The one that patients will do! 

I don't think that there's a best way - but I know that Grethe Mykleburst from Norway have made som great studies and programmes about ACL preventions & rehabillitation training. 

Exercises commonly utilized in neuromuscular training programs include: plyometric and movement, core strengthening and balance, resistance training, and speed training. 

a close relationship exists between ACL injuries and subtalar dysfunction with functional hallux limitus. I suggest to manipulate the hindfoot to free the locked subtalar joint (if locked) before to start with proprioceptive exercises on one leg, core strengthening and plyometry

I thought that these 2 canine publications might help.

I have not came across a particular type of exercise to prevent ACL injuries. However, I agree with what Raju mentioned above. Each case is unique and a proper screening on muscle length, muscle strength imbalances and weaknesses is essential. In addition to plyometric exercises, I would recommend strengthening the hip abductors eccentrically as they control the valgus position of the knee when standing on a single limb. The hip abductors and abductors are the long forgotten muscles of the hip joint. Good luck. 

I agree with that both Mohamed and Tanju mentionde above

In the 1990’s a vast quantity of research was done to determine ways to prevent ACL injuries and predictive measures that could be used to identify those in need of such interventions (primarily female athletes). ACL rehabilitation protocols, some evidence based, some developed through trial and error, were developed that included neuromuscular training with aspects being touted as preventative. It is interesting to note that much of the information discovered between 1990 and 2005 has been ignored as individuals within the medical and rehabilitation profession continue to seek new remedies because they didn’t learn from the past.

In ACL rehabilitation, it has been demonstrated that functional deficits that can be linked to “neuromuscular” dysfunction persist for years after those undergoing ACL reconstruction have been discharged. One of the most striking, and seemingly completely ignored because it doesn’t fit the current orthodoxy, is the persistence of quadriceps weakness in the involved limb. Currently the focus of many researchers who advocate “closed kinetic chain” rehabilitation over “open kinetic chain” rehabilitation interventions, is on the hip abductors because those athletes who experience “non-contact” ACL injuries have what these people see as weakness and lack of endurance of the hip abductors which causes the knee to be predisposed to knee to valgus stress when cutting, landing from a leap, etc.

Once again, in the 1990’s researchers investigating the cause for a greater incidence of “noncontact” ACL injuries in female athletes discovered that females tend to cut differently than males. As any coach can tell you, girls and boys run differently. These researchers discovered that girls tended to allow their knees to collapse into a position of high valgus deviation as they decelerated an the knee flexed in preparation for the cut, this then became a strong varus deviation as the knee extended and they accelerated in the new direction. The male subjects had very little varus or valgus deviations as they cut, it was decelerate as the knee flexed, accelerate as the knee extended; keeping all of the forces in the sagittal plane. Additionally, other researchers discovered that not only were female athletes significantly weaker than male athletes, even when the loads were normalized, the relationship was especially more pronounced in the hamstrings and quadriceps, and the quadriceps:hamstring ratio.

In 2003, Salem, Salinas, & Harding published a paper in the Archives of Physical Medicine and Rehabilitation, in addition to other presentations at scientific meetings that demonstrated that the body had different motor programs for extending the lower extremity in a “closed kinetic chain” situation. If limb dominance was ascertained by “which leg do you kick a ball with?” The body used a hip dominant strategy on the non-dominant, support limb; and a knee (quadriceps) dominant strategy on the dominant, kicking leg. ACL injuries and reconstruction resulted in the injured leg adopting a “hip dominant” strategy. This finding has been validated in countless studies over the past 12 years.

Also of significance, the strong bias toward “closed kinetic chain” exercise for ACL rehabilitation has probably compounded the problem. Research has failed to discover the “best” way to perform the squat exercise. The reason is because the “best” way to squat is completely dependent on the skeletal arrangement of the individual’s hips. In physical therapy it is understood that some people’s hips are in an anatomically determined position of anteversion, retroversion, or neutral. This causes the knees and feet to have positions that are congruent with the position of the hip or incongruent with the hip position. Persons who squat in their “anatomically correct” position perform better, with proper neuromuscular input to activate the various muscles through what amounts to primitive reflex motor programs, while those who squat in a manner that is not “anatomically correct” produce alterations in neuromuscular coordination resulting in the adoption of faulty motor programs for squatting. These faulty programs affect how the body performs all activities. Therefore, as one uses proprioceptive (balance training) in the rehabilitation process after the ACL injury, similar activities and progression models would be used preventatively.

The athlete must be examined to insure that they are properly aligned when performing squats, proprioceptive training must become part of the training program, open chain, isolation exercises for the quadriceps and hamstrings must be performed (this is the topic of another paper, if you are interested), and specific high level plyometric and agility drills must be used when the strength and motor control issues have been adequately accomplished. Attached to this answer you will find some other materials related to this answer.      

Article Bilateral kinematic and kinetic analysis of the squat exerci...

Article SIGNIFICANT SIDE-TO-SIDE DIFFERENCES IN JOINT MOMENTS DURING SQUATTING

Article ACL REHABILITATION - TRACK AND FIELD

Conference Paper Biomechanical Analysis of the Back Squat Exercise: A Compari...

