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Biomechanics of the
Tennis Groundstrokes:
Implications for Strength
Training
E. Paul Roetert, PhD,
1
Mark Kovacs, PhD, CSCS,
1
Duane Knudson, PhD,
2
and Jack L. Groppel, PhD
3
1
United States Tennis Association, Boca Raton, Florida;
2
Department of Health and Human Performance,
San Marcos, Texas; and
3
Human Performance Institute, Lake Nona, Florida
SUMMARY
THE PURPOSE OF THIS ARTICLE
WAS TO SUMMARIZE RECENT RE-
SEARCH RELATED TO THE BIO-
MECHANICS OF TENNIS
TECHNIQUE IN GROUNDSTROKES
AND THEN TO RECOMMEND SPE-
CIFIC STRENGTH AND CONDI-
TIONING EXERCISES THAT WOULD
TEND TO IMPROVE TENNIS PER-
FORMANCE AND PREVENT INJURY.
BASED ON THE AVAILABLE
RESEARCH, IT WAS DETERMINED
THAT TRAINING EXERCISES
SHOULD EMULATE THE SEQUEN-
TIAL COORDINATION INVOLVED IN
GROUND STROKE PRODUCTION,
AS WELL AS STABILIZING MUS-
CULATURE THAT MIGHT BE IN-
VOLVED IN DEVELOPING FORCE
OR IN PROTECTING BODY PARTS
FROM STRESSFUL ACTIONS. SPE-
CIFIC EXERCISES BASED ON THE
FINDINGS IN THE RESEARCH LIT-
ERATURE WERE THEN OFFERED.
INTRODUCTION
The game of tennis has changed
dramatically in the past 30
years. This is probably most
evident in groundstroke technique
and strategy. Modern players often
hit aggressive high-speed ground-
strokes to overpower their opponent.
This strategy places extra stress on the
player’s body that strength and condi-
tioning professionals should consider
in designing training programs. This
article will summarize recent research
related to the biomechanics of tennis
technique and propose specific condi-
tioning exercises that logically would
tend to improve performance and re-
duce the risk of injury in tennis.
CHANGES IN TECHNIQUE
Traditional tennis groundstrokes were
hit from a square or closed stance with
a long flowing stroke using simulta-
neous coordination of the body. The
modern forehand and even the back-
hand (particularly the 2-handed back-
hand) are more often hit from an open
stance using sequential coordination of
the body. Elite tennis always had these
2 styles of groundstrokes (1), but since
that time, there has been a reversal
from primarily simultaneous to sequen-
tial groundstroke technique. This
change in the coordinated use of the
‘‘kinetic chain’’ suggests that the load-
ing and injury risk to major segments
of the body may have changed in
tennis (11).
It is not possible to uniquely track the
transfer of mechanical energy in a 3-
dimensional movement of the human
body, but it is generally accepted that
most of the energy or force used to
accelerate a tennis racket is transferred
to the arm and racket from the larger
muscle groups in the legs and trunk
(5,15,21). While it is believed that
optimal use of the kinetic chain will
maximize performance and reduce the
risk of injury (6,11), the transfer of force
and energy to the small segments and
tissues of the upper extremity do place
them under great stress. For example,
medial elbow pain is on the rise in
tennis players most likely because of
the transfer of energy from the legs
and trunk in forehands and serves. This
focuses stress on the medial elbow
region in the bent-arm sequential co-
ordination in these strokes. The next
sections will summarize recent re-
search on technique issues specific to
each groundstroke that are important
to consider when planning condition-
ing programs. Several reviews of the
biomechanics of tennis are available for
interested readers (5,15,18).
