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Efficient Deceleration: The Forgotten Factor in Tennis-Specific Training

Authors:
  • United States Tennis Association
  • Rehab Plus Sports Therapy Scottsdale & Vice President Medical Services ATP World Tour

Abstract and Figures

EFFICIENT DECELERATION IS PARAMOUNT TO ALLOW FOR FAST AND EXPLOSIVE CHANGES OF DIRECTION. BECAUSE MOST TENNIS POINTS HAVE BETWEEN 3 AND 7 CHANGES OF DIRECTIONS, THE DEVELOPMENT OF THE COMPONENTS IN CHANGE OF DIRECTION MOVEMENTS IS A MAJOR COMPONENT OF COMPETITIVE PLAY. TRAINING FOR TENNIS REQUIRES A STRONG UNDERSTANDING NOT ONLY OF THE ACCELERATION ASPECTS OF MOVEMENT BUT ALSO THE NEED FOR TENNIS-SPECIFIC DECELERATION. IN THIS ARTICLE, WE REVIEW TENNIS MOVEMENTS FROM BOTH AN UPPER- AND LOWER-BODY PERSPECTIVE AND DESCRIBE THE IMPORTANT COMPONENTS OF TENNIS-SPECIFIC DECELERATION WITH PRACTICAL EXAMPLES OF DECELERATION TRAINING IDEAS.
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Efficient Deceleration:
The Forgotten Factor in
Tennis-Specific Training
Mark S. Kovacs, PhD, CSCS,
1
E. Paul Roetert, PhD,
1
and Todd S. Ellenbecker, DPT, CSCS
2
1
Player Development, United States Tennis Association, Boca Raton, Florida;
2
Physiotherapy Associates, Scottsdale,
Arizona
SUMMARY
EFFICIENT DECELERATION IS PAR-
AMOUNT TO ALLOW FOR FAST
AND EXPLOSIVE CHANGES OF DI-
RECTION. BECAUSE MOST TENNIS
POINTS HAVE BETWEEN 3 AND 7
CHANGES OF DIRECTIONS, THE
DEVELOPMENT OF THE COMPO-
NENTS IN CHANGE OF DIRECTION
MOVEMENTS IS A MAJOR COM-
PONENT OF COMPETITIVE PLAY.
TRAINING FOR TENNIS REQUIRES
A STRONG UNDERSTANDING NOT
ONLY OF THE ACCELERATION AS-
PECTS OF MOVEMENT BUT ALSO
THE NEED FOR TENNIS-SPECIFIC
DECELERATION. IN THIS ARTICLE,
WE REVIEW TENNIS MOVEMENTS
FROM BOTH AN UPPER- AND
LOWER-BODY PERSPECTIVE AND
DESCRIBE THE IMPORTANT COM-
PONENTS OF TENNIS-SPECIFIC
DECELERATION WITH PRACTICAL
EXAMPLES OF DECELERATION
TRAINING IDEAS.
INTRODUCTION
For competitive tennis players,
exceptional movement is a
requirement to achieve success
in junior tournaments as well as at the
collegiate or professional level. Accel-
eration focused training is common in
strength and conditioning programs
for tennis players; however, less
emphasis is sometimes given to the
importance that effective deceleration
training plays in both upper- and
lower-body movements of the tennis
athlete. The lower body needs to
perform large decelerations to prepare
for and recover after groundstrokes
and volleys, as well as during the
follow-through and landing phase of
the serve (29). The upper body,
particularly the muscles of the upper
back and posterior aspects of the
shoulder, feature the major muscles
that help decelerate the upper limbs
after ball contact in serves, ground-
strokes, and volleys (30). As such,
deceleration needs to be considered
a vital component of a competitive
tennis player’s training routine to
achieve peak tennis performance. To
explore the complex nature of de-
celeration, a deterministic model has
been used to showcase the multi-
faceted nature of deceleration and the
many components that need to be
trained to successfully execute the
correct movements. A deterministic
model is a systematic model that
is used to analyze and evaluate an
importantcomponentofaskill,which
provides an approach that is based on
a hierarchy of factors that are de-
pendent on the result or outcome of
the performance (22). Figure 1 de-
scribes a deterministic model for de-
celeration that can help the strength
and conditioning specialist highlight
areas that need to be trained during
the phases of a periodized training
program. At the simplest level of
analysis, deceleration is the fine in-
terplay between musculoskeletal, neu-
ral, and technical components. To
develop effective deceleration capabil-
ities in tennis athletes, it is important
that the strength and conditioning
program includes ample time on all 3
of these broad areas of training.
PLYOMETRIC MOVEMENTS
Plyometric exercises typically are in-
corporated into an athlete’s program
by the strength and conditioning
specialist to improve explosive move-
ments by improving power outputs
(21). Plyometric movements involve an
eccentric loading immediately followed
by a concentric contraction (14).
Plyometric training enhances athletic
performance, typically by improving
power outputs as measured by con-
centric contractions. However, the
benefit of plyometric training also aids
in the training of adaptations in the
sensorimotor system that enhances the
athlete’s ability to brake, sometimes
referred to as the ‘‘restrain mechanism’’
(35,36). In addition, plyometric training
aids in the correction of mechanically
disadvantageous jumping and change
of direction movements. Another added
benefit with respect to deceleration
training is the landing components
after a plyometric type movement.
Because plyometric movements pro-
duce greater power outputs, as the
result of the greater use of stored
potential energy, than nonplyometric
KEY WORDS:
acceleration; deceleration; movement;
quickness; speed; tennis
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58
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movements (33), these greater forces
require greater deceleration abilities.
Therefore, training with the use of plyo-
metric movements not only improves
power and explosive movements but
also results in training adaptations
during the landing or deceleration
phase of these movements. The need
to develop this improved ability to
‘‘brake’’ and improve the restrain mech-
anism will be the major focus of the
remainder of this article.
Figure 1. Deterministic model of deceleration.
Figure 2. Lower body deceleration after a tennis stroke.
