Ramadan intermittent fasting and its association with health-related indices and exercise test performance in athletes and physically active individuals: an overview of systematic reviews

OBJECTIVE

To systematically review, summarise and appraise findings of published systematic reviews, with/without meta-analyses, examining associations between Ramadan fasting observance (RO), health-related indices and exercise test performances in athletes and physically active individuals.

DESIGN

Overview of systematic reviews with assessment of reviews' methodological quality.

DATA SOURCES

PubMed, Web of Science, Scopus, Cochrane Database of Systematic Reviews, SPORTDiscus, ProQuest, PsycINFO and SciELO.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Systematic reviews with/without meta-analyses examining associations of RO with health-related indices and exercise performances in athletes and physically active individuals.

RESULTS

Fourteen systematic reviews (seven with meta-analyses) of observational studies, with low-to-critically-low methodological quality, were included. Two reviews found associations between RO and decreased sleep duration in athletes and physically active individuals. One review suggested athletes may experience more pronounced reductions in sleep duration than physically active individuals. One review found associations between RO and impaired sleep quality in athletes and physically active individuals. RO was associated with decreased energy, carbohydrate and water intake in adult-aged athletes, but not adolescents. One review suggests RO was associated with athletes' increased feelings of fatigue and decreased vigour. No association was found between RO and athletes' lean mass or haematological indices. RO was unfavourably associated with changes in athletes' performance during high-intensity exercise testing.

CONCLUSION

Continuance of training during RO could be associated with athletes' mood state disturbances, decreased sleep duration and performance decline during high-intensity exercise testing, while preserving lean mass. However, careful interpretation is necessary due to the low-to-critically-low methodological quality of the included reviews.

A single all-out bout of 30-s sprint-cycle performed on 5 consecutive days per week over 6 weeks does not enhance cardiovascular fitness, maximal strength, and clinical health markers in physically active young adults

BACKGROUND

This study examined the effects of a single all-out bout of 30-s sprint-cycle performed daily for 5 consecutive days per week for 6 weeks, on aerobic fitness, muscle strength and metabolic-health markers in physically active young males and females.

METHODS

Healthy, physically active 20-28 year olds, were randomly assigned to either experimental (EXP, N = 11) or non-training control (CON, N = 8) group. With supervision, the EXP group performed one bout of 30-s sprint-cycle daily, Mondays to Fridays over 6 weeks, while CON group continued with their usual lifestyle. The followings were measured at pre- and post-intervention: maximal aerobic power, peak torque of knee extensors and flexors at velocities 30° s-1 and 300° s-1, resting heart rate, resting blood pressure, body fat percentage, fasting lipid profile, fasting blood glucose, and fasting insulin levels.

RESULTS

There were no significant improvements in the EXP group for all the measured variables (all P > 0.05); except for significant interaction effects in peak torque of knee extensors at 30° s-1 (P = 0.044) and low-density lipoprotein-cholesterol (P = 0.046). Post hoc test indicate that CON group showed decline in their low-density lipo-proteins levels (P = 0.024).

CONCLUSION

Six weeks of one all-out bout of 30-s sprint-cycle per day, for 5 consecutive days per week, was ineffective in improving cardiovascular fitness, maximal strength, and most health markers in physically active young adults. The present results when combined with the previous literature suggest that there is a possibility of a minimum threshold for a number of sprint-cycle bouts needed to be performed before any form of cardio-metabolic-health benefit is accrued.

Effects of Isometric Strength and Plyometric Training on Running Performance: A Randomized Controlled Study

Purpose: The aim of the study was to compare the effects of isometric strength (IST) and plyometric training (PT) on endurance running performance. Methods: Twenty-six endurance runners (18 males and 8 females; age 36 ± 6 years, stature 1.69 ± 0.05 m body mass 61.6 ± 8.0 kg, VO_2max 50.4 ± 5.8 ml·kg^-1·min^-1) completed the countermovement jump (CMJ), isometric mid-thigh pull (IMTP), 2.4 km run time trial (2.4kmTT), running economy test (RE) and a graded exercise test measures at baseline. They were then randomly assigned to three groups, the control (CON), PT or IST group, and completed the circuit, plyometric or isometric training, respectively, twice a week for 6 weeks, while still continuing to perform their planned running training. They then completed the same set of measures performed at baseline post-intervention. Results: Significant time x group interactions and time main effect were observed for 2.4kmTT (P = .002, ƞ²_p = .45 and P < .001, ƞ² =0.72), maximal aerobic speed (MAS) (P = .006, ƞ²_p = .39), CMJ height (P < .001, ƞ²_p = .55) and IMTP relative peak force (P = .001, ƞ²_p = .50) in favor of PT and IST. Significant main effect for time was observed for 2.4kmTT (P < .001, ƞ²_p = .72), RE (P = .048, ƞ²_p = .17), VO_2max (P = .047, ƞ²_p = .18), MAS (P < .001, ƞ²_p = .63), CMJ height (P < .001, ƞ²_p = .51) and IMTP relative peak force (P < .001, ƞ²_p = .58). Conclusion: In conclusion, both PT and IST were similarly effective at enhancing running endurance performance. However, IST resulted in greater improvement to RE.

