CSUN CSUN Student C - Quiz: Final canvas.csun.edu/courses/134928/quizzes/493970/take CSUN Fall 2023 Home Assignments Question 13 See figure 3 below: F_quad M C Answer in the order of questic + 12 pts Account Discussions Grades Dashboard People Files Courses Syllabus Groups Quizzes Modules Calendar BigBlueButton Collaborations Inbox Chat History Follett Discover Record Name Studio Roster Recording Canvas Insights Help & Library Panopto Video Resources 11 Answer in the order of questions 1 through 12. Look graphs below on the same module A person executes a knee extension. The fitness instructor wants to analyze the force requirement on four different positions. The weight of the external weight along with the weight of the tibia and foot is 40 lbs, so Weight W-40lbs. The line defined between the Knee and the Center of Mass (COM) (of the tibia-foot-and external weight system) is measured and it is Knee_to_Com = 25 inches. Position A is the starting position and the Knee_to_Com line is on top of the vertical cartesian line (angle theta_1=0). Position B is when the Knee_to_Com line is at 30 degrees from the vertical cartesian line (angle theta_2=30) Position C is when the Knee_to_Com line is at 60 degrees from the vertical cartesian line (angle theta_3=60) Position D is when the Knee_to_Com line is at 90 degrees from the vertical cartesian line (angle theta_4=90). C D A B K BryteWave Course Materials Office 365 Zoom Knee Knee Knee Knee N CSUN CSUN Student C - Quiz: Final canvas.csun.edu/courses/134928/quizzes/493970/take CSUN Fall 2023 Home Assignments Discussions Account Grades Dashboard People Files Courses 18 Groups Syllabus Quizzes Modules Calendar BigBlueButton See figure 3 below: F_quad M C Answer in the order of questic x A B Knee Knee 11 COM COM D Knee Knee Collaborations Inbox Chat History Follett Discover Record Name Studio Roster Recording Canvas Insights Help & Library Panopto Video Resources K BryteWave Course Materials Office 365 Zoom Calculate the moment arm of the resistance (Resistance arm = RA) of the external weight for positions A, B, C, D, as well as the torque T_weight created at the knee because of the weight at these positions. 1) Position A -> Resistance Arm, RA_1=? inches 2) Position B -> Resistance Arm, RA_2= ? inches 3) Position C -> Resistance Arm, RA_3= ? inches 4) Position D -> Resistance Arm, RA_4= ? inches 5) T_weight_1=RA_1*W = ? lb.in , 6) T_weight_2=RA_2*W = ? lb.in , 7) T_weight_3=RA_3*W = ? lb.in , 8) T_weight_4=RA_4*W = ? lb.in The best way to see the problem is to solve it in a position of the tibia between A (vertical) and D (horizontal). So see figure 2 below Resistance Arm = RA N CSUN CSUN Student C - Quiz: Final canvas.csun.edu/courses/134928/quizzes/493970/take CSUN Fall 2023 Home Assignments Account Discussions Grades Dashboard People Files Courses 18 Groups Syllabus Quizzes Modules Calendar BigBlueButton Collaborations Inbox Chat History Follett Discover Record Name Studio Roster Recording Canvas Insights Help & Library Panopto Video Resources K See figure 3 below: F_quad M C Answer in the order of questic x Calculate the moment arm of the resistance (Resistance arm = RA) of the external weight for positions A, B, C, D, as well as the torque T_weight created at the knee because of the weight at these positions. 1) Position A -> Resistance Arm, RA_1= ? inches , 5) T_weight_1=RA_1*W = ? lb.in 2) Position B -> Resistance Arm, RA_2= ? inches , 6) T_weight_2=RA_2*W = ? lb.in 11 3) Position C -> Resistance Arm, RA_3= ? inches , 7) T_weight_3=RA_3*W = ? lb.in 4) Position D -> Resistance Arm, RA_4= ? inches , 8) T_weight_4=RA_4*W = ? lb.in The best way to see the problem is to solve it in a position of the tibia between A (vertical) and D (horizontal). So see figure 2 below Knee Resistance Arm = RA Knee e COM COM RA sin(0)=opposite/hypotenuse => sin(0)= RA/Knee_COM => RA=sin(e) * Knee_COM BryteWave Course Materials Office 365 