Are you attending the 20th ECSS Congress in Malmö? This Friday, there will be opportunities to get a private demonstration of the kBox 3 with the new kMeter feedback system by our co-founder Mårten Fredriksson.
The demonstrations will take place at a private location within close walking distance from the congress, and are of course free of charge and without any further obligations. If you are interested, please contact Mårten directly at firstname.lastname@example.org or +46706032912, or through our contact form.
Mårten is one of the co-founders of Exxentric. He has a B.Sc. in Sports Science and Physical Education from the Swedish School of Sports and Health Science in Stockholm (GIH), and 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 as strength & conditioning and tactical coach.
The kBox was built with safety and ease of use in mind, and there are only five simple rules that the user needs to bear in mind to start working with it. Here is Dr Fredrik Correa’s advice for a proper start with flywheel training.
The kBox is now being used in performance sports, health and fitness and rehabilitation with increasing popularity. Despite it’s small size and neat design, make no mistake: It’s a powerful tool that can give you the strength workout of your life, but it must also be handled correctly to not risk causing problems or even injury.
Fortunately no serious injuries have been reported, but as the kBox gets more and more popular and widespread, we have seen new users taking potential risks, that can be easily prevented. Here is a list of some common usage mistakes on the kBox, what can happen and how to minimise risk of any injury and damage to your device.
1. Falling backwards during squats
Getting a more accessible way of doing squats with higher loads, less dependent on form and ability to get eccentric overload were the main reasons for us to start develop the kBox from the beginning. kBox Squats is still probably one of the most common exercises performed with the kBox among everybody from elite athletes to patients or seniors in rehabilitation.
The thing is that when you try to decelerate the flywheel and reverse it to go up in the concentric phase the energy of the flywheel can shock you. In this position many tend to lose balance backwards the first time they push a little harder in the previous concentric phase and get the pull sensation in bottom of the eccentric phase. However, users rarely fall backwards and it just takes a couple of reps to get the hang of it, no worries, but it’s good to know so you don’t frighten your client with your new toy.
What you are doing wrong? You are unaccustomed to the eccentric pulling at the bottom of the squat.
What happens? You tend to lose balance backwards and might fall or get a feeling that you are about to fall.
How do you avoid that? Just by knowing there will be a hard pull you can be ready for this. Remember that the kBox is alive, it’s not a dead weight. Work with a partner or coach standing beside you ready to support you with a push in the lower back if you tend to lose balance. If you work without a partner you can put the kBox against a flat wall and let it catch you or just have it as a security measure in the first couple of sets. After a couple of reps you will get the hang of it.
Using a partner for safety: watch video.
2. Stopping in the top position or getting off when the flywheel is rotating
The kBox is alive. All the energy you put into the flywheel’s spinning motion will come back at you after you reach the top position. You decelerate the flywheel in the eccentric phase where at the bottom it is standing still for a second before you go up again in the concentric phase. This means that the stopping position is at the bottom where the flywheel has none or low rotational energy and this is where you should stop, not at the top where the energy is maximal.
What you are doing wrong? You extend all joints in the top position (in the squat for example) and stop or get off the kBox while the flywheel is still rotating.
What can happen? You can hyperextend you knee primarily and also get a high pressure on your knee joint. If you get off the kBox at the top, the spinning energy of the flywheel will retract the drive belt and since it’s not being held down by your bodyweight it will get off the ground and end up hanging in your harness.
How can you avoid that? Never stop in the top position, especially not in leg exercises using the harness. Use the snap shackle for a quick release if you need to unload yourself fast. For inexperienced users you can limit ROM so they can’t extend fully and diminish the risk of them hyperextending. When stopping, decelerate the flywheel in the eccentric phase until a complete stop at the bottom and then get off the kBox.
How to stop and get off: watch video.
3. Connecting the harness the wrong way
The harness is made so it will equalise the pressure on the shoulders and give a much more comfortable experience when training. If in an upright position the pressure will be over the shoulders/traps and if you are a bit leant forward the pressure will be over the lower back so you always have a short lever between the force and the lower back so there is always a minimal torque on the lower back.
What you are doing wrong? You are twisting the harness’ ends the wrong way when connecting.
What can happen? The edges of the harness will cut into your thighs. This can be unpleasant but not dangerous.
How can you avoid that? Connect the harness the right way by turning the harness’ ends inwards.
How to wear the harness: watch video. How to connect the harness: watch video.
