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Chủ đề chính: Groundstroke, Backhand
Tóm tắt nội dung (trích từ tài liệu gốc): �Journal of Sports Science and Medicine (2015) 14, 194-202 http://www.jssm.org Review article Performance Factors Related to the Different Tennis Backhand Groundstrokes: A Review Cyril Genevois 1, Machar Reid 2, Isabelle Rogowski 1 and Miguel Crespo 3 1 Centre de Recherche et d'Innovation sur le Sport, Universit� de Lyon, Villeurbanne Cedex, France; 2 Tennis Australia 3International Tennis Federation Abstract With this in mind, Pubmed, Google Scholar and The backhand is one of the two basic groundstrokes in tennis Science Direct were searched for two keywords: tennis and can be played both wit
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�Journal of Sports Science and Medicine (2015) 14, 194-202
http://www.jssm.org
Review article
Performance Factors Related to the Different Tennis Backhand Groundstrokes:
A Review
Cyril Genevois 1, Machar Reid 2, Isabelle Rogowski 1 and Miguel Crespo 3
1 Centre de Recherche et d'Innovation sur le Sport, Universit� de Lyon, Villeurbanne Cedex, France; 2 Tennis Australia
3International Tennis Federation
Abstract With this in mind, Pubmed, Google Scholar and
The backhand is one of the two basic groundstrokes in tennis Science Direct were searched for two keywords: tennis
and can be played both with one or two hands, with topspin or and, backhand, which were in turn combined via Boolean
backspin. Despite its variety of derivatives, the scientific litera- operation "AND". Manual searches in reference lists of
ture describing the backhand groundstroke production has not selected published papers were also performed. The arti-
been reviewed as extensively as with the serve and the forehand. cles were restricted to those written in English. Full publi-
The purpose of this article is to review the research describing cations and abstracts were screened, and all relevant stud-
the mechanics of one and two-handed backhands, with a critical ies were retrieved. Studies needed to satisfy the following
focus on its application to clinicians and coaches. One hundred criteria for inclusion in the review: (a) contain biome-
and thirty four articles satisfied a key word search (tennis, back- chanical or other descriptive (such as accuracy or fre-
hand) in relevant databases and manual search, with only 61 of quency) data on one- or/and two- handed backhands or
those articles considered directly relevant to our review. The (b) among those studies related to tennis injuries, docu-
consensus of this research supports major differences between ment technical considerations or observations related to
both the one- and two-handed strokes, chiefly about their re- the backhand. Ultimately, 50 references were selected
spective contributions of trunk rotation and the role of the non- from the 125 previously selected articles from the data-
dominant upper extremity. Two-handed backhand strokes rely base searches as well as an additional eleven references
more on trunk rotation for the generation of racquet velocity, retrieved from the manual search. Among them, 51 were
while the one-handed backhands utilize segmental rotations of research-based papers and a further 10 articles were based
the upper limb to develop comparable racquet speeds. There on expert opinion. The objective of this paper is to subse-
remains considerable scope for future research to examine ex- quently review these contributions to our understanding
pertise, age and/or gender-related kinematic differences to of backhand technique, with a critical focus on their im-
strengthen the practitioner's understanding of the key mechani- plications for clinicians and coaches.
cal considerations that may shape the development of proficient
backhand strokes. Backhand's place in the modern game
Backhand vs Forehand: In analyzing the distribution of
Key words: Coaching, skill development, groundstrokes, injury the final strokes in a rally as a function of point outcome
prevention. in elite level tennis players, Cam et al. (2013) revealed
that forehands are associated with a greater number of
Introduction points won, while more points are lost with backhands
played as the final shot. Interestingly, players have gener-
The backhand and the forehand are the two groundstrokes ally been found to serve to an opponent's backhand more
in tennis. Although the forehand may be considered the often when under pressure as it is considered the weaker
most important stroke behind the serve in the modern side (Bailey and McGarrity, 2012). Across all forms of
game (Brabenec, 2000), the evolution of the backhand competitive play, including professional tennis, backhand
(BH) represents one of the biggest changes in tennis over strokes are less frequently played than forehand strokes
the past three decades. Indeed, where the one-handed (Johnson et al., 2006; Pellett and Lox, 1997; Ridhwan et
backhand (1BH) was almost exclusively the backhand of al., 2010). This imbalance has also transcended the rally
choice before the 1980s, the two-handed backhand (2BH) tests of young beginner players, where Farrow and Reid
has all but assumed that mantle in more recent times; (2010) reported such players prefer to hit forehands rather
often rivaling the forehand for importance among the than backhands. Indeed, the heightened relative strength
professional game's best players (Reid, 2001). However, demands to hit a backhand stroke (Giangarra et al., 1993)
many high level players using a 2BH have also developed may help explain this observation with young players,
the ability to effectively hit slice 1BH, therein retaining while it would appear a tactical choice � potentially relat-
tactical versatility (Saviano, 2002). Given this backdrop, ed to ease with which inside-out forehands but not back-
and the need for coaches to understand and tailor their hands can be played (Kovacs and Ramos, 2011) � at the
teaching to the mechanical nuance of the 1BH and 2BH higher performance levels.
