Injury rates in professional soccer players during Ramadan

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Injury rates in professional soccer players duringRamadanKarim Chamari a , Monoem Haddad a , Del P. Wong b , Alexandre Dellal c & Anis Chaouachi aa Tunisian Research Laboratory “Sport Performance Optimisation”, National Center ofMedicine and Science in Sports (CNMSS), Tunis, Tunisiab Technological and Higher Education Institute of Hong Kong, Hong Kongc Olympique Lyonnais FC, Lyon, France

Version of record first published: 15 Jun 2012

To cite this article: Karim Chamari, Monoem Haddad, Del P. Wong, Alexandre Dellal & Anis Chaouachi (2012): Injury rates inprofessional soccer players during Ramadan, Journal of Sports Sciences, 30:sup1, S93-S102

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Injury rates in professional soccer players during Ramadan

KARIM CHAMARI1, MONOEM HADDAD1, DEL P. WONG2 ALEXANDRE DELLAL3,

& ANIS CHAOUACHI1

1Tunisian Research Laboratory ‘‘Sport Performance Optimisation’’, National Center of Medicine and Science in Sports

(CNMSS), Tunis, Tunisia, 2Technological and Higher Education Institute of Hong Kong, Hong Kong and 3Olympique

Lyonnais FC, Lyon, France

(Accepted 21 May 2012)

AbstractMany of the socio-cultural lifestyle and dietary changes that take place during Ramadan may affect the risk of injury inathletes, but little evidence is available. The aim of the present study was to examine the effects over two consecutive years ofthe holy month of Ramadan on injury rates in 42 professional players of a Tunisian top-level professional soccer team.Players were retrospectively organized into fasting and non-fasting groups and monitored for 3 months: 4 weeks beforeRamadan, during the month of Ramadan (4 weeks), and 4 weeks after Ramadan each year. During Ramadan, trainingstarted at 22.00 h. The circumstances (training/match) and mechanism of injury (traumatic/overuse) were recorded. Nosignificant differences between the three periods were observed for weekly mean training load, training strain, trainingduration, and Hooper’s Index (quality of sleep, and quantities of stress, delayed-onset muscle soreness, and fatigue).Compared with non-fasting players, fasters had a lower (P 5 0.05) Hooper’s Index and stress during and after Ramadan.No significant difference in injury rates was observed between fasting and non-fasting players. Nevertheless, the rates of non-contact (6.8 vs. 0.6 and 1.1) and training overuse (5.6 vs. 0.6 and 0.5) injuries were significantly higher in fasting playersduring the month of Ramadan than before or after Ramadan. In conclusion, Ramadan, along with the correspondingchanges in nutritional habits, sleeping schedule, and socio-cultural and religious events, significantly increased overuse andnon-contact injuries in fasting players despite the fact that the training load, strain, and duration were maintained.

Keywords: Religious fast, fasting soccer players, football, injury prevention

Introduction

Risk of injury is a serious concern for soccer players

and clubs in terms of health, performance, and cost.

Recently, Ekstrand and colleagues (Ekstrand, Hag-

glund, & Walden, 2011) conducted a prospective

cohort study in which world-class soccer teams (the

first team squads of 23 teams selected by the Union of

European Football Associations as belonging to the 50

best European teams) were followed for seven con-

secutive seasons (i.e. 2001 to 2008). The authors

identified 4483 injuries that occurred over 566,000 h

of exposure (i.e. 475,000 h of training and 91,000 h of

match-play), giving an incidence of injury of 8.0 per

1000 h. The incidence of injury during matches was

higher than in training (27.5 vs. 4.1; P 5 0.001). A

player sustained on average two injuries per season,

thus a team with a typical squad of 25 players can

expect about 50 injuries each season. Traumatic

injuries and hamstring strains were more frequent

during the competitive season, while overuse injuries

were more common during the pre-season. Training

and match injury incidences were stable over the 8-year

period with no significant differences between seasons.

Injury rates in training and match-play in the study

of Ekstrand et al. (2011) were consistent with the

data of Hawkins and colleagues (Hawkins, Hulse,

Wilkinson, Hodson, & Gibson, 2001), who reported

an average of 1.3 injuries per player per season in

English professional soccer. In the Swedish Premier

League, Hagglund and colleagues (Hagglund, Walden,

& Ekstrand, 2006) prospectively recorded individual

exposure and time-loss due to injuries over two full

consecutive seasons (2001 and 2002). They showed

that training and match injury rates were similar

between seasons (5.1 vs. 5.3 injuries per 1000

training hours and 25.9 vs. 22.7 injuries per 1000

match hours, respectively), but the analysis of injury

severity and injury patterns showed variations between

seasons. In a prospective study in Norway, Andersen

Correspondence: Del P. Wong, Technological and Higher Education Institute of Hong Kong, Tsing Yi, Hong Kong.

