La Sportiva Helios SR ReviewApril 30, 2015
- Extremely soft and comfortable
- Excellent responsiveness and turnover
- Sticky outsole rubber grips well on rock
- Poor traction on gravel and scree
- Limited protection underfoot
- Upper breathes and drains poorly
The La Sportiva Helios SR achieves a remarkable combination of cushioning, responsiveness, handling, and turnover. However, the lack of underfoot protection makes this shoe best suited for smooth surfaces.
The La Sportiva Helios SR is a trail shoe that seems to defy conventional logic. Both the upper materials and midsole foam have a level of softness and flexibility that almost feels therapeutic on the foot. During testing, it even remained comfortable during 3-4 hour runs. Most shoes that feel this soft tend to be mushy and unresponsive, however the Helios responds nicely to fast running on flat terrain. This responsiveness results in a shoe that can handle a variety of speeds and distances. On climbs the Helios is less responsive due to energy loss, caused by a lack of stiffness. The shoe’s traction is generally excellent except on steep, graveled surfaces.
The major challenges with the Helios are its lack of underfoot protection and marginal stability on highly technical terrain. Because the midsole is so soft, push through protection is almost non-existent. Therefore this is not a shoe for rocky trails unless speeds are quite low. Another consequence of the soft midsole is reduced stability during hard, aggressive cornering. There simply isn’t enough rigidity to keep the foot from perpetual movement after the shoe contacts the ground.
The Helios will appeal to runners looking for a versatile, daily trainer to use on groomed trail and other smooth surfaces. It is not the best choice for heavier runners or those doing significant miles on rugged terrain.
The comfort of the Helios is one of its stand-out characteristics. The upper material is soft and flexible, and the padded tongue helps to lessen lace pressure over the top of the foot. Underneath, the mid and outsole materials are both soft without being mushy. In testing, sometimes the shoe felt over-compressed during fast running on hard surfaces—rock and pavement—but this did not seem to be an issue on trail. There are a couple of drawbacks to the Helios: the thick upper material breathes and drains poorly, and because the shoe is so soft, it offers very little push-through protection against rocks.
Speed & Agility
The Helios is a much faster running shoe than the cushioning suggests. The midsole material offers a surprising amount of response at higher speeds, and the lighter weight assists both turnover and foot placement. Although the heel-to-toe drop is fairly low, the Helios actually runs like it has a more aggressive profile.
Security of Fit
The overall softness of the Helios makes a secure fit somewhat hard to achieve. The upper material lacks the stiffness necessary to resist rotational motion. This is compounded by the softness of the footbed, which compresses out from beneath the foot and thereby allows separation between the top of the foot and the upper of the shoe. These issues were most noticeable on highly technical trail however, the security of fit was more than adequate for groomed single track.
Heeluxe, our shoe testing laboratory partner, tests the responsiveness of a shoe by measuring how thick a running shoe is and multiplying it by how much pressure the forefoot foot feels while running. The softer or thicker the midsole, the less responsive a shoe will feel, but the more comfortable the shoe will generally feel. The thinner or firmer a midsole is, the more power you’ll feel at toe-off.
The Helios took a little getting used to on technical trail due to the characteristics of the midsole material, specifically the tendency of the shoe to exhibit uneven medial-lateral compression during hard cornering. The low-profile forefoot and wider ground contact area mitigated this issue, producing reasonable stability.
Over the course of a few weeks, our wear-test team does multiple runs in each pair of shoes they test. They aim for a variety of runs (easy recovery runs, long training runs, harder race-pace efforts) across as many different types of trails as they can manage. The team is spread across the country, so we are able to test under a variety of different conditions, terrains, and types of trail, from gently-rolling fire roads to highly technical mountain singletrack.