Aspetar clinical guidelines: Ramadan fasting and exercise for healthy individuals

Healthy adult Muslims who practice Ramadan fasting (RF) follow strict religious rules regarding their lifestyle. RF influences several parameters, including nutrition, hydration, and sleep habits, and can potentially reduce physical performance. It seems that RF prevents athletes from training and participating in competitions, and prevents the general community from engaging in physical exercise. This places practicing Muslim athletes at a competitive disadvantage. Therefore, the goal of this guide was to provide practical recommendations, based on expert panel consensus, for healthy athletes and their support staff on how to adopt appropriate behavioral, social, and psychological strategies to cope with the changes and constraints resulting from RF. The recommendations developed in this guide are not limited to prescribing appropriate exercise during the month of Ramadan (ie; schedule, frequency, intensity, duration, type of exercise, and training load), but cover different aspects of lifestyle such as nutrition, hydration, and sleep, and address psychosocial and cognitive aspects related to RF. These recommendations are intended for healthy individuals. Patients with chronic illnesses should refer to their doctor to ensure an eventual safe practice.

Assessing Physical Fitness of Athletes in a Confined Environment during Prolonged Self-Isolation: Potential Usefulness of the Test of Maximal Number of Burpees Performed in 3 Minutes

Due to a prolonged period of quarantine during the COVID-19 pandemic, it is essential to monitor the physical condition of athletes isolated at home with a fitness tool that measures various aspects of physical fitness, which does not require any special equipment, and can be performed within a small space. This study assessed the reliability and validity of the test of performing the maximal number of burpees in 3 min (or 3-MBT) to monitor strength, power, and aerobic endurance in trained athletes. For Part I (reliability of the 3-MBT), 20 (10 male, 10 female) national athletes from various sports performed the 3-MBT on two separate test sessions. Athletes performed as many burpees as possible within 3 min and the primary performance criteria was the number of burpees completed (where a higher number reflected a better performance). The 3-MBT displayed excellent relative reliability in the athletes, with an intraclass correlation coefficient (ICC) and coefficient of variation (CV %) of >0.92, and <3.0%, respectively. For Part II (validity of the 3-MBT), 40 (20 M, 20 F) athletes performed the 3-MBT, and the countermovement jump (CMJ), isometric mid-thigh pull (IMTP), seated medicine ball throw (SMBT), isometric bench (IBP) and maximal aerobic power (VO2max) tests on separate sessions. When data of male and female athletes were pooled, there were significant correlations between relative 3-MBT and relative CMJ height (r = 0.65, large; p < 0.001), relative IMPT peak force (r = 0.50, large; p < 0.001), relative IBP peak force (r = 0.36, moderate, p = 0.02), and relative VO2max (r = 0.50, large; p < 0.001). In conclusion, the 3-MBT is a reliable and reasonably useful test and is a valid assessment of lower body power and strength, upper body strength and aerobic fitness in trained male and female athletes.

Walking Football During Ramadan Fasting for Cardiometabolic and Psychological Health Benefits to the Physically Challenged and Aged Populations

Concurrent exercise and intermittent fasting regimens for long periods have been shown to enhance cardiometabolic health in healthy individuals. As exercise and fasting confer health benefits independently, we propose that Muslims who are fasting, especially those experiencing health and clinical challenges, continually engage in physical activity during the Ramadan month. In this opinion piece, we recommend walking football (WF) as the exercise of choice among Muslims who are fasting. WF can be played by any individual regardless of the level of fitness, skills, and age. WF has been shown to elicit cardiovascular and metabolic stress responses, which are suitable for populations with low fitness levels. Most importantly, WF has the inherent characteristics of being a fun team activity requiring social interactions among participants and, hence, likely to encourage long-term consistent and sustainable participation.

Effectiveness of On-Court Resistive Warm-Ups on Change of Direction Speed and Smash Velocity during a Simulated Badminton Match Play in Well-Trained Players

