Exam 12 August, questions PDF

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2017 Past Paper...

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EXSS2018 Biomechanical Analysis of Movement Mid Semester Exam

Student Name: _____________________________

Student Number: ____________________________

UNIT OF STUDY:

EXSS2018

Biomechanical Analysis of Movement

DATE:

Wednesday 3rd May 2017

TIME:

11.00 AM

NUMBER OF MARKS:

30

NUMBER OF QUESTIONS:

15 MCQ and 5 Short Answer

NUMBER OF PAGES:

13

INSTRUCTIONS: 1. CHECK that you have all questions and pages 2. Answer all questions on the exam paper 3. READ the directions carefully before answering. 4. ATTEMPT all questions. 5. This paper consists of TWO SECTIONS: multiple choice questions and short answer questions. 6. Use the MCQ computer form to answer multiple choice questions. 7. Write short answer questions directly onto this exam paper, using the spaces after each question.

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Anthropometric Table: Taken from: Winter, David A (2009) Biomechanics and motor control of human movement – 4th Edition. New Jersey, John Wiley & Sons

2

Equations Sheet vf = vi + a ∙ t

impulse = ∆momentum

vf2 = vi2 + 2 ∙ a ∙ ∆s

� Fx = m ∙ a

1 a ∙ t2 2

� Fy = m ∙ a

∆s = vi ∙ t + T=F×d

walking speed (m s−1 ) =

cadence(steps per minute) × stride length (m) 120

walking speed (m s−1 ) =

stride length (m) stride time (s)

stride time (s) =

time (s) number of strides

120 × walking speed (m s−1 ) stride length (m) = cadence(steps per minute)

centre of massx = centre of massy =

(x1 × m1 ) + (x2 × m2 ) + (x3 × m3 ) + ⋯ m1 + m2 + m3 + ⋯

(y1 × m1 ) + (y2 × m2 ) + (y3 × m3 ) + ⋯ m1 + m2 + m3 + ⋯

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PART A. Multiple Choice Questions: Please circle the correct answer 1. Fourier Analysis is a mathematical process that allows us to:

(B) Remove high frequency errors from a signal (C) Remove errors resulting from low frequency noise in a signal (D) Correct errors in a signal that result from too low a sampling frequency (E) Correct errors that result from an inappropriate shutter speed on the camera

2. Which of the following filters would best correct a systematic error in digitising a walking motion?

(A) A low pass filter with cut-off frequency of 6 Hz (B)

A low pass filter with cut-off frequency of 12 Hz

(C)

A high pass filter with cut-off frequency of 6 Hz

(D) A high pass filter with cut-off frequency of 12 Hz (E)

None of the above filters would be able to correct systematic errors

3. Which of the following statements are correct?

(A) A material with a high modulus of elasticity can have low strength and high ductility yet is a brittle material (B) A material with a high modulus of elasticity can have high strength, high ductility and high fracture toughness

(D) A material with a high modulus of elasticity can have high strength, low ductility and low fracture toughness (E) B and D can both be correct

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4. A low pass filter will:

(B) Remove low frequency noise from a signal (C) Not be suitable for processing kinematic data (D) Correct errors resulting from improper calibration (E) Answers A and B are both correct

5. Which of the following statements best describe the concept of Wolf’s Law?

(A) Tissues loaded at a higher rate can withstand increased load to failure and store more energy before failure

(C) Bone mineral density is affected by nutritional status (D) The rate of loading on a tissue will affect the maximum strength of the tissue (E) The rate of loading on tissue can affect the viscous properties of the tissue

6. Consider the following diagram of an arm. Use the anthropometric table provided to estimate the location of the centre of mass of the entire upper limb, treating this as a single segment. Give the distance from the shoulder to the centre of mass of the limb.

(A) 2.9 cm

30 cm

(B) 3.9 cm (C) 15.9 cm 28 cm (D) 30.7 cm 19 cm

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7. Which of the following statements are TRUE?

The use of a biomechanical model in two dimensional digitising is important because….. (A) The model accounts for errors produced by digitising inaccuracy. (B) There are too many bones in the body for us to measure the individual movement of every one. (C) They ensure that all bones are accounted for in the kinematic measurements.

(E) All of the above statements are correct.

8. Which of the following statements is FALSE? When the shutter speed on a video camera is changed from 1/50 sec to 1/250 sec:

(A) The image appears darker (B) Segments of the body will move through a smaller distance or range of motion during the time that the shutter is open

(D) It reduces the chance that fast moving segments of the body will appear blurred or streaked (E) None of the above options are false

9. Which of the following would result from filming a movement with a frame rate that is too slow?

(A) Blurring of the images as a result of movement while the camera shutter is open (B) Too many images would need to be digitised, with a consequent cost in time

(D) Parallax error would be increased (E) Increased perspective error is likely to result

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10. When filming a movement for later digitising, where should the scaling object be positioned to maximise accuracy?

