Tuesday, March 12, 2013

Gear Review: SLS3 FXC Compression Socks

Unless you've been living under a rock for the past couple years, you've noticed that compression apparel is no longer only for patients with circulation problems, and that athletes are now embracing the benefits of compression. And who can blame them? Increased venous return sounds good to me. Paula Radcliffe was the first athlete I noticed wearing the now-common knee-high socks, and anyone who somehow missed Paula certainly saw Chris Solinsky, when he wore compression socks during his record setting 10,000m run in 2010. (Btw, if you did somehow miss Paula's 2:15:25, watch it! Now!). Seeing as triathletes seem to love gear and toys (honestly, they probably adopted compression before runners, but since I don't pay all that much attention to the triathlon world, I can't say for sure), many triathlon companies began to offer compression socks and other gear. One such company is SLS3, who offer the SLS3 FXC Compression Sock.

SLS3 FXC Compression Socks are described by SLS3 as follows:
  • 20-30 mmHG of true graduated compression for increased blood circulation, muscle oxygenation, and stability
  • Mid sole air cooling channels for perfect moisture control
  • Left and right foot specific shape plus separate knitting zones for optimal fit
  • Seamless TekWeb technology to prevent blisters
  • Padding in pressure areas: Ball, heel, achilles, top of arch for shock absorption and protection
  • Antimicrobial fibers for odor control
  • Cooling effect and UV protection

Rather than me going into a dissertation on what compression does and doesn't do, if you're interested in the science, Steve Magness does an excellent job of compiling the research. To sum it up, the benefits of compression are increased blood flow and reduced muscle vibration. I'm not sure I buy increased bloodflow during activity, since your sympathetic nervous system and contracting muscles do a bang-up job of that on their own, but I certainly agree that increasing venous return (arteries are muscular and do a good job of pumping blood into the extremities, but veins are kind of wimpy and not as good at sending blood back to the heart) and reducing blood pooling in your legs after running can speed recovery. As far as reducing muscle vibration during exercise...well, anecdotally, I wore RecoFit Calf Component sleeves for the Philadelphia Marathon, and while I did get some calf cramping during the race, my calves were not nearly as bad as I expected them to be in the following days...probably comparable to the day after the first race in spikes, and they weren't nearly as trashed as my quads.

SLS3 FXC Compression Socks

Compression is measured in mmHg, which is a measure of how much pressure is exerted on the tissues, so basically how tight the socks are, with higher numbers equating to more pressure. 20-30mmHg is considered firm compression (higher compression usually requires a prescription and is reserved for people with circulation problems, such as DVT, and too much compression can cause a tourniquet effect and actually limit bloodflow), and it seems to be right around the sweet spot for recovery and on the more compressive side for actual running. I'm not certain the FXC Compression Sock is actually 20-30mmHg, because it's not quite as compressive as the pair of Zoot ULTRA CompressRx socks that I own which are rated at 18-30mmHg. However, I've found the compression to still be fine for recovery (though I do prefer the Zoots for the days where I'm really sore), and not being super compressive is probably a good thing if you plan to run in them (IMO they're better for actual running than the Zoots). The toes on the SLS3 are also less super-squeezy than the Zoots if you're one of those people who don't like your toes squeezed. Finally, they're left-right specific for targeted compression.

Additionally, FXC Compression Socks offer graduated compression, which means they are tightest around the foot and ankle and pressure gradually decreases as they move up your leg. Graduated compression is what most quality compression socks are offering today. Graduated compression also becomes extremely important if you're using these socks for recovery, as opposed to only while running. This graduated compression is quite noticeable compared to some other socks I've worn, and they're noticeably tighter around the arch of the foot and ankle than the upper calf.

FXC Compression Socks aren't quite as difficult to get on as some other compression socks, possibly in part due to the graduated compression, which makes getting the upper part of the sock over your foot much easier. This probably makes them a better choice for triathletes who want to race with compression, but would prefer a full compression sock to sleeves under their wetsuit. Once they're on though, they stay in place, and I haven't had any issues with them sliding down. However, if you're on the edge as far as sizing, I'd definitely recommend going with the smaller size (as opposed to the aforementioned Zoots, where I'd probably recommend going to the larger size).

FXC Compression Socks are on the tall side (definitely taller than the Zoots and taller than the Pro Compression Marathon Socks), so they may be a good choice for taller people. For shorter people, I just kind of leave them bunched up right below my knee...it doesn't really bother me, but I figured I'd mention it if you're around my height (5'3, not having particularly long legs for my height, and wearing the XS/S size), and you really don't like your socks bunching up.