In badminton, power production can be enhanced through the fundamental practice of a dynamic warm-up with resistance conditioning activity to induce a post-activation performance enhancement (PAPE) effect. The use of heavy resistance exercise in the form of heavy weights to induce PAPE during competition is not logistically practical in the badminton arena. Thus, there is a need to investigate the use of easily available alternative preconditioning stimuli to induce a similar potentiating effect in badminton-specific performance. This study adopted a repeated-measures design of three warm-up conditions: control (CON), weighted wearable resistance (WWR), and resistance band variable resistance (BVR). Fourteen badminton players from the national training squad (11 males, 3 females, age 18 ± 1 y) completed the experimental sessions in random order. Change of direction speed (CODS) and smash velocity (SV) tests were performed at five timepoints-baseline test after the warm-up and at the end of each of the four exercise blocks of a simulated match play protocol. CODS was significantly faster under the two resistance warm-up conditions (WWR and BVR) compared to the CON condition at baseline (-0.2 s ± 0.39 and -0.2 s ± 0.46, p = 0.001 and 0.03, g = 0.47 and 0.40, respectively), but there were no differences at the other timepoints (all p > 0.05). SV was significantly faster for all the four exercise blocks than at baseline under all three warm-up conditions (p = 0.02), but there were no differences in SV between the three warm-up conditions across all the five measured timepoints (p = 0.15). In conclusion, implementing resistance (~10% body weight) in sport-specific plyometric exercises using WWR or BVR during warm-up routines may induce PAPE effects on the change of direction speed but not smash velocity, in well-trained badminton players, as compared with the same warm-up exercises using bodyweight (i.e., CON condition). The positive effects of CODS were, however, observed only at the start of the match and possibly lasted for up to between 5 and 10 min of match play.

Running Demands and Activity Profile of the New Four-Quarter Match Format in Men's Field Hockey

ABSTRACT

Ihsan, M, Yeo, V, Tan, F, Joseph, R, Lee, M, and Aziz, AR. Running demands and activity profile of the new four-quarter match format in men's field hockey. J Strength Cond Res 35(2): 512-518, 2021-This study determined the running demands of men's field hockey with regards to the revised four-quarter match format. Twenty-eight male field hockey players were equipped with global positioning system units while competing in 14 competitive international games over a 1-year period. All matches allowed for unlimited substitutions, and consisted of four 15-minute quarters (i.e., Q1-Q4). A progressive decline in total distance (TD) was observed in Q2 (2,072 ± 141 m) to Q4 (2,055 ± 212 m) compared with Q1 (2,171 ± 195 m, p < 0.05). However, the decline in TD was due to decreases in low-intensity activity (<15 km·h-1, p < 0.05), as high-intensity running (HIR; >15 km·h-1) distances were similar throughout Q1-Q4 (p = 0.263). Positional data demonstrated a similar profile, where significant decreases in TD, but not in HIR, was observed across all playing positions at some point over the 4 quarters (p < 0.05). DEF accumulated the lowest amount of TD (7,631 ± 753 m), HIR (2,257 ± 498 m), and high-intensity decelerations (60 ± 9, >-2m·s-2) compared with MID and FWD (p < 0.05). By contrast, FWD performed the highest amount of HIR (3,090 ± 565 m) and high-intensity accelerations (110 ± 9, >2 m·s-2) compared with MID and DEF (p < 0.05). In conclusion, our results showed that although there was a progressive decline in TD over the 4 quarters of match play, high-intensity running performance (i.e., HIR and high-intensity acceleration) was maintained throughout the match regardless of playing position.

Four Minutes of Sprint Interval Training Had No Acute Effect on Improving Alertness, Mood, and Memory of Female Primary School Children and Secondary School Adolescents: A Randomized Controlled Trial

We investigated whether a 4-min sprint interval training (SIT) protocol had an acute effect (15 min after) on improving alertness, mood, and memory recall in female students. Sixty-three children and 131 adolescents were randomly assigned to either a SIT or control (CON) group by the class Physical Education (PE) teachers. The SIT intervention was delivered twice a week for 3 weeks. SIT participants performed three, 20-s 'all-out' effort sprints interspersed with 60-s intervals of walking while CON group sat down and rested. PE lessons were arranged such that the first two sessions were to familiarise participants with the SIT protocol leading to acute assessments conducted on the third session. On that occasion, both groups rated their alertness and mood on a single-item hedonic scale and underwent an adapted memory recall test. The same assessments were administered to both groups fifteen minutes after delivery of SIT intervention. A 4-min SIT involving three, 20 s 'all-out' effort intensity sprints did not have an acute main effect on improving alertness, mood and, memory recall in female children (η_p² = 0.009) and adolescents (η_p² = 0.012). Students' exercise adherence and feedback from PE teachers are indicatives of the potential scalability of incorporating SIT into PE programmes. Different work-to-rest ratios could be used in future studies.

Efficacy of a Six-Week Dispersed Wingate-Cycle Training Protocol on Peak Aerobic Power, Leg Strength, Insulin Sensitivity, Blood Lipids and Quality of Life in Healthy Adults

