Salomon S Lab Sense Ultra 2017 – final update – I can’t wear these shoes out!

As an initial impressions review, a 300 km update, and a 1200 km update have documented, the Salomon S Lab Sense Ultra 2017 has been an outstanding performer on just about any trail in just about any condition. Let’s now add to that list of superlatives with the words: incredible durability.

Salomon S Lab Sense Ultra 2017 after about 2000 km of trail use on a 50/50 mix of buffed and rocky/technical Rocky Mountain terrain. Other than wearing through one of the diamond-shaped lugs at the rear on the right shoe, the outsole is showing only minor additional wear- super durable! The shoes are fresh out of the washing machine in this (and all other) picture(s)- they have been washed in my Bosch Axxis+ washer and spun at 1200 RPM about 15 times all with no damage or excessive wear.

I now have in excess of 2000 km (1200 miles) on the S Lab Sense Ultra and these shoes are still going strong. Past experience with S Lab shoes has lead to excellent outsole and upper wear but as 1600 km is approached the midsole and ProFeel Film begin to loose performance- the shoes typically loose significant fractions of initial cushioning and the ProFeel Film deteriorates to the point where sharp rocks become increasingly difficult to step directly upon. None of this decrease in performance has yet appeared- even with significantly more mileage on the S Lab Sense Ultra when compared to previous S Lab shoes (S Lab Sense, S Lab Sense 3&4, S Lab Sense Ultra (original model), S Lab X-Series, and S Lab Sonic).

Close-up of the outsole of the right foot S Lab Sense Ultra 2017 showing hardly any wear other than wear-through on one of the diamond lugs at the lateral rear. These shoes have lost none of their initially superior traction in virtually all conditions- wet, dry, muddy, rough rocky, slick rock, submerged rock, etc.

The midsole cushioning is holding up very well and although there is a slightly noticeable difference in cushioning when directly comparing these used shoes to a new pair of the same, it is not dramatic and it is not affecting the on-trail performance of the shoe. The shoe remains ultra-comfortable even for longer runs (20-30 mountain miles (3-5 h depending on vert) for me). There might be a tad bit of sharp rock coming through but it is minor and certainly not significant enough to put the shoes aside and move on to a new pair.

The S Lab Sense is holding it’s structure quite well and still runs identically to when the shoe was new. The upper is also showing excellent resistance to wear. 

The upper has held up exceedingly well as they show no excessive wear in any of the high strain areas that have been issues in past S Lab shoes. In fact without the dust-decoration of the edges of the SensiFit overlays, the uppers look as new. The heel counter shows the typical wear-out at the expected place (top edge of heel counter at the furthest aft position).

View of the S Lab Sense Ultra uppers after 2000 km- no excessive wear anywhere. Minor wear-out at the heel counter is typical at this mileage.

This type of overall low wear in a racing shoe after 2000 km is singular in my experience and demonstrates what a great product this S Lab model is.

Another view of the S Lab Sense uppers after 2000 km of trail use showing virtually no wear-out and continued durability.

Salomon may have made that rare mistake of putting out a trail shoe that is over engineered from a durability perspective but still, even at high mileage, retains all of the trail performance expected in a racing shoe. I look forward to even more miles on this pair and know that I will be well served by the two additional pairs that I have “stocked” in the shoe closet!

bottom line

Probably the most comfortable, highest performance, and durable shoe yet in the S Lab line. Highly recommended and look for sales this fall as the S Lab Sense Ultra 2 for 2018 is adding weight- not a good sign.


Salomon Sense Ride – not impressed

The Salomon Sense Ride trail running shoe was pre-announced at the Summer 2016 OR  and became available in June 2017. I received a pair a couple of weeks ago and have put about 150 km on them in a 50/50 mix of smooth buffed singletrack and rocky technical trail. After reading a review by some trusted users I was looking forward to a potential lower cost shoe that had much of what the S Lab Sense Ultra 2017 offers and could be used for the bulk of training, saving the S Lab Ultra for races and more technical efforts. Well, miracles are fantasy and that is what has prevailed in this case. Based on my running mechanics, style, and terrain the Sense Ride is no S Lab Sense Ultra.

Salomon Sense Ride is a cushioned trail running shoe with some new anti-vibration technology (Opal inserts across the footbed). The colorway shown here is a dark blue with orange accents- the orange is much deeper in hue but the sunlight in Sun Valley is currently being filtered through a bit of smoke from fires from the north and south and this affects the color sensitivity calibration of my camera image sensor for directly reflected light. A truer color representation is evident in the indirectly reflected light pictures below.


The Sense Ride has the typical “rocker” profile that is common among shoes with higher cushioning.

A mild but effective rocker is used on the Sense Ride.

All of the Salomon fit technologies are present including Endofit (a separate inner sock-like element engaging the foot), Sensifit (outer polymer overlays integrated with the QuickLace system), and the QuickLace system. The tongue is minimally cushioned.