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LOWER-BODY DECELERATION
Although training acceleration is vital
to help an athlete become faster, this
improved acceleration ability may
not transfer into improved tennis
performance if the athlete does not
have the ability to decelerate the
faster velocities in the appropriate
time frame and under the needed
control to make optimum contact
with the tennis ball. The ability to
effectively decelerate is also impor-
tant while transitioning into a recov-
ery movement that will allow the
athlete to be in position for the
next stroke in the rally. Figure 2
demonstrates the body position and
importance of appropriate strength,
balance, and coordination, first to
accelerate into the forehand, and
second to decelerate rapidly after
contact with the ball has been made.
An athlete’s ability to decelerate is
a trainable biomotor skill and, as such,
needs to be included in a well-rounded,
tennis-specific training program. An
athlete who can decelerate faster and in
a shorter distance is an athlete who will
not only be faster but will also have
great body control during the tennis
stroke. This greater control during the
stroke will result in a greater level of
dynamic balance (Figures 1 and 4),
which translates into greater power of
the strokes, and more solid racket and
ball contact, which results in more
effective execution. A major influence
on a tennis player’s ability to decelerate
is momentum. Momentum is the
product of the mass of a moving athlete
and his/her velocity. As an athlete’s
velocity increases, momentum is am-
plified, requiring greater forces to de-
celerate the fast moving tennis player.
A larger tennis player (i.e., greater
mass) has a more difficult time de-
celerating and, if the coach focuses the
Figure 4. Four major deceleration components.
Figure 3. Upper and lower body deceleration after a tennis serve.
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Efficient Deceleration
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majority of movement training on
acceleration without focusing ample
time on deceleration, it will result in an
athlete who has a faster initial velocity
but who may not be able to control the
body to slow down fast enough before
and/or after making contact with the
ball. This will result in reduced on-
court performance and may result in
the increased likelihood of injury. It has
been proposed in the literature that the
causes of the majority of athletic
injuries are the result of inappropriate
deceleration abilities of athletes and an
overemphasis of acceleration-focused
(concentric specific movement) exer-
cises both on and off-court (11,26).
UPPER-BODY DECELERATION
In the upper extremity, the body uses
eccentric contractions after ball impact
in virtually all strokes to decelerate the
upper-extremity kinetic chain. These
contractions are of vital importance
around the shoulder and scapular area
because they help to maintain the
critically important stability that is
needed to both prevent injury and
enhance performance. For example,
during the serve (Figure 3), the upper
arm is elevated approximately 90–100
degrees relative to the body (abduc-
tion). In this position, large forces are
generated by the internal rotator
muscles such as the latissimus dorsi
and pectoralis major to accelerate the
arm and racquet head forward toward
an explosive ball impact.
Immediately after ball impact, the
muscles in the back of the shoulder,
including the scapular stabilizers (infra-
spinatus, teres minor, serratus anterior,
trapezius and rhomboids [27]), have to
work eccentrically to decelerate the
arm as it continues to internally rotate.
Fleisig et al. (9) reported anterior
translational forces during the acceler-
ation and follow-through phases of the
overhead throwing motion to approx-
imately 13body weight in the gleno-
humeral joint. The posterior rotator
cuff muscle–tendon units are responsi-
ble for maintaining joint stability by
resisting this anterior translation/dis-
tractional force to prevent injury to the
Figure 5. Deceleration and requirement of eccentric strength during a forehand stroke.
Figure 6. Length–tension curve before and after eccentric exercise. Adapted from
Brughelli and Cronin (3).
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glenoid labrum and other structures in
the shoulder (9). This deceleration is
critical for injury prevention because
the inability to dissipate these large
forces by the muscles in the back of the
shoulder and scapular area can lead to
injury (Figure 3). Similar results are
seen in tennis movements and require
appropriate training (7).
In addition to the high levels of activity
identified during the serve, the same
rotator cuff and scapular muscles work
to decelerate the arm on the forehand
during the follow-through phase.
Training these important muscles pro-
vides important muscle balance to the
tennis player. Players are deficient in
these important decelerator muscles
(5,16,31) and do not understand the
importance of training these muscles
by incorporating deceleration type
training programs into their normal
training regimens.
TRAINING SPECIFICITY
It has been shown in the scientific
literature that linear acceleration and
linear maximum velocity are separate
qualities from multidirectional move-
ments that require a change of
direction and/or a deceleration of
movement (43). Young et al. (43) found
that straight-ahead sprinting, such as
a 100-m sprint in track and field, does
not transfer directly to the movements
typically seen on a tennis court. This
result is caused by the differences in
movement mechanics, muscle firing
patterns, and motor learning skills
required to perform straight line sprint-
ing versus tennis play that require start
and stop movements and numerous
changes of direction in every point. As
a result, training for tennis-specific
acceleration, deceleration, and recov-
ery movements (change of direction)
requires movement patterns, distances,
and energy system focus that resembles
competitive tennis play. Because tennis
is an untimed competition, it may last
anywhere from 30 minutes to 5 hours
(17). However, from a practical stand-
point, we know that high-level com-
petitive tennis has some typical
patterns that occur during matches
Figure 7. 90/90 prone plyometric exercise.
Figure 8. Prone horizontal abduction plyometric exercise.
Figure 9. Reverse catch deceleration training exercise.
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Efficient Deceleration
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that can help the strength and condi-
tioning professional when designing
programs. Athletes typically encounter
between 3 and 7 directional changes
per point, rarely move more than 30
yards in one direction (16,38). In
addition, point length averages are
around 6 seconds, with the majority
of points lasting less than 10 seconds,
and a typical work-to-rest ratio during
individual points and matches is be-
tween 1:2 and 1:5 (15,16,18,19,30). All
these factors can be used to help
develop tennis-specific deceleration
training programs.
WHAT FACTORS IMPROVE A
TENNIS PLAYER’S DECELERATION
ABILITY?
Dynamic balance, eccentric strength,
power, and reactive strength are
4 major qualities that have a significant
influence on an athlete’s ability to
decelerate, while maintaining appro-
priate body position to execute the
necessary tennis stroke and then re-
cover for the next stroke (Figure 4)
(41). Although other components do
contribute to an athlete’s ability to
effectively decelerate, these 4 factors
will be investigated to aid the strength
and conditioning coach in designing
effective programs.
