Article by Dom Layfield
Introduction
Let me start by saying that this article describes my personal opinion. What works for one runner might not be a good match for another. And I am sadly unable to test all the zero drop shoes in the world. That said, I’ve run a fair few miles on trail, and a good fraction of those have been in zero-drop and low-drop shoes. I think I’m pretty well qualified.
I should also perhaps say a little about my personal opinion about heel-to-toe drop in running shoes. I don’t think that zero-drop represents some biomechanical ideal that we should all aspire to. Moreover, while it might sound simple, it’s not clear what ‘zero-drop’ even means. If a running shoe is rockered (i.e. the sole thickness is not uniform from front to back) then how does one determine whether it is zero-drop? Should one evaluate sole thickness in relaxed, unweighted state, or when compressed by bodyweight? When the shoe is worn, or after it has been broken in? RTR Editor Sam swears that some “zero-drop” shoes feel as if they do have a small amount of drop, and I think I know what he means. Certainly, I have squeezed many shoes which didn’t feel entirely flat, and even used calipers to check .
On the other hand, I’m pretty convinced that higher HTT drops (>6 mm) are undesirable, and regard shoe brands that continue to make >10 mm drop shoes as dinosaurs unwilling to modernize. Even there, though, the waters are muddy. A brand may intend to make flatter shoes, but cannot ignore feedback from its established customer base that wants new shoes to feel just like the old ones. Then there is the trend in plated road shoes, pioneered by Nike with the VaporFly 4%, and copied and iterated upon by others, which generally have higher drops intended to improve efficiency. For the most part, these seem only to be useful on the smoothest of surfaces. The VF4%, for example, is terrifyingly unstable on trail, and any straightline performance gain is vastly outweighed by the challenge of remaining on your feet. In regard to the latter, the only trail shoe I’ve encountered that incorporates such technologies is the pioneering Skechers Speed TRL, which is a more modest 4 mm nominal drop.
One important aspect of zero- and low-drop shoes is that they encourage mid- to forefoot striking. Whether this is ‘better’ or not, in terms of long-term injury prevention or running efficiency remains controversial. My personal belief is that every trail runner should be comfortable doing both, as the terrain will dictate which is optimal. This opinion is reinforced by the fact that (arguably) the greatest mountain runner of all time does not consistently do one or the other.
Tester Profile
Dom 48, trains and competes mainly on trails in Southern California running on average about 3000 miles and 500k ft of vert per year. In 2017 he was 14th at Western States 100 and in 2018 finished 50th at UTMB and 32nd at the 2018 Los Angeles marathon in a time of 2:46. 2019 was a quiet year, with his only notable finish at the multi-day Dragon Back race in the UK.
The Contenders
Since the premise of this article is “zero-drop”, I’m going to exclude even those shoes that are slight drop, for example, the Topo MT-3 is nominally 3 mm, and Hoka Speedgoat series are 4 mm.
The 800-lb gorilla in the zero-drop world (particularly trail shoes) is, of course, Altra. All of their shoes are, and always have been, zero-drop. Of their line-up I have not tested the super-sized Olympus. But I have tested, and raced in, multiple generations of all of their other trail shoes.
Altra:
Superior 4.5
Lone Peak 4.5
Timp 2
King MT 2.0
The next player in the zero-drop space is Topo, with the excellent Runventure 3. Topo make many other shoes that are low-drop, but as far as I am aware the Runventure 3 is Topo’s only officially zero-drop model
Topo:
Runventure 3
UK-based trail shoe pioneer, Inov-8, also make a zero-drop shoe. The recently reviewed TerraUltra G 270 drew rave reviews from the RTR team. In view of this latest entry, we figured a zero-drop trail shoe showdown was due.
Inov-8:
Terra Ultra G 270
Individual Descriptions
Altra Superior 4.5 (510/560 g) [RTR review]
This is the lightest, softest shoe from Altra (510/565 g per pair, size US M10, without/with removable rockplate). The latest version is a remarkable shoe, with a spectacular, innovative slipper-like upper. In keeping with previous iterations, the Superior comes with a removable rockplate (“Stoneguard”). Without the insert, the shoe feels distinctly minimal, and offers about as little rock protection as I’m personally comfortable with. Purists may not consider this a true ‘barefoot’ shoe, but it’s pretty close. Weakness of the shoe? Because it is so soft and flexible, it really doesn’t seem an obvious match for long distances, and grip is only okay.