E-mail: [email protected]

Journal of Sports Sciences, 2012; 30(S1): S93–S102

ISSN 0264-0414 print/ISSN 1466-447X online � 2012 Taylor & Francis

http://dx.doi.org/10.1080/02640414.2012.696674

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and colleagues (Andersen, Tenga, Engebretsen, &

Bahr, 2004) collected videotapes and injury informa-

tion for regular league matches during the Norwegian

season of 2000 (April through October). In 174

matches, 425 incidents were recorded: 1.2 incidents

per team per match or 75.5 incidents per 1000 playing

hours. A total of 121 acute injuries were reported from

the same matches, i.e. 0.3 injuries per team per match

or 21.5 injuries per 1000 playing hours.

In an analysis of the incidence and characteristics of

injuries sustained during the 2010 FIFA (Federation

Internationale de Football Association) World Cup,

Dvorak and colleagues (Dvorak, Junge, Derman, &

Schwellnus, 2011) identified 229 injuries, of which 82

match-play and 58 training injuries were expected to

result in time-loss, giving an incidence of 40.1 match-

play and 4.4 training injuries per 1000 h. Contact with

another player was the most frequent cause of match-

play (65%) and training (40%) injuries. The data

showed that the most frequent diagnoses were thigh

strain and ankle sprain (Dvorak et al., 2011). The

incidence of match injuries during the 2010 FIFA

World Cup was lower than in the three previous

World Cups (Dvorak et al., 2011). This might have

been the result of more attention to injury prevention,

less foul play, and stricter refereeing (Dvorak et al.,

2011). Dvorak and colleagues (2011) showed that

training injuries differed substantially from match-

play injuries with respect to diagnosis and cause, but

not severity. While it could be expected that training

injuries were more often a result of overuse and non-

contact trauma than match injuries, 12 training

injuries were reported to be caused by foul play. Six

of these injuries were reported from one team (Dvorak

et al., 2011). The incidence of time-loss training

injuries was similar to those at the European

Championships (1.3–3.9 per 1000 training h) (Ek-

strand et al., 2011; Hagglund et al., 2006).

Injury risk can also be affected by the match

schedule. Indeed, Dupont et al. (2011) showed that

the injury rate can be much higher when two matches

are played in the same week, compared with a once-

a-week schedule. In the 2006 World Cup in

Germany, Dvorak et al. (2007) reported an injury

rate of 81 injuries per 1000 h of exposure, which is

slightly lower than that of Dupont et al. (2011) with

97.7 injuries per 1000 h. In this tournament, the

high rates of injury may have been linked to the

limited number of recovery days between two

matches (given that most matches were played every

3–5 days) and the repetition of matches in a

congested fixture schedule. Although some of the

players studied probably had more than 4 days of

recovery between matches, this study highlights the

higher risk of injuries when the recovery between two

matches is short. In this context, Ekstrand and

colleagues (Ekstrand, Walden, & Hagglund, 2004)

reported that a congested soccer calendar increases

the risk of injury or underperformance. Results from

that study confirm the high risk of injury during a

congested calendar. In contrast, Carling and collea-

gues (Carling, Le Gall, & Dupont, 2012) observed

no difference in the injury rate of a congested fixture

period and that outside such a period.

Rahnama and colleagues (Rahnama, Reilly, & Lees,

2002) assessed the exposure of English Premier League

players to injury risk during the 1999–2000 season by

rating the injury potential of playing actions during

competition with respect to type of playing action,

period of the game, zone of the pitch, and playing either

at home or away. The results suggested that some

playing actions were associated with higher injury risk

than others. Indeed, receiving a tackle, receiving a

‘charge’, and making a tackle were seen to be associated

with a substantial injury risk, while goal punching,

kicking the ball, shot on goal, set kick, and heading the

ball were all categorized as exposure to a significant

injury risk. Injury risk was highest in the first and last

15 min of a game, reflecting the intense engagements in

the opening period and the possible effect of fatigue in

the closing period. Injury risk was also concentrated in

the areas of the pitch where possession of the ball is

most vigorously contested, i.e. the attacking and

defending zones close to the goal. Injury potential was

no greater in away matches than in home games

(Rahnama et al., 2002). Hawkins et al. (2001) reported

the highest injury rates in the 15-min period at the end

of each half, with significantly more injuries in the

second half of matches. This may be the result of

fatigue of the muscles and other body organs as well as

depleted muscle glycogen stores (Reilly, 1997) and

players becoming hypo-hydrated (Saltin, 1973).

The relationship between fatigue and injury is hard

to quantify, but there is evidence to suggest that

fatigue is associated with injury. Empirical observa-

tions has shown that fatigued individuals are vulner-

able to injury (for a review, see Schlabach, 1994).

