Tuesday, March 25, 2008

The Disappearance of the Posterior Chain

It wasn't too long ago that all the talk in the strength and conditioning world was about developing the posterior chain.

"Front for show, back for go."

Missing

Nowadays, true posterior chain strength work seems to be disappearing? It seems that many strength coaches are abandoning some great posterior chain exercises in favor of rehabilitation type exercises. Glute bridging, single-leg glute gridges (Cook Hip Lift), slideboard leg curls, quadruped hip extension exercises, and single-leg RDL's seem to be the flavor these days.

My question is what happened with bilateral RDL's/stiff-leg deadlifts, deadlifts, glute-ham raises, cleans and snatches from the floor, or even straight-leg hip extensions (remember the "old school" roman chairs)? Did these exercises become obsolete? Were the coaches who used these exercises with great success, for years upon years, wrong when it came to working the posterior chain?

The key is critically looking at any exercise in both a biomechanical and physiological sense. Questions that need to be answered: does the exercise recruit high-threshold motor units and does the movement put the specific muscles in an optimal mechanical position to function? Not many sports, especially team sports, involve low-threshold motor units (slow-twitch fibers) and limited hip flexion and extension. What is the adaptation from low load, low velocity exercises and their carryover to high load, high velocity activities? (principle of specificity)

For example, does a glute-bridge (any version; single-leg or double leg) or slideboard leg-curl recruit most or all of the possible motor units? Do these exercises take the hip through a full range of motion to get maximal activity out of the hip extensors? My answer would be, no they do not. Could they be loaded to increase motor unit recruitment... maybe, but I haven't found a very effective way to do so, and again you can't or don't get a pre-stretch of the hip extensors into hip flexion.

How about a standard 2-leg RDL or the glute-ham raise? Do they or can they recruit high-threshold motor units? Most definitely. When done correctly do they biomechanically stretch and contract the hip extensors? The glute-ham raise, depending on how it is done, may or may not, but it certainly gets work out of the hamstrings, and the RDL absolutely does.

Also one of the main functions of the glute complex is to control forward lean of the torso, some of the above exercises negate this very important function.

Now I must be clear on everything here, I most definitely have and/or do use some of the previously mentioned exercises. Some of the glute bridging and other exercises can be great for pedagogical purposes. And I am aware that a single-leg RDL can be loaded relatively heavy and of the research behind bilateral deficit, but the load on the system in any bilateral exercise, I would argue, does quite a bit for the development of the athlete.

Single-leg training is important for balance of musculature, reducing the bilateral deficit, and recruiting stabilizing muscles. I do think single-leg/limb training is a necessity, however...

... areas of question that I have: the stability component of high speed movement is much different than weightroom stability. Running actions are cyclical and the effect is more like a gyroscope with the actions of the arms and legs; the need for single-leg stability is minimal. Multi-directional movement is different and does require a tremendous amount of single-leg stability, but the force vectors required in multi-directional movements require more horizontal stability than the force application and vectors in the weightroom which are more vertical in nature. Also, upper body mechanics play a larger role in lower body stability during dynamic movements than one might think...

The key is to train and strengthen posterior chain/hip complex, not just stimulate it.

Front Squat vs. Back Squat

There has also been an increased favor towards the front squat as opposed to the back squats when it comes to knee dominant exercises or lower body pushing, if you will. The thought is that the back squat places too great of a load on the low back and that the front squat reduces this load. Research shows a slight difference, and looking at moment arm lengths when watching a squat this can be visually seen to be true with the increased forward lean and hip flexion in the back squat as opposed to the front squat. But this increased hip flexion leads to increased activity out of the hip extensors which in a anterior/quad dominated society can be a very good thing. So, could it be said... the back squat is a posterior chain exercise?

Plus, the increased hip flexion in a back squat lengthens the proximal hamstrings pulling on each muscles (semi-membranosus,-tendinosus, and biceps femoris) insertion at the tibia, which reduces the anterior sheer at the knee caused by the quadriceps (anterior displacement of the tibia on the femur). (Also why hip flexion upon landing is so important for females... the increased "tug" from the hamstrings reduces ACL stress)

Another positive of the back squat is the necessity of increased dorsiflexion at the ankle. This stretches the soleus/gastrocnemius complex creating an extension moment at the knee, again reducing and/or neutralizing anterior sheer on the knee.

Another overlooked aspect when it comes to the front squat vs. back squat is the necessity of thoracic extension to maintain good technique. Yes, I am aware, that those with shit for posture (myself included) can make up for this with abduction and increased external rotation at the glenohumeral joint, but with good coaching this can be worked on and improved. The front squat does require upper back extension but is limited with the reduction of an anterior sheer force and abduction of the scapula.

These qualities to the back squat and a whole lot more...

There are many more benefits to the back squat than the few I listed here and I think it is safe to say that the back squat IS an effective exercise. I believe both the front and back squat have a place in a program, but I don't believe that because "so and so" only uses the front squat, that the back squat needs to be banished for eternity.

In a program lacking high load, hip flexion to extension posterior chain/hip dominant work and utilizing only front squats, there is a missing gap. Single-leg exercises may help, but most are anterior/knee dominated movements. An anterior dominant program is great for acceleration out of blocks or a three-point stance in running the 40 yard dash, but limited in "upright" acceleration (which most sports involve) and top-end sprinting and most importantly in injury prevention.

To wrap things up...

-The posterior chain needs to be trained in a way that induces high threshold motor unit recruitment and effectively targets hip extension from a pre-stretched position of hip flexion.

