Showing posts with label squat. Show all posts
Showing posts with label squat. Show all posts

Saturday, February 12, 2011

Leg Press Those Linemen?

Leg Press Those Linemen?


Leg Press Those Linemen rectusWith few exceptions muscles exert smaller tension at shorter lengths.
The rectus femoris muscles and wrist extensors are in deference to the above rule in some populations.
The rectus femoris is one of the four powerful quadricep muscles of the upper thigh. The rectus can flex the thigh at the hip and extend the leg at the knee.
In a seated position since the hip is flexed and the muscle is at a shortened length the action of extending a leg is primarily driven by the other three muscles of the quadriceps, the vastus lateralis, vastus medialis and vastus intermedius and less by the rectus femoris.
Biomechanically, you would think that the strength of the shortened rectus in knee extension would be weaker for everyone. Not true.
There are the aforementioned exceptions, thus the relationship between muscular strength and the tension a muscle can produce is very complex, especially across groups of individuals.bikeComparing cyclists with runners, you find the cyclist tend to be strong at a short compared to long rectus femoris length.
It has been argued that since cyclists have a shorter range of hip motion when cycling, compared to the range of motion of runners, that producing more tension at a shorter length is due to training. Other scientist argue that a strong rectus femoris in a shortened position is the result of genetics or of both genetics and training.
olineWhether the answer is training, inheritance or a combination of both, for the coach and athlete it raises an interesting conundrum about playing sports that require you to keep your knees bent.
When playing offensive line in football the position of choice is bending at the hip and knee. The lineman are also taught to slide their feet to keep an effective posture. They must be strong with their rectus femoris in a shortened position.
Knowing this, a leg press should be the tool of choice to agument strength.  Something for coaches and athletes to think about as they design their workout to Get Strong.

describe the image

Leg Press Those Linemen rectusWith few exceptions muscles exert smaller tension at shorter lengths.
The rectus femoris muscles and wrist extensors are in deference to the above rule in some populations.
The rectus femoris is one of the four powerful quadricep muscles of the upper thigh. The rectus can flex the thigh at the hip and extend the leg at the knee.
In a seated position since the hip is flexed and the muscle is at a shortened length the action of extending a leg is primarily driven by the other three muscles of the quadriceps, the vastus lateralis, vastus medialis and vastus intermedius and less by the rectus femoris.
Biomechanically, you would think that the strength of the shortened rectus in knee extension would be weaker for everyone. Not true.
There are the aforementioned exceptions, thus the relationship between muscular strength and the tension a muscle can produce is very complex, especially across groups of individuals.bikeComparing cyclists with runners, you find the cyclist tend to be strong at a short compared to long rectus femoris length.
It has been argued that since cyclists have a shorter range of hip motion when cycling, compared to the range of motion of runners, that producing more tension at a shorter length is due to training. Other scientist argue that a strong rectus femoris in a shortened position is the result of genetics or of both genetics and training.
olineWhether the answer is training, inheritance or a combination of both, for the coach and athlete it raises an interesting conundrum about playing sports that require you to keep your knees bent.
When playing offensive line in football the position of choice is bending at the hip and knee. The lineman are also taught to slide their feet to keep an effective posture. They must be strong with their rectus femoris in a shortened position.
Knowing this, a leg press should be the tool of choice to agument strength.  Something for coaches and athletes to think about as they design their workout to Get Strong.

describe the image

Wednesday, September 22, 2010

High or low reps that is the question?

High or low reps that is the question?

bigWith the advent of Life Sciences, Exercise Science is beginning to take a dramatic turn.

Scientists now have the capability to take training studies much further and compare the number of molecules developed from a training regime, tracking their respective pathways that elicit particular muscular responses.

They look at fancy stuff like P70s6k, GSK-3beta, Foxo1 and AKT signalling and the mTOR molecular pathway.

This takes the testing inaccuracy and bias out of the results. It says this is what happened when we counted or tracked the molecules.

The cool thing is you can find out what is going on even if the strength training protocol is not equivocally designed.

Studying the molecules has and will change what we think and what we think we know about exercise. The real science of exercise is just beginning.

big5In a recent study out of Australia at Deakin University, the researchers were looking at the pathways to hypertrophy and atrophy of skeletal muscle in humans.

They were looking at the AKT signaling. AKT is at the center of the chart on the left.

In order to compare and study the molecular responses to training they wanted disparity between the strength training groups.

When you do a study you want the results to show up so you can compare the two modalities in question..

To achieve this they decided to repeat the protocols on high and low repetitions as described in the current scientific literature on strength training. This way there would be no doubt about the results and make tracking of the molecular pathways easier.

The findings would be good stuff for a strength coach. They would know for certain if you do the following protocol, this is exactly what will happen at the cellular level.

describe the image This is much like the Kreb Cycle that the health professional learned as part of physiology classes.

They learned if you run aerobically a glucose molecule in the presence of oxygen enters the Krebs cycle and will give you 36 ATP and 2 ATP more from glycolysis. With this info the health professional can accurately tell you what is occurring when you run and design the appropriate distance or sprinting routine.

The Deakin University scientists thought they understood strength development and had one strength training group train with low repetitions and the other with high repetitions. The low repetition group did 3-5 reps for 4 sets, while the high rep group did 20-28 reps for 2 sets. The low rep group took 3 minutes rest between sets and the high rep group only had 1 minute rest between sets.

The exercises used in each group were the leg press, squat and leg extension.

describe the imageBased on the previous studies they were replicating the authors were sure that there protocols would give them disparity in results. The low repetition group would develop much more strength than the high repetition group. They would then report all the molecular changes based upon the protocols.

What they found was both groups had significant increase in hypertrophy, muscular strength and muscular endurance.

Which was exactly what they were not looking for.

Their study refuted just about everything that had been written regarding repetitions in strength training so far.

They did establish the role of AKT downstream signaling pathways in human skeletal muscle.

It also cleared up something that many strength coaches already empirically knew.....high big3repetition strength training gives you surprisingly tremendous results.

The key to developing strength is being systematic and progressive. Repetitions don't mean much to molecules other than providing mechanical tension. The cells sense the force and this tension changes cellular behavior.

High rep stuff is a great way to..... GET STRONG. big4