He specifically examined the hamstrings because injuries to these muscles are common in team sports involving running. Explosive running during sports such as football often leads to hamstring injuries, which also often recur.

Preventing these injuries is relatively easy through targeted hamstring training, where both muscle strength and muscle fibre length are important. Both aspects can be improved with strength exercises, but there are about a hundred different exercises, all of which are differently effective. Van Hooren used 3D motion analysis and ultrasound to investigate what happens to muscles during the three most common strength exercises. His research shows that the nordic hamstring curl is most effective at improving the strength of two of the four hamstring muscles, and at increasing the fibre length of the hamstring muscle most commonly injured.

Rehabilitation

Van Hooren continues his research on injury prevention by investigating which exercises can increase the load capacity of the Achilles tendon. He is also expanding his study on the smart sole: "We are looking at how we can make the insole provide a reliable estimate of the recovery time needed after exercise, so that we can use it for a personalized sports programme. We are also investigating whether we can use the insole in rehabilitation, both for sports injuries and conditions such as osteoarthritis, to promote recovery.

Author: Annemarie Stiekema