DYNAMIC BALANCE
Dynamic balance is paramount in
tennis, specifically during the deceler-
ation movement phase before or after
the player makes contact with the ball.
Dynamic balance is the ability of the
athlete to maintain a stable center of
gravity while the athlete is moving (1).
This ability to maintain balance in
a dynamic environment allows the
athlete to successfully use the segmen-
tal summation of muscular forces and
movements through the kinetic chain
(13). This efficient energy transfer from
the ground and up through the entire
kinetic chain will result in a more
efficient and powerful tennis stroke, in
addition to faster racket head speeds
and ball velocities. Additionally, dy-
namic balance can refer to the ability
during movements of opposing
muscles to work optimally together
to produce uncompensated movement
patterns (1). This is particularly impor-
tant in the upper extremity when
proper muscle balance must be main-
tained to improve shoulder joint sta-
bility. Although experts may not agree
on the mechanisms involved in athlete-
specific balance, the research suggests
that changes in both sensory and
motor systems influence balance per-
formance (1). The feedback obtained
from plyometric movements encom-
passes a number of reflexive pathways
that aid muscle and neural adaptations
to accommodate unanticipated move-
ments (34). These adaptations are vital
for the prevention of injuries during
practice and competition.
ECCENTRIC STRENGTH
Eccentric strength requires training of
the muscles during the lengthening
phase of the muscle action. An exam-
ple would be during the step before
and the loading phase of a forehand
(Figure 5). Eccentric strengthening
exercises need to be performed both
bilaterally and unilaterally. Nearly all
tennis movements require the athlete
to load one side of the body more than
the other, and it is paramount that
these uneven loading patterns are
trained eccentrically as well as con-
centrically. It is known that physically
trained humans can support approxi-
mately 30% more weight eccentrically
Figure 10. Tennis-specific reverse catch. A) Start. B) Deceleration phase.
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than concentrically (6,23,40). There-
fore, eccentric focused strength train-
ing needs to be incorporated into an
athlete’s periodized program to suc-
cessfully maximize his or her athletic
improvement. A second major benefit
of training eccentric strength is to
aid in the prevention of injuries
(2,26). A large portion of injuries to
tennis players is attributable to in-
sufficient eccentric strength both in
the upper body during the deceleration
of the racket after serves, ground-
strokes, and volleys, as well as in the
lower body during the deceleration of
the body before planting the feet to
establish a stable base for effective
stroke production.
Eccentric strengthening exercises have
a positive effect on altering the length–
tension relationship of muscle (3). The
optimum length of peak tension occurs
at longer lengths, therefore, shifting the
curve to the right (Figure 6).
Length–tension curves for single fibers
(sarcomeres), whole muscle, and single
joints all have different shapes (3). As
the result of these different shapes, it is
vital for the athlete to be trained at a
variety of angles and torques to stimu-
late adaptations in as many muscle
fibers as possible to capture the greatest
effect on altering the length–tension
relationship, specifically during eccen-
tric dominant movements. A great
review of the eccentric exercise litera-
ture by Brughelli and Cronin (3)
devised some tentative conclusions
that should be helpful when designing
programs focused on eccentric
strengthening to optimize the length
tension relationship.
High-intensity and higher volume
eccentric exercise result in greater
shifts in optimum length
Eccentric muscle actions at longer
lengths result in greater shifts in
optimum length
It may be possible to produce a
sustained shift in optimum length
after 4 weeks of eccentric exercise
Excessive muscle damage may not
need to be induced for this shift in
optimum length to occur with
eccentric exercise
From the muscle physiology literature,
we know that after eccentric exercise,
the athlete’s cytoskeletal proteins, such
as desmin and titin, are disrupted and
degradation occurs (10), possibly as
high as 30% after a single bout of
eccentric exercise (37). This process
then results in a protective adaptation
that strengthens the cytoskeletal pro-
teins and prevents them from being
damaged in the future. This is one of
the major theorized mechanisms as to
why eccentric strengthening is impor-
tant for injury prevention, especially
during movements that require rapid
deceleration. Most muscle-related in-
juries occur when they are actively
lengthened (11). From the literature, it
appears that neural control of eccentric
actions is unique from control of con-
centric actions (25). The central nervous
system adjusts motor unit recruitment,
activation level, distribution of that
activation, and afferent feedback dur-
ing eccentric muscle actions (8).
Therefore, specificity of muscle con-
traction mode (i.e., eccentric, isometric
or concentric) during training is
important.
POWER
Power for the tennis player is what
directly translates into greater racket
head speed and ball velocity. Most
forms of plyometric exercise move-
ments are geared toward improving
muscular power. Plyometric exercises
are vital for the development of
great deceleration abilities through
a number of separate, yet interrelated
Figure 11. External rotation at 90 degrees with elastic tubing. A) Start. B) Finish.
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Efficient Deceleration
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mechanisms. Plyometric movements
induce neuromuscular adaptations to
the stretch reflex, as well as the
elasticity of muscle and Golgi tendon
organs (GTOs) (39). The stretch reflex
is initiated during the eccentric loading
and results in greater motor unit
recruitment during the ensuing con-
centric contraction. GTOs have a pro-
tective function against excessive
tensile loads in the muscle; however,
plyometric training results in a degree
of desensitization of the stretch reflex,
which allows the elastic component of
muscle to undergo a greater stretch
(12). The combined adaptations results
in a more powerful concentric con-
traction which, in tennis, would result
in greater power and speed in re-
covering from hitting one stroke to the
next. It is thought that a large portion
of muscular performance gains after
plyometric movements are attributed
to neural changes rather than morpho-
logical (39). This improved neuromus-
cular function directly influences the
major components needed for effective
deceleration ability (Figure 1).
REACTIVE STRENGTH
Reactive strength has been defined as
the ability to quickly change during the
muscle contraction sequence from the
eccentric to the concentric phase in the
stretch–shortening cycle and is a spe-
cific form of muscle power (42). A
plyometric training program that uses
lateral and multidirectional movements
while limiting time on the ground will
develop reactive strength and
Figure 12. Romanian deadlift (RDL). A) Start. B) Finish.