Altra King MT 2.0 (584 g) [RTR review]
The King MT is ostensibly optimized for muddy terrain and OCR. A velcro strap across the forefoot and directional sharkskin fabric keep the shoe glued to your feet. The ride is firmer than the squishier Superior 4.5 and slightly lower to the ground. A little heavier (584 g per pair) than the Superior, the King provides amazing grip, and great trail feel. Personally, this shoe fits my foot impeccably. The limited cushioning makes this not an obvious choice for ultradistance efforts (although I’ve seen them used at slip-n’-slide events like the HURT-100), and they are definitely more at home on softer ground than on road. They are also perhaps not as friendly to heel-strikers as other shoes.
Altra Lone Peak 4.5 (630 g) [RTR review]
The Lone Peak is a standout among the shoes in the review in terms of forefoot width. Altra shoes have traditionally been very wide in the forefoot, but in recent years, many models have become a little narrower with a more moderate width. That has given the shoes more mainstream appeal but alienated some Altra devotees. The LP4.5 maintains the generous forefoot of old-school Altras, so if you have hobbit feet, this is your best choice. This is also an attraction if you are engaged in epic adventures that may involve considerable foot swelling. The LP is a popular choice among Appalachian Trail through-hikers. The downside of the extra room is that it becomes harder to stop the forefoot from sliding around, and several RTR reviewers were underwhelmed by the foothold in the LP. Personally, I dinged the LP4.5 for its disappointing protection-to-weight ratio: at 630 g per pair, it is not a heavy shoe, but it is a full 100 g heavier than Superior 4.5, and doesn’t provide noticeably more protection or cushion. It is 38 g heavier than the more-cushioned, more protective Timp 2.0 On the other hand, it offers excellent grip and durability, and does just about everything well.
Altra Timp 2.0 (580 g) [RTR review]
Did I mention that newer Altras are less roomy than older versions? The Timp 2.0 is an excellent example of this. If you read reviews of this shoe around the web, the majority of negative reviews come from owners of previous versions who are upset that Altra changed the fit of their favorite shoe. For my perspective, the change is a clear improvement. I liked the old shoe, but I was over the moon about version 2.0. There are few shoes out there that just feel so right on my feet, like they were made-to-measure. Compared to the Lone Peak, the Timp provides significantly more cushioning, more rock protection, and better foot retention. Downsides? The really big one is the lack of durability. I’m on my second pair after the first literally fell apart at the seams. The Timp upper fabric gets abraded by trail grit and really needs a rand to protect the sole join. However, a workaround that I’m currently testing is a DIY rand created by smearing ShoeGoo/Aquaseal around the perimeter.
Topo Runventure 3 (522 g) [RTR review]
The Runventure 3 is Topo’s lightest trail shoe, and only zero-drop model. There’s not much to see here. No flashy bells and whistles, just a lightweight, flexible shoe that can do everything and go anywhere. A moderately wide forefoot and excellent foothold combine with a small but sufficient amount of cushioning and an unobtrusive rockplate that doesn’t compromise trail feel. It’s hard to put into words why exactly this shoe is so excellent, but it surprises me with its ‘just rightness’ every time I put it on. Downsides: upper fabric a little crinkly; not enough protection for long days.
Inov-8 Terra Ultra G 270 (552 g) [RTR review]
I previously reviewed the TUG260, and felt that its considerable strengths were undermined by its lack of cushioning and protection. While it might excel in mud, the ride was harsh and unforgiving on hard, rocky surfaces. The newer TUG270 retains all of the high points of its predecessor, but is both lighter and more cushioned. The TUG270 is not perfect (I personally preferred the slightly wider forefoot and snugger midfoot of the TUG260), but it is utterly excellent, hitting the sweet spot across the board with no weaknesses. In terms of bang-per-gram, this is a really impressive shoe: light enough to race, secure enough to race, comfortable enough to use every day for training. The only downside I can think of is that at $160, it is expensive.
Conclusions
As ever, there’s no simple answer. The ‘best’ shoe depends on who you are, and what you want the shoe to do.
For everyday training, I have a hard time choosing between the Altra Superior 4.5, the Altra King MT 2.0, and the Topo Runventure 3. These are at the more minimalist end of typical trail shoes, and all are outstanding. If you spend a lot of time in muddy terrain, the King MT is a clear winner. If you like an extra-flexible, slipper-like feel, go with the Superior (which also has a removable rockplate that enables you to fine-tune the shoe to taste). For simple, understated excellence, opt for Runventure.
For higher-volume training, ultra-distance racing, or if you just like lots of cushion, the Altra Timp 2 is an excellent shoe. My only concern is the durability of the upper (see note above for suggested remedy until Altra release 2.5 update).
For a one-shoe-quiver, the Inov-8 TUG270 is hard to fault. It has enough cushion for (fairly) high mileage, and performs impeccably on all terrain and in all conditions. I would wear this shoe both for daily training and to race at distances up to 100 km.