strokes, it is interesting to note that the backhand has
attracted less research attention than the serve and fore- Ball velocity: The preferential use of the forehand
hand. may also be partly explained by evidence suggesting that
forehands produce higher ball velocities for elite male
Received: 24 August 2014 / Accepted: 27 November / Published (online): 01 March 2015
Genevois et al. 195
Figure 1. Examples of two key events in one-and two-handed backhands with the end of the backswing (1A
and 2A) and the contact of the racquet with the ball (1B and 2B).
players (Fernandez-Fernandez et al., 2010; Landlinger et ing both techniques � logically owing to their quite dis-
al., 2012; Pluim et al., 2006), for intermediate-level male parate coordination. However, studies comparing elite and
players (Mavvidis et al., 2005), and elite female players national level players performing either 1BH or 2BH
(Kraemer et al., 1995; 2003). observed comparable horizontal racquet velocities (Aku-
tagawa and Kojima, 2005; Reid and Elliott, 2002), post-
Stroke accuracy: Inter-stroke differences in accu- impact ball velocities (Fanchiang et al., 2013) and accura-
racy appear to relate to the protocol used. For example, in cy (Muhamad et al., 2011). These results suggest that both
two studies where ball velocity was not considered, no racquet or ball velocity and stroke accuracy should not
differences in hitting accuracy were reported between prejudice any choice regarding which backhand to use;
forehand and backhand shots played crosscourt (CC) and rather other factors need to be taken into account. Accord-
down the line (DL) by elite tennis players during simulat- ingly, the kinematic differences between each backhand
ed tennis matchplay (Davey et al., 2002) or in a hitting stroke need to be appreciated, and then considered within
accuracy tennis test (Strecker et al., 2011). Two studies the context of each individual player's kinanthropometry,
reported hitting accuracy to be similarly independent of coordination skill and style (Reid, 2001).
stroke, as well as gender (Lyons et al., 2013; Theodoros et
al., 2008), but significantly influenced by skill level (Ly- Figure 2. Spatial reference relative to the tennis court for a
ons et al., 2013). However, these findings that point to right handed player's hip alignment (RH, right hip,-LH, left
analogous accuracy between the groundstrokes contrast hip), the shoulder alignment (RS, right shoulder �LS, left
with the work of Mavvidis et al. (2010), who revealed that shoulder), and the separation angle () at the end of the
competitive young male and female players (13.6 � 1.4 backswing for a backhand.
years) achieved a significantly higher accuracy with the
forehand than with the backhand, as well as Perry et al. Definition of stroke
(2004) who reported that adolescent male and female The backhand stroke is divided into three common phases
competitive tennis players hit their backhands, but not (Ryu et al., 1988). The preparation phase begins from the
forehands, with better accuracy and greater ball velocity displacement of the racquet backward and ends at the
directing the ball CC compared to DL. Finally, when moment of reversing the direction (Figures 1A/2A); the
generating near maximal ball velocities, Landlinger et al. acceleration can be considered from the start of the rac-
(2012) has illustrated heightened accuracy for forehands quet forward displacement to the ball contact (Figures
compared with backhands (Landlinger, 2012). This latter 1B/2B); the follow through phase begins from the con-
empirical finding, albeit limited to shots played CC, is tact point and finishes at the end of the racquet forward
interesting in that it could be argued that these observed
differences in accuracy are unsurprising if one shot is
played (or practiced) more than the other. Given this
inconclusive backdrop, further studies are clearly war-
ranted to investigate the relationship between ball veloci-
ty, accuracy and stroke type among different playing
levels.