Fatigue may not be the sole cause of injury, but

rather a contributing factor. After reviewing the

literature regarding the aetiology of injury strains,

Worrell and Perrin (1992) reported that fatigue was

one of several factors that may contribute to the

frequency of hamstring strains.

Because muscle glycogen depletion is associated

with fatigue and injury, it should also be treated as a

possible risk factor. Muscle glycogen stores are

almost entirely derived from carbohydrate. Both

indirect and direct evidence support the notion that

depleted muscle glycogen stores contribute to injury.

Indirectly, it is quite clear that depleted muscle

glycogen stores coincide with fatigue, and fatigue in

turn is associated with injury, as mentioned above.

Although most evidence is related to relationships

rather than cause-and-effect, many researchers

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strongly do suggest a cause-and-effect relationship

between low muscle glycogen stores and injury risks

(for a review, see Schlabach, 1994). Depletion of up to

84–90% of intramuscular glycogen stores has been

observed in soccer players at the end of a soccer match

(Jacobs, Westlin, Karlsson, Rasmusson, & Houghton,

1982). Soccer players with low glycogen stores at the

start of a match had almost no glycogen left in their

working muscle and the physical performance of these

players decreased in the second half compared with

those players with higher pre-game and half-time

glycogen muscle stores (Jacobs et al., 1982). Because

there is a limited capacity to store muscle glycogen,

and because muscle glycogen is the predominant fuel

in exercise of moderate to severe intensity, the

nutritional focus should be on carbohydrate con-

sumption (for a review, see Schlabach, 1994). The

absolute amount of carbohydrate in the diet may be an

important factor for the recovery of muscle and liver

glycogen stores after training and competition (Ivy,

2001). In this context, it is important to note that an

inadequate nutrient intake and hypohydration could

affect the physical health of the athlete and possibly

contribute to sports injuries (Convertino et al., 1996).

Large sweat losses, insufficient fluid intake, and

consequent fluid deficits will likely impair perfor-

mance and may increase the risk of hyperthermia and

heat injury (Bergeron et al., 2005), stressing the

importance of appropriate hydration before training

and matches in soccer players. In this context, by

ending the day dehydrated, fasting players could be

exposed to a higher risk of injury.

Another factor associated with fatigue-related

injuries is sleep duration. Research indicates a

relationship between sleep deprivation and decreased

performance in adults (Belenky et al., 2003; Taylor,

Rogers, & Driver, 1997). Recently, Luke et al. (2011)

demonstrated that fatigue-related injuries among

athletes aged 6–18 years were related to sleeping less

than 6 h the night before the injury (P ¼ 0.028). In

contrast, the same authors reported no difference in

the average number of hours of sleep or reported

sleep-deprivation between the overuse and acute

injury groups of their study. However, since fatigue

is implicated in increased injury risk, planning for

adequate sleep before and during training and

competition is important when determining a player’s

training schedule and setting up an event schedule,

especially if travel is involved. As sleeping schedule is

radically changed during Ramadan, this month could

be a cause of higher injury risks for athletes.

Studies that describe injury risk and injury patterns

in soccer are typically conducted over seasons of

European or American Leagues (Andersen et al.,

2004; Dupont et al., 2011; Ekstrand et al., 2011).

To our knowledge, no study has focused on the injury

rates of Muslim soccer teams during the regular part of

the season or during the holy month of Ramadan.

During this period, fasting Muslims refrain from

eating, drinking, smoking, and having sexual activities

daily from dawn to sunset for 30 consecutive days.

Since the Islamic calendar is based on the lunar cycle,

which advances 11 days compared with the seasonal

year, Ramadan occurs at different times of the

seasonal year over a 33-year cycle (Chaouachi, Leiper,

Souissi, Coutts, & Chamari, 2009c), and in different

environmental conditions between years in the same

country (Leiper, Molla, & Molla, 2003; Leiper et al.,

2008). Ramadan fasting is intermittent in nature, and

there is no restriction to the amount of food or fluid

that can be consumed after dusk and before dawn. It is

supposed that most Muslim soccer players fast during

Ramadan. Therefore, since the sporting calendar is

not adapted for religious observances, and Muslim

soccer players continue to compete and train during

the month of Ramadan, various studies have examined

whether this religious fast has any effect on athletic

performance (for reviews, see Chaouachi et al., 2009c,

2012) and cognitive functions (Maughan, Fallah, &

Coyle, 2010; Waterhouse, 2010). It has been suggested

that few aspects of physical fitness are negatively

affected, and only modest decrements are observed

(Chaouachi et al., 2009c). The evidence to date

indicates that high-level athletes can maintain perfor-

mance during Ramadan if physical training, diet, and

sleep are well controlled. Nevertheless, despite this,

fasting athletes report higher fatigue at the end of

Ramadan (Chaouachi et al., 2009c; Guvenc, 2011).