Conference Paper An investigation of the relationship between an open kinetic...

Conference Paper An evaluation of the return to activity criteria of a single...

Querido amigo te escribo en castellano que será mejor. Fabulosamente bien te lo han descrito mas arriba todo, pero mira el protocolo FIFA 11+, en la web de FIFA, donde encontraras verdaderos ejercicios prácticos para prevenir este tipo de lesiones.

un abrazo.

Hope the information presented below is of some use. Information is pertaining to an uninjured / intact ACL.

Neuromuscular Training (NMT) / Preventive Neuromuscular Training (PNMT) defined:   Neuromuscular and biomechanical (neuromechanical) typically include kinematics, kinetics, and the timing and magnitude of the muscular activation and force production.(Shultz et al. 2008) Specific exercises / training can include, individually or in combination, plyometrics, strengthening and proximal control (Sugimoto et al. 2014) and balance, education, and feedback should be part of this training.(Hewett et al. 1996; Myer et al. 2005; Oñate et al. 2005; Hurd et al. 2006; Myer et al. 2006; Pollard et al. 2006; Herman et al. 2009)

ACL Injury Mechanism:   In vivo ACL strain (causing ACL injury / rupture) is a results of  maximal load (approximately 2300 N (Yeow et al. 2008)) and timing of ground reaction forces.(Cerulli et al. 2003) A more erect / upright torso is associated with increased vertical ground reaction forces.(Blackburn et al. 2009; Shimokochi et al. 2009; Norcross et al. 2013) Anterior tibial translation increases as quadriceps contraction intensifies, (Myers et al. 2012) therefore, an upright stance in the early stages of ground contact on landing (resulting eccentric deceleration of quadriceps) seems to be associated with an ACL injury.(Decker et al. 2003; Houck et al. 2006; Pollard et al. 2007; Schmitz et al. 2007)

As detailed below, there is much controversy regarding the efficacy of NMT / PNMT programs.

Regardless, it is crucial to note, if NMT / PNMT programs indeed prevent ACL injury, are researchers suggesting that these programs are overcoming the inherent neuromuscular / musculo-ligment tendon-stretch reflex delay which Markolf et al (1978) and Pope et al (1979) had stated that ACL injuries occur too quickly for reflexive muscular activation; specifically intrinsic delay in activation of the hamstring muscle group to protect the ACL from injury.

Twenty-some years later, the 1978 and 1979 information was validated by Simonsen et al. (2000) who demonstrated that the rapid concentric hamstring contraction, even during maximal activation, has only a marginal ability to protect and thus reduce ACL injury. Additional validation of the initial 1978 and 1979 data also showed there is a latency period between preparatory and reactive muscle activation that results in an electromechanical delay (Otago et al, 2007; Reed-Jones and Vallis, 2007; Lephart et al, 2002; Bell and Jacob, 1986).

Further, as stated below (item V.2, VI.2, and VII.2) “ACL injury rates and the associated sex disparity have not yet diminished.” and “Overall ACL injury rates and the associated sex disparity have not yet diminished.” (Shultz et al, 2010, 2012, 2015, respectively).

In addition, even in the best case scenario of NMT / PNMT are able to ‘protect the ACL’ form non-noncontact injury, numerous researchers have clearly illustrated that the benefit(s) of NMT /  PNMT programs are not long lasting – similar to physiological oerformance parameters (agility, flexibility, power, strength, etc), items IV.3, V.4, VI.3, and VII.6 below and numerous references listed below.

Further, concern(s) remain regarding NMT / PNMT programs being able to enhance / ‘re-train:

(1) body’s motor-learning system to react to all possible ‘ACL injury-causing’ incidences; item VI.4 below and (Pantano et al. 2010; Benjaminse et al. 2011)

(2) the ‘protective mechanism(s)’ when the body / muscle(s) are fatigued and the risk of ACL injury is increased (items IV.2, V.5, V.6, VI.6, VI.7, and VII.7)     

Observation from Shultz et al, 2008, ACL Research Retreat IV (ADD INFO as per below

(IV.1) Fatigue alters lower limb biomechanical and neuromuscular factors which can lead to increasing ACL injury risk.(McLean et al. 2004; Chappell et al. 2005; Orishimo et al. 2006; Kernozek et al. 2008)

(IV.2) The effect of fatigue is most pronounced when combined with unanticipated landings, causing substantial central processing and central control compromise. (Blackburn et al. 2008)

(IV.3) The protective effects of ACL injury prevention training programs appear to be transient.(Graves et al. 1988; Häkkinen et al. 2003; Petibois et al. 2003)

Observation from Shultz et al, 2010, ACL Research Retreat V

(V.1) Intervention programs have been shown to reduce the incidence of ACL injuries.(Hewett et al. 1999; Myklebust et al. 2003; Olsen et al. 2004; Mandelbaum et al. 2005; Hewett et al. 2006; Gilchrist et al. 2008; Yoo et al. 2009)