Figure 13. Box jump. A) Start. B) Finish.
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subsequent power outputs in the
muscles and movements that are seen
during tennis play. This type of training
directly relates to a tennis athlete in his
or her recovery sequences between
shots and also during the times in
a point when he or she is ‘‘wrong-
footed’’ and is in need of rapid change
of direction. Increased muscle activity,
specifically in the form of eccentric
loading, will enhance muscle stiffness.
This increase in muscle stiffness leads
to more force absorption in the
muscular–tendon unit rather than
transmitted through the articular struc-
tures (32). It has been suggested that
muscle activation is a dynamic restraint
mechanism that results in protecting
the joints such as the shoulder, hip,
knee, and ankle (32).
PRACTICAL APPLICATIONS FOR
THE TENNIS ATHLETE
Deceleration is a biomotor skill that is
closely linked to agility and multidi-
rectional movement training. As such,
it needs to be trained in a multifocused
training program with appropriate rest
periods and loads that are progressed
based on the tennis player’s growth,
maturation, and training stages. From
a training perspective, the posterior
muscles of the tennis athlete need to be
a focus if the athlete is to become
a successful player who has great
deceleration ability. In the lower body,
the hip extensors, including the glutes
and hamstring muscles, need to be
trained specifically in an eccentric
manner with progressive increases in
resistance. In the upper body, a major
focus needs to be on the posterior
aspect of the shoulder region, which
will assist in the deceleration of the arm
during the tennis serve, groundstrokes,
and volleys. Because limited data are
currently available on deceleration
training guidelines, it is important to
monitor training closely because ec-
centric loading can cause more delayed
onset of muscle soreness than similar
concentric exercise (23). Because mul-
tiple sets of exercises have shown
greater results than single sets (20),
deceleration training should be per-
formed using multiple sets with varied
repetition ranges based on the age,
maturation and training status of the
athletes.
UPPER-BODY EXERCISES
This section contains 5 upper-extremity
plyometric exercises. Each exercise can
be started with a small hand-sized
plyometric ball weighing approxi-
mately 0.5 kg to start with progression
to a 1-kg ball as training progresses and
competency and tolerance to the
exercise is demonstrated by the player.
Exercise 5 (Figure 11) does not use
a weight but rather a piece of elastic
tubing to provide the overload for this
exercise. The plyo dropping exercises
typically use 30-second sets of exercise,
whereas the reverse catching exercises
use multiple sets of 15 to 20 repetitions
to improve local muscular strength and
endurance.
Exercise 1.Exercise 1 shows the 90/90
prone plyometric exercise that places
the shoulder and upper arm in a func-
tional position inherent in the serving
motion. In this exercise, the player
rapidly drops and catches the ball as
quickly as possible, with the ball
moving only a few centimeters as it
leaves the grasp of the player tempo-
rarily before being recaught and drop-
ped from the reference position as
pictured. Typically, multiple sets of 30
seconds are used in training to foster
local muscular endurance (Figure 7).
Exercise 2. Exercise 2 is a prone
horizontal abduction plyometric exer-
cise in which the athlete lies prone on
a supportive surface with the shoulder
abducted 90 degrees with the elbow
extended. A small medicine ball is used
to repeatedly drop and catch the ball as
rapidly as possible as described for
exercise 1 previously. By rotating the
hand such that the thumb is pointing
upward during the dropping and
catching activity (i.e., external shoulder
rotation) this exercise has been found
to increase activation of the rotator cuff
muscles (Figure 8) (24,28).
Exercise 3. Exercise 3 shows a reverse
catch deceleration training exercise. In
this exercise, the arm is again posi-
tioned in 90 degrees of elevation
(abduction) and 90 degrees of elbow
flexion as pictured. A partner stands
just behind the player and throws
a small 0.5- to 1-kg medicine ball
toward the player’s hand (30). Upon
catching the ball, the arm moves into
internal rotation until the forearm is
nearly parallel to the ground, just as it is
decelerated during the serving motion
functionally. The player, after deceler-
ating the ball, rapidly fires the ball
backwards toward the partner, per-
forming a concentric contraction of the
Figure 14. Lateral hurdle runs with hold.
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Efficient Deceleration
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rotator cuff and scapular muscles. Re-
cent research has demonstrated signif-
icant increases in eccentric strength in
the shoulder of subjects when using
these types of exercises in a perfor-
mance enhancement training program
(Figure 9) (4).
Exercise 4. Exercise 4 shows a variation
of the reverse catch exercise where the
athlete keeps the elbow straight during
the catching and subsequent release of
the plyo ball to simulate the serving
motion and a PNF D2 diagonal pattern.
The PNF D2 pattern is a functional
diagonal pattern that closely simulates
the movement pattern the upper ex-
tremity goes through during the throw-
ing or serving motion. D2 extension,
which is performed concentrically in
this exercise, includes the patterns of
shoulder flexion, abduction, and exter-
nal rotation, whereas the eccentric
action incurred in this exercise after
the ‘‘catch’’ of the medicine ball (D2
flexion) includes shoulder extension,
internal rotation, and slight cross arm
adduction. This pattern is chosen for its
activation pattern, which closely simu-
lates the functional throwing or serving
action, as well as its activation of the
rotator cuff and scapular muscles.
Emphasis is initially on the deceleration
of the ball as the arm continues forward
after catching the ball then rapidly
reversing direction to perform an ex-
plosive concentric backward throwing
movement (Figure 10).
Exercise 5. Exercise 5 shows the external
rotation at 90 degrees exercise with
elastic tubing. The traditional way of
doing this exercise involves slow con-
trolled internal and external rotation at
90 degrees of abduction. However, to
increase the eccentric or deceleration
emphasis of this exercise, a plyometric
type format can be incorporated to add
variety. Start with tension on the tubing
with the shoulder elevated 90 degrees in
the scapular plane (30 degrees forward
from the coronal plane) (Figure 11).
The shoulder should be externally
rotated 90 degrees, which places the
forearm in a vertical position. The
athlete then rapidly decelerates for-
ward into internal rotation until the
forearm reaches a horizontal position.