-Back squats are a great exercise.

AS

Thursday, March 13, 2008

Good reads

Vern Gambetta had two excellent posts today on his blog about the thought that athletes need to build an "aerobic base".

"Building an Aerobic Base"

"More on Aerobic Base"

This was a response by Jack Blatherwick addressing his views on the topic. Jack makes some excellent comments about the neuromuscular repercussions of steady-state aerobic work.

AS

Tuesday, March 4, 2008

CNS Intensive Training

Most training should be CNS intensive; speed of, strength of, power of, quality of, even conditioning and recovery work affects the CNS, just at a lesser percentage of 100% effort, which is unattainable anyway. You can’t separate the nervous system from the rest of the body. (The S.A.I.D. principle rules all)

The latest reaction to this whole CNS “craze” is blown way out of proportion. Much of it is in response to Mike Boyle’s programming changes he made this past summer with his the Boston University men’s hockey team and the conferences in which he presented on it. Now don’t get me wrong, I loved his presentations (I saw him present on it in Atlanta, which was the same presentation I saw a couple months earlier on the DVD of his talk he did at his own winter seminar at his facility), I like his line of thinking on things, and the fact that he isn’t afraid to make changes. The problem is he presented on his situation, repeat: HIS situation, with elite level college hockey players. People take this as the bible and think it relates directly to them. Sorry folks not many are working with those types of athletes.

Boyle works with higher-end athletes with his BU hockey team, and it was only really affecting his 3rd and 4th year guys. Their numbers were basically “stalling out” after 2 years with the program. Guys that have been in the program already for 2-3 years, plus knowing hockey, many of these guys are 22-23 years old (most play 1 or 2 years of juniors after high school). So you dabble a year or two extra of a little more serious training after high school, and then get to Boston University where Boyle puts them through the rigors for 2 more years and by year 3 they hit a wall. Add to it that they are college kids who live off pizza and beer and sleep only about 6 hours a night (I remember the days, I know, I have been there and done), so I would say their recovery isn't to great. Training is only as good as the ability of the body to recover. And recovery does take some effort.

So Coach Boyle makes their training a little less "CNS intensive". If I am one of his athletes I am thinking: "Hell yeah! We don't have to do as much, and we get basically two 'guns' days a week, and only one day of hard conditioning. Yeah I am going to work a little harder."

A player's psyche does make a difference.

Everybody hears about this CNS intensive training and begins to start treating the human body like some expensive piece of crystal. Yeah the body is precious, but it is lot more resilient than most people think. People have survived more dire situations than sprinting or stepping under a bar. I think CNS intensive, if there is such a thing, really only applies to those who are closer to their genetic potential, which nobody will ever ultimately achieve, but some get a hell of a lot closer than others. A young 16-18 year kid who is squatting a decent number around 350-400 and all his numbers follow accordingly, isn't really that close to his genetic potential, as much as some might like to think. And again, it depends on what each athlete is training for, is it strength, speed, power, conditioning? Where and what is the focus?

Our athletes at UND, train their asses off with what many people would call too "CNS intensive" training, but we still make gains year in, year out. If an athlete drops off at testing time, we look at many factors such as: did the athlete become sick at any time where-after training session numbers began to drop, does the athlete take care of themselves outside of training, do they eat well, sleep, outside stressors, injuries during the competitive season or off-season, etc.? Yeah the 3rd and 4th and 5th year (in the case of football) athletes don't make the gains that 1st and 2nd year players do, but they have been following similar programs since they stepped on campus. Program changes, in Boyle's case, go a long way, but most of it’s because the recovery factors haven't changed. It's not intensity, volume relationship; it's recovery - volume relationship that truly matters.

Good recovery, high volume.

Bad recovery, low volume.

Intensity always stays high (based on volume).

Obviously there are always exceptions to everything, but for the most part intensity should stay as high as the volume allows, following logical progressions.

Charlie Francis was one of the first guys (that I am aware of) that really brought to light the whole CNS fatigue thing, and we have to remember who he was working with. He was working with athletes who were near the peak of human potential and had been training with the guy for around 11 straight years, consistently. However, he didn't start worrying about the CNS control until all other factors were taken care of, nutrition, recovery (massage, EMS), hard training on the basics, and drugs (it has to be done at the Olympic level otherwise you wouldn’t be Olympic level). I don't think Charlie was too concerned with controlling Ben Johnson's CNS fatigue when he started working with him at 15 years old in 1977. Now did he monitor training stress, of course, but probably not to the extent that he did in the mid '80’s. Not until his athletes were hitting national and world marks did he really adjust his training to regulate CNS fatigue.

The majority of athletes aren't that close to world caliber marks.

But it would be ignorant for me to say that Charlie Francis was the first to ever to regulate CNS fatigue. Training stress has been regulated for years. You don’t think the ancient Greeks did some monitoring of their athletes? The Romans monitored the training of the Gladiators. What it all really comes down to is adjusting the training based on the level of the athlete and giving recovery focus. Training the human body has been around for a few years.

CNS regulation:
Training
Recovery

AS

Saturday, March 1, 2008

Beijing '08 (Chinese Weightlifters)

Since I have been on the topic...

Here is some footage of the Chinese weightlifters training. Zhang Guozheng, the reigning Olympic champion in the 69kg class, is at shown in the beginning of the footage in the black shorts and no shirt. Midway through is another 2004 Olympic champion, Shi Zhiyong.

Communism sure helps these countries in sports such as weightlifting, just as it did for the East Germans and Russians back in the day.

AS