The increased perception of fatigue reported during

Ramadan fasting and the combination of intense

training with altered carbohydrate intake, hydration

status, and sleeping disturbances may place fasting

Muslim athletes at greater risk of overreaching or

overtraining during Ramadan (Chaouachi et al.,

2009a, 2009b), which can result in physical injury,

especially overuse injuries (Johnson & Thiese, 1992).

Most previous studies have addressed whether the

holy month of Ramadan has any detrimental impact

on performance and cognitive functions. To our

knowledge, no study has examined the effect of this

religious fast on injury rates in athletes. Therefore, we

present some data from a pilot study that investigated

the injury rate during Ramadan in a professional

soccer squad over two consecutive competitive

seasons by comparing the injury rates between fasting

and non-fasting players within the same team.

Methods

Participants

Training loads, Hooper’s index (Hooper & Mack-

innon, 1995), and injuries were monitored in 42

professional soccer players (age 24 + 4 years; height

Soccer injury rates during Ramadan S95

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185 + 8 cm; body mass 78 + 4 kg) over two

consecutive seasons. This group included players

who were in the team for only a few months, i.e.

those who were transferred in or out of the team. A

high rate of player turnover explains the relatively

high number of players who were monitored in the

present study. All members of the squad were

monitored during the study period, i.e. one month

before Ramadan, the month of Ramadan, and the

month after Ramadan during each of the two

seasons. Goalkeepers were included in the study.

The studied team was competing at the highest

level in the Tunisian first league and also participated

in the African Cup of teams (CAF Cup) during the

second season of the study. Fasting status was

determined only at the end of the Ramadan month

via a personal interview with each player and discrete

cross-checking with the player’s team-mates and

whenever possible with family members and/or

friends. Based on this information, the players were

retrospectively organized into fasting and non-fasting

groups. The fasting group consisted of all players

who fasted throughout the Ramadan month and the

non-fasting group consisted of players who opted not

to fast throughout the Ramadan month for both

training and match days. All Muslim players who

fasted in this study had practised the fast during

Ramadan for at least the previous 7 years. The

players were not aware of the study objectives. All

players provided written informed consent and the

study’s procedures were approved by the Clinical

Research Ethics Committee of the National Centre

of Medicine and Science in Sports (Tunis, Tunisia).

Study design

The study focused on the month of Ramadan for two

consecutive seasons (i.e. from 10 August to 11

September 2010 and from 1 to 30 August 2011)

where the daily fast occurred from * 04.00 h to *19.15 h, for a total duration of * 15 h and 15 min.

During the study, both fasting and non-fasting

players underwent an identical training programme

under the supervision of the coaching staff and the

principal investigator of the study. Goalkeepers

(n ¼ 4 or 5, depending on the period of the season)

had their own training programme that was not

monitored by ratings of perceived exertion (RPE)

and Hooper’s index. Training data were collected

during the 12 weeks of pre-season and the start of the

competitive season, from July to October in each of

the 2 years, thus including the month of Ramadan in

both seasons. During these periods, the team

participated in local league and continental games

based on a classical one-game-a-week schedule. All

field players were monitored for 4 weeks before

Ramadan, the month of Ramadan (4 weeks), and 4

weeks after Ramadan in each year. During Ramadan,

training sessions and matches were performed after

dusk (starting at 22.00 h), while before and after

Ramadan the sessions and matches were scheduled

in the afternoon (starting at 15.00 or 16.00 h) and

sometimes in the morning for training (for the days

in which two training sessions were scheduled,

starting at 09.30 h). Ambient temperature, atmo-

spheric pressure, and relative humidity were mea-

sured for each training session (Figure 1).

Injury rate

Injury data were considered when a player was unable

to take full part in future soccer training sessions or

matches owing to physical complaints (Fuller et al.,

2006). Information about the circumstances (training

or match injury) and mechanism of injury (traumatic

or overuse injury) were recorded. The same team

doctor diagnosed all injuries, and an injured player was

considered injured until the team doctor cleared him

to participate in full training or matches. The durations

of training sessions (in the gym and on the field of play)

and matches for each player were precisely recorded.

Figure 1. (A) Ambient temperature (8C), (B) atmospheric pressure

(mmHg), and (C) relative humidity (%) before, during, and after

Ramadan. ¤ , 2010; &, 2011.

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Injury rates (training, match, overall) were calculated

as injuries per 1000 h of exposure.

Monitoring of training loads

Daily individual training load was calculated using

Foster’s session-RPE procedure (Foster et al., 2001).

