The last several years have seen a dramatic change in the looks and design of A Part of Hearst Digital Media. As maximal shoe design continues to influence the industry, a majority of shoes are seeing large increases in sole height and bending stiffness and increasing usage of plates. In addition to thicker, stiffer, and plated shoes, you may have noticed an increase in the frequency of another rarely discussed but important component of many running shoes, a large upward curve right under the toes.
This feature is called toe spring. With it becoming increasingly prevalent, it’s worth knowing why it exists, and whether shoes with a lot of toe spring might help or hurt your running.
High toe spring in the Asics Noosa Tri 13 due to a thick and stiff sole, find it with Runner’s World+
The What and Why of Toe Spring
Toe spring refers to the degree of upward curvature of the sole under the toes or forefoot (front of the foot). Its purpose is to facilitate forward motion through the front of the shoe.
During normal gait mechanics, as your weight transfers over the front of your foot, the metatarsophalangeal (MTP) joints, or toe joints, extend. This allows the heel to rise and the body to roll over the front of the foot. Called the forefoot rocker, this is a particularly important mechanism of the foot that contributes to efficient forward motion.
For the forefoot rocker to work appropriately, the MTP joints need to be able to move a certain amount (i.e., number of degrees) to allow this forward-rolling motion. If you have less than 60 degrees of upward motion (called extension), you may have some difficulty using the natural mechanism.
There are two reasons to include toe spring in a shoe. The first is if the person has a dysfunction of the forefoot rocker. A variety of reasons can lead to limited motion at the MTP joints including arthritis and hallux limitus or rigidus (stiff and painful conditions of the big toe joint). If someone doesn’t have enough motion there, transitioning over that area may be difficult or painful. Toe spring replaces this mechanism of the foot, allowing the body to transition over the forefoot without the need for as much motion at the toes.
The second reason is if the sole of the shoe isn’t flexible enough in the forefoot to bend and allow motion in this area. This is the major reason for the increase in toe spring frequency and degree that we’re seeing now. Thicker soled shoes, often seen in maximal shoes, are often less flexible, meaning that transitioning over the front of the shoe can be difficult. Flex grooves, which are grooves cut into the sole to improve flexibility, are often not enough to allow for flexibility in some of these shoes. To allow for forward motion, toe spring is utilized to allow motion over the forefoot. The thicker the sole, often the sharper the curve or greater degrees of toe spring are needed to allow the foot to roll forward.
To expand on the second reason, an increasing number of shoes, both for training and racing, have plates in them. A plate, particularly a carbon-fiber plate, will also stiffen the sole. This usually allows very little motion at the forefoot. For the body to appropriately transition over the front of the shoe, these plated shoes also need a significant amount of toe spring. If not, whether the shoe sole is thick, has a plate or both, it may feel like trying to run over a speed bump.
Shoes With Toe Spring
saucony Endorphin Pro
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Low toe spring in the Saucony Kinvara 12 due to a very flexible forefoot
Who Is Toe Spring Good For?
Again, toe spring is increasingly prevalent in running shoes to compensate for thicker and stiffer soles. This design feature could be especially helpful for runners who have pathology at their toes or the front of their foot, or limited motion at their ankle joints. Toe spring is usually the front half of a rockered shoe, which also adds a curved heel to the overall picture. These shoe types have been found to reduce load and force on the Achilles tendon, forefoot, toe joints and foot/ankle overall. For those with problems in these areas, some may find some relief and ability to continue running/walking.
For runners without problems at the front of their feet, toe spring may sound great, who wouldn’t like more forward propulsion? As with everything else, toe spring can come with a catch. You can’t just eliminate the forces your body absorbs when you run; they have to go somewhere. Maximal and rockered shoes, (i.e., those with a lot of toe spring) have been found to reduce forces and work at the ankle/foot, but may increase these in the knee and hip joints.
Also, as a doctor of physical therapy who works with a large population of runners, my clinical experience has been that those who have weaker hip muscles and This increasingly prevalent feature can helpor hurtyour running can sometimes report difficulty running in rockered shoes or shoes with toe spring. This may be because the mechanism shifts work away from the areas where they have better strength.
Additionally, not all toe spring is created equal. Some versions allow for the toes to be kept in a neutral (flat) position while the sole curves up underneath. Other shoes have toe spring that is aggressive enough that the toes are held in an upward position (extension). If you don’t have enough motion at your toe joints, the second version is likely going to cause you more problems than it will fix! There are also arguments that excessive toe spring causes weakness of the intrinsic foot muscles, but at this point has yet to be proven by high quality research. If that is a concern for you, wear a variety of types of running shoes with and without toe spring.
Tests for Toe Spring
There are a few important ranges of motion I usually look for when determining whether someone might benefit from a shoe with toe spring. The first is whether the person has enough big toe extension (upward curve of the toes), which should at minimum be 60 degrees. The second is whether that person has enough dorsiflexion (bending your ankle to bring your toes toward your shin, which should be around 15-20 degrees. There are two easy at-home tests you can do to assess yourself in these motions.
Great Toe Extension Examination: Place your foot flat on the floor and seeing how far you can actively lift your big toe. Then take your fingers and see how much further you can passively bend it at the big joint. Halfway between flat and straight up is 45 degrees, so you should be able to get a little beyond that at least passively by pulling. If not, a shoe with toe spring may be beneficial for you.
Weight-Bearing Lunge Test: This test has been found to be valid and reliable for looking at ankle dorsiflexion. Line one foot up facing the wall and while in a lunge position keeping your foot flat on the ground, see how far forward your knee can move. You can try this first with your toes barely touching the wall; the bare minimum is that your kneecap should be able to touch the wall without too much trouble. If you can, start moving your foot back until the distance between your longest toe and the wall is 1 to 2 inches. This equates to approximately 15-20 degrees of ankle dorsiflexion.
If you have great difficulty with either of those tests and can’t achieve the minimum, a shoe with toe spring may be helpful for you. This may help maintain the forward roll over the front of your foot during running as you may be having trouble with appropriate motion in your ankle or toes. For those with muscle or joint stiffness, while a shoe with toe spring may be helpful, you should be working to improve motion in these areas. If you have pathology in this area that may not improve, shoes with appropriately designed toe spring may help you continue running and walking.
If you run occasionally in shoes with large amount of toe spring (like the many special-foam, plated super shoes), there are a few things to keep in mind. As with anything new, you should transition slowly into these types of shoes. Given that toe spring changes where forces may be absorbed in the body, your body needs time to get used to this. Injuries occur most commonly when doing things too quickly and excessively. Transitioning slowly into these types of shoes means running only a couple miles in shoes with a great deal of toe spring first to let your body acclimate. Then, as you’re comfortable, slowly increase the miles and intensity.
For those who like a more natural and flexible shoe, shoes with toe spring may be something you want to avoid. Fortunately, there’s enough variety in running footwear today that there’s something for everyone.
The bottom line is that toe spring is a component of many types of shoes and should be thought of as a tool. Some people will find the tool useful, while others may not. Each person will have different preferences in running shoes, so it’s up to you to experiment and see what works best for you.
Matthew Klein is a doctor of physical therapy in practice in Monrovia, California, and the founder of the Doctors of Running sport science and shoe review site.
