Sport Biomechanics Introduction

Question 1

What are the 3 roles of studying biomechanics in the injury -> rehab->train-> injury loop

Answer 1

1) Provide methods of prevention to musculoskeletal injuries
2) Provide quantitative and objective assessments to evaluate the result of the treatment method
3) Provide an objective way of monitoring long term rehabilitation progress, to determine if recovery has been successful

Question 2

What is the sequence of injury prevention research?

Answer 2

basically:
1. What is the problem
2. Who, why and What caused the problem
3. How could we prevent the problem
4. Validation (Does the preventative method solve the original problem) by repeating step 1 while employing it

Question 3

The the sequence of injury prevention analysis, what is the biomechanics assessment and its aims.

Answer 3

to evaluate the effectiveness of preventative measures:
aims to evaluate:
1. That the risk factors are suppressed
2. Whether the aetiology (cause) is eliminated
3. The mechanism of injury is prohibited

Question 4

In the sequence of injury prevention model, if the assessed preventative measure are found to be biomechanically effective, what happens next?

Answer 4

• An epidemiology study can be conducted to evaluate if the ultimate effect on the rate on injury incidence when employing the new preventative method
• If the injury incidence rate is significantly reduced, the preventative measures are assessed as ‘clinically effective’

Question 5

When discussing sports injuries, risk factors are either intrinsic or extrinsic, what does this mean?

Answer 5

Intrinsic risk: caused by poor biomechanics, poor training and conditioning, maturational changes, somatotype(body type)
Extrinsic risk: weather, field conditions, rules and equipment

Question 6

Give an example of a not changeable risk factor?

Answer 6

Women are more predisposed to ACL injuries during preovulatory phase of menstruation
Players with previous sprain injuries are at a higher risk of repeat sprains

Question 7

List some preventable risk factors to sport injury:

Answer 7

Not stretching, wearing soft and high shoes for lifting

Question 8

Give an example of an aetiology test? A test to if a factor contributes to the cause of an injury

Answer 8

• Changing a subjects arm positioning when doing a change of direction cutting movement.
• Or changing the landing surface angle to see if that could be a contributor to injury rate

Question 9

What was the first biomechanics study of a sport injury mechanism. And what did they calculate

Answer 9

• 1977, Zernicke
• Injury mechanism: Patellar tendon rupture during weight lifting competition
• They derived a formula to calculate the load put through the patella tendon before and during rupture
• Finding max knee moment (550Nm) and the tendon tension strength (14.5kN)

Question 10

How have injury mechanisms causing knee injuries been measured through video footage?

Answer 10

Dr Krosshaug, developed Model Based Image Matching (MBIM) motion analysis
- This uses footage to gather information like joint angles, ground reaction forces, speed, joint loading and torque

Question 11

How and what are the limitations to conducting In-vivo strain measurements tests?

Answer 11

Tiny Strain Gauges can be sewn into ligaments such as the ACL to measure strain levels through that ligament

Limitations: This requires surgery and anaesthesia, difficult to perform, get ethical approval and find volunteers

Question 12

What are the types of strain gauges that have been used for this

Answer 12

• DVRT
• Liquid Mercury strain gauge
• Hall effect strain transducer

Question 13

How can we ethically measure ligament and muscular limitations?
(There are 2)

Answer 13

Using Cadavers
A machine called a universal force motion sensor (UFS) has been used to study knee biomechanics
- stresses are applies until breaking then compared to ligaments with cuts/ruptures

Mathematical modelling on humans
Finite element Analysis to observe regional loads in human biomechanics in combo with motion capture

Question 14

What is a downfall of using MBIM? (Model Based Image Matching motion analysis) (anaylsing videos)

Answer 14

Large scale MBIM analysis is not cost effective and further testing on injury prevention methods is not possible

Question 15

What is the purpose of a close to injury situation experiment

Answer 15

Putting the body into ‘close to injury situations’ provides information about an injury mechanism, how the body reacts and also how they could be prevented

Question 16

Give an example of a close to injury situation

Answer 16

Dropping off a box onto an inclined plane
Dropping off a box and changing direction

Question 17

Explain how hight top shoes are a manifestation of biomechanics

Answer 17

Biomechanics contribute to the design of preventative measures
- The mechanism of sport related ankle injuries was identified as landing with an inverted and plantarflexed ankle with ankle inversion.
- High top shoes prevent this by stopping this ankle orientation

Question 18

Describe 2 other preventative measure designs used today?

Answer 18

1) Knee braces to reinforce weak knees against shear forces causing ACL rupture
2) Sliding soft ball bases, to reduce the risk of injuries caused by sliding and hitting a solid base

Question 19

How does the intelligent anti-sprain sport shoe operate?

Answer 19

• Muscles are too slow to respond to ankle sprain motion
• Anti sprain shoes have a 3 step mechanism built to sense, identify and then make a correction if supination passes a limit of safety.
• If the shoe sense a hazardous level of foot supination, in initiates the peroneal muscles in the foot to contract, pulling the foot back to neutral

Question 20

What is the logical step taken after a preventative measure is designed?

Answer 20

conduct an epidemiology test, to assess whether this preventative design reduced the rate of injury incidence.

Question 21

What are the 5 main biomechanic tools/measures used to evaluate the outcome of treatment in sport?

Answer 21

look at:
1) Muscle activity and function
2) Joint loads, torque and kinetics
3) motion and kinematics
4) Proprioception
5) Sports Performance

Question 22

Explain how Muscle ratios, and knee orientation in the frontal plane might effect injury

Answer 22

• It has been found that a low Hamstring : Quadracep, ratio is a key risk factor of ACL injury
• Women have naturally more valgus knees, which is a risk factor of ACL injuries when landing

Question 23

How have motion capture and kinematics been used as a tool for assessing biomechanics?

Answer 23

• Motion capture, to analyse gait symmetry of a patient with prescription orthotics to assess the effect
• Marker pins on intra cortical bones have been used to study bone motion during movement

Question 24

What methods do we have to assess angle of joins during operative treatment?

Answer 24

• Electromagnetic trackers and navigation systems have been used to measure joint angle during operation