Comparison between the one- and two-handed back-
hands
One of the most contemplated questions among tennis
coaches is whether one of the two techniques is superior.
From a scientific point of view, no study has provided a
clear-cut answer. This can be explained, at least in part,
by the difficulty associated with the same player master-
196 The tennis backhand groundstrokes
movement. and the 2BH, a closed kinetic chain action with eight
degrees of freedom. However, as interesting as this model
Definition of trunk angles is for researchers, in the opinion of the authors, these
Only one spatial model has been used to compare the additional degrees of freedom present an interpretive
results of literature, (Figure 2). The shoulder alignment challenge for coaches and thus become more difficult to
angle defines an angle between the left shoulder � right transfer to the field.
shoulder and the baseline, projected down onto the sur-
face of the court. The hip alignment angle is similarly From a functional point of view, racquet velocity
defined. When either the hips or shoulders are aligned is the product of the relative rotational movements of (a)
parallel to the baseline, a 0� angle is noted. When they seven angular velocity components involved with prepa-
rotate such that they were perpendicular to the baseline, a ration (shoulder internal rotation, shoulder extension and
90� angle is recorded. The angular difference between the shoulder adduction; elbow flexion and pronation; wrist
shoulder alignment and hip alignment (trunk twist) is flexion and ulnar deviation) and power generation (shoul-
defined as the separation angle (Elliott, 2003), and is der external rotation, shoulder flexion and shoulder ab-
shown in figure 3. A positive separation angle indicates a duction; elbow extension and supination; wrist extension
greater shoulder alignment rotation angle relative to the and radial deviation) (Figure 3), and (b) the velocity of
hip alignment angle, while a negative value indicates a the centre of the shoulder joint that is the result of the
greater hip alignment rotation angle relative to the shoul- angular velocity of the trunk and the velocities the two hip
der alignment rotation angle. joints centres, which are determined by the various rota-
tional velocities in the lower extremities (Mester, 2006).
Segmental coordination
The power of a tennis stroke is characterized by the veloc- Logically, as both upper extremities are connected
ity of the racquet-head at impact, which in turn develops to the racquet in the 2BH, this leads to differences in the
through the aggregated segmental rotation and energy angular displacements of the different segments during
flow from the feet, legs, trunk, arm to the hand/racquet; the three phases of the two strokes.
otherwise referred to as the kinetic chain (Kibler et al.,
2004). Researchers, in effectively taking the role of the Backswing
legs for granted, have variously represented the 1BH as a Shoulder and hip alignment
five-stage multisegment stroke involving trunk rotations Reid and Elliott (2002) have demonstrated that both
(hip and shoulder alignments), together with rotation shoulder and hip alignment angles related to the baseline
about the shoulder (upper arm), elbow and wrist (Elliott et at the end of the backswing were larger in 1BH than in
al., 1989; Groppel, 1978; Reid and Elliott, 2002; Wang et 2BH, but also that the shoulder alignment angle was larg-
al., 1998). Similarly, the 2BH has been described as a er than the hip alignment angle for both BH. (Table 1 and
five-stage multisegment stroke, where elbow joint motion Figure 1A/2A).
helps contribute to racquet speed and positioning, or a
four-stage multisegment stroke during which the elbows The degree of the shoulder and hip alignment rota-
remain relatively extended throughout the forward swing tion angles at the end of completion of the backswing
to impact (Reid and Elliot, 2002). Recently, Stepien et al. appears to be affected by several factors such as stroke
(2011) challenged these models as too simplistic, suggest- direction, height of impact, post impact ball velocity and
ing that the 1BH was more appropriately considered an gender. Indeed, Reid and Elliott (2002) reported that the
open kinetic chain action with seven degrees of freedom shoulder alignment angle was larger when playing DL
than when playing CC for both BH, but that the hip
alignment angle was larger only for the 2BH. Elliott and
Christmas (1995) observed a larger shoulder alignment
Figure 3. Pictorial definitions of seven joint angles used to detect upper-limb motions during tennis backhand
strokes. (1) shoulder internal (A)/external (B) rotation, (2) shoulder flexion (A)/extension (B), (3) shoulder ab-
duction (A)/adduction (B), (4) elbow flexion (+)/extension (-), (5) elbow pronation (A)/supination (B), (6) wrist
flexion (+)/extension (-), and (7) wrist ulnar (+)/ radial (-) deviation.
