What’s the best indoor training device for XC Skiing? Part 1: ThoraxTrainer

In this 4 part series, we compare the Thorax Trainer, Concept 2 Skierg, and the Ercolina trainer in addition to giving you our recipe for success for summer training.

The universal restart button for nordic skiers is typically May 1st. I’m already exhausted from scrolling through athletes I follow on Instagram trying to “one-up” each other with the latest training post, video, etc. It seems everyone has a ‘plan,’ and they are oh so eager to start and follow it to a ‘T.’ My take on May being the arbitrary starting point maybe deserves its own editorial, but I can try and at least tell you my personal athletic actions at this juncture.

Here at the Seder-Skier Training Headquarters, the Shovel Lake Nordic Ski team has not yet fully considered the training year to start. Oh no. 2019-2020 isn’t in the books. Sure, we are done racing, and we would be even if CoVid-19 wasn’t a thing. But to us, the post-season is a special time where training is guided by a unique compass: the “joy of skiing barometer.” That means staying on snow as much and as long as possible. After all, skiing is good, more is better, and since we didn’t start until 2018, we have a large deficit of lifetime miles to account for.

As we continue to chase snow (and we don’t have to work to hard here in Leadville) for what will soon be the 200th day of the season (Oct 21st to present), my thought is that May is a special “bonus” time to log hours, practice technique, push limits physically, and enjoy the sport of skiing. Staunch followers of a physiologically dogmatic approach might scoff at our style, but lets be honest – it’s MAY!. We want to be sharp like, literally 10 months from now….There will be plenty of time to have specific tests, key workouts, rest days, etc. This is the time we like to just ski and let our bodies and our hearts tell us when we need to back off or when we can try and scale a summit crust skating.

I digress…

So, while Shovel Lake Nordic’s members are continuing to enjoy 2019-2020 and our special post-season phase of the training cycle, most people are already diving headfirst into preparations for 2020-2021 (and my goodness, we better actually have a racing season, right?).

That means rollerskis, running, time in the gym/weights, and also (cue: “DAH DAH DAH” music) ….the indoor cross country ski trainer. In the industry, three specific brands have held center court for skiers trying to maintain and/or test fitness during the tricky transitional phases of the season, namely the rain and slush we often contend with from October to November or May to June: The Concept2 Ski Erg, the Thorax Trainer, and the Ercolina Trainer.

In this series, we’ll provide all of the facts you need to decide just what device is right for you. Even more, we discuss the history and development of each company, compare scientific research which has utilized the different brands, and, for those who maybe aren’t ready to commit to an indoor trainer purchase, give you some other “must haves” for making this off-season the one where you take “the next step.” By the end, you’ll at best be soundly educated on off-season tools, and at worst … or best, depending on you look at it, be convinced to move to a place where there is no off-season!

On the docket today:

Thorax Trainer

Quick Facts – from http://thoraxtrainer.com/products/thoraxtrainer/

Cost: 1,600 Euros – excl. VAT

Comes with: Thorax Trainer, finger touch computer (Time, Watts, Speed, Distance, Heart Rate, Calories, Frequency and derived variables; pacer function and interval training), adjustable ski poles, 2 year product warranty (machines and computer) 1 year breakage warranty on the poles; 3 month warranty on straps and handles)

Location: developed in Denmark


Length: 259cm

Height: 36 cm

Width: 71 cm

Weight: 32 kg

Material: Aluminum and Stainless Steel


ThoraxTrainer Ltd. was founded in 2008 by a medical doctor and engineer, both whom had elite careers in triathlon and cross country skiing. With a desire to bring the world’s toughest sport indoors, they worked to develop the first ski ergometer which “realisitically could imitate Nordic skiing.” They sent their first prototypes to the Olympic training centers in Norway, Sweden, and Denmark, and upon receiving high praise from those places, proceeded to bring the product to the general fitness industry.