Figure 15. A) MB deceleration catch lunge (linear). B) MB deceleration catch lunge (Lateral). C) MB deceleration catch lunge (45
degrees). D) MB deceleration catch lunge (cross-over).
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Upon reaching this position, the
athlete then explosively returns the
hand and forearm back to the starting
position with as little pause between
the initial lengthening phase of the
exercise and the concentric explosive
phase as possible. This is repeated for
multiple sets of 15 to 20 repetitions
(Figure 11).
LOWER-BODY EXERCISES
Exercise 6.Exercise 6 shows a
Romanian deadlift strength exercise
that works on the muscular develop-
ment of the hamstrings, glutes, and
lower back muscles as force is applied
during eccentric muscle actions. Rep-
etition ranges and time under load for
this exercise should focus on both
muscular strength and endurance dur-
ing the training program (Figure 12).
Exercise 7. Exercise 7 shows a tradi-
tional box jump with specific emphasis
on the landing phase. It is important to
have the athlete land in a strong squat
position, which develops eccentric
strength and rapid deceleration abili-
ties. A more advanced athlete who has
developed appropriate lower body
strength can advance to performing a
depth box jump. However, for younger
athletes, or athletes with limited
strength in the lower body, a depth
jump should only be performed after
appropriate training and lower-body
strengthening exercises (Figure 13).
Exercise 8. Lateral Hurdle Runs with
Hold. This is a traditional lateral-
focused plyometric movement that
works on the muscles of the lower
body, from a stretch shortening per-
spective, but also at the end of each set
of 4 hurdles the athlete needs to
decelerate and come to a complete
stop and hold the lowered center of
mass position for 2 complete seconds
before reaccelerating back into the
exercise (Figure 14).
Exercise 9. Medicine Ball Deceleration
Catch and Lunge (Linear, Lateral, 45
Degrees, and Cross-Over). This exercise
focuses on the athlete catching a rela-
tively heavy medicine ball during the
eccentric portion of the lunge and then
releasing it during the concentric
portion of the lunge. The catching
aspect of the movement loads the
eccentric portion (Figure 15).
Mark Kovacs is
the Manager of
Sport Science for
the United States
Tennis Association.
Paul Roetert is
the Managing Di-
rector of Player
Development for
the United States
Tennis Association.
Todd
S. Ellenbecker
is the National
Director of Clinical
Research–Physio-
therapy Associates
and is the Director
of Sports Medicine
for the ATP Tour.
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Strength and Conditioning Journal | www.nsca-lift.org 69
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... Subsequently, the potential factors underpinning superior horizontal deceleration performance are far less thoroughly understood. While deceleration has previously been described as the "forgotten factor" in sport-specific training [20], more recently, horizontal deceleration has nevertheless been shown to underpin rapid change of direction (COD) manoeuvres in athletes participating in RIMD sports [21][22][23]. Rapid horizontal deceleration ability also enables athletes to reduce momentum during very short time frames and distances to successfully evade or pursue opponents (i.e. to rapidly create and close down spaces) [24,25]. ...
... Previously, although anecdotal, the four major NMP determinants of deceleration were suggested as: (1) eccentric strength, (2) reactive strength, (3) power and (4) dynamic balance [20]. Table 3 provides a summary of studies that have investigated the NMP determinants of deceleration ability, including eccentric, reactive, and concentric strength qualities and RFD. ...
... Reactive strength has previously been proposed to be an important NMP determinant of deceleration ability [20]. However, only one prior study by Harper et al. [78] has investigated the associations between this quality and maximal horizontal deceleration ability using drop jump (DJ) reactive strength index (RSI; jump height/GCT) measured from both 20-cm and 40-cm drop heights. ...
Article
Full-text available
Rapid horizontal accelerations and decelerations are crucial events enabling the changes of velocity and direction integral to sports involving random intermittent multi-directional movements. However, relative to horizontal acceleration, there have been considerably fewer scientific investigations into the biomechanical and neuromuscular demands of horizontal deceleration and the qualities underpinning horizontal deceleration performance. Accordingly, the aims of this review article are to: (1) conduct an evidence-based review of the biomechanical demands of horizontal deceleration and (2) identify biomechanical and neuromuscular performance determinants of horizontal deceleration, with the aim of outlining relevant performance implications for random intermittent multi-directional sports. We highlight that horizontal decelerations have a unique ground reaction force profile, characterised by high-impact peak forces and loading rates. The highest magnitude of these forces occurs during the early stance phase (< 50 ms) and is shown to be up to 2.7 times greater than those seen during the first steps of a maximal horizontal acceleration. As such, inability for either limb to tolerate these forces may result in a diminished ability to brake, subsequently reducing deceleration capacity, and increasing vulnerability to excessive forces that could heighten injury risk and severity of muscle damage. Two factors are highlighted as especially important for enhancing horizontal deceleration ability: (1) braking force control and (2) braking force attenuation. Whilst various eccentric strength qualities have been reported to be important for achieving these purposes, the potential importance of concentric, isometric and reactive strength, in addition to an enhanced technical ability to apply braking force is also highlighted. Last, the review provides recommended research directions to enhance future understanding of horizontal deceleration ability.
... Curiosamente, las deportistas más lentas disminuyeron su velocidad en el test con freno, por lo que sería interesante dilucidar qué procesos ocurren en esta pérdida de rendimiento, para así proponer estrategias de campo para su mejor. en línea similar a lo postulado por Kovacs et al. (2008), se podrían, atender tres ejes básicos de análisis: ...
... Parece ser un factor determinante en las desaceleraciones, tanto la capacidad de aplicar fuerza en el menor tiempo posible (tasa de desarrollo de fuerza) (DosʼSantos et al., 2017;Kovacs et al., 2008), como la velocidad de reacción del sistema neuromuscular en aquellas acciones que implican el ciclo de estiramiento acortamiento (Kovacs et al., 2008). ...
... Parece ser un factor determinante en las desaceleraciones, tanto la capacidad de aplicar fuerza en el menor tiempo posible (tasa de desarrollo de fuerza) (DosʼSantos et al., 2017;Kovacs et al., 2008), como la velocidad de reacción del sistema neuromuscular en aquellas acciones que implican el ciclo de estiramiento acortamiento (Kovacs et al., 2008). ...
