[quote]bilski wrote:
Here’s a few questions for the math physics guys just off the top of my head…just throwing shit out there…
- Is peak force the sole factor outside of innate mechanical advantage/technical skill or specific weakness determining whether a lift is complete or not?
- Can one PR without increasing their peak power in the context of the above?
- Other than form or muscle weakness how might that occur?
- Are there factors such as Motor Unit Efficiency and ROFD that affect acceleration as a variable of force?
- If the standard template among most elite lifters is to train the actual lift with less than 90% for a majority of the cycle, how do they improve?
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Peak force is not the most important factor in a max lift. A sprinter exerts a much higher peak force than a 1000 pound squatter. A basketball player exerts more. A 1.2 meter vertical jump (about 48 inches) requires the jumper to leave the ground at 4.8-4.9 meters per second. A typical basketball player will have less than a .35 meter jump “stroke” and if they weigh 220 pounds they will have to accelerate at about 33.6 m/s squared. That would require about 750 vertical pounds of force over that .35 meter stroke above the 220 needed to hold that bodyweight against gravity. In other words it would be the same force as a 220 pounder “just moving” 750 pounds for the top .35 meters. Peak forces in vollyball jumps have shown forces equal to 10 Gs, or a 220 pound person exerting 2200 pounds over a short duration.
http://www.jssm.org/vol9/n2/17/v9n2-17pdf.pdf
Now the force on the muscle is affected by mechanical advantage based on the joint angles so its not the same force as at the bottom of a 750 squat.
Peak force is not the key. Notice also by the way that the jumpers experienced 2 peaks in force. One almost immediatly due to the stretch reflex and the other hundredths of seconds later as they reach the optimal speed in the force-velocity curve. Olympic lifters, as I have mentioned before show the same thing, which is why we get a natural first and second pull. If you pull fast at the beginning the speed can feedback to slow you down.
The thing about peak force in powerlifting, and plyometrics as Hatfield believed in is that plyometrics allow the force on the tendons to rise fast (high jerk) before the the tendon inhibits higher force production so the tendon adapts and becomes less deformable, and or possibly less sensitive to deformation and allows force generation to go a little higher.
I really think that Westside misunderstood the Russian research but came upon a plyometric effect of tendon adaptation as a result. The main reason for CAT is to teach your body to continue to uncrease force even with some speed as speed inhibits force production. So CAT lets olympic lifters exert force at higher speed and continue to add speed to the bar. They did not however mix the notion of CAT with plyometrics which were a different training method designed to increase maximum force that a muscle/tendon will allow by resisting deformation of the tendon. Their fast training was not plyometric. Their plyometric training did not involve pushing at maximal speed, they focused only on the brief reversal period of muscle contraction.
“Speed” training alone (say from a dead pause under load) helps if during a max press the bar speed gets high enough that your muscles will not voluntarily contract as hard due to the speed reflex inhibition. The plyometric effect (and again I’ve shown that vollyballers experience 10 Gs of force which pretty much defeats the argument that maximal force takes significant time to develop) I believe raised your resistance to producing maximal force by quickly deforming the tendons before they can reflexively shut down contraction).
A bench press and a squat are plyometric anyway. I think that in a 300 pound max bench studies show that there are momentary forces at reversal of 330-360 pounds. We do know form olympic lifts which are fast that there is high speed inhibition at the bar speed range of a clean or snatch so training to push harder on an already moving bar seems to me to have merit, but in part it helps with shirts and suits because the equipment is helping to give the bar speed.
And also who cares really if you push the squat harder and harder for the entire ROM. If you get past 3-5 inches above parallel you should have the lift completed. Only with a suit does the sticking point of the squat rise up to maybe the level of a half way to parallel squat.
Another part of one of your questions. I think that Hatfield claimed that you run out of stores of CP and ATP with .5 seconds of exertion on a maximal squat. So it would seem that you can increase your max by increasing stores of phosphates, and enzymes that restore phosphates. If you have all the phosphates you need you can squat X-hundred pounds with X-hundred pounds of force. Since you run out, you need to have bar speed on your side when you run out and are left with what you can resynthesize.
What is ROFD? (guessing: range of function something?).
I think the main reason people physically fail at a weight is because their supportive muscles can not hold on to allow force to transfer with a past max weight. Again a 300 pound bench presser exerts 330-360 pounds at reversal, but if you put 330 on the bar I think that their support and stabilizers can’t hold on (long). Speed helps here too. The lifter may exert 330-360 for a brief period at reversal and if the lift is on its way then the stabilzers have time to restore. With the squat its usually the core muscles that fold. With the bench its probably shoulder stability.
