Bonacci et al. found that runners in the Nike Free 3.0 had Adidas Superstar Womens reduced stride length and increased cadence compared to running in their Nike Air Max 1 Dámské standard conventionally cushioned running shoe. Reduction in stride length and an increase in cadence have been associated with reduced loading at the knee and the hip. However, the Free 3.0 did not alter their foot strike or most other parameters that were measured. When running barefoot, these same runners had a significantly less dorsiflexed ankle at contact (flatter foot strike) and significantly reduced midstance knee flexion compared to all shod conditions. A difference between this study and the Willy study mentioned above is that runners in the Bonnacci study were given 10 days to acclimate the the more minimal footwear and they ran overground versus on a treadmill. These factors could explain the contrasting findings for stride rate and stride length.Potthast Nike Air Max 90 Mens Black et al. found that individuals who exercised in Nike Free shoes Nike Roshe Run Femme experienced a 20% increase in toe flexor strength. In another abstract the same group reports that exercising in Nike Free shoes also increased ankle plantarflexor and dorsiflexor strength. It is important to point out that these studies were looking at general exercise effects, no specifically running
If you look at these results, we find that there may be some benefit to trying a shoe like the Nike Free from a foot strengthening standpoint (it’s likely that different shoes simply strengthen the body in different ways, maybe not that one is inherently better than another), and they may encourage a shorter, quicker stride with some amount of acclimation. The latter may lead to reduced loading of the knee/hip over the long term, but we don’t currently have data to support Nike Air Max 95 Homme that.
However, we also see that impact loading can significantly Nike Air VaporMax Dámské increase initially for heel strikers in a moderately cushioned minimal shoe like the Nike Free 3.0. This is cause for concern, especially since Willy et al. report that “…the average vertical loading rates that we found during minimalist shoe running exceeded the values reported in runners with a history of tibial stress fractures by Milner et al. (78.97 bw/sec, ± 24.96).” Furthermore, there is some evidence that runners transitioning into a shoe like this are at higher risk of injury (over one-third of the runners that transitioned into the Free 3.0 in the Ryan study got hurt).
So at least for the Nike Free 3.0, there is probably an increased risk of injury, at least initially, when transitioning. Long term data are lacking. But, it’s also important to point out that 62% of runners who went into the Nike Free 3.0 in Ryan et al. did Nike Air Max 2017 Womens not get hurt, so it’s not the case that everyone who migrates into a Nike Air Max Tavas Damen shoe like this will suffer an injury. And, given that we don’t have a clear picture of the types of injuries suffered by the Free runners, it’s hard to know if continued heel striking and resulting increased impact loading might explain the increased injury risk.
One additional point is worth making. The Ryan study also looked at how migrating into an even more minimal shoe, the Vibram Fivefingers, affected injury rates. Though there were slightly more injuries in the Vibram group compared to those that stayed in conventional shoes, the difference was not significant. The only elevated risk was found for runners moving into the Nike Free. Interestingly, Willy et al. write the following in their discussion