Article
Full-text available
Objetivo: relacionar la capacidad de frenado, aceleración y los niveles de fuerza aplicados en saltos con vector vertical y horizontal. Método: se evaluaron 12 jugadoras de hockey (21,84, ± 6,81 años) de primera división, registrándose la velocidad máxima de carrera lineal en 17 metros (17m), y en misma distancia, pero con un frenado final en un espacio de 50 centímetros (17mFr). También se aplicó un test de resistencia (30-15 IFT40m) y dos de salto: uno de vector vertical (CMJ) y otro horizontal (HJb). Se utilizó tecnología de GPS, fotocélulas, alfombra de salto y odómetro. Resultados: las jugadoras corrieron los 17mFr, 0,9 ± 1,8% más lento en los 17m (r = 0,85). Distinguiendo entre veloces y lentas, calculando la mediana del tiempo en los 17m (<3"), se observó una correlación más alta en veloces (n = 6; r = 0,91) que en lentas (n =6; r = 0,62). A su vez, las jugadoras veloces correlacionaron mejor en el HJb que las lentas (r =-0,70 vs-0,58), lo que se invirtió en el CMJ (r =-0,19 vs.-0,82). Conclusión: los datos evidencian que las deportistas más rápidas tienden a mantener velocidades similares a su máximo, aun cuando saben que deben frenar en un espacio limitado y aplican fuerza en el vector horizontal mejor que las más lentas, quienes son superiores en el vector vertical. Palabras clave: aceleración, desaceleración, fuerza muscular, saltabilidad, velocidad. Objective: to relate the braking capacity, acceleration and the levels of force applied in jumps with vertical and horizontal vector. Method: 12 first division female hockey players (21.84, ± 6.81 years) were evaluated, registering the maximum linear running speed in 17 meters (17m), and in the same distance but with a final braking in a space of 50 centimeters (17mFr). A resistance test (30-15 IFT40m) and two jumping tests were also applied: one with a vertical vector (CMJ) and another horizontal (HJb). GPS technology, photocells, jump mat and odometer were used. Results: the players ran the 17mFr, 0.9 ± 1.8% slower in the 17m (r = 0.85). Distinguishing between fast and slow, calculating the median time in the 17m (<3"), a higher correlation was observed in fast (n = 6; r = 0.91) than in slow (n = 6; r = 0, 62). In turn, the fast players correlated better in the HJb than the slow ones (r = -0.70 vs. -0.58), which was reversed in the CMJ (r = -0.19 vs. -0.82). Conclusion: the data show that the fastest athletes tend to maintain speeds similar to their maximum, even when they know that they must brake in a limited space and apply force in the horizontal vector better than the slower ones, who are higher in the vertical vector.
... In this regard, persuasive evidence from cross-sectional works indicated moderateto-large associations between eccentric muscle strength and CoD performance [47,[54][55][56][57]. Jones, et al. [58] examined the impact of the eccentric muscle strength of the knee extensors in female soccer players aged 22 years. ...
Article
Full-text available
Objective: This study aimed to systematically review and meta-analyze the effect of flywheel resistance training (FRT) versus traditional resistance training (TRT) on change of direction (CoD) performance in male athletes. Methods: Five databases were screened up to December 2021. Results: Seven studies were included. The results indicated a significantly larger effect of FRT compared with TRT (standardized mean difference [SMD] = 0.64). A within-group comparison indicated a significant large effect of FRT on CoD performance (SMD = 1.63). For TRT, a significant moderate effect was observed (SMD = 0.62). FRT of ≤2 sessions/week resulted in a significant large effect (SMD = 1.33), whereas no significant effect was noted for >2 sessions/week. Additionally, a significant large effect of ≤12 FRT sessions (SMD = 1.83) was observed, with no effect of >12 sessions. Regarding TRT, no significant effects of any of the training factors were detected (p > 0.05). Conclusions: FRT appears to be more effective than TRT in improving CoD performance in male athletes. Independently computed single training factor analyses for FRT indicated that ≤2 sessions/week resulted in a larger effect on CoD performance than >2 sessions/week. Additionally, a total of ≤12 FRT sessions induced a larger effect than >12 training sessions. Practitioners in sports, in which accelerative and decelerative actions occur in quick succession to change direction, should regularly implement FRT.
... An eccentric muscle action occurs when the distance between the origin and insertion of the muscle is increased (i.e., the muscle is lengthened), while force is developed within the muscle (2). It has been proposed that an athlete requires a sufficient amount of eccentric muscular strength during the deceleration/braking phase to reduce momentum to allow rapid COD movements to occur (7,27,39). This is further supported by empirical findings that show significant relationships (r 5 20.53 to 20.89) between eccentric muscle strength and COD performance (25,26,39,40). ...
Article
Full-text available
Change of direction (COD) ability is considered essential for successful participation in many field and court sports. Several COD models that currently exist identify technique, leg strength qualities, and straight sprint speed as the key determinants of COD performance. This narrative review discusses the original COD model, focusing on specific leg strength qualities (concentric, eccentric, iso-metric, and reactive strength) and their relationship with 5-0-5 COD performance. It is clear from the existing literature that each of these leg strength qualities contributes to the performance of the 5-0-5 COD test; however , it is unclear which are most at play during the phases of performing a COD. This review introduces a new COD model and a way to split the modified 5-0-5 COD test into 4 distinct phases (acceleration, deceleration , 180 B turn, and reacceleration). This new perspective and proposed method of testing provides greater diagnostic value to the modified 5-0-5 COD test and allows coaches and practitioners to be more targeted with feedback and programming to improve COD and sporting performance.
... Comparing to the acceleration, the objective of deceleration is to absorb negative work by lower limb to reduce the velocity. Kovacs et al., (2015) has been suggested that 4 major physical qualities exert a significant influence on deceleration ability, 33 namely, dynamic balance, eccentric strength, power, and reactive strength (Kovacs, Roetert et al. 2008). That is to see, three components are related to strength performance, which indicating the important role of the lower limb strength for deceleration performance. ...
