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Newton Terra Momentus

By Tom Demerly


Newton Terra Momentus Guidance Trail Running Shoe
Newton's new Terra Momentus Trail shoe may make some conventional trail shoes feel like a dinosaur...

Few running shoe companies can boast technology that dates back to the 1600’s, the era of Newton’s name sake, Sir Isaac Newton. Newton Running is founded on Newton’s third law: for every action there is an equal and opposite reaction. Think of a gun firing: The bullet discharges, the gun recoils. The bullet goes forward, the gun jumps back and up. In running, your foot hits the ground with significant force- the energy goes… where? With Newton the shoe hits the ground; the impact forces are re-vectored into forward movement via their patented sole technology. Energy can neither be destroyed nor created, only transformed into other forms of energy. How does Newton manage this impact energy? How is it transformed- converted- stored? Does it really work?

Newton claims their shoes use “Action/Reaction” patented technology to direct the flow of foot impact into forward motion through energy storage. They return that energy through use of a “lever” and “spring” of sorts over which the foot pivots during running. This technology is included on Newton’s new Terra Momentus, the first dedicated off road shoe from Newton.

Does it work? I say emphatically “Yes”.

And, while I am convinced that Newton’s unique sole configuration does result in measurably faster running, there are additional benefits to the Newton sole design in an off-road setting.

Newton Terra Momentus Guidance Trail Running Shoe
The heart of the Newton technology: The energy storing, converting and returning "actuators"- the red lugs and hollow spaces above them- as seen in this midsole cut across its width.

The cornerstone of the Newton design is the four vaguely rectangular boxes under the ball of your foot: the actuators under the metatarsals. If you cut a pair of Newtons width wise (we did) you see how they collapse under footstrike and rebound during push off. The additional benefit in a trail setting, where you are running on irregular surfaces, is the segregation of the actuators provides the only truly independent suspension and shock absorption in a trail shoe. A rock strike under the sole doesn’t affect the entire shoe sole, only the area of impact absorbs (and rebounds) the energy. Additionally, the suspension is uni-directional: it works along the length and width of the shoe.
We may have evolved to run barefoot, but we’ve further evolved (or de-evolved) to need shoes for protection. Add to that an ingenious way to partially store and return footstrike energy for forward motion and the Newton shoe is a real world segue way between the physics of barefoot running and the realities and limitations of the everyman anatomy- combined with the need for protection.

Newton Terra Momentus Guidance Trail Running Shoe
Popular running literature suggests that a "barefoot" running style creates different foot geometry with the ground- with the forefoot oriented lower at foot-strike than the heel-leading style shown on the left. This forefoot or "barefoot" running style is claimed to require less energy, produce less impact and be more efficient. Newton shoes mimic this geometry but with the protection of a running shoe.

This reviewer was an early Newton adopter. I bought my first pair when they originally became available. Proving to myself the shoe worked took an inadvertent mistake- an example of learning through error. I bought a size too large. The actuators weren’t placed correctly under my foot – they didn’t work as designed and were quite unremarkable. I visited the Newton booth during Ford Ironman Wisconsin where I mentioned my experience. They promptly re-fit me for shoes- revealing my original purchase was a full size too large, and went on to replace the shoes with the correct size, one full size smaller.

The results were instant and measureable. At the same heart rate range I was between 15 and 20 seconds faster per mile. That is worth re-reading and I did verify it was accurate. I know of no other performance running product that can instantly produce these measureable results. My previous run pace at 160-170 BPM heart rate was a rather pedestrian 8:10-8:40 per mile depending on conditions- usually to the low end of that range. My Garmin heart monitor/GPS consistently showed sub 170 BPM readings at 7:50 to 8:10 pace in the Newtons. The shoes tested faster immediately. This trend of generally faster per-mile pace at a consistent relative effort continued. It was the elusive golden bullet. Free speed- well, at least speed without additional effort.

“At the same heart rate range I was between 15 and 20 seconds faster per mile.

 There is no such thing as a free lunch however and I, in my new found high(er) speed exuberance ran fast and hard in my Newtons every day. Until my calves started hurting. Bad. I ignored the Newton acclimation period that recommends gradual use of the shoe at first. It was just too much fun to be faster all at once. A trifle hamstrung I meekly returned to conventional shoes- and my more pedestrian pace. Until now. I’m back to occasional Newton use.

Newton Terra Momentus Guidance Trail Running Shoe
These photos show the forefoot-high bias of the Terra Momentus, forcing the running forward on the shoe for a more forefoot interaction.

This reviewer will tell you Newtons are faster. Ford Ironman World Championship winner and Newton athlete Craig Alexander might suggest the same. But like anything faster- a disk wheel on your bike, a can of Red Bull before a workout, it works best when used with moderation- especially at first during the Newton-described “acclimation period”.
The Newton Terra Momentus is the first foray into off-road shoes for Newton. It is a refreshing slant on a trail shoe as it deviates significantly from other trail offerings that are effectively lightweight, low top hiking shoes. This is not a lightweight speed hiker, it is a running tool.

Newton Terra Momentus Guidance Trail Running Shoe
Designed and adapted from on-road Newtons, the new Newton Terra Momentus has a tread pattern and outsole that provides better traction on trails, sand and dirt/loose rock than the road shoe.