Flexibility is good whilst still including the ProFeel film technology for rock protection. The flexibility is accomplished with three lateral flex axes that traverse the width of the outsole. There is a similar flex axis at a slight diagonal across the lateral heel area. Proprioception is OK but is inferior when compared to the Sense Pro Max high cushion shoe, and is nothing like that found with the S Lab Sense Ultra.

The stack comes in at 27mm heel/ 19mm forefoot which is a nice “cush” level and 1mm more than that offered in the S Lab Sense Ultra. But this shoe also has Salomon’s new vibration-reduction technology called Vibe which, in this shoe, includes a full-foot insert of the vibration-absorbing Opal material. This is different than in the Sense Pro Max (and the S Lab Sonic 2) where the Opal is two separate inserts- one in the forefoot and one in the heel. The Vibe technology is nicely described in this review of the S Lab Sonic 2. I am not a fan of the Vibe technology and there will be more on that below.

The outsole utilizes the Premium Wet Traction ContraGrip material which is an excellent performer across the board for the highly variable conditions of trail and mountain running.

My size US 7.5 (40 2/3 EUR) weigh in at 233 gms (8.2 oz) which is well within the weight range for a racing shoe. This shoe is not a Salomon racing product as it is intended for general training and trail running, but it could clearly be used as a racer.


The Sense Ride upper is constructed in a fashion that is very similar to the S Lab shoes and includes all of the fit technologies that have made the S Lab shoes such a near-optimal fit benchmark in trail running products. As mentioned above, these fit technologies include EndoFit, SensiFit, Salomon QuickLace, and a shaped foot bed. The Sense Ride also has a substantial OrthoLite foot liner which provides a bit more cushion.

The upper mesh is a reasonably light weight material but clearly heavier and less flexible than the mesh used in the S Lab Sense Ultra. This mesh does not drain as well or dry as quickly as the S Lab Sense Ultra- both of which are important considerations for broad use on trails.

The Salomon Sense Ride has a very large volume that does not accommodate smaller feet. The shoe is built on a very different last to that used for the S Lab Sense Ultra. It seems to be designed for bigger, beefy feet. Drainage and associated drying are OK, not great

I am not sure how this happened but somehow Salomon have managed to totally screw-up the fit of this shoe even with the superior fit technologies being employed. First off, the upper has too much volume and it seems that Salomon is trying to accommodate some foot shapes that are so voluminous that the standard fit technologies are not capable of providing a secure fit for lower volume feet. Second, there is a large difference in the shape of the last for the Sense Ride. This is exhibited when one puts the Sense Ride shoe on where it just easily slides on as if you were putting on a loafer- with support and fit on par with such a shoe (or a Hoka or Altra). The S Lab Sense Ultra is built on a very different last that leads to a fit more like a cross country ski boot where the foot slides in with a bit of constraint and then engages in a final position that is snug and fully supporting around the entire foot leading to a high level of control and proprioception. Control and proprioception are not strong points for the Sense Ride.

I thought that perhaps I needed to size down and I tried this with a US 7 (40 EU) and found no improvement in fit and the shoe at this size was close to being too short for long run comfort. So sizing down will not fix the problem.


With a 27mm/19mm stack this shoe should feel ultra-cush but such does not obtain. I find the “ride” of the Sense Ride to be firm when compared to the S Lab Sense Ultra and this is obviously due to the inclusion of the vibration-reducing Opal inserts. Just as I found with the Sense Pro Max, the Opal material leads to a somewhat jarring experience on trails and this is something that, for me, is undesirable. I still do not have, nor have Salomon offered, an explanation of why the mid-to-high frequency vibrations that the Opal supposedly eliminates are so important. I expect that there could be some correlation to muscle micro-tearing but that is going to be very much a function of individual biomechanics and biometrics that a lot of data would need to be collected to support any claim for broad efficacy. As a lighter weight runner I find the material to not be an improvement. A heavier runner might have a different experience.


The outsole has a design that is essentially identical with the S Lab Sense Ultra and uses the same Premium Wet Traction ContraGrip material. The lug design and material combine to provide some of the best broad-use traction performance available today. As mentioned earlier three shoe width wide flex axes are included in the forefoot with a smaller axis at a diagonal at the heel. These add flexibility to a shoe that would otherwise be very stiff, given the full foot Opal insert.

Salomon Sense Ride outsole. Nearly identical to the S Lab Sense Ultra in design and materials. One of the best performing outsoles currently on the market.

This outsole is very durable as i now have over 1500 km (1000 miles) on a pair of S Lab Sense Ultras with hardly any sign of wear- even in the rough, rocky training terrain that I use on a daily basis.

running performance

Primarily due to the very poor fit but also due to an overly firm ride, the Sense Ride exhibit a weird combination of lack of control with a somewhat jarring feel. The worst of two worlds. On any trail even hinting at “technical” these shoes start to detach from my feet and lead to a disjointed and disturbing trail experience. Although the Opal inserts begin to “break-in” after about 30 miles, the firm ride never seems to dissipate.  Compared to the super-high control, very high proprioception, and super-cush ride of the S Lab Sense Ultra the Sense Ride are embarrassingly bad. After 150 km of hoping for “break-in”, these shoes have been put to the back of the shoe closet where they are likely to gather a thick layer of dust.


