There is no good evidence that shock-absorbing insoles, used to reduce impact and minimise muscle, tendon, and bone damage, do actually stave off injuries or stress fractures, say researchers.
They based their conclusion on a pooled analysis of available data, published in the British Journal of Sports Medicine.
The researchers noted that the most common overuse injuries associated with physical activity included medial tibial stress syndrome, Achilles tendon, plantar fasciitis and knee pain.
They highlighted that contoured foot orthotics, which aim to redistribute pressure and alter neural sensory feedback and gait while walking or running, and soft insoles, which aim to soften impact, were often used to stave off injury risk and manage existing musculoskeletal conditions.
To find out how effective these were, the researchers trawled through research databases for relevant studies published up to June 2016.
They found 11 clinical trials relating to foot orthotics and seven that had evaluated shock-absorbing insoles.
When the data were pooled together, the results showed that foot orthotics cut the risk of overall injury by 28%, and of a stress fracture in the legs and feet by 41%.
However, they did not stave off the risk of tendon/muscle injury, including Achilles tendon, and knee and back pain.
In addition, shock-absorbing insoles did not lessen the risk of any type of injury. The data from one trial even indicated they increased the risk, said the researchers.
The study authors cautioned that further rigorous research was needed on the issue because the quality of the studies they analysed “varied considerably”.
Additionally, the said that much of the available evidence came from the use of insoles and orthotics in military personnel, whose exercise regimes and footwear were unlikely to be representative of those of the general population.