4. Getting unnecessary wear on the drive belt
Basically the only wearing part of the kBox is the drive belt. To allow you to do a lot of movements in different planes and angles with a high force we gave you movement freedom, but with that came also a higher risk of wear to the belt. By minimizing the wear the kBox stays safer and you need to spend less time and money on changing the belt.
What you are doing wrong? You are letting the belt go against the edges of the kBox.
What can happen? It wears and you need to trim or change it.
How can you avoid that? By having the correct position you make less wear, make sure you are centered on the line between the shaft and where the belt comes out to the right. Remember that you are working in different planes at the same time, like the S-shape of the squat. If you are aligned perfectly in the top you will be positioned too much backwards at the bottom, so position yourself to get the best “average” position. You can also do a lot of exercises facing the short side, even squats. This way you get minimal wear. Exercises with a horisontal component can give friction belt-to-belt. To get rid of this, elevate the kBox in one end.
Position on the kBox doing squats: watch video. Changing position for smoother belt motion: watch video.
5. Giving up too early
The kBox3 is relentless and you can never beat it but that is no reason to quit early.
What you are doing wrong? You are quiting too early, missing out on the last reps on the set or skipping entire sets or just don’t squeeze out the last juice you got.
What can happen? Nothing really. Maybe you can miss some gains in strength and mass.
How can you avoid that? First of all, high-force-beastmode-all out-into-the-wall-training isn’t really necessary for getting the results you need. Sometimes you should give it all you got but for the most time, follow your plan, train, eat, sleep and let the results come. The kBox is very effective with it’s variable resistance and higher eccentric loads so you don’t have to do all that volume, all the time. Remember to pace yourself if you are doing multiple sets with higher rep range so you don’t overdo it in the beginning of the first sets. Use the kMeter to limit yourself because the kbox will pull you down and make you go harder and harder if you are not monitoring your load.
This being said, if you aren’t prepared to do a serious workout, don’t use the kBox. Have a Zumba or something.
See the kMeter in Action: watch video.
/Fredrik Correa, M.D., co-founder
Watch the full kBox introduction playlist here, it’s just about 10 minutes long (including the above mentioned videos):
Performance physiotherapist Adam Lovegrove is a long time user of the kBox in his rehabilitation work. Having ordered the kBox 3 and kMeter he published this review, which he gratiously agreed to let us share with you here.
For the last 12 months I have been using a kBox flywheel training device as part of my strength training programme.
I first came across flywheel training on a podcast by Dr Peter Malinares on tendinopathy rehabilitation. The way it works is you accelerate a flywheel(s) and then have to eccentrically work to decelerate it. The load encountered in each repetition is based on how hard you initiate the lift and accelerate the flywheel. This means that every repetition can be a maximum effort. This is especially the case if you perform a quarter squat with the upper body exercise to increase the acceleration which in turn increases the eccentric work required to decelerate the flywheel (believe me this makes it very intense).
The facts that each repetition can be a maximum effort and the eccentric loading is far greater than conventional weights means, in my opinion, it is a superior strength training method than free weights or machines. However having said that free weights are probably more effective if you are doing explosive, ballistic, weightlifting exercises.
In addition to using the kBox myself I also use it as a physiotherapist to rehabilitate late stage tendinopathies and as a maintenance tool to prevent recurrent injuries. This is very relevant to me as there are studies showing a link between eccentric hamstring strength and decreased injury or recurrence of injury (Askling et al 2003).
Exxentric have recently introduced their new kBox 3 and having watched the videos on You Tube I decided to upgrade my old kBox for the newer version.
The kBox 3 improvements
I have already written a review of the older version so here I will focus on the new innovations that Exxentric have added to the new machine and offer my opinion on them.
Firstly the length adjustor tower has been removed and replaced with an automatic adjustor that you can operate with your feet. This is simple to use and the main reason why I chose to upgrade. It means you can go from lower body to upper body in a superset format without delay and makes your training more time efficient.
The footprint of the machine is also slightly larger, although this did not affect me taller athletes with larger feet will benefit.
The machine also feels smoother when performing your lifts which in my opinion is quite an advantage.
Overall this machine is a considerable improvement on my original kBox and although expensive I think additional training strategies that can be applied and smoothness of movement make it a worthy investment.