FOREHAND
Vigorous extension of the lower ex-
tremity in classic closed stance fore-
hands creates greater axial torques to
rotate the pelvis and hips than not
using the legs (9). While this transfer of
energy has not been tested in open
KEY WORDS:
kinetic chain; tennis-specific training;
technique analysis
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stance forehands, it is logical that
vigorous leg drive also transfers
energy to trunk rotation. Knudson
and Bahamonde (16) reported non-
significant differences in racket path
and speed at impact between open and
square stance forehands of tennis
teaching professionals. As stated by
Roetert and Reid (20), there are 2
things to remember related to these
forehand stances: (a) open stances are
often situation specific and (b) both
stances use linear and angular momen-
tum to power the stroke. Situation-
specific forehands refer to the need to
produce different types of forehands
depending on where the player is in the
court, the purpose of the shot (tactics),
amount of preparation time available,
as well as where the opponent is during
the same scenario. Tennis players need
to create differing amounts of force,
spin, and ball trajectories from a variety
of positions, and this has resulted in
adaptations of stroke mechanics and
stances. The most common situations
where open stance forehands are
applied include wide and deep balls
when the player is behind the baseline
or requires greater leverage to produce
the stroke.
Vigorous axial hip and upper-trunk
rotation allow for energy transfer from
the lower extremity to the upper
extremity in the square stance fore-
hand. The upper trunk tends to
counter-rotate about 90 to 100°from
parallel to the baseline and about 30°
beyond the hip in the transverse plane
(22) in preparation for the stroke.
Forward axial torque to rotate the hips
achieves its peak at the initiation of
the forward stroke (8). Forward rota-
tion of the upper trunk coincides with
a lag in the upper extremity resisted by
eccentric muscle actions and large peak
shoulder horizontal adductor and
internal rotation torques (3). Well-
coordinated sequential rotations up
the kinetic chain through the trunk
and upper extremity take advantage of
the stretch-shortening cycle of muscle
actions.
The forearm flexors and grip muscula-
ture are also important in the tennis
forehand. Not because these muscles
create a great deal of joint rotation to
accelerate the racket (4) or because
grip forces increase ball impulse (13),
but because the energy from the lower
body and trunk must be transferred to
the racket in the later stages of the
stroke. In fact, the preferred style of
grip and height of the ball at impact
used by the player significantly affects
the potential contribution of the
hand/wrist rotation to racket speed
(4). The main kinetic chain motions
that create racket speed in the fore-
hand are trunk rotation, horizontal
shoulder adduction, and internal rota-
tion (4). Modern forehand technique
(typically utilizing grips ranging be-
tween eastern and western grips)
clearly involves sequential coordina-
tion that takes advantage of stretch-
shortening cycle muscle actions.
Training exercises should, therefore,
emulate this sequential coordination,
as well as stabilizing musculature.
Following impact in all tennis strokes,
the racket and arm retain the vast
majority of the kinetic energy from
before impact, so the eccentric
strength of the musculature active in
the follow-through should also be
trained. Eccentric strength both in
the upper and in the lower body can
assist in maximizing tennis perfor-
mance as well as to aid in the pre-
vention of injuries (12). Particularly, the
catching phase of the medicine ball
(MB) tosses in Figures 4–7 helps in
improving both upper- and lower-
body eccentric strength.
Figure 1a–c show the preparation
phase of the open stance forehand.
The player’s weight transfer from his
right leg to his left leg (he is left
handed) shows the horizontal linear
momentum used to preload the left leg
for a stretch-shortening cycle action to
initiate the stroke. Some of the energy
stored in this leg is converted to
predominantly upward (vertical linear)
momentum but also forward (horizon-
tal linear) momentum. This leg drive
utilizes ground reaction forces and is
critical for linear to angular momentum
transfer and the development of high
racket speed. In Figure 1d–f, we can see
the forward swing. The pronounced
hip and shoulder rotation from Figure
1c–f is evidence of the use of angular
momentum. Energy from the left leg
is transferred as the hips open up first,
followed by the shoulders. The com-
pletion of the swing shows a follow-
through in the direction of the target
until well after contact is made fol-
lowed by the racket swinging back
over the head as a result of the forceful
rotational component of the swing.
This follow-through, where the racket
actually finishes over the head, is an
adaptation that many players have
implemented, and although the follow-
through is initially still toward the
target (Figure 1e), the overall pathway
of the stroke (Figure 1f) ending up
over the shoulder allows the player
to impart greater spin on the ball.
This adaptation is partially the result
of technology changes in the tennis
racket and strings allowing for more
power and spin generation resulting
in more margins for error on the
strokes.
