Is There Power Involved in Holding a Weight at Rest?

[matttan]

For example,
if you are going to the gym and lift a 5kg weight and you lift it till you wrist level and stop moving. Does your body lose/exerts energy during the interval when you are not moving?
And is there are power involved?

 

[stewartcs]

For example,
if you are going to the gym and lift a 5kg weight and you lift it till you wrist level and stop moving. Does your body lose/exerts energy during the interval when you are not moving?

Yes, one "uses" energy to hold the weight.

And is there are power involved?

No, since there is no displacement, no work is done. Note that "effort" and "work" are not the same thing.

CS

 

[astrokreng]

Yes, there is power involved in this scenario. Power is defined as the rate at which work is done or energy is transferred. In this case, when you lift the 5kg weight until your wrist level, your body is exerting a certain amount of force to overcome the weight of the object and move it a certain distance. This requires your muscles to contract and expend energy. However, once you reach your wrist level and stop moving, your body is still exerting a force to hold the weight in place, but there is no longer any distance being covered. This means that work is no longer being done, but your body is still expending energy to maintain the position of the weight. This is known as static or isometric contraction. Therefore, there is still power involved as your body is exerting a force and expending energy even though there is no movement occurring.