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Anyone have any comments on X-Rep training?

http://www.x-rep.com/index.htm

They ′supposedly′ took Arthur Jones′ principles and expanded on them.

… Did Arthur Jones know about the nervous system roadblock? Possibly. It may be why he often told people who were using low-volume, high-intensity training that to get the best results in size and strength, they must train to failure and then–and this is a key point–they should move the resistance as far as possible and hold it for an isometric contraction till failure. That hold at the sticking point had a lot of anabolic power, but most people using HIT never did it and rarely do it today. (Could that forgotten element be one of the big reasons HIT hasn′t lived up to its hype?)

That end-of-set contraction was supposed to be done on every exercise–or at least on the contracted-position movements–but somehow that important growth trigger has been forgotten, which is too bad because it′s a key to making shorter workouts much more effective.

We′ve taken Jones′ suggestion to the next level with X Reps. We′ve found that short pulsing actions at the end of a set are much better than static holds, as muscles are used to movement to prime optimal fiber activation. In other words, to keep the max number of fast-twitch fibers engaged, do short partials instead of an isometric contraction. …

source: http://www.x-rep.com/x_111304.htm

I did read the e-book. It′s basically this "go to failure, then do mid-range partials"

"Did Arthur Jones know about the nervous system roadblock? "

There isn′t one, that is a false beleif. I even emailed Steve Holman and showed him the studies, he said something like "Some research makes it look that way and it′s still a great way to train" He′s very nice so I just replied "OK, just wanted you to be aware of the current research, it does look interesting "

What′s funny is if the nervous system ′crapped out′ during a set, how the heck would partials work? If the fibers aren′t firing, they aint gonna fire period!

Az

Here is an awesome tidbit from the Enoka book, our CNS is NOT the culprit when we train to failure.

"Neuromechanics of Human Movement" 3rd edition, Roger M. Enoka

P. 374-375

Central Drive

The excitation provided by spraspinal centers is not impaired during high-force fatiguing contractions, but it can be during prolonged contractions. This limitation is expressed as an increase in the effor associated with the task, the appearance of tremor in the involved muscles, and the spread of activation to accessory muscles (Duchateau & Hainaut, 1993; Gandevia, 1998 )

The maximality of the activation provided by the nervous system to muscle is typically assessed through comparison of the force exerted during an MVC with the force that can be elicited artificially by electrical stimulation (Allen, McKenzie, & Gandevia, 1998 ) . This appreach involves applying single shocks or a brief train of shocks to the nerve during a fatiguing contraction. The test has been applied to both sustained and intermittent contractions performed at both maximal and submaximal intensities. For example, when subjects perfromred a sustained 60 second MVC with a thumb muscle (adductor pollicis) the force declined by 30% to 50%, but this decrease in voluntary force could not be supplemented by an electric shock (Bigland-Ritchie et al., 1982). Similarly, the maximal voluntary and electrically elicited force declined in parallel when subjects performed an intermittent (6-s contraction, 4-s rest) submxaimal contraction (target force was 50% of maximum) with the quadriceps femoris (Bigland-Ritch, Furbush, & Woods, 1986). In this expermiment, the maximum voluntary and electrically elicited forces were elicited periodically during the submaximal contracion. The parallel decline in the voluntary and evoked forces suggests that the central drive remained maximal during these tasks.

Later in the book he also speaks of long contraction times that do involve the CNS, BUT, after 30-60 minutes of rest, the CNS was able to put out full force once again, even though the muscles were still fatigued

To me, it′s obvious that chemical reactions will cause failure before electrical ones. That is almost always the case with everything in physics.

Darrell

I did read the e-book. It��s basically this "go to failure, then do mid-range partials"

Is this an effective way to train? I sometimes use partial reps when doing squats. I work out alone and can′t go to failure while doing squats, so I get close to failure and then do 3 or 4 partial reps to finish the set.