ONE-HANDED AND TWO-HANDED
BACKHAND
Training the wrist extensors is partic-
ularly important for tennis players
using a 1-handed backhand. Torques
about the wrist in 1-handed backhands
are greater than direct force loading
(14) and can create a rapid stretch of
the wrist extensors that is more pro-
nounced in players with a history of
tennis elbow (17). This is strong
retrospective evidence that training
of the wrist extensors and grip may
be useful to reduce the risk of the
common overuse injury of the lateral
epicondyle.
There are differences in the use of the
legs, trunk, and upper extremity be-
tween the 1- and 2-handed backhands.
One-handed backhands have the hit-
ting shoulder in front of the body and
rely less on trunk rotation and more
on coordinated shoulder and forearm
rotations to create the stroke (Figure
2a–f). Front-leg extensor torques are
larger in the 1-handed backhand
than the 2-handed backhand (19).
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Biomechanics of the Tennis Groundstrokes
Two-handed backhands have larger
extension torques in the rear leg, which
result in larger axial torques to rotate
the hips and trunk than 1-handed
backhands (2,10,19). Greater upper-
trunk rotation has been observed in
2-handed backhands than in 1-handed
backhands (19). Note the hip and trunk
rotation in the 2-handed backhand
(Figure 3a–f).
Despite these differences, skilled play-
ers can create similar levels of racket
speed at impact in 1- and 2-handed
backhands (19). In general, there are
2 styles of coordination in 2-handed
backhands. One essentially involves
straight arms and 4 major kinetic chain
elements (hips, trunk, shoulder, and
wrist), while the other adds rotations
at the elbow joints (7,19). Whatever
the technique adopted, the strength
and conditioning professional should
work with the tennis coach to custom-
ize training programs for the specific
techniques used by players.
EXERCISES
Examples are described for forehands
(right-handed players), but they should
also be performed on the opposing
side to mimic movements required for
backhand strokes.
MEDICINE BALL DEEP
GROUNDSTROKE
The purpose was to train the athlete to
move efficiently to deep balls behind the
baseline and to be able to produce
greater energy transfer from open
stance position that will translate into
greater weight transfer, trunk rotation,
and more effective stroke production
from deep in the court (Figure 4).
The athlete starts on the center service
mark and the coach/trainer throws the
MB about 3 to 5 feet behind and to the
right. The athlete will need to move
back and across quickly to catch the
MB (loading phase) and then while
maintaining dynamic balance produce
a forceful hip turn and throw that will
mimic the muscle contractions and
movements required for a deep de-
fensive forehand stroke (for a right-
hander).
Figure 1. (a–f ) Forehand groundstroke—(a–c) illustrates the preparation phase of the open stance forehand, while (d–f ) illustrates
the forward swing.
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MEDICINE BALL SHORT
GROUNDSTROKE
The purpose was to train the athlete to
move forward and in a balanced fash-
ion transfer energy from the lower
extremities (open or square stance) to
weight transfer and hip/trunk rotation
for more effective stroke production
(Figure 5). In Figure 5, the athlete is
demonstrating a closed stance catching
position. This movement can also be
performed using an open stance catch-
ing position.
The athlete starts on the center service
line and the coach/trainer throws
the MB about 3 to 5 feet in front and
to the athlete’s right. The athlete will
need to move forward and across
quickly to catch the MB (loading
phase) and then while maintaining
dynamic balance produce a forceful
hip and trunk rotation to throw the
MB. This will mimic the movement
and muscles used during a short at-
tacking forehand.
MEDICINE BALL WIDE
The purpose was to train the athlete
to move sideways and to be able to
produce greater energy transfer from
an open stance position (Figure 6).
This position will produce greater
weight transfer, trunk rotation, and
more effective stroke production on
wide balls.
The athlete starts on the center
service line and the coach/trainer
throws the MB about 5 feet to the
right of the athlete. The athlete will
need to move laterally (utilizing either
the shuffle or the crossover step) to
catch the MB (loading phase) and then
while maintaining dynamic balance
produce a forceful hip and trunk
rotation to throw the MB. This
movement sequence will mimic the
movement and muscles used in a wide
forehand.
MEDICINE BALL WALL OPEN
STANCE
The purpose was to develop rotational
hip and core strength in movement
Figure 2. (a–f) One-handed backhand groundstroke—(a–c) illustrates the preparation phase of a 1-handed closed stance backhand,
while (d–f) illustrates the forward swing.
