DYNO Leg Press

Injured Reserve
A friend and erstwhile rowing companion recently launched himself down a ski slope a la Superman into some rock--kryptonite, I think. The contact substantially weakened his left shoulder and the subsequent metallic replacements should have him entertaining TSA folks for the rest of his life (no junk jokes, sorry). In the short term he can't row, or do much else for that matter. Lex Luthor, himself, could not have devised more heinous chingadera for my anonymous friend Robert, aka, Biff. This post is dedicated to his sanity.

"Anonymous" in better days: the only time we both occupied the bow together.

After recently posting on strength training; I was espied on a "strength training" device called a DYNO. One of my training buddies jestingly accused me of surreptitious strength training. What gives?

First, lest I give the wrong impression, I am not against strength training; I just haven't found any compelling reason to do it for rowing. I expect some day someone will emerge with some studies that suggest strength training actually improves rowing performance; until then I'll save my time and energy.

Secondly, I don't consider my use of the DYNO to be strength training; I generally perform a steady-state "leg press" workout for 45 to 75 minutes and use roughly the same stroke rate and force as I would in rowing. The leg press option on this machine feels very similar to the leg component in sculling. For that matter, it seems as close to actual rowing as you can get without using your arms (and shoulders!).  If this is strength training, then so is rowing on the ergometer or rowing itself. Me thinks I doth protest too much.

What is the DYNO?
Devised by the Marquis de Sade, this torture instrument has elicited confessions for all kinds of uncommitted sins. Produced for just a handful of years and sold by Concept II until 2007, the DYNO is a unique combination of variable resistance leg press, seated bench press, and seated bench pull. Short for dynamometer--a device that measures force--the DYNO is a push-me, pull-you looking device with two seats, various handles, and a monitor that flips to face either direction.

When you push or pull on the DYNO, the force you apply pulls a chain which accelerates a fan. Your force accelerates the mass of the fan and opposes the air drag of the spinning fan. The more force you apply, the more you accelerate the fan and the faster the fan spins. Simple, eh?

Not like free weights or traditional strength training equipment
While the DYNO exercises (bench press, leg press and bench pull) sound very much like the weight-lifting namesakes, there are some notable differences. On the DYNO, you can push or pull as forcefully as you want, as slowly as you want and as often as you want. Unlike traditional weight lifting, it is extremely difficult to "lift to failure"; you can apply minimal force and still perform a DYNO leg press, for example. Unlike most traditional free-weight lifting, there is virtually no resistance on the recovery (there is friction similar to that on a rowing ergometer). Unlike many weight machines, there is no "deadspot" where the resistance gets easier or more difficult; the resistance is a function of the force you apply. If you have a deadspot, so be it.

DYNO is similar to rowing in several regards
As in rowing, the resistance is directly proportional to the force you apply.
As in rowing, there is very little resistance during the "recovery."
As in rowing, you can change the "default load" by opening/closing the dampers, roughly analogous to changing the outboard on your oars (or inboard or ratio, etc)

DYNO Gearing
Like the rowing ergometer, the DYNO features dampers that control the air drag coefficient and what I call the "default load." For the same speed of movement, the more the dampers are open, the more difficult an effort will feel. Think of this as being analogous to a longer outboard (all else being equal). Similarly, if you close the dampers, for the same speed of movement, the easier an effort will feel. Think of this as being analogous to shortening the outboard on your oars. Clearly, the load is a function of the force the user applies, but just as the outboard on an oar affects the load in a boat so do the dampers affect the load on the DYNO.

When I use the DYNO, I close the dampers all the way; I want to be able to use this device for an extended period of time to simulate actual rowing.

DYNO Leg Press
I purchased a DYNO for our rowing club several years ago, specifically for people with shoulder, arm, and wrist injuries. You can see below that the leg press requires only the smallest effort by the hands and arms.

She has been sentenced to do this forever...

DYNO Research
"OK," your skeptic self says, "show me the research." Dr. Fritz Hagerman, Professor of Biomedical Science at Ohio University, conducted a couple of 10-week studies comparing the DYNO with some traditional strength training and the rowing ergometer.

In the first study, college-aged men and women were divided into three groups:
  1. DYNO-trained group
  2. Free-weight, sitting leg press group
  3. Non-training or control group 
The results showed that the DYNO group increased power-endurance more significantly than the free-weight and control groups. Additionally, the DYNO group showed a significantly higher increase in conversion of IIB(X) to IIA muscle fibers than the other two groups, suggesting "greater aerobic power."

In the second study, Ohio University Men's Rowing Club members all performed the same rowing ergometer workouts, but additionally:
  1. One-third of the participants performed DYNO Leg Press and Bench Pull training.
  2. Another third of the participants performed free-weight sitting Leg Press and free-weight prone Bench Pulls.
  3. The final third of the participants performed no additional training.

The results showed, most notably, that (quoting from the Concept2 site):
  • The rowing plus DYNO group improved power-endurance (aerobic muscular power based on repeated reps using free weights and DYNO).
  • The rowing plus DYNO group was the only group to significantly improve rowing efficiency and also the only group to show a significant correlation between isolated muscle testing results (DYNO and free-weight leg extension and arm pulls) and maximal and average ergometer score.
  • The rowing plus DYNO group was the only group to show significant improvement in anaerobic threshold. This is very important because the rowing plus DYNO subjects were able to perform an ever-increasing amount of work on the ergometer using the more efficient aerobic energy system to fuel muscle and thus reduce lactate production and the possibility of local muscle fatigue.
These studies were apparently not published in a peer-reviewed journal and many details are missing (I have asked) and the only place apparently one can find these results is on the Concept2 site.

The Hagerman studies suggest that the DYNO has some merit. Since we don't know the details of the studies, however, it is hard to know what merit badge to attach to this device. Did Hagerman have his rowers use short intense efforts or long sustained efforts. If I had to guess, I would say short efforts, thus contradicting my own DYNO use. Oh well.

Still, if you are slightly shoulder-impaired, and desperate for some rowing analog workout, you could do a lot worse than look to the DYNO leg press.

All DYNO photos used by permission of Concept 2.

1 comment:

T's Bees said...

This from Dr Fritz Hagerman in response to query before I wrote this post:

I have not published any of the results of these studies in scientific journals. We could probably submit the results to a refereed journal but the data is so specific to rowers; we also had very small N’s for each training group. Training regimens included performing 3X8 reps of the leg press to maximal effort 3 days per week for 20 weeks.10 male and 10 female university club rowers served as subjects. The same number and gender subjects performed the same training protocol using a standard incline leg press exercise. We also performed pre- and post- muscle biopsies on these subjects. The more task-specific Dyno results favored this group both for strength-power improvement as well as greater changes in muscle cell diameter and a more favorable result in specific fiber type changes. Thank you for your interest in our rowing studies. FCH