WEEK 1

Question 1

What are the three key objectives when studying arm action in vertical jump performance?

Answer 1

1. Quantify effects of arm swing on jump height. 2. Calculate joint kinetics during take-off. 3. Identify contributions of ankle, knee, and hip extensors.

Question 2

What does BSIP stand for, and why is it used in biomechanics?

Answer 2

BSIP stands for Body Segment Inertia Parameters. It is used to determine segment mass, dimensions, centre of mass location, and moment of inertia.

Question 3

What is the centre of mass?

Answer 3

The point where all the mass of an object is concentrated and the weight force acts.

Question 4

Name two types of motion capture methods.

Answer 4

1. Optical methods (e.g., VICON). 2. Inertial systems (e.g., IMUs).

Question 5

What is parallax in motion capture?

Answer 5

The apparent shift in position of an object when viewed from different angles, causing measurement errors.

Question 6

What are active and passive motion capture systems?

Answer 6

Active systems use LED markers (e.g., CODA), while passive systems use reflective markers (e.g., VICON).

Question 7

What is differentiation in biomechanics?

Answer 7

Differentiation is the rate of change of a variable (e.g., velocity is the rate of change of displacement).

Question 8

What is the purpose of filtering kinematic data?

Answer 8

To reduce noise and improve accuracy, often using a low-pass filter.

Question 9

Name two types of filters used in biomechanics.

Answer 9

1. Non-recursive filter (e.g., 3-point moving average). 2. Recursive filter (e.g., Butterworth filter).

Question 10

What is a joint moment?

Answer 10

The net effect of all the forces acting to rotate a joint.

Question 11

What is quasi-static analysis (QSA)?

Answer 11

A method that assumes the body is static at each instant, using simple calculations for joint moments.

Question 12

What is inverse dynamic analysis (IDA)?

Answer 12

A method using kinematic data and external forces to calculate joint moments dynamically.

Question 13

What is a Free Body Diagram (FBD)?

Answer 13

A diagram showing all forces and moments acting on a body segment.

Question 14

What are joint reaction forces (JRF)?

Answer 14

Forces acting at a joint due to internal and external loads.

Question 15

What equation is used for torque in IDA?

Answer 15

A: τ = Iα (Torque = Moment of Inertia × Angular Acceleration).

Question 16

What is the formula for joint power?

Answer 16

Joint Power = Joint Moment × Angular Velocity.

Question 17

What does positive joint power indicate?

Answer 17

Positive joint power indicates energy generation.

Question 18

What is work in biomechanics?

Answer 18

Work = Power × Time (measured in Joules).

Question 19

What are degrees of freedom (DoF) in motor control?

Answer 19

The number of independent components (muscles/joints) that can vary in motion.

Question 20

What is coordination in motor control?

Answer 20

The organization of body parts to achieve movement goals.

Question 21

What is functional variability?

Answer 21

Variability that allows adaptation and flexibility in movement.

Question 22

What is coordination?

Answer 22

The relationship between two movement angles or patterns

Question 23

What are angle-angle diagrams?

Answer 23

Graphs that show the relationship between two joint angles.

Question 24

What is intra-limb coordination?

Answer 24

Coordination between segments of the same limb.

Question 25

What are the stages of the injury process?

Answer 25

1. Surveillance 2. Aetiology 3. Prevention 4. Evaluation.

Question 26

What is an injury mechanism?

Answer 26

The physical process causing tissue damage due to mechanical loading.

Question 27

What is overuse injury?

Answer 27

Injury caused by repetitive stress without adequate recovery.

Question 28

What are the types of mechanical loads that can cause injury?

Answer 28

Compression, tension, shear, torsion, and bending.

Question 29

What is mechanical load?

Answer 29

Forces or stresses applied to a structure that can cause deformation.

Question 30

What is structural vulnerability?

Answer 30

A predisposition to injury due to weaknesses in body structure.

Question 31

What is the rationale for the study?

Answer 31

The study aims to investigate how arm swing affects joint kinetics and vertical jump performance. While arm swing is known to improve jump height (Lees et al., 2004; Mosier et al., 2017), the joint-specific contributions and coordination mechanisms are not fully understood. This research clarifies these biomechanical processes.

Question 32

What are the strengths of the VICON motion capture system?

Answer 32

High accuracy in capturing 3D motion data. Provides detailed kinematic and kinetic analysis. Useful for analyzing complex movements in real-time. Supports integration with force plates for comprehensive biomechanical analysis.

Question 33

What are the weaknesses of the VICON motion capture system?

Answer 33

High cost and complex setup. Limited to controlled lab environments. Marker occlusion can lead to data gaps. Requires expertise for accurate data processing and analysis.

Question 34

Why was Inverse Dynamics Analysis (IDA) used rather than Quasi-Static Analysis (QSA)?

Answer 34

IDA allows for the analysis of dynamic movements, accounting for joint accelerations and forces over time. QSA, which assumes no acceleration, is suitable for static or slow movements and would not capture the dynamic forces during a jump.

Question 35

What are the implications of the findings for practice and future research?

Answer 35

Practice: Coaches can optimize jump performance by incorporating specific arm swing techniques. Research: Future studies should explore arm swing variability, fatigue, and directionality to refine performance strategies further.

Question 36

Compare and contrast the differing approaches to the development of Body Segment Inertial Parameters (BSIP) and their use in sports biomechanics.

Answer 36

Cadaver-Based Models: Provide high accuracy but lack real-world applicability. Imaging Methods (e.g., MRI/CT): Offer individualized data but are costly. Anthropometric Tables: Quick and practical but generalized. BSIPs are essential for accurate biomechanical modeling in applied sports settings.

Question 37

Why do we need to filter kinematic data in sports biomechanics, and what is one method used?

Answer 37

Filtering reduces noise from data collection. The Butterworth Filter is a common method; it applies a low-pass filter to remove high-frequency noise while preserving the integrity of the signal. However, improper filtering can distort the data.

Question 38

How can variability be used to understand sport performance using motor control concepts?

Answer 38

Variability allows athletes to adapt to different conditions. For example, in a basketball jump shot, slight variations in movement patterns help optimize accuracy under different defensive pressures, enhancing performance flexibility and robustness.

Question 39

Explain the process of creating a free body diagram to calculate ankle joint moment.

Answer 39

Draw the Diagram: Represent the foot and leg, showing forces (e.g., ground reaction force) and joint locations. Identify Forces: Include body weight, ground reaction forces, and muscle forces. Write Equations: Use ∑ M = 0 ∑M=0 to balance moments. Calculate Joint Moment: Solve for the ankle joint moment using known forces and distances (moment arms).

Question 40

When does an injury occur

Answer 40

An injury occurs when mechanical stress exceeds the tissue’s capacity to absorb it, leading to structural or functional damage