This was timely. I was just working on the lesson for my Clinical Biomechanics Boot Camp course about the Preferred Motion Pathway and a new publication turns up on it. As Hannibal Smith from the A-Team used to say “I love it when a plan comes together“; or for my daughter’s generation, as Special Agent Oso used to say, “It’s all part of the plan, more or less“.
The Preferred Motion Pathway was a model that was first proposed by Benno Nigg and stated simply as our body or musculoskeletal system has a preferred pathway or any given movement. The role of an intervention (footwear, orthotics, gait retraining) is to support the system in its preferred pathway. If that is achieved then muscle activity is reduced and supports a more economical way of running. If the intervention opposes the preferred pathway, then muscle activity is increased resulting in more fatigue and less economical running. The assumption that comes from this is that the correct prescription of an intervention must support that preferred pathway of the individual, which is likely to be subject specific. This model is the basis of the Run Signature concept from Brooks, though the study below was funded by Mizuno.
This was the publication:
The Preferred Movement Path Paradigm: Influence of Running Shoes on Joint Movement.
Nigg, Benno M.; Vieneau, Jordyn; Smith, Aimée C.; Trudeau, Mathieu B.; Mohr, Maurice; Nigg, Sandro R.
Medicine & Science in Sports & Exercise: March 8, 2017
Purpose: (a) to quantify differences in lower extremity joint kinematics for groups of runners subjected to different running footwear conditions, and (b) to quantify differences in lower extremity joint kinematics on an individual basis for runners subjected to different running footwear conditions.
Methods: Three-dimensional ankle and knee joint kinematics were collected for 35 heel-toe runners when wearing three different running shoes and when running barefoot. Absolute mean differences in ankle and knee joint kinematics were computed between running shoe conditions. The percentage of individual runners who displayed differences below a 2[degrees], 3[degrees] and 5[degrees] threshold were also calculated.
Results: The results indicate that the mean kinematics of the ankle and knee joints were similar between running shoe conditions. Aside from ankle dorsi-flexion and knee flexion, the percentage of runners maintaining their movement path between running shoes (i.e. less than 3[degrees]) was in the order of magnitude of about 80 to 100%. Many runners showed ankle and knee joint kinematics that differed between a conventional running shoe and barefoot by more than 3[degrees], especially for ankle dorsiflexion and knee flexion
Conclusion: Many runners stay in the same movement path (the preferred movement path) when running in various different footwear conditions. The percentage of runners maintaining their preferred movement path depends on the magnitude of the change introduced by the footwear condition.
Nothing in the methods jumps out at me as being problematic. The 3 shoes used were Mizuno Be, Mizuno Wave Rider and Mizuno Wave Universe which each has quite distinct design features.
Essentially what they showed was that there were no or minimal systematic differences in knee and ankle joint kinematics between the 3 running shoe conditions, but as the authors noted, there was likely to be individual increases and decreases in parameters measured (ie subject specific response) so that the mean response were none or minimal (ie systematic response). Without going into the detail (they are in the full publication) they showed that many individual runners did stay in the same pathway despite the changes in the footwear condition. The percent of runners that appear to stay in their preferred pathway changes, depending on the magnitude of the change in the footwear condition, which was greatest when comparing the Wave Rider to barefoot and least when comparing the Be to the Universe. A strength of the way the results are presented in this study is that the authors reported the results based on several different thresholds of change which readers can interpret their own way depending on their own philosophy of what is an important degree change in the parameters investigated.
What this study adds to our understanding is the emphasis that the change in footwear condition in some runners does not change their preferred pathway and in other runners it does. I have lost count how many times I have used the word ‘subject specific’ in different posts I have written!
As always, I go where the evidence takes me until convinced otherwise …. and this preferred motion pathway model explains a lot.
Nigg BM, Vienneau J, Smith AC, Trudeau MB, Mohr M, & Nigg SR (2017). The Preferred Movement Path Paradigm: Influence of Running Shoes on Joint Movement. Medicine and science in sports and exercise PMID: 28277405