Salomon S Lab Modular Shorts System – Review

Salomon announced a new “S Lab Modular” shorts system last summer that looked interesting but a bit fussy at the time. The system replaces the excellent S Lab Sense short that was in the line for a couple of years. I have used the S Lab Sense short extensively (like for every run for over two years or about 5000 total miles (8000 km) of running) and thought that it would be difficult to improve on the design. Although they changed the inner brief to a longer version in the 2nd year of production, I have preferred the original “classic” size  inner brief although both are very comfortable and great performers. A couple of images of the S Lab Sense shorts made from 2014-2016:

So it was with a quite a bit of trepidation that I tried out the new S Lab Modular System. I have been pleasantly surprised and it appears that comfort might be marginally improved (time will tell).

Salomon S lab Modular system overview

The system consists of an inner brief (boxer length or longer), an integrated belt (for hydration, fuel, and stowage), and an outer (in three lengths). You choose what works best for you in whatever combination you like. Here is a short video that illustrates the system:

The system is pretty flexible but it also seems a bit fussy, particularly since the S Lab Sense short was so good and just involved buying a pair of shorts- no “system” involved and the Sense short had everything that this new product offers- comfortable shorts and integrated hydration/fuel/stowage. But the Sense shorts did not offer the flexibility for different lengths and types of additional support that the new system allows for.

Since there are no studies that show any significant level of efficacy for the use of compression garments in endurance sport, I have never been that interested in the Exo line that Salomon has had for years. I have found the garments to be uncomfortable and, in some cases, they have lead to painful chaffing in some bad places. All of the Exo stuff I purchased over the years is now gone off to the local thrift store. Likewise, with this new system I have no interest in the Exo bits so the review here will be of the non-Exo components. I know there are a lot of fans of the Exo-type compression/support stuff but I would suggest that those who are using it might think about the reality of “the placebo effect”…. but, to each their own!

the system i use

From the available elements of the modular system, I chose the boxer briefs, the integrated belt, and the 6″ outer. This combination most closely replicates the original/second generation S Lab Sense shorts- it is also the least expensive combination (but still a whopping $165 US retail). If you go with an Exo set-up be prepared to spend up to $270 US retail!


integrated belt



The comfort of any short is highly dependent upon the performance of the liner as this is the part of the short that interacts most closely with the body and some sensitive areas. To be direct, the S Lab Modular boxers are “uber” comfortable- the sort of experience where you put them on and use them but never have another thought about them until you realize that they are essentially transparent in use and exactly what is preferred. They stay put and I have had no need to make any adjustments whatsoever in mountain runs exceeding 25 km (2-2.5 h) in length. The “37.5” material used in their construction is a brand of fabric compositions that use ultra high surface area particulates to help in absorption and evaporation of moisture to help regulate body temperature and humidity in the micro-climate at the fabric-body interface. These materials have been found to be very comfortable in those garments that sit next to the skin. In this case I agree- the fabric is very comfortable next to the skin and all of the “working” parts that a brief interacts with.

Salomon S Lab Modular short system- my version is the boxer briefs, the integrated belt, and a 6″ length outer.

The boxer briefs have two “flap over” pockets on each hip, apparently for additional fuel or keys or whatever might fit. I see these pockets as a place for secure storage whilst running since they are no very easy to get to once the whole system is in place. I currently use them for keys on the very rare days that I drive or ride a bike to a trail head (I live where the trails go right out the door and directly to hundreds of miles of single track), otherwise the pockets are not used. One thing to note about the pieces in this system is that there are no hems- nearly every material edge is unhemmed fabric with a thin, slightly sticky polymer layer on the inside (toward the body side). This layer serves two purposes- first, it prevents unraveling of the fabric and, secondly, it provides assistance in keeping the fabric in place. The areas where there is a loop of fabric over an edge is at the elasticized sections at the hips on the outer piece and at the upper edges of the pockets on the integrated belt.

Also these briefs can be used for other garments, e.g I have used them as a liner for some 3/4 tights and as a base layer for cross country skiing under a pair of thermal tights. In both cases they have worked well.