The aim of this study was to evaluate the efficacy of a six-week dispersed Wingate Anaerobic test (WAnT) cycle exercise training protocol on peak aerobic power (VO_2peak), isokinetic leg strength, insulin sensitivity, lipid profile and quality of life, in healthy adults. Methods: We conducted a match-controlled cohort trial and participants were assigned to either the training (intervention, INT, N = 16) or non-training (control, CON, N = 17) group. INT performed 30-s WAnT bouts three times a day in the morning, afternoon and evening with each bout separated by ~4 h of rest, performed for 3 days a week for 6 weeks. Criterion measures of peak oxygen uptake (VO_2peak), leg strength, insulin markers such as homeostatic model assessment (HOMA) and quantitative insulin-sensitivity check index (QUICKI), blood lipids profile and health-related quality of life (HRQL) survey were assessed before and after 6 weeks in both groups. Results: Absolute VO_2peak increased by 8.3 ± 7.0% (p < 0.001) after INT vs. 0.9 ± 6.1% in CON (p = 0.41) group. Maximal voluntary contraction at 30°·s^-1 of the dominant lower-limb flexors in INT increased significantly post-training (p = 0.03). There were no changes in the INT individuals' other cardiorespiratory markers, HOMA, QUICKI, blood lipids, and HRQL measures (all p > 0.05) between pre- and post-training; but importantly, no differences were observed between INT and CON groups (all p > 0.05). Conclusions: The results indicate that 6 weeks of dispersed sprint cycle training increased cardiorespiratory fitness and dynamic leg strength but had minimal impact on insulin sensitivity, blood lipids and quality of life in the exercising individuals.

Effect of regular precooling on adaptation to training in the heat

PURPOSE

This study investigated whether regular precooling would help to maintain day-to-day training intensity and improve 20-km cycling time trial (TT) performed in the heat. Twenty males cycled for 10 day × 60 min at perceived exertion equivalent to 15 in the heat (35 °C, 50% relative humidity), preceded by no cooling (CON, n = 10) or 30-min water immersion at 22 °C (PRECOOL, n = 10).

METHODS

19 participants (n = 9 and 10 for CON and PRECOOL, respectively) completed heat stress tests (25-min at 60% [Formula: see text] and 20-km TT) before and after heat acclimation.

RESULTS

Changes in mean power output (∆MPO, P = 0.024) and heart rate (∆HR, P = 0.029) during heat acclimation were lower for CON (∆MPO - 2.6 ± 8.1%, ∆HR - 7 ± 7 bpm), compared with PRECOOL (∆MPO + 2.9 ± 6.6%, ∆HR - 1 ± 8 bpm). HR during constant-paced cycling was decreased from the pre-acclimation test in both groups (P < 0.001). Only PRECOOL demonstrated lower rectal temperature (T_re) during constant-paced cycling (P = 0.002) and lower T_re threshold for sweating (P = 0.042). However, skin perfusion and total sweat output did not change in either CON or PRECOOL (all P > 0.05). MPO (P = 0.016) and finish time (P = 0.013) for the 20-km TT were improved in PRECOOL but did not change in CON (P = 0.052 for MPO, P = 0.140 for finish time).

CONCLUSION

Precooling maintains day-to-day training intensity and does not appear to attenuate adaptation to training in the heat.

Effects of Pre-Exercise High and Low Glycaemic Meal on Intermittent Sprint and Endurance Exercise Performance

The purpose of this study is to investigate the effects of ingesting either a high glycaemic index (HGI) or low glycaemic index (LGI) carbohydrate meal (preceding a 12 h overnight fast and where the meal was ingested 45-min prior to activity) on intermittent sprint and endurance exercise performance. Ten male varsity athletes from intermittent sports (age 23.6 ± 1.7 years, VO_2max 51.9 ± 4.7 mL·kg⁻¹·min⁻¹) underwent a peak velocity (V_peak) test and familiarisation session, followed by two experimental sessions in random order. Experimental sessions involved the ingestion of either an HGI or LGI meal, followed by the completion of the modified Loughborough Intermittent Shuttle Test (mLIST). There was no significant difference between HGI or LGI meals on sprint times (p = 0.62) and distance to exhaustion (p = 0.54) in the mLIST. Exercise heart rate, blood lactate and ratings of perceived exertion were also similar between the two meal trials throughout the mLIST (all p > 0.05). Subjective ratings of hunger, fullness, satiety and satisfaction were also not significantly different between the two meals. In conclusion, consuming either an HGI or LGI meal after a prolonged 12 h fast and ingesting the meal 45 min prior to exercise did not differ in either physiological, subjective and intermittent sprint and endurance performance outcomes.

Effects of a novel exercise training protocol of Wingate-based sprint bouts dispersed over a day on selected cardiometabolic health markers in sedentary females: a pilot study

PURPOSE

Sprint interval training (SIT) provides a strong stimulus for improving cardiovascular fitness, which is among the key markers for premature mortality. Recent literature demonstrated that SIT protocols with as few as two stacked 20 s Wingate Anaerobic Test (WAnT) cycle sprints provide sufficient training stimulus for a robust increase in maximal aerobic power. However, this effect is lost when only one bout is performed. This suggests training adaptation is still dependent on the volume of SIT. Therefore, the purpose of this study was to determine the effects of three dispersed 30 s WAnT bouts, done over a day but interspersed with 4 hours of recovery time, on selected cardiometabolic health markers.

