A lot of people want to know what we mean by CLAC and how to do it on the kBox. It’s short for Concentric Load Acceleration Cycles, and those who have tried it wish they never did.
Joke aside, CLAC is the invention of a friend of Exxentric’s, the American world class rower Andy Baxter. Put simple, CLAC is a method for getting dynamic, fast and overloaded eccentric actions coupled with maximal concentric actions. This means high forces, hard work and little rest.
The thing with eccentric resistance training is that you are stronger in the eccentric phase and hence you can overload that phase with about +30% compared to your 1 RM concentric with a range of 20-60% (1) . Overloaded eccentrics (ECC+) are very efficient in building mass and strength (2) and way superior to traditional CON-ECC training. ECC+ training is also efficient in performance improvements in already trained subjects that often can get stronger with resistance training but are having difficulties improving performance (3).
Since regular CON-ECC in flywheel promotes hypertrophy about x2 compared to the same exercise with traditional weights (4) you can start to imagine what would happen if we start doing ECC+ on flywheel devices like the kBox. Yes – gains, gains, gains.
Apart from the dynamic load of the flywheel you can also get fast eccentrics compared to the slow supramaximal lifts with a barbell. Overloaded squats with a barbell is a quite dangerous and very slow activity. You need spotters and will do probably one rep and rest a couple of minutes. Pretty far from your sport activity, if you aren’t a powerlifter or strongman.
Done on a kBox you can get overloaded eccentrics in a much faster pace and work more dynamically, get higher metabolic demands, get higher forces and more muscular tension and work in much more sport specific velocities. CLAC is the ideal eccentric overload method to achieve all of that. Having fun is optional.
The fundamental CLAC concept is to create a series of three consecutive actions consisting of 100% CON and 130%+ ECC, followed by 100% CON. The 2nd ECC phase is with low load going back to starting point. Obviously this requires decreasing the resistance for each rep to adapt to the increasing fatigue of the user. Using a versatile flywheel device such as the kBox, CLAC can be done easily with a variety of excercises, particularly in the upper body.
Let’s take biceps curl for example. You start a concentric action with accelerating the flywheel with your lower limbs, with a squat action. When legs and hip are extended you start curling. At the end of the concentric curl you will have all energy from the curl and the squat in the spinning motion of the flywheel. In the eccentric phase you only do the curl while resisting the flywheel fully and then get an overload eccentric action. In the bottom of the curl, still in a standing position you do a 1 RM curl and then get an easier phase when you go down into the squatting position again.
Progression is Key
What about DOMS then? well, it would be a mistake for a newbie or even an athlete to start doing complete CLAC sessions. Honestly I don’t understand why you would begin with eccentric-only sessions at all. The key is progression. You don’t have to get DOMS to get a positive effect. Start with a set of CLAC in one exercise, say like curl, high pull, military press or bent over row. Add another set in another exercise the next session or within the next week and go on. After a while you can throw in 1-2 sets of CLAC in all exercises in your scheduled workout and get the expected results and be back without long periods of DOMS.
Another option I use myself from time to time when there just isn’t time to workout is finishing off a regular set with 2-3 reps of CLAC in the end. In a compact program just going through 7-8 exercises at 100% intensity for 7-8 reps with CLAC in the end of each set will take you about 4-5 minutes on the kBox and is easy to squeeze in a busy schedule. It’s hard for me to find any more effective 5 minutes spent in a gym that is paying back more. More about this in future posts, promise.
Finally, some quick tips for eccentric training.
- 1. Do eccentric, preferably overloaded actions (ECC+). They are more effective.
- 2. Mix it up in your regular training. Don’t do complete sessions of eccentrics.
- 3. Start with one ECC+ or CLAC set in one exercise.
- 4. Add another 1-2 sets every week in another exercise.
- 5. Use kBox for the most dynamic, safest and most sport specific training.
And of course, heavy resistance training requires:
- 6. Don’t do heavy training when you don’t feel well or aren’t restituted.
- 7. Warm up properly.
- 8. Eat clean. More veggies, more proteins, less sugar.
- 9. Sleep eight hours.
- 10. Don’t hold back on the coffee, it attenuates DOMS and the associated decrease in force. (5)
/Fredrik Correa, M.D., co-founder
- 1. http://www.ncbi.nlm.nih.gov/pubmed/17313264
- 2. http://www.ncbi.nlm.nih.gov/pubmed/25048074
- 3. http://www.ncbi.nlm.nih.gov/pubmed/19937450
- 4. http://www.ncbi.nlm.nih.gov/pubmed/17926060
- 5. http://www.ncbi.nlm.nih.gov/pubmed/17161977
I was recently involved in a discussion about the suitability of flywheel training and eccentrics for youths, and I realised this might be interesting for anyone involved in coaching younger athletes.