Genevois et al. 197
Table 1. Mean (�Standard deviation) for hips and shoulder angle values during one-(1BH) and two-handed (2BH) backhand
strokes at the completion of the backswing (preparation phase).
Authors sample Stroke direction Shoulders rotation (�) Hips rotation (�)
and type 1 BH 2 BH 1 BH 2 BH
Reid & Elliott (2002) 18 male collegiate players CC On-C 117.2 (7.0) 79.5 (11.5) 90.1 (15.8) 58.0 (8.8)
DL On-C 120.9 (6.8) 87.2 (9.5) 88.5 (9.4) 68.8 (10.8)
Elliott et al. (1989) 7 male state ranked CC topspin On-C 123.0 NR
players and 1 female DL topspin On-C 129.1 NR
internally ranked player
Elliot & Christmas 13 male high DL backspin On-C 130 NR
(1995) performance players
Akutagawa & 14 male collegiate players DL (laboratory condition) NR 111.6 (9.3) 117.7 (9.3)
Kojima (2005)
CC = cross-court; DL= down the line; NR = not reported; On-C = On-court.
angle for a shoulder height impact compared with a hip Lower limb and hip kinetics: The role of the lower ex-
height impact during a backspin 1BH. Finally, during the tremities in the two backhands further illustrates their
1BH, the results of Fanchiang et al. (2013) showed a varying coordinative strategies. Although hip rotation is
significant positive relationship between post-impact ball the first segmental rotation for both BH techniques (Reid
velocity and hip and shoulder alignment rotation angles and Elliott, 2002; Kawasaki et al., 2005; Stepien et al.,
for both genders (p < 0.05). They also showed a tendency 2011), Akutagawa and Kojima (2005) observed a signifi-
of female players to utilize about 10% more hip and cant difference in hip joint moments between the two
shoulder alignment rotation angles than male players in techniques between the start of the forward rotation of the
generating their racquet velocity. One can suggest that pelvis and the start of racquet's forward movement. A
these differences between genders are related to compara- large hip joint adduction moment was created by the front
tively less strength and then a need to a longer accelera- leg in the 1BH, whereas, a large hip joint extension mo-
tion drive for the female players. The results of Ellen- ment was created by the back leg in the 2BH. Noteworthy
becker and Roetert (2004) support this assertion, demon- is that the back leg's hip extension moment and the angu-
strating that tennis female players' isokinetic trunk rota- lar displacement of the pelvis during the 2BH are compa-
tion strength was almost 20% lower than that of the male rable with those observed by Iino and Kojima (2001)
players on the backhand side. Moreover, Kibele et al. during a forehand stroke, thus suggesting certain analogy
(2009) also found that maximal trunk rotation angle was between the roles of the lower extremities in trunk rota-
the most significant kinematic parameter correlated to tion in 2BH and forehand strokes. This then supports the
post-impact ball velocity for young players aged between observation of Yandell (1998) that the function of the
10 and 12 years with different skill levels (r = 0.7) lower limbs in the 2BH is similar to that used to hit a
forehand on the opposite side of the body.