Thesis
The main objective of this thesis was to determine the influence of hamstring and quadriceps neuromuscular capacities on explosive performance and the risk of lower limb injuries in soccer players. The first study of this thesis examined the relationship between the isokinetic force capacity of the knee muscles and the deceleration performance in professional female soccer players. The results revealed the importance of the eccentric force of the knee extensors contributing to the production of braking force during the linear deceleration test. The second study of this thesis was interested in the influence of the direction of jump on the dynamic postural stability during an unipodal landing and the importance of the hamstring / quadriceps co-activation in the stabilization capacity of the legs unipodal supports. The main finding is that the dominant leg showed better dynamic postural stability during the jump landing, associated with higher H / Q co-activation in the first milliseconds of the contact phase. The third study of this thesis explores the influence of fatigue generated by maximal isokinetic contractions on the capacity for rapid strength of the hamstrings and quadriceps in footballers. The results showed that the functional and conventional ratios measured during the preseason testing are not sensitive to fatigue. In contrast, the rapid hamstring / quadriceps torque ratio is more affected by fatigue. In summary, this work has shown that the evaluation of the explosive strength and fatigability capacities of the extensor and flexor muscles of the knee on an isokinetic ergometer remains a central subject for the improvement of explosive performance and the reduction of the risk of injury in the soccer player and footballer. In addition, the results of this work show the value of systematically associating the analysis of the EMG signal with the evaluation of the isokinetic force capacities, sprint performance and stability of the supports in male and female soccer players.
... Scientific research shows that within multi-directional sprint movements, such as CoDs, athletes must maintain a certain degree of stability and balance during the transition from a dynamic state, deceleration, to a momentarily static, stop, to change direction, transfer of muscle impulses, before returning to another dynamic, acceleration. An optimal dynamic equilibrium would help to maintain a stable centre of gravity allowing a better optimization of the action times in the type of movement described (Bressel E. et al., 2007;Kovacs et al., 2008). Many studies have also reported that, imbalances in strength and power qualities can be detrimental to athletic performance (Bailey et al., 2013;Hart et al., 2014, Bazyler et al., 2014, Bailey et al, 2015). ...
Article
Full-text available
Scientific research shows that during multi-directional sprints, athletes must maintain a certain degree of stability and balance during the transition from a dynamic state, to a momentarily static state to change direction, before returning to another dynamic, acceleration. An optimal dynamic balance would help to maintain a stable centre of gravity, allowing better optimization of the action times in the technical execution of the performed gesture. The role of body imbalances and their effect on the performance of linear and multi-directional acceleration will require further significant studies, especially related to the muscular and articular biomechanics of the gestures, to better clarify the personalization of performance in the different executive speeds, to establish the different commitment on the osteo-muscular system. The main aim of this study arises from the idea that a symmetrization of the sides of the body, will certainly benefit the dynamics in question. The aim is to identify the elements of symmetry of the human body and how it can be performative, in a general sense, thanks to the use of inertial sensors (IMU), which allow to obtain extremely high precision data on which to calibrate the training and performance work parameters. Data collection was performed using latest generation IMU sensors worn by the subjects using special undershirts. The research protocol was carried out on 104 young football players (average age 11.7). Two tests were performed, the first was carried out during the summer preparation (preseason, T1), the second was at the end of the football season (postseason, T2). The parameters under attention were: Training load, AVG Strength and Lateral Imbalance. The results of the comparison of the two tests were: for Training Load, 74 players (71.16%) showed a decrease and 28 an increase (26.92%) and 2 a zero variation (1.92%); for Average strength, 52 players (50%) had a decrease and 49 an increase (47.12%) and 3 a zero change (2.88%) and for Imbalance, 46 players (44.23%) showed a decrease and 58 an increase (55.77%).These three parameters, are respectively expression of force, force distribution and dynamic body imbalance provide data on the real abilities useful for optimal performance in changes of direction for each of the items investigated and therefore, they give the possibility to create more specifically adequate training programs.
... (DosʼSantos, T., et al., 2017;Kovacs, M.S., et al., 2008). Pero también el nivel de fuerza excéntrica de los grupos musculares dominantes en la desaceleración (Harper, D.J, et al., 2021;Hewit et al., 2011;Griffith, M., 2005), así como cierto grado de fuerza de base para el control del cuerpo y hasta un óptimo ajuste mecánico entre las acciones musculares concéntricas y excéntricas. ...
Conference Paper
Full-text available
En el presente texto se intenta primeramente exponer los errores conceptuales históricos que llevan a los entrenadores, a incorrectas propuestas en el campo de los trabajos “pliométricos”. En segundo lugar con base en el conocimiento científico actual, incluso con evidencia en resultados preliminareses de nuestro trabajo de investigación, se postulan tres posibles aspectos a considerar como factores determinantes de las acciones pliométricas de desaceleración y frenado, en los deportes sociomotrices de oposición-colaboración. Finalmente se intenta brindan una guia de referencia general para el entrenamiento de la pliometría en un continuo que va desde el ciclo de estiramiento acortamiento, hasta la amortiguación o frenado.
... The primary muscles used to decelerate in running actions are the quadriceps and gastrocnemius, working through eccentric muscle actions to absorb and disperse the impact forces, which can be very high if the time available to absorb them is limited (Hewit et al., 2011). It has been proposed that strength and power play an important role in decelerating, involving the muscular stretch-shortening cycle (SSC) (Harper et al., 2018;Kovacs et al., 2008). ...