$120US. A seemingly great price considering it is a Salomon shoe with all of the superior fit technologies and a new vibration reduction material. But given just the poor fit the shoe has zero value.

bottom line

A poorly fitting, low proprioception, firm riding shoe that cannot be recommended*.

*note: I am a lighter runner (125-130 lbs) with a predominant forefoot strike and a high cadence (190-200 spm @ training pace). A heavier runner with a midfoot-to-heel strike and/or a lower cadence may find a very different feel in this shoe.


The Road to Minneapolis (maybe)

Ordinarily a US skier might be quite thrilled to have the Masters World Cross Country Ski Championships (MWC) in their home country. The convenience, familiarity, and general ease associated with attending all add up to a positive consideration when deciding whether or not to compete. So when it was announced that the World Masters would be in the US in 2018, Team Bumble Bee was excited… that was until it was further announced that the MWC competition would take place in a major metropolitan area- right within the city limits of Minneapolis, Minnesota.

Having spent a lot of time in Minneapolis from 1999-2009 in extensive consulting with a major firm based there, Bumble  got to know the city and it’s environs. While not a place that he (or Bee) would choose to live, many who do live there extol the long list of great attributes that the city has to offer. Unfortunately, these attributes do not include consistent snow. In fact good snow years have been the exception for at least the last two decades. Cancelled or moved races have been commonplace in the Minneapolis area and when there is sufficient snow it is often of marginal quality and coverage. The organizers have committed to a significant upgrade to their snow-making capabilities to ensure at least 10 km of tracked trail in the event of low or no snow (provided the temps are low enough to make snow). However, man made snow is not something that we look forward to racing on, particularly when there will be excellent snow conditions at numerous other US races in the same time frame.

View of downtown Minneapolis from Thomas Wirth Park, site of the 2018 Masters World Cross Country Ski Championship January 19-26, 2018. Photo credit: Richard Sennott/Star Tribune.

Additionally, having a Masters World Championship in a city is of questionable value given all of the inconveniences that a city environment places on a cross country skier. In Minneapolis, among these inconveniences are: horrendous traffic, poor public transportation (although the organizers are supposedly offering frequent shuttles to the race site from Downtown hotels), dicey neighborhoods, expensive food (and IMO hard to find “good” food independent of price), potentially super cold temps (ca. -20F), dirty snow, and flat competition courses. What are the positives for a competitive skier? I can’t think of any.

View of the start/finish area at the 2017 Masters World Cross Country Skiing Championship in Klosters, Switzerland. There will be no mountains, or particularly challenging courses, in Minneapolis.

Arguments for awarding the MWC to Minneapolis have been centered on the “uniqueness” of having a MWC in an urban area, the ease of travel, plenty of accommodations, “City”-type extracurricular activities (local cultural attractions and events), the fact that Minneapolis has the highest concentration of cross country skiers in the US, and a committed local organizing committee. I could provide a point-by-point argument against each of these reasons (with the exception of the last point- the cross country ski community in Minneapolis is likely the strongest in the nation), but such would not necessarily be constructive. I will, however, just point out the most critical factor for a successful MWC- reliable and good snow conditions on challenging courses. There are so many nearly ideal venues in the US where the MWC could have been held it is disappointing that none were up to the task of hosting the competitions. Well, that’s just the way it goes in cross country skiing in the US.

Although Team Bumble Bee has begun a structured 7 month training period with MWC Minneapolis as an “A” event in late January, we are seriously considering not going to the competition. We may just fly in for 3-5 days and do two or three individual races and skip the relay. There are a lot of other very well run races on exceptional courses during the WMC period and any one of these will be preferable to hassling with trying to race in a major metro area that has inconsistent to very marginal snow. We will keep options open until the last minute but as of this writing it is very much up in the air as to whether we will be attending.

But as Bee frequently points out: a race is a race, everyone has the same course, and we are not likely to find such high quality age-graded competition anywhere else in 2018. So it might be best to just grapple with the downsides of an urban championships and start developing “coping strategies”.


Independent of these operational challenges during the MWC, intensive, structured, training continues. With just a few tweaks we will be following the same training progression as documented in detail in the 10-part series posted last season in the run-up to the Klosters MWC of March 2017. The training structure worked well for both Bee and Bumble and this is summarized in the wrap-up post. Bumble has work to do on downhill skill development and this is well underway and will be the subject of a future post. We have also added a few new elements to strength training as well- specifically, plyometrics. This will also be the subject of a future post. Suffice it to say that we are finding plyos to be a critical element in the development of explosive power and coordination, particularly for us “old people”. We have developed a matrix of plyos that are targeted for old people who have somewhat compromised connective tissue. Although not as challenging as “standard” (young person) plyos, these exercises are very effective in maximizing available explosive power from typical “geezer” physiology. Stay tuned for details.

