Hip flexion for minimising knee loads
A very interesting paper from Gatti et al. has demonstrated that the minimum hip flexion seems to be associated with knee loads. This means that, cyclists who present excessive flexion of their hips at the top of the stroke are more likely to present larger knee loads. The reason for this relationship is because knee loads, particularly patellofemoral forces are larger when then knee is close to maximum flexion. As this is observed when maximum hip flexion is observed, it is not surprised they both joints contribute to the overall flexion of the lower limb. Implications from this finding are multiple. The primary is that, saddle position should be determined in order to ensure that excessive knee flexion is minimised, as this will increase knee forces and possibly increase the likelihood of knee pain and injuries. In addition, ankle movement can contribute to larger hip and knee flexions, particularly when excessive plantar flexion is observed. However, a clearer implication of cycling for many weeks an months with large hip and knee flexion on the development of knee pain is still to be determined. Until we get further evidence on this space, it is worthwhile keeping an eye on hip and knee flexion of cyclists in order to ensure that large flexion of these joints are not observed.