Body by… Inertia? Application and Physiology of Inertial Training on Performance and Physique

My first experience with flywheel training was with the Versapulley some 15 years ago. The novelty of what is also called rotary inertia resistance training, quickly became a love affair on which I have nearly staked my professional life.

While at first I thought I was simply replicating power cleans in functional planes of motion, it became clearer to me that I may have found the optimal replacement for repetitive Olympic weightlifting for metabolic conditioning.

Simply bringing the device to the UK for a demo, turned into a 5 year stint with a pro rugby team where I championed the use of flywheel training for return to play programming. When running fitness and physical contact was not possible or desired,  I created a structural and metabolic bridge back to on field play with high intensity interval flywheel training.

With an inquisitive look from physios and fellow fitness staffers alike, this Californian who had never before seen a professional game of rugby was using the coupled maximum concentric voluntary contractions and proportional eccentric overloading, inherent with inertial flywheel training, to accelerate players back into the game.  I was sure the self propelled and decelerated spinning cone- the Versapulley- was a game changer for sports performance and  emerging CrossFit sub-cultures alike.

About the time CrossFit was just starting, my exposure to the world of High Intensity Interval Training for professional Rugby was taking place. Working for London Wasps in the Craig White era when Power Endurance became its own colloquial term within the sport, I was forced to address the need for repeated power ability.

Better understanding the needs analysis and practiced methods in European Rugby and Soccer, while keeping an eye on the CrossFit® trend eminating across the globe, I quickly identified flywheel resistance as a great solution when training world class rugby players returning from injury.

The ability to repeat ‘heavy’* loads with minimal joint stress and momentum shift, allowed me to work athletes deeper into their anaerobic energy system without the risk of shoulder, wrist, back knee overload. 

Yet in the process of reverse engineering neo-classical metabolic conditioning, I had maybe lost sight of some of the original applications of flywheel training.

Prior to my London days I formulated my early sports science view via a group of Spaniards and Italians who were doing heady research and application with the flywheel. In Barcelona, Dr. Julio Tous opened my eyes to the broader applications to inertial resistance and the research of Per Tesch and Marco Pozzo. It was through their research on long term space flight and soccer players that I originally understood the technologies place in the world of training strength and muscle mass. Yet, when one gets bent on supporting an idea to be the innovator or monetizer, the basics often get lost in the ‘spin’.

So It was when I got out of my rugby sub-culture, that I began to return to these original purposes of flywheel application: basic size and strength.  Part of this was the fact I was using the Versapulley, which allowed for free range of motion and a quicker movement patterning, enabling more functional work but less concentrated eccentric force, but more so, it was the broadening of my training clientele that brought me back to the deeper impact of the type of resistance.

It was in dealing more with a growing diversity of adult populations and ‘asthetic based training, that I started looking again at the basic tenants of gaining lean muscle mass for looks and function.

I had been dealing either exclusively with professionals who were already at an optimal playing mass, or young athletes whom there was a premium on dealing with movement patterns, where the Versapulley fit perfectly. Yet, in opening my own training facility for off season work I was learning that I needed a few adult clientele who simply wanted to gain lean muscle mass and look good for summer. Reluctant to even buy a dumbbell set or allow bodybuilding for my young and “aging athletes alike”, I stuck to my sports performance guns to build higher functioning human beings.

I remembered my Poliquin education and meeting the man when I spoke at an Eleiko conference at his HQ in Rhode Island. We had a pre event dinner and when passing the salt I noticed just how big his arms were. In my post academic continuing education I remembered the Canadian’s passion for how important it was to train arm strength and probably passed it off as a misguided suggestion not for most sportsmen.

It is funny how that when we return to the basics, the complex issues are brought into a better light.

Bicep Curl Bias

As a football player at UC Davis in the late 90’s we had little direction for strength and conditioning. I actually am thankful for this because this struggle as a normal smaller guy to compete at decently high FCS level drove me to innovate in the weight room and on the track for not only myself, but for others on the team. I was wearing tights and cleaning the house before crossfit was invented and tights were popular outside the track and field culture.

paul cater 2

Though I had no clue what I was doing, it was great because I wasn’t confined to a program or a static theory that was the social media flavor of the day.

For all the innovative things I thought up, I remember a few mistakes.