I first ran into the ThoraxTrainer while sifiting through scientific journals. Common practice for ski research is to use a “modified ski erg” to collect reliable and controlled upperbody poling data. One such study, conducted by current Bowdoin Head Nordic Ski Coach Nathan Alsobrook, even included a picture of the device, seen below. If you want to know the story about that device and its usage in Alsobrook’s study, be sure to listen to our next podcast, where we sat down with the former MSU Bobcat researcher and picked his brain on the ski specific research lab run by Dr. Dan Heil in Bozemon, MT.

A screen shot of the MS Thesis of Mr. Alsobrook, who is demonstratin the modified ski erg.

AS you can see, a “modified ski erg” is essentially a Concept Rower with poles attached to runners. Alsobrook’s study was published in 2008, but similarly designed modified ergs were in use before then elsewhere in the field of sport research. We reached out to ThoraxTrainer for a comment on the specific development of the product and any possible relationship between it and the modified ski ergs seen in sports research during this time, and we did not get a response. However, I would venture, given the sports science background of the developers, that they quite possibly had in mind that what they were creating with the Thorax was a nice machine for both research and recreational/general training purposes. Just a gander.

early work on the ThoraxTrainer (source: http://thoraxtrainer.com/about-thoraxtrainer/#)

In addition to being used by elite nordic skiers as a ski specific training device, gyms across the globe have used the ThoraxTrainer as the centerpiece for implementing unique and highly effective training programs, which you can watch on their website. These are “Strong-Body,” “Core-Circle,” “Ski+Shoot,” “Ski+Bike,” and “Ski+Run.” In essence, each of these models involves alternations between specific exercises on the ThoraxTrainer with another mode of intense exercise. In the “Ski+Bike,” for instance, participants alternate skiing and biking. “Ski+Run” is similar – skiing and running (they list this as the most difficult.) Obviously, these models require the individual or gym to have the necessary equipment (treadmills or stationary bikes).

Wondering what “Ski+Shoot” is? Well, alert Russell Currier up in Stockholm, Maine, because that alternates a ski interval on the Thorax with laser gun target practice. Biathlon practice for everyone! I actually think this might be the way to get the video game generation hooked on exercise. The concept is pretty neat – but I could not find information on the website about where you can by the targets and gun. It simply says to “contact” for purchase information.


While one could reasonably argue much of scientific research completed in the field of nordic skiing has used a ThoraxTrainer model/concept, you can also find current research which outlines training effects on elite and general populations using the current and actual ThoraxTrainer equipment and training methods. In fact, 9 universities in Europe and the US have used ThoraxTrainers with projects involving elite athletes, rehab projects, and senior exercise programs. You can find their results here: http://thoraxtrainer.com/academy/research/

My quick take: this is a product that has been shown to be very effective for a wide range of specimens. Nordic skiing stresses the body on many fronts – balance, cardio, muscular strength, power, etc – and it appears the ThoraxTrainer, by effectively brining the sport safely to people indoors, has allowed a much larger portion of the population to reap the fitness benefits others enjoy while pursuing the sport in its natural environment. Thanks in large part to its versatility in exercises (15-30 different movements can be performed on the device), gains are not just seen in “upper body poling” metrics, but rather, as the study with industrial workers in Germany in 2014 shows, balance, sit ups, push-ups, and ThoraxTrainer distance (which we could consider ‘aerobic/anaerobic fitness’ in this case) also improved when training 2×6 minutes a week for 8 weeks. That is not much training at all for that type of improvement.

