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مرکز اطلاعات علمی SID1
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
Writer: 

STANNARD STEPHEN R.

Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    127
  • End Page: 

    133
Measures: 
  • Citations: 

    0
  • Views: 

    16622
  • Downloads: 

    10064
Keywords: 
Abstract: 

Fasting induces short-term physiological adaptations which spare the body’s remaining carbohydrate stores and mobilize lipid stores to provide a substitute fuel for many tissues and organs, especially skeletal muscle. Rodent studies show that regular occurrence of fasting then refeeding, stimulates adaptations in muscle which make the animal better placed to withstand a further period of fasting by possessing a better ability to oxidise lipid.This review explores the research describing these adaptations, with an emphasis on Ramadan, a human model of repeated fasting/refeeding. Separately, a single bout of endurance exercise places similar metabolic stress on the body as fasting since the exercising muscle must reduce its use of carbohydrate and utilize lipid more readily as exercise progresses. Not surprisingly therefore, adaptations in muscle to repeated bouts of endurance exercise (endurance training) are similar to those seen with repeated fasting/refeeding. Superimposing the stressors of repeated fasting/refeeding and exercise training, and subsequent adaptations to the muscle and exercise response, are examined by describing the published research which has investigated the situation where athletes continue their training whilst participating in Ramadan.

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    134
  • End Page: 

    144
Measures: 
  • Citations: 

    0
  • Views: 

    19104
  • Downloads: 

    12531
Keywords: 
Abstract: 

Purpose: The aim of this study was to assess the effects of Ramadan fasting on several biochemical and anthropometric parameters in physically active men by comparing fasters and nonfasters before, during, and after Ramadan.Methods: Eighteen physically active men (10 fasters and 8 nonfasters) participated in this study. Subjects visited the laboratory for a total of four sessions on the following occasions: three days before Ramadan (Bef-R), the 15th day of Ramadan (Mid-R), the 29th day of Ramadan (End-R), and 21 days after Ramadan (Post-R). During each session, subjects underwent anthropometric measurements, completed a dietary questionnaire and provided a fasting blood sample.Results: Body weight and body fat percentage decreased in fasters by 1.9% (P<0.001) and 6.2% (P=0.003), respectively, but increased in nonfasters by 2.2% (P<0.001) and 10.2% (P=0.001), respectively, from Bef-R to End-R.Fasters’ hematocrit and hemoglobin increased by 5.3% (P<0.001) and 6.3% (P=0.01), respectively, from Bef-R to End-R, while neither of these parameters changed in nonfasters. Fasters experienced an increase in the following parameters from Bef-R to End-R: urea (8.7%, P<0.001), creatinine (7.5%, P<0.001), uric acid (12.7%, P<0.001), serum sodium (1.9%, P<0.001), serum chloride (2.6%, P<0.001) and high-density lipoprotein cholesterol (27.3%, P<0.001). Of these parameters, only creatinine increased (4.4%, P=0.01) in nonfasters.Conclusions: We conclude that Ramadan fasting lowers body weight and body fat percentage and can elevate high-density lipoprotein cholesterol in physically active men. However, practicing aerobic exercise during a hot and humid Ramadan month can induce a state of dehydration marked by an increase in some renal function markers and serum electrolytes.

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    145
  • End Page: 

    153
Measures: 
  • Citations: 

    0
  • Views: 

    15325
  • Downloads: 

    11435
Abstract: 

Purpose: Our study aimed to profile the effect of fasting during the Ramadan month on cognitive function in a group of healthy Muslim athletes.Methods: Eighteen male athletes underwent computerized neuropsychological testing during (fasting) and after (non-fasting) Ramadan. Diet was standardized, and tests were performed at 0900h and 1600h to characterize potential time-of-day (TOD) interactions. Psychomotor function (processing speed), vigilance (visual attention), visual learning and memory, working memory (executive function), verbal learning and memory were examined. Capillary glucose, body temperature, urine specific gravity, and sleep volume were also recorded.Results: Fasting effects were observed for psychomotor function (Cohen’s d=1.3, P=0.01) and vigilance (d=0.6, P=0.004), with improved performance at 0900h during fasting; verbal learning and memory was poorer at 1600h (d=-0.8, P=0.03). A TOD effect was present for psychomotor function (d=-0.4, P<0.001), visual learning (d=-0.5, P=0.04), verbal learning and memory (d=-1.3, P=0.001), with poorer performances at 1600h. There was no significant fasting effect on visual learning and working memory.Conclusions: Our results show that the effect of fasting on cognition is heterogeneous and domain-specific. Performance in functions requiring sustained rapid responses was better in the morning, declining in the late afternoon, whereas performance in non-speed dependent accuracy measures was more resilient.

