This study looks at the effects of blood flow restriction training (BFRT) for teenagers (ages 12-18) who had surgery to fix their anterior cruciate ligament (ACL). The ACL is a ligament in the knee that helps keep it stable. After surgery, some people have weak quadriceps muscles. Quadriceps are the muscles on the front of your thighs. The study will see if BFRT, a type of exercise that uses a band to slow blood flow, can help these muscles get stronger and if it improves life quality. Participants will be split into two groups: one will do BFRT, and the other will follow regular therapy. Therapy sessions happen twice a week for 16 weeks.

• **Study Duration**: 16 weeks with 2 visits each week.
• **Compensation**: Not mentioned.
• **Risks**: Possible skin irritation and discomfort from the band.