biomechanics of injury and injury prevention Flashcards
List the three stages in the biomechanical reduction of injury process.
- Description of incidence and types of injury
- Identification of factors and mechanisms of injuries
- Prevention and reduction of risk
Describe the process involved in stage 1 – Description of incidence and types of injury
This stage involves identification of injuries
- Statistics on injury rates and types
- Analysis of Single / individual injury
Describe the process involved in stage 2 – Identification of factors and mechanisms of injury
This stage involves
- Properties of biological materials (estimation of forces) - how tissue performs under pressure
- Mechanisms of injury occurrence
Complete this sentence: Injury occurs when ….
Injury occurs when ….loads exceed tissue failure tolerance
There are six main contributory factors that injury occurrence and type in sport / exercise / work
depend upon. List, explain and provide examples for each of these six factors.
Load characteristics
- Type (tension, compression etc)
- Magnitude
- Load rate
- Frequency of load repetition
Characteristic of loaded tissue
- Material properties of bone & soft tissues
- Structure properties of bone, joint & soft tissue
Genetic factors
- Innate musculoskeletal deformities
- Age, sex
Fitness or training status
- Lack of flexibility or joint laxity
- Muscle strength imbalances
- Incorrect body weight
- Excessive training load for fitness state
- Over-training, fatigue
Technique
- Poor technique causing excessive load
- Illegal technique (shoulder charges NRL)
Equipment and surfaces
- Human surface interface
- Human and equipment interface
The prevention and reduction of risk stage involves the application of knowledge obtained from
the earlier stages and can result in what? Provide at least one example for each.
Rule changes
- Ruckman - reduce length of run up to prevent posterior cruciate lig injury)
Equipment modification
- Mouth guards
Technique modification
- Scrum - count to three
Physiological adaptation
- Conditioned to withstand load)
The type of surface and properties of these surfaces greatly influence injury risk and rates. List and
explain how 5 different surface properties can influence injury rates.
Friction and taction
- Too high or too low
Compliance
- Amount of deformation under load
- Too high and too low
Rebound (resilience)
- Measure of energy absorbed by the surface that is returned to the striking object
- Lack of resilience causes fatigue
Hardness
- The resistance of a materials surface layer to penetration
Force reduction
- Expresses the % reduction of max force experienced on a surface compared to concrete
- Impact attenuation
- IAAF specifies force reduction between 35 & 50%
- Atlanta track 36%
How might a surface that is too hard affect injury rates?
- Increase impact loading
- Peak force, time to peak, RFD
- Implicated with cartilage and bone damage (shin splints)
- Increased incidence of tendon and calf injuries
- Worst for lower limb and back injury
- Klauss (1982)
- Bone micro-fractures, pain and reduction in shock-absorbency, increased reliance on cartilage
Describe how uphill and downhill running can increase the risk of injury
Uphill
- Increased stress on patellar ligament and quadriceps tendon
- Increased stress on ankle plantar flexors
- Forward pelvic tilt and limited hip flexion increases stress on muscles of lumbar spine
Downhill
- Increased stride length results in > heel strike impact forces
- Greater eccentric loading → muscle damage
- Increased compressive force between patella and femur → patella femoral pain
Running shoes have been shown to affect injury rates in runners. Comment on the aspects of
friction, impact and rear foot motion control in relation to running shoes
Friction
- Too much friction
- Insufficient rotational freedom between shoe and surface
- Foot becomes fixed and body rotates (knee Injuries)
- Too little friction
- Slipping → loss of balance → muscle tears
Impact
- Basic injury risk in running is impact
- Peak impact force
- Max RFD
- Time to peak impact force
- Time to reach max RFD
- Peak impact force > in rear-foot strikers
Rear foot motion
- Rear foot control is the ability to limit the amount and rate of pronation immediately after foot strike
- Pronation is normal, aids dissipation of force
- Over pronation
- Causes increased medial rotation of tibia
- Linked with a wide range of injuries
- Can be caused by inappropriate heel flare
- Straight last helps reduce pronation
