Copenhagen ACL protocol – A criteria and time driven guideline for Anterior Cruciate Ligament rehabilitation in a clinical sitting.

Author: Andreas Bjerregaard, Physiotherapist and IOC Diploma in Physical Therapy

The introduction:

The aim of this guideline is to share some thoughts about what approach to take in rehabilitation and reconditioning for patients undergoing either conservative treatment or reconstruction of the Anterior Cruciate Ligament (ACL). The Copenhagen ACL rehabilitation protocol is a based by personal experience, and frustration trying to translate evidence based practice into clinical real life situation. I hope this guide can provide some inspiration for both health professional and patients.

Every ACL-patient is slightly different, but there are similarities in how we should progress the rehab.  Due to practical considerations, this guideline is both a criteria and time-driven guideline. It is using functional criteria for pregressen more than time frames, but in respect for swelling, wound healing, bone bruising, graft maturation and so on. In a real world cases, your patient has a estimated amount of treatment due to sick leave, insurance and so on.

Therefore, as a clinician, you already have to consider the exit strategy doing the first couple of treatment, so the patient don’t become an external harddriver to your rehab, where the minute you unplugged your patient, they can’t train on their own.

Previously data has shown that 63% of athletes returned to preinjury level, but only 44% returned to competitive sports, and ⅔ are not back at preinjury level at 12 months (1), and that athletes that did not meet return-to-play (RTP) criteria had a fourfold increased risk for re-ruptures (2). This highlights why an honest talk about expectation is crucial due to a common cognitive bias (optimistic bias) that causes a persons to believe that they are at a lesser risk of being a part of the statistic. However, simple decision rules can reduce re-injury risk by 84% after ACL reconstruction (3)

One of the big barriers for not returning to sports is fear for re-injury. A recent study (4) showed that athletes treated by a sports physical therapist had a 3.09 times higher chance of meeting the RTP criteria than those treated by a general or manual therapist. Therefore, the study recommend athletes to make a careful consideration when they choose their physical therapist.

This is inline with other rehabilitation area where therapist’s thoughts, beliefs and own fear can stand in the way of a successful outcome by adding nocebo, fear of movement and catastrophizing thinking.

The rehabilitation should be implemented in the biopsychosocial frame, where the focus is on a person with knee problem, and not a knee patient.

Reading this protocol

The Anterior Cruciate Ligament has often been compared to a car seat belt. We do not use the seatbelt while driving, but should we make a sudden change or a severe braking, then the seatbelt should work. In comparison, we do not use our ACL when we just walk around, which may be the argument for not reconstructing all ACL, however participating in sport that requires change of direction, pivoting and contact, it could be that our ACL would act as an a safety belt.

As you read through this Copenhagen ACL protocol, will you notice that the first couple of weeks will be more or one-size-fit all. This is due to development of fundamental movement skills that focus on quality of movement before quantity and can be based on principle of General Physical Preparedness (GPP). When we go through the protocol the rehabilitation should be more individualised based on testing, milestone and goal setting which i comparable to Specific Physical Preparedness (SPP).

When are writing the training programme, we have to make a programme that fits the patient, and be careful not trying to make the patient fit into rigid protocol. Scott, et. al. (5) pointed it when he concluded that unimodal rehabilitation interventions and generic prescriptions based solely on evidence based medicine are unlikely to be optimal in the rehabilitation of injuries, particularly in athletes.

Another piece to the puzzle is that we should be skeptical about is the 10% leg symmetric index (LSI) rule, as it can be easy fooled yourself, if 10% is reach due to decrease in performance from the “healthy” leg. In general, tests that are commonly used are not demanding enough or not sensitive enough to identify differences between injured and non-injured sides (6).

The ACL rehabilitation program

When deliver rehabilitation program, my experience is, the variations and graded exposure in exercise selection often correlates with a higher motivation and attendance. Some of the common training variables are volume, intensity, frequency, repetitions, set, load, speed, isometrics-, moderate-, heavy-, reactive-, explosive, strength, showed in absolute and maximal values. Further consideration could be SSC time, uni vs. two leg exercise. In addition NMES and BRF can be used to boost muscle activation and hypertrophy.


