1. Pre-surgical phase (Phase 1)

2. Before surgery, the patient must reach these goals 1- Control of pain and swelling with rest, cryotherapy (ice bags for 20 min three times a day), NSAID, and dressing (not during exercises) 2- Recovery of full ROM with passive and active knee extension in supine position with the heel raised slightly (Fig.1), passive knee extension in prone position with the leg out of the bed and the knees on the edge, active knee extension with the heel on an inclined plane (Fig. 2), and active knee flexion in supine position on a slide board (Fig.3) or performing wall slides (Fig. 4). (Another way to perform active knee flexion is in the sitting position). 3- Reestablishment of normal gait by walking with crutches (partial weight bearing also using a mirror to note mistakes) and the knee in full extension during weight bearing and flexed during the swing phase of the gait 4- The patient must also regain muscle strength (quadriceps and hamstrings).

5. The goals of rehabilitation after ACL reconstruction 1- joint stability (protection of the healing graft) 2- full ROM (including extension at levels of the uninvolved side), 3- muscle strength (both concentric and eccentric), 4- proprioception, 5- improve cardiovascular endurance 6- preinjury levels of activity.

6. Phase 2: First and Second Postoperative Weeks GOALS 1- wound healing 2- reduce swelling and pain 3- regain full extension 4- regain 90°- 110° flexion 5- Initiate muscle control 6- gradual weight bearing

7. Phase 2: First and Second Postoperative Weeks 1- Cryotherapy: ice bag on the knee (20 min six times a day). 2- Active foot flexion-extension (ankle pump" exercise 5-min every half hour). 3- Full knee extension : passive knee extension with heel on a support such as a rolled towel 5-10min every hour (Fig.1), active knee extension with the heel on an inclined plane performing quadriceps contraction to low the knee toward the bed surface (Fig. 2). 4- Static quadriceps contractions: relearn how to contract the quadriceps 5 min/h (Fig.3), straight leg raises with the knee fully extended without extension lag (10-min session of raising the limb 20 cm slowly, holding the contraction for 6 s, and then resting for 5 s) four to five times a day (Fig. 4).

10. Phase 2: First and Second Postoperative Weeks 5- Knee flexion: active knee flexion sliding on a board (10 min every 2h up to 90 0 during the first week) (Fig.5). To achieve 100°- 110° knee flexion, the exercises can also be performed while sitting with the leg out of the bed or in supine position sliding down with the foot leaning on a wall (wall slides) (Fig. 6). 6- Gait: partial weight bearing with two crutches is allowed from the first postoperative day to visit the bathroom, then gradually increased as tolerated with 50%, the patient must maintain full knee extension and achieve at least 100 0 -110 0 of knee flexion. 7- At the end of every exercise session, 20min of cryotherapy must be performed. 8- EMS: it is possible to perform electrical quadriceps stimulation maintaining the knee in full extension and to relief pain. 9- Warning: to prevent loss of extension, the patient must not place supports under the knee.

12. Phase 3: Third and Fourth Postoperative Weeks GOALS 1- Increase active range of motion 2- Develop muscular control of quadriceps and hamstring 3- Increase weight bearing during gait 4- Improve cardiovascular endurance

13. Phase 3: Third and Fourth Postoperative Weeks If there is lack of extension, a new exercise is added to the protocol: passive knee extension in prone position with the leg out of the bed and a light weight (0.5 – 1 kg) on the heel for 15 min three times a day (Fig. 7). The best way to check extension is to observe heel height during the exercise. Patellar mobilization must be done with the knee in full extension (5 min three times a day). Muscle exercises: 1- Straight leg raises with weight on the thigh (Fig. 8) (20 repetitions holding the contraction for 8 s four times a day). 2- Two-legged minisquat with up to 45 0 of knee flexion using crutches (ten repetitions slowly two to three times a day) (Fig. 9). 3- Active extension 90 0 to 45 0 (stopping at 45 0 ) without resistance while sitting (Fig. 10) 4- Active knee flexion in standing position.

18. Phase 3: Third and Fourth Postoperative Weeks 5- Active assisted flexion (more than 120 0 ) in sitting position 6- Cocontraction: simultaneous isometric (60°) contractions of quadriceps and hamstrings muscles. 7- Gait, increase weight bearing gradually as tolerated with one crutch. It can be useful walk in front of a mirror trying to achieve full knee extension in the weight-bearing phase and flexion during the swing phase of the gait 8- Swimming pool. From the end of the third week, it is possible to perform the following water exercises: walking forward and backward, straight leg raises, adductor/abductor/flexor exercises, aqua jogging with a flotation life jacket,, and bicycling simulation with a life jacket (Fig. 11). 9- Stationary bicycle for 10 min two to three times a day slowly, without wheel resistance, and pedaling with the forefoot (Fig. 12)

20. Phase 4: Second Postoperative Month Goals 1- Restore full ROM 2- Improve muscle strength 3- Full weight bearing

21. Phase 4: Second Postoperative Month 1- In comparison with the contralateral knee, if extension lag obtained. If necessary, the patient continues stretching exercises and can apply a hyperextension device during the night. 2- Flexion must be more than 120 0 and gradually reach the contralateral level (full ROM). 3- Gait the patient can walk without crutches and gradually returns to activities of daily living and light work. Climbing and descending stairs is forbidden until the end of the second postoperative month. 4- Stationary bicycle; 15 min three times a day with low wheel resistance (50 W) simulating a slow -ride on level road, pedaling with the forefoot.