I felt a closer look at the study involving triathletes may be warranted. Participants improved over 200 seconds in a 3k time trial after the 12-week training program. To me, an improvement of over 3 minutes and 20 seconds in a race which is shorter than 2 miles means the overall ability of the runners maybe wasn’t all that high to begin with. Or, the first 3k was done in the mud running uphill in Ireland, and the second was done on the notorioiusly fast and possibly short indoor track at Boston University. We are told, however, the six athletes in the study competed in and set personal bests in Ironman Copenhagen in 2013. I’ve never done an Ironman and I’ve heard you have to be decently fit to do one. 🙂

One final study we found when scrolling through the ski+shoot files; this one has more nordic specific implications:

A research project by the University of Umea shows a correlation of 0.96 between ThoraxTrainer and cross country skiing. “In other words, you can predict your performance on skis based on your ThoraxTrainer performance with 96% accuracy.” (source: http://thoraxtrainer.com/?s=ski+shoot)

The Seder-Skier verdict

Price: B

In a way, the ThoraxTrainer is the most expensive of our three products. The Ercolina can be cheaper, since you don’t need the computer, but if you do buy one (and most likely would), it actually sits at the top of the price chart. So, for what you get – poles, computer, the machine itself – this is a decent deal. But, 1,600 euros isn’t quite cheap enough for me to say its a steal.

Design: B-

This one is hard for me. You could argue this design is the best because it most closely resembles actual skiing. Also, the addition of a lower body element would most easily be developed and put in place on the Thorax. However, I consider those advantages in the next section. It seems that because of this very priority, practicality in terms of size, shape, storage ability, and general risk of wear and tear is sacrificed.

Because there are a lot of different parts, one would presume a greater potential for wearing out or breaking. The sliding mechanism for the poles and the poles themselves are two that immediately come to mind. In terms of storage, unlike the Ercolina, which can hang from a tree or be hidden on a shelf, or the SkiErg, which can be mounted on a wall or disappear in a closet, the Thorax is a built larger, longer, and thus is a bit trickier to store and probably more susceptible to simply being crashed into. If you have one of these, you really would need a room dedicated to training. Simple as that. It’s not something you can wip out on a dime like the ShakeWeight. Of course, the SkiErg is not that portable either. This is really where the Ercolina separates itself.

Sport Specificity: A-

Nothing is perfect, but this comes the closest, and it has the research to back it up. This is where the criticisms from above can come back with some teeth. Larger, longer, akward with poles? Sure. Does that increase its ability to be a more specific training device? Yes.

Versatility – B+

We give ThoraxTrainer credit for showing us all of the different motions, exercises, and body regions we can hit through their youtube videos and programs. Props for the ingenuity. Don’t try some of those exercises on skinny skis and snow though …I don’t think they carry over.

Again, in pointing to the research, ThoraxTrainer has shown that it isn’t a one trick pony product. Many different populations and gyms are incorporating the product into training programs with great feedback and success. If you don’t believe me, read some of the reviews and quotes from physiotherapists, athletes, and gym owners posted on their website.

Who is it for?

  1. The serious nordic skier who has the space to devote to this type of training. If you don’t travel a lot during racing and training seasons, this would be ok. Like for me, I’d love to plant one of these suckers in the basement of my parents lake cottage in Minnesota. I know I’m going to be there in the summer, and I can’t imagine a better way to wake up than double poling to Loon calls while watching a crystal clear glass lake. It can just stay there and wait for me to use every June and July.
  2. Gyms – a room full of 6-8 of these is epic. The HITT workouts they can come up with are awesome and effective, short but fun. Everyone wins there.
  3. Training Centers and Research Labs – I could picture an Olympic Training Center or high end club team deciding to go with the Thorax for a few reasons. First of all, it gives them the best device for conducting research. While the Concept SkiErg has a wide user base, making comparison of data and 1k TT’s fun, if you want to conduct nordic ski research which involve UB power, you either buy power meters in your ski poles (future podcast…stay tuned when we talk to SkiSens), modify a Concept ala Montana State University, or go with a professionally designed modified SkiErg, which is your Thorax. Places like SunValley, which operate as both a training facility and a research lab, would definitely benefit from a device like this. Or, the High Performance Center in Park City for the USSA. Ercolina’s are great for the road, SkiErgs are great for your home, and Thorax’s are great for the lab/gym.

