We squat to build leg strength, we sprint to get faster, and we jump to increase distinct force-time characteristics. In other words, we use different methods to optimize our lower limb capacity with the ultimate goal to improve sports performance, yet we frown upon closed change of direction (COD) drills due to their lack of specificity. If we want to prepare our athletes for unforeseeable worst-case scenarios in situ, however, these COD drills are a highly specific tool that builds physical antifragility.
This post aims to increase our understanding about the why of COD drills, then highlights the how, and finishes with practical examples showing the what. By no means have I originated the ideas presented here by myself, but rather from constant discussion about all things physical preparation with Sophia Nimphius (@DocSoph) and Anastasios Karamitros (@powerathleticsgymtraining).
Acknowledging Uncertainty in Our Decision-Making
Many approaches and coaching philosophies exist in the S&C community, although we share a common and universal denominator: I want my team or athlete to win! With this in mind along with my understanding of my role from a purely physical point of view, my goal is to help my athletes experience as much quality and quantity of deliberate practice as I can, absent any pathology. The only way to get better players is to give them opportunities to accumulate as much game exposure as possible (see Image 1).
Due to our limited training time, we need to pick methods that have the greatest potential while also having a beneficial risk-to-reward ratio to build antifragility specific to the demands in our sport. The solution for this exercise selection problem, however, depends on:
- The degree of uncertainty in our programming. Knowing what the athlete’s limiting factors are and how they’ll adapt to certain interventions is a highly complex and fluctuating process differing not only between athletes but also within the same athlete with respect to time.
- The amount of variance in our exercise selection is infinite. Thanks to Instagram and Twitter, we have access to a never-ending number of drills and exercises. We also can manipulate sets and reps, frequencies, durations, and work-to-rest ratios.
- The amount of scientific evidence to support our decisions is very small. Research experiments only tell us what happened under precisely defined conditions but not what happens considering all conditions that exist in reality. Philosophically, it is impossible to conduct research that’s as complex as reality, and applying evidence from reductionist research is only beneficial in theory. Also, we see a high interindividual response to every intervention, which makes it impossible to predict any adaptation on the individual level. But research evidence does provide a spectrum of adaptation that might occur.
The solution lies in simplicity and pragmatism. Up until recent attempts to translate research from ecological psychology in the hopes of facilitating S&C practice, closed COD drills were an integral part of many programs for a long time. This long presence provides a “Lindy-proof” of the justification and application of closed COD drills in the pursuit of building antifragile athletes.
It seems that the pendulum has now swung toward open skills with proponents selling the belief that drills without a perceptual-cognitive element won’t help our athletes.
On a side note, how perceptual-cognitive abilities that do transfer to in situ scenarios are best trainable is another topic. But keep in mind, there have been researchers studying this question for decades who have not come up with a definitive answer. Luckily the S&C community solved this problem with various types and progressions of 1v1 and mirror drills (I say this sarcastically).
Simplicity and Pragmatism of COD Drills
During COD tasks, athletes need to use their eccentric strength to decelerate or brake momentum and their isometric strength to maintain a stable and efficient intersegmental alignment—and not leak energy through potential weak links during the transition period. They also must use their concentric strength to reaccelerate in the new direction within 200ms on one leg while effectively controlling the center of gravity over the base of support.
Trying to determine which physical capacity is the limiting factor for each athlete while trying to improve it with established methods in subsequent intervention periods seems like an Ivory-Tower approach, assuming the availability of adequate resources to do so. What if deficits in any COD task—in a closed drill or in situ—are due to a lack of movement experience in controlling the athlete’s body positions and avoiding unnecessary movements, while effectively controlling and using mechanical braking forces to change direction? What if this is only present in one direction or off one limb and we’ve missed identifying this deficit?
If only we had a training method that addresses all of these potentially limiting factors with a high degree of mechanical specificity. Exposing athletes to a handful of simple, and therefore “non-Instagram-able,” COD drills in basic configurations will inevitably target—albeit with different emphases—all of the capacities and abilities mentioned above. Although we deal with complex systems, we certainly can help with simple yet effective interventions. Simplicity on the surface is often mistaken as a lack of effectiveness while entirely ignoring its benefits.