This method involves multiplying the training dura-

tion in minutes by the mean training intensity. The

session-RPE scale is based on the Borg category ratio

(CR-10) RPE scale as modified by Foster et al.

(2001), which translates the player’s perception of

effort into a numerical score between 0 and 10. This

method has further been validated in soccer by

Impellizzeri and colleagues (Impellizzeri, Rampinini,

Coutts, Sassi, & Marcora, 2004). The player is asked

to respond to a simple question – How was your

workout? – with the aim of obtaining an uncompli-

cated response that reflects the athlete’s global

impression of the workout. All players had been

familiarized with this scale for at least one month

before the start of the study and followed standardized

instructions for session-RPE. Each player’s session-

RPE was collected approximately 20–30 min after

each soccer training session and match to ensure that

the perceived exertion referred to the whole training

session and match rather than the most recent (end-of-

session) exercise intensity (Impellizzeri et al., 2004).

Monitoring overtraining

Overtraining syndrome was monitored by Hooper’s

Index (Hooper & Mackinnon, 1995). This method is

based on self-analysis questionnaires involving well-

being ratings relative to fatigue, stress, delayed-onset

muscle soreness (especially ‘‘heavy’’ legs), and sleep

quality/disorders (Hooper & Mackinnon, 1995).

Before each training session and match, the players

were asked to rate subjective quality of sleep, and

quantity of stress, delayed-onset muscle soreness,

and fatigue on a scale of 1–7 in accordance with

Hooper and Mackinnon (1995). Hooper’s Index is

the sum of the four subjective ratings.

Statistical analysis

Data are expressed as means and standard deviations

(s). Two-way analysis of variance (ANOVA) was

used to compare differences between periods (before

Ramadan, during Ramadan, and after Ramadan) in

weekly training load, strain, duration, and environ-

mental conditions (temperature, humidity, and

atmospheric pressure). Multivariate analysis of var-

iance (MANOVA) was used to compare differences

between groups (fasting and non-fasting) and peri-

ods (before Ramadan, during Ramadan, and after

Ramadan) in Hooper’s Index, sleep, stress, delayed-

onset muscle soreness, and fatigue. Significant

differences in injury rates between periods were

assumed if the 95% confidence intervals (CI) did not

overlap. Significant differences in injury rates be-

tween fasting and non-fasting players were assumed

if the 95% confidence intervals (CI) did not overlap.

Statistical significance was set at P 5 0.05.

Results

Two-way ANOVA showed no significant differences

between the three periods (before Ramadan, during

Ramadan, after Ramadan: F ¼ 1.05, P 4 0.05) in

weekly training load, strain, duration, and environ-

mental conditions (temperature, humidity, and

atmospheric pressure) (Table I).

The MANOVA showed a significant difference

between fasting and non-fasting groups (F ¼ 4.79,

P 5 0.01) in Hooper’s Index and stress. No

significant differences were observed between the

three periods (P 4 0.05) for Hooper’s Index, sleep,

stress, delayed-onset muscle soreness, and fatigue for

both groups. No significant interaction was observed

between periods and groups (P 4 0.05). Indepen-

dent samples t-test showed that, compared with non-

fasting players, fasting players had significantly lower

(P 5 0.05; Table II) Hooper’s Index and stress

during and after Ramadan. When asked about the

timing of their sleep, players of both groups reported

not going to bed before 03.00 h due to late training

sessions and family, and socio-cultural and/or

religious events during the whole month of

Ramadan.

Overall injury rate and corresponding rates in the

whole squad are presented in Table III. Significantly

higher rates of non-contact injuries and overuse

injuries during training were observed in fasting

players during Ramadan, compared with before and

after the holy month (Table IV). No significant

Table I. Comparisons of weekly training load, strain, and duration (mean of the two seasons monitored and standard deviations)

Before Ramadan* Ramadan* After Ramadan*

Weekly training load (AU) 2045 (314) 1757 (558) 1807 (440)

Weekly training strain (AU) 2492 (634) 2525 (1826) 1839 (586)

Weekly training duration (min) 487 (73) 419 (130) 422 (109)

*Each period consisted of 4 weeks in each year. AU ¼ arbitrary units.

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differences were found between fasting and non-

fasting players in total injury rates.

The overall number of injuries for the two seasons

combined was 9, 19, and 9 injuries for before, during,

and after Ramadan, respectively. This gives a mean of

4.5 injuries for each of the two 4-week periods either

side of Ramadan, and a mean of 9.5 injuries during

the month of Ramadan. For each season, the overall

number of fasting and non-fasting players who were

injured was 12 and 5 for 2010, and 6 and 5 for 2011,

respectively. Of these players, only one goalkeeper got

injured in a traumatic training injury (ankle sprain).

