Unilateral Maximal Eccentric Loads/Overloads

Much respect to you, Dr. Darden! I learned about the 30-10-30 technique when I bought your Killing Fat book for Men’s Health. Since then, I have always been mindful about training the negative.

I just learned about an exercise device that allows for unilateral maximal eccentric loads/overloads. It can be done anywhere and without spotters. It uses a 4:1 mechanical advantage pulley system like rock climbers. So while one arm exerts 100 pounds of force, the other arm controls it with 25 pounds.

I am not affiliated with the company. Rather, I just purchased the device and await delivery.

But I was wondering if Dr. Darden had seen it or used it and what your impressions of it are? From the looks, you can maximize your concentric and eccentric loads thereby burning all your muscle fibers for total exhaustion. It seems like a game changer but I’d never heard of it until last week.

It’s called Synapse CCR. Many thanks for any insight.

Several of the new digital machines with motorized resistance allow for true overload on the eccentric. I’ve often wondered what Dr Darden would think of those.

I haven’t used one but I am curious how you like the Synapse.

It seems like it would take some effort to coordinate the resistance but once you get past the learning curve, it could be valuable.

Well the unit came in today! Here are my initial impressions after toying with it.

  1. Form factor is quite small. It says it is rated to 660 pounds, which is more than enough for unilateral work.
  2. I clipped on some hard handle grips to both ends. The OEM grip on the working side is semi-rigid plastic tubing. The other side is a fabric loop.
  3. With a 4:1 advantage, the guiding arm moves four feet for every foot the working arm moves. There are a couple of consequences to this:
    A. It’s very hard to do a one second negative and maintain a tight rope and max effort throughout, especially on longer movements. Looks like a 2.5 to three second negative is the functional limit on cadence. I will probably be using a 6 up/3 down cadence.
    B. On longer moves, it is better to position your body slightly “Open” to the non-working side to give yourself maximum distance in the non-working arm. If I am doing a row with my left arm, my right foot, hip and shoulder are slightly back. I don’t know how this affects the biomechanics.
  4. The Synapse requires more effort when the body is leaning away from the anchor. Like a suspension trainer. The leverage gives you some starting tension to work with both on the positive and negative. Thinking long term, aside from more sets/reps, I am not sure how you progressively overload body lean. Perhaps a weighted vest? Or gravity (find a hill)?
  5. You can also create starting tension by hooking the Synapse to a resistance band and hooking the resistance band to a door anchor. If you lean away from the door anchor with some pretension in the band, this works too. Progressive overload is easier to manage - just use stronger bands over time. However, as your arm moves up and back, half of that move is coming through the Synapse and half is the band stretching and contracting. I’m not sure how that affects the negative force as bands usually generate less force as they contract.

Interested to start this journey…

First Synapse workout this morning. Pec flys & reverse flys at hip door anchor level and triceps overhead extension from a bottom door anchor.

I am using it solo. Synapse is very easy to use with a partner or trainer. You just push or pull the handle as hard as you can and the partner manipulates the guide rope. No adjustments in form are necessary. In addition, your brain doesn’t know how far or fast the the guide rope will be moved, so you can focus on the move at hand.

Using it solo requires some body movement in order to get a full range of motion. Instead of articulating the joint around the body, at times you need to articulate the body around the joint. You are focusing on a couple of things besides the effort of the working arm.

Finally, I am trying it two ways: as designed and with a band. As designed, the guide rope always moves at a 4:1 pace to the working arm. With a band, moving the guide rope may not move the working arm. Rather it might stretch the band. This can be useful as stretching the band at the end of the positive overloads the negative. The band wanting to contract eventually overcomes your muscle. Also, pretension in the band makes the banded move feel “heavier” to me throughout.

I would like to thank @CougarRed (again) for sharing his experience and knowledge about the Synapse CCR - which eventually made me research the equipment and buying it! As things turned out - I happen to love the Synapse. The inroad is significant and represents a new feel compared to traditional equipment. And yes, I get annihilated by it sometimes, as the recommended set continue for 90 secs. Obviously, it’s just another tool in the trainee’s toolbox - but it does offer something different. Bear in mind though, you have to like slower reps to enjoy it. And yes - it is a pulley system of sorts.

I believe the Synapse may be of interest to any trainee looking for a portable system, that can produce significant force without risk, accentuate the negative and provide quality time under tension.

Much to my surprise it actually works! There is a learning curve though, to become comfortable and getting the most out of the movements/excercises. Working unilaterally only makes you focus harder on the muscle under load. Also, you often maintain a “half lunge” stance in order to be able to prolong the rep - to reach full contraction/extension. Over the course of a workout, the legs get murdered.

The rep tempo is best kept over 2-3 seconds on both positive and negative, to be able to apply enough force - though you probably can experiment up to about 10 secs in either direction. I feel that 4-6 seconds in either direction is ideal.

Now, this device actually makes it possible for me to train time efficiently - full body in 30 mins - making the training happen - which is what it’s all about. Also, its great with something new that keeps you motivated. As much as I love the gym, this is actually a good 2nd best alternative. Maybe a bit expensive on first impression, but if it lasts long enough, and you can spare the $ - it may be worth it.

I would be very interested to hear what Dr Darden @Ellington_Darden thinks about it - or if anyone else have tried it? Please share your experience.

@CougarRed : Can you please expand a bit on the use of resistance bands with the Synapse? Do you fit them to the anchor?

To any mods - This is NOT intended to be a sales pitch of any kind. More my personal review of the Synapse. Not for everyone. If you think this is borderline sales - feel free to remove it. After all, the gym is always the best option, in my opinion. This is just another way of training.


