Editor’s Note: I am tickled to offer this review of the Helios SR authored by Dominick Layfield. Dominick is one of the speediest trail and ultra distance runners in Salt Lake City and Park City, Utah. Often on the podium, and with many long trail races under his belt, he prefers agile light trail runners such as Nike Terra Kiger and Montrail Rogue Fly.
|Dominick won the 2015 New Year's Day 5 Hour Run at the Utah Olympic Oval, running 39 miles!|
Dominick Layfield lives in Park City, UT, and is an avid trail runner who likes to race. He runs 10-15 races each year, mostly in the 50-100 km range. He holds a PhD in biomedical engineering from MIT, and has worked as a researcher in orthopedic biomechanics. So he knows the difference between a ligament and tendon :-).
La Sportiva Helios SR Review by Dominick Layfield
|La Sportiva Helios SR|
Putting the shoes on indoors, my first impression was how elasticated and snug the shoe feels. Due to the sock-like fully-gusseted shoe liner/tongue construction, the laces felt almost superfluous. I could run in the shoe with the laces untied.
The laces themselves are a generous length, long enough to tie knots on the end (something I like to do to avoid accidentally pulling laces through eyelets when loosening shoe), and to allow for unusual lacing arrangements. The laces are also lightly elasticated, which is helpful in keeping knots tied. This may seem like a small detail, but it’s the sort of thing that you notice when a shoe vendor gets it wrong. The tongue is generously padded, and due to the fully gusseted construction, stays perfectly in place without the need for lace loops.
La Sportiva Helios SR. Photo: La Sportiva
My second immediate impression was how shallow (height between underside of the upper and the surface of footbed) the tip of the toe-box was. I don’t have any issues with my big toes, and keep my nails closely trimmed. But if you have any damage / sensitivity in the nail of your big toe, these shoes are quite likely to aggravate it. I was aware of the lack of height and the slight contact between my big toe and the upper, and was interested to see if this caused me any discomfort. In all my test runs (approx ten trail runs, longest about 15 miles) this was not an problem.
During my first run, the shoes felt fairly stiff underfoot, almost like a shoe with a rock-plate. The amount of cushioning was really striking, given the light weight of the shoe (235g / 8.3 oz per shoe in size 10.5 US 42.5 EU, so even lighter in standard size 9.) According to La Sportiva, there is not actual rock plate per se. Instead the red top layer of the sole (the “Endurance Platform”) that you see when the blue footbed is removed is made of a denser EVA foam and intended to provide rock protection. La Sportiva describes it as follows: "It is a highly compressed EVA that is much firmer and denser than the injection EVA midsole. It is tapered and does run from 1mm thick in the heel to 3mm thick in the forefoot."
|Helios SR Cutaway- Screenshot courtesy Ultrarunning Magazine Outdoor Retailer Helios SR Preview https://www.youtube.com/watch?v=WVI9fFNpDrU|
The toe box felt somewhat narrow, which was not a surprise, since I like a wide toe box, and my previous experience with La Sportiva shoes suggested that they tend to run a little narrow, similar to Salomon shoes. However, there’s a good amount of stretch to the uppers, and the sensation of tightness disappeared quickly when running. The forefoot remains pleasantly snug, however, which makes this shoe feel agile and responsive on uneven terrain and rapid cornering, with no slippage of the foot inside the shoe.
One of my concerns with this shoe was the tread pattern and lack of grip. I’d recently run with a friend who was wearing an old pair of (the original) Helios: she was slipping sideways on the snow, and I was interested to see if I experienced the same problem. Short answer: no. For my first run, I headed out onto a snowy trail that varied in surface from slick mud to slush to firm snow and ice, depending on aspect and elevation. I figured this would be the worst possible surface for the shoe, but I didn’t have any grip problems at all: there was a little bit of sliding around in the really slippery, off-camber sections, but nothing that seemed in any way surprising or problematic.
|La Sportiva Helios SR-Outsole|
|La Sportiva Helios SR-folded without insole|
I’m not a fan of the wave-shaped sole. On the positive side, this makes the sole flexible, and arguably shaves weight. The shoe certainly has good ground feel, and has a very cushy ride on smooth surfaces. But on the other hand, the wave profile reduces protection from sharp rocks: the diminished thickness in the thinner parts of the wave means that a rock strike there hurts a lot more than when it hits in a thicker area. Not only that, but the outsole is actually cut away in these recesses, exposing the midsole and further lessening protection. During my test runs, I would find that I could run happily over most rocks, but every once in a while there would be a sharp sting that surprised me. At one point I did back-to-back 13 and 15 mile runs over dry trails with a lot of small pebbles and found that -- on the second day, particularly, with tired sore feet -- the amount of foot discomfort was becoming intolerable. This was a great disappointment as up till this point, I had been very enthusiastic about the shoe, and was planning to wear them in an upcoming 100k race.
I think the shoe would be vastly improved with a more conventional sole structure. That said, the identity of the Helios product line is in this wave-like outsole, so regrettably I don’t imagine the La Sportiva designers would contemplate this option.
