Mathematical Analysis-Thursday March 30th, 2017

This is the equation for Garg's Method! But don't worry its less intimidating than it looks. The first section of the equation requires the summation of the energy of position multiplied by time. Position is basically standing or sitting. Since it takes certain energy to stand or sit this must be factored into the overall energy for the job. For both squats, the position is standing. The second part of the equation requires the summation of the change in energy of all tasks. For the lifts in my research this can be broken down to two motions: the lift and the arm raise. Since I lifted both boxes to the same height, the energy used in the arm raise will be the same for both the stoop and squat lift. The lift motion accounts for the energy until the load reaches 0.81 meters or hip height. Once the load reaches that height the arms begin lifting the load to its final height(in this case 1.42 meters). Calculating the energy for the squat and stoop lift requires two other equations that are impacted by initial height, final height, body weight, load weight, and sex(male or female). The equation for arm raise requires a very similar equation, but it isn't necessary here because it is the same for both lifts.

In my case, initial height was zero because I lifted the load from the ground. For these two equations, final height was 0.81 because I lifted the load above my hips. The variable S represents sex. Insert a 1 for a male subject and 0 for a female subject. The box that I lifted weighed 20 kg. I found time of lift by looking at how many frames of data were captured by the Vicon system. The stoop lift took longer at 353 frames or 3.53 seconds. The squat lift ended in 3.19 seconds. After calculating this all out, I found that the squat lift requires 18.629 kilocalories per minute while the stoop lift only requires 13.139 kcal/min. It is interesting to note that the stoop lift requires less energy despite being considered the inferior lift, but more on this next week!