Salomon S Lab Sense Ultra 2017 – 1200 km Update

This is a short, and final, update on the performance of the 2017 Salomon Sense Ultra. As indicated in an initial review and a 300 km update, The Sense Ultra has performed exceedingly well… and this has continued  in many additional kms. I can say without hesitation that if you are looking for a shoe with outstanding technical capabilities along with “long run” comfort, the Sense Ultra should be at the top of your list.

Salomon S Lab Sense Ultra 2017 after about 1200 km of use on a 50/50 mix of rocky technical and buffed out single track in the Norther Rockies of Idaho’s central mountains. Even after this much use the shoes are entirely intact with plenty of remaining cushion.

In about 1200 kms of use on a 50/50 mix of rocky technical and buffed out single track in the Norther Rockies of Idaho’s central mountains, the Sense Ultra have held up very well and are still going strong with performance that has hardly diminished. From the excellent proprioception and outstanding fit to the optimized level of cushioning, I have experienced no significant changes. The outsole, as usual, shows very minimal wear even on the abrasive, rocky terrain that I typically run on here in the Northern Rockies.

Outsole of the 2017 S Lab sense Ultra after about 1200 kms of use. Hardly any noticeable wear except in the expected area of the lateral heel typical of wear with my running gait. Dry and wet traction is still at the highest levels and grip on rock continues to be excellent.

The shoe construction, materials, and fit are intact and continuing to perform at the highest levels. The Sense Ultra are the most durable shoes I have experienced in many years of about 3500 kms per year on rocky mountainous terrain. Very impressive.

I cracked out a new pair of Sense Ultras for a 25 km mountain trail race with 1000 m of climb and descent a couple of weeks ago and barely noticed the difference between the well used first pair and the new, out-of-the-box pair. Quite remarkable!

They were not as “rocker” to start with but the Sense Ultra exhibit a significant “rocker” after 1200 kms of use.

One concern I noted at the outset was a “wrinkle” that had formed on the forefoot upper mesh that looked like it might develop into an area that would see excessive wear and potentially develop a hole. That did not happen as the upper mesh material is durable enough to withstand the extra abrasion and strain of the “wrinkle”.

Area on the medial forefoot that developed a “wrinkle” early on. Associated concerns over premature wear-out have not materialized and the upper mesh fabric shows no evidence. of breakdown

If there is one issue that is worthy of note, it is the fit as it concerns steep (30%+ grade) and/or typical mountain grade (5-20% grade) fast (sub 6 minute pace) downhill running. I hesitate to bring this up as I question my abilities in downhill running, but I find that the larger toebox design of the Sense Ultra leads to excessive movement of the forefoot upon plant and concomitant loss of proprioception and increased frictional forces on the bottom and sides of the cutaneous forefoot. This is something that I have gotten used to but I think that the shoe would be improved if the forefoot fit was bit tighter. As the fit in the forefoot is quite a personal thing dependent on exact foot shape and other factors, my experience may not be generally applicable. I guess this is the type of thing that Salomon hopes to provide solutions to with the S Lab ME:sh program.

bottom line

I say with confidence that the Salomon S Lab Sense Ultra 2017 is a “sweet spot” technical mountain trail running shoe suitable for both training and racing with excellent durability that retains significant fractions of cushion throughout the life of the shoe. The shoe is well worth the price of $180 US on a cost per mile basis. I expect to get even more kms out of this shoe as it is still very comfortable at 1200 kms. Highly recommended!

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.

Salomon S Lab Sense Ultra 2017 – 300 km Update

Note 20 June 2017: Salomon have just announced the S Lab Sense Ultra 2 which is said to be available Spring 2018 (likely in Jan/Feb 2018). The new version includes more cushioning and a wider last in the midfoot. Salomon have also incorporated some technology from their cross country ski boot designs for skate boots- a stiff plastic element that crosses over the foot just below the ankle and is integrated with the speed lacing. This element is called “Skin Guard” and supposedly allows for better control on descents. Although not as adjustable as the ski boot equivalent, the “Skin Guard” looks like it might be an interesting development. Unfortunately, the shoe is now heavier at 300 gms for size 9 (US). Pictures and brief description here.

I have provided a 1200 km update on this shoe.



Even though we have only just finished up the ski season (the last grooming was this past Sunday (7 May), I have been able to get out running a fair bit. The epic snow year means the trails are opening up slowly so I have not spent much time up high on the more technical rocky terrain as these areas are still under 3-6 feet (1-2 m) of snow. But I have been able to find some dirt, some rock, and, mixed with some snow fields, pieced together some reasonable length runs of 15-25 km. In total I have about 300 km on the 2017 Sense Ultra at this point with about a 50/50 mix of dirt/rock and snow.