Prescribing these simple drills, however, requires a high degree of confidence about their effectiveness in what they can achieve. Increasing our pragmatic understanding about a couple of key variables we can manipulate to elicit a mechanical overload and build antifragility is good enough to ensure they work satisfactorily.
Favoring simplicity and pragmatism in my approach for antifragility, I use this heuristic in my daily work: force is force, and the accompanying strain to the body is strain to the body. It doesn’t matter which stimulus we use to elicit certain loads, surely our passive structures will adapt to it.
Specificity of Worst-Case Situations
As an S&C coach, I want to prepare athletes as much as possible for any biomechanical and physiological worst-case scenarios that can happen in their particular sport. I can minimize their risks from experiencing loads that put them in a suboptimal position to succeed in their task. When considering COD movements, one cannot ignore the accompanying injury risk to the knee and the prevalence of ligamentous pathologies in many invasion sports.Closed COD drills prepare athletes for biomechanical and physiological worst-case scenarios in their sport, says @DanielKadlec. #ClosedCODdrills Click To Tweet
One common biomechanical denominator associated with ACL injury risk during sidestepping tasks are knee valgus moments (KVM) that cause strain on the ACL. Loads exceeding the tissue capacity of the ligament will inevitably compromise an athlete’s orthopedic health. With this understanding, we can reverse engineer the causal relationship between KVM and ACL injury risk into COD drills. The idea is to microdose KVM within a specific movement pattern, supercompensate, and subsequently increase tissue capacity.We can reverse engineer the causal relationship between knee movements & ACL injury risk into closed COD drills, says @DanielKadlec.#ClosedCODdrills Click To Tweet
We know from biomechanical research that such variables as entry velocity, cutting angle, trunk alignment, and preparation time before the cutting motion have a direct relationship with the magnitude of KVMs. Manipulating at least one of these variables alters the mechanical demands upon the athlete, assuming sufficient motor competence to execute the drills with adequate intent.
- Entry velocity. Faster approach speeds result in greater KVMs. Prescribing distinct run-up intensities before the COD task or increasing the run-up distance affect the subsequent loading magnitudes. As most ACL injuries in situ occur at a travel velocity of 3.5-5ms-2 and KVMs are maximized at 5.5ms-2, this seems to be a sufficient speed to work toward. It’s also been reported that an ACL rupture occurs 17-50ms after ground contact during the weight acceptance phase. Hence, one can argue that maximizing exit velocity is necessarily needed in the pursuit of experiencing worst-case loads.
- Cutting angle. COD made to greater angles up to a certain degree result in greater KVMs. Cutting angles between 45-90° tend to be the range where the majority of non-contact ACL injuries happen. Athletes might perceive their affordances for these COD tasks as appropriate and miss to decrease their entry velocity sufficiently in the steps before the final cutting steps. The potential energy of the travel system then exceeds tissues capacities.
In other words, athletes think they can handle such aggressive COD movements, but “reality is often disappointing” (Thanos, 2018). Although during COD tasks of 90-180° high magnitudes of torque act on the athlete in all planes and directions while twisting and turning, no athlete will do that without having decelerated to a sufficient amount before (i.e., slam the foot into the ground and turn while traveling at a high velocity). Hence, this has a lower priority in my set-up, assuming the athlete has a proficient deceleration capacity (see Image 2).
- Trunk alignment. Lateral flexion and rotation of the trunk away from the intended COD during the final cutting step result in greater KVMs. Failing to align the trunk (this includes the lumbo-pelvic complex, torso, and arms) in a favorable position during the COD task decreases trunk sway and increases injury risk. Disturbing or delaying an adequate trunk alignment during a COD task with appropriate task constraints can further prepare the athlete for worst-case scenarios. Holding a weighted implement in one or both hands or crossing the arms throughout the tasks are simple methods to sufficiently alter the movement pattern.
