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TECHNOLOGIES FOR MOTOR BEHAVIOUR ANALYSIS AND VIRTUAL MODELLING July 26, 2018 EXERCISE 1 [6/30] A subject performs a jump on the force platform represented in Fig.1, having the sensor S2 as origin. The vertical output Ry represents the global reaction force of the platform along the y axis (the center of pressure cp lies on the upper face of the platform). At the end of the pushing phase, reaction vector R has a magnitude of 2000N. R is the result of the vertical component Ry, plus the lateral reactions Rx and Rz. Figure 1 1.1 Determine Rx , Ry and Rz at the end of the pushing phase considering θ = 5° and ϕ = 10°. 1.2 Calculate the mass of the subject knowing that Ry shows a trend as in Fig.2, where the dashed area represents the integral of the force exerted by the subject along the y-axis over time and is equal to 600Ns. Figure 2 EXERCISE 2 [5/30] An EMG signal acquisition is performed at the lower limbs of a subject during a normal walk. In Fig.3, the EMG signal of the right hamstring muscle is presented in a time window of 7 secs while in Fig.4 the power spectral density is presented. Describe the signal highlighting: 2.1 The muscle activation over time in Fig. 3 and the frequency components related to it in Fig.4 2.2 Unwanted components, if any (noise, baseline drift, low frequency oscillation etc. in both the Figures) 2.3 The possible sources for periodic components of point 2.2 (check out Fig. 3) 2.4 The envelope of the signal has to be detected, describe all the steps you need to perform in order to do that considering the presence of unwanted components and the methods you would use. Figure 3: EMG signal over time Figure 4: EMG power spectral density EXERCISE 3 [4/30] Considering the EMG signal of Exercise 2, suppose you want to repeat the test removing all…