Although the results of the studies cited above are
interesting to better understand the differences between Angular displacement: Most of studies have
both BH at the end of the backswing, their comparison demonstrated significant differences in angular kinemat-
should be made with caution due to different methodolo- ics between 1BH and 2BH during the acceleration phase
gies used. Some studies used a ball machine to project the (Table 2 and Figure 1B/2B). The hip and shoulder align-
ball (Elliott et al., 1989; Elliott and Christmas, 1995; ment rotation angles are relatively more pronounced dur-
Kibele et al., 2009; Reid and Elliott, 2002), while others ing the acceleration phase of the 2BH. Moreover, 1BH
used a long inclined flute devised to reduce variation of strokes show a significantly smaller axial rotation angle of
the contact points between the racquet and the ball (Aku- the shoulder against the pelvis (separation angle) and that
tagawa and Kojima, 2005; Fanchiang et al., 2013). In of the pelvis against the feet during the acceleration phase
addition, the difference in time when maximal hip align- (Kawasaki et al., 2005). Fanchiang et al. (2013) observed
ment rotation is measured could explain the larger value that the 2BH required significantly more (12%) shoulder
observed by Akutagawa and Kojima (2005). That is, they rotation than the 1BH during the acceleration phase. This
measured the maximal hip alignment rotation before the can be explained by the fact that during a 2BH played at
beginning of its forward rotation, while other studies waist height, the shoulder alignment rotates beyond the
measured it at the beginning of the racquet forward hip alignment, which is not the case during a 1BH played
movement, when hips might have started to rotate for- at the same height. This is confirmed by the results of
ward before the completion of the backswing (Akutagawa Stepien et al. (2011) who reported a positive separation
and Kojima, 2005) because the upper body rotation fol- angle (by subtracting the shoulder alignment angle from
lowed the pelvis rotation (Kawasaki et al., 2005). the hip alignment angle at the moment of contact) for the
1BH and a negative one for the 2BH (+9.2 � 7.2� vs. 6.4
This shoulder and hip alignment characteristics in- � 4.3�, respectively). Concerning the range through
fluence the racquet position at the end of the backswing in which the hips rotate during the acceleration phase, Fan-
the same way, namely an augmented displacement in chiang et al. (2013) reported males to use significantly
1BH compared with 2BH (Reid and Elliott, 2002). less hip rotation than females in the 1BH stroke, but more
hip rotation than female players when hitting maximal
Acceleration phase
198 The tennis backhand groundstrokes
Table 2. Mean (�Standard deviation) for hips and shoulder angular rotation values during one-(1BH) and two-handed (2BH)
backhand strokes from the initiation of forward swing to ball contact (acceleration phase).
Authors Sample Stroke direction Shoulders rotation (�) Hips rotation (�)
1 BH 2 BH 1 BH 2 BH
Stepien et al. (2011) 9 male experienced coaches DL 30.1 (10.6) 71.1 (13.8)## 19.0 (6.9) 47.4 (10.3)##
Akutagawa & Kojima (2005) 14 male Colleg Players DL NR 31.4 (8.3) 54.4 (9.0)#
Fanchiang et al. (2013) 5 male Colleg Players DL 51.0 (16.0) 85.0 (12.0)# 26.0 (22.0) 59.0 (12.0)#
Fanchiang et al. (2013) 5 female Colleg Players DL 59.0 (27.0) 85.0 (13.0)# 33.0 (24.0) 43.0 (14.0)#
Reid & Elliott (2002) 18 male Colleg Players CC 51.4* 65.3 * 35.9 * 36.1*
DL 50.3 * 64 * 30.1* 36.6*
Colleg = collegiate; CC = cross-court; DL= down the line (laboratory condition); NR=not reported. * = values from average differences between
data noted at the end of the backswing and at impact.
velocity 2BH strokes. These authors noted also that the showed that the intermediate group created significantly
trunk twist was larger in the 2BH compared with the 1BH higher linear momentum about all three axes of the trunk
for both genders (29.4 vs. 20.1�, respectively), and larger than the advanced group, yet failed to generate higher
still for the females compared with male players (40 vs. hitting speeds. The subsequent suggestion was that ad-
26.3�, respectively). vanced players reduced trunk linear movement to create a
more stable axis of rotation about which the other seg-
Thus it is evident that the 1BH and 2BH involve ments could rotate.