METHODS

Eighteen sedentary women, age 36±8 years, were recruited and underwent 8 weeks of supervised training using the WAnT protocol, 3 days a week. Criterion measure of cardiovascular fitness (ie, V̇O2peak), skinfolds and blood lipids such as triglyceride, low density lipoprotein (LDL) and high density lipoprotein (HDL) were measured before and after training intervention.

RESULTS

V̇O2peak improved by a mean of 14.0% after training (21.7±5.7 vs 24.7±5.7 mL/kg/min, p<0.01). No significant change was observed for body fat and lipid profile.

CONCLUSION

Performing three dispersed WAnT bouts with a 4-hour recovery period between bouts throughout a day, 3 days per week for 8 weeks provides sufficient training stimulus for a robust increase in V̇O2peak, which is comparable with other previous SIT protocols with very short recovery intervals. However, no other changes in the other cardiometabolic health markers were detected.

Effects of ingesting low glycemic index carbohydrate food for the sahur meal on subjective, metabolic and physiological responses, and endurance performance in Ramadan fasted men

PURPOSE

To investigate the effect of low glycemic index (LGI) carbohydrate meal on subjective, metabolic and physiological responses, and endurance performance in the Ramadan fasted state.

METHODS

During Ramadan, 12 Muslim men, in a randomized and crossover design, ingested for the sahur meal (i.e., last meal before commencement of the day's fast), either LGI (glycemic index = 37) or mixed (CON; ∼57) meal of equivalent macro-nutrient. At ∼12 h post-prandial, subjects completed a 60 min continuous run.

RESULTS

There were no significant differences between the two meals for ratings in perceived satiety, fullness, appetite and mood states. During steady-state exercise, there were no significant differences in metabolic and physiological measures. In the time-trial, distance ran was significantly lower in LGI versus CON meal trial, but with a corresponding lower perceived exertion in the LGI trial.

CONCLUSION

Compared to CON, ingesting LGI as the sahur meal did not provide any metabolic, physiological or performance benefits during endurance run performed 12 h post-prandial in Ramadan fasted state.

Mouth rinsing improves cycling endurance performance during Ramadan fasting in a hot humid environment

This study examined the effect of mouth rinsing during endurance cycling in a hot humid environment (32 °C and 75% relative humidity) on athletes in the Ramadan fasted state. Nine trained adolescent male cyclists completed 3 trials that consisted of a carbohydrate mouth-rinse (CMR), a placebo mouth-rinse (PMR), and a no-rinse (NOR) trial during the last 2 weeks of Ramadan. Each trial consisted of a preloading cycle at 65% peak rate of oxygen consumption for 30 min followed by a 10-km time trial (TT10 km) under hot humid condition. During the CMR and PMR trials, each cyclist rinsed his mouth with 25 mL of the solution for 5 s before expectorating the solution pre-exercise, after 5, 15, and 25 min of the preloading cycle, and 15 s prior to the start of TT10 km. Time to complete the TT10 km was significantly faster in the CMR and PMR trials compared with the NOR trial (12.9 ± 1.7 and 12.6 ± 1.7 vs. 16.8 ± 1.6 min, respectively; p < 0.017). Ratings of perceived exertion taken at the end of the TT10 km was lower in both CMR and PMR trials compared with the NOR trial, although the difference was significant only between CMR and NOR (p < 0.05). In conclusion, mouth rinsing with either carbohydrate or placebo solution provided ergogenic benefits compared with a no-rinse condition on TT10 km performance in acute Ramadan fasted subjects during endurance cycling in a heat stress environment.

Conducting an acute intense interval exercise session during the Ramadan fasting month: what is the optimal time of the day?

This study examines the effects of Ramadan fasting on performance during an intense exercise session performed at three different times of the day, i.e., 08:00, 18:00, and 21:00 h. The purpose was to determine the optimal time of the day to perform an acute high-intensity interval exercise during the Ramadan fasting month. After familiarization, nine trained athletes performed six 30-s Wingate anaerobic test (WAnT) cycle bouts followed by a time-to-exhaustion (T(exh)) cycle on six separate randomized and counterbalanced occasions. The three time-of-day nonfasting (control, CON) exercise sessions were performed before the Ramadan month, and the three corresponding time-of-day Ramadan fasting (RAM) exercise sessions were performed during the Ramadan month. Note that the 21:00 h session during Ramadan month was conducted in the nonfasted state after the breaking of the day's fast. Total work (TW) completed during the six WAnT bouts was significantly lower during RAM compared to CON for the 08:00 and 18:00 h (p < .017; effect size [d] = .55 [small] and .39 [small], respectively) sessions, but not for the 21:00 h (p = .03, d = .18 [trivial]) session. The T(exh) cycle duration was significantly shorter during RAM than CON in the 18:00 (p < .017, d = .93 [moderate]) session, but not in the 08:00 (p = .03, d = .57 [small]) and 21:00 h (p = .96, d = .02 [trivial]) sessions. In conclusion, Ramadan fasting had a small to moderate, negative impact on quality of performance during an acute high-intensity exercise session, particularly during the period of the daytime fast. The optimal time to conduct an acute high-intensity exercise session during the Ramadan fasting month is in the evening, after the breaking of the day's fast.