For me the three A’s, Attendance, adherence and adapt, is a good recipe for a good training programme. Our patient have to attend to the rehabilitation, they have to be consistent and stick to the plan. To optimize attendance and adherence objective and subjective feedback and data can boost any programme to make a more optimised adaptation.  

Take home message before you start.

The take home when trying to optimise your protocol is that the difficulty do not lies so much in developing new ideas as in escaping from old ones.

A good sports physiotherapist capable to adjust the exercises individual into the different stages of rehab.
Key abbreviations

  • DB = Dumbbell
  • KB = Kettlebell
  • BB = Barbell
  • BW = Bodyweight

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  1. Ardern, C.L, et al. Fifty-five per cent return to competitive sport following anterior cruciate ligament reconstruction surgery: an updated systematic review and meta-analysis including aspects of physical functioning and contextual factors, Br J Sports Med. 2014
  2. Kyritsis, P, Bahr R, Landreau P, Miladi R, Witvrouw E. Likelihood of ACL graft rupture: not meeting six clinical discharge criteria before return to sport is associated with a four times greater risk of rupture. Br J Sports Med 2016;50(15):946-51
  3. Grindem H, Snyder-Mackler L, Moksnes H, et al, Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study, Br J Sports Med 2016;50:804-808.
  4. Melick, N.V, Only 19% of pivoting athletes after anterior cruciate ligament reconstruction meets return-to-play (RTP) criteria when their physical therapist releases them to RTP, November 2017Volume 28, Pages e20–e21
  5. Scott A, Docking S, Vicenzino B, et al Sports and exercise-related tendinopathies: a review of selected topical issues by participants of the second International Scientific Tendinopathy Symposium (ISTS) Vancouver 2012 Br J Sports Med 2013;47:536-544.
  6. Thomeé R, Kaplan Y, Kvist J, et al. Muscle strength and hop performance criteria prior to return to sports after ACL reconstruction. Knee Surg Sports Traumatol Arthrosc. 2011;19:1798-1805


Protocol suggestion from evidence and clinical experience Goal
Rehabilitation before surgery, termed “preoperative rehabilitation”. This phase can be used to educate the patient regarding exercise selection after surgery. Some litteraturer suggesting that the good pre-op training can predict knee function after the rehabilitation. Here is some suggestions for testing before surgery.

  • Biodex 20% quadriceps decifit (1)
  • 6-m timed hop test > 88% (Reference)
  • The International Knee Documentation Committee Subjective Knee Form IKDC2000, KOOS. RSI-ACL
  • Star Excursion Balance Test (SEBT test).
  • Number of single leg squat for 90 degree bench.

Pre-Season test

  • Nordbord
  • T-test
  • Squeeze test
  • Sprinting times: 10m, 30m and 40m sprint.


1) Eitzen, Preoperative quadriceps strength is a significant predictor of knee function two years after anterior cruciate ligament reconstruction, 2009 Br J Sports Med.
2) Logerstedt et. al., Single-legged hop tests as predictors of self-reported knee function after anterior cruciate ligament reconstruction: the Delaware-Oslo ACL cohort study, 2012 Am J Sports Med.
3) Alshewaier S. et al., The effectiveness of pre-operFull ative exercise physiotherapy rehabilitation on the outcomes of treatment following anterior cruciate ligament injury: A systematic review, 2016,. Clin Rehabil
4) Logerstedt et al., Does Extended Preoperative Rehabilitation Influence Outcomes 2 Years After ACL Reconstruction? 2016, Am J Sports Med.

Phase: Pre surgery / pre-op / pre-rehabilitation
The goal for the pr-op is to go hard to hit the numbers

  • 10-20% quadriceps decifit (1)
  • Get full extension

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0-2 wks post: Work on ekstension, swelling and m. quadriceps firing and balance.
Exercise suggestions

Mobility: Slides Seated Active Assisted Knee Flexion, SLR (alt), Flexion, Hamstring (L-drive), standing terminal knee ekstension (TKE)

Strength Adduction, Abduction lift, Calf raises, theraband isometrics, BW-air-squat ,static wall squat (evt. using a pilatesball), glute lift, clambshell, single leg squat

Balance / sensorimotor training(Open eyes rotate + vertical, Close eyes rotatio + vertical  1 or 2 legs, Wooble board

Other training Ankle Pumps, Gait Training (with and without cutches), (theraband perturbation)

Other modalities

  • High Intensity NMES (Neuromuscular Electrical Stimulation)

Ref: Kim et. al., Effects of neuromuscular electrical stimulation after anterior cruciate ligament reconstruction on quadriceps strength, function, and patient-oriented outcomes: a systematic review, J Orthop Sports Phys Ther. 2010

  • Blood Flow restriction using the 30 – 15 – 15 – 15 protocol and total occlusion time for 10 minutes.