different strategies to develop horizontal racquet velocity
at impact. Indeed, 2BH strokes rely comparatively more Upper limb rotations: Significant differences in
on trunk rotation whereas the 1BH does the same with the angular segment positions at impact have been observed
rotations of the upper limb joints of the hitting arm (Ka- at the elbow, with the dominant arm being more flexed
wasaki et al., 2005). Conceptually and in general terms, and the wrist more extended in the 2BH (Reid and Elliott,
comparable linear racquet velocities at impact are 2002). Stepien et al. (2011) argued that the dominant side
achieved by either increasing the radius of rotation of the plays the role of stabilizing the non-dominant extremity
racquet swing in the 1BH, and by increasing angular during the 2BH stroke. The role of the non-dominant side
velocities because of a shorter hitting radius in the 2BH as an important contributor to horizontal racquet velocity
technique. generation at impact is offered some support with the
linear velocities of hip, shoulder, elbow and wrist of the
Comparison of momentum across strokes: The non-dominant side being reported as higher than those of
more pronounced use of trunk rotation during the acceler- same joints on the dominant side of players (Stepien et al.,
ation phase of the 2BH leads to a larger angular momen- 2011). Further, higher elbow flexor/extensor electromyo-
tum for the trunk and racquet compared with the upper graphic ratios were observed in the non-dominant arm of
extremity joints (Wang et al., 2010). This is confirmed by skilled double-handed backhand players � not dissimilar
the mean angular velocity of the pelvis during the forward to those observed in the dominant arm of skilled single-
swing phase in the 2BH which was significantly larger handed forehand, during the acceleration phase (Huang et
than in the 1BH (538.5 � 194.8 vs. 280.7 � 108.8 degs-1), al., 2005). Thus, it's unsurprising that Eng and Hagler
respectively) (Akutagawa et al., 2005). (2014) have observed that male and female players ranked
in the professional top 100 and using the 2BH, adopted
In contrast, Wang et al. (2005) observed that the eastern forehand grips with their non-dominant hands.
linear momentum of the trunk is more pronounced in the Moreover, Stepien (2012) noted different muscle activa-
1BH. The authors argued that forward, leftward, and tions during the acceleration phase of 1BH and 2BH
upward trunk movements are essential for generating the played with similar racquet velocities. Indeed, the normal-
necessary linear momentum of the racquet, and that stabi- ized activities of the anterior and posterior deltoid, pecto-
lization of the trunk is also considered to be very effective ralis major, brachioradialis, and biceps brachii and triceps
for the sequential transfer of the high force and the energy brachii muscles during 2BH were higher in both limbs
through the trunk. However, further studies are warranted than in 1BH, with the lone exception being the triceps
to investigate the obvious question of when does this brachial muscle. As the triceps brachial muscle is respon-
stabilization happen and how it is different to what is sible for elbow joint extension, this may explain the pre-
observed in the 2BH. In their critique of the 1BH slice, viously reported different elbow joint angular positions of
Elliott and Christmas (1995) observed a similar phenom, the dominant arms observed at impact between both BHs.
where trunk rotation and upper arm movement accounted Elbow extension leads to a relatively straight but not fully
for approximately 15% of the racquet velocity at impact extended upper limb at impact for both backspin ( 170�)
but with a stable trunk at impact irrespective of the height and topspin ( 164�) 1BH (Elliott et al., 1989; Elliott and
of ball contact (shoulders or hips height). They also ob- Christmas, 1995; Reid and Elliott, 2002). In this way, the
served that the shoulder alignment was relatively constant upper limb is not "locked" so as to avoid undue stress on
during the early part of the follow through, which could the elbow region. Wang et al. (1998) reported a 35.3 �
contribute to the trunk stability. 14.4� of elbow joint extension during the acceleration
phase of topspin 1BH with the maximum angular velocity
From a coaching point of view, Wang et al. (2010) occurring at the instant prior to impact. Finally, Elliott
demonstrated that the three dimension components of and Christmas (1995) estimated that the elbow joint ex-
trunk linear movement not only do not contribute to pow- tension accounts for approximately 25% of the racquet
er generation during the 2BH stroke, but they may even
increase body instability and waste energy during the
stroke. Indeed, the comparison of expertise in their study
Genevois et al. 199
velocity at impact during a backspin 1BH, while ball 2BH, but also further forward for a BH played CC com-
speed has been shown to share a negative association with pared with the DL (Reid and Elliott, 2002). Important to
rebound angle in the same shot (Chiang et al, 2005). note here though is that the mid-point of players' hips
vary between the two strokes, meaning that the disparity
With regard to the tactical use of different ball in impact locations may be less pronounced if referenced
spins, coaches should understand that for players using differently. By comparing the results of Elliott et al.
