The effect of Ramadan fasting on sports performance has been
the subject of very varied and diverse studies. The conclusions drawn are,
moreover, divergent. However, the exact mechanisms responsible for the declines
in these performances are not clearly defined
17
(Barret al., 1999, Maughan, 2010). Indeed,
multiple and interlocking factors related to the athlete, himself, the nature
of the sport, the weather conditions that the athlete faces, the schedule and
the duration of the exercise to be performed, influence the effect of fasting
on sports performance. Maughan et al (2010) reported that the
effect of Ramadan fasting differs from one sporting discipline to another and
from one athlete to another. They also noted that there are several difficult
situations that the athlete faces when he fasts during Ramadan. These include
endurance events in hot or humid weather, multi-day events, or late-night
events, or the example of athletes who face challenges during competitions
lasting more than 30 minutes at high temperature. As for Armstrong et
al., (1985), they put forward the example of the competitions that are
scheduled at the end of the day of the month of Ramadan. They note that fasting
athletes may be hypo hydrated before the start of competition, which is likely
to lead to a loss of performance. Warned, some athletes take before the
competition, certain provisions to avoid and limit this hypo hydration.
However, the inability to ingest fluids during exercise remains unresolved and
the risk of loss of performance remains high (American College of
Sports Medicine, 2007).
Burke et al., 2006; Shirreffs et al., 2006
also pose the physiological problem of the inability to replace sweat
losses and ingest carbohydrates to begin the process of replenishing muscle
glycogen in the immediate recovery period at a competition. That said, other
factors that are responsible for the fall in athletic performance among Ramadan
athletes have also been identified .In addition, the time of day when the test
is performed, the physical condition of the subjects and the measures taken can
be determining factors (Reilly and Waterhouse, 2007). In
addition, although there is a decrease in athletic performance during Ramadan,
it is unclear whether there is a systematic decline in physiological variables
related to exercise (Waterhouse, 2010). On the other hand, and
to our knowledge, research studies the impact of Ramadan fasting on disciplines
where exercise protocols are the most difficult ( Intermittent high intensity
exercises requiring physical and cognitive skills such as marathon, high-level
football match, tennis matches, road cycling competitions, etc.) especially in
hot conditions are very rare or nonexistent (Maughan et al.,
2010).
On aerobic-dominated performance, Sweileh et al.
(1992) showed that maximum oxygen uptake (VO2 max) decreases during
the first week of Ramadan, then returns to values before Ramadan at the last
week of this month. This can be explained by a physiological adaptation linked
to fasting. In addition, Sweileh et al. (1992) also found a
lower resting VO2 in the afternoon during Ramadan. This indicates, according to
Meckel et al., (2008) a strategy for
18
conserving energy reserves. It should be noted that fasting
has also been associated with decreased venous return, resulting in lower
sympathetic tone, leading to a reduction in blood pressure, heart rate and
cardiac output (Stokholm et al., 1991; Al Suwaidi et al., 2006).
These physiological changes can negatively influence the ability of
physical work and promote the deterioration of sports performance
(Meckel et al., 2008).Similarly, Meckel et al., (2008)
observed that Ramadan fasting leads to a reduction in aerobic
endurance performance (3000m run) in young footballers (14-16 years old). These
authors did not indicate the time of day or the season during which the tests
were performed. Chennaoui et al., (2009) also noted, in
middle-aged runners who train 6 to 10 times a week, a decrease in maximum
aerobic speed on the first and the third week of Ramadan in September compared
with before Ramadan. The duration of fasting was around 13 hours a day. These
authors explained the drop in performance observed by maintaining the same
volume of training during Ramadan despite the constraints associated with it
(sleep deprivation, caloric restriction and fatigue).
