Our verdict

The La Sportiva Mutant stands out as a fierce trail running shoe, built for stability on technical terrain. In our tests, we found it excels in the wildest runs. However, its performance dips on easier terrains, so it's more of a specialised, high-drop tool in your rotation rather than the ultimate do-it-all trail shoe. Its specific design is matched with a unique, eye-catching look that's bound to split opinions among everyone. And while it's not the lightest option out there, we believe that its rugged construction and exceptional grip make it a formidable choice for those challenging, technical trails.

Pros

  • Exceptional fit for narrow feet
  • Extremely durable upper
  • Outstanding stability
  • Great breathability
  • Customizable lockdown
  • Head-turning design
  • Fairly priced

Cons

  • Unquestionably heavy
  • Potential for rapid outsole wear
  • Excessively firm midsole

Audience verdict

87
Great!

Who should buy

We award the La Sportiva Mutant a stellar 5-star rating for:

  • Trail runners eager to conquer technical terrain who aren't concerned about the weight of their shoes.
  • Those seeking a high heel-to-toe drop paired with a firm midsole for trail adventures.
  • Runners looking for a visually striking trail shoe that offers superb grip in challenging conditions.

La Sportiva Mutant

Who should NOT buy

If you're a fan of a plush, soft midsole, the Mutant is quite the opposite—we found in the lab that is incredibly firm. Luckily, the market offers other options that can handle technical terrain with a softer midsole, such as the Nike Terra Kiger 9.

Moreover, the Mutant isn't ideal for those interested in maximalist shoes, given its narrow sole and limited cushioning. For a more cushioned experience, we suggest trying the Hoka Mafate Speed 4 or the Brooks Caldera 6, which offer a more maximalist approach to the off-road adventure.

La Sportiva Mutant

Breathability

Right from the start, the engineered mesh of the Mutant appeared to us as merely average in terms of breathability, but our assumptions were swiftly proven wrong—and that's the beauty of testing in the lab, revealing the real deal about trail running shoes.

Using our smoke-pumping machine to gauge breathability, we awarded the shoe an impressive 4 out of 5. This is an excellent score, especially for those planning to run in warmer climates. However, it also emphasizes the need for really warm socks in colder conditions.

Despite its nice breathability, we were intrigued to see that light didn't pass through as easily as expected. This often suggests a dense upper crafted from very thin mesh, a detail we could only verify under the microscope.

La Sportiva Mutant microscope

And there it was. An incredibly thin, multi-layered mesh that looked outstanding. Air circulates effortlessly through the tiny gaps, eliminating the need for additional ventilation holes.

La Sportiva Mutant microscope

In our final step, we dissected the upper to examine each part closely. It's exceptionally plush throughout, except in the toebox, to ensure adequate ventilation.

Test results
Mutant 4
Average 3.3
Compared to 76 trail running shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

During our hands-on inspection of the upper, we observed that the mesh isn't the coziest we've ever felt. This does result in slightly less comfort, but it brings a significant advantage—enhanced durability.

Our dremel test really put the upper to the test, and even without any protective TPU pieces in the test area, it held up remarkably well. Consequently, we awarded the Mutant a strong 4 out of 5 in this durability test.

La Sportiva Mutant Toebox durability
Test results
Mutant 4
Average 3.1
Compared to 56 trail running shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

The heel area felt durable right from the first touch, but to uncover the full truth, let's get the Dremel going once again.

Well, after our second Dremel test, we discovered yet another impressive score of 4 out of 5. This result is genuinely great and guarantees a long-lasting heel area.

La Sportiva Mutant Heel padding durability
Test results
Mutant 4
Average 2.9
Compared to 54 trail running shoes
Number of shoes
1
Heel padding durability
5

Outsole hardness

Then, we flipped the shoe over to analyze the FriXion White outsole, starting with its hardness.

La Sportiva Mutant

Measuring 90.3 HC, the outsole seems quite hard, suggesting a focus on durability. But the question remains—will the rubber prove its toughness in our upcoming test?

La Sportiva Mutant Outsole hardness
Test results
Mutant 90.3 HC
Average 85.3 HC
We use an average of four tests. The photo shows one of those tests.
Compared to 99 trail running shoes
Number of shoes
72.5 HC
Outsole hardness
95.0 HC

Outsole durability

Regrettably, the answer is no.

Following our more intense Dremel test—lasting 20 seconds at 10K RPM—we observed a 1.6 mm gap in the lug. This disappointing outcome is nearly twice the average damage we usually see in this test.

La Sportiva Mutant Outsole durability
Test results
Mutant 1.6 mm
Average 0.9 mm
Compared to 49 trail running shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

However, there's some good news here. La Sportiva has equipped the outsole with large lugs, which we'll discuss shortly, and a 2.0-mm thick outsole. So, it's highly unlikely that you'll completely wear out the rubber. Other elements of the shoe will definitely show wear and tear earlier.