A side and back view of the boxer briefs showing the “flapover” pockets at the hips and the hemless fabric terminations. Also note that the fabric being used is part of the “37.5” brand of fabric compositions that use ultra high surface area particulates to help in absorption and evaporation of moisture to help regulate body temperature and humidity in the micro-climate at the fabric-body interface. Note the hemless fabric edges and the snaps for attachment of the integrated belt.

You will have noticed the three in-line “holes” placed in a vertical orientation- these are actually the male side of a set of snaps that are used for attachment of the integrated belt. There are another set of snaps on the front of the briefs (see image of entire system above and marketing photos of the briefs, also above). In my experience the snaps are not noticeable against the body during use.

The integrated belt snaps into the briefs and nestles nicely around the waist. There are four pockets distributed around the entire circumference of the belt- two longer pockets across the front and back and two smaller pockets at the hips. All pockets have small tabs centered on the individual pockets to facilitate access.

The integrated fuel/hydration/stowage belt showing the female side of the snaps used for attachment to the briefs, the hemless fabric edges, and one of the small tabs used for access to the pockets.

I found that it is best when using the belt to attach it to the briefs before putting the briefs on. It is difficult to align the snaps at the rear without a visual cue. For those that always use the briefs with the belt they can be left assembled even through wash cycles. However, one will most likely wash the briefs after every use whereas the belt can be used for numerous runs without necessarily needed to be washed.

The integrated belt attached to the briefs showing the position of the belt, the mesh pockets around the periphery of the belt, and the hip pockets on the briefs.

Finally there is the outer piece that is positioned over the briefs and snuggles up to the bottom edge of the integrated belt. The fabric of the outer piece is extremely light and breathable and has a “barely there” feel. This piece appears to use a “lost fiber” process where a fabric is purposely constructed with a proportion of the fibers being composed of a material that “disappears” during the final stages of production. Such a process yields a fabric that has very fine openings that are otherwise very difficult to achieve. The fabric also has a DWR treatment that could help minimize soak-through in wet conditions.

A backlit image of the outer piece fabric showing a fine distribution of openings throughout the construction. This appears to be achieved via a “lost fiber” process.

The 6″ version of the outer piece of the modular system showing the elasticized waist sections, the “barely there” fabric, the hemless terminations, and a 2″ slit up the sides.


I’ve used this modular system for about 150 kms (100 miles) of mountain running with a long run of about 30 km (about 3 h). This use has been in temperatures ranging from 40F (4C) to 80F (27C) in generally low humidity (<50% rel) conditions.

I have found the system to be very comfortable under all of the conditions that I have used it in. As noted earlier, one of the primary aspects of this system is it’s transparency, i.e. that it is in place and there is nothing about it that you notice or feel needs adjustment. This is a great thing and one that is not typical in my experience. It hints that Salomon have really thought this system out and tested it extensively for comfort.

Given the epic snow year here in the Central Idaho mountains, we have quite a bit of runoff and what are normally “creeks” have become virtual rivers and a few of these cross the trails that I run regularly. So, I have been up to my waist in rushing water a few times and found that the system stays put and dries out quickly- the outer piece dries very quickly (there is not much there to absorb water in the first place). The briefs and belt also dry quickly, at least in the lower humidity that I have tested them. The fabrics also stay relatively dry in hotter temperatures as the 37.5 fabric is designed to maximize absorption  and evaporation- and it does seem to work well.

As far as fit, I have universally used the Salomon size small and the size small in the modular system fits as expected. The only part of the fit that I am not entirely satisfied with is the length of the 6″ outer piece- it is a bit too long for my preferences as I prefer the 5″ inseam length of the Sense short. The 4″ outer piece is too short. I still do not understand the appeal of the very long, very loose “basketball” length running shorts that have become popular and the 9″ version of the outer piece is just such a length. Once again to each their own… and Salomon have provided a way to pick and choose accordingly with this system- it is one of the strengths of the product line.