Should a young person use the kBox? First of all, the kBox is a multi-purpose device. You can do exercises with different relations of loads in the concentric and eccentric phases, including eccentric overload, depending on how you use it.
Football player in the elite youth team of Swedish football club Djurgården IF doing kBox squats.
Youth players’ first experience with weight training shouldn’t be eccentric overload but of course they can do resistance training for which the kBox is very suitable. There are a multitude of benefits, such as lower risk of collision, low noise, low torque on the lower back, ease of limiting depth, variable resistance and so on.
Resistance training in youths has been proven over and over to be beneficial. Kids who do resistance training get less injuries in every day activities, including sports.
On the sports performance side I just got hold of a paper from a study conducted in the UK (Low et al. J Sport Sci. 2015) where they tested the effect of repeated sprints after heavy barbell squats. The subjects were 17 years old youth soccer players. After testing of 1 RM in squat (the strongest boy squatted about 140 kg) they did reps at 91% of max before repeated sprints and their total sprint time was significantly reduced after the heavy squat. This action is rather soccer-like with repeated sprints.
This is just to examplify that these types of exercises are already being done in sports and that it is improving performance. So why not offer them a better tool to accomplish this? There are other studies where increased strength in squat in youth players have shown to improve sprint time and max speed and so on.
From a personal perspective as a former ice hockey coach I have good experiences with weight lifting. In my former club we started with Olympic lifting at age 12 and by age 16 my team competed in the national Olympic lifting league for youths (and we actually won a competition once).
Our weight training with kids and juniors in that club was also what made us start to develop the kBox. We wanted to further improve both effectiveness and safety in training in youth sports. Lately we have done similar things, for example at the training camp of the Swedish national youth team in alpine skiing (see video). They went all out on the kBox and it worked great. Even a boy with a broken shoulder could do kBox squats thanks to the harness! Another great experience was an elite youth soccer team in Stockholm with 16 year-olds who did kBox training regularly during the season with no problems at all. However, as with all training, weight training is dependent on progression. As I wrote above you should build up a basic strength before you start doing eccentrics.
For these reasons, I think a lot of youth players at all levels can benefit from the advantages of investing in flywheel training on the kBox. Have you tried flywheel training with youths? We would like to hear and share your experience.
/Fredrik Correa, M.D., co-founder
/Erik Lindberg, CEO Exxentric
It was with great sadness that we noted the recent passing of legendary physiologist, professor Per-Olof Åstrand of the Karolinska Institute in Stockholm, one of the pioneers of modern exercise physiology.
Our co-founder Mårten Fredriksson, an olympic coach focusing on strength and conditioning for ice hockey, had the privilege of meeting professor Åstrand many times, developing a warm friendship. Here are his personal memories.
I met P-O Åstrand for the first time during my first semester at the coaching program at the Swedish School of Sport and Health Science (GIH). It was the autumn 1998 and he held a lecture about the emergence of exercise physiology from the 1960s onwards. I remember him mentioning that in the mid 1960s and early 70s…
- human skeletal muscle biopsy had just been introduced
- the first studies related to diet and physical performance were yet to be published
- there were no discussions of fiber types or the effects of training and deconditioning on the enzyme systems, capillary density, and myoglobin concentration
- there where no papers dealing with the relationships among exercise, fitness or osteoporosis
- the terms anabolic steroids and strength training were not combined
- the first report of blood doping appeared in 1972
The first “lecture” I held myself in P-O’s presence was when the ice hockey team Toronto Maple Leafs visited Stockholm for a training camp and their strength & conditioning staff came to GIH. I talked about applied sport science for ice hockey and the topics were concurrent traning, cross traning and hybrid training. Afterwards P-O told me that he had held a lecture in Toronto about exercise physiology at the Third International Conference on the Coaching Aspects of Ice Hockey in 1976, when the Canada Cup was played. Later he gave me cufflinks in gold with red maple leaves on which he had been given as a specially invited guest. As a fan of ice hockey I keep these along with my medals from different world championships and the Olympics 2006 when Sweden had both gold and silver for men and women respectively. I appreciate the cufflinks as valuable as the medals! Later, in the summer of 2011, P-O gave me a signed ice hockey stick from the players in “the big red machine” – CCCP – from the 1970s. I could just say wooow!