After about 200 kms, there hardly any noticeable wear on the outsole, no excessive wear on the uppers (even though I have postholed through a fair share of crusted snow fields where abrasion is very high), and no noticeable reduction in cushioning.

The performance of these shoes has been outstanding! Salomon have truly hit a “sweet spot” of cushioning, grip, trail feel, and weight. The grip has been superior in all of the conditions that I have been able to test- dry and wet dirt , mud, clay mud, snow, ice, and wet and dry rock. All of these on rolling and steep (up to about 40% grade) trails. The trail feel is very good but not as transparent as in the S Lab X-Series (Sonic) and S Lab Sense. The weight (about 260 gms for these 7.5 US 40 2/3 EU) is not as noticeable as I thought it might be. But the most prominent feature of these shoes is the mid-foot support and the added cushioning.

The design of the shoe does an excellent job of securing and supporting the mid-foot and placing a generous amount of cushioning in this region and this makes for a huge improvement in comfort both in shorter (<15km) and longer (>25km) runs. As a forefoot striker, as I tire my midfoot begins to increasingly make contact coincident with the forefoot and support and cushioning in this area becomes critical for comfort and efficiency. I find the S Lab Sense Ultra to maintain a high level of comfort throughout runs, independent of the state of muscle fatigue and it is apparent that the onset of foot fatigue is pushed further out in time and distance compared to other shoes that I have worn (e.g. Sense, X-Series, Sonic, S Lab Wings, etc.). There is also substantial cushioning in the forefoot and this may be playing a role as well. Of course, the heel is even more cushioned and this is very welcome on long (> 3km) steep downhills that are typical here in the Northern Rockies (as well as in the Alps, where the  steeps are truly steep!). Combined with the excellent proprioception, bombing downhills in these shoes is a real pleasure and even at this early stage in transitioning from skiing I am finding some significant improvements in downhill speed.

The Sense Ultra also have very good glissading capabilities. It is not clear why but these shoes will glissade down a steep snowfield with significantly more control than I have experienced in other S Lab products. I suspect that the lug design is playing a role since the diamond shapes are oriented in way such that they may be providing a certain amount of directional stability. As a cross country skier I am intimately familiar with and comfortable on a narrow platform and the control on snow with the Sense Ultra is something like what a ski feels like, albeit minimally. I have much more control in these shoes on long glissades and this has been a welcome feature of the design given the amount of snowfield running I have been doing.

After about 300 kms, there is hardly any noticeable wear on the outsole, no excessive wear on the uppers (even though I have postholed through a fair share of crusted snow fields where abrasion is very high), and no noticeable reduction in cushioning. If there is a potential issue it might be the fact that the upper on the medial top of the right foot has a “wrinkle” that could develop into a high stress site and eventually a hole.

A “wrinkle” has formed on the right shoe on the medial top of the upper mesh fabric and may eventually lead to a hole at this higher stress spot. Only time will tell.

The “wrinkle” is not present on the left shoe so this is probably some sort of manufacturing issue. Whether it is common or not, only reports from other users will confirm. If my experience holds in observations of other such high stress spots in upper materials there will likely be a hole here at some point- the question is when.


The Salomon S Lab Sense Ultra is an excellent shoe for just about any terrain or condition one might experience. The midfoot support and overall cushioning along with excellent proprioception, grip, and acceptable weight lead to a “sweet spot” product for the trails. This will clearly be my go-to shoe for the 2017 trail running season for both training and competition. Stay tuned for another update- probably at around 700 km when I will have a lot more time/distance on the shoe in technical terrain.


The Haywire Heart – How too much exercise can kill you and what you can do to protect your heart – Review


There has been much written in the popular press over the past decade or so about the downsides of training for endurance sports particularly as it relates to the so-called “athletes heart”. In many of these articles (and as usual) the claims by medical “scientists” are often misrepresented, misinterpreted, and selectively presented to inflate any findings beyond even the typically overstated and often unsupported conclusions of the authors in contemporary medical journals including results from clinical trials. This represents a severe dis-service to the general population and specifically to those who choose to train for endurance sports.

The authors of “The Haywire Heart” dance the line between the constructive, by providing a useful source of guidance on the subject of arrhythmias and endurance sport, and the deconstructive, by adding further, in my opinion, to informational dis-service. I think they have stepped a bit too far on the side of overblown alarm and not presented a balanced, statistically framed, and critical context in which to absorb the significant body of research outlined and referenced in the book. The subtitle of the book is a particularly egregious alarmist and unsupported statement.

Of course, readers today gravitate toward sensationalism at the expense of accuracy and precision (it is not obvious why this is the case, other than the continued failure of our educational systems to address critical thinking skills, particularly in the US). As a result, if an author expects to reach any sizable non-fiction audience, nothing less than a muted sensationalism needs to be a central theme. In this, the authors of this book succeed. In providing a balanced, statistically accurate evaluation of the potential for the development of arrhythmias in endurance athletes, they fail.