La Sportiva Mutant Outsole thickness
Test results
Mutant 2.0 mm
Average 2.4 mm
Compared to 99 trail running shoes
Number of shoes
0.9 mm
Outsole thickness
6.5 mm

Weight

The shoe is unmistakably heavy at 11.4 oz (323g), a downside that's more apparent given its stack height. There's simply no way to sugarcoat it.

While it's true that the shoe feels somewhat agile in technical terrains due to its narrow dimensions, this advantage fades when you need to speed up on flat or uphill terrains.

La Sportiva Mutant Weight
Test results
Mutant 11.39 oz (323g)
Average 10.34 oz (293g)
Compared to 99 trail running shoes
Number of shoes
7.51 oz (213g)
Weight
13.37 oz (379g)

Cushioning

Heel stack

The heel of the shoe measures 33.2 mm, but it's important to note that this shoe has a thicker outsole than usual. This means there's less foam for the same stack height compared to other shoes.

La Sportiva Mutant

The heel is enhanced with protective elements that double as a heel cup, boosting stability effectively for rearfoot strikers.

We wouldn't classify this shoe as max cushioned, but in trail running, having less foam can be a plus. So, it will likely be suitable for many runners.

La Sportiva Mutant Heel stack
Test results
Mutant 33.2 mm
Average 32.2 mm
Compared to 99 trail running shoes
Number of shoes
16.1 mm
Heel stack
42.4 mm

Forefoot stack

In the forefoot, our measurement was just 21.9 mm, indicating a quite thin layer of foam underfoot once you deduct the outsole and insole. 

The Mutant isn't really designed for long-distance running, particularly for those who are forefoot strikers.

La Sportiva Mutant Forefoot stack
Test results
Mutant 21.9 mm
Average 24.4 mm
Compared to 99 trail running shoes
Number of shoes
15.2 mm
Forefoot stack
33.9 mm

Drop

The shoe's higher-than-average 11.3-mm drop contributes to its less favorable profile for forefoot strikers.

Combined with the low stack in the forefoot, we believe this design makes the shoe more suitable for heel strikers.

La Sportiva Mutant Drop
Test results
Mutant 11.3 mm
Average 7.8 mm
Compared to 98 trail running shoes
Number of shoes
-0.1 mm
Drop
17.3 mm

Insole thickness

The insole of the shoe features a typical amount of padding. When we measured its thickness at the rearfoot using a caliper, it came out to 4.7 mm.

La Sportiva Mutant Insole thickness
Test results
Mutant 4.7 mm
Average 4.7 mm
Compared to 99 trail running shoes
Number of shoes
2.7 mm
Insole thickness
9.8 mm

Midsole softness

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

Keeping in line with the Mutant's unique design choices, its EVA-based midsole also has its own quirks. It's exceptionally firm, measuring 36.1 HA, which is ideal for fans of very firm midsoles.

La Sportiva has also included a TPU plate in the midsole as a stabilizing feature, further increasing the shoe's firmness.

La Sportiva Mutant Midsole softness
Test results
Mutant 36.1 HA
Average 23.2 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 75 trail running shoes
Number of shoes
9.4 HA
Midsole softness (soft to firm)
39.0 HA

Midsole softness in cold

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

To simulate winter conditions, we placed the shoe in our freezer for 20 minutes. Afterward, we conducted the durometer test again. This time, the measurement came out to 38.4 HA.

La Sportiva Mutant Midsole softness in cold
Test results
Mutant 38.4 HA
Average 29.0 HA
Compared to 75 trail running shoes
Number of shoes
11.8 HA
Midsole softness in cold (soft to firm)
48.4 HA

Difference in midsole softness in cold

That's an excellent result as it represents only a 6.2% increase, which is quite minimal. However, given the midsole's inherent firmness, any difference in stiffness wouldn’t have been noticeable regardless of the change.

Test results
Mutant 6.2%
Average 26.7%
Compared to 75 trail running shoes
Number of shoes
0%
Difference in midsole softness in cold
100%

Stability

Lateral stability test

The Mutant, with its firm foam and design for technical terrain, offers great stability.

Another eccentricity from La Sportiva that we liked is the bizarre lacing system.

La Sportiva Mutant FusionGate

Integrated into the upper through their FusionGate technology, this design allows for adjusting the inner volume and how snugly the foot fits, enhancing stability on technical terrain.

Torsional rigidity

Due to its high sidewalls, particularly in the heel, and the brick-like firmness of its midsole, the Mutant exhibits significant torsional rigidity, enhancing its stability.

In our manual assessment, we gave the shoe a score of 5 out of 5 in this test.

Test results
Mutant 5
Average 3.5
Compared to 93 trail running shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

The heel counter is designed with comfort in mind. We found it to be more flexible and gave it a rating of 3 out of 5. This tried-and-true approach makes the shoe suitable for a variety of uses.

Test results
Mutant 3
Average 3.2
Compared to 91 trail running shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width in the forefoot

Now let's examine the dimensions of the Mutant.

We measured the sole at its widest part in the forefoot and found it to be 110.3 mm. This size is comparable to most trail shoes, but it leans towards a narrower design. This helps in effectively navigating technical terrain and also aids in not adding any extra weight.