- Preparation time. Less time to prepare for a COD task results in greater KVMs. Manipulating the time available to determine the direction an athlete cuts is likely one of our most impactful variables. The more time an athlete has to prepare, the less strenuous the COD tasks is, as the athlete experiences lower loads (see Image 3).
We can visualize this in a continuum: pre-planned COD drills followed by unplanned COD drills in response to a human stimulus, which are followed by an unplanned COD drills in response to a generic stimulus (i.e., flashy light or cone color). This might get confusing, as we define unplanned drills as open COD drills.
The only intention I have with these unplanned COD drills is to chip away an athlete’s preparation time and then increase mechanical loading and have zero expectations to improve any perceptual-cognitive abilities. Although generic stimuli are regarded as highly unspecific to react to—with which I agree—they are a potent tool to prepare for similar in situ scenarios when almost no time is available to prepare. Examples include times when vision is compromised, a ball has a funny bounce, or avoiding tackles. Also, as better athletes tend to have superior perceptual-cognitive abilities (see Image 4), COD drills in response to a human stimulus might not elicit sufficient loads to build antifragility further.
Video 1. Examples of how to manipulate variables to prepare an athlete for biomechanical worst-case scenarios.
Manipulating any of the variables mentioned above to elicit a sufficient mechanical load can help prepare your athlete for possible in situ worst-case scenarios, which are unavoidable. If your athlete experiences a load that results in high KVMs in situ for the first time, you have done an insufficient job preparing your athlete. The best case in this situation is that the athlete loses the 1v1 situation and the opponent scores. The worst case is either a hamstring or bone-patella-bone graft as your brand new ACL.
The argument that movement patterns in closed COD tasks and open COD in response to a stimulus are different—so we must train a different skillset separately—is flawed and redundant. Yes, movement kinematics are significantly different, but we use COD drills to enhance the underlying physical capacity in the same way we use all sorts of vertical jumps to increase various lower limb characteristics (think RFD or stiffness). Never have I seen an athlete on the pitch perfectly execute a CMJ as we do in the gym all the time. Both are methods to trigger adaptations to increase an athlete’s physical capacities.
Embrace the Chaos
As with all interventions, a periodized approach is possible. When going from low load to high load, we can do:
- slow to fast entry velocity
- low to high cutting angle
- absence to presence of task constraints
- pre-planned to unplanned to affect preparation time
- a combination of all variables
Also, the amount of exposure per leg is plannable and quantifiable. While this all is in accordance with every text-book, it lacks skin in the game. On day one of preseason, athletes will start being exposed to all sorts of movement patterns in their particular sport. You can either convince your head coach to only run drills without any COD—as you need to progress load intensities over weeks (right?)—or you can start to microdose worst-case loads in your training.
Another popular approach to reducing high-risk movement patterns is to explicitly focus on isolated kinematic features, such as distinct joint positions or segment interactions throughout the motion, and ingrain them repetitively. Whether this approach alters the movement pattern favorably outside of the particular drill is highly questionable.
As we know, movement is a function of the organism, the tasks, and the environment, and I want my athletes to be successful despite their situation. Hence, I very rarely cue distinct body positions or movement sequences. Instead, I expose my athletes to variable conditions (a constraints-led approach) and work on the underlying physical capacities so they can explore what movement patterns are best for each of them in their situation.
My Two Cents on COD for Sporting Success
With my work—increasing the physical capacity and preparing for worst-case scenarios—I have my athletes experience greater quantities and qualities of deliberate practice as well as high volumes of game exposure. The approach involves various simple and pragmatic COD drills to lower the risk of failure in worst-case scenarios and create success despite the often-compromised position they’re in.
Despite all the available evidence and the global experiences of the S&C community, “everything that is done in this world is done by hope” (Martin Luther, 1483-1546). We can only hope to do our athlete a service with our well-intended and reasonably justified interventions while acknowledging the inherent complexity of uncertainty of our profession.
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1. Lee, et al. “Effects of Pivoting Neuromuscular Training on Pivoting Control and Proprioception.” Medicine and Science in Sports and Exercise2014; 46(7): 1400-1409.