The sock itself is of a medium weight. For me, that means it fits fine with my trainers, which I wear a little looser than my racers, but is a tight squeeze with my racing flats, which I generally size for a performance fit with either sockless or with a very thin sock. Your mileage may vary based on your typical sock and shoe sizing preference.

FXC Compression socks are made of a technical fabric that SLS3 called "Micro-Nylon." Whatever it is, it's comfortable, I like it. They can get a little hot, but if you manage to find a compression sock that doesn't, please let me know. In my opinion, if you're racing in hot temperatures and absolutely want compression, you're better off with a lightweight sock (or no sock) and a calf sleeve than a full compression sock.

For washing the FXC Compression socks (as well as other athletic compression socks), I generally wash them on delicate and let them hang-dry. It is recommended not to put these (or any garments containing lycra) in the dryer. Washing them also serves to restore compression, since wearing any compression sock will stretch it out. Please note that this is for athletic compression socks...if you somehow got to this blog and are looking for instructions on washing prescribed compression for a medical condition, please ask your doctor. Sometimes those require special washing instructions.

Sizing information is available on the company's website, and sizing according to both calf circumference and shoe size is available. If your calf circumference and shoe size don't match up, I'd highly recommend going by calf circumference, since that's generally the more accurate way to size compression apparel. Calf circumference is measured at the widest point of your calf. If you don't have a flexible tape measure, wrap a piece of string around the widest part of your calf, then straighten it out and measure its length with a normal ruler.

SLS3 FXC Compression Socks

SLS3 FXC Compression Socks are a solid contender in the compression sock market. I'd particularly recommend them for triathletes and for tall people, as well as for those who prefer a sock that's noticeably more compressive at the arch of the foot and ankle than at the upper calf (especially those who are using this sock for running rather than just recovery, and want a little more give at the calf, or for those with particularly muscular calves).

SLS3 FXC Compression Socks retail for $54.90 and are available on the SLS3 website. They're available in both black and white, as well as in a pink or blue butterfly colorway. SLS3 also offers calf sleeves for $44.95 for those of you who prefer to wear a certain type of socks when running.

Full disclosure: SLS3 FXC Compression Socks were provided by SLS3 free of charge in exchange for a review. The opinions contained in this review are mine and based on my experience, and do not reflect the opinions of SLS3 or anyone else.


  1. Thanks for the info about compression socks. I had already read the post of Steve Magness about this kind of socks and I agree with his conclusion. As for me, I find them helpful especially while running and even while travelling. I also love the variety of colors and designs I could choose. I love pink and printed and I often buy online at Legs Therapy. :)

    1. Thanks for your comment! I tend to agree with Magness too, and mainly use them for recovery...though they do keep your calves warm when it's too cold for just shorts but you really don't want to deal with tights! :) (That's actually the original reason I used them at Philly, and the less-than-expected soreness ended up being a bonus). It seems like some people get performance benefits out of them though, and whether it's placebo or not, any benefit is a good thing!

    2. "...whether it's placebo or not, any benefit is a good thing!"

      Aha, and the good thing is many benefited from it, not just runners but even travelers and people with diabetes. :)

    3. Oh yeah, I definitely wear compression socks when I'm traveling. I am not up to date on the research as far as compression and DVTs, but I feel like since you're sitting in one place and your legs aren't moving much, it's good to have something aiding the venous return back to the heart.

  2. Please do not put any garments containing lycra (or the generic counterpart spandex) in the dryer. Heat, bleach, chlorine all destroy the lycra fibers much faster, sometimes after one dryer cycle, and then the socks are shot and the compression gone.
    Our care instructions advise this, and I believe any competitive products as well as swimwear, tri and cyclewear companies have similar care instructions.
    Happy wearing, Sylvie Linke, Owner SLS3

    1. Thanks for the heads up! I've edited the review to reflect this.

  3. If your job requires you to sit or stand in the same place for extended periods of time, wearing compression socks are very beneficial.

  4. So informative things are provided here, I really happy to read this post, I was just imagine about it and you provided me the correct information I really bookmark it, for further reading, So thanks for sharing the information.

  5. This is very informative blog. I just want to know that are they same as diabetic socks.

    1. To be honest, I don't know if the compression level is the same or not. That's an area where you'd want to consult with your doctor.

  6. Thanks for the nice post. I always like these types of physical events particularly the wears like compression sleeve, wetsuit, sports bra and other sports wear. This is really awesome.


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