Choosing a shoe depends on the conditions under which you run and your gait type. The Sir Isaac Guidance Trainer (M/W) models are a fantastic shoe for the runner who is looking to be a midfoot runner, but who also needs a little more coaching to achieve the midfoot foot strike.  The outsole offers greater ground coverage, the lugs are beveled on the front third, and the entire outsole is layered with carbon rubber for better durability against friction.  

Our Performance Trainer (M/W) and Light Weight Performance Trainer (M/W) models are identical in the forefoot and differ only in the weight and the construction of the heel.  They are both high mileage shoes. The Light Weight Trainer heel is made of exposed EVA foam, and the shoes are best worn by exclusively midfoot runners. The Performance Trainer heel is layered with rubber on the outsole for better durability, and they offer better wear for runners who are learning to run more midfoot. 

If you're already running with a more efficient midfoot strike, we suggest you start out with our Performance Trainer (M/W) – if you're farther back on the heel, then you may be better off with our Guidance Trainer (M/W).

Many people find they wear a ½ size larger in Newton Running shoes than in traditional running shoes.

Please check the sizing chart on our website.

While comfort is key, there are additional factors to keep in mind when fitting Newton Running shoes:

• Flex point/arch length: The joint of your big toe should fit approximately in the middle of the flex panel on the inside of the shoe. This places the flex point of your foot, where your toes bend up, over the four external lugs on the bottom of the shoe.
• Width: Your foot should not spill over the sides of the shoe when you stand and put weight on the ball of your foot. Remember your foot spreads and swells as you run. Your running shoe is likely to be larger than your dress shoe, possibly up to a full size larger.
• Length: You need at least ¼ inch of room between the end of your longest toe and the inside of the end of the shoe, preferably more. This can be up to a full inch if you have a very long arch and/or very short toes.
• Volume: You should be able to comfortably lace your shoes.

The ball of your foot should be positioned over the center of the four external lugs on the bottom of the shoe. Learn more about how to your running shoes should fit.

 There are literally hundreds of ways to lace shoes based on specific needs. Here are a few common methods:

• If your laces frequently come untied, we recommend the surgeon's knot (also known as the orienteering knot). This works well on round laces and for racing when you absolutely don't want the lace to come loose. Much better than a double bow, this knot is easy to tie (once you learn it) and simple to undo.
• If your laces are too long, trim them or try one of the many lacing methods that shorten the ends.
• If your laces are too short or if you feel pressure in a particular location, you can skip a hole or two, or try one of he many lacing methods that lengthen the ends. 
• If your heel slips or if you move forward in the shoe, utilize the double eyelet with a lace lock.

Universal posting is denser, more supportive midsole foam located along the medial (inside) and lateral (outside) edges of the shoe. This runs from just forward of the heel to the ball of the foot and reduces late stage pronation and late stage supination. Late stage pronation/supination is the foot's propensity to roll in or out as you load the ball of your foot.

Because of its posting on both the medial and lateral sides, Universal posting also accommodates a neutral gait type.

Yes. Newton Running shoes work well with orthotics, although we strongly recommend you use only flexible orthotics that balance your forefoot. Rigid rear foot orthotics are known to decondition the structure and tissues in your foot (weakening it) and are not generally designed for running.

Active Imprints, available from the Newton Running Lab, are the running orthotics of choice and are used by dozens ofelite and  World Champion athletes. Drop in or call the Newton Running Lab at:

Newton Running Lab
1300 Walnut St. Suite 20
Boulder, CO 80302
Tuesday - Friday 10a-6p
Saturday 10a-4p
303-494-0321/877-865-9572

Yes. The Guidance Trainer (M/W) is available in both medium and 2E widths. The Performance line (M/W) is a medium width.

It is unlikely you are too heavy for Newton Running Shoes.  The technology used in all Newton Running shoes works like a trampoline – when your foot strikes the ground, the raised lugs on the outsole compress through a stretch membrane into a hollow chamber in the midsole.  In independent testing, Newton Running shoes show test superior in cushioning, shock absorption, and energy return regardless of size.

If you are currently running with a heavier heel strike, we encourage you to modify your gait to a more natural running stride. In this case, you may find our Guidance Trainers (M/W) the best in terms of fit and function.

Consider sizing both shoes for the largest foot. If you have a very large discrepancy and can’t run in the larger shoes on your smaller foot, then you may need to buy two pairs of shoes.

Choosing a shoe depends on the conditions under which you run and your gait type. The Sir Isaac Guidance Trainer (M/W) models are a fantastic shoe for the runner who is looking to be a midfoot runner, but who also needs a little more coaching to achieve the midfoot foot strike.  The outsole offers greater ground coverage, the lugs are beveled on the front third, and the entire outsole is layered with carbon rubber for better durability against friction.  

Our Performance Trainer (M/W) and Light Weight Performance Trainer (M/W) models are identical in the forefoot and differ only in the weight and the construction of the heel.  They are both high mileage shoes. The Light Weight Performance Trainer heel is made of exposed EVA foam, and the shoes are best worn by exclusively midfoot runners. The Trainer heel is layered with rubber on the outsole for better durability, and they offer better wear for runners who are learning to run more midfoot. 

If you're already running with a more efficient midfoot strike, we suggest you start out with our Performance Trainer (M/W) – if you're farther back on the heel, then you may be better off with our Guidance Trainer (M/W).

Choosing a shoe depends on the conditions under which you run and your gait type. The Sir Isaac Guidance Trainer (M/W) models are a fantastic shoe for the runner who is looking to be a midfoot runner, but who also needs a little more coaching to achieve the midfoot foot strike.  The outsole offers greater ground coverage, the lugs are beveled on the front third, and the entire outsole is layered with carbon rubber for better durability against friction.  

Our Performance Trainer (M/W) and Performance Light Weight Trainer (M/W) models are identical in the forefoot and differ only in the weight and the construction of the heel.  They are both high mileage shoes. The Light Weight Trainer heel is made of exposed EVA foam, and the shoes are best worn by exclusively midfoot runners. The Trainer heel is layered with rubber on the outsole for better durability, and they offer better wear for runners who are learning to run more midfoot. 

If you're already running with a more efficient midfoot strike, we suggest you start out with our Performance Trainer (M/W) – if you're farther back on the heel, then you may be better off with our Guidance Trainer (M/W).