Example of superset

  • Ankle joint movement, pumps
  • Quadriceps contraction
    •    15 maximal contractions, 6 s. each
    •    10 sub max contraction with contraction each second.
  • 10 SLR
  • 10 maximal hamstring contractions
  • Abductor in side position / clambshell
  • This program was repeated during 10 min period in each hour

(Eitzen, et al. A Progressive 5-Week Exercise Therapy Program Leads to Significant Improvement in Knee Function Early After Anterior Cruciate Ligament Injury, J Orthop Sports Phys Ther 2011)


  • Initiate Muscle activation and minimise muscle atrophy
  • improve ROM
  • eliminate swelling.
  • Milestone remove the wounds after around two weeks
  • Pain education
  • When the patient can perform a SLR he can leave the crutches.
  • Use POLICE
  • 24/7 perspective – awareness of total load

Objective measurement


Aim 2-6 wks. Continue aims from previously phase. Focus on knee control in weight bearing function.

Establish home exercise routines (Old school papers or google sheet/docs can be usefull), introduce cardio training and eventuel referral to hydrotherapy.
Exercise suggestions

Mobility: Slides Seated Active Assisted Knee Flexion, SLR (alt), Flexion, Hamstring (L-drive), standing terminal knee ekstension (TKE)

Strength Adduction, Abduction lift, Calf raises, theraband isometrics, BW-air-squat, static squat (adding weight), glute lift, clambshell, KB deadlift, KB Sumo Deadlift, Trapbar Deadlift, DB1 Stagger Deadlift, KB goblet squat

Neuromuscular Strength: Squat with theraband perturbation, Lunge, Step up with contralateral movement pattern, KB Squat (tempo manipulation), Single leg squat, Hip bridge (2 & 1 leg), Hip thruster, Light Kettlebells swing, KB1-in-out-deadlifts,,

KB1-cross-body-deadlift, KB1-cross-body-swings, DB1-suitcase-deadlift, KB2-front-squat, KB2-Deadlift

Balance / sensorimotor training (Open eyes rotate + vertical, Close eyes rotatio + vertical  1 or 2 legs, Wooble board, airex, bosu ball, Basic kettlebell drills for balance,

Other training Ankle Pumps, Gait Training (external task, theraband perturbation).
Additional training:

training non involved limb, trunk and hip core and cardioexercise
Cardio exercise

Aerobic condition, Bike, Crosstrainer, Skierg, gait re-education (Anti-gravity),
Other modalities

Goals for phase 2.

  • Initiate muscle activation and balance
  • Improve ROM with PROM 0-100 degree.
  • Control swelling
  • Use POLICE
  • 24/7 perspective – awareness of total load

Objective measurement


Aim 7-12 wks.

Continue aims from previously phase and add some individualized and sports specific exercises.

The big milestone will be the biodex testing after 12 wks.
Body weight exercise

Exercise suggestions

Mobility: Dynamic warm exercises, get inspired by gymnastics and track and field runners.

Strength Adduction, Abduction lift, Calf raises, BB romanian deadlift, BB Sumo Deadlift, Trapbar Deadlift, DB1 Stagger Deadlift, KB goblet squat, BB Deadlift Dorian,

Neuromuscular Strength: BB Squat, Lunge variation (back/forward/side), Step up with contralateral movement pattern include DB or KB, KB Squat (tempo manipulation), Single leg squat, Hip bridge / Hip thruster (add Slamball or disk to increase load), Kettlebells swing / high swing, KB1-in-out-deadlifts,,

KB1-cross-body-deadlift, KB1-cross-body-swings, DB1-suitcase-deadlift, KB2-front-squat, KB2-Deadlift, KB1-sumo-deadlift-high-pull, SB-Zercher-Squats, DB1-power-snatch, modified nordic hamstring, TRX Dragon Squat,
Balance / sensorimotor training (Open eyes rotate + vertical, Close eyes rotatio + vertical  1 or 2 legs, Wooble board, airex, bosu ball, Basic kettlebell drills for balance,