The authors make a good start at a balanced approach in the introduction, but thereafter obvious bias and sensationalism creeps in and incrementally erodes the foundations of the “science” being presented. This process ends with a ridiculous chapter on “supplements”. Too bad because all of the elements of a very good guide to the subject are here and without the hype and misrepresentation it would represent a true contribution.

On the positive, the book will provide the reader with a reasonable description of the workings of the heart, the observed arrhythmias and various treatment options, and how the skimpy evidence on the effects of endurance sport training on the development of arrhythmias might be interpreted. The book is a worthwhile read provided one takes a critical stance on many of the conclusive statements throughout the book by pursuing investigation of appropriate referenced sources and applying logic, questioning “fact” , and using reason. Additionally, there is good coverage of what to be aware of as it concerns the symptoms that are typically observed in those endurance athletes who have developed arrhythmias- so if you are one of the very few who might be at risk you will have some idea of what sort of heart episodes to be sensitive to. In no way does the meager evidence for the incidence of arrhythmias that appear to be correlated with endurance sport exercise lead to any significant general concern for athletes training for endurance sports.

Although I am by no means an expert in the field of electrophysiology, cardiac arrythmias, or cardiac clinical research, I did spend 10 years of my scientific career on the device side developing new therapies and devices for the treatment arrhythmias. I have been intimately involved with development of state-of-the-art implantable pacemaker, defibrillator, and cardiac re-synchronization therapy (CRT) devices. In this work I interacted with Electrophysiologists, clinical researchers, and device experts to help provide the most efficacious treatments possible at the time. My background in the field is substantial, however I would not describe my level of understanding as “expert”.

As a research scientist I feel qualified to evaluate the scientific evidence presented and critically review any conclusive arguments and extensions to recommendations for endurance athletes. Additionally, I am a life-long endurance athlete who knows, trains with, and has raced against National-level and Olympic-level competitors for over 40 years- both when we were all “pink-lunged” youngsters and now as semi-decrepit Masters. In fact, many years back, as  budding road cyclist and graduate student doing research at Los Alamos, I would occasionally train with one of the authors (Lennard Zinn) up into the Jemez Mountains and around the Via Grande just above town. It was here that I first discovered my abilities as a climber and I am forever grateful for the “calibration” that Lennard supplied- he is a truly talented cyclist.

statistical context

Perhaps one the largest failings of this book is the complete absence of a summary of the observed incidence of arrhythmias in the general population and the common correlates and concomitant diseases that are associated with arrhythmias. As a result the reader is left to wonder what the expected occurrence rate of arrhythmias is in the general population and how this is related to age and other associated conditions.

Numerous epidemiological studies have been conducted on various arrythmias and particularly for atrial fibrillation since AF is the most common arrhythmia condition. The primary identified factor for the development of AF is age- the older you are the more likely you will develop AF. A recent study of AF in a European population showed an overall incidence of about 2% but this rate is highly dependent on age. The incidence at ages less than 49 years is about 0.14% but increases dramatically to about 4% at ages 60-70, and to about 14% at ages greater than 80. Additional studies of other populations typically yield slightly different incidence rates that are within error estimates. Other concomitant conditions include hypertension, obesity, diabetes, coronary artery disease, valvular heart disease, and cardiomyopathy.

With this type of statistical basis for the incidence, correlates, and concomitant conditions for arrhythmias, one is in a position to properly evaluate any increased incidence observed in endurance athlete populations. However, the book never reviews nor even supplies this information- which is very disappointing.

I have listened to a few of the podcasts that the authors have participated in and in those podcasts with Mandrola present it is stated by him, up front, that the condition is rare and any discussion should be cognizant of this fact. However, this never comes through in the book. Also in the podcasts, the significant uncertainty in making any concluding statements about the relationship between endurance exercise and the development of arrhythmias is highlighted. However, later in the podcasts, statements that are inconsistent with this are rampant.

the “athlete’s heart”

Fundamental to the all of the evidence and discussion on the development of arrhythmias in endurance athletes is a condition called the “Athletes Heart”. “Athlete’s Heart” is a syndrome described, in simple terms, by an enlarged heart and a low resting heart rate. Cardiac adaptation to endurance exercise and training leads to hypertrophy of (primarily) the left ventricle, dilated chambers of the heart, an associated increased stoke volume, and a generally attendant lower resting heart rate. These effects can be (and often are) misdiagnosed by uninformed (and often poorly educated) medical professionals as other conditions not typically found in the general population, e.g. cardiomeagly (enlarged heart), cardiac hypertrophy (thickening of the left ventricle), and bradycardia (low heart rate). Repeated loading of the heart muscle in ways typified by endurance sport training (e.g. long (>60 min) exercise  sessions and high intensity intervals) will naturally lead to cardiac remodeling that includes all of these conditions. One rare potential outcome of this remodeling is the (hypothesized) development of electrical malfunction within the heart which can be manifest as various types of arrhythmias and is the subject of the book.

