Internal Joint Forces: ACL and Instability

Question 1

What do ACL, PCL, LCL and MCL stand for?

Answer 1

Anterior cruciate ligament (70% injuries caused by non-contact)

Posterior cruciate ligament

Lateral collateral ligament

Medial collateral ligament

Question 2

Four ways an ACL injury may be prevent by altering the biomechanics of an athlete’s movements

Answer 2

1. Reducing frontal plane knee joint angles
2. Reducing frontal plane knee loading
3. Increasing sagittal plane knee joint angles
4. Reducing sagittal plane knee loading

Question 3

How do you measure the Q-angle?

Answer 3

Line drawn from the ASIS to central patella and a second linedrawn from central patella to tibial tubercle

Question 4

What is increased Q-angle a risk for?

Answer 4

A risk factor for patellar subluxation (dislocation)

Question 5

What is a normal Q-angle in males and females?

Answer 5

14 degrees for males

17 degrees for females

Question 6

Double leg sagittal plane jump landing tasks may not adequately represent single-leg lower extremity biomechanics. Why not?

Answer 6

Familiarity to single-leg version

The neural demands are different

Demands across joints differ

Question 7

Knee valgus motion causes what to occur at the hip during a single leg drop jump?

Answer 7

Adduction and internal rotation at the hip, significantly greater with > knee valgus motion

Question 8

Watch lecture recording

Answer 8

16: 52 - 31:09
32: 49 - 55:06

Question 9

Why are drop pr depth jumping commonly selected by research studies?

Answer 9

Due to the high perceived intensity than other activities

Question 10

What key mechanical/kinetic variables are measured during a drop jump?

Answer 10

1. Impact Loading rate 10-90%
2. Peak impact force
3. Average impact force
4. Peak propulsive force

Question 11

What limitations to dynamic instability training may a researcher face?

Answer 11

Little consideration to adaptation

No familiarity to unique demands

Subsequent effects (stable surface)

Question 12

What considerations to dynamic instability training may a researcher have?

Answer 12

Reflect a real-world training programme

Thorough analysis to understand underlying mechanical and neuromuscular mechanisms

Multi-variable approach (>250)

Question 13

High internal hip & knee abduction torques are believed to result in what?

Answer 13

ACL injuries

Question 14

What is a valid indicator of potential risk of an ACL injury?

Answer 14

Drop jumps and single legged hop

Question 15

What three types of strength training is needed to reduce risk of ACL injury?

Answer 15

Hip & knee flexion strength training

Adduction and Abduction Extension strength training

(As well as increasing movement variability within training sessions may also help reduce the chance of theses types of injury’s)

Question 16

Surface instability requires ** ** ** and *** of the subsequent effects when *** **** is ***

Answer 16

Surface instability requires more robust design and investigation of the subsequent effects when instability stimulus is removed