La Sportiva Mutant Midsole width in the forefoot
Test results
Mutant 110.3 mm
Average 111.9 mm
Compared to 99 trail running shoes
Number of shoes
102.1 mm
Midsole width in the forefoot
126.0 mm

Midsole width in the heel

The heel is on the narrower side too, might be a bit too much for our liking at 86.3 mm.

For those concerned about rearfoot stability, a wider option that still manages technical terrain, such as the Hoka Speedgoat 5, would be a more suitable choice.

La Sportiva Mutant Midsole width in the heel
Test results
Mutant 86.3 mm
Average 89.6 mm
Compared to 99 trail running shoes
Number of shoes
77.2 mm
Midsole width in the heel
109.3 mm

Flexibility

Stiffness

To masterfully handle technical descents and adapt to challenging areas with roots or large rocks, the Mutant needs to be flexible lengthwise. Fortunately, it excelled in our 90-degree bend test with a score of 21.3N, solidly confirming its adaptability.

Test results
Mutant 21.3N
Average 28.6N
We use an average of four tests. The video shows one of those tests.
Compared to 99 trail running shoes
Number of shoes
10.5N
Stiffness
54.5N

Stiffness in cold

When exposed to cold temperatures, the shoe showed a slight change. After leaving it in our freezer for 20 minutes and re-testing, we found a fairly similar result, measuring 24.6N.

Test results
Mutant 24.6N
Average 38.8N
Compared to 96 trail running shoes
Number of shoes
11.9N
Stiffness in cold
92.1N

Difference in stiffness in cold

That's just a 15.5% increase, which, again, is hardly noticeable underfoot.

Test results
Mutant 15.5%
Average 35.7%
Compared to 96 trail running shoes
Number of shoes
0%
Difference in stiffness in cold
102%

Grip / Traction

Lug depth

Designed for adventurous runs on technical terrain, La Sportiva has equipped the shoe with deep 5.0-mm lugs for exceptional rock grip.

La Sportiva Mutant outsole

The lugs, a standout feature of the FriXion White outsole, are widely spaced and multi-directional, offering phenomenal traction on complicated surfaces. We think they are absolutely perfect for navigating surfaces like mud, roots, deep grass, or marsh trails.

La Sportiva Mutant Lug depth
Test results
Mutant 5.0 mm
Average 3.5 mm
Compared to 99 trail running shoes
Number of shoes
1.7 mm
Lug depth
5.8 mm

Size and fit

Toebox width at the widest part

With its narrow platform and being from a European manufacturer, it was obvious the fit would be snug, but we wanted to measure it.

La Sportiva Mutant fit

Sure, it's on the narrow side, but hey, the upper looks fantastic.

Our caliper showed the widest part of the upper at 95.3 mm, so it's ideal for those who prefer performance-fitted uppers. However, if you have wide feet, this shoe might not be the best choice for you.

La Sportiva Mutant Toebox width at the widest part
Test results
Mutant 95.3 mm
Average 98.7 mm
Compared to 99 trail running shoes
Number of shoes
92.0 mm
Toebox width at the widest part
104.9 mm

Toebox width at the big toe

In the big toe area, things improve significantly. The shoe doesn't taper excessively (78.3 mm), providing ample space for toes to comfortably splay out.

La Sportiva Mutant Toebox width at the big toe
Test results
Mutant 78.3 mm
Average 78.9 mm
Compared to 61 trail running shoes
Number of shoes
70.5 mm
Toebox width at the big toe
92.1 mm

Tongue: gusset type

The tongue lacks any gusset, meaning it's not secured to the sides, which could lead to it shifting during runs. Although the shoe tends towards a snug fit, this oversight is still a notable drawback.

La Sportiva Mutant Tongue: gusset type
Test results
Mutant None

Comfort

Tongue padding

The tongue is overly padded at 10.2 mm, which we see as a poor choice for this particular shoe.

La Sportiva Mutant tongue

Less padding could have sufficed, especially since the shoe is already quite heavy. A wiser move would have been to reduce some of that extra weight.

La Sportiva Mutant Tongue padding
Test results
Mutant 10.2 mm
Average 6.4 mm
Compared to 99 trail running shoes
Number of shoes
1.5 mm
Tongue padding
12.2 mm

Heel tab

At the back, we spotted a bizarre—again—finger-loop heel tab, the kind of cool design only a brand like La Sportiva, unafraid to take risks, could come up with. It's truly a standout heel tab, extending from the heel collar in a way we haven't seen in almost any other shoe.

La Sportiva Mutant Heel tab
Test results
Mutant Finger loop

Removable insole

The insole is removable, so you can easily put in custom orthotics if needed. But if you're unsure, the Ortholite insole that comes with it is pretty good and might be worth sticking with.

La Sportiva Mutant Removable insole
Test results
Mutant Yes

Misc

Reflective elements

The Mutant doesn't have any reflective pieces at all.

La Sportiva Mutant Reflective elements
Test results
Mutant No