To quantify how remarkably little protection there is in the areas of exposed midsole, I attempted to bend the forefoot in half and measure the double thickness with a pair of calipers [see photo]. With the footbed removed, I estimate that there’s only about 5 mm of material remaining.
|La Sportiva Helios SR-Forefoot Thickness|
|La Sportiva Helios SR-Outsole|
After a couple of runs, I found that the feel of the shoe had changed from a firmer, stiffer ride (similar to a shoe with a rock-plate) to something more soft and compliant. This might be a genuine break-in effect; it might be temperature-related (change from running in snow at 30F to dirt at 60F); it might just be my perception, an artifact of changing from a soft surface to a hard rocky surface; or a combination of these factors. When I mentioned the change in feel to Sam, he suggested that it could be related to temperature. I experimented putting a shoe in the fridge and then running with one cold shoe and one warm shoe. I was surprised at how much the temperature did affect the feel of the shoe, the cold making it much stiffer. So this might genuinely be the cause of the apparent break-in. That said, I’ve not experienced anything similar with other shoes, so I wonder if the sticky rubber used in the forefoot outsole is more temperature-dependent than more conventional outsole materials.
|La Sportiva Helios SR. Photo: La Sportiva|
Yellow Frixion XT for durability and shock absorption, Sticky black Frixion XF front
The “SR” in “Helios SR” apparently stands for ‘sticky rubber’, and refers to the black rubber (FriXion XF) that is used in the forefoot outsole. I’m not sure how I feel about this. I found the grip of the shoe to be just fine on all the surfaces I tested (snow, ice, mud, sand, packed dirt, asphalt), but I wasn’t aware of any extra traction except a little tackiness when running on warm asphalt. The sticky rubber may make this a great approach shoe for rock climbing, but I’m not convinced it is useful for running. Moreover, I worry that the forefoot lugs may wear down quickly, since this rubber is optimized for friction over durability.
The heel collar is well padded, but low. I found this slightly disconcerting. I was not used to the sensation of so little cupping of my heel, which was a little like wearing slippers. In practice, I didn’t find this to be a problem at all. Thanks to the snug fit of the rest of the shoe, I didn’t experience any heel lifting. The low heel could be a big plus if you have issues with achilles inflammation. On the other hand, if you often run through shoe-sucking mud, you might wish for a little more heel retention.
La Sportiva states that the HTT drop of the shoe is 2 mm. Whether or not this is technically correct depends on how you measure -- e.g. with foam compressed by bodyweight, including/excluding sole lugs, new shoe vs. broken-in shoe etc. However, I can say for sure that the drop feels much larger than 2 mm. I went on a test run with the Helios SR on one foot and the Montrail FluidFlex on the other, and then another run with the Nike Terra Kiger. Subjectively the Helios felt like a bigger HTT drop than either. The Terra Kiger and the FluidFlex are both nominally 4 mm drop, and based on this figure, I would say that the Helios feels more like a 6 mm drop.
I’m a textbook size 10 US in nearly all shoes. After reading a number of reports of unusual sizing in the Helios, I requested a size 10.5 for review. This was definitely the right decision. The length of the 10.5 is perfect. Any shorter and my big toe would be pressed up against the end of the shoe. Most buyers should size up similarly.
La Sportiva shoes tend to run a little on the narrow side in the forefoot, and the Helios SR is no exception. However, the uppers have a decent amount of stretch to them, and even better, there is an area which appears to be specifically designed to stretch to accommodate a range of foot widths. This area (a so-called “metatarsal window”, so I’m told) is clearly identifiable by the yellow fabric visible through the overlays.
Overall, this is a very refined trail shoe. La Sportiva’s initial sorties into running shoes were disappointing, but their current products are vastly better. The Helios SR is impeccably constructed, extremely capable on all terrain types, and provides an impressive amount of support and cushioning for an 8 oz shoe.
Unfortunately, this shoe has one big flaw. Due to the wave-like shape of the sole, there are recesses where the midsole thickness is reduced. These are also areas where the sole not protected by the harder outsole rubber. Running in sharp rocks becomes a kind of Russian Roulette: when your foot lands on a rock such that the contact point strikes a thick part of the sole, the protection is excellent; but if the rock hits one of the recesses, then the protection is minimal, and the impact is painful. What’s so upsetting about this is that La Sportiva absolutely nailed every other aspect of this shoe, which is otherwise outstanding. If only the forefoot provided more consistent rock protection, this would be an all-star shoe.
The Helios SR was provided at no charge for review purposes. The opinions herein are entirely my own.
Weight size 9/42: approx 8.1 oz 230 grams
Stack Height: Heel 21mm, Forefoot 19mm (Running Warehouse)
Midsole: MorphoDynamic Injection Molded EVA/Endurance Platform EVA Insert
Outsole Rear: Resilient Frixion XT Rubber Outsole Front: Sticky Frixion XF Rubber
Unisex sizing only
Availability: March 2015, now.Dominick is happy to answer questions via the Comments section below.
The Helios SR is available from Backcountry.com at the link below. Purchases help support my blog. Thank you!