The implications of Ramadan fasting for human health and well-being

Islamic Ramadan is a 29-30 day fast in which food, fluids, medications, drugs and smoking are prohibited during the daylight hours which can be extended between 13 and 18 h · day(-1) depending on the geographical location and season. The majority of health-specific findings related to Ramadan fasting are mixed. The likely causes for these heterogeneous findings lie in the amount of daily time of fasting, number of subjects who smoke, take oral medications, and/or receive intravenous fluids, in the type of food and eating habits and in changes in lifestyle. During Ramadan fasting, glucose homeostasis is maintained by meals taken during night time before dawn and by liver glycogen stores. Changes in serum lipids are variable and depend on the quality and quantity of food intake, physical activity and exercise, and changes in body weight. Compliant, well-controlled type II diabetics may observe Ramadan fasting, but fasting is not recommended for type I, noncompliant, poorly controlled and pregnant diabetics. There are no adverse effects of Ramadan fasting on respiratory and cardiovascular systems, haematologic profile, endocrine, and neuropsychiatric functions.

CONCLUSIONS

Although Ramadan fasting is safe for all healthy individuals, those with various diseases should consult their physicians and follow medical and scientific recommendations.

The effects of Ramadan intermittent fasting on athletic performance: recommendations for the maintenance of physical fitness

The behavioural modifications that accompany Ramadan intermittent fasting (RIF) are usually associated with some alterations in the metabolic, physiological, and psychological responses of athletes that may affect sport performance. Muslim athletes who are required to train and/or compete during the month-long, diurnal fast must adopt coping strategies that allow them to maintain physical fitness and motivation if they are to perform at the highest level. This updated review aims to present the current state of knowledge of the effects of RIF on training and performance, focusing on key-factors that contribute to the effects of Ramadan on exercise performance: energy restriction, sleep deprivation, circadian rhythm perturbation, dehydration, and alterations in the training load. The available literature contain few studies that have examined the effects of RIF on physical performance in athletes and, to date, the results are inconclusive, so the effects of RIF on competition outcomes are not at present wholly understood. The diverse findings probably indicate individual differences in the adaptability and self-generated coping strategies of athletes during fasting and training. However, the results of the small number of well-controlled studies that have examined the effects of Ramadan on athletic performance suggest that few aspects of physical fitness are negatively affected, and where decrements are observed these are usually modest. Subjective feelings of fatigue and other mood indicators are often cited as implying additional stress on the athlete throughout Ramadan, but most studies show that these factors may not result in decreases in performance and that perceived exercise intensity is unlikely to increase to any significant degree. Current evidence from good, well-controlled research supports the conclusion that athletes who maintain their total energy and macronutrient intake, training load, body composition, and sleep length and quality are unlikely to suffer any substantial decrements in performance during Ramadan. Further research is required to determine the effect of RIF on the most challenging events or exercise protocols and on elite athletes competing in extreme environments.

Self-generated coping strategies among muslim athletes during ramadan fasting

The study explored the self-generated coping strategies employed by Muslim athletes from South East Asian region during the Ramadan fasting month. Sixty-five National elite Muslim athletes responded to an open-ended question on coping strategies employed during Ramadan fasting. Inductive content analysis identified five general dimensions from 54 meaning units which were abstracted into 14 first-order themes and 10 second order themes. The general dimension included four problem-focused coping: training modifications, dietary habits, psychological, rest and recovery, and one emotion-focused coping i.e., self- control. The coping strategies employed were diverse and dynamic in nature and no specific pattern was evident. The most frequently employed strategies were associated with training and dietary habits. Emotion focused coping was the least frequently used by the athletes. Key pointsMuslim athletes employ diverse self -generated coping strategies during Ramadan fasting which can be categorized as anticipatory coping, preventative coping and proactive coping.Frequently employed coping strategies are task focused such as training modifications and adjustments in dietary habits.

Dehydration Rates and Rehydration Efficacy of Water and Sports Drink During One Hour of Moderate Intensity Exercise in Well-trained Flatwater Kayakers

Introduction: The aim of this study is to investigate the amount of water loss and percentage dehydration experienced during 1 hour of paddling on the kayak ergometer so as to help coaches and athletes tailor a suitable and adequate rehydration regime. Also, rehydration efficacy between water and a well established, commercially available sports drink (Gatorade, Quaker Oats company, USA) was investigated in this cross-over study. Materials and Methods: Ten national flatwater kayakers were monitored in a controlled setting while paddling the kayak ergometer for 1 hour at an intensity sustainable for long distance marathon. They rehydrated themselves ad libitum with provided beverage. Post-void towel-dried body mass was measured before and after the exercise with percentage dehydration calculated. Body core temperature (tympanic temperatures), ratings of perceived exertion and thirst index were monitored every 15 minutes. The amount of fluid consumed, urine output and urine specific gravity were obtained after exercise. Results: The results [mean ± standard deviation (SD)] showed that kayakers underwent 1.10 ± 0.52% dehydration while rehydrating with water as compared to 0.72 ± 0.38% while rehydrating with Gatorade. Also, athletes on water rehydration had higher rating of perceived exertion (RPE) at the 30th and 60th minute mark of the exercise. Overall, athletes undergoing water rehydration lost significantly more body mass (0.70 ± 0.39 kg) as compared to rehydrating with Gatorade (0.46 ± 0.27). Conclusion: Although the hydration efficacy of Gatorade proved superior to that of water, the athletes’ hydration habits with either fluids did not provide adequate hydration. It is recommended that specific strategies be developed to address dehydration and rehydration issues of kayakers in Singapore. Key words: Canoe, Gatorade, Fluid replacement, Marathon