For comparison purposes, the injuries of the team

over a period of 88 weeks, from 1 June 2010 to 19

February 2012 (*22 months, including both months

of Ramadan), resulted in a total of 121 injuries with

monthly rates as displayed in Table V. Total injuries

over the two study periods (before, during, and after

Table III. Overall numbers of injuries and corresponding rate for the whole squad in the two seasons

2010 season 2011 season Mean of two seasons

Number

of injuries

Injury rate (injuries

per 1000 h exposure)

Number

of injuries

Injury rate (injuries per

1000 h exposure)

Injury rate (injuries per

1000 h exposure)

Before Ramadan 7 7.6 2 2.3 4.9

Ramadan 12 13.8 7 10.9 12.3

After Ramadan 4 4.3 5 9.1 6.7

Table II. Comparison of Hooper Index (sleep, stress, delayed-onset muscle soreness, and fatigue) (mean of the two seasons monitored and

standard deviations)

Before Ramadan* Ramadan* After Ramadan*

Fasting Non-fasting Fasting Non-fasting Fasting Non-fasting

Hooper’s Index 9.8 (2.0) 11.6 (3.7) 10.5 (1.1)a 12.1 (1.2) 10.0 (0.6)a 11.3 (1.6)

Sleep 2.3 (0.6) 2.5 (0.8) 2.6 (0.2) 2.7 (0.3) 2.4 (0.4) 2.5 (0.5)

Stress 2.0 (0.3) 3.0 (1.5) 2.1 (0.3)a 3.1 (1.0) 1.9 (0.2)a 2.8 (1.1)

Delayed-onset

muscle soreness

2.6 (0.6) 2.9 (0.8) 2.9 (0.4) 3.2 (0.3) 2.7 (0.3) 2.9 (0.2)

Fatigue 2.9 (0.6) 3.2 (0.7) 3.1 (0.5) 3.4 (0.3) 3.0 (0.4) 3.2 (0.3)

*Each period consisted of 4 weeks in each year.aSignificantly different from non-fasting players (P 5 0.05).

Table IV. Comparisons of injury rates in fasters and non-fasters for the two seasons monitored

Before Ramadan* Ramadan* After Ramadan*

Fasting Non-fasting Fasting Non-fasting Fasting Non-fasting

Injury rate 3.3 (0–6.8) 1.7 (0–5.2) 8.1 (4.5–11.6) 3.9 (0.3–7.4) 4.5 (0.9–8.1) 1.6 (0–5.1)

Rate of contact injury 2.7 (0–6.3) 1.1 (0–4.7) 1.3 (0–4.9) 0.7 (0–4.3) 3.4 (0–7.0) 1.6 (0–5.1)

Rate of non-contact injury 0.6 (0–3.3) 0.6 (0–3.3) 6.8a (4.0–9.5) 3.2 (0.4–5.9) 1.1 (0–3.9) 0 (0–2.8)

Rate of contact injury

during matches

1.6 (0–4.1) 1.1 (0–3.5) 0.7 (0–3.2) 0.7 (0–3.2) 2.1 (0–4.5) 0 (0–2.4)

Rate of overuse injury

during matches

0 (0–1.3) 0 (0–1.3) 1.2 (0–2.4) 0 (0–1.3) 0.5 (0–1.8) 0 (0–1.3)

Rate of contact injury

during training

1.1 (0–3.1) 0 (0–2.0) 0.6 (0–2.6) 0 (0–2.0) 1.3 (0–3.3) 1.6 (0–3.5)

Rate of overuse injury

during training

0.6 (0–2.2) 0.6 (0–2.2) 5.6a (4.0–7.2) 3.2 (1.5–4.8) 0.5 (0–2.2) 0 (0–1.6)

*Each period consisted of 4 weeks in each year.a Significantly higher than before and after Ramadan (P 5 0.05).

Note: Values in bracket are 95% confidence intervals.

S98 K. Chamari et al.

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Ramadan) showed that 5 of 9 injuries before

Ramadan, and 4 of 9 injuries after Ramadan, were

sustained during matches, whereas only 4 of 19 were

sustained during matches during Ramadan. More-

over, overuse injuries were lower during the months

just before and after Ramadan with only 2 of 9 injuries

in both cases, while this type of injury dramatically

increased during Ramadan with 16 overuse injuries

out of a total of 19 injuries observed for the two

months of Ramadan monitored. For these two

Ramadan months, the 16 non-contact injuries were

distributed as follows: 7 muscle spasms (contrac-

tures), 7 tendinosis, and 2 muscle strains (one tear at

the hamstrings and one strain at the thigh-adductors).

The 7 contractures were located at the hamstrings

(n ¼ 3), foot flexors (n ¼ 2), thigh-adductors

(n ¼ 1), and knee extensors (n ¼ 1). The 7 tendinosis

injuries were located at the thigh-adductors (n ¼ 3)

and foot flexors (n ¼ 1), with the remaining 3 located

at the abdomen and pelvis.