  • Carbo loading the morning of a big game
  • Going cold turkey on squats for a year
  • Training a little too much bicep brachialis prior to game day

Going nuts on bicep work before walk through day on Friday- though good for jersey tightness- probably caused a few missed tackles on Saturday. The joy of wearing just jerseys and our football pants led myself and few guys to hit the guns for game day prep. I wouldn’t say this is necessarily a bad thing, but I can remember being a bit fatigued on gameday and missing a few tackles wishing I didn’t have a massive arm day some 18 hours beforehand. 

That experience, as well as my delve into academia to become a strength and conditioning coach ironically in subsequent years led me away from working bicep curls and arm days in general. As I began to Oly lift more and crank on pullups I didn’t see the need. Yet, 15 years later I decided to work my biceps on the Kbox flywheel training device and voila, a perspective shift.

Open Mind

I was working for Baltimore Orioles at spring training in 2014 when a renowned slugger inspired me to do bicep curls again. This time it was a different flywheel device, the Kbox®, a derivative off the original YoYo® flywheel device.

Working on the same principles of cyclical stored and released energy exerted and managed by internal force production- and in this case a cylinder rather than a cone allowing for higher linear loading properties- the bicep curl and squat are enabled.

A heavier response from cylinder and strap- not having to work through pulleys (which allow for more functional sport motion) can induce a little more damage (in a good way) in the muscle’s lengthened state when the brakes are put on for the subsequent concentric part of the repetition.

All that being said, over the course of 6 weeks I gained nearly 2 inches on my arms. To infer what high speed eccentric loading can accomplish for baseball activity I must right about another time, but it in my simple experience it only helped with my bicep tendinitis and shoulder pathologies resultant from throwing a baseball everyday with less than perfect form.

A photo posted by Paul C Cater (@coach_cater) on

So it was when  I was back into the restful world of American sports that it finally clicked what was truly functional hypertrophy- gaining bigger muscle cross-sectional size that actually does stuff at high speeds in functional ranges. If a guy can do curls pre game and lead the league in home runs, I thought I could add in an arm day here and there– I didn’t expect to get to 18 inch arms in 6 weeks over that Spring Training, and still be able to throw a baseball (albeit my form is still under intense scrutiny from the pitching staff and players alike).

Blurring The Cultural Lines

In my opinion, the sports performance sub culture has reacted against any compartmentalized method and form of training. What is usually popularized for public consumption usually doesn’t work for optimal athletic development and sport performance. This at least was my experience.

Gaining muscle size is the usual driving force for young males in high school; in my case I had a hard time understanding how body building and training for sport performance weren’t always the same thing. Further to wanting bigger muscles, strength is emphasized. The BFS program drew me into powerlifting as a youngster and with it a wrecked lumbar spine. Whether it was the program or lack of supervision, I remember not being able to sit through history class and lying on the floor during 4th period, even though I was strong as an ox. As Crossfit may be replacing BFS and 1000 pound clubs,There may be different ramification as CrossFit permeates the high schools across America.

Self sustained cultures of specific exercise modes like barbell based metabolic conditioning, power-lifting, bodybuilding- even endurance racing like triathaloning demand almost cult following. Likewise, sport performance gurus can become just as hyper focused; over emphasis on one mode of movement- ladders and box jumps come to mind- drift away from a comprehensive and balanced athletic development model.

If the goal in athletic development is to develop health, performance and resiliency,  than surely coaches and trainers must present as broad a spectrum as possible within their means. Many times resources limit the comprehensive nature of programming, and more often its experience and adherence to what they have done or are currently participating in as an athlete. But good coaches will find the way to  implement all factors of athletic development, and use time constraint as a necessity of invention. Those with bigger budgets have even less excuses.

The point is that the training professional should seek to build bridges built between specialized training cultures and the social media streams and competitions which support them. Rare is there a comprehensive approach to implementing each mode of exercise- at least in the private sector where economics and marketing often drive the training method.

The Bridge

Along with an open mind, It is my belief that a couple devices help in the bridge building between specific modes of exercise and the sub-cultures that champion them. One of course is in fact the barbell. The other is the track or any surface to progress sprinting. Yet there are a few newer technologies that can bind together even these sub-cultures:  I believe the flywheel can have the effect of bringing professionals together to further all modes and models of training because of functional metabolic fitness as well as functional hypertrophy development.

The instance of eccentric overload at higher velocities creates a situation whereby functional hypertrophy can take place, allowing the good ol’ bicep curl – now almost taboo in sports performance culture- not only to make a glorious comeback, but be a bridge builder between the emerging training sub cultures.