Zoom To hold the tibia in a static position the quadriceps muscle is contracting in an isometric condition. Therefore the torque created by the weight should be balanced by the torque generated by the quadriceps muscles. T_weight=T_quads. N CSUN CSUN Student C - Quiz: Final canvas.csun.edu/courses/134928/quizzes/493970/take CSUN Fall 2023 Home Assignments Account Discussions Grades Dashboard People Files Courses Syllabus Groups Quizzes Calendar Modules BigBlueButton Collaborations Inbox Chat History Follett Discover Record Name Studio Roster Recording Canvas Insights Help & Library Panopto Video Resources K 11 See figure 3 below: F_quad M C Answer in the order of questic To hold the tibia in a static position the quadriceps muscle is contracting in an isometric condition. Therefore the torque created by the weight should be balanced by the torque generated by the quadriceps muscles. T_weight=T_quads. T_weight=RA*W T_quads = EA * F_quad => F_quad = T_quads / EA = => F_quad = T_weight/EA or RA*W = EA F_quad => F_quad = W * RA/EA See figure 3 below: Moment Arm or Effort Arm - EA F_quad Knee RA W COM T_weight=T_quads. T_weight=RA*W T_quads = EA * * F_quad RA*W = EA*F_quad => F_quad = W* RA/EA BryteWave Course Materials Office 365 Zoom An orthopedic doctor calculated the average Effort Arms EA of the quadriceps for different positions and created a table. The fitness instructor using the table records that the effort arms (EA) in different positions are as following N CSUN CSUN Student C - Quiz: Final canvas.csun.edu/courses/134928/quizzes/493970/take CSUN Fall 2023 Home See figure 3 below: F_quad M C Answer in the order of questic Assignments Account Discussions An orthopedic doctor calculated the average Effort Arms EA of the quadriceps for different positions and created a table. The fitness instructor using the table records that the effort arms (EA) in different positions are as following Grades 11 Dashboard People Position A effort Arm Position B effort Arm Position C effort Arm Position D effort Arm EA_1 = 0.2 inches EA_2 = 0.3 inches EA_3 = 0.4 inches EA_4 = 0.25 inches Files Courses Syllabus Groups Quizzes Modules Calendar Calculate the force of the Quadriceps muscles F_quad in the equivalent of lb: 9) Position A Quadriceps muscles F_quad_1 = ? lb, 10) Position B Quadriceps muscles F_quad_2 = ? lb, 11) Position C Quadriceps muscles F_quad_3 = ? lb, 12) Position D Quadriceps muscles F_quad_4 = ? lb, BigBlueButton Collaborations Inbox Chat 1) Position A -> Resistance Arm, RA_1=? 0 > History Follett Discover Record Name Studio 2) Position B-> Resistance Arm, RA_2= ? inches 12.5 Roster Recording Canvas Insights Help & 3) Position C -> Resistance Arm, RA_3= ? inches 21.65 Library Panopto Video Resources Materials Office 365 BryteWave Course 4) Position D -> Resistance Arm, RA_4= ? inches 25 K Zoom 5) T_weight_1=RA_1*W = ? lb.in 0 N CSUN CSUN Student C - Quiz: Final See figure 3 below: F_quad M C canvas.csun.edu/courses/134928/quizzes/493970/take CSUN Fall 2023 Home 1) Position A -> Resistance Arm, RA_1=? 0 2) Position B -> Resistance Arm, RA_2= ? inches 12.5 Answer in the order of questic x Assignments Account Discussions Grades 3) Position C -> Resistance Arm, RA_3= ? inches 21.65 11 Dashboard People 4) Position D-> Resistance Arm, RA_4= ? inches 25 Files Courses Syllabus 5) T_weight_1=RA_1*W = ? lb.in 0 Groups Quizzes Modules 6) T_weight_2=RA_2*W = ? lb.in 500 Calendar BigBlueButton Collaborations 7) T_weight_3=RA_3*W = ? lb.in 866..02 Inbox Chat 8) T_weight_4=RA_4*W = ? lb.in History Follett Discover 1000 Record Name Studio Roster Recording 9) Position A Quadriceps muscles F_quad_1 = ? lb 0 Canvas Insights Help & Library Panopto Video 10) Position B Quadriceps muscles F_quad_2? lb [Choose ] Resources K Materials Office 365 Zoom BryteWave Course 11) Position C Quadriceps muscles F_quad_3? lb [Choose ] 12) Position D Quadriceps muscles F_quad 4 ? lb [Choose ] > > N