Racquet Sports

Chapter 48
Racquet Sports
MARK HARGREAVES
Introduction
Racquet sports are played in all parts of the
world and, in addition to being a popular form
of recreational activity, have well-developed
professional circuits and are represented at the
Olympic Games. These games are played either
on a divided court area across a net (e.g. tennis,
badminton) or on a common court against a wall
(e.g. squash, racquetball). Table tennis provides a
slight variation on these general themes. The
nutritional requirements for racquet sports will
vary greatly between the sports and between
individuals and are likely to be determined by a
number of factors. Of most importance is the
level of energy expenditure which, in turn, is
influenced by the game duration, level of participation and quantity of training/competition,
type of match (singles vs. doubles), ability of
opponent and the extent to which they dictate
playing patterns and, in the case of tennis, court
surface. Environmental conditions will have an
additional impact and are a major determinant of
fluid needs. For the purposes of this chapter, discussion will be limited to tennis, squash and badminton; however, the general principles should
apply to all racquet sports. Given the complexity
of these sports and the interactions between
cognitive and physical performance, the racquet
sports have been less studied by scientists with
an interest in sports performance.
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Physiological and metabolic demands
of racquet sports
The physiological and metabolic demands of
racquet sports have been well summarized by
Reilly (1990). In general, they can be characterized as intermittent exercise, with relatively
short bursts of activity, involving both the upper
and lower limb muscles, followed by periods of
rest. The average duration of a rally is in the
range of 4–12 s (Docherty 1982; Dawson et al.
1985; Christmass et al. 1995; Faccini & Dal Monte
1996), but competitive matches may last from
just under an hour up to several hours depending upon the number of games/sets played. For
example, some years ago a tennis match in the
Davis Cup team competition, when advantage
rather than tiebreak sets were played, lasted for
over 6 h! Of the racquet sports, tennis has the
greatest range of court surfaces, the consequence
of which is variation in the duration of rallies and
matches. Matches on grass courts tend to be characterized by shorter rallies and dominated by the
serve and volley. In contrast, matches on hard
and clay courts usually involve longer rallies
from the baseline. In general, rallies in squash
tend to be longer than those in badminton and
tennis (Docherty 1982), which may be a function
of the walled court allowing potential ‘out balls’
to remain in play.
.
Measurements of heart rate and Vo2max. during
racquet sports support the contention that these
sports can be classified as moderate- to highintensity aerobic activities, with values in the
racquet sports
Fig. 48.1 The intermittent nature of sports such as
tennis combines the demands of an endurance event
with those of repeated sprints. Photo © Allsport / G.M.
Prior.
range of 60–90% of maximal heart rate and
.
50–80% Vo2max. (Docherty 1982; Elliott et al. 1985;
Garden et al. 1986; Reilly 1990; Bergeron et al.
1991; Therminarias et al. 1991; Christmass et al.
1995; Faccini & Dal Monte 1996). The heart rate
and blood pressure responses tend to be higher
in squash and this has led to some discussion
about the risk of cardiovascular events in susceptible individuals who play squash vigorously.
The metabolic changes during racquet sports
are consistent with the cardiorespiratory
responses. Blood glucose usually increases or
remains at pre-exercise levels during relatively
short periods (45–90 min) of play (Noakes et al.
1982; Garden et al. 1986; Bergeron et al. 1991;
633
Therminarias et al. 1991; Christmass et al. 1995). It
is possible that, in the absence of carbohydrate
supplementation, blood glucose may fall during
an extended duration match (Burke & Ekblom
1982). Blood lactate levels are generally within
the 1–4 mmol · l–1 range (Noakes et al. 1982;
Garden et al. 1986; Bergeron et al. 1991; Therminarias et al. 1991), although values as high as
5–6 mmol · l–1 have been observed (Reilly 1990;
Christmass et al. 1995). While this may reflect a
period of intense activity just prior to sampling,
it nevertheless suggests the potential for significant lactate production during racquet sports.
Although no data on muscle metabolites during
racquet sports exist, there is likely to be a large
reliance on muscle glycogen, particularly during
longer matches. The observed increases in
plasma glycerol and free fatty acids (Noakes et al.
1982; Garden et al. 1986; Christmass et al. 1995),
which correlate with match duration, suggest an
increase in lipolysis. Increases in the plasma
levels of catecholamines, adrenocorticotrophic
hormone, growth hormone, renin and vasopressin, and decreases in insulin, have been
observed during racquet sports (Noakes et al.
1982; Garden et al. 1986; Therminarias et al. 1991).
