This topic is an exciting one. The science of human biomechanics continues to advance and the footwear industry keeps evolving. I’ve been looking forward to this year’s update and wanted to share some observations and suggestions.
Running shoe research and development drives much of the athletic, hiking, walking, and casual shoe markets. So, even if you don’t consider yourself a runner, this information may be quite useful. I’ve organized this piece into some brief responses to commonly asked “what are” questions.
What are the primary considerations in selecting an ideal shoe? Probably the most important thing shoes do for us is to provide some level of protection for our feet. If we only lived and trained on sandy beaches or manicured grass fields, in warm climates, we would have very little need for shoes. Beyond the protection they provide, shoes can also improve our traction. They can help to prevent foot and leg fatigue in many circumstances. And they may possibly contribute to energy return, or a propulsive assist, in each push off in the gait cycle.
What are some of the basics with regard to achieving optimal fit in a shoe? While this may seem obvious, shoes that have a natural foot shape, and that mimic your own individual foot dimensions, will work best. The upper should have an instep slope that sweeps upward from the toes toward the ankle at an angle that is similar to that of your own foot. Getting this right will help the shoe to conform to your whole foot and hold it snugly without applying too much compression to sensitive blood vessels and nerves on the top of your foot. The outsole should generally be narrower at the heel than at the forefoot. And the insole, when you take it out of the shoe and stand on it alone, should not be obliterated from view with your foot spilling too far over its edges. The toe box should have a width and height that gives your toes a bit of wiggle room. This allows the forefoot to splay under weight-bearing and helps to prevent blisters. And having a thumbnail’s space (or slightly less) between the big toe and the end of the shoe will minimize the risk of bruised toenails. Last but not least (pun intended), the last or shape that the shoe is built upon, should have a straight or curved form just like your foot. There are lasts made for women’s and men’s feet, and most are brand-specific. No features in the shoe will do you much good until you find one that fits well, and this is largely a journey of trial and error, plus a little research.
What are some of the current trends in shoe design and construction? Uppers continue to get thinner and lighter for the most part, with newer synthetic materials that breathe well, don’t get waterlogged, and offer stretch/no-stretch options. Midsoles have moved away from some (but not all) of the gadgetry of times gone by such as air, gel, mesh, and the like. Most shoe companies are using high grade versions of ethylene vinyl acetate (EVA foam) and now the trend in higher-end shoes is to use elastomeric polymers like Pebax. Light, springy, and long-lasting is the trend. Heel counters are going away in many shoes. Outsoles continue to use high-carbon rubber for its unsurpassed durability, but most modern shoes use less of it, employing thinner, strategically-placed amounts in high wear areas. For the most part, gone are the tractor-tire outsoles of old.
What are the general categories of running shoes? We still see many of the major manufacturers offering their shoe lines with specific orthopedic needs or usages in mind. Neutral shoes are those that attempt to encourage or at least not overly limit natural foot motion. Cushioned shoes have thick midsoles. Stability and motion control shoes still exist, but their “anti-pronation” features have morphed a bit, emphasizing the support of contoured midsoles and rocker designs. Trail shoes offer more traction and protection from rocks. And racing shoes for the track, cross-country course, roads, or trails provide that light, fast feel in pared-down versions of their parent designs.
What are some of the latest trends in running shoe styles? Probably the most interesting progression is possibly a regression or return to prior design concerning midsole thickness. For years there was the moderate thickness midsole that gave way to the minimalist or thin midsole models in the early 2000’s. Then the maximalist movement took over and the thick, chunky shoes were all the rage. Thin and thick shoes still exist but the latest trend is moving back toward a more moderate overall midsole height in the shoes, brought about largely by the newer midsole material innovations. Board lasts, or internal fiberboards, have given way to primarily stitched, or slip-lasted uppers. And shoes are still getting lighter, pushing the average weight envelope even lower. One gripe a lot of runners and athletes in general will state is that all this refinement has come at a sacrifice in durability, with shoes not lasting quite as long as some would wish.
What are the latest trends around heel-to-forefoot differentials? We are still finding shoes available in roughly three approximate configurations. Zero drop models having no difference in height from heel to forefoot, are still around and are loved by those who feel it promotes a very natural movement pattern. Large-differential shoes, having 10-12mm height differences, are currently very popular in road running and racing. Advocates suggest they save energy by bringing the ground up to meet to the foot (so to speak) so a forefoot striker does not have to “set” the heel down. Critics suggest this will encourage heel striking in other runners. And, as you would imagine, a middle ground series of shoes can be found with differentials of 4-6mm. You really have to try all these shoes to see how each works for, or against, your personal biomechanics.
What are the some of the features of the carbon plates embedded in certain shoe midsoles? The carbon fiber flex-plate has been a source of popularity and controversy. The theory is that as the plate is loaded when the forefoot flexes, it then springs back and assists propulsion as we toe off. Individual runner weight and speed, as well as style may require “tuning” of the plate to offer this potential advantage. Whether it enhances performance, for everyone, and to what degree, remains a debate, but we are sure to see this technology pervade into not just most running shoe brands but many other footwear styles as well.
What are some of the thoughts about shoes either encouraging more foot “work” or reducing it? This is a great question that speaks to what happens when one wears a minimalist, zero-drop shoe versus a high stack height, large differential shoe. Essentially, the lesser shoe provides the opportunity for more foot and leg strengthening, but at a cost of more musculotendinous work and oxygen consumption (possibly, according to some studies). On the contrary, the more “supportive” shoe may decrease the work demands and allow a runner to go faster or farther, or both, in race and key workout conditions. Common sense says you might want that advantage on race day but for long term health keeping it more natural for most training might be best.
What are the common opinions about shoe selection for training in the gym? Many of the characteristics mentioned above can apply for general gym training, but for the two major anti-gravity lifts (squat and deadlift) you may appreciate decidedly different shoe designs. The descent of a squat utilizes an inhalation and plantarflexion bias (more on this in another missive) and elevated heels are generally preferred/helpful for squatting. This is why you typically see competitive weightlifters wearing them in Olympic lifting and squatting situations. Conversely, the deadlift utilizes the hinge pattern which is extension and exhalation dominant. Having the feet flat on the floor can help to drive this movement pattern. Again, this is why you see many deadlifters training in Chuck Taylors or even socks.
And finally, what are a few things to keep in mind with shoes for court and field sports and multidirectional training? Lateral stability and surface. Shoes designed for cutting and changing direction need to be built to withstand lateral forces, and not place the foot too high off the ground in order to avoid ankle sprains. Surface comes into play when we are considering the total amount of energy return involved. Concrete, such as on a “hard” tennis court (not clay or grass) demands more cushioning. A football cleat for playing on grass, will be very hard to complement the soft natural terrain. Trying to move effectively on any soccer, rugby, or related field in thick, soft shoes will feel wonky at best and downright unstable at worst. And as you would imagine, basketball and volleyball courts are somewhere in between with their shoe demands. Fortunately, all this is built into the designs of such shoes, but the aforementioned fit considerations still apply.
I started out trying to be brief, but this diatribe got away from me a bit. As you can see, I think the shoe selection game is fascinating, and I’ve got a lot to say about it. If you’d like to really learn more about making the best choices in footwear for your health and performance…and get some of your questions answered directly…join me for the MasterClass on the topic Wednesday 5/20 at noon (registration open til Tuesday at noon), or reserve an exclusive class for your team, club, or business. Stay healthy, stay fit…and as always…stay Hard to Kill!