[8-minute read]

Jacob Stockdale, Sabrina Ionescu, Kylian Mbappé, and Sarah Rowe are all extremely talented sportspeople with the ability to leave defenders for dust. Their ability to decelerate, control force, and re-accelerate in a short period of time is what gets them past defenders in a game, and it’s why they’re considered to be both talented athletes, and nightmares to defend against.

The ability to trick a defender into thinking you are moving one way, only to accelerate in a different direction is a vital and useful skill in almost every team sport. Although deceleration and change of direction (COD) come hand in hand, tricking a defender is not the only use for them.

We know that deceleration occurs more often than acceleration in team sport due to the unpredictability of the game (Harper et al, 2019). Therefore, the ability to control one’s mass and force to the point of stopping is necessary for every field sport.

Deceleration /

Deceleration is defined as how quickly we can reduce velocity with respect to time. We engage in deceleration numerous times a day, in both normal life and sport. While it is a natural movement for most, it is also important to understand the mechanics of deceleration and ensure our athletes are slowing down safely.

The task of slowing down is often under a short time constraint and so experience and understanding of such a task is an important skill that all athletes should hold.

“The forces applied to the body when decelerating can be exceptionally large in magnitude, especially when the time over which these forces must be absorbed is small” 

– Hewit et al, 2011

Our ability to decelerate efficiently, i.e with proper mechanics in the appropriate time, is dependent on a number of physical capabilities. By designing training around these capabilities to enhance the athletes’ ability to perform them to their full potential, we will help improve athletic ability and reduce the risk of injury.

Efficiency in deceleration is dependent on the athlete’s:

1. Eccentric Strength; and,
2. Neuromuscular Control

The mechanics of deceleration are centered around the lowering of one’s mass with minimal trunk change. Optimal linear deceleration technique involves:

1. Heel strike to full foot contact
2. Lowering of hip height
3. Neutral trunk i.e minimal trunk change (flexion, extension, or rotation) to that of acceleration

A term coined by Jonas Dodoo, Founder of Speedworks Training, which nicely describes this sequence of events is “Quiet Sitting”. The athlete lowers and controls their mass over time into a position similar to that of sitting on a chair, i.e back straight, knees bent, and hips slightly higher than knees.

Jonas Dodoo delivered a very interesting webinar on the topic of deceleration which you can find on his website. He also discussed mechanics on Episodes 15 and 16 of our partners Deely Sport Science’s Locker Room Podcast which you can listen to here.

In order to ensure the athlete can carry out this task efficiently, we must ensure they have the strength and control to do so. We’ll now explore some training methods that can be used to develop this ability.

Training to Improve Deceleration Ability /

1 / Strength

• Eccentric variations of lifts, Bilateral and Unilateral, such as: Eccentric Squats and Single-Leg RDL
• Isometric movements, Bilateral and Unilateral, such as: Isometric Rear-Foot-Elevated Lunge and Isometric Bodyweight Squat

2 / Locomotor Skill Development

• Deceleration following acceleration
• Reaction games which require controlled deceleration in an appropriate time
• Reaction games that require rapid, controlled deceleration as quickly as possible

It is vital to understand that we must develop an athlete’s ability to decelerate correctly and in a controlled manner before we put them under change of direction tasks. The precursor to every change of direction task is deceleration, which means if we cannot decelerate well we will be unable to change direction well.

“Develop deceleration technique and ability first, change of direction second” 

Change of Direction /

Note: While there is an ongoing discussion with regard to the difference between change of direction (planned) and agility (reactive), for the purpose of this blog on the technique & development of the ability to change direction, we will discuss both as one.

As mentioned above, change of direction is a task that occurs in nearly every sport. The ability to decelerate, control, and accelerate in a new direction is seen in cutting/stepping in rugby, chasing an attacker in soccer, and transitioning from defence to attack in GAA. Changing direction is a vital skill, and similar to deceleration, we must ensure that the athlete can complete the task efficiently.

Breaking down change of direction

Change of direction is a combination of 3 phases:

• The Braking Phase / Slowing down
• The Plant Phase / Transitioning from braking/eccentric movement to acceleration/concentric movement
• The Propulsive Phase / Re-accelerating

Researchers argue the effect of strength and power training on the improvement of change of direction performance, with a 2008 meta-analysis stating that “exercises which more closely mimic the demands of changing direction, such as horizontal jump training (unilateral and bilateral), lateral jump training (unilateral and bilateral), loaded vertical jump training, sport-specific change of direction training, and general change of direction training” have a greater impact on the performance of COD (Burghelli et al, 2008).

We have further developed our understanding of the task since this review, with new studies stating that although previous studies found no improvement in change of direction ability following strength & power training. However, what those studies were testing for may not have been valid measures of change of direction ability (Nimphius et al, 2017)

In support of the above, we know that deceleration immediately precedes changing direction. Therefore, strength training that would improve our deceleration ability (detailed above) will also improve our change of direction ability. When we break it down, changing direction is a reactive, eccentric-to-concentric task so improving strength, control, and power in all those attributes would serve to improve our ability to complete the task of changing direction.

However, as it is reactive there is also the need to develop and perfect our neuromuscular control in order to maximize the time in which change of direction can occur efficiently.

Rich Clarke of the UKSCA also lent his expertise in the area on Episode 7 of the Deely Sport Science Podcast available here.

Training to Improve Change of Direction Ability /

• Eccentric Bilateral and Unilateral Movements – Linear and Lateral, such as: Front Squat and Single-Leg Squat
• Concentric Bilateral and Unilateral Movements – Linear and Lateral, such as: Deadlift and Side Lunge
• Isometric Bilateral and Unilateral Movements – Linear and Lateral, such as: Single-Leg Hold and Isometric Lunge
• Reactive/Plyometric Bilateral and Unilateral Movements – Linear and Lateral, such as: Pogo Hops and Drop Jump
• Acceleration Technique and Ability
• Planned COD to develop technique and coordination
• Reactive or unpredictable COD to challenge technique and coordination

Conclusion /

Deceleration and change of direction come hand in hand in a lot of sports, and so the development of an athlete’s efficiency in both tasks is vital. An important consideration for coaches when developing these skills is the athlete’s uni/bilateral eccentric, concentric, and isometric strength. The athlete’s technique is king at all times, but as these tasks can often require the athlete to control forces varying from 1.5 to 2 times their bodyweight, it is important that the neuromuscular system is also able to handle such force to minimize injury risk.

Focus should absolutely be placed on developing deceleration and change of direction in training, progressing from controlled, planned scenarios to more chaotic, unpredictable scenarios with stimuli in order to replicate performance-like situations.

References

• AthleticPerformanceToolbox net, 2017 – “Deceleration” by Jeremy Shepard https://athleticperformancetoolbox.net/speed-and-agility/deceleration
• Harper, D.J., Carling, C. & Kiely, J. High-Intensity Acceleration and Deceleration Demands in Elite Team Sports Competitive Match Play: A Systematic Review and Meta-Analysis of Observational Studies. Sports Med 49, 1923–1947 (2019).
• Hewit, Jennifer MSc, CSCS; Cronin, John PhD; Button, Chris PhD; Hume, Patria PhD Understanding Deceleration in Sport, Strength and Conditioning Journal: February 2011 – Volume 33 – Issue 1
• Nimphius, S., Callaghan, S., Bezodis, N. and Lockie, R. (2017). “Change of Direction and Agility Tests.” Strength and Conditioning Journal, p.1
• Simplifaster.com, 2018 – Key Concepts in Preparing for Agility and Change of Direction” by Matt Kuzdub. https://simplifaster.com/articles/agility-change-of-direction/