The only ugly duckling here is Altra’s Lone Peak, which -- unless your feet are super-wide -- doesn’t really have a compelling scenario where it outperforms the competition. While it used to occupy a middle ground in Altra’s line-up, it now seems outclassed by better, lighter shoes from above (Timp) and below (Superior). With the arrival of the Inov-8 TUG270, it makes even less sense. I’m hoping that Altra have something spectacular lined up for version 5.
9 comments:
This is the content I'm here for. Excellent write-up Dom! I often miss the cult-like adulation for the zero-drop designs of 2010 through 2015. I adore zero-drop and minimal shoes as these both resolved some long-term ITBS and feel more *fun* and less *plodding* to me as a runner.
And if I can add one thought to the biomechanical discussion, it's is this. I think there's a reasonable case to be made that the eccentric gastroc and soleus contraction at footstrike in a minimal shoe (needed to "catch" the body's weight rather than relying on artificial cushion) *might* be more cardiovascularly efficient. The hypothesis here is that greater lower limb muscular contraction in this initial phase of the gait cycle would return more blood from the lower extremities via muscular venous return. I first noticed this years ago when I noticed that running in high drop shoes felt effortful and resulted in higher heart rates than minimal and zero-drop designs. I'd be curious to try and develop an experiment to test this, but it'd be challenging to measure venous return in a person at motion.
Anyway. Love the Superior 4.5!
Thank you. A really interesting read. Are there reasons why zero drop is particularly popular in trail running?
@Curt,
As always, I appreciate the kind words and insightful remarks.
What you say about venous return is interesting. I've never thought about that before. One might expect from a mechanical point of view that increased contraction of lower leg muscles ought to consume moreenergy. What's surprising is that this is not observed in laboratory studies. (Which show no significant strike-dependent difference in efficiency.) The mechanism that you postulate (assisted venous return) may offset the cost of increased contraction.
That said, after running for a while, the system is going to reach steady state. Blood flow into the leg must equal blood flow out of the leg. And hypoxic vasodilation of the leg arterioles should regulate total blood supply to match flow with metabolic demand. So the upside to the 'assisted' venous return would be in lessening the cardiac load: i.e. your heart would have to work less hard to pump the same amount of blood.
However, as I'm sure you're aware, what you have personally observed (that you are more efficient in zero-drop shoes) is not born out by experiment. My recollection is that runners were just most efficient when running in shoes that are similar to what they are accustomed to wearing.
-- Dom
@Mike
Good question. I've not thought this through carefully, but I'll attempt an answer.
As Nike have demonstrated with VF4% et al, it is definitely possible to design a shoe that measurably increases running efficiency. These shoes are thick-soled, rockered, plated, and incorporate a significant heel-to-toe drop. However, the efficiency gains only manifest when running on a smooth, flat, hard surface. If the surface is irregular, inclined, soft, etc, then the slight efficiency gains of the shoe will be more than offset by the many downsides.
A race car designed for the asphalt track is not going to perform in an off-road race. The optimizations that enable a track car to gain an edge in performance on road (e.g. low front spoiler, stiff low-travel suspension) may be disadvantageous on a rough surface, and one might expect similar differences between road and trail shoes that make heel-to-toe drop (and other road optimizations) either moot or tangibly worse. On steep uphills, everyone lands on their forefoot, so the heel stack is dead weight. On downhills, a heel-to-toe drop tends to make forward sliding of your foot inside the shoe worse. On rough and off-camber terrain, it makes the shoe more likely to tip and sprain your ankle.
-- Dom
@Dom,
Yep, I think your concluding thought (in that we are most efficient in the shoe/style in which we've become accustomed) is the most likely one. But nonetheless... wouldn't it be neat if we could monitor cardiac preload (or potentially iliac vein diameter) in a runner at motion? I certainly wouldn't put money down on this hypothesis bearing any kind of fruit, but I think it's an interesting thing to think about nonetheless. Which is why I think the "zero-drop and minimalist shoes are more fun" argument is ultimately the strongest one on the topic. But... personal taste.
Regardless! I certainly enjoy the content and discussion here. Stay safe all!
@Mike: one might add regarding the advantages of zero drop on the trails, that it reduces the risk to twist your angle, as you have better ground control, especially, because the midsole tends to be thinner too as shock absorption does not play such a prominent role on soft ground as is does on the road.
I have the TU270’s after years away from Inov-8 and love them. I think it’s remarkable that the shoe with that stack height is not overly firm yet protective (without a rock plate nonetheless). I also find it to be very versatile, both in terrain and distance, which I highly value in a trail shoe with the varied terrain and distances I run. I also like that it’s light for a trail shoe.
Thanks both for your replies.
Altra Lone Peak 5.0 will be updated with a full length EGO midsole. Should be very nice.
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