What the research says: super shoes do not help every runner the same way

In a 2026 laboratory trial, the Salomon S/Lab Phantasm 2 improved running economy by 4.13% on average for 64 runners. Individual results ranged from 2.62% worse to 11.01% better. Athletes should try a pair in training before they rely on it in a race.

The study

Hebert-Losier and colleagues published the work in Sports Medicine Open in 2026. The title is "Exploring Factors to Explain Interindividual Responses to Running Economy in Advanced Footwear Technology Shoes: A Randomised Crossover Laboratory Trial with an Explanatory Predictor Analysis."

The trial used a randomized crossover design in a laboratory. Each runner was their own comparison. The trial had two sessions for each runner. The study reports 64 runners who completed the trial, 32 men and 32 women, aged 14.6 to 72.2 years, out of 82 recruited. Most were recreational or experienced long distance runners.

The advanced shoe was the Salomon S/Lab Phantasm 2. The control shoe was the Salomon Aero Glide 2, a regular trainer from the same company. Running economy was measured on a treadmill at 70% of each runner's vVO2peak speed. That pace was easy to moderate. It was below race pace.

A Salomon employee is a co author of the paper, and Salomon supplied the shoes. The study notes list no other funding. Readers should keep that link in mind when they weigh the findings.

Running economy is how much energy you use to hold a given pace. A lower energy cost at the same pace does not guarantee a faster race. It is still one reason these shoes matter.

You can read the paper in full here: Hebert-Losier et al., Sports Medicine Open 2026.

What they found

Across all 64 runners, the advanced shoe improved running economy by 4.13% on average, reported as plus or minus 1.6%.

Individual results covered a wide range. The smallest response was 2.62% worse in the advanced shoe. The largest was 11.01% better. Two athletes on the same roster could have very different experiences in the same model, and the group average would not tell a coach which experience either athlete had.

The researchers set 2.5% as their responder threshold. 53 of 64 runners, or 83%, were above that threshold. 11 runners were below it. At least one runner was worse in the advanced shoe, based on the low end of the range.

Who gained more from the shoe

The second part of the study asked whether the researchers could predict who would respond.

Two measures were linked to a bigger benefit. Runners with greater calf stiffness and greater navicular drop tended to gain more. Navicular drop is a static foot measure taken while standing. The correlations were r = 0.35 for calf stiffness and r = 0.31 for navicular drop.

Together, those two measures explained part of the spread between runners. The reported figure is R2 = 0.273, so most of the difference between runners remained unexplained. Calf stiffness was also the only measure that separated responders from the group below the threshold. That group difference was in medial gastrocnemius stiffness normalized to leg length, reported as Hedges g 0.86, with p = 0.046.

Most other traits did not separate responders. Age, sex, running experience, speed and prior super shoe use did not. A fast senior or a runner who already owns a plated shoe should not be assumed to be a big responder on this evidence.

These two linked measures should not be turned into a screening test. Few high school programs can measure calf stiffness in a useful way, and a static foot measure poorly predicts how the foot works while running. The predictor analysis helps explain why responses vary. It does not give coaches a practical way to sort athletes before they try a shoe.

What this means for a high school team

The age range will catch a coach's eye because teenagers were included in the sample. That needs care. Only 3 runners were under 16. The study should not be used to tell a 15 year old or a parent that a shoe will improve that athlete by 4%. The number of younger runners is too small to support that claim.

The wider finding still matters in daily coaching. When one athlete likes a racing shoe and another says it feels unstable or hard on the calves, that difference fits the pattern in the data. How comfortable the shoe feels during the run is useful information for a coach. How the legs feel the next day is useful too. Neither one is a laboratory measure.

Talk to the team in those terms. Most runners in this study cleared the responder threshold. 11 runners were below it. A workout test gives better information than the group average.

Test the shoe before race day

If an athlete plans to race in a super shoe, have them wear it in a workout first. One session can catch obvious problems with fit or control. A second session at race effort is better when the schedule allows it.

• Pick a normal workout for the first test. A controlled threshold workout works well. In StartLane zones, that is Zone 3 at 82 to 90% of max heart rate, threshold effort. Keep the workout the same as you would have run in regular shoes.
• Use the new shoe for the workout portion only. Warm up in the daily trainer if that is what the athlete usually does.
• Notice fit and control first. Look for slipping at the heel, pressure on top of the foot, toes hitting the front on downhills, or trouble holding a line on turns.
• Ask about calf soreness during the run and the next morning. Ask about the Achilles and feet too. New soreness in those spots is a reason to use the shoe less often for a while.
• Compare the session with a similar recent workout. Note whether the athlete held a similar pace at a similar heart rate and stayed in control late in the reps. Treat that comparison as a rough check. Weather can move those numbers. Sleep can too, and so can the course.

A workout test cannot measure a 4.13% change in running economy. Its job is more practical. It can catch the runner who dislikes the fit before race day. Control problems on turns show up in that same session. Check the next morning for calf soreness too. Testing in the study took place at an easy to moderate effort, so a gain there may not match 5K race pace. Athletes should wear a race shoe at close to race effort at least once before racing in it.

Limits of the study

The trial compared one advanced shoe model with one control shoe. A different racing shoe may fit better or worse, and this study cannot rank models or brands. Naming the shoe the researchers used is not a recommendation to buy it.

The work took place on a treadmill in a laboratory. Trails and grass were not part of the test. Track turns and hills were not part of it either. The test also did not cover tired late race form.

The Salomon link belongs in this section too. A Salomon employee is a co author and Salomon supplied the shoes, with no other funding listed. That connection is part of the record. It does not by itself settle whether the result is right.

Most of the spread between runners also remained unexplained. An athlete who likes a shoe for a threshold workout may still prefer a regular trainer or spikes on a muddy cross country course.

What to tell athletes and parents

The average gain was 4.13%. The range ran from 2.62% worse to 11.01% better. 83% of runners cleared a 2.5% gain, and 11 of 64 did not.

Do not promise an individual runner the average gain. Let athletes test a racing shoe in practice first. Watch how the shoe fits during that workout. Ask about soreness the next day. Keep the daily trainer as the default for most miles.

For more on fitting shoes into a normal week, see our earlier guide, Running shoe rotation: how long shoes last and when super shoes are worth it.

How StartLane handles it

StartLane does not track shoes or shoe mileage, and it does not tell you which shoe to wear. It builds 5K and 10K plans sized to your race date, from 4 to 16 weeks, with base, build and peak phases and a taper of 1 to 2 weeks. Paces are estimated from the runner's race PR and shown for each session. Coaches can use the plan to see where a threshold day falls that week. They can then decide where a shoe test fits around the other work in the plan. Keep any note about which shoe an athlete wore outside StartLane, in whatever log you already use for gear.