It has been hypothesized that arrhythmias can be the result of endurance exercise via a mechanism that includes a process by which the heart muscle is taxed in such a way that it “stretches” and leads to small tears that are naturally healed by laying down collagen in the affected areas of the heart. This healing leads to something called fibrosis (aka “scaring”) and it is proposed that fibrosis can eventually lead to electrical discontinuities within the heart and manifest as an arrhythmia. There is no mechanistic understanding of the relation between cardiac fibrosis and electrical malfunction- it’s just an idea at this point. However, whilst reading this book you might be lead to believe that such a mechanism is fact.

alcohol use and atrial fibrillation

Although not central to the concerns about AF and endurance exercise, the following represents an example of selectively presented mis-information by the authors.

The authors present a graph (Fig 5.1) on page 130 that relates “chance” of atrial fibrillation with number of alcoholic drinks consumed per day, referencing a recent study  that has shown statistical evidence for increased risk of atrial fibrillation/atrial flutter for those who consume even moderate amounts (1-6 drinks per week!) of alcohol. Firstly, the graph is entirely misleading because the authors relate  a quantifiable variable (number of alcoholic drinks per day) with a qualitative variable they call “chance” of AF. Even though the referenced study presents a full analysis of the quantifiable data for the “chance” variable, the authors chose not to plot this quantitative information. This is a common method utilized by sensationalists to obsequiously over-state a relationship. This happens because a graph such as this shows, in this case, a doubling of the “chance” (or risk) for the ailment (in this case AF) per daily drink of alcohol but gives no information on the underlying risk magnitude. The underlying risk can be very low- as it is here. In addition the actual data on “chance” of AF used in the graphic is in units of risk ratio, i.e. total risk with alcohol consumption divided by total underlying risk. For there to be doubling of the risk this ratio would need to be equal to 2. It isn’t and this is detailed below.

If one analyzes the data presented in the referenced study it is found that the risk for the no alcoholic drink population is about 2% and that this risk is essentially unchanged for those who have about one drink per day, increases by about 10% (a risk ratio of 1.1) for those who have 2 drinks per day, and by about 20% (a risk ratio of 1.2) for those who drink 3 drinks per day. What this means is that the risk increases from 2% to 2.2% for those that drink 2 drinks per day. So although the obfuscating graph (and accompanying text) purports to show a doubling of the risk, it is not a doubling, and the magnitude of the increased risk, at least as far as I am concerned, is inconsequential. Make your own determination but, authors: please provide the data when it is available instead of confusing and obfuscating what is observed. The medical literature is rife with such drivel (see for example the papers by Ioannidis referenced at the beginning of this post).

The authors may have confused increased risk with increased incremental risk- which is a very different thing and one that the general reader would have limited interest in. Even if they meant to include the word “incremental” in front of “risk” (where appropriate) in this section, the data are inaccurately presented and is inexcusable in a book intended for a general audience. The relevant value is the increased risk- something that the reader can best understand and personalize.

For clarity a plot of the the risk ratio versus the number of alcoholic drinks per day based on data from the referenced study is presented below:

Risk ratio for the development of AF as a function of alcohol consumption in the general population based on data from a study referenced in the book “The Haywire Heart”.

A side note here that is good news to those who enjoy beer- the authors of the referenced study concluded the following as it concerns specific alcoholic drinks:

For specific alcoholic beverages, consumption of more than 14
drinks/week of liquor or wine was associated with
increased risk of AF (Table 1). There was no association
with beer.

It is not clear what to make of this observation other than this result highlights how little is known about the subject and any mechanistic cause that might increase the risk of developing AF. Since life stress is thought to be a contributing factor for AF, are wine drinkers more stressed out than laid back beer drinkers? Who knows… but the absorption of alcohol into the body seems to not be reliably associated with increased risk of AF, at least based on these data.

development of Arrhythmias in endurance athletes are rare

As noted, the incidence of arrhythmias correlated to endurance athletes is rare. In one long term study (reference 5 of Chapter 4) of about 52,000 cross country skiers who participated in the annual Vassaloppet 90km ski race in Sweden, an overall occurrence rate of less than 2% for all arrhythmias was found during the 10 year study period. Note that this incidence rate is similar to the results of the epidemiological study of just AF (not all arrythsmias) in a general population summarized above.

Apart from simple observations from incidence rates, it is important to point out that such studies are properly done by using exposure metrics rather than incidence rates. This is because the exposure (in this case, endurance exercise) is the parameter being studied to determine any correlated affects on the body. However, this exposure is confounded with age, a primary observed correlate with AF. Therefore the data are often presented in “person years” of exposure (in this case exposure to endurance exercise, not age, which is another type of exposure that confounds the data), as they are in this referenced study of Vasaloppet skiers. In addition, the models used to analyze the data employ techniques to correct the dataset for age and other concomitant conditions known to be present in individual subjects.  Using these metrics and modeling, the authors found an increased incidence of atrial fibrillation in the skier population that is functional with finishing time (a hazard ratio (instantaneous temporal risk) of about 1.3 among those with faster times) and number of races (a  hazard ratio of about 1.3 among those who participated in more races).