During his long and rich life P-O traveled around the whole world and contributed tremendously to the progress of sport and health science. As late as the week before Christmas 2014, he visited GIH and attended the closing dinner with students who took their exams.
Many many thanks and rest in peace P-O Åstrand! You have always been an inspiration!
Marten studied Sports Science at the Swedish School of Sports and Health Science in Stockholm (GIH) with focus on ice hockey. He has worked as an ice hockey coach for over 15 years with teams on the highest level and also participated at eight world championships and two olympics (juniors/seniors/male/female) as strength & conditioning and video (tactical) coach.
Marten is now a lecturer at the Swedish School Of Sport & Health Science (GIH) and a laboratory instructor at the laboratory of applied sport science at GIH, as well as a co-founder of Exxentric.
2014 saw inceasing numbers of professionals using flywheel training around the world and growing scientific support for flywheel methods.
For Exxentric, it has been a successful and eventful year, with more new customers around the world than ever and a successful launch of the kBox 3. Here is a recap of our year and an outlook at 2015, by our co-founder M.D. Fredrik Correa.
2014 was an intense year. Among our best experiences was starting a new tradition with the Exxentric Summit in Stockholm in May with participants from all over Europe. Our distinguished guests made it a very fruitful couple of days. We made many new friends and got new ideas for coming products and improvements. Afterwards we got a lot of positive feedback and, yes, we aim to make this a recurring event.
We also moved into the US market with a new local distributor as well as a reseller. It feels great to now be able to serve all the US athletes, coaches and institutions interested in flywheel training. In a short time our skilled partners have spread the concept of flywheel training widely in the US and connected with lots of great people in our field. The step to enter the US has also made a big impact as several articles about flywheel training on the kBox have been written by some of the very best strength and conditioning coaches, Chris Korfist and Carl Valle. We were even asked to write an article presenting our story and our concept of training in one of the most influential blogs for track and field coaching.
As you might have noticed, at the beginning of December we launched the highly anticipated kBox 3 and started shipping it, initially to partners and key users. We are thrilled that so many of you have appreciated the improvements that we have been working hard with during this year. We believe that the new kBox 3 has set the standard for closed chain, multi-exercise flywheel devices with its increased versatility and ease of use.
During the first weeks after launch, your demand for the kBox 3 even outstripped our production pace. From January 2015 we will be going at full capacity at our new production facility in southern Sweden in order to minimise your wait for delivery.
On the scientific side we have seen growing buzz about flywheel training and eccentric training during 2014. We were overwhelmed by your interest in the article we shared showing the huge increase in start speed for swimmers who made flywheel lunges first (the Post-Activation Protocol). Articles and pods covering the topic of eccentric training are also coming at a steadily increasing pace, and we have started to share the best of them with you on social media (including our Facebook and Twitter profiles). Also, we’ve been really proud about all of you kBox users who are sharing images and stories about your flywheel training. We try to share and pass on as much as possible. If you tag your posts with our name we’re sure to find it (or use hashtags such as #kBox3, #flywheeltraining or #exxentric). Our prediction is that you will read a lot more about flywheel training in 2015, as researchers, coaches, athletes and personal trainers realise its potential when you want to get effective eccentric training in a safe way.
As we look forward to 2015, we have many things to get excited about. For example, in the not too distant future we will present you with an app-based and wireless feed-back system for the kBox! I can’t tell you much more about it but it is being tested right now in real training situations and will be launched in 2015. To the right you can see a preview of an early version of the app. The solution will be backwards compatible, so all earlier kBoxes with a SmartCoach sensor will be compatible with this new app solution. SmartCoach continues to be the tool for the professional coaches among you, while the app is developed to enchance the experience for those of you training on the kBox yourselves.
Also, as some of you already have seen, we’ve started to rework our web site, and there’s more to come. On the product side you have given us lots of ideas for development, and our ambition is serious. I can’t go into specifics but we can tell you that our R&D department has got a heavily increased budget for 2015 thanks to your increased interest in the kBox. This increase is aiming at presenting new products as well as accessories during 2015, so stay tuned!
Wishing you all a Happy New Year!
/Fredrik Correa, M.D., co-founder
Following the huge interest in flywheel training from Chris Korfist’s article on the subject in the leading blog Freelap USA, the editors became so intrigued with the concept that they asked us to write our own article about it. We were honoured, as Freelap USA is one of the world’s most influential training blogs for track and field, and top coaches around the world read every article that gets published there.
Our co-founder, M.D. Fredrik Correa accepted the invitation and our story was published this Wednesday. The article was quickly shared widely in professional coaching circles on social media. You can find it here: What Every Coach Ought to Know About Flywheel Training.