Because I was always working in multi-joint, functional movement patterns bridging the gap for sport function and replacing Olympic lifting, big lean tissue growth can be accelerated via flywheeel training was almost hidden from me.

The body responds to high eccentric overloads with growth, maybe partly due to the hormonal climate of the eccentric lengthening and time under tension. The potential for bodybuilding was there for me, but not engaged with primarily because of its taboo nature, but mostly because it wasn’t needed as the professionals I was working with already were at or near optimal lean muscle mass for performance.

Rowers were great for conditioning but didn’t have the eccentric loading paradigm. Flywheel training achieved one of the most important tenents of conditioning in my mind- postural awareness and capacity to deliver force.

With high velocity eccentric loading, the user must achieve optimal trunk angle, shoulder position and soak up the energy via their legs every rep.

So as the players were dealing with higher loading of lactate because of the ability to work deeper into rep schemes without mechanical failure, the body awareness, hip depth and shoulder angle needed for contact and tackling improved. 

In the days before Rich Froning and the prototypical CrossFit physiques were mainstream on ESPN and at the cute girls at bars had massive traps, elite rugby players had muscle and could perform amazing feats of anaerobic endurance. The muscle was built to support metabolic function over 80-90 minutes.

As I was implementing flywheel for efficient muscle and energy system adaptation, I was forgetting a more basic benefit that could translate to a greater population: time under tension and greater relative eccentric loads for every rep can lead to resultant hypertrophy of muscle. And lots of people, even sportsmen and women need more lean muscle.

Eccentric training can do great things for your physique in terms of increased muscle fiber size. The trouble has always been the functionality of that muscle.

The cool part about using higher velocity eccentric loading that is proportional to the concentric contraction force is an inherent functional aspect to the muscle hypertrophy. The thought that one can body-build and hit mammoth home runs is intriguing.  At least a guy can tighten up the sleeves on the jersey for a pregame ritual, with less risk of having a negative effect on performance. 

Conclusion

I suppose we can lose sight of general application and principle when in the midst of establishing our own bias. Bias may be fed by attempting to establish a unique methodology through the guise of a team we work and can gloss over the basics.

In terms of flywheel training, I jumped straight to application for metabolic function without applying the simpler and maybe even taboo effect of bicep size. In the European sports theatre, strength of hamstrings keeps soccer stars on the pitch, and in NASA research astronauts from muscle wasting. It took me coming back to the USA to look again at maybe the original function of the flywheel: hypertrophy of muscle.

The irony is that it took the functional intersect of home run hitting to look at the eccentric benefit of the flywheel for muscle hypertrophy, without sacrificing function.

If we can look good and those looks can also help us play good, then beach workouts are not just a reward at the end of the week for doing all the other complex lifting.The greater implication may even be that traditional body building exercise, done under different tempos and stresses and forms of resistance may lead to higher function. In recent years with the Orioles, we have taught less low intensity functional movement- leaving the rotation for countless reps on field or in the cage- and more higher intensity simple compound lifting.  Squat, sprint and then go swing in the cage 200 times.

Maybe the ideal is squat and curl with flywheel, to gain a functional muscle mass that can handle high eccentric loads and move through entire ranges of motion, then go swing it.

The push for novelty can sometimes lead to missed applications. Coming back to basic body-building movements, but with with proportional eccentric overloads at higher contraction rates, can cover a multitude of training needs for a diverse training population. Yet, as I have noticed my own personal aversion to any distinctly marketed energy sub-system training ‘program’, my own bias has had a limiting effect on my own programming.


Paul-Cater PAUL CATER, MSc, CSCS, PCIP I, II

Founder of Alpha Project at Central Coast Athletics

Salinas High School, Varsity Baseball, Football 1995
UC Davis: Studied pre-law while playing UC Davis Varsity Football 2000
NSCA, Certified Strength & Conditioning Specialist 2001
Poliquin Certified Level, 2
Internships include UCLA, San Jose State, San Francisco 49ers
Graduate Degree Exercise Science, Human Performance, Brunel University, London 2010
MSC Strength & Conditioning from Middlesex University, London 2011
Over 15 years of experience as an International strength and conditioning coach working with London Wasps Premier Rugby, Baltimore Orioles, USA Rugby and consulting numerous other High School, College & Professional Athletes
Late Stage Rehab Specialist
USA ambassador for advanced training technology equipment including: Versapulley, Kbox and Smartcoach.

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