Comparisons and conclusion

Work

Incline: Work=322.923J Power= 645.846 watts
Decline: Work= 374.678J Power=1023.710 Watts
Flat: Work=370.0585J  Power=652.660 Watts


Comparing all three, it is pretty clear which one generated the most power.  Decline by far generated the most power, it had the greatest acceleration and since the distance wasn't that large, the time it took to the complete the lift was relatively short.  Incline and flat were nearly identical in power although incline required less work.  


Conclusion


In a physical sense, there really isn't an accurate way to incorporate the angles of the bench and how it affects the actual lift.  The lift itself is determined by a simple up and down motion and what affects the work and power in a physical sense is simply how fast you are able to move the mass and the total distance it takes.  The issue with looking at this problem at a physical sense is that when you try to incorporate the angles, the forces are already balanced and the press doesn't utilize the angles in that sense since it is a straight up and down movement.  

The image above does a good job representing the issue.  The top box can be seen as the forces acting on the barbell.  The box on the incline represents the person on the bench at an angle.  As you can clearly see, both are independent of each other in the forces sense.  

Incline Bench Press

The incline bench press is another common pressing technique that has the lifter at an inclination.  As with the decline bench, the actual incline doesn't have a direct influence on the pressing as the angle affects the presser and the forces are balanced on the presser.  So, as before, the equation is the same, but the distance is required to press is least of all three presses.  The distance required to complete a repetition it 47 cm and the work required to complete a repetition ended up being 322.923J.  The power based on the time of the repetition (.5) would make the power generated from the lift 645.846 watts.

Decline Bench press

The next lift is the decline bench press.

This lift is as it is named, the bench press but down a declined slope.

The decline bench we were using was at a 45 degree angle downwards.  This 45 degree angle changes the way the forces affect the lifter, instead of the forces being balanced upwards and downwards, there is also a friction keeping the person in place.  This degree really doesn't affect the actual pressing motion.  The actual pressing motion is a straight up and down motion opposing the force of gravity, but is greater

.  The sum of the forces is equal to the work being done by the press, therefore, the equation to find the work and power is the same.  The work equals 374.678J and the total power generated in the lift is 1023.710 Watts

Flat bench

Flat Bench




The flat bench press is probably the most common lift and is a lift that is done in competitive power-lifting.  The motion of the flat bench is a straight up and down motion done at no angle.

The equation for work done for the flat bench would simply be W=FD, F being the force (N) and D being the displacement from the starting point (m).  To find the net force applied, it is equal to mass x acceleration. Based on this equation, it would make sense that the greater the distance the more work required implying that the lift with the shortest bar path must be the easiest to accomplish.

From the video analysis, it appears that the velocity was increasing constantly therefore there is constant acceleration.  The acceleration I derived was 4.241m/s^2.  I calculated this by using this equation : (Vf-Vi)/T.  Since the sum of the forces is in an upward direction, the equation would be ma + mg =Wp.  The reason being if you at the FBD, it is simply gravity downward, with a greater Force push upwards.  This force push is equal to that of the work being done.  adding the net force and the force of the mass, you can find the total newtons.  The total newtons I derived was 648.224.  This was my F, and then I multiplied this by .57 which was the distance to get 370.0585.  The power is the work divided by the time.  The time is .567.  The total watts generated from the lift is 652.660 Watts.

Introduction

Hello viewers!  Welcome to my blog.  In my blog I aim to focus on the physics of weightlifting and how to maximize your strength.

For my first blog post, I want to go over my first physics based weightlifting experiment.

The purpose of my experiment is to find out which bench press requires the least work done and which one generates the most power.  This is important for people trying to maximize strength gains as the less work required allows for more repetitions of the weight, but could also in turn lower the power rating.  The more work the more power that could be potentially generated, but since there is more work required and the closer you get to a maximal lift, the slower the repetition therefore causing less power.


Predictions

There are 3 main bench presses, the incline, decline and flat.  I would like to know which lift you are capable of doing the most work and able to exert the most power.

Based on the angles of the lift and the distance of the bar path, I hypothesized that the decline bench would be conducive to producing the most power and requiring the least amount of work.