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    154
  • End Page: 

    160
Measures: 
  • Citations: 

    0
  • Views: 

    10945
  • Downloads: 

    8142
Keywords: 
Abstract: 

Purpose: The purpose of this study was to examine the effects of Ramadan fasting on circulating levels of interleukin-12 (IL-12) after a brief maximal exercise.Methods: Nine subjects performed a Wingate test on three different occasions: (i) the first week of Ramadan (1WR), (ii) the fourth week of Ramadan (4WR), and (iii) three weeks after Ramadan (AR). Blood samples were taken before, immediately and 60 min after the exercise.Plasma concentrations of IL-12 were measured using enzyme-linked immunosorbent assay. Variance analysis revealed no significant effect of Ramadan on Ppeak and Pmean during the three testing periods.Results: Considering the effect of Ramadan on plasma concentrations of IL-12, analysis of the variance revealed a significant Ramadan effect (F (2, 16) =66.27, P<0.001) as well as a significant time effect (F (2, 16)=120.66, P<0.001). However, no significant (Ramadan×time) of test interaction (F (4, 32) =2.40, P>0.05). For all measures, IL-12 levels were lower during 1WR and 4WR in comparison with AR (P<0.05). Considering the exercise effects, IL-12 levels measured immediately after the exercise were significantly higher than those measured before and at 60 minutes after the exercise (P<0.001).Conclusions: These results suggest that an acute intense exercise induced IL-12 response is modified by daytime fasting and modifications in sleep schedule during Ramadan.

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    161
  • End Page: 

    166
Measures: 
  • Citations: 

    352
  • Views: 

    15618
  • Downloads: 

    11027
Keywords: 
Abstract: 

Purpose: The aim of this study was to determine the effect of Ramadan fasting on body composition, calorie intake and physical performance in young female athletes undertaking training sessions during Ramadan.Methods: Twelve voluntary female athletes (15-27 years old) were assigned to the research. A prospective study was conducted to investigate the athletes on four different occasions: one week before Ramadan (T1), the second (T2) and fourth (T3) weeks of Ramadan, and two weeks after the end of Ramadan (T4). Food intake, body composition and physical performance (agility, balance and explosive leg power) were investigated on each occasion. Further, Physical performance was assessed by agility, vertical jump and balance tests.Results: There was a significant main effect for time for body composition indices. A significant decrease was observed in weight (P=0.01) and body mass index (BMI) (P=0.01) in T2 compared with T1, further decrease in weight (P<0.001) and BMI (P<0.001) was observed in T3 compared to T1. Calorie intake decreased significantly in T3 compared with T1 (P=0.008), and increased significantly in T4 compared with T3 (P=0.04). There was a significant main effect for time for agility performance (P=0.03), but no significant main effect for time was observed for vertical jumping (P=0.1) and balance performance (P=0.3).Conclusions: This study has found that Ramadan fasting could affect the body composition, but not physical performance in female athletes during Ramadan.

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    167
  • End Page: 

    176
Measures: 
  • Citations: 

    0
  • Views: 

    14549
  • Downloads: 

    8622
Abstract: 

Purpose: To examine the subjective perception of daily acute fasting on sports performance, training, sleep and dietary patterns of Muslim athletes during the Ramadan month.Methods: Seven hundred and thirty-four (411 male and 323 female) Malaysian Junior-level Muslim athletes (mean age 16.3±2.6 y) participated in the survey which was designed to establish the personal perception of their sport performance, sleep pattern, food and fluid intake during Ramadan fasting. The survey was conducted during and immediately after the month of Ramadan in 2009.Results: Twenty-four percent of the athletes perceived that there was an adverse effect of the Ramadan fast on their sporting performance and 29.3% reported that quality of training during Ramadan was also negatively influenced. Majority (48.2%) of the athletes stated that Ramadan fasting did not affect their normal sleep pattern but 66.6% of them complained of sleepiness during the daytime. Half of the athletes (41.4%) maintained the caloric intake during Ramadan as they normally would with the majority of them (76.2%) reporting that they consumed more fluids during Ramadan.Conclusions: Overall, Malaysian Junior-level Muslim athletes showed diverse views in their perception of changes in their training, sleep and dietary patterns during Ramadan fast. These individual differences probably indicate differences in the athletes’ adaptability and coping strategies during fasting and training in Ramadan.

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    177
  • End Page: 

    185
Measures: 
  • Citations: 

    352
  • Views: 

    18879
  • Downloads: 

    11466
Keywords: 
Abstract: 

Purpose: This study was designed to assess the effects of Ramadan fasting on the profile of mood state and perceived exertion in young soccer players and aerobic and anaerobic performances during the Yo-Yo, repeated sprint ability (RSA) and the Wingate tests.Methods: Twenty junior male soccer players completed the Yo-Yo, the RSA, and the Wingate tests on three different occasions: one-week before Ramadan (BR), the second week (SWR) and the fourth week (ER) of Ramadan. The total distance (TD) covered and the estimated maximal aerobic velocity (MAV) during the Yo-Yo test were recorded. During the RSA test, peak power (PP) during each sprint, the percentage of decrement of PP (PD) and total work (Wtotal) were calculated. During the Wingate test, peak (Ppeak) and mean (Pmean) powers and fatigue index (FI) were recorded.Results: TD and MAV (P=0.01) during the Yo-Yo test and PP (P=0.01, P=0.004, P=0.001, P=0.01, P=0.03 for sprints 1, 2, 3, 4, and 5, respectively) and Wtotal (P=0.02) during the RSA test were significantly higher during BR than ER. Furthermore, muscle fatigue during the RSA test increased significantly from BR to ER (P=0.01). Ppeak and Pmean during the Wingate test decreased significantly from BR to SWR and ER (P<0.0005). FI was higher during SWR (P=0.001) and ER (P<0.0005) than BR. In addition, rating of perceived exertion scores and fatigue estimated by the profile of mood state questionnaire were higher during Ramadan in comparison with BR.Conclusions: The present study suggests that both aerobic and anaerobic performances during the Yo-Yo, the RSA and the Wingate tests were affected by Ramadan fasting in young soccer players.