The kMeter completes the kBox
Since initially writing this review I have now purchased the kMeter and accompanying app. The kMeter connects to the kBox and is linked to your iPhone or iPad via Bluetooth. You enter the number of flywheels being used so the inertia can be calculated. You then get immediate feedback of the force you are generating when performing your reps. The feedback also provides average concentric and eccentric power measured in watts and average force measured in newtons. You can save all the information for your training diary.
In my opinion this completes the kBox as training device. You can now receive instant feedback so you can monitor your progress, and evaluate your training status.
The fact that many health clubs appear to be incorporating areas for “alternative training” devices such as Bulgarian bags and Battle ropes. I am sure it is only a matter of time before the kBox becomes a feature in many health clubs.
Reference: Askling C, Carlson J, Thortensson A 2003 Hamstring Injury Recurrence in Elite Soccer Players after Preseason Strength Training with Eccentric Overload. Scandinavian Journal of Medicine and Science in Sports 13: 244-250
Adam Lovegrove has 20 years experience as a personal fitness trainer as well as 10 years experience as a physiotherapist. He has a Master’s degree in neuromuscular physiotherapy, specialising in movement control and rehabilitation as well as kinetic control movement therapy. He is currently studying for a second masters in strength and conditioning. Adam uses the kBox for both strength and rehabilitation purposes.
Learn more about using kBox for rehabilitation, or contact us.
A strong new review of the kBox 3 was posted by coach Drew Cooper on the highly regarded FreelapUSA blog yesterday. Exxentric co-founder, M.D. Fredrik Correa read it with interest.
People are purchasing the kBox 3 at an increasing rate all over the world, which is fun and stimulating. But being more a of creative idea-guy myself – a coach at heart and maybe not a businessman foremost – the greatest recognition for me is to get feedback from our users. End-users like gym-goers, patients or athletes, or coaches, performance directors, therapists or doctors, all have their personal opinion and experience with the kBox. We always want to take part of this experience to further improve our product and concept.
On this theme it was with great pleasure I read a review of the kBox3 yesterday, published on the FreelapUSA blog and written by Drew Cooper (CSCS, BS Kinesiology). Drew has been active in posting training videos from his sessions with different clients he works with in his three-car garage gym. Reading the review, I can really feel how the kBox suits Drews needs and how it improves the training for his customers. Like no other equipment the kBox offers heavy leg training and overload training in a safe, less technique dependent and more ergonomic way. All this packaged in a light product with a small footprint. I’ve have written about this before but in Drew’s story about the kBox it becomes so clear:
“It offers a unique way of training certain qualities such as high force with high-velocity eccentrics, larger times under tension with these specific muscle contraction regimes, improved speed of hypertrophy gains, and orthopedic safety—all with one piece of equipment with a small footprint.”
In terms of training physiology I like that Drew is talking about the fast eccentrics. Look up eccentric training on google and 9 out of 10 posts show really slow submaximal or assisted maximal reps, so far from performance you can come when in reality the eccentric work is often a fast deceleration in the stretch-shortening-cycle primarily like landing after a jump, change of direction and so on. If you look at the force-velocity curve and realise that the eccentric force produced is even higher at higher velocities you can understand that this is the way to work to really engage your neuromuscular system for improvement.
To sum up I wanted to highlight the essence of Drew post with a final quote:
“..the price isn’t cheap but the value is huge”.
We have never intended to do cheap stuff but our definite goal is to bring huge value to all our customers and users.
If you have other things to say to us, feel free to send your feedback to us via twitter or email. All feedback is helping us. Positive feedback keeps us going but the negative stuff makes us go in the right direction. Thanks in advance!
Go ahead and read Drew’s full review on FreelapUSA.com.
/Fredrik Correa, M.D., co-founder
As the launch approached for the kMeter feedback system, we invited the leading US based track coach and strength training innovator Chris Korfist to try it with his athletes. Here, he generously offered to share his thoughts with us.
One of the big jumps that I made as a track coach was my purchase of an electronic timer. After suffering through some lesser systems, I settled on a Summit timer and two Alge beams, wired. I now had instant feedback on how my athletes were running.
Giving athletes instant feedback on how well they do changes everything. From a psychological standpoint, it encourages flow in a workout. Thanks to Mihály Csíkszentmihályi’s work,* we know that instant feedback encourages individuals to improve faster. It also gives athletes the feedback to see if they are improving or not, which further encourages a positive training environment. And for coaches, it also helps to see if what you are doing is improving your athletes’ abilities.
What happens in the weight room?