22. Phase 4: Second Postoperative Month 5- Muscle strengthening exercises with elastic tubing are useful because they allow gradual resistance: a)- leg press stopping at 45 0 (Fig. 13), b)- knee flexion while sitting with the plantar surface of the foot sliding on the floor (Fig. 14), c)- half squat in the 45°-90° ROM (Fig. 15), d)- "duck walk" with the knee flexed and the trunk bent forward (Fig. 16), e)- hip muscle (adductors, abductors, flexors, extensors) strengthening exercises first without and later with elastic resistance. 6- Exercises to be performed in the swimming pool are: walking into the deep water, straight leg raises, adduction and abduction, frontal and lateral climbing and descending stairs, underwater stationary bicycle, and aqua jogging with a life jacket.

25. Phase 5: Third Postoperative Month Goals 1- full active ROM 2- Increasing muscle strength 3- Proprioceptive training

26. Phase 5: Third Postoperative Month 1- eccentric quadriceps strengthening exercises like two-legged squatting up to 90 0 (on land and in a swimming pool), 2- climbing and descending stairs into the water (20-40 cm, gradually increasing), 3- concentric quadriceps strengthening exercises (active full knee extension-flexion without resistance)

27. Phase 5: Third Postoperative Month 4- one-legged proprioceptive exercises on unstable surfaces (5 min three to four times a day) for balance and coordination to regain dynamic control of the knee joint, first on a simple board with only one axis of instability (flexion-extension or pronation-supination of the foot) and then with instability in all axes (hemispherical base) with the knee flexed at 30 0 (Fig. 16). The patient starts proprioceptive exercises in sitting position, then with the hands against a wall, and then balancing on one leg. 5- Jumping on springboards is useful for enhancing proprioception without overloading the knee joint patient 6- Bicycling can be started for brief periods (10-15 mm) on a level road. 7- Jogging is allowed on a straight course for 10 min/day.

30. Multidirectional rolling movement

31. Single leg stand on balance board

32. Phase 5: Third Postoperative Month Attending a gym, it is possible to use some devices: 1- Rowing simulator (Fig. 17) to be performed with erect spine, flexing first the leg and then the arm for 10 - 20 min after a good muscle warm up 2- Horizontal leg press (Fig. 18) for 10 - 20 min, cautiously with a resistance of 5-10 kg and after a good muscle warm up 3- Slide board (Fig. 19), sliding alternately on the left and on the right 4- Step machine or stair climbing simulator, to be performed cautiously and briefly with low loads (Fig. 20).

35. Phase 6: Fourth Postoperative Month Goals 1-Increase leg strength 2-Advanced proprioception

36. Phase 6: Fourth Postoperative Month 1- jogging time and distance may be increased, adding change of direction (drawing "o" and "8" figures) and 2- uphill and downhill. 3- Bicycling is possible with increased distance and also uphill and downhill. 4- The swimming pool should be attended, performing freestyle and jumping into the water. 5- Proprioceptive exercises are continued. 6- Concentric quadriceps strengthening must be performed (active full knee extension-flexion with or without resistance applied below the patella but not on the ankle). Isokinetic training at an angular speed of 180°/s can be useful

37. "Kickers" use an elastic band fixed to the distal aspect of the involved or uninvolved limb. The athlete attempts to balance while executing short kicks with either knee extension or hip flexion. This exercise is most difficult when performed on unstable surfaces.

39. Fifth postoperative month Goals functional training (prepare for return to sport and recreational lifestyle )

40. Fifth postoperative month 1-The patient can practice running with acceleration, deceleration, and "stop and go" 2- return to sport-specific activities can begin including normal running, jumping, cutting, double and single hopping, vertical jumping.

43. Plyometrics begin with low-impact hopping, progressing to double-leg bounding, and finally single-leg hopping.

44. Sixth post­operative month Goal Return to activity safely

45. Sixth post­operative month Return to sports 1-Full training for 1 month prior to active return to competitive sport 2-Preparation for body contact sports. Begin with low intensity one on one contests and progress by increasing intensity and complexity in preparation for drills that one might be expected to do at training

47. Criteria for return 1- No joint effusion 2- Full ROM 3- isokinetic testing indicates that strength of hamstring and quadriceps is 85- 100° of the uninvolved leg 4- Satisfactory ligament stability testing using KT 1000 arthrometer 5- Successful performance during functional testing