Similarly, Kirkendall et al., (2008) noted
that the endurance of young footballers assessed by the shuttle run test
established by Léger and Lambert, 1982, was affected
during the second week of Ramadan but this capacity is restored towards the end
of month of fasting. The authors explain the divergence of their results with
the previous results (Zerguini et al., 2007, Meckel et al., 2008)
by the change of the living conditions during Ramadan since in their
study, the young footballers resided together and were under control throughout
the investigation, which is not the case for the other two studies. In
addition, the intensity and duration of the training sessions and the quality
of sleep were not changed during Ramadan. In contrast, Chaouachi et
al., (2009) found no change in maximal oxygen uptake or heart rate
peak recorded in high-level judokas that maintained high training intensity and
volume during Ramadan. These researchers explained their results by the fact
that Ramadan fasting-induced metabolic constraints, concomitant with
maintaining a high training intensity, have little effect on the performance of
high-level athletes.
In terms of anaerobic performance, Bigard et al.,
(1998) showed that the month of Ramadan affects muscular strength and
endurance. Indeed, the maximum voluntary isometric force (MVF) of the elbow
flexors decreases as of the first week of Ramadan. In addition, the MVF of knee
extensors and muscular endurance at 35% and 70% of the MVF of the knee
extensors and elbow flexors decreased at the end of the month. Similarly,
Souissi et al., (2007) showed that maximum muscle powers
(Pmax) recorded during the strength / velocity test were lower
19
during Ramadan than before Ramadan (for tests conducted in the
afternoon). On the other hand, during the Wingate test, Souissi et al.
(2007) found that the peak powers (Ppic) recorded around
17h:00 and around 21h:00 were lower during the month of
fasting and during the second week compared to before Ramadan. Moreover, the
average powers recorded around 17h:00 and 21h:00 during
the same test were lower during the fourth week of Ramadan than before Ramadan,
while they were unchanged during the second week of the month of fasting
compared to the control session Ramadan.
In addition, Meckel et al., (2008) observed
that Ramadan fasting in results in a reduction in speed endurance (6 x 40m) and
countermovement jump (CMJ) performance in young footballers (14-16 years). On
the other hand, performances in sprint (40m) and agility (4x10m shuttle race)
were not affected during this month. The experiments made by Zerguini
et al. (2007) showed that the performances recorded during the
vertical Jump tests were not affected while those recorded during the 20 m
sprint test, the dribbling speed test and the agility test were altered during
the test during the fourth week of Ramadan compared to before Ramadan. These
authors mentioned that the decrease observed was not related to fasting but
rather to environmental and motivational factors since the tests performed are
not of sufficient duration to be influenced by the availability or not of the
energy substrates. Thus the tests are unlikely to be affected by the low
caloric intake associated with the month of Ramadan. In addition,
Kirkendall et al., (2008) reported performance in sprint (7 x
30 m), dribbling (McGregor et al., 2002), CMJ, pass testing
(Ali et al., 2007) and agility 4-line agility
test(Rösch et al., 2000) were not affected in footballers
continuing their training during Ramadan. The authors explained the stability
or sometimes the improvement in performance observed during the month of
fasting by the effect of maintaining the same intensity and duration of the
training sessions and by the fact that the players live together during the
period of investigation. Similarly, Chaouachi et al. (2009)
did not report a change in performance in sprint (5 m, 10 m, 30 m),
squat jump and CMJ recorded at high level judokas who maintained a high
intensity and high training volume during Ramadan.
However, the average power recorded during the 30-second
repetitive jump test decreased towards the end of Ramadan. Chaouachi et
al., (2009) explain this decline by the effects of reduced
carbohydrate consumption and lower body mass, which results in decreased
buffering capacity during intense muscle contractions. On the other hand,
Girard and Farooq (2011) studied the impact of fasting during
the month of Ramadan on the ability to repeat sprints in children aged between
10 and 14 years and they showed that the performance during repeated
20
sprints had deteriorated at the end of Ramadan and this effect
persisted for at least two weeks while the fatigue resistance was preserved.