2BH, the 1BH backspin requires a different co-ordination (1989) with those of Elliott and Christmas (1995), we can
pattern while more subtle adaptations are needed by those also observe a variation in the impact position of slice and
using 1BH. Indeed, King et al. (2011) observed that for topspin 1BH strokes, with the latter impacted further
similar ball�racket impact conditions, there were compa- forward. This could be explained, in part, by the different
rable angle�time relationships at the wrist and elbow grips preferentially used to perform both strokes. Indeed,
joints but with the major kinematic differences evident at an eastern or western grip is mainly advocated for topspin
the shoulder between 1BH topspin and backspin strokes. strokes that are impacted forward of the front foot com-
The major movements of the shoulder joint in the topspin pared with a continental grip that is advocated for a back-
1BH are flexion and abduction (King et al., 2011; Wang spin stroke.
et al., 1998), while extension and abduction apply to the
slice 1BH (Elliott and Christmass, 1995; King et al., Follow-through
2011). The work of Elliott and Christmas (1995) implies, The follow-through enables the development of peak
by extension, that despite these different joint actions, racquet speed at impact, while permitting the arm to slow
similar racquet velocities at impact are produced for a under control to reduce peak loading (Elliott et al., 2009).
backspin 1BH and topspin 1BH (Elliott et al., 1989). The middle deltoid, supraspinatus, infraspinatus and bi-
Finally, the role of external rotation and abduction in the ceps brachii muscles are most active in this phase during a
dominant arm during the 1BH is evidenced through the flat 1BH, with the biceps brachii muscular activity repre-
greater activity of the supraspinatus, infraspinatus, and the senting an effort to control extension at the elbow (Ryu et
middle deltoid muscles during the acceleration phase of al, 1988).
flat 1BH (Ryu et al., 1988). All of these elements suggest
that players using 2BH should learn the backspin 1BH Although important, the kinematics of this phase
early in the stroke development process. In this way, are poorly understood, and further studies are warranted
coaches can focus on promoting the use of the continental both from a performance and injury prevention perspec-
grip with their players' dominant hands (the right hand for tive. Indeed, the different muscular eccentric contractions
right-handers) as it provides more flexibility for a variety involved in the follow-through to decelerate the racquet
of shots, especially the one-handed backspin backhand and the body could be present a risk of injury occurrence
stroke (Crespo and Milley, 1998). in case of insufficient eccentric strength (Kovacs et al.,
2008).
Timing of the acceleration phase: Studies have
shown that average maximal linear velocities of segment Implications for injury
end points increase from the hip to wrist for both backspin A proper technique is needed both for performance and
(Elliott and Christmas, 1995) and topspin 1BH and 2BH injury prevention. As mentioned above, 2BH strokes rely
strokes (Stepien et al., 2011; Wang et al., 2010) and that comparatively more on trunk rotation, whereas the 1BH
their relative order of occurrence is similar. However, does the same with the rotations of the upper limb joints
their timing relative to impact occurs earlier during the of the hitting arm, which leads to different injury profiles.
1BH than in the 2BH. The 2BH is also characterized by
end point velocities of the segments on the non-dominant Improper movements of the 1BH drive account for
side reaching their peak just before or at the moment of approximately 90 percent of tennis elbow injuries (Ellen-
ball/racquet contact (Stepien et al., 2011). These results becker, 1995; Hang and Peng 1984; Renstrom, 2002).
are in line with those of Reid and Elliott (2002), who Indeed, a greater incidence of tennis elbow has been ob-
observed that mean maximum pre-impact horizontal ac- served when the 1BH is executed with a flexed wrist
celerations of the racquet tip to have occurred significant- instead of a wrist moving further into extension at impact
ly earlier in the 1BH when compared with the 2BH to counteract the force applied by the ball at the instant of
stroke, as well as the findings of Akutagawa and Kojima ball�racquet impact, (Blackwell and Cole, 1994). Moreo-
(2005) who reported shorter 2BH mean swing times com- ver, Wei et al. (2006) reported that more shock impact
pared to 1BH (0.5 � 0.1 and 0.4 � 0.1 s respectively). transmission from the racquet to the elbow joint occurs
From a tactical point of view, the shorter forward swing with large wrist flexor and extensor EMG activities dur-
of the 2BH and the delayed horizontal acceleration may ing the follow-through phase of the 1BH, effectively
provide opponents with less time to detect any kinematic underlining the importance of a firm grip. Kelley et al.
