How To Select Your Next Pair Of Running Shoes
Prescribing Your Next Pair Of Running Shoes
Runners love a new pair of running shoes. However there is a lot of confusion around which shoe or shoes are best for you. The decision on which pair to buy next can be influenced by the large amount of information out there (evidence based or not), shoe company marketing campaigns, friends or family recommendations, health professional recommendations, personal preferences, shoe appearance or features and much more. Let’s dive into how to go about selecting your next shoe.
It’s NOT All About The Shoe
Health professionals working with runners will be the first to tell you that the shoe isn’t the most important thing for any runner. There are bigger ticket items that all runners need to be aware of such as training load (volume, intensity), recovery, form and technique and strength and conditioning. To date no clear evidence exists that any particular shoe will prevent injury for a specific runner (1-6).
There are currently 5 high quality research studies which demonstrates that traditional shoe prescription does not prevent running related injuries in runners (1, 2) or in the military population (4, 5). Another recent study has found that runners with a more pronated foot type who were in a motion control shoe had some protection against injury (6). So currently prescribing footwear based on foot type to prevent injury; or shifting shoes to try to prevent injury doesn’t have solid evidence.
If someone wants to change shoes, such as from a more rigid supportive shoe to a more minimalist shoe this is completely ok, yet you should be aware of how to transition safely and know there is no clear practical evidence linking the transition to the new shoe (no matter what the shoe) to a reduced risk of injury. The transition to a new shoe also carries an increased injury risk, particularly towards a more minimalist shoe, without an appropriate transition period, amount of education and strength and conditioning (7).
There are many cases where a runner will swap into a new pair of shoes and their pain has gone away or conversely try a new pair of shoes that feel good in store, go for a run and all of a sudden have pain or injury. This leads the runner to love or hate these new shoes and label them as either ‘fixing’ or ‘causing’ a problem. This creates a sea of confusion on the internet labelling shoes as being the cause or fix of someones plantar fascia pain or knee pain. Why this occurs is a complex question, explained most simply by the notion that the shoe is a tool for ‘load modification’.
Changing shoes can be a way of subtly changing how loads are distributed in the foot and further up the body. This can be enough to either overload a tissue with low capacity leading to pain or shift load to a more robust tissue leading to reduced pain or symptoms. The new shoe can also alter a runners form or cadence which can also then alter the distribution of loads and changing pain. Who this happens for and who this doesn’t happen for is variable but there are some trends that are apparent (these are explored in ‘Shoe Prescription for the Injured Runner’ below). So before we go into prescription understand that we aren’t trying to prevent injury, as there is no evidence that we currently can.
Shoe Prescription for the Un-injured Runner
Not injured but wanting a new pair of shoes? There has been a lot of research looking at how to find the right pair of shoes for a runner. These include trying to match the runners foot to a shoe based on amount of pronation, foot types and foot posture, based on plantar shape and numerous other variables. None have shown compelling evidence that support it can reduce injury. So just because your foot has a certain posture doesn’t mean you need a certain shoe. So what do we base it on? (8-10).
- Comfort, evidence has suggested that comfort is a good predictor of how well a shoe will suit a runner. Comfort isn’t king and isn’t the panacea for running shoes, however it may be comfortable as it suits the foots natural movement path. It’s often tough to know how comfortable a shoe is until you’ve run in it a few times. Here is where having a good local running shoe retailer helps, who let you run (on treadmill or road) with the shoe a couple of times before returning it if it’s not ‘comfortable.’
- Where performance is a priority consider a lighter shoe. A lighter shoe has been linked to better running economy however you need to consider which aspects of the shoe are changing as you move lighter (11). These may include large changes in drop, stack height, motion control technology and longitudinal flexibility.
- Keep it similar. If you are looking to keep things the same, choosing a shoe that is similar to your previous shoe is smart, this ensures that there is not a large deviation from what your feet and anatomy are used to. Loads may be distributed similar and there will be less time needed to adapt to a shoe. A great tool for this is the Minimalist Index.