Discussion

The aim of this study was to examine the effects of

the month of Ramadan and its specific socio-cultural

and religious environment on the injury rates of

professional elite soccer players over two consecutive

seasons. The main findings of this study were the

absence of any significant difference between fasting

and non-fasting players with respect to general injury

rates, while the non-contact and training overuse

injury rates were significantly higher during than both

before and after Ramadan for fasting players. Never-

theless, these groups showed differences for Hooper’s

Index and perceived stress, with fasting players having

lower Hooper’s Index and stress during and after

Ramadan than non-fasting players. Moreover, no

difference was observed between fasting and non-

fasting players for the reported quality of sleep, and

quantity of delayed-onset muscle soreness and fatigue

before, during, and after Ramadan. Training load,

training strain, and duration were not significantly

different between the three periods or between groups

for the two monitored seasons.

Some recent work has suggested that elite athletes

could avoid marked decrements in their physical

capacities while undergoing the intermittent fast of

Ramadan, when they were maintaining their usual

training loads; rather, most measured fitness vari-

ables were maintained at their pre-Ramadan values

(for a review, see Chaouachi et al., 2009c). Conse-

quently, the technical staffs of the soccer team in the

present study chose not to decrease training load

during Ramadan for the two seasons studied.

Although not objectively measured, the team’s

fitness remained at a relatively high level of competi-

tiveness and the team kept qualifying for the African

Cup of teams (CAF Cup). Even if not involved in a

congested match fixture, and the fact that the general

injury rate was not altered, the non-contact and the

training overuse injuries were significantly increased

in fasting players during Ramadan.

The injury rates of the present study (Tables III

and V) were consistent with data reported for the

Union of European Football Associations (UEFA)

(Ekstrand et al., 2011), English Premier League

(Hawkins et al., 2001), Swedish Premier League

(Hagglund et al., 2006), Scottish league (Dupont

et al., 2011), and Norwegian league (Andersen et al.,

2004). Ekstrand et al. (2011) reported a rate of 8.0

injuries per 1000 h for 23 first team squads selected by

UEFA as belonging to the 50 best European teams for

seven consecutive seasons (i.e. 2001 to 2008). The

results of the present study are also consistent with the

data of Hawkins et al. (2001), who reported an

average of 1.3 injuries per player per season in the

English Premier League. In the Swedish Premier

League, Hagglund et al. (2006) prospectively re-

corded individual exposure and time-loss injuries

over two full consecutive seasons (2001 and 2002).

They showed that training and match injury inci-

dences were similar between seasons (5.1 vs. 5.3

injuries per 1000 training hours and 25.9 vs. 22.7

injuries per 1000 match hours). In elite Scottish

soccer, Dupont et al. (2011) reported similar injury

rates for one-game-a-week with an overall injury rate

of 4.1 injuries per 1000 h of exposure, which was

composed of 2.5 injuries per 1000 h of training and

19.3 injuries per 1000 h of match-play. In a prospec-

tive study in Norway, Andersen et al. (2004) collected

videotapes and injury information for the regular

league matches of the Norwegian season (April

Table V. Monthly injury rate (for each 4-week period) for the studied team over 88 weeks (*22 months)

Mean s Min. Max.

Number of injuries per 4-week periods (n) 5.5 2.7 0.0 10.0

Volume of training and matches (h) 29.2 5.0 20.0 39.9

Number of players in the squad (n) 28.7 1.7 26.0 32.0

Total monthly training and match exposure (h) 844.1 179.1 520.4 1276.8

Injury rate (injury per 1000 h exposure) 6.9 3.7 0.0 17.3

Soccer injury rates during Ramadan S99

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through October 2000). During 174 matches, 425

incidents were recorded, that is, 1.2 incidents per

team per match or 75.5 incidents per 1000 playing

hours. A total of 121 acute injuries were reported from

the same matches, that is, 0.3 injuries per team per

match or 21.5 injuries per 1000 playing hours. In this

regard, the injury rate of the present study outside the

month of Ramadan is lower than that generally

reported in the literature. It should be stressed that

this injury rate relates to pre-season and the start of the

season, which might explain these lower rates. Pre-

season is characterized by a high prevalence of

endurance training and fitness training, which were

performed in the present study in a progressive

manner. The low frequency of matches at these stages

might be the cause of the low overall injury rates of the

studied periods. In this context, it has been well

demonstrated that match injury rates are always much

higher than training injury rates. Moreover, Koute-

dakis and Sharp (1998) showed that the preparation

phase of the season is accompanied by fewer injuries

than the competition phase. Despite a higher mean

overall injury rate during the month of Ramadan in

the two studied seasons (i.e. 12.3 injuries per 1000 h

exposure vs. 4.9 for before Ramadan and 6.7 for after

Ramadan), the differences were not significant.