change associated with the intended direction and trajec- (1994) observed that the injured players had significantly
tory of the shot (Reid and Elliott, 2002). greater activity for the wrist extensors and pronator teres
muscles during ball impact and early follow-through,
Impact almost certainly caused by sub-optimal mechanics includ-
Techniques and stroke direction have been shown to af- ing a "leading elbow", wrist extension over the impact
fect the ball / racquet contact positions in the sagittal phase and an open racquet face at impact, as well as ball
plane. Relative to the mid-point of players' hips, impact contact on the lower half of the string bed. Consequently
of the 1BH is significantly further forward than during the off-center impacts below the longitudinal axis of the rac-
200 The tennis backhand groundstrokes
quet may be a substantial contributing factor for tennis players also needs to be considered when choosing be-
elbow injuries with a tight grip aggravating the effect due tween the 1- or 2BH. For example, the 2BH is the stroke
to high eccentric wrist extension torques and forced wrist of choice of most baseline players, while all-court players
flexion (King et al., 2012). Finally, the determination of appear more likely to adopt a 1BH owing to the ease of
appropriate grip size for individual players may help to transition in to hitting a slice approach shots and back-
mitigate injury risk, as grip size has been reported to re- hand volleys, among other potential advantages.
late to loading of the wrist extensor tendon (Rossi et al,
2014). Future research directions
If the scientific litterature reveals dissimilar patterns of
Interestingly, Wu et al. (2001) demonstrated the driving the racquet in both BHs, it is also clear that there
importance of a sufficiently long backswing in a 1BH remains considerable scope for future research to examine
stroke to reduce the load on the upper extremity. In their the inter-relationships between backhand mechanics. For
study, 1BHs that hit with a short backswing had signifi- example, it would be instructive to investigate the kine-
cantly shorter contact duration and a greater peak result- matics of both techniques (1BH and 2BH) performed by
ant impact force than those with a long backswing (8 � 3 players of different skill levels and genders to more fully
ms vs. 16 � 4 ms, and 330.0 � 140.7 vs. 180.8 � 49.1 N, understand their coordinative differences. Moreover, it
respectively) irrespective of skill level. Thus, when teach- would be of interest to investigate the influence of the
ing the 1BH stroke, a correct transfer of the momentum technique used (1- or 2BH) on the performance and the
from proximal (trunk) to distal (hand) segments should be kinematics of a backspin 1BH. Finally, with injury pre-
emphasized, from both performance and injury prevention vention in mind, the inter-relationships between backhand
perspectives. stroke performance, kinematics/kinetics and the anthro-
pometry of players may provide useful insights for coach-
Iwamoto et al. (2013) demonstrated that the direc- es and clinicians alike.
tion of the front foot relative to the net when playing a
simulated 2BH with a closed stance influences the risk of Conclusion
ankle inversion sprain and heightens the stress on the
knee. Conscious of these perils, Ellenbecker (2006) has Whether played with a single hand or in its two-handed
suggested that a placement of the front foot approximately form, the appropriateness of a player's backhand selection
about a 45 degree angle relative to the baseline helps to is key. Whatever the choice, the mechanical efficiency of
facilitate additional body rotation and decrease the stress an individual's strokes often determine the level of suc-
on the hip, knee, and ankle joints of the front leg. With cess experienced by the recreational, competitive, and
regard to the loads imposed on the spinal joints, Kawasaki elite tennis player. If the two-handed backhand has often
et al. (2005) these results suggest that they are larger in been privileged in the young player development, the
2BH than in 1BH. equipment scaling allows now coaches to teach the one-
handed backhand with a proper technique, thus improving
Implications for stroke development performance but also decreasing the risk of tennis-elbow
Among the factors that could explain the preferential injury.
choice of the 2BH in the learning process, one could cite
the greater strength required to perform the 1BH com- The aims of this article were to provide an insight
pared with the 2BH (Giangarra et al., 1993), but also the about differences between backhand techniques in order
greater segment co-ordination that is indicative of the to help coaches in their teaching process. However, fur-
1BH (Groppel, 1984). Before the equipment scaling de- ther studies are clearly needed to fully understand the key
velopment (tennis ball modification, court and racquet coordinative differences across male and female players
size), children learned with adult racquets and coaches of varying skill levels using both backhand techniques.
mainly taught the 2BH allowing their young competition
players to be more performant. Currently, children learn References
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Cyril Genevois
UCB Lyon 1 � UFRSTAPS � CRIS EA 647, 27-29, bd du 11
novembre 1918, 69622 Villeurbanne Cedex, France