- Use the ‘Minimalist Index.’ There is a fair chance you haven’t heard of this yet, but you’ve probably heard of ‘minimalist shoes.’ The Minimalist Index has been developed by an international panel of experts to provide a definition for the quantity of minimalism each shoe has. It is a valid and reliable tool that can tell you the percentage of minimalism using important variables including; flexibility, weight, heel-to-toe drop, stack height and stability or motion control technologies . So for example a vibram five fingers is 96% and a Nike Zoom Structure is 20% of the Minimalist Index. This isn’t a scale of good or bad, but a scale that can be used to compare shoes and identify shoes that are similar or closely related to your current pair. This becomes really important to identify if a longer period of transition may be needed from your old shoe to your next shoe. For more information on the Minimalist Index, a database of shoes and how to calculate it can be found HERE. Recommendations of important note include, aiming for 1 month of transition time for every 10-20% change in the Minimalist Index score. For instance, you should plan a 1-2-month transition period when switching from one pair of shoes rated 50% to another pair of shoes rated 70% (12).
- Focus on non shoe related items (load, sleep, nutrition, S&C)
- Consider prior injury history (see the next section)
Shoe Prescription for the Injured Runner (Current or Previous)
When assisting a currently or previously injured runner towards their next pair of running shoes we still keep in mind all the same things mentioned above for the Un-Injured runner. Where the considerations broaden are in the potential role a shoe can play as a tool to offload or change load. There is the ability to ‘change’ loading through a number of different variables (all of which are included in the Minimalist Index above) – ie flexibility, drop, stack height and motion control technologies.
Changing shoes can benefit or aggravate certain problems. Moving towards a shoe with a higher percentage of minimalism or a lower drop increases Achilles tendon forces (13) and thus may aggravate an Achilles Tendinopathy in the short term. Whilst conversely moving away from more minimalist shoes towards a maximalist shoe or a cushioned shoe with a higher drop can ‘shift’ some load from the calf and Achilles and increase patellofemoral joint forces (14). As higher patellofemoral joint forces has been linked to injury, more minimalist shoes then may benefit some runners with patellofemoral pain (14, 15).
Conversely, for some individuals with knee pain, shifting to a maximalist shoe can increase patellofemoral force and thus increase an already sore knee. It is worth noting that this hasn’t been well researched and one hypothesis is the reduced ‘proprioception’ of a maximalist shoe, ‘hides’ overstriding, which is known to be a running technique risk factor for knee pain and injury. A recent study for example found that over a 6 week transition to a maximalist running shoe for rear foot strikers, there was an increase in vertical ground reaction forces (this has been previously linked with injury, although there is some contention as to whether high external forces equate to higher internal forces- a blog for another time)(16).
Again this study only assessed forces and not injury occurrence. So in the short term a maximalist shoe MAY benefit some runners with Achilles or calf pain, while a more minimalist shoe MAY be helpful for knee pain.
The use of motion control technology or previously termed ‘anti-pronation shoes,’ may be suggested in cases where pain occurs with movement into pronation. For many people this includes plantar heel pain, medial ankle and shin pain and various other foot pathologies. Again the idea is that by shifting load off some of the medial structures may make a significant change in symptoms. There is of course contention in the literature as to whether putting someone in a motion control (anti-pronation) shoe actually does reduce pronation, however regardless of what happens biomechanically for some people it can change symptoms. A trial of taping to attempt to mimic the support of the shoe can give clues as to whether this may help someone.
All shoe recommendations, modifications or changes are done in the background on a focus on monitoring and modifying running and jumping loads, use of strength and conditioning and other specific individual factors. Injuries sustained in the past when wearing particular footwear will also influence decision making, yet again load variables will be considered. So having a stress fracture in a minimalist shoe doesn’t mean you shouldn’t buy another minimalist shoe, it might mean your running loads jumped up too quickly and it would have happened no matter what shoe was on your feet.
If you’ve made it this far you’ll know that it is complex! You can’t prevent injury with certain footwear choices, yet you might feel better in a particular shoe or number of shoes. It’s highly individual, and a matter of careful load monitoring, listening to your body and gradual adaptation. To declare my bias, I own and run in shoes from 20 to 85% on the minimalist Index, so don’t advocate any particular shoe brand or type of shoe.
Lewis Craig (APAM)
Masters of Physiotherapy
Featured in the Top 50 Physical Therapy Blog