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Biomechanics of the Tennis Groundstrokes
patterns and planes that are most used
during tennis strokes (Figure 7).
The athlete starts about 5 to 8 feet
from a solid wall and loads the hips
and core while also putting the
oblique muscles on stretch. From
this loading position (Figure 7 demon-
strates an open stance loading
position), the athlete forcefully
rotates the hip and upper body to
release the MB as hard as possible
against the wall.
Figure 3. (a–f). Two-handed backhand groundstroke—(a–c) illustrates the preparation phase of a 2-handed open stance backhand,
while (d–f) illustrates the forward swing.
Figure 4. Medicine ball deep groundstroke drill.
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CABLE ROTATION IN THE
TRANSVERSE PLANE
The purpose was to develop rotational
core strength in the transverse plane
(Figure 8).
The athlete grasps the handle of a cable
pulley machine at the height of the
waist. The athlete takes 3 to 5 steps
from the machine to increase the
tension and lowers the body into
a quarter squat position. From this
position, the athlete slowly rotates
through the transverse plane as far as
the athlete’s flexibility allows. This
movement is then repeated on the
way back to the starting position
focused on developing deceleration
ability in this same plane of motion.
WRIST ROLLER
The purpose was to increase grip
strength and endurance via forearm
flexion and extension (Figure 9).
The athlete grasps the wrist roller
device with both hands at shoulder
height. The athlete flexes and extends
the wrist to lower the weight. Once the
weight is lowered as far as possible,
the athlete then flexes and extends the
wrist to lift the weight back up to the
starting position.
WEIGHTED FOREARM
PRONATION AND SUPINATION
The purpose was to develop forearm
strength and endurance in pronation
and supination (Figures 10).
Figure 5. Medicine ball short groundstroke drill.
Figure 6. Medicine ball wide groundstroke drill.
Figure 7. Medicine ball wall open stance groundstroke drill.
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Biomechanics of the Tennis Groundstrokes
The athlete places their forearm
on a table or bench while grasping
a head heavy instrument (a weighted
bar and hammer are both good
options). Figure 10a demonstrates
a forearm pronation movement, and
Figure 10b demonstrates a forearm
supination movement. Both these
movements are used during tennis
groundstrokes.
SUMMARY AND APPLICATIONS
FOR COACHES
The purpose of this article was to help
coaches recognize the unique aspects
of tennis groundstrokes, with specific
implication for how they can train their
athletes. Again, the 2-fold approach of
this article was to help practitioners
realize the types of training that will (a)
improve performance by creating more
force within muscle groups, improve
coordination between various body
parts involved in each stroke, and
develop overall power in the athlete’s
stroke production and (b) develop
strength in the various body parts
and across joints that would protect
the athlete from injury.
Practical exercises have been offered
that will emulate the stroke coordina-
tion to improve the efficiency of stroke
production as well as exercises that will
improve the athlete’s ability to deceler-
ate specific body parts to assist in
recovery after the execution of the
specific stroke. The exercises denoted
in this article are designed to help the
coach with on-court and off-court
training so that various training sites
can be utilized for effectiveness in
training. For example, MB drills are
offered to help the athlete, not only
move and get in position properly but
Figure 8. Cable rotation (in the transverse plane) drill.
Figure 9. Wrist roller drill.
Strength and Conditioning Journal | www.nsca-lift.org 7
also to execute the form of the stroke in
the proper pattern. Coordination of
body weighttransfer is discussed as well.
Finally, there is a demonstration of
how the legs, hips, and torso should
move in synchrony as well as in-
struction on how to develop coordi-
nation so the athlete can utilize the
kinetic chain more effectively. It is
anticipated that coaches will be able to
provide a safer yet more productive
and effective strength training regimen
for their athletes.
E. Paul
Roetert is
Managing
Director of
Coaching
Education and
Sport Science at
the United States
Tennis Association.
Mark Kovacs is
Senior Manager
of Strength and
Conditioning/
Sport Science
at the United
States Tennis
Association.
Duane
Knudson is
Chair of the
department of
Health and
Human
Performance at
Texas State
University.
Jack Groppel is
co-founder of the
Human
Performance
Institute.
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