This is a post by Warren Young, PhD,(firstname.lastname@example.org ) Coordinator of Master of Strength & Conditioning, Federation University Australia, Ballarat, Australia. In my opinion Warren and his colleagues have done more to define agility and its parameters from a research perspective than anyone I know. Warren is an applied scientist who has always been open to dialog with coaches. A little-known fact is that Warren was one of the developers of the Reactive Strength Index. This post although directed to soccer, transcends soccer.
After studying and writing about agility in sport for several years, my views have evolved. Although I have presented my own research and research of others in scientific and coaching journals, the following discussion allows for a more complete story about how I see training agility to enhance sports performance. This discussion especially applies to invasion sports, such as football codes, and my personal experience has mainly been in Australian football (AF). However, I believe this discussion applies equally as well to soccer, because both AF and soccer can both be described as “360 degree” sports, where players and the ball can move in any direction. I have decided to use examples here that are applied to soccer.
Agility in soccer
Agility seems to be a rather unique quality in soccer, and is not an easily defined skill like vertical jumping or a linear sprinting. In fact, I’m not even sure if agility should be thought of as a physical quality because it is a complex open skill. But more about that later.
Rather than debating what the definition of agility is, I think the best way to understand it is to view it in the context of a game. Agility in soccer depends on whether it is performed by the attacker in possession of the ball, or if it is performed by a defender. Many agility scenarios come down to a 1-on-1 contest, where an attacker aims to evade an opponent to progress down field, or to create time and space from opponents to pass the ball to a team mate in a more advantageous position. The aim for the defender is to move effectively to either tackle and win possession, or just to create enough pressure to produce a turnover. So agility is about “effective movement” to achieve an outcome. Effective agility is not always about how fast a player can move in multiple directions. In fact, if a defender charges at the attacker as fast as possible, this “over-commitment” makes the defender more susceptible to evasion by the attacker. To achieve a successful outcome, the movement strategy must be “measured”. A defender may approach the attacker cautiously and apply pressure simply by corralling the attacker so he or she can’t evade or get into space.
The movement strategies of both players in the contest are influenced by factors such as the position of other attacking and defending players, as well as their location in relation to the boundaries of the field. Therefore, the attacker and defender must pay attention to their immediate surrounds, and this contributes to the cognitive demand of their agility skill.
An attacker who wants to evade an opponent will constantly monitor the defenders movements to determine if he or she can be successfully deceived. If the defender shifts his or her body weight in one direction, the attacker may take advantage of this momentum to cut to the opposite direction. So the eventual evasive strategy is a response to stimuli provided by the defender. Conversely, the defender watches the attacker’s body to try to pick up clues about which way he or she will turn. To complicate the decision-making process, the defender also has to perceive the position of surrounding players in case the attacker attempts to quickly pass the ball. Therefore, the options that could play out are many and varied, and adds to the decision-making demands of the agility scenario for all players in the contest.
It is important to recognise that in soccer, each agility scenario is likely to be unique. The relative positions of the players in the contest, the speed and angle at which they are moving, and the movements of all the players around them will never be exactly the same. If a lateral change of direction is performed by an attacker or defender, the angle of the cut will be somewhat different in each agility scenario.
A Strength & Conditioning approach to agility
Returning to the question of whether agility is a physical quality or a sport skill, the preceding discussion suggests agility should be viewed as an open skill; that is, a skill that is influenced by many unpredictable factors. As such, it is not always clear who is responsible for developing agility in a team. Is it the responsibility of the football coaches who teach other sport skills, or is it the strength & conditioning (S&C) coaches who should integrate agility training into their speed program? The approach usually taken by S&C coaches is to break a skill down into component parts, and create exercises to enhance the movement. An example is the use of Olympic lifts or jump squats to develop power in a “triple extension” (hip, knee and ankle extension), with the intention of enhancing sprint or jump performance. If this reductionist approach is used to train agility, it is likely for the S&C coach to focus on the change-of-direction movement in isolation. Examples include practising deceleration or stopping hard, side-stepping, back pedalling, and shuffling. Often these pre-planned movements are directed by the use of obstacles such as cones, poles and ladders. These types of drills are now typically described as “change-of-direction speed” (CODS) rather than agility. The isolation of COD movements from agility may have been encouraged by many authors who refer to a model of agility that I published in 2002 (11). This model was an attempt to identify the various factors that contribute to agility performance, and it indicated that agility was determined by two main factors: the COD movement and a cognitive component. After considering more recent research, I have rejected this part of the model and revised it in 2015 (9) to remove the reference to CODS. Instead, agility is described as being determined by three components; technical (movement skill), physical (eg. strength qualities), and cognitive (eg. decision-making). The reason that CODS should not be seen as a component of agility, but rather as a separate skill, is because when a stimulus is included to a COD task, agility technique changes (3,7). This means that a change-of-direction movement and cognitive factors are dependent on each other, and should not be isolated. So I believe that we should try to avoid training and testing CODS in isolation, especially when the movements are directed by obstacles that do not exist on the football field.
Limited transfer from change-of-direction drills
Here are some reasons why I believe that CODS training has limited transfer to agility performance on the competition field:
Recommended ways to train agility in soccer
So how should agility be trained? There are two approaches that follow from the previous discussion. The first is training with 1-on-1 contests that are designed to replicate agility scenarios in games. Essentially, the attacker should attempt to beat a defender by dribbling the ball to a designated position. At the same time, the defender moves in response, and attempts to apply pressure or tackle to dispossess the attacker. To allow each player to experience game-like set-ups, each scenario should begin differently to create variability. Players should start in different positions within a designated space so that they approach each other at different speeds, and view each other’s bodies and movements from varied perspectives. The speed at which the players move, and the space in which they have to move, will influence their decision-making and movement strategies. Players should perform multiple trials in the roles of both attacker and defender because the agility demands are different. For example, an attacker may perform deceptive actions while watching the defender to see if he “buys a fake”, and a defender will watch the attacker and try to anticipate or react to a fake. Players will learn organically and implicitly what cues to focus their attention on. There is no need to give coaching instructions to explicitly state where the player should look and how to react. Implicit learning of motors skills has been shown to be effective (12), and more robust under pressure (4,5,6).
A second approach to developing agility skill is with small-sided games (SSG). One advantage of SSG (eg. 3 v 3 on a reduced sized pitch) is that with less players, there is more involvement in contests for each player, compared to full competition games. The greater frequency of agility events in SSG provides a more powerful training stimulus than a regular game. Another advantage of SSG is that they provide variability and unpredictability of agility scenarios. Each player is exposed to the movement styles and strategies of multiple opponents, and the position and movement of all players on the pitch must be considered in agility decision-making. Therefore, SSG are the only way to replicate the complex cognitive demands of competition. Research has also demonstrated that SSG are effective for developing sport specific agility in elite junior soccer (1) and Australian football (12) players.
I’m sure my views on this subject will continue to evolve, but hopefully this will spark some further discussion.