The upper is tightly woven, shark-skin ballistic fabric that won’t allow dust and sand to enter the shoes. Our test shoes were tortured in a desert environment with no debris entry. The first three lacing eyelets have an anti-debris gaiter sewn under them- a fine detail. The laces themselves feature a miniature ridge that makes accidental untying rare. A lime green synthetic “rand” or heel/midsole armor plate starts at the ball of the foot and wraps around the heel. This fortifies the upper and provides noticeable stability while tuning up the responsive foot-handling of the shoe: It goes where you want it.

Newton Terra Momentus Guidance Trail Running Shoe
The Men's Terra Momentus features a catchy, "lizard green" color way.

There are typical layers of polymer material to prevent excessive roll in the midsole- and they work- along with various durometer EVA to absorb shock. This part of the shoe follows a conventional theme. The patented Newton actuators interrupt that theme and add the unique Newton running capability and a pleasant surprise: These shoes have independent suspension across their width. You don’t feel bumps underfoot and the entire sole of the shoe does not deform over small obstacles such as a rock- only the part that needs to moves, keeping the shoe level and sure-footed. This improves up hill traction and ride quality. Aggressive lugs that provide braking power aren’t as necessary, although our primary tester did report “thrilling” descents in the Newtons and would have liked better braking on descents. Other companies such as GoLite have taken a similar approach by using aggressive lugging to isolate the feeling of stepping on pointed rocks but only Newton helps store and return energy this way. The result is a smooth, stable, snappy ride even on rocky, sharp terrain. For the dedicated trail runner this may be one of the most tangible benefits.

Newton Terra Momentus Guidance Trail Running Shoe
Undiscovered benefit: On uneven and rocky terrain the independent suspension benefit of having seperate lugs provides shock absroption, stability and reduces ankle strain.


Our primary tester, Retail Manager Erik Jacobsen, reported greatly decreased impact in the Newton Terra Momentus. Footstrike, especially uphill, was greatly moderated. Erik rated the toe box fit as “excellent and accurate”. While ascending was above average our man Erik, a veteran of multiple off-road ultras, did say descending in the Newton needs your undivided attention. He reported little traction in the heel- not surprising since the emphasis on this shoe is forefoot foot strike. The word “skiing” was mentioned several times. Erik’s experience extended to over 50 miles of trail use including runs on Mt. Lemmon’s Red Ridge Trail, a 3 hour run in Molina Basin and two ascents to the Seven Falls up Bear Canyon. Erik also put in about 15 miles on the road in this shoe.

Newton Terra Momentus Guidance Trail Running Shoe
Left: Newton Terra Momentus after three runs (I washed the shoe sole for the photo). Right: Same shoe after 50-60 miles combined trail and road running. The leading edge of the actuators- the four "treads" or blocks on the bottom of the shoes- wears down to facilitate your stride. Once they wear to a workable level, the wear decelerates and the shoes are broken in to your individual stride length and geometry.

In the course of testing we sometimes discover a few things worth pointing out. For Erik, the midsole foam on the medial side of the heel tore and abraded rather quickly. In future versions a “wrap” of heavy wearing carbon rubber over this area would prolong shoe appearance- we’ll see if Newton notices. The fragmented EVA isn’t structural, but does make it look like the shoe is awfully torn up after 50-70 miles. If you don’t do rocky descents this won’t happen.

Newton Terra Momentus Guidance Trail Running Shoe
Our tester did experience "chipping" of the midsole from rocky off road terrain. This area of softer EVA may need covering by carbon rubber to increase cosmetic durability.

Wear on the actuators (the 4 forefoot lugs) is normal, especially on abrasive surfaces and at the leading edge of the actuators. It may actually help “tune” the shoes for better push-off. Once they wear in, with the leading edge of the lugs grinding down rather quickly, they seem to stay that way and not wear further. This is mostly a feature of the shoe breaking in.
The shoe is a competitive 12.9 ounces per foot in a size 10.5 on our scale. Compared to other trail shoes like popular “The North Face” Ultra 105 GTX XCR the Newton is lighter by over 2 ounces (reported 15 ounces for The North Face shoe). Some trail shoes are lighter, like Salomon’s Speedcross and Inov-8’s Roclite 312 GTX, but these shoes do not provide the energy return and performance of the Newton Terra Momentus.

Newton Terra Momentus Guidance Trail Running Shoe
Left: The women's version of the Terra Momentus is light blue. Right: Our test shoes tipped the scale at a moderate to light 12.9 ounces in a size 10.

In general the Newton “Land, Lever, Lift” philosophy and the patented actuators are tangibly unique. I will tell you it makes you faster and have experienced it myself. I wager you will have a similar experience. As a trail shoe the Newton Terra Momentus is a very unique entry- more so than most in that it is actually a running shoe, not a light adventure/hiking shoe. Additionally, the “independent suspension” effect of the actuators on rocky surfaces moderates gnarly terrain with luxurious ride. Finally, nice details in the upper show that Newton is a company attendant to details and in touch with what a runner needs in the real world- on road and off.
This shoe is a credible offering with unique features and benefits. It is a worthy inclusion in any trail running shoe wardrobe

Newton Terra Momentus Guidance Trail Running Shoe
Combining unique Newton patented sole technology with a nicely made, off-road specific upper the Newton Terra Momentus is a valid trail running entry with all the energy return benefits of a Newton shoe.