Modelling Maximal Oxygen Uptake in Athletes: Allometric Scaling Versus Ratio-Scaling in Relation to Body Mass

Introduction: Maximal oxygen uptake, VO2 & peak, among athletes is an important foundation for all training programmes to enhance competition performance. In Singapore, the VO2 & peak of athletes is apparently not widely known. There is also controversy in the modelling or scaling of maximal oxygen uptake for differences in body size – the use of ratio-scaling remains common but allometric scaling is gaining acceptance as the method of choice. Materials and Methods: One hundred fifty-eight male (age, 21.7 ± 4.9 years; body mass, 64.8 ± 8.6 kg) and 28 female (age, 21.9 ± 7.0 years; body mass, 53.0 ± 7.0 kg) athletes completed a maximal treadmill run to volitional exhaustion, to determine VO2 & peak. Results: VO2 & peak in L/min of female athletes was 67.8% that of male athletes (2.53 ± 0.29 vs. 3.73 ± 0.53 L/min), and VO2 & peak in mL/kg BM1.0/min of female athletes was 83.4% of male athletes (48.4 ± 7.2 vs. 58.0 ± 6.9 mL/kg BM1.0/min). Ratio-scaling of VO2 & peak did not create a size-free variable and was unsuitable as a scaling method. Instead, VO2 & peak, that was independent of the effect of body mass in male and female athletes, was best described using 2 separate and allometrically-derived sex-specific regression equations; these were VO2 & peak = 2.23 BM0.67 for male athletes and VO2 & peak = 2.23 BM0.24 for female athletes. Key words: Athletes, Maximal oxygen uptake, Scaling

Validity of the running repeated sprint ability test among playing positions and level of competitiveness in trained soccer players

The purpose of this study was to examine the construct validity of the running repeated sprint ability (rRSA) test to discriminate performances between: i) various playing positions (Study 1), and ii) teams of different level of competitiveness (Study 2), in trained soccer players. Study 1 comprised clubs' players participating in the top local professional league. Study 2 comprised professional and semiprofessional players from the National Under-23 and Youth squads respectively, and amateur-level players from a University team. The rRSA test protocol consisted of either 6 or 8 repetitions of 20-m all-out sprints, interspersed with a 20-s active recovery period. There were significant differences in the rRSA performance between goalkeepers and outfield-positions (p < 0.01). Forwards had significantly better rRSA performance compared to defenders and midfielders (F ratio = 4.147, p = 0.02). Performance in the rRSA was superior in teams with relatively higher competitiveness (F ratio = 3.973, p = 0.02). The rRSA is a specific physical or fitness attribute of an outfield-position player, and may be of greater importance to the forwards' position. Performance in the rRSA also seems to be associated with a higher level of competitiveness and/or adaptation to resistance training. These data support the construct validity of the rRSA test in trained soccer players.

Dehydration rates and rehydration efficacy of water and sports drink during one hour of moderate intensity exercise in well-trained flatwater kayakers

INTRODUCTION

The aim of this study is to investigate the amount of water loss and percentage dehydration experienced during 1 hour of paddling on the kayak ergometer so as to help coaches and athletes tailor a suitable and adequate rehydration regime. Also, rehydration efficacy between water and a well established, commercially available sports drink (Gatorade, Quaker Oats company, USA) was investigated in this cross-over study.

MATERIALS AND METHODS

Ten national flatwater kayakers were monitored in a controlled setting while paddling the kayak ergometer for 1 hour at an intensity sustainable for long distance marathon. They rehydrated themselves ad libitum with provided beverage. Post-void towel-dried body mass was measured before and after the exercise with percentage dehydration calculated. Body core temperature (tympanic temperatures), ratings of perceived exertion and thirst index were monitored every 15 minutes. The amount of fluid consumed, urine output and urine specific gravity were obtained after exercise.

RESULTS

The results [mean +/- standard deviation (SD)] showed that kayakers underwent 1.10 +/- 0.52% dehydration while rehydrating with water as compared to 0.72 +/- 0.38% while rehydrating with Gatorade. Also, athletes on water rehydration had higher rating of perceived exertion (RPE) at the 30th and 60th minute mark of the exercise. Overall, athletes undergoing water rehydration lost significantly more body mass (0.70 +/- 0.39 kg) as compared to rehydrating with Gatorade (0.46 +/- 0.27).