Glad you like it Pettersson!

What convinced me to keep it after the 30-day trial was how: 1) The negative measured 20-25% heavier than the positive on my scale, and 2) The Synapse thoroughly exhausted me as the 90 second mark approached. Take shoulder press. By the end, I barely applied any resistance and it was a struggle to complete the movement. To me, this confirmed the owner’s claims of the accentuated negative burning through all available Type 2 fibers and getting the Type 1s in hypoxia.

The owner doesn’t use bands, but sometimes I use the Synapse with resistance bands for the sake of variety. I have two basic types of bands: layered latex (Serious Steel etc.) and “fabric” bands (AnchorPoint Training). The difference is the APT fabric bands stretch to twice their length and then hit a stopping point whereas the layered latex continue to stretch. In both cases, I attach the band to a door anchor, and attach the Synapse to the band. So it looks like this: door anchor > large carabiner > band > large carabiner > Synapse.

With the APT bands, I take them to their limit and use the Synapse there. So the guide arm moves to keep the band taut while the working arm extends and contracts.

With layered latex from the starting position, the guide arm moves but what happens is that this stretches the band increasing the force on the working arm. The working harm holds the extended finished position as long as possible and then breaks down as the force from the band gets too high. I try to fight it, but the negative happens fairly quickly after the breakdown. Then positive movement against band tension as the guide arm comes back to the anchor. Rinse and repeat.

Note, I typically experience failure before 90 seconds using both band types.

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One advantage I can see is that there would be an infinite number of joint angles with this device.

I own a K-box which I really like, and enjoy the joint angle flexibility.

Thanks for the input @kcclone! I just proudly realized the K-box is a swedish invention (though flywheel training has been around for ages).

It looks like a great piece of equipment, and reviews are positive. Belt squats with a torso harness seems like the perfect excercise.

One question though: Can you perform slow negatives with it? Can you reach a 90 sec set with it? From the videos I have seen, everybody is doing explosive regular reps, for about 10 reps. Also, it seems you need to work up to a momentum?

That being said, I would love to try it. I have a CrossFit facility next door who has one! Maybe I’ll invite myself one day. I noticed you may also lease the equipment on a monthly basis. Good, considering it cost about $3K! I wonder if it’s 10 times better than the Synapse? Well, probably yet another great tool…

No you really can’t do slow reps. Long TUT movements would be tough to do in my opinion, but the upside is that It’s fairly constant tension and accommodating so unlike gravity based weights, it gives you *near peak force through all of the reps you perform.

Definitely worth checking out at CrossFit if they’ll let you.

Also, you can find Chinese knockoffs of the k-box for approximately $250 on Alibaba…. Not ideal I guess but it’s hard to pay 10x for something like that.

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Thanks for the review. The device is interesting, but it is at a price point above my “impulse buy” threshold. So it is helpful to read a positive review by someone that I know, and whose opinion I respect.

Do you know if there is a library or list of exercises that can be done with the device? Most of the videos that I see are upper body exercises. I’m curious about how it might be used for lower body work.

I’ve read about it. But have no experience using it.

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FYI - there is a 30 day free trial period. And you can spread the payments out over 12 months interest free with PayPal.

As for legs, I do lunges using the supplied belt. I bought some $15 Gymreaper ankle cuffs from Amazon and use those for seated knee extensions and lying hamstring curls. I believe the lunges and hamstring curls are demonstrated on the website.


Thanks, Al! I believe @CougarRed has answered your question. The leg curl excercise is excellent with a great feel - can be heavy indeed! Not forgetting the lunge, which also manage to create a great feel for some reason. Probably because of the low attachment point. Have yet to try the leg extension setup.

Your question is justified. If there is one thing I might have considerations about, it is the limit in terms of available excercises. But, on second thought, it works very well with the excercises at hand - and I’m not sure you absolutely need any more. Some excercises are slightly better than others in my opinion. As @CougarRed already have said (here on in the other Synapse thread?) the OHP is a killer! Excercises is an aspect in need of further investigation.

In addition, the sole thing that puts the synapse ahead of the competition is portability. It’s just a small bag weighing 200 grams. I brought it with me on a recent journey for easy setup in the hotel room. Say goodbye to imperfect hotel workouts.

BTW, I don’t use the supplied handle as it flexes slightly. I use a hard hollow plastic handle with rubber gripping. I thread it with 18" x 1" loop tie strap and connect the strap ends to a carbiner for my handle.

The OEM handle works well as a door anchor in a pinch, such as traveling.

My handle:
Screen Shot 2022-08-29 at 4.25.15 PM

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Great tweaks there!

Btw, have you invented any or discovered any new/other excercises for the synapse?

I saw on the Synapse FB page a clip of a standing bicep curl, that looked great. Am looking for a good tricep excercise, thinking how a pushdown or OH extension should be possible? Likely a problem on how to reach the proper length of movement.

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Personally, I use a bottom door anchor for both biceps and triceps. I face away from the door in both cases. For biceps, I lean away with the working arm “behind” me. It has the feeling of an incline curl. You can also use a top door anchor facing the door, which has the feel of a preacher curl. Try both and see. I prefer the incline.

For triceps, I perform an overhead extension facing away from the door with a bottom door anchor. However, you could also do a pushdown facing the door using a top door anchor. I prefer the overhead but YMMV.

For all the excercises solo, you have to move your body a bit (up and down or forward and back) for a complete range of motion. Working with a partner, there is no need for these adjustments.

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