Article
Full-text available
Post-Activation Potentiation (PAP) is a phenomenon which can improve power performance executed after a previous conditioning activity. PAP is usually evoked through heavy resistance or plyometric exercise. It has been suggested to refer to as Postactivation Performance Enhancement (PAPE) when research is field-based on explosive activities. To our best knowledge, no studies have investigated the effects of PAPE on deceleration performance, which is a key factor in sports involving change of directions. Therefore, the aim of this study was to investigate the influence of a plyometric exercise protocol on a subsequent deceleration running performance. University soccer players (n = 18) performed seven deceleration trials and were assessed at baseline and after ~15 s, 2, 4, 8, 12 and 16 min either following a walking control condition (C) or three sets of ten repetitions of alternate-leg bounding (plyometric, P). Results showed no significant differences at any of the trials under the control condition (C) in comparison to the relative baseline. Under the plyometric condition (P), deceleration performance executed two minutes after the plyometric activity resulted in significantly faster results compared to the baseline values (p = 0.042; ES = 0.86, large effect; % of improvement = 4.13 %). The main findings are that plyometric exercise improves a subsequent running deceleration performance, 2 min after its execution. Future investigations should focus on more complex actions such as changes of direction and agility.
Article
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Background The ability to perform a quick and rapid change of direction (CoD) is an important determinant of success in a variety of sports. Previous studies have already highlighted that eccentric strength is a dominant predictor of CoD. However, these studies evaluated eccentric strength through a limited number of outcome measures and used small sample sizes. Methods A total of 196 athletes participated in the study . The aim of our study was to investigate: (1) the correlation between eccentric outcome measures derived from different tests (Nordic hamstring exercise (NHE), countermovement jump (CMJ) and flywheel (FW) squats), (2) the association between eccentric outcome measures and CoD 90°, CoD 180°; and (3) proportion of explained variance in CoD performance. Results Very large associations ( r = 0.783, p < 0.001) were observed between peak torque during NHE (NHE PT ) and force impulse during the eccentric phase of CMJ (CMJ FI ). Small to moderate correlations were calculated between peak eccentric force in flywheel squats and peak eccentric force in CMJ ( r = 0.220–035, p < 0002). All eccentric CMJ outcome measures and NHE PT were reported as moderate negative associations with both CoD tests. Eccentric measures explained 25.1% of the variance in CoD 90° (CMJ PF , NHE PT , F 0.125 –peak eccentric force during FW squats with 0.125 kg m ² load), while the same outcome measures explained 37.4% of the variance for CoD 180°. Conclusion Our results suggest that different measures of eccentric strength specifically contribute to CoD performance. Therefore, for successful CoD performance, different aspects of eccentric strength training should be considered in testing and training (maximal eccentric strength, eccentric-concentric actions with fast execution).
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Objective: To determine whether functional training reduces the incidence of shoulder pain and increases strength in intercollegiate swimmers. Design: Pretest-posttest. Setting: Laboratory and weight room. Participants: 26 intercollegiate swimmers (13 men, 13 women). Intervention: 6-wk functional training program. Main Outcome Measures: Incidence of shoulder pain was recorded throughout the study. Isokinetic shoulder strength was assessed before and after training. Results: A t test showed significant differences (P < .05) for the incidence of shoulder pain between the experimental (mean episodes = 1.8 ± 2.1) and control (mean episodes = 4.6 ± 4.7) groups. ANOVA with repeated measures revealed no significant strength differences between groups but exhibited significant within-group increases. Conclusions: Incorporating functional exercises might reduce incidence of shoulder pain in swimmers. The results also validate the need to modify preventive programs as the demands of the sport change throughout the season.
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The game of tennis has evolved from the wooden-racket era of long, crafty points based on style and finesse, to the current fast paced, explosive sport based on power, strength and speed, where 210 km/h serves are common. This evolution over the last 20 years has led to an increased interest in tennis research. Competitive tennis athletes need a mixture of anaerobic skills, such as speed, agility and power, combined with high aerobic capabilities. The work-to-rest ratios of competitive tennis athletes range between 1: 3 and 1: 5, and fatigue has been shown to greatly reduce the hitting accuracy. Competitive male tennis athletes maintain body fat <12% and have maximal oxygen uptake values >50 mL/kg/min, and as high as 70 mL/kg/min. Results from lactate testing in tennis players are inconclusive as some studies have shown increased levels, whilst other studies have shown little or no change. Further investigation is required to determine the production and utilisation effects of lactate from playing tennis. The average length of time to play a point in tennis is <10 seconds and this has declined substantially in the last 20 years. Further research is needed to investigate tournament performance and its effect on fatigue, recovery, hormonal and injury levels. As the game of tennis continues to change, the physiological parameters must be continually investigated to help provide athletes, coaches and trainers with information that will aid in the development of efficient and productive tennis performance and injury prevention programmes.
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Twenty-two male and female college varsity tennis players trained for 6 weeks, one group using eccentric isokinetic internal and external shoulder rotation, and the second group using concentric isokinetic internal and external shoulder rotation. Subjects pretested and posttested both concentrically and eccentrically, so that training overflow and specificity could be examined. Three maximally hit tennis serves made before and after training, which were analyzed by high speed cin ematography to obtain ball velocity, served as a func tional performance measurement. Statistical analysis of peak torque (newton meters) and peak torque to body weight ratio have revealed significant concentric strength gains (P < 0.005) in the concentric as well as the eccentric training groups. Eccentric strength gains were demonstrated by the concentric training group at selected speeds (P < 0.05 and P < 0.005) but were not generated in the eccentric group at the P < 0.05 significance level. Functional test analysis shows an increase in maximal serve velocity at a significance level of P < 0.005 in the concentric training group, with no significant (P > 0.01) increases in the eccentric group.
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This study longitudinally examined shoulder internal rotation (IR), external rotation (ER), and total rotation (TROT) in the dominant (D) and nondominant (ND) arms of 44 nationally ranked junior tennis players aged 14-17 years. Analyses conducted across the 4 age groups revealed a significant main effect of age for IR ranges of motion (ROMs; p < 0.05) but not for ER ROMs. Follow-up analyses on D, IR ROMs revealed a significant increase between age 14 and both ages 15 and 16 (p < 0.05) and revealed a slight decrease at age 17. Follow-up analyses for ND, IR ROMs showed no significant difference between ages 14 and 15 but showed a significant difference between age 14 and both ages 16 and 17 (p < 0.05). An additional analysis conducted on TROT revealed a significant main effect of age for ND ROMs (p < 0.05) but not for D ROMs. The results suggest a significant increase in ND, TROT ROMs between ages 14 and 16 that subsequently remains stable.
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