Biomechanics Question

[EIUvltr]

Anyone with experience in this field please reply.

I understand the concept of torque to be basically the further the weight from the muscle acting on it, the more the torque. I was wondering what the adaptive physiological differences were in lifts with high torque as opposed to lifts with lower torque. Such as bent arm dumbbell pullovers and straight arm dumbbell pullovers. Both work the LATs at the shoulder joint and Serratus anterior on the shoulder girdle, but the straight arm pullover has more torque. Thoughts?

[ADTF Academy]

Such as bent arm dumbbell pullovers and straight arm dumbbell pullovers. Both work the LATs at the shoulder joint and Serratus anterior on the shoulder girdle, but the straight arm pullover has more torque. Thoughts?

As far as I know torque is created not something that is just there.

The secondary question would be how much does the weight your lifting differ from straight arm and bent arm. Yes a longer lever (Straight arm) can provide more torque with force application being equal to that of a shorter lever (bent arm).

Now with the force application being the same it will infact apply more torque on your shoulder and Lats. The issue in my opinion is which is more specific to what your trying to do. In the vault do you want a bent arm on the pullover or straight arm. STRAIGHT ARM. So if you chose to do this exercise do it in a way that relates to what your attempting to do in your sport.

[EIUvltr]

I understand that you can do more weight with bent arm because of the lever principle, but the amount of force put on the shoulder joint is still the same because even though the resistance is more, the force arm is smaller for bent arm. And I understand that straight arm pullovers are more functional for a pole vaulter. But my question was what was the difference in the physiological adaptation of these two exercises?

[htheodore]

I understand that you can do more weight with bent arm because of the lever principle, but the amount of force put on the shoulder joint is still the same because even though the resistance is more, the force arm is smaller for bent arm. And I understand that straight arm pullovers are more functional for a pole vaulter. But my question was what was the difference in the physiological adaptation of these two exercises?

[htheodore]

I lost you on the last sentence. Clarify

[EIUvltr]

How does doing an exercise with a lot of torque affect the central nervous system and the musculature differently than an exercise that works the same muscles but with less torque?

[ADTF Academy]

I have been trying to find the EMG results for those two lifts. At this time I can not locate them. However, if the lats is your goal to work the lift that is recommended is the Bent Over Barbell Row.

This produced the greates EMG results for the Lat region of any lift they tested including the pullover.

[AVC Coach]

How does doing an exercise with a lot of torque affect the central nervous system and the musculature differently than an exercise that works the same muscles but with less torque?

Any exercise done with enough repetitions, regardless of amount of torque, will recruit the connection of more nerves to the actual muscles being worked. More nerves, more efficiency. Thus the old addage "Practice makes perfect".

As far as effecting the CNS, simply applying more torque to a muscle group shouldn't make a difference, but it can make the muscle and joint stronger through the given range of motion. Again, increasing repetitions will decrease the amount of time needed to relay messages back and forth from the CNS to the extremeties through the peripheral nervous system.

[jumpbackin]

I don't think muscles and nerve cells know anything about torque. They only know resistance, time, effort and repetion. In other words, If the same muscles are used, they don't know if it's more weight and shorter lever or less weight - longer lever. There's probably a slight difference in the muscles used, but it wouldn't be too significant.

I think a PVer should do them straight. The nervous system may remember to position and be more comfortable getting in that position for the vault. Also, it probably better prepares the shoulder joint (cartilage, tendons & ligaments).

[Robert schmitt]

This topic can get a little confusing. From what I see in your question is that the term "torque" can increase the stretch put on a muscle and assoc. tendons. This will create a stretch response in muscle spindles and golgi tendon organs which can increase the force of contraction (you will also have inceased force production from stored energy in the stretched connective tissue ("hysteresis" sp?). How ever most lifting techniques will minimize the muscle and tendon organ response because you typically slowly lower the wieght hold for a sec and then perform the lift. So it is actually traing your nervous system to inhibit the response.

Now, you create a stronger muscle conntraction neurologically from re enforcement of the stretch response. That is kind of some of the effect you get from plyos. etc.. not from the typical wieght lifting routine.

[EIUvltr]

This topic can get a little confusing. From what I see in your question is that the term "torque" can increase the stretch put on a muscle and assoc. tendons. This will create a stretch response in muscle spindles and golgi tendon organs which can increase the force of contraction (you will also have inceased force production from stored energy in the stretched connective tissue ("hysteresis" sp?). How ever most lifting techniques will minimize the muscle and tendon organ response because you typically slowly lower the wieght hold for a sec and then perform the lift. So it is actually traing your nervous system to inhibit the response.

Now, you create a stronger muscle conntraction neurologically from re enforcement of the stretch response. That is kind of some of the effect you get from plyos. etc.. not from the typical wieght lifting routine.

I agree with the muscle spindles, but the golgi tendon organ actually tells your muscles to relax, so I don't think they would contribute to a stronger contraction. But, your post kind of strayed from the torque question. Plus I don't think a muscle done with more or less torque necesarily puts a greater stretch on any muscle or tendon, I think it mainly refers to an increase in instability at the joint the weight is being lifted at. AKA shoulder joint and girdle for the pullover example. But that isn't the only example. A tall person doing squats experiences greater torque than a short person doing squats, I just want to know the differences in the effects of it.

[Lax PV]

The longer the lever, the longer the distance is from the axis of rotation (seems simple enough right?) So now kind of think of the teeter todder type of scenerio, if one person is very close to the axis, they had better weigh an awful lot, or they are not going to be moving much. Now kinda take that over to the weight training ideas...

The torque that you are producing by being in the position that you are in, will require the muscle to work harder to overcome that about of force. Almost all the joints in the body are what are called 3rd class levers, and without going into great detail, they don't work very effectivly so the muscle actually ends up providing a force that is much greater than the force that the weight would offer based on insertion sites of muscles and things like that.

Physiologically, I would say that using a longer lever (or increasing the torque) would work force your muscle to work harder. As far as EMG goes, an EMG reading will have nothing to do with the amount of force that is created, it is simply a measure of electrical activity in a given muscle. Now there are in fact ways around that so one could get a rough estimate about how hard a persons muscle is working vs. a voluntary maximum contraction--but thats still just an estimate.

Thats a little bit of the biomechanics of it, as far as the physiology is concrened, thats all I've got, as I am mechanics guy, not physio. Hopefully this kinda makes sense.