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    186
  • End Page: 

    194
Measures: 
  • Citations: 

    0
  • Views: 

    17641
  • Downloads: 

    10223
Abstract: 

Purpose: To evaluate the effect of Ramadan fasting on body water status markers of rugby players at basal condition and following a simulation of rugby sevens match.Methods: Twelve recreational rugby sevens players played three matches: one day before Ramadan (before Ramadan), at the end of the first week of Ramadan (Beg-R) and at the end of Ramadan (End-R). Before and immediately after each match, body weight was determined and blood samples were taken for the measurement of body water status markers. Total body water was measured with an impedancemeter only before matches.Results: At rest, an increase in hematocrit (+4.4%, P=0.03), hemoglobin (+3.4%, P=0.01) and plasma osmolarity (+2.8%, P<0.001) was noticed at End-R compared to before Ramadan. Total body water measured before Ramadan did not differ significantly from that of Ramadan. After the match, values of hematocrit and plasma osmolarity increased significantly at End-R (+1.4%, P=0.02; +3.1%, P<0.001 respectively) compared to before Ramadan. Although, hemoglobin measured after matches occurring during Ramadan did not differ from those of before Ramadan. In response to matches, the change of percentage of body water status markers did not differ during each period of the investigation.Conclusions: The present results show that Ramadan fasting induces dehydration at basal conditions. Also, rugby sevens match played during Ramadan did not exacerbate the magnitude of responses to matches of blood and body water status markers.

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    195
  • End Page: 

    204
Measures: 
  • Citations: 

    0
  • Views: 

    12339
  • Downloads: 

    7461
Keywords: 
Abstract: 

Purpose: Some major competitions (e.g. London Olympics, 2012) are scheduled during the Ramadan fasting month. Little attention has been given to explore the archers’ performance related subjective experiences with a qualitative method. Therefore, this study addressed individual archers’ subjective experiences within the framework of self-regulation during Ramadan.Methods: Eleven elite Malaysian Muslim fasting archers volunteered toparticipate in the study. Grounded theory was the qualitative approach used to examine the subjective experiences of athletes during Ramadan. Interviews were conducted and inductive content analysis was adopted to identify the temporal patterns of self-regulation of subjective experiences across the fasting period. Results: Inductive content analysis identified (a) physical, (b) mental, (c) emotional, (d) behavioral, and (e) spiritual experiences. Overall patterns revealed that experiences associated with physical, emotional, behavioral, and spiritual dimensions dominated in the first phase of fasting, while the mental dimension surfaced increasingly in the latter phase of fasting.Conclusions: The trend showed changes in the patterns of experiences among the major domains across the temporal dimension. Athletes reported increased subjective experiences in mental factors toward the latter half of the fasting period. Practitioners should emphasize on mental aspects of training, as these appear to be salient in archery performance.

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    2
  • Issue: 

    3
  • Start Page: 

    205
  • End Page: 

    210
Measures: 
  • Citations: 

    352
  • Views: 

    20612
  • Downloads: 

    8971
Keywords: 
Abstract: 

Purpose: Muslim athletes may continue training and competing while they are fasting. There is a concern about negative effects of fasting on sports performance. This study aimed to investigate the influence of two training time frames on athletes’ body composition and performance during Ramadan fasting.Methods: An observational study was conducted and thirty four male volunteer athletes from different sports including volleyball, karate, taekwondo and football were assigned in two groups. The first group included 14 elite athletes who during Ramadan voluntarily participated in training sessions at 1 hour before Iftar (BI) and the second group of 20 elite athletes who during Ramadan participated in training sessions at 3 hours after Iftar (AI). Testing was performed one week before; in the first and fourth weeks of Ramadan and one week after Ramadan. Weights, heights and skinfold thickness were assessed at each time point and body mass index was calculated. Each player was assessed for agility and explosive strength as well.Results: The mean weight and body mass index of both groups decreased significantly during Ramadan (P<0.001). Performance variables were not negatively affected by fasting in BI or AI group athletes.Conclusions: Weight reduction might come with either BI or AI training schedules in Ramadan. Daytime or evening training did not inversely affect the agility and power performances in a group of elite athletes during Ramadan fasting.

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مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID
مرکز اطلاعات علمی SID