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50 51 52 QUESTION 2 Q 2(a) On a force -length diagram, sketch the following: (i) Characteristic for passive muscle (0 % Activation) (ii) Characteristic for activated muscle (50% Activation) (iii) Characteristic for activated muscle (100% Activation) Q 2(b) Given the data tabulated below (Table 2.1): Sketch the position of the leg (foot, lower leg, upper leg) at Frame 50 [1 mark] Calculate the angle of the upper leg in space at Frame 50. [2 marks] Calculate the angle between the upper and lower leg at Frame 50 [2 Marks] Table 2.1 Filtered Marker Kinematics Marker Hip Knee Ankle Heel Ball Frame Time x (m) y (m) x (m) x (m) x(m) y (m) x (m) y (m) 0.672 1.3931 0.8300 1.3859 0.5141 1.2433 0.0489 1.3997 0.0436 0.686 1.4083 0.8279 1.3937 0.5123 1.3046 0.1005 1.2445 0.0494 1.3998 0.0344 y (m) y (m) 1.3034 0.1000 48 49 Foot (i) (ii) Q 2(c) From the data tabulated above (Table 2.1), calculate: (i) linear velocity of the knee at Frame 50. (ii) linear acceleration of the knee at Frame 50. 0.701 1.4239 0.8255 1.4018 0.5105 1.3059 0.1009 1.2460 0.0498 1.4001 0.0343 -9.6 400.3 0.715 1.4400 0.8230 1.4102 0.5089 1.3074 0.1014 1.2477 0.0504 1.4006 0.0342 -3.8 418.8 2.2 441.0 0.729 1.4564 0.8204 1.4188 0.5077 1.3090 0.1020 1.2494 0.0516 1.4014 0.0340 Segment Q 2(d) [11 Marks] With reference to the data given in Tables 2.1 and 2.2, calculate the joint reaction forces and moment about the ankle joint at frame 50, if the centre of pressure acts at the ball of the foot. Table 2.2 Anthropometric and Kinematic Data (Frame50) Mass Centre of Mass (Proximal) (kg) 1.16 [TOTAL MARKS: 25] [3 Marks] (m) Mid-point between Heel and Ball Radius of Gyration (about C. of M) (m) 0.475 [End of Question 2] MM228-Biomechanics of Human Movement August/Resit Examinations 2018/2019 GRF A-P Vert. -16.8 375.0 -14.5 386.1 ax (C. of M) (m/s²) 6.40 [3 Marks] [3 Marks] ay Cz (C. of M) (C. of M) (m/s²) 2.88 (1/s²) -49.61 Page 4 of 8