Relevant Gems from the 2015 Footwear Biomechanics Symposium

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The Footwear Biomechanics group of the International Society of Biomechanics meets every two years; right now its meeting in Liverpool, UK, so here are some of the relevant selected highlights from this meeting for me:

Darren Stefanyshyn started of the meeting with his keynote on Footwear Research: Where do we go from here? The take home message for me was his emphasis on the need to take lab based biomechanical research through to the field or clinic to see if the interventions actually do work to achieve the outcomes that is assumed or speculated from the lab based mechanical studies. He proposed an interesting model in which footwear characteristics could be applied to injury (ie traction, mass, torsion, bending stiffness, insole texture, cushioning, posting, etc) can then get mapped onto different athletic activities in relationship to performance and injury.

Sharon Dixon et al reported on her study: Influence of increased shoe lateral stiffness on running biomechanics in older females. They tested a specially designed New Balance shoe with different stiffnesses in the sole (ie to simulate “lateral wedging”) and investigated the relationship to knee abduction moment (ie the main risk factor for knee osteoarthritis). They found no systematic changes, but then went and eliminated some people from the data who demonstrated an adductor moment at midstance. The results showed that the shoe did decrease the abductor moment in those who had an abductor moment (if that makes sense?).

To allow for growth most parents buy shoes too big for kids to allow for growth. Is that a problem? Kobayashi et al investigated “How do too big shoes affect to the joint kinematcs of kids gait pattern?” and found that as shoe size increased there was a decreased stride length and decreased walking speed; minimum toe clearance increased, so they concluded: “We found that wearing shoes that are oversized negatively impacted gait parameters“. On a similar theme, Ueda et al reported that wearing running shoes that were too long increased the loading rate during running.

I always harp on about how different running techniques and different running shoes affect different runners differently and many of the studies presented at the conference fit nicely into that mantra. One of these was from Jonathan Sinclair et al on the Influence of barefoot and shod running on limb and joint stiffness characteristics during running which pretty much showed that there was higher knee joint stiffness in barefoot condition compared to barefoot inspired shoes and conventional running shoes; and that ankle joint stiffness was higher in the conventional running shoes compare to the barefoot conditions (six of one and half a dozen of the other).

Trudeau et al used a sophisticated statistical technique to analyse plantar pressure data in a group of runners looking for any patterns that could make up distinct groups. They were able to identify two quite distinct groups. There were big age differences in the two groups (37yrs vs 26yrs) which may explain the differences, perhaps due to age related changes in tissue properties or muscle strength. The author did show two videos of the distinct patterns and my observation of them was there there was less first metatarsal head loading in the older age group pattern. One way I (not the authors) could interpret that is that this may represent Bojsen-Mollors high gear (transverse axis) vs low gear (oblique axis) propulsion (I discussed that theory here).

Baltich et al reported on the The influence of ankle strength exercise training on running injury risk factors in which 129 runners were randomized to one of 3 groups: functional strengthening (lunges, squats, hopping, jumps); resistance strengthening (TheraBand) and a control group (stretching). The study was powered to look at changes in muscle strength (which they found) and was not powered to look at injury rates, which they did anyway and what they found was interesting:
– the functional group had 62 injuries/1000hrs running
– the resistance group had 41.7 injuries/1000hrs running
– the Stretching group had 58.7 injuries/1000hrs running
Not all the running injuries were “time loss injuries”; there were 4 that were and all 4 were in the functional training group and all those 4 were in the foot.

Chris Bishop et al reported on his Prelim investigation of the immediate effects of footwear and custom foot orthotics on the foot in patients with plantar fasciitis. 10 subjects with plantar fasciitis were assessed in 3 conditions: barefoot; Asics Gel Nimbus; Custom orthotics + Nimbus. The design of the custom orthotics and its prescription was based on a focus group with podiatrists. The orthotic group reported the most comfort and less pain. Kinematically the orthotics reduced eversion; increased inversion moment; and increased peak TMT dorsiflexion (~higher arch height). However the response was variable with the response in some favoring the shoe condition and some favoring the orthotic condition. There is a need to explore why. Also the biomechanical effects were small and is that enough for a clinical effect?

Deneweth et al looked at Individual-specific determinants of successful adaptation to minimal and maximal running shoes with the aim of the study being to determine the extent to which a simple clinical test can predict successful adoption of minimalist or maximalist running shoes. 36 rearfoot strikers; strength testing VO2 max and foot stiffness measures; ran in Altra The One; Altra Paradigm and New Balance Minimus for baseline testing, then randomized to one of the 3 shoes. During 4 weeks there were no injuries in the maximal shoe group and 10 mild injuries and 4 serious injuries in minimalist group (the 4 had to leave the study). They concluded that:
– The early results suggest that maximal shoes do not require as large a gait modification as minimal shoes
– Foot posture and stiffness metrics do not appear relevant to predict response
– Minimal and maximal adaptions appear to be individually specific

Kersting et al looked at the effects of different drops. They used a ECCO minimalist running shoe with 3 inserts to change drop: 14mm drop; flat (no drop); and a negative 5mm drop. They found no systematic differences in EMG parameters and found a systematic change in ankle dorsiflexion – (dorsiflexion > in negative drop > flat > 14mm drop). However, 5 of 15 did not follow systematic pattern in ankle kinematics, so they took those 5 out of the dataset and redid it and found the remaining 10 had reduced variability and the negative drop showing greater EMG activity of tibialis anterior than flat which was greater than 14mm drop. They concluded that “It was confirmed that individual adaptations dictate how athletes may respond to footwear modification which potentially alter the energy storage and return processes with the biological system without adding any energy return capacities within footwear“. This is what I argued here on the evidence for zero drop and that the drop is very subject specific with each individual runner appearing to have a ‘sweet spot’ for the amount of drop that is most suitable for them.

I saved the best to last: This one is going to put a spanner in the works, so much so I will write a separate post devoted to the details of the study. Malisoux et al did a prospective blinded randomized controlled trial of motion control shoes vs neutral shoe and got less injuries in the motion control group. Watch this space. {EDIT: here it is}

This was not close to being all that was presented and discussed at this conference. I and Ian Griffiths (thanks Ian) did live updates from the conference here and the whole abstract book is here, as a supplement to Footwear Science.

I enjoyed being in Liverpool and it was great to catch up with all the colleagues from around the world involved in running and running shoe research to chew things over with. The next one is on the Gold Coast in Australia in 2017.

As always: I go where the evidence takes me until convinced otherwise, and there was some good evidence presented at this meeting.

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3 Responses to Relevant Gems from the 2015 Footwear Biomechanics Symposium

  1. Eric August 15, 2015 at 8:15 pm #

    Hi Craig,
    I can’t find the references above in pubmed. Can you provide more info about the references so i can find them? (i.e. journal, etc). Or am I just missing where the references are listed? Thanks!
    Eric

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