Why would I get this instead of the SkiErg or the Ercolina?

ThoraxTrainer separates itself, I would say on two things: First, it is uniquely sport specific with its usage of actual poles. Second, because of this, the computer data is more valuable. Not only for research, but for gauging and predicting actual ski performance, the ThoraxTrainer holds a slight advantage.

I’ve never actually seen or used one of these things in person, so take what I say with a grain of salt. If I were to invent a ski trainer, this is probably what I would have designed. May favorite aspect, just in looking at it, is that it seems the closest to fully replicating classic striding. I hope someone works to develop a realistic feeling lower body action, but I suppose I shouldn’t get my hopes up too much.

Questions, comments, opinions? Let us know by commenting below.


Published by rsederquist

My name is Ryan Sederquist.  I am a man of many passions and dreams, and this website is the outlet for many of them. I am currently teaching 5th grade remotely in the Adams12 school district in Colorado. I have been an elementary music teacher in Alamosa, Colorado, as well as a 7-12 band director at Lake County High School in Leadville, Colorado. I am also in the final, final stages of acquiring my M.S. in Exercise Science from Adams State University. In 2018-2019, we spent a year in Presque Isle, Maine as I coached the UMPI Nordic ski team. I currently live in Leadville, Colorado with my wife Christie, a special education teacher, and our border collie-German shepherd mix, Ajee. Even though it is not my full-time job, ever since I was a child, I had the desire to do one of three things professionally - pro sports, writing about pro sports, or being a radio talk show host. This website is where I pretend to do the latter two, and when I'm out pretending to do the former, I listen to podcasts, think about topics, and pursue my wild dream of someday, at some event, in either running, biking, or skiing, wearing a team USA uniform. This website contains articles, podcasts, pictures, and journal entries that have to do with my passion and involvement in endurance sports. Our flagship project is the Seder Skier Podcast, which talks mostly about nordic skiing and attempts to interview influential individuals in the ski world. I also rant about the Big 4 sports, with a lean towards Minnesota teams (Vikings, Twins, Twolves, and MN Distance Running). I sometimes try to write Sports Illustrated like 'feature' articles about athletes as well. In addition to a focus on sports, you will find the occasional article or show that discusses the intersection of theology and society ...which is ...obviously everywhere. We place these in our Skieologians podcast. The heading at the top of my homepage reads, "Search for Truth. Play with purpose. Strive for success." It is the underlying theme for my coaching philosophy, which can be downloaded from this site. Basically, I'm always looking to search for the truth in my pursuit of knowledge, whether that is knowledge regarding the best methods for waxing skis, training a quarter miler, or defending my Christian apologetic. Searching implies a dedicated pursuit for knowledge, and that is what I'm about and what this site is about, even if it is simply for providing viewers with an accurate description of a product. Play with purpose has to do with living out our passions because they are fun. I ski because its fun. I play music and teach young kids because there is joy in it. This blog is about celebrating the joy and fun that inherently exists in the pursuit of excellence and in the activities themselves. Finally, strive for success is built on the principle that true success is the realization that we gave 100% effort to become the best that we could possible be. It requires 100% in preparation, competition, reflection, mental effort, etc. If something is worth doing, I believe it is worth doing with that level of effort. Someday, I hope to race the Visma Classics - the entire season, wear a Team USA singlet, and have a job that involves writing or talking about sports or theology all day. If you know of any body I can reach out to to help me accomplish these goals, please email me at sederquistrd@grizzlies.adams.edu

2 thoughts on “What’s the best indoor training device for XC Skiing? Part 1: ThoraxTrainer

  1. Very interesting article, Ryan! I would like to see a video of one of these in action! Not sure we have room in the basement at the lake but if I could try one and do it I might share the cost with you and the storage. What is the price in US dollars?

    Liked by 1 person

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