The problem for a number of years was that while timers could help your athletes on the track, what happens in the weight room? Max weights are great but not always conducive for all phases of work in the weight room. If coaches are concerned with power output, we know we need to work at a much lighter range. I started with the MuscleLab and progressed to GymAware. Both great but we know that using barbells is not the best method of developing power in the weight room due to lack of eccentric activity.
Enter the kBox. Everyone who has tried the kBox will agree that after using it, traditional barbells feel like “dead weight”. The kBox feels alive. But the problem is how to quantify what you are doing on the kBox. That problem was solved with the new app that measures everything that happens on the kBox – the kMeter.
Visual response is immediate
The kMeter module that attaches under the kBox uses Bluetooth to connect to your iPad, IPhone or other iOS device. I use a HDMI cable to connect the iPhone to a TV so the display gets much larger. So, as the athletes are exercising they get immediate feedback which they don’t have to search for on a small screen. Visual response is much more immediate than a coach yelling out numbers.
I set the number of reps and weight. There is a 2 reps countdown to get the wheel moving and then the big beep, it is go time. As they exercise, a graph and number show their output. If you thought the kBox was difficult before, wait until you put a number on your effort. After your last rep, a new screen pops up and shows a whole range of info, which includes average power, which is displayed while exercising, concentric and eccentric peak power in Watts, average overload, energy, reps, rep time average, and estimated force in Newtons.
Explosive athletes ramp up power
So, I have been recording outputs for my athletes with the smaller flywheel (get better power output). While it is fun to have competitions between athletes, it is more interesting for me to make connections between what people can do in real life athletics and what they are putting out in exercise.
So, if an athlete generates x Watts on a kBox, he can also run x time in the 40 m or jump x inches in the vertical jump. My first observation is that my more explosive athletes tend to generate more power as the set progresses. So my sub 30 inch vertical usually hit their best number early in the set and sometimes completely collapse before the set has ended. Their top rep will be 3. The more explosive athletes continue to ramp the power, so their best reps are at the end. I am guessing what happens is that they can convert the eccentric energy into concentric better and continue to ramp up the output. They usually hit their peak by rep 6-7.
Also, the weaker guys can’t take that much eccentrically and collapse or slow down or lose their groove. So, someone who falls into this range may have a concentric average of 836w and eccentric average of 858w and an overall average of 620w. Their vertical jump is 24.4 inches. An athlete like this would benefit from eccentric work with weights, or an overload on the kBox, by helping him standup quickly (assisted) and getting him to absorb the force. On the other end of the spectrum, I have an athlete who puts out 1824w concentrically and 2194w eccentrically with an average of 1378w. He has a 37 inch vertical jump.
The concentric−eccentric relationship
I think the most interesting aspect of the kMeter that I have found is that even though someone’s power may not be that great, it is more about the relationship between the concentric and eccentric and this is something that correlates to athletic ability. For example, I have an accomplished high school distance runner who has a concentric peak at 710w but eccentric is 890w, 543w average and 23 inch vertical. While not as fast as a sprinter, he does very well at what he is trained for, distance running. The athletes who lack the eccentric strength are not “athletes”, meaning they are not smooth in movement.
I also use GymAware for my traditional weighted movements and have found that as athletes’ kMeter readings improve, so does their power outputs on the GymAware. I usually mix the two during a workout and add some movement that gets them off the ground. So, if we are doing single leg work, it would look like kBox single leg squat, GymAware single leg squat to single leg jump off a box.
Chicago Speed Clinic
As the weather has warmed up here in Chicago, I will get an opportunity to match kMeter reading with running times and try to make some more correlations between the two. If you want to visit Chicago this summer, we are hosting a Speed Clinic on June 19-20. For more information contact me at email@example.com.
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.
Today, we are happy to announce the first shipments of our new kMeter feedback system, for accurate monitoring of power and energy performed by kBox flywheel training users.
The kMeter system is developed to fit the fundamental feedback needs and budgets of professional flywheel coaches, physiotherapists and fitness facilities, as well as each individual athlete and user of the kBox.
We believe that the kMeter will change the face of flywheel training. It is an important milestone for Exxentric, where we move from only producing flywheel training equipment, to including also a new software based feedback system.
Training feedback is essential for many reasons. You need a feedback system to see where you are at. From that starting point you can set a goal and make your own program. During the training period the feedback can help you adjust your training. To evaluate your training you need feedback to see how far you have come. Feedback can also be used to limit an athlete or patient in rehab after injury or pacing before an event.