Today, we have proudly started shipping the kBox 3, the newest version of our versatile flywheel training device. Here, founder Fredrik Correa explains how the new kBox 3 will improve the experience for our users, based on his background as a professional coach.
With the kBox 3 we wanted to improve the user experience by making it even smoother to shift between exercises and users. It was already one of the most, if not the most, versatile multi-exercise devices on the market but that was something we wanted to improve even more.
A new automatic strap adjustment mechanism means that the tower is gone and replaced by a small lever the you can press with your foot. When pressed you can either pull out the strap or let it go and it will then be retracted. When the length is adjusted you just let the lever go and you can start working out. You still have the superior strap length compared to other devices and only need the extension strap for overhead exercises.
With the new strap adjustment feature you can shift from leg to upper body exercises in a second creating completely new routines with super-sets, circuit training and other High Intensity Training routines.
In addition, this change reduces the height of the kBox when packed for travel by 26%, resulting in a beneficial improvement of flexibility for coaches and athletes who take advantage of the unique portability of the flywheel training device.
A second big improvement is that the surface area is increased by 12.5%, without being larger in the base. In addition to the removal of the former strap adjustment tower, this change results in even more versatility and flexibility in the training. You can move around, go deeper in the squat or sit on the kBox without interfering with the tower. This will be very welcome not only to our taller users but to anyone that want to use the multi-exercise functionality with the kBox.
The third important change involves the re-designed foot supports to facilitate single legs squats and to give heel support for two-leg squats and patella and achilles tendinosis. These are so new that we haven’t even had time to make proper photos of them to show you yet.
We hope to set a new standard with the kBox 3 when it comes to flywheel multi-exercise devices. Going forward, we believe that coaches and users won’t accept a limited depth or range of motion in the exercises or that you have to bend down to pick up a rope or turn a knob to adjust length.
Today, we start shipping the first kBox 3 directly from our new and larger production facility, to meet the increasing demand in both quality and quantity.
Our research and development section is never at rest, and we are eager to hear your thoughts on the design and functionality. Your feedback is what brought us here and we hope that you will help us to continue to improve. So if you have any thoughts, please contact us, or share them with us on Facebook or Twitter. Thanks in advance!
Eager clients have already pre-ordered the first week of production. If you are interested to get your hands (or feet) on the kBox 3, contact us or your local reseller today to request a demonstration or a trial. We are looking forward to hearing from you.
Fredrik Correa, M.D.
In a fresh article on the Freelap USA blog, olympic coach Carl Valle makes a great argument for the need to monitor performance during training and also to do this in a valid and accurate way.
When it comes to our kBox some people ask how to measure their work, which is a valid question. The answer is the SmartCoach system, which Carl also lists as a top 10 feedback system. The problem is that people I meet often want to relate the results “to my barbell squat in kg”. This is a different thing. My usual response is: “How can you compare if you don’t measure your barbell lift?”
Knowing the load on the barbells doesn’t tell your power output. It depends on the speed and the distance the load travels, and you have to measure this as well to compare. I hope more coaches and athletes pick up this from Carl and start to look at their training in a more sophisticated way, using all the benfits that new technology offers.
I’m also glad to read Carls fine remarks about the kBox, which in his words delivers “an unholy amount of force to the lower body” and that the kBox is the future closed-chain replacement of the Nordic Hamstring Curl. We think so too.
/Fredrik Correa, M.D.
Force comparison between barbell and kBox flywheel squat using force plates and SmartCoach.
Swimmers that do lunge exercises on a flywheel squat device such as the Exxentric kBox prior to a race get a 35% faster start. This is evident from a new study from the University of Granada, which validates the so-called post-activation potentiation (PAP) protocol.
Numerous studies have shown that using a flywheel device results in higher muscular activation and muscular forces during training. As a result, increases in strength and hypertrophy are higher during a flywheel training regimen as compared to using traditional weights.
Can this higher activation be useful in a race context too? The answer is Yes! Post-Activation Potentation (PAP) is a technique to elicit higher muscular force in explosive actions. This has been explained well in an excellent article by sports scientist Bret Contreras:
“The underlying principle surrounding PAP is that heavy loading prior to explosive activity induces a high degree of central nervous system stimulation which results in greater motor unit recruitment lasting anywhere from five to thirty minutes.”
PAP has showed mixed results in studies and the conclusion has been that the protocol (type of exercise, intensity and rest) before performance must be validated. It is therefore interesting to read a new publication from researchers at the University of Granada, who studied two different protocols for PAP before swim start. They compared them first to each other and then to warm-up only. PAP consisted of either three reps of barbell lunges (85% of 1 RM) or four lunges on a first-generation multi-exercise flywheel device.