(V.2) Although these results are promising, ACL injury rates and the associated sex disparity have not yet diminished.(Shultz et al. 2010)

(V.3) The ideal ACL injury-prevention program has yet to be identified.(Shultz et al. 2010)

(V.4) The protective effects of ACL injury-prevention training programs appear to be transient.(Häkkinen et al. 2000; Petibois et al. 2003; Shultz et al. 2010)

(V.5) Fatigue alters lower limb biomechanical and neuromuscular factors and is suggested to increase ACL injury risk. (Chappell et al. 2005; Orishimo et al. 2006; McLean et al. 2007; Benjaminse et al. 2008; Kernozek et al. 2008; Lipps et al. 2013)

(V.6) The effect of fatigue is most pronounced when combined with unanticipated landings, causing substantial central processing and control compromise.(Borotikar et al. 2008; McLean et al. 2009)

Observation from Shultz et al, 2012, ACL Research Retreat VI

(VI.1) Intervention programs have been shown to reduce the incidence of ACL injuries.(Hewett et al. 1999; Myklebust et al. 2003; Mandelbaum et al. 2005; Olsen et al. 2005; Hewett et al. 2006; Gilchrist et al. 2008; Yoo et al. 2009)

(VI.2) Overall ACL injury rates and the associated sex disparity have not yet diminished.(Shultz et al. 2012)

(VI.3) Improvements in movement quality after 12 weeks of training do not appear to be retained once preventive training programs end.(Shultz et al. 2012)

(VI.4) The transition from conscious awareness during technique training sessions to unexpected and automatic movement during training or game involves complicated motor control elements that might not fit in explicit learning strategies.(Beek 2000)

(VI.5) According to Shultz et al (2010), “We must determine the performance enhancement benefits associated with regularly performing preventive training programs.”(Shultz et al. 2010)

(VI.6) Fatigue alters lower limb biomechanical and neuromuscular factors that are suggested to increase ACL injury risk.(Chappell et al. 2005; Orishimo et al. 2006; McLean et al. 2007; Kernozek et al. 2008)   132–135,189

(VI.7) The effect of fatigue on movement mechanics is most pronounced when combined with unanticipated landings, causing potentially adverse changes to central processing and control compromise.(Borotikar et al. 2008; Greska et al. 2012)

Observation from Shultz et al, 2015, ACL Research Retreat VII

(VII.1) “Injury-prevention programs have been shown to reduce the incidence of ACL injuries.”(Shultz et al. 2015)

(VII.2) However, overall ACL injury rates and the associated sex disparity have not yet diminished.(Shultz et al. 2015)

(VII.3) Various injury-prevention programs that incorporate elements of balance training, plyometric training, education, strengthening, and technique training or feedback have been shown to reduce incidence of ACL injury in females(Hewett et al. 1999; Myklebust et al. 2003; Mandelbaum et al. 2005; Olsen et al. 2005; Hewett et al. 2006; Gilchrist et al. 2008; Yoo et al. 2009; LaBella et al. 2011; Sadoghi et al. 2012) or alter biomechanical and neuromuscular variables thought to contribute to ACL injury.(Hertel et al. 1996; Oñate et al. 2005; Hurd et al. 2006; Myer et al. 2006; Myer et al. 2006; Pollard et al. 2006; Herman et al. 2009; Leppanen et al. 2014; Ter Stege et al. 2014; Stevenson et al. 2015)

(VII.4) Most exercises implemented in male soccer players to prevent noncontact injuries involve eccentric exercise, balance, and specific hamstrings eccentric training.(McCall et al. 2014)

(VIII. 5) However, data regarding the effectiveness of prevention programs to reduce ACL injuries or modify risk factors for ACL injuries in male athletes are scarce and inconclusive as to recommendations for single-legged and multidirectional maneuvers.(Alentorn-Geli et al. 2014; Sugimoto et al. 2015)

(VII.6) Improvements in movement quality after 12 weeks of training do not appear to be retained once the program ends.(Shultz et al. 2015)

(VII.7) Although investigation showed that the ACL is susceptible to fatigue failure during repetitive simulated pivot landings and a smaller cross-sectional area of the ACL is at greater risk for such failure (Lipps et al. 2013) it is not known if it is a single episode or multiple episodes (or both) that causes gross failure of the ACL.(Shultz et al. 2015)

Plyometric retraining - jump landing.

See Prof Lars Engebretsen's work from Norway - top stuff

Exercises that promote proprioception and neuromuscular balance and training are usually plyometric and isometric exercises, speed training, balance training, stretching and strengthening the lower limb muscles without forgetting hip stabilisers. Upper body and core muscles play their role at the balancing process. 

Thanks for your feedback Dr. Zafiropoulos. What you state is correct these are exercises used by many athletes to prepare for elite competition and as some publications have suggested as part of ACL prevention protocol.

However, as stated by the  Dr. García, ("... best way to prevent ACL injuries?") do these exercises prevent ACL injuries?  If so, by what mechanism(s)?