Many are lead to believe that they know what they are doing in the gym just because they know the number of kgs or lbs they put on the barbell but this knowledge is not sufficient. Kgs and number of sets and reps can be used mainly to quantify training volume but that really doesn’t say much about intensity – for that we need to know force and power during training.
The kMeter system
The kMeter system consists of two parts: The kMeter module is a bluetooth transmitter which connects to the existing sensor socket on most recent kBoxes. The kMeter app is developed for iOS devices and is available for coaches and physiotherapists as well as users.
Measuring force and power accurately is not trivial, and the kMeter system has been in development for several months. The development team has included individuals with decade-long experience of building flywheel training devices, as well a Ph.D. in Aerospace Engineering and a M.Sc. in Engineering Physics, accomplished in sports app development.
The kMeter system presents average power per rep, and also peak power in both concentric and eccentric phases to determine eccentric overload. The power data is exact and consistent. Number of reps, rep time and energy expenditure is also exact. Even qualified approximations of vertical motion (ROM) and force are presented. For a full presentation of the functionality, watch the video below.
An important aspect is the system’s backward compatibility. Existing kBox owners can connect the kMeter, as long as the kBox is equipped with a sensor.
As of today, the kMeter app is available to download for free on the App Store. The kMeter module is ready for delivery, priced competitively at EUR 390 plus shipping and taxes. Contact us or your local reseller to place your order.
We hope you’ll want to share your results using the “#kMeter” tag. We’re excited to see who will be able to show the highest power metrics on the kBox!
/Erik Lindberg, CEO
Some creativity goes a long way in creating specialised exercises on the kBox. Fredrik Correa reads a new article by sprint guru Chris Korfist, and sees implications for any strength coach.
Korfist is back at it again with another great article on the Freelap blog. A must-read for all you speed junkies. Besides that I really like his humble tone and way of storytelling. He is a huge resource of experience and knowledge in the field of sprinting.
Starting off with a discussion of the importance of being able to apply high amount of force to the ground to run fast, he moves on to five really great drills he uses. With explanations, pics and videos he tells us how they work and what they do. He also involves the kBox in several exercises which of course makes us extra happy. Having a guy like Korfist embracing our product is the best testimonial we can get and that really gives us a boost to keep going.
If you are considering to invest in a kBox and are looking at developing sprint power with your athletes you should really read this article. The knee lift drill to fire the psoas and the glutes and how he says he now can bring the sprint into the weight room is a great example how the kBox versatility can offer something new, something more than weights and rubber bands can. It’s alive. Another thing from the article is how he brings the kBox into the field and works sprints and strength together and how that makes their training more efficient and focused. Mobility here is key. He also makes a good point how the efficiency in training gives the athletes longer periods of rest and fewer sessions and how that translates into better results.
So, even if you are not a speed junkie or working with track and field or sprint athletes I think the way Korfist makes a synthesis of his knowledge and experience together with his creativity and the unique features of the kBox develops new ways to trigger the muscles in the patterns he want, at the speeds he want and with the intensity he wants can be insightful for others – how you can use the kBox as a versatile tool to create your own, specialised drills for your aims.
Read it and think about it, how can you improve your athletes with the kBox?
/Fredrik Correa, M.D., co-founder
Until now, flywheel training has been all about individual achievements. Tomorrow, this changes. As the first of it’s kind, a Swedish fitness chain will start offering a brand new group training concept using the kBox system.
Increasingly, flywheel training is gaining traction not only among sport performance coaches and rehabilitation physioterapists, but also in the larger health and fitness industry. Many of the benefits of flywheel training concepts in elite sports, such as variable and unlimited resistance and eccentric overload, are highly beneficial also for the general fitness client base.
Today, we are happy to announce a new co-operation in Sweden with one of Dalarna county’s largest fitness chains, Må Bättre. Starting this week, Må Bättre will introduce a new micro-group flywheel training concept including a personal trainer and up to five clients at their facility in Borlänge, run by successful entrepreneur and long-time kBox user, Peter Andersson.
This group concept is first of its kind in utilising flywheel technology and the kBox 3 to really grow muscle in a group training setting. As has been proven in several studies, flywheel training is supieror to traditional weight training in achieving hyperthropy to improve strength and muscle mass. Now the time has come for fitness clients to benefit from this too.