Results showed that mean horizontal velocity in the swim start increased by 35% with the flywheel lunges as compared to warm-up only and by 18% as compared to PAP with barbell lunges. This flying start gave the swimmers faster times to 5 and 15 meters after the flywheel PAP and this protocol can give the swimmers a significant advantage in shorter events.
/Fredrik Correa, M.D.
To learn more about how your team could use the Exxentric kBox to benefit from these results, please contact us today.
This quote about the Exxentric kBox comes from US based track coach Chris Korfist, who has produced 59 all-state track athletes in the last 22 years. We read his statement in a new article on Just Fly Sports about his work as a sprint coach. We wanted to learn more, so Exxentric co-founder M.D. Fredrik Correa contacted Chris to ask some questions. He was happy to share his views on successful sprint coaching and the benefits of using a kBox.
Fredrik: In the interview on Just Fly Sports you said that the kBox is “the best piece of equipment that I have come across”. Can you elaborate on that?
Chris: Most equipment on the market is just dead weight. In some cases, it is even less when you add pulleys and other devices that lessens the pull on the muscle. The kBox is more like sport. In most athletic movements, an athlete is required to respond to the force imposed on their body. For example, when running, an athlete has to absorb the force driving the body into the ground by springing back into it. In most cases, that amount is more than two times the body weight. On a regular piece of exercise equipment an athlete won’t experience that force, but he will on a kBox. An athlete has to stop that wheel and reverse it. Put a couple of discs on and an athlete will feel that force.
How do you use the kBox in developing faster sprinters? What exercises do you do?
As I mentioned, we try to get high forces into the athlete and try to replicate that same motion as running or jumping. To do so, we do single leg squats, split squats and regular squats using a variety of belts so an athlete can pull from different body parts. Some people recruit differently based on where the pull is originating, so I designed some other belts to have athletes drive from the muscles that I want to develop. The harness is great but some athletes feel too much back so I have rigged a belt that I can pull from different areas to get the individual to work what I want. We also wave load the different discs with the different exercises. We also do a hip hike for the glute medius muscle which works great with distance runners as well. And we do a psoas muscle knee drive that really gets a great glute/psoas combo. Romanian Deadlifts are great too for hamstring work. We will do RDL and then do a fly or single leg work and do an acceleration.
What advantages does the kBox offer that you can’t get with your traditional tools?
As I mentioned, the eccentric aspect is key to athletic development and the kBox offers the best in eccentric training. The flywheel mechanism is a great way to train reversal strength. You can see someone’s power by watching the wheel change directions.
After using the kBox for some time now, what effect do you see in your athletes?
I use laser timer and jump pad to constantly measure my athletes and I saw bigger gains this summer than I have in the past. I had a larger group of athletes jumping over 32 inches off a mat. And these are high school athletes. We saw similar improvements in block 30’s and fly 10’s as well. I also use a muscle lab to measure output in single leg exercises and have seen an uncommon jump in power output as well.
Sprint speed is crucial in many team sports. What are your basic tips for coaches in other sports when it comes to speed training?
Don’t put too many spices in the cake. Focus on one aspect of an athlete’s development. Bigger, faster, stronger is a myth. And rest is a workout. Let the body fully recover before going at it again. Most people never see what happens as a result of a workout because they get slammed with another one.
What advantages do you see with being able to do the training in the field?
The biggest advantage is to be able to do an exercise on the kBox and then go sprint or start or accelerate or jump. Appropriate rest is needed in between the two. The kBox does cause quite a bit of fatigue.
Do your athletes feel any difference between squats with high or low inertia on the kBox compared to free weights and if so, what do they feel is different?
The kBox feels alive. It is trying to pull you into the ground. A barbell just feels like dead weight. 2-3 plates on the kBox is a great eccentric workout.
That wraps it up guys. Hope you enjoyed the reading! /Fredrik
About Chris Korfist
Chris has been coaching track for 22 years in Illinois, US. He has coached high school athletes at Hinsdale Central, Downers Grove North and York HS, producing 59 all-state track athletes, three individual state champions, two team state champions, three 2nd place team finishes, and two 3rd place finishes. He owns the Slow Guy Speed School which is a gym that focuses on running and athletic development from which other all-state athletes have trained. He used to run the Inno-sport.net and Wannagetfast.com web sites with athlete coach Dan Fichter. He also had the opportunity to work occasionally with some Olympic sprinters and other professional athletes.