The hamstrings need to be 60-70% in strength compared to the quads to help prevent muscle imbalances that will lead to injury
Neuromuscular control and Balance
Flexibility
Gradual stretching
Dynamic and Static stretching for warm ups and cool downs
Cardiovascular and Muscular Endurance
Agility and Speed
Specific Skill Development
Rehabilitation
Injured knees need to be properly rehabilitated before return to play
Knee is more prone to major injuries after a minor injury
Shoe Type
Wear correct cleats.
Don't wear soccer cleats if you play football
Have correct insoles or orthotics if anatomical deviation/ abnormality
Don't have a game cleat and a practice cleat
Consistency
Break in shoes gradually
Bracing
Knee braces are widely debated
Effectiveness of protective knee braces are controversial
Merely reduce severity but not prevent
Prophylactic knee braces can reduce the severity of injury
Functional knee braces can help protect ACL sprains
Custom fitted braces will be the best at protection and reduction from injury
Also more expensive than off the shelf
Image copied from http://media.summitmedicalgroup.com/media/db/relayhealth-images/xsttrnlb_2.jpg
Image copied from http://www.breg.com/products/knee-bracing/functional-ligament/fusion-knee-brace
We do not advertise for Breg but are merely using their brace as an example