Nevertheless, the rate of overuse and non-contact

injuries during training found in the present study was

significantly higher during than both before and after

Ramadan in fasting players (Table IV). As this

increase in injury rate was observed in fasting players,

the Ramadan fasting-induced hypohydration hypoth-

esis might explain this result (Huffman, Yard, Fields,

Collins, & Comstock, 2008; for a review on hydration,

see Maughan & Shirreffs, 2012). As hydration status

was not monitored, it remains possible that both

groups’ players were relatively hypohydrated during

Ramadan fasting especially during daylight hours.

Even if the reported quality of overall sleep was not

altered during Ramadan, the sleeping scheduling was

greatly modified with players not going to bed before

03.00 h. Recently, Luke et al. (2011) showed that

sleeping less than 6 h the night before an injury

occurred was associated with an increase in fatigue-

related injuries (P ¼ 0.028). The results of the

present study show no influence of Ramadan on

the perceived sleep quality of the participants. As

Hooper’s Index is a simple general index that

assesses sleep quality, the absence of change does

not necessarily mean that sleep architecture was not

altered. Even if the participants were generally

satisfied about their whole 24-h sleep quality, it

may be that the time spent in the different sleeping

phases was modified. In this context, it has been well

established that sleeping architecture is characterized

by different phases at the beginning and the end of

the night (Czeisler, Weitzman, Moore-Ede,

Zimmerman, & Knauer, 1980; Duffy, Kronauer, &

Czeisler, 1996). The change in sleeping and nutri-

tional habits during Ramadan (i.e. much less night-

sleep and more afternoon naps for fasters and non-

fasters and major changes in eating patterns for the

fasting players) may have altered the players’

physiological status during Ramadan, probably lead-

ing to the observed higher overuse injury rate during

the fasting month (Bogdan, Bouchareb, & Touitou,

2001; Montelpare, Plyley, & Shephard, 1992; Reilly

& Waterhouse, 2007). (For a review of sleep

disturbances effects, see Roky, Herrera, and Ahmed,

2012.) After sleep architecture disturbances, another

possible cause of higher overuse injuries could also

be the end of Ramadan state of the fasting players.

Chaouachi et al. (2009b) have clearly shown that

elite athletes continuing to complete high training

loads during Ramadan often endure higher levels of

fatigue and are likely to experience a cascade of small

biochemical adjustments, including hormonal, im-

munoglobulin, and antioxidant system changes, and

an elevated inflammatory response. These variations

are close to what is observed in tissue traumatic

processes as found in athletes in an over-reaching or

overtraining state (Chaouachi et al., 2009b).

Although the variations are small and may not be

considered clinically relevant, they may still signal

physiological stress (Chaouachi et al., 2009b). In this

context, the overtraining syndrome has been referred

to as staleness or chronic fatigue with mental

weariness along with some associated injuries that

are observed in parallel with a significant decline in

physical performance (Halson & Jeukendrup, 2004;

Kentta & Hassmen, 1998). Overtraining affects the

musculoskeletal system in that serum creatine kinase

levels are increased and enzymatic markers of muscle

tissue injury significantly elevated the day after high

training loads. It is unclear whether the observed

overuse injuries observed in the overtrained or over-

reached athlete could be the result of excessively high

training loads and/or the impaired ability to recover

from training.

At odds with many studies (for a review see

Chaouachi et al., 2009c) showing that Ramadan

induces additional stress on the athlete, the stress

assessed by the Hooper Index during Ramadan in the

present study was not different from stress measured

before and after Ramadan for non-fasting players.

Nevertheless, the fasting players reported decreased

stress for Ramadan and for the month after Ramadan.

It could be speculated that the religious beliefs and the

well-being of living and practising a holy month could

have led to a lower perception of stress in the fasting

players. The possible habituation process in the

fasting players has also to be considered, as they

reported that they had fasted and trained simulta-

neously for 7 years and thus the absence of total injury

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risk with respect to non-fasting players relates to

habituated fasters. Newly fasting players’ data are not

available from the present study.

Conclusion

Several changes that occur during Ramadan fasting

may potentially affect the injury risk for fasting

players. In Muslim majority countries, non-fasting

players may also be affected by changes in eating and

sleeping habits and in the scheduling of training and

match-play. Preliminary data, however, show the

absence of an effect of the holy month of Ramadan

on the general injury rates of fasting and non-fasting

elite soccer players where weekly training loads were

maintained during Ramadan. However, rates of non-

contact injuries and rates of overuse injuries during

training were higher during than both before and

after Ramadan in fasting players.

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