What Is an ACL Injury? How It Happens and the Role of Physical Therapy in Recovery
Understanding the ACL
The anterior cruciate ligament (ACL) is one of the key stabilizing ligaments in the knee. It runs diagonally through the middle of the joint, keeping the shin bone (tibia) from sliding forward on the thigh bone (femur) and providing rotational stability.
How ACL Injuries Happen
ACL tears are common in athletes who play sports that involve cutting, pivoting, or sudden stops—such as soccer, basketball, football, and skiing.
Typical causes include:
Sudden direction change or pivot on a planted foot
Landing awkwardly from a jump
Direct impact to the knee in contact sports
Overextension of the knee
Many ACL injuries are non-contact—happening without a collision, often when an athlete’s mechanics or strength can’t meet the demand of the movement.
Symptoms of an ACL Tear
A “pop” at the time of injury
Immediate swelling in the knee
Instability or the feeling the knee may “give out”
Pain and difficulty bearing weight
Treatment Options
Non-surgical: Some partial tears or lower-demand patients can recover with bracing, strengthening, and physical therapy.
Surgical reconstruction: Many athletes with complete tears undergo surgery to restore stability, especially if they want to return to cutting and pivoting sports.
The Role of Physical Therapy in ACL Rehab
Whether an athlete chooses surgery or non-surgical management, physical therapy is critical:
Pre-surgery (“prehab”)
Reduce swelling and restore motion
Strengthen muscles to improve post-op recovery
Post-surgery rehab
Regain range of motion safely
Rebuild quadriceps, hamstring, and hip strength
Retrain balance, coordination, and agility
Progressive return-to-sport training, including jumping, cutting, and sprinting
Prevention of reinjury
Correct faulty mechanics (landing, pivoting)
Develop single-leg control and strength
Teach proper sport-specific movement strategies
Return to Sport Timeline & Re-Injury Risk
On average, athletes return to sport around 9–12 months after ACL reconstruction when following a structured rehab program. Every recovery is unique—factors such as graft type, sport demands, and consistency with rehab all influence the timeline.
Re-injury risk is also a major consideration: research shows that 20–30% of athletes sustain a second ACL tear, either in the same knee or the opposite one. The risk is highest in younger athletes and those who return to cutting and pivoting sports too soon. Structured physical therapy is essential not only for recovery but also for long-term knee protection.
Takeaway
An ACL injury is serious, but with proper treatment and structured physical therapy, most athletes can return to their sport. Early evaluation, a customized rehab plan, and consistent progressions are the keys to success.
📅 Next Step: If you’ve experienced a knee injury or want to reduce your risk of ACL tears, schedule an evaluation at SB Physio to get a plan tailored to your sport and goals.
Important Disclaimer
This blog is for educational purposes only and is not a substitute for personalized medical advice. ACL injuries should be evaluated by a licensed healthcare provider. Treatment and return-to-sport decisions should be made with the guidance of an orthopedic surgeon and physical therapist.