The intermittent nature of racquet sports
results in a thermal load which is less than that
encountered during continuous exercise of
similar intensity. Environmental heat and
humidity will potentially have a greater impact
on thermoregulation and fluid balance during
racquet sports. For example, it is not uncommon
for the on-court temperature to be as high as
45–50°C on some days of the Australian Open
tennis tournament (held during the summer
month of January) and this creates a major challenge to the thermal and fluid balance of elite
players. Medical treatment for heat illness (i.v.
fluids and postmatch monitoring) was required
for two players in the 1997 tournament. In addition, factors such as air-conditioning, ventilation,
humidity, and heat generation from lighting
will influence the environmental conditions
when squash, badminton and tennis are played
indoors. Increases in rectal temperature of
0.8–1.5°C have been observed following tennis
634
sport-specific nutrition
(Elliot et al. 1985; Therminarias et al. 1991) and
squash (Blanksby et al. 1980; Noakes et al. 1982) in
moderate conditions and greater increases are
reported during exercise in the heat (Dawson et
al. 1985). Losses of body mass have been reported
in the range of 0.9–2 kg (Therminarias et al. 1991;
Bergeron et al. 1995), a relatively large fluid loss
which is determined by the balance between
sweat fluid losses and fluid replacement. The
opportunities for fluid replacement tend to be
greater in tennis, where there is a change of ends
every two games and a 90-s rest period. In contrast, during squash and badminton, fluid intake
is usually limited to the end of a game. Another
concern for the tournament tennis player is the
need to sometimes play more than one match per
day and to play a number of matches on successive days. During the course of several days of
tournament play, it is possible that the fluid
and electrolyte status of players is challenged
(Bergeron et al. 1995).
Nutrition for racquet sports
In general, the nutritional strategies adopted by
racquet sport competitors should adhere to the
guidelines suggested for most athletes. Total
energy intake should be sufficient to cover the
energy requirements of competition and training, which in the case of players at the elite level
can be large. For the recreational racquet sports
participant, where total energy expenditure is
less and the need to maintain an optimal body
weight by energy restriction may be greater,
there should be a greater emphasis on carbohydrate intake. Particular attention should be paid
to carbohydrate and fluid requirements for the
reasons that have been well described in previous chapters. Tournament play will create certain
difficulties in achieving nutritional goals. The
need for international travel will cause disruption to normal cycles and eating patterns and
provide food choices that differ from those
usually consumed. Adequate preparation prior
to an international trip is essential and this may
be as simple as becoming familiar with food
choices available at a tournament venue or as
involved as taking certain foods and/or supplements as part of the luggage. Most international
tournaments have excellent catering services;
however, delays due to bad weather, prolonged
matches and/or alterations in playing schedules
can interfere with eating plans. Under such
circumstances, it is advisable to have a range
of light, easily digested, high carbohydratecontaining meals available. Liquid meals/
supplements are often appropriate. The other
nutritional challenge for the tournament player
is the need for rapid recovery, since matches are
scheduled on a daily basis and if a successful
competitor is also involved in doubles, there can
be many matches over a relatively short period.
Towards the end of a tournament, it is not
uncommon for successful competitors to play
multiple games on successive days. To facilitate
rapid recovery and optimize liver and muscle
glycogen reserves and whole body hydration,
carbohydrate and fluid replacement should
be emphasized early in the recovery period.
The principles underlying this practice have
been well described in Chapters 7 and 19,
respectively.
Another aspect of nutritional practice related
to the racquet sports is the need for carbohydrate
and fluid replacement during activity. The beneficial effects of carbohydrate and fluid supplementation on performance during exercise, and
the underlying mechanisms, have been well
described in the literature (see Chapters 8, 16 and
17). It could be argued that any nutritional intervention that minimizes the risk of fatigue during
prolonged, strenuous racquet sport activity
would contribute to at least maintained, if not
improved, performance. Furthermore, given the
heavy reliance on perceptual and motor skills
in the racquet sports, attenuation of the effects
of carbohydrate depletion and dehydration on
central nervous system function is likely to
enhance performance. Relatively few studies
have directly tested such hypotheses. Mitchell et
al. (1992) observed no benefit of carbohydrate
supplementation on indices of tennis perfor-
racquet sports
mance (serve velocity/accuracy, error rates)
during 3 h of tennis play. Because a decline in
blood glucose was not observed during exercise
in the control trial, the authors speculated that
glucose availability was not limiting during the
tennis match and accordingly, carbohydrate supplementation would have little effect. In contrast,
Burke and Ekblom (1982) observed that the addition of carbohydrate to a rehydration beverage
enhanced indices of tennis performance to a
greater extent than water alone or no fluids.
Furthermore, Vergauwen et al. (1998) recently
observed that carbohydrate ingestion during 2 h
of strenuous tennis training increased performance during a shuttle running test and a specific tennis performance test that assessed error
rates, ball velocity and precision of ball placement when compared with ingestion of a sweet
placebo. Based on previous work demonstrating
the benefits of energy and fluid replacement
during continuous and intermittent exercise, it is
recommended that such practices be adopted
during racquet sports. There is little argument
that fluids should be ingested. The need for carbohydrate supplementation will depend upon
the intensity and duration of the match and is
likely to be of most benefit the longer the match
progresses. Athletes should experiment with
energy replacement beverages during training
and competition of varying duration to identify a
practice that best suits their needs.
In summary, the physiological and metabolic
demands of racquet sport training and competition are such that total energy, carbohydrate and
fluid intakes should be increased. The training
diet should contain sufficient amounts of these
nutrients, together with vitamins and minerals.
During periods of intense training and tournament competition, carbohydrate and fluid
intake may need to be increased to facilitate
rapid recovery on a daily basis. Ingestion of
fluid during matches will minimize the risk of
dehydration and carbohydrate supplementation
should also be considered, especially when
duration is extended. Given the large number of
factors that will influence the nutritional needs of
635
racquet sport competitors, nutritional guidelines
should be formulated on an individual basis.
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