At this juncture, it is not, and cannot be, determined that AF and endurance exercise have any mechanistic connection. Any such connection is purely speculation. Additionally, there may be other, perhaps more important, factors (such as stress) not being measured that lead to the increased incidence of AF in this skier population. Since much of the data on health history and lifestyle factors (such as stress) is self-reported, significant errors are likely extant in the dataset. This is a fundamental issue with the results of all epidemiological observational studies (EOS) that attempt to link disease with exposure. This fact is never discussed in the book, yet much of the data presented derives from EOS.

Further, it can be pointed out that, even in this endurance athlete sub-population of cross country skiers, the incidence of AF is very low, however the authors of this book attempt to leave the reader (or at least this reader) with the impression that the condition is common among long term endurance athletes. The authors further reinforce this by using the anecdotal experience of one of the authors (Lennard Zinn) and making arguments that arrhythmias are much more common in endurance athletes- specifically, that an unexpected number of fellow long term endurance athletes known to Mr. Zinn came out of the woodwork after he was diagnosed and expressed that they too have various arrhythmias. Such expressed high incidence is just not supported by the (meager) data available, and, given the Boulder-centric observations, one might postulate that this supposed high incident rate of arrhythmias might best be called “Boulderythmia”- a disease that affects high strung, high stress, and “striver” male endurance athletes living in Boulder, Colorado.

This is not to say that an endurance exercise correlated arrhythmias is not a serious condition- just that it’s a rare one and one that is seen almost exclusively in older athletes just as it is (and at a similar rate) in the general population. The message here should be that arrhythmias are more common as one ages not that endurance exercise causes arrhythmias.

A critical editorial comment on the above referenced study of cross country skiers serves as a very well stated and concise summary of the state of understanding of any proposed relationship of exercise-dose with AF. The authors assembled data from numerous studies to come up with a exercise dose to risk of AF functionality. A “strawman” U-shaped graphic is provided but much caution is expressed as to the power of any of the current studies to allow firm lines to be drawn or even to establish guidelines with respect to exercise dose and the potential for development of arrhythmias.

Another recent review article by one of the authors of the comment is also a very good read (and where I learned a new (to me) word- pleomorphic – a word I am already itching to use!). Using a combination of these authors opinions, a review of the referenced work in the comment, and a critical review of the article will allow one to develop a substantiated position on the subject. Have at it!

Also recommended is a recent (2015) PhD thesis (an expanded version of the type of study in the article on cross country skiers referenced above) that has much more information and data. This study included 200,000 Vasaloppet skiers and a time frame spanning the years 1989-2010. Here is how the author summarized his work:

We evaluated risk of death during the race in two papers (I,II). During 
90 years of annual races, cardiac arrest occurred in 20 skiers, of which
five survived. The death rate is in average two per 100 000 skiers.

We also studied the association with cancer incidence (paper III). The
overall reduction of cancer was modest among skiers compared with the 
general population, but for cancers related to lifestyle the risks were
markedly lower.

We investigated the risk for recurrent myocardial infarction and found
a 30% reduction among skiers (paper IV). In paper V we showed that 
skiers with a first stroke have a lower incidence of all-cause death. 
The skiers had a higher frequency of atrial fibrillation but had less 
severe stroke and no increased risk of recurrent stroke. Thus our data 
suggest that a lifestyle with a high level of physical activity may 
work as a protection after a cardiovascular event.

Summary: The short excess mortality in endurance physical activity is
by far outweighed by the long term protective effect of exercise in 
cardiovascular diseases and cancer.

An overview of the thesis and an interview with the author is provided here and confirms the overall benefits of endurance exercise and the observed slight increase in AF. It seems obvious, based on the data available at this juncture, that the benefits of endurance exercise far outweigh any risk and this, combined with awareness of the symptoms of arrhythmias, should allow one to fully embrace an endurance sport lifestyle without any significant concerns about development of heart arrhythmias due to endurance exercise.


With the sensationalist approach of The Haywire Heart, it will take a bit of extra work and pursuit of clarification and calibration from the literature to fully grasp the current understanding of the relationship of endurance exercise to the development of arrhythmias. This is unfortunate because with some minor editing the book could have been a “one stop shop” on the subject for the interested endurance athlete and general reader alike. But the sensationalist vibe and biased writing undermine the good work that is presented.

The book does serve as a good source for basic information on the heart and how it works, review of some interesting cases of endurance athletes who have developed arrhythmias, and as a source for references to background material. I suggest you read the thesis referenced above and the other relevant work (including the recent review article) and make your own conclusions, but suffice it to say that, in my opinion, the alarm that is the apparent primary focus of the book “The Haywire Heart” is misplaced and substantially detracts from a book that provides an otherwise good source of information on the subject.