Use of the integrated belt has worked well for fuel and stowage but I find I am constrained to a 250ml soft flask size maximum. The larger flasks (500ml) are just too large and heavy when full and they can bounce out. Also the tightness of the mesh pocket fabric over the bite valve can lead to leaking of the fluid so one needs to take care as to where the bite valve is placed. I typically have the valve facing upward at an angle and over the lip of the pocket so that the mesh does not stress the bite valve. You can get two 250 ml soft flasks in the belt (one front, one rear) but I find it to be a bit heavy and slightly bouncy, but for a long run you will be emptying the flasks so this situation would only last for a while.

I have been able to get eight gel packs, an S Lab Light jacket, a long sleeve tee shirt, salt tablets, one 250 ml flask of water (or fuel), and a headband (or hat) in the belt without altering the comfort or having too much bounce. With the exception of additional hydration the belt essentially replaces a typical race vest. If you choose to use the Salomon (or other brand) hydration glove product it is possible to carry up to 1l of fluids (or more if you use a hard-bottle system). For most races this capacity will be sufficient to get from aid to aid without difficulty even in very warm conditions. So as a race alternative, the modular system with the integrated belt should work well- I’ll be finding out for sure in few weeks.

Also you do not have to use the integrated belt as the system works without it in place. I have done a couple of longer runs without the belt but instead used a Sense Set 1 hydration vest. Either way these are very lightweight options for longer runs or as a race set-up.


The price of the system as tested is $165 US and is about the same as the $150 US for the prior S Lab Sense short. It’s still expensive but the performance and flexibility may justify the price- it will depend on your expectations. Also the briefs can be used with other garments as noted above.

However, if you go with Exo program in this system you will be at $270! I think that is over the top particularly since there is no basis for the so-called “benefits” of the compression parts of the system.

bottom line

An “uber” comfortable, flexible, and high performance shorts system for trail running and racing. A bit “fussy” but still highly recommended. However, there is extremely limited availability in the US at this time. Not so for Europe and I’ll be picking up a few more pieces when in the Trient-Chamonix area this summer.

12 thoughts on “Salomon S Lab Modular Shorts System – Review

  1. These seem like a solution in search of a problem to me. I already own a plethora of shorts, briefs and belts – my collection is boundlessly modular.

    • Hi Andy,

      I agree with you as far as the “solution in search of a problem” aspect but sometimes in marketing it is the pointing out of a “problem” that a consumer did not know they had that can lead to successful products. Auto companies are probably the most persistent in this sort of technology push. Example: A friend showed up with her new 2018 Audi Q5 the other day and showed me around (I have 2014 Q5). Nothing particularly exciting as far as exterior design but Audi now has something called “Virtual Cockpit” which is a bunch of enhanced multi media interface stuff including a head-up display on the windscreen. As I interacted with this set of features I realized that yes, there were (are) problems that I did not know I had and that this new system addressed some of the newly realized problems. It can often be a matter of perspective as to whether there is a problem to solve or not.

      In this case I find that the S Lab Sense boxer briefs are much more comfortable than any liner in any of the shorts that I have ever used- including the S Lab Sense shorts of 2014-2016. So, by combining these briefs with whatever length “outer” I prefer, gives me, the consumer, more flexibility (and comfort) than I have had in the past. Integrating the belt is sort of a toss up as to any improvement in performance or comfort as the numerous belts available are already comfortable and high performance, however this new belt is super lightweight and minimalist, both of which appeal to me. Also, the system does give one the option to not wear the integrated belt (and to not have any pockets other than the hard to reach gel pockets on the briefs) for shorter or supported runs/races- of course, this is true for other non-integrated accessory belts as well but, with the exception of a very few, none are as minimalist as the S Lab integrated belt.

      Did I have a problem to solve prior to the advent of the S Lab Modular system? In retrospect, yes- I was not as comfortable as I could be with the new system.