Plank variation, BW-atomic-sit-ups, BW-X-Sit-up, BW-side-v-sit (alt), DB2-plank-rows, disk-sit-up, disk-sit-up-get-up, bb-good-mornings(seated), bw-plank-leg-lifts, Renegade-row, renegade-row-burpee-shoulder-press
Condition exercise

Aerobic condition, Bike, running, Skierg, swimming, Ladder drills, jump, accelerations exercise.

Goals for phase 3
Objective measurement

  • Normal PROM (evt. small flexion decifit)
  • No Swelling

OBS: MyJump2 can be used to measure progression.


Aim 13-16 wks.

At this point we also want to integrate more strength and conditioning into the rehabilitation.
This could be adding

  • Explosive strength which are the maximum strength is produced in shortest amount of time. More simplified, how quick you can lift an item.

There are generally two ways that to work with explosive strength.

  1. explosive strength with light weights (20-60% of 1RM)
  2. explosive strength with heavy weights (>80& af 1RM)
  • Reactive strength (SSC)

Reactive strength is about our ability to go from performing an eccentric to performing an explosive concentric force (eg jump, throw, run). When we talk about reactive strength, we can divide the movements we perform during the time the movement takes, The stretch-shortening cycle (SSC). Activities which involves large range of motion in multiple joint are typically categorized as slow SSC movements (>250ms), while low range of motion are characterized as fast SSC (<250ms).

  • Maximum strength

Maximum strength is the maximum force you can produce during a given movement and duration. More simplified, so much weight you can put on your barbell and still lift it. Maximum lift is one of the main pillars of strength training. Maximum strength can be divided into

  1. Absolute strength: The absolute strength is what you can lift.
  2. Relative: Relative strength is your absolute strength divided by your bodyweight binft. If two athletes lift the same weight, they have the same absolute strength, but the athlete who weight less has a relative higher strength.

A milestone could be squat your bodyweight.


DB2-plank-rows, disk-sit-up, disk-sit-up-get-up, BB-good-mornings(seated), BW-plank-leg-lifts, BW-side-v-sit (alt), BW-atomic-sit-ups, Renegade-row, Renegade-row-burpee-shoulder-press, Mountian climbers, Disk-sit-up-get-up

Neuromuscular strength (See phase 3)

DB2-forward-lunge,  DB2-forward-lunge (alt), lunge walk,

KB1-power-clean-lunges, TRX-pistol-squat, KB-overhead-lunges-back, KB-overhead-lunges-walk, KB2-squat

Return to hopping / jump.

Long jump, Counter Movement Jump (CMJ), Split jump, Frog jump, Truck Jump, Burpee, Angle jumps, Wall jumps, Squat jumps, side to side jump (1 / 2 leg), 180° jumps, Pogos jump, box jump
Condition exercise

Aerobic condition, Bike, running, Skierg, swimming, Ladder drills, jump, accelerations exercise, swimming.

Goals for phase 4

  • Should be highly individualised and the patient should be very independent.
  • Focus on getting the player mentally ready for return to sport
  • Watch for sign of overloading.
  • S&C built up, power and force development, master risk situations,
  • Return to running after

16 weeks (Bizzini, 2012).
Objective measurement

The same as phase 3. Repeated to track improvements


Aim  +16 uger. Follow the progression. Return to training. Different prevention protocols and be used as return to training. More demanding testing be applied like Yo-yo test, T-Test.

Like the PEP-program (Mandelbaum et. al., 2005), FIFA 11+ (3 levels), Kicking progression for return to soccer following lower extremity injury (15 phases) (Arundale, A. 2015).

Should be highly individualised and the patient should be very independent.
Focus should also focus on getting the player mental ready for return to sport.
Objective measurement

The same as phase 3. Repeated to track improvements

  • Yo-yo , Bangsboo 2008
  • repeated shuttle-sprint ability (RSSA) test
  • Side Hop test (Normative value) (W.L.A. Velter Master thesis, Reference values for the Side Hop Test in healthy young adult athletes.)

OBS: Be carefull when testing