Adarq.org

Interesting, but I feel like the muscles are getting more stimulated in the eccentric portion that the CNS... so...

Retarded broscience.

Eur J Appl Physiol. 2008 Feb;102(3):271-81. Epub 2007 Oct 10.
Resistance training using eccentric overload induces early adaptations in skeletal muscle size.

Norrbrand L, Fluckey JD, Pozzo M, Tesch PA.

Section for Muscle and Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, 171 77, Stockholm, Sweden.
Abstract

Fifteen healthy men performed a 5-week training program comprising four sets of seven unilateral, coupled concentric-eccentric knee extensions 2-3 times weekly. While eight men were assigned to training using a weight stack (WS) machine, seven men trained using a flywheel (FW) device, which inherently provides variable resistance and allows for eccentric overload. The design of these apparatuses ensured similar knee extensor muscle use and range of motion. Before and after training, maximal isometric force (MVC) was measured in tasks non-specific to the training modes. Volume of all individual quadriceps muscles was determined by magnetic resonance imaging. Performance across the 12 exercise sessions was measured using the inherent features of the devices. Whereas MVC increased (P < 0.05) at all angles measured in FW, such a change was less consistent in WS. There was a marked increase (P < 0.05) in task-specific performance (i.e., load lifted) in WS. Average work showed a non-significant 8.7% increase in FW. Quadriceps muscle volume increased (P < 0.025) in both groups after training. Although the more than twofold greater hypertrophy evident in FW (6.2%) was not statistically greater than that shown in WS (3.0%), all four individual quadriceps muscles of FW showed increased (P < 0.025) volume whereas in WS only m. rectus femoris was increased (P < 0.025). Collectively the results of this study suggest more robust muscular adaptations following flywheel than weight stack resistance exercise supporting the idea that eccentric overload offers a potent stimuli essential to optimize the benefits of resistance exercise.

J Orthop Sports Phys Ther. 2003 Oct;33(10):557-71.
Eccentric muscle contractions: their contribution to injury, prevention, rehabilitation, and sport.

LaStayo PC, Woolf JM, Lewek MD, Snyder-Mackler L, Reich T, Lindstedt SL.

Division of Physical Therapy, University of Utah, Salt Lake City, UT 84108, USA. paul.lastayo@health.utah.edu
Abstract

Muscles operate eccentrically to either dissipate energy for decelerating the body or to store elastic recoil energy in preparation for a shortening (concentric) contraction. The muscle forces produced during this lengthening behavior can be extremely high, despite the requisite low energetic cost. Traditionally, these high-force eccentric contractions have been associated with a muscle damage response. This clinical commentary explores the ability of the muscle-tendon system to adapt to progressively increasing eccentric muscle forces and the resultant structural and functional outcomes. Damage to the muscle-tendon is not an obligatory response. Rather, the muscle can hypertrophy and a change in the spring characteristics of muscle can enhance power; the tendon also adapts so as to tolerate higher tensions. Both basic and clinical findings are discussed. Specifically, we explore the nature of the structural changes and how these adaptations may help prevent musculoskeletal injury, improve sport performance, and overcome musculoskeletal impairments.

If you deadlift and then release the bar back on the floor at the top of the movement that's purely concentric.

There is some utility to that during peaking phases when you want to avoid microtrauma and increase IIX to IIA fiber ratio while still maintaining strength capacities.  I wrote about it in my "Fast twitch machine" articles. However, it's already built into a proper periodization cycle - a lower volume of overall strength work (or lower reps) will inherently reduce microtrauma even without specific focus on reducing eccentric exposure.

What the use of those methods will do is tax energy stores, which will significantly increase glycogen storage capacity, which will give you the illusion of significantly greater leg mass even if the things occuring at a cellular level aren't really occuriing.

Yah. There's a good reason the front squat is kept in the Bulgarian oly lifting programs. People have experimented with doing nothing but the competition lifts before. It doesn't work all that well. The competition lifts are a pretty strong strength stimulus and source of fatigue though.

Good feedback from everyone. Nice discussion.

A few things: Thibaudeau definitely isn't swearing solely by the concentric work. His prescriptions still consist of high sets of low reps on the bread and butter movents (Squat, front squat etc.), - something like ramping up for approx. 6-12 sets of 3 - 5 reps. He then recommends the rest of the workload coming from concentric only work, at a relatively high frequency. He even goes as far as saying that the more you do, the better.

My experience so far is:

- it does get you pumped nicely

- you don't feel fucked the next day

- some of these movements might sort out activation issues (glutes contract very hard on pull throughs) and iron out imbalances (dragging the sled backward or forward in a striding motion is unilateral by nature).

- I have a minor hamstring pull and this is allowing me to work the hamstrings without any pain.

I believe it's important not to overlook the fact that this is purely assistance work and is just one part of what should be a balanced program containing the basics.

From my experience, I find quicker recovery from eccentric less exercises, and I also don't think they need to be assistance based as thibideau says. Pushing/pulling a heavy object for a maximal effort for 10 seconds is not assistance, so I'm wondering in what context we're talking about for this type of training.

"These days, I'm using a weighted backpack from bounding/sprints and my recovery has shot through the roof. My desire workout has also increased. I do not feel adrenally drained, in fact I feel better, so I'm sticking with it for the next 4 weeks when I won't have a gym. I think Thibideau also pointed to studies showing reduced insulin sensitivity to the muscles

There is some utility to that during peaking phases when you want to avoid microtrauma and increase IIX to IIA fiber ratio while still maintaining strength capacities.  I wrote about it in my "Fast twitch machine" articles. However, it's already built into a proper periodization cycle - a lower volume of overall strength work (or lower reps) will inherently reduce microtrauma even without specific focus on reducing eccentric exposure.

What the use of those methods will do is tax energy stores, which will significantly increase glycogen storage capacity, which will give you the illusion of significantly greater leg mass even if the things occuring at a cellular level aren't really occuriing."

In response to Kellyb: first off, thanks for taking the time to help us young kids out. Secondly, say we push a heavy object for 10 seconds, how is that going to increase IIX - IIA? Just as with regular weight training, the load/intensity determines that conversion. If we are pushing at max effort with heavy resistance, we are recruiting IIX i would presume. I will read your fast twitch machine article though, i Probbaly have already however.

About the microtrauma, what if we kept volume similar? Would there really be as much microtrauma? And about the glycogen, I believe we are speaking of taking this to an endurance standpoint. If we take the eccentric-less ideas to apply to speed training, I do not see why the glycogen capacities of the muscles would increase as much.

Also, I think eccentric-less training is more natural and designed for our bodies, so perhaps better. Just a thought with no evidence, I wonder what everyone thinks.