CONCLUSION

Although the hydration efficacy of Gatorade proved superior to that of water, the athletes' hydration habits with either fluids did not provide adequate hydration. It is recommended that specific strategies be developed to address dehydration and rehydration issues of kayakers in Singapore.

Modelling maximal oxygen uptake in athletes: allometric scaling versus ratio-scaling in relation to body mass

INTRODUCTION

Maximal oxygen uptake, V&O2 peak, among athletes is an important foundation for all training programmes to enhance competition performance. In Singapore, the V& O2 peak of athletes is apparently not widely known. There is also controversy in the modelling or scaling of maximal oxygen uptake for differences in body size - the use of ratio-scaling remains common but allometric scaling is gaining acceptance as the method of choice.

MATERIALS AND METHODS

One hundred fifty-eight male (age, 21.7 +/- 4.9 years; body mass, 64.8 +/- 8.6 kg) and 28 female (age, 21.9 +/- 7.0 years; body mass, 53.0 +/- 7.0 kg) athletes completed a maximal treadmill run to volitional exhaustion, to determine VO2 peak.

RESULTS

V& O2 peak in L/min of female athletes was 67.8% that of male athletes (2.53 +/- 0.29 vs. 3.73 +/- 0.53 L/min), and V& O2 peak in mL/kg BM1.0/min of female athletes was 83.4% of male athletes (48.4 +/- 7.2 vs. 58.0 +/- 6.9 mL/kg BM1.0/min). Ratio-scaling of V& O2 peak did not create a size-free variable and was unsuitable as a scaling method. Instead, V& O2 peak, that was independent of the effect of body mass in male and female athletes, was best described using 2 separate and allometrically-derived sex-specific regression equations; these were V& O2 peak = 2.23 BM0.67 for male athletes and V& O2 peak = 2.23 BM0.24 for female athletes.

Relationship between measured maximal oxygen uptake and aerobic endurance performance with running repeated sprint ability in young elite soccer players

AIM

The aim of the study was to determine the relationships between maximal oxygen uptake (VO(2max)) in a maximal treadmill run and the aerobic endurance performance in the 20-m multistage shuttle run (MST) test, with the performance indices obtained in the running repeated sprint ability (rRSA) test, in elite youth soccer players.

METHODS

Thirty-seven adolescent male outfield players performed on separate days and in random order the treadmill run test and the MST, to obtain their measured VO(2max) and aerobic endurance performance (via the number of completed shuttles in the MST), respectively. Players also completed the rRSA test of 6x20-m all-out sprints, interspersed with 20 s of active recovery.

RESULTS

There was a significant moderate correlation between measured VO(2max) (in L . min(-1) and mL . kg(-1) . min(-1)) and MST results (r=0.43 and 0.54, P<0.05, respectively). There was no significant correlation between measured VO(2max) and aerobic endurance performance with any of the performance indices in the rRSA test (all P>0.05).

CONCLUSION

The moderate association between the measured VO(2max) and MST suggests that both tests were plausibly measuring different aspects of a player's aerobic fitness. The lack of association between measured VO(2max) and aerobic endurance performance in the MST with performance in the rRSA suggests that aerobic fitness per se is poorly associated with performance in the rRSA in elite youth soccer players.

Measuring and predicting maximal aerobic power in international-level intermittent sport athletes

AIM

The purpose of this study was to measure actual VO2max during the multi-stage fitness test (MSFT) and to compare this with predicted values obtained using previously established, commonly used methods. We also wanted to determine a new and more accurate regression equation for the prediction of VO2max in intermittent sport athletes.

METHODS

Twenty-six, elite, male, intermittent sport athletes performed the MSFT with oxygen uptake (VO2) and heart rate (HR) measured throughout. Paired t-tests were used to compare measured VO2max with predicted VO2max. Linear regression was used to determine the equation for the prediction of VO2max from the total number of shuttles completed.

RESULTS

There were no differences between the two methods of predicting VO2max, however, both predicted values (53.6+/-3.9 and 51.3+/-4 mL x kg(-1) x min(-1)) were significantly lower (9.3% and 13.2%, respectively) than measured VO2max (59.1+/-6.6 mL x kg(-1) x min(-1), P < 0.001). Correlations between measured and predicted VO2max were similar for both prediction methods (r = 0.61, P = 0.013 and r = 0.68 and P = 0.004). We present a new prediction equation [Y (VO2max, mL x kg(-1) x min(-1)) = 0.38 x total number of shuttles completed +25.98] (where R = 0.69; R2 = 0.48; SEE = 4.9 mL x kg(-1) x min(-1); SEE% = 8.3) which provides a more valid method of predicting actual max in intermittent sport athletes.

CONCLUSIONS

A new regression equation to predict VO2max in intermittent sport athletes has