Earlier this fall, I declared that as much as I love running barefoot, or using minimalist footwear like Vibram’s FiveFingers, when it comes time to train for ultras again, I would probably go back to using standard trail shoes. I mentioned that some companies have embraced the minimalist concept, combining super-lightweight designs with basic protective features to allow maximal freedom of movement, natural biomechanics and ground feel, and improved overall comfort.
The primary shoes I had in mind were the New Balance MT100.
Even before its release, the MT100 was causing quite a stir in the ultra community, primarily because of its two high-profile design contributors: Anton Krupicka and Kyle Skaggs (be sure to watch the cool video on that link for your daily dose of mojo), both of whom have already become legends of the sport at a very young age. 26-year-old Krupicka holds numerous course records and is a two-time winner of the Leadville 100, while 24-year-old Skaggs did what many ultrarunners considered unthinkable: breaking the 24-hour mark at the Hardrock 100, widely considered the most challenging 100-miler in the world.
Krupicka in particular is famous for his minimalist approach to running. One of his mantras is a “return to simplicity”, and he’s generally seen running without a watch, hydration pack, shirt, or even shoes - many of his 200 training miles per week are done in bare feet, even on high mountain trails. Both he and Skaggs have been known to carve large chunks of material away from their training shoes to eliminate any excess weight or bulk that would hinder natural movement. Obviously, New Balance couldn’t have found two more ideal people to create a minimalist shoe that could hold up to the demands of rugged long-distance trail running.
For the most part, they succeeded. The MT100 weighs in at a superlight 7.8oz, with a very low profile and fantastic ground feel, as well as a handful of features to bolster its overall durability. The only component I found somewhat lacking was comfort in a couple of specific areas, as I’ll explain shortly. But first, a rundown of the shoe itself.
The MT100 isn’t offically an update of New Balance’s popular 790 lightweight trail runners - coincidentally, the same model that Skaggs wore for his Hardrock record - but given that this shoe was introduced at roughly the same time that the 790 was discontinued, many runners view it as the next generation 790. Like that shoe, the MT100 features New Balance’s RL-3 racing last which is designed to be narrow through the heel and wide through the forefoot – in other words, ideal for runners accustomed to going barefoot.
From that starting point, Krupicka and Skaggs spent countless hours and hundreds of miles in New Balance’s sports testing lab, using all sorts of biomechanic devices like force plates and motion capture sensors (the little lights they strap all over pro athletes to make computer-generated facsimiles for video games). The design team looked at contact and transition points of the midsole and outsole, and identified high-wear areas that needed extra reinforcement. They also gathered feedback from the two runners on stripping the shoe down to its bare essentials while preserving a bit of comfort for the long haul.
The most notable adaptations are on the shoe’s upper, which is little more than a thin synthetic mesh with strategically placed EVA to maintain shape. The tongue is relatively short, and is simply a thin piece of fabric, which could cause potential top of foot discomfort if you lace them up too tightly - but I never had a problem with this. New Balance’s “sausage link laces” (officially known as SureLace) are quite effective at keeping the upper snug without too much pressure. A puncture-resistant wrap in front of the toe box provides a bit of protection from sneaky roots or rocks that might take you by surprise.
In addition to slicing weight, the overall effect of this fabric-cutting on the upper is that the shoe is extremely well ventilated; in fact, this is probably the most well-ventilated shoes I’ve tested aside from the Newton Gravity, which has mesh holes so large you can almost stick your finger through them. Fortunately, the mesh of the MT100 is closed enough to prevent most debris from getting in – although I still notice some fine sand particles getting through to my toes like when I wear my FiveFinger KSOs. As with the Vibrams, this amount of dust isn’t nearly enough to bother me.
Behind the shoe, the mesh is supported by a lightweight EVA material that extends into the shoe collar. Since there’s no fabric on this EVA collar to absorb sweat, the inner surface was made especially smooth to decrease friction and prevent blisters. However, this is the area where I’ve had the most discomfort, as the collar feels too rigid against my Achilles tendon. I broke the shoes in with several 4-6 mile runs where this wasn’t an issue, but once I started stretching my distances out to 10 or 15 miles, I developed a very sharp “biting” pain behind my ankle. Even with about 100 total miles on the shoes, this ankle bite is aggravating. Clearly, my tendons must not be as tough as Krupicka’s or Skaggs’s.
The other comfort issue I noticed was the overall size of the uppers, particularly in the length. On steep downhills, my toes contacted the front of the toe box, eventually causing some pressure points after multiple miles. This is probably a sizing issue as opposed to a structural one; normally I go up a half-size with my trail shoes compared to road trainers, which gives me ample room in the box for steep descents. If I were testing a second pair of MT100s, I’d probably go up a full size instead of just a half.
Beneath the upper, the MT100 gives you just enough padding to make the ride comfortable, but not so much to eliminate the feel of the ground underfoot. The midfoot is built very low to the ground, with heights of 18mm in the heel and 8mm in the forefoot. New Balance uses ACTEVA® midsole cushioning which resists compression and is 12% lighter than standard foam, thus helping to keep the overall weight of the shoe low.
The MT100 utilizes New Balance’s Rock Stop technology, a thin rigid plastic layer between the outsole and the midsole that disperses the force of sharp rocks or other penetrating objects across the entire plate to diminish the overall impact pressure at any particular location. For barefoot runners, the most telling feature of this shoe’s design is that Rock Stop support is provided in the midfoot area, but not the heel – thus promoting a midfoot or forefoot running stride in the same manner you do without shoes.
Barefoot running mechanics are also evident in the tread pattern of the outsole - specifically, the heel area is relatively minimal and smooth, with reversed lugs for braking. This makes sense for midfoot runners, as the only time they land on their heels is when trying to maintain some control while going downhill. Likewise, the midfoot area of the outsole is given the most reinforcement, with higher profile knobs for multi-directional grip. Keeping with the lightweight theme, even the outsole is involved, as you can see scooped-out areas underneath the arch in an effort to eliminate as much unnecessary material as possible.
Overall, aside from a couple of comfort issues that might hopefully be addressed in future versions, there’s a lot to celebrate about the MT100. It’s clearly a forerunner in the emerging category of minimalist trail shoes, and New Balance’s collaboration with two of the best ultrarunners in the world demonstrates its commitment to maintain high performance standards while striving to be as lightweight as possible. They’ve embraced the biomechanical benefits of barefoot running and provided a very solid option for minimalist (i.e. Vibram FiveFingers users like me) runners who want a bit more toughness and durability when taking on ultra distances or extremely difficult terrain. All this, and it's completely affordable as well (see pricing below). If more companies follow New Balance’s lead in these regards, that would be very good news indeed.
The New Balance MT100 retails for $75 from the company website, with several discount prices available via Google search. The best price I found is $50 from FinishLine.com (search "New Balance 100").