Practical Review of Knee Injury Prevention Exercise for Young Athletes

Practical Review of Knee Injury Prevention Exercise for Young Athletes

mag. Stef Harley, univ. dipl. FTH

Ali Nassib, dipl. FTH

Maj 2014, ZVD Center za medicino športa, Ljubljana

Strokovni posvet: KAKO DO ZDRAVEGA ŠPORTNIKA V ZRELIH LETIH? Preprečevanje in uspešno zdravljenje poškodb kolena

Knee Injuries in Young Athletes

• 63% sports injuries are joint sprains

• Majority occur in knee

• ACL injuries most common in all ages

• Highest incidence in pivoting sports; ≤ 3.7/1,000h

• Women at 6x higher risk

Prevention is High Priority

ACL injury may lead to:• Concomittent meniscus and cartilage damage• Acute & chronic muscle deconditioning• Knee instability unavoidable

• Future career questionable !

• 5% population with OA have knee injury history

• 50% develop OA ≥10years• 41% more recovery time

Injury mechanisms• 70-84% non-contact situation

• Landing, cutting, decelaration & changes in direction High knee internal extension torque Dynamic valgus rotation BW over injured leg Plantar surface of foot fixed

• Inability to adequately absord GRF

Risk factors & prevention

• External and internal; environmental, anatomical, hormonal , neuromuscular and biomechanical conditions

• Modifiable and non-modifiable

• Prevention strategy: In-depth analysis external &

internal RF Modifiable or non-modifiable? Modify RF through target training

intervention Understand impact non-

modifiable RF

Landing strategy & posture• Increase GRF dampening capabilities

• Increase plantar flexion• Reduce hip flexion• Control knee valgus• Control Q/H power ratios• Stimulate hamstring reflex arc

• Athletes physical capabilities?

CORE stability• Uncontrolled hip ADD and IR with knee ABD

increases risk

• Adolescent athletes; decreased hip & trunk stability Hip and trunk weakness; Excessive movement in frontal and transverse planes; Leads to LE valgus loading

• Strenghtening• Hip ER and ABD• Trunk stabilizers

• High peak force development• Plyometrics – increases efficacy stretch–shortening cycle• Stimulate feed-forward mechanisms - proper technique

Hamstring activation

• Increased HS flexibility slows muscle activation;

• Greater delay in Q/H co-contraction;

• Less functional knee stability;

• HS activation exercises increase functional stability

ACL injury prevention programs• No consensus• Clear progressions• Adressing multiple components yields better results

Decreasing GRF Decreasing varus/valgus moments Increase muscle activation and strength in CORE, hip and

trunk Train feed-forward mechanisms; awareness and in-game

decision making Plyometrics Pre-season combined with in-season maintenance

• Duration, pre-season; 6-8 weeks, 2-3/week• Fatigue?• Compliance?

Common Components

• Proper landing technique

• Engaging knee and hip flexion during landing and lateral movement

• Avoid excessive knee valgus during landing

• Increase HS, hip ER and ABD strength and activation

• Proper deceleration techniques

• Agility skills

• Dynamic balance training

Proper landing technique

Knee & hip flexion during landing

Avoiding knee valgus

HS, hip ER & ABD strength and activation

Deceleration and agility

Wilderman DR, Ross SE, Padua DA. Thight muscle activity, knee motion, and impact force during side-step pivoting in agility-trained female basketball players. Journal of Athletic Training 2009;44(1):14-25

Dynamic balance

Conclusions

• Preventing ACL injury in young athletes makes sense

• Structured preventive exercise has positive effect

• Know and understand risk factors for the target group

• Build compliance – get everyone involved; use performance measures

• Pre-season and maintenance