(A) As close as possible behind the movement so that it is visible in every video frame (B)

In exactly the same plane as the movement being filmed

(C)

Positioned so that the desired movement covers the area defined by the calibration object

(D) Answers A, B and C are all correct

11. Which of the following provides the best overall summary of the steps involved in a Qualitative Analysis?

(B) 1. Observe the performance. 2. Measure the factors of performance. 3. Identify all errors. 4. Quantify all errors. (C) 1. Establish a fundamental knowledge of the skill. 2. Identify the primary goals of the skill. 3. Identify characteristics of ideal technique. 4. Perform a determinant analysis. (D) 1. Consider the ideal conditions for viewing the performance. 2. Break the movement into key events. 3. Identify key phases of the movement. 4. View the movement multiple times considering different body parts each time. (E) 1. Identify the exact performance variable. 2. Break this variable into components. 3. Assess relative importance of each component. 4. Measure the subject’s performance on each component.

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12. The following graph illustrates the pattern of knee extensor moment produced during a rowing movement.

KNEE MOMENT (Nm)

DRIVE PHASE

RECOVERY PHASE

200

100 EXTENSION 0 0

25

50

75

100

FLEXION -100 Time (% Stroke) Which of the following statements best describe the torque at the knee just after 25% of the stroke cycle

(A) The extensor muscles produce an eccentric torque at this time

(C)

The flexor muscles produce an eccentric torque at this time

(D) The flexor muscles produce a concentric torque at this time (E)

The flexor and extensor muscles co-contract equally to provide balance about the joint

13. In which of the following conditions would it be essential to use three-dimensional film analysis instead of measuring in only two dimensions?

(A) When there are significant movements along two axes of motion (B)

When there are significant movements in two planes of motion

(C)

When there are significant rotations occurring around two axes of rotation

(D) Answers A and B are both correct

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14. Which of the following statements provides the best description why it is easier to perform a lat pulldown exercise with the hands closer together?

(A) The shoulders are more flexed with the hands together, making it easier to produce the required torque about the shoulder (B)

The shoulders are more abducted with the arms apart, making it easier to produce the required torque about the shoulder

(C)

For the same amount of weight being lifted, the torque generated about the shoulder joint by the adductor muscles is greater with the hands closer together

(D) For the same amount of weight being lifted, the torque generated about the shoulder joint by the adductor muscles is less with the hands closer together

15. Which of the following can be considered advantages of qualitative analysis over quantitative?

(B)

Greater accuracy can be achieved with qualitative analysis because it is not subject to measurement error

(C)

Qualitative analysis can be performed by sport scientists without having a strong understanding of the movement being analysed

(D) Answers A and B are both correct (E)

Answers A, B and C are all correct

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PART B. Short Answer Questions. Answer all questions in the space provided 16.

Below is part of a deterministic model for a running race. Fill in the empty boxes to provide reasonable factors determining the duration of the race. Note: there is more than one “reasonable” answer for each box. A judgement will be made as to whether your answers are reasonable, not whether they matched exactly with a standard solution. (2 marks)

Total Race Time

Time during start

Accell

Time spent running

Striding

Finishing

17.

A 54 year old woman has been prescribed exercise to slow the development of osteoporosis. (A) What type of exercise has been shown to be most effective at developing bone mineral density? (1mark)

(B) Explain the process that occurs once the woman commences her exercise program. (2 marks)

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18.

The picture below shows the x and y coordinates of the centre of mass of the thigh, shank and foot. The person in the picture has a total body mass of 80 kg. (A) Use the anthropometric table provided to estimate the mass of each segment in kilograms. (1 mark)

(B) Use the position of the thigh, shank and foot, together with the relative mass of each segment, to calculate the location of the centre of mass of the whole leg. Note: diagram is not drawn to scale. Use the coordinate locations provided for each segment. (2 marks)

Shank (0.35, 0.5) Thigh (0.1, 0.6) Foot (0.55, 0.2)

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19.

(A) What does the term DUCTILE mean? (1 mark)

(B) Explain how the anatomic structure of compact bone increases its FRACTURE TOUGHNESS. (2 marks)

PLEASE TURN THE PAGE

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20.

Consider the following diagram of a person performing a knee extension exercise against a resistance of 200 N. The knee is flexed so that the line of the shank is 50° below the horizontal, and the 200 N force is located a distance of 45 cm along the shank from the knee joint. The shank and foot have a weight of 42 N and the centre of mass is located a distance of 27 cm from the knee joint. The moment arm of the patella tendon is 4.5cm.

45 cm

50 deg

27 cm

42 N 200 N

(A) How much torque is exerted about the knee by the 200 N load force and the weight of the lower leg if we assume the system is in equilibrium? (2 marks)

(B) How much force do the quadriceps muscles exert through the patella tendon? (2 marks)

END OF EXAM 13...