Beyond the training results, the mobility of the kBox – weighing only 15.7 kg and occupying just 0.5 m2 floor area – makes it ideal for facility owners offering various classes with limited space.
Full-Body Strength Program
For this brand new group concept, we have developed a tailored full-body strength program using the kBox alone, adding only a few body weight exercises. However, we expect that the personal trainers will extend and modify the program as their clients get used to flywheel training, and adapting to the specific needs of each group of clients.
Included in the concept is also the possibility to measure and analyse the actual power of clients and follow their development using the soon to be globally launched kMeter feedback system. We do believe that this will have profound effects on the clients’ motivation as well as the trainer’s possibility to give relevant advice.
With great power also comes great responsibility, and we want to ensure that the trainers are fully qualified to ensure safe and effecient flywheel training. We visited Må Bättre in Borlänge last week to give the trainer team a thorough introductinon course to the kBox (see photos). We discussed and tried different aspects of load, rest, eccentric overload, technique and exercises to be used in personal training and micro-group training. The trainers responded well and our course generated excitment and interest also among the centre’s clients.
Enjoying the Proven Flywheel Benefits
We are excited about this opportunity for fitness center trainers and their clients to learn professional flywheel training as well as enjoying the known and proven benefits of flywheel training for strength development in a group environment – and without the need for investing in a kBox system at home.
Training hard has never been easier.
Happy DOMS to everyone in Borlänge and beyond,
/Fredrik Correa, M.D., co-founder
Olympic track coach Carl Valle has published an interesting article on eccentric exercises and kBox training, which has already been shared widely. Fredrik Correa has read it with interest – here is his review.
When Carl Valle writes, I’m always excited to read it.
Carl is a US based coach who has produced champions in track & field, swimming and other sports, at every level from high school up to the Olympic level. This in combination with his expertise in performance data and understanding of practical applications of equipment makes him a great source of insight.
I found Carl’s new text a long but good read for anyone working with athletes or strength, both on eccentrics in general and on the kBox in particular. At the end he shares some of his interesting empirical results after a month of testing the kBox. More on that below!
Programming Eccentric Training
Even if you would not be interested in flywheel training for your eccentrics, I think the first general section gives a lot of valuable input about how to incorporate eccentrics in terms of restitution and programming.
Carl and I seem to agree that there is no reason to do “eccentric periods”, or even sessions, since this will give you unnecessary DOMS. Instead you should add eccentric reps in your existing programs, get accustomed to it, then increase the work with complete sets and maybe add some specific exercises like Nordics with a specific aim. Replacing your regular CON-ECC weight training with eccentric sessions in general will only take time away from training, with DOMS or fatigue or even break you down.
My tips for quality eccentrics; Start low, go specific, progress and then rest accordingly.
The kBox Results
We were happy to note that Carl Valle has given his kBox a thorough test ride. And the findings he shared of his month-long analysis were quite interesting:
“The results were very impressive, and the lean mass increase locally to the legs and hips were the fastest drug-free changes I have seen on paper. We hit personal bests in medicine ball throw output and maximal squat tests, but this is again empirical evidence.”
Fantastic feedback by any measure. Also, we look forward to hearing more from Carl as some effects remain to be explained fully:
“What is interesting is the EMG studies paired with the research on IGF-1, Free Testosterone: Cortisol ratio and Creatine Kinase markers. We did more work than usual. The ANS system was disturbed but we rebounded, and the hormones were not depressed but elevated. My guess is that inflammation may be higher than normal, but the gene activation was showing positive protein synthesis. I asked a few coaches and sport scientists, and the mystery was still present, so we will continue to experiment and track changes.”
Carl also shared a nice video of the kBox squat from his lab.
Choice of Flywheel Exercises
Regarding the choice of flywheel exercises, I want to add that there is much more to the kBox than just the kBox Squat or lower body work. However, it’s a great start and athletes with lower body focus might not go beyond this. I just want to point out this since PT clients, rehabilitation patients, gym-goers or crossfitters can benefit a lot from the upper body drills too, so don’t forget them.
And the kBox is not only about heavy eccentrics either. You can do high volume training or explosive training, just take a look at the force-velocity curve, adjust speed and inertia to match your aims and go.
Thanks for sharing your thoughts Carl, we look forward to hearing from you again.
/Fredrik Correa, M.D., co-founder
PS. See also my previous post discussing another article by Carl, about power measurement.
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