Speed Training: improving deceleration will benefit sports performance!

Improving your ability to slow down and stop rapidly might seem totally at odds with the goal of improving sports performance. But as John Shepherd explains, specific deceleration training drills will not only improve speed around the field or court, but can also reduce the risk of injury

Athletes and coaches invariably strive for maximum acceleration and absolute speed, increased endurance and greater dynamic agility – not the ability to slow down! But think of a footballer landing from a header and then turning to sprint into an open position, or a tennis player scampering to the net in order to retrieve a drop shot then stopping, turning and sprinting to the service line to get to a lob; it’s obvious that the ability to slow the body down as quickly as possible in order to make another movement or movements is critical to performance and is key to numerous field and racket sports.

Eccentric muscular action

Muscles contract in different ways to produce and control movement. Key to stopping the body when decelerating from a sprint or landing from a jump is the eccentric contraction. An eccentric contraction occurs when a muscle lengthens under load to control movement. A concentric contraction (which forms the basis of the majority of sports movements) occurs when a muscle shortens to produce movement.
Examples of eccentric contraction include:

The lowering phase of a biceps curl, when the biceps muscle elongates while under tension (from the weight);
Hamstring muscle lengthening that happens when sprinting (as it contracts during the return phase of the running action). This occurs when the foot leaves the running surface, travels up toward the butt and is then extended to a position in front of the body in preparation for the next stride. The hamstring muscle controls the acceleration of the lower leg, controlling and pulling the lower leg back down toward the running surface. Most hamstring (and muscle) strains occur during this eccentric muscular phase, which helps explains the value of specific eccentric muscular training (more later).

If an athlete’s muscles are not sufficiently eccentrically conditioned then the muscle fibres will be unable to optimally dissipate and control the force of the landing. These forces are considerable. For example, when landing from a drop jump (box height 80-100cm), the ankle joints can be subject to a load six to eight times that of the athlete’s body weight and a figure skater landing from a jump will have to absorb five to eight times their body weight(1).

Muscle fibre and eccentric muscle action and injury

Increasing eccentric strength will guard against injury

As indicated, developing specific eccentric strength can guard against injury. A number of studies have been conducted to consider the way men and women land in response to a jump with specific reference to anterior cruciate ligament (ACL) injury. The findings often indicate that women lack specific eccentric muscle strength, which is a contributory factor to their increased injury risk.

For example, researchers from North Carolina considered landing preparation as a factor in potential ACL injury(3). Three-dimensional video and electromyographic (EMG) data were collected for 36 recreational athletes (17 men and 19 women) as they decelerated during landing. Specifically, the team looked at knee and hip angular motion patterns during the flight phase before ground contact.

They discovered that these motions, plus quadriceps and hamstring activation patterns were different between the men and women. For example, compared to men, women tended to display:

Decreased knee and hip flexion (in this instance, lowering movements that could absorb some of the impact forces);
Increased internal rotation of the knee, increasing detrimental impact forces transmitted through the knee;
Increased hamstring activation before landing, with decreased hamstring activation after landing. Hamstring strength on landing has been identified as being important for stabilising the impact.

The researchers concluded that lower extremity motion patterns during landing of the stop-jump task are pre-programmed before landing, and that female subjects prepared for landing in a way that increased anterior cruciate ligament loading during their landings thus increasing the risk for non-contact ACL injury.

Thoughts of an expert

Conditioning deceleration

What are the best methods to condition deceleration and that all-important crucial eccentric contraction? In a recent study, researchers in Stockholm looked at two weights-based training methodologies(4). Fifteen men participated in a five-week study involving 12 workouts. Eight workouts were performed using concentric/eccentric leg extensions on a weights stack machine, while seven used a flywheel machine, which provided variable resistance and crucially, eccentric muscle overload. In this device, a large rotating wheel generates magnetic tension and provides extremely accurate control over the resistance generated – both eccentrically and concentrically.

For the study, both groups had to overcome comparable resistance using a similar muscular action. The key difference was that the flywheel machine allowed its users to experience greater eccentric loading.

The team tested for maximal isometric force across numerous angles and hypertrophy (muscle growth) in all four regions of the participants’ quadriceps. It was discovered that the flywheel trainers were able to exert more isometric force at all angles compared to the weight stack group. This could be attributed to the fact that eccentric strength is involved in holding and resisting muscular forces.

Although both groups experienced quadriceps muscle strength increases that were deemed not to be statistically significant, the flywheel group’s muscles displayed greater hypertrophy across all four regions. This led the researchers to conclude that more robust muscular adaptations occur following flywheel than weight stack resistance exercise, supporting the idea that eccentric overload offers a potent stimuli essential to optimise the benefits of resistance exercise.

Deceleration agility practices

Practicalities of eccentric weight training to enhance deceleration

To ‘lift’ eccentrically, an athlete needs two spotters and/or specifically constructed equipment. These eccentric lifts often use super-maximal loadings of 105-125% of the athlete’s normal one repetition maximum (1RM). This is because muscles are able to withstand greater eccentric than concentric loading due to increased fast-twitch muscle fibre and motor unit recruitment.

Using the bench press as an example, the bar should be loaded and the athlete assisted in lifting it into the ready position. The athlete should then lower the weight to a five count with the spotters on hand. At the bottom of the lift the spotters assist the athlete to return the bar to the stands. Note: the athlete only assists the return of the bar; they should not try to ‘press it back up’.

Plyometric training to enhance deceleration

Plyometric exercises are crucial when conditioning for dynamic deceleration. A plyometric exercise evokes a specific combination of muscular actions that enhances the athlete’s ability to absorb landing forces and (if required) produce dynamic stopping, jumping and cutting movements.

When an athlete lands from a jump, to leap into another, the muscles are ‘stretched under load’ (the eccentric contraction); in other words, the muscle fibres lengthen as they absorb the impact. This process also stores energy. The stronger the athlete’s muscles are eccentrically, the greater control they can exert during landing. Therefore, the strain that is placed on the knee and ankle joints is lower, and more power is available for the subsequent concentric contraction.

You can think of an eccentric contraction from a jump landing as a bit like cocking the trigger on a gun; it prepares the muscles to fire with much enhanced concentric power when the ‘hammer’ is released, or, in the athletic example, the athlete leaps into a jump (or similar dynamic movement).

Table 1: Relationship between weight lifted (as a percentage of 1RM) and the development of different types of ‘sports strength’, including deceleration

Conclusions

This article outlines the importance of specific conditioning for deceleration. Coach and athlete should incorporate specific drills and practices into a carefully balanced training plan designed to get the most from these abilities and reduce injury risks. The drills outlines above will improve eccentric strength in the relevant muscles

John Shepherd MA is a specialist health, sport and fitness writer and a former international long jumper
References

1. Tudor Bompa et al. Periodisation Training for Sports (second edition); Human Kinetics 2005
2. Med Sci Sports Exerc 2000; 32(4): 812-9
3. Am J Sports Med 2007; 35(2): 235-41. Epub 2006 Nov 7
4. Eur J Appl Physiol 2008; 102(3): 271-81. Epub 2007
Oct 10

Selected deceleration improving plyometric exercises

Get on the road to gold-medal form and smash your competition.
Try Peak Performance today for just $1.97.

Tagged in speed training
Privacy Policy [opens in new window]
Please Login or Register to post a reply here.