      The other side of this is a benefit to the manufacturer- Salomon no longer needs to design, manufacture, and sell numerous individual garments that they perceive to be the best combination of inner, outer, and belt. They now just supply the components and the consumer decides how to put together a system that works for them. Salomon are going this direction with their high-end running shoes with the launch of the S Lab ME:sh program that has been rumored for over a year:

      Are these good, sound approaches to high-end products… time will tell, but I expect there will be some very goofy shoe component combinations out there and some quirky shorts set-ups as well but if, in the end, these combos work better for the individual consumer then I will suggest that the program is successful.

      • Robert,

        Thank you as always for your reasoned and convincing take. As I see it, the main challenge for sports apparel manufacturers is that the stuff wears incredibly well – I have well-used pieces from 10+ years ago that still look practically new. Hence the need to sell innovation which may, or in most cases may not, amount to anything. As a man with a cupboard full of this stuff, you’ll forgive me a bit of cynicism.

        But in this case, you do make a compelling case. Even a hard-boiled skeptic like myself is tempted to take the plunge, just to see what I may be missing. I’m off to lash myself to the mast…

      • Hi Andy,

        Yes, high quality athletic gear generally does wear very well. I was recently assigned the duty of cleaning out my portion of our closet and, just as you, there were 10 year old shorts and shirts that look as new and have significant life left- and this is not due to lack of use. So off to the thrift store and, in some cases, to the bin went a substantial pile.

        The largest improvement that I noticed in comparing these older garments to the newest is the reduction in weight. The new stuff is just so light, airy, and minimal in comparison- perhaps it will not wear as well?

        Do try out the modular system- I continue to find it very comfortable and “transparent” (in the right way). And now with significant use, perhaps even economical: the outer, depending on your environment, can be used multiple times with just a rinse under a tap as the fabric is so light it dries very quickly just hanging on a peg. What this means is that one can have a system consisting of multiple Sense boxers and just one (or two) outer pieces. When totaled up, for example, three Sense boxers and one outer yields the equivalent of three pair of “standard” shorts. In US$ that’s 3 X $55 for the boxers and 1 X $60 for a 6″ outer for a total of $225, then divide by 3 and you get $75/”pair”. That is to be compared to the $150/pair for last years S Lab Sense shorts. Combine this with the $50US S Lab Modular belt (which can also be rinsed out and dried quickly just like the outer) and you have all the function (and more) of the Sense shorts. So, a big savings for a very comfortable and flexible system. One could also add different outers depending on use (although I continue to not understand the utility of the long, baggy shorts that are so popular today- it must be some sort of fashion thing) and still not approach the cost associated with “standard” high performance shorts. The question will be how durable are the boxers… only time will tell.

    • Hi Jeremy,

      OK, I’ll hold you to that!

      But yeah, I have had generally good experience with French manufactured goods… however, my father had a mid-60’s DS 21 that we affectionately referred to as “Le Terrible” not after the destroyer but more because of the dual meaning attributed to “terrible”. We loved it and hated it and had a difficult time getting parts for it.. but it was a blast to drive and about as French as anything in the US… and that we very much liked!

  2. Hi, I struggle to find running shorts that can hold a phone (iphone 6 in a case) without bouncing around. Would this be the answer?


    • Hi Craig,

      I do not have personal experience with carrying an iphone in these shorts/energy belt- I got rid of (i.e. physically destroyed) my “smartphone” when I retired and will never want one again! But I have seen a few notes by users of both the shorts+energy belt and just the energy belt portion of the system who have indicated that it holds an iphone nicely with minimal bounce.

      Hope this helps.

  3. Hi great review thanks. I am curious about size as I tend to fall between small and medium. I have 31″ hips and 30″ waist. What size would you recommend?

    Thanks Simon

    • Hi Simon,

      Based on the Salomon sizing information and personal experience, I should think that small would work. But best to try them on if you can. Some shops here in the US allow this whilst others do not. We also have Running Warehouse that will ship for free both ways so you can try a few sizes and then return the ones that do not fit at no cost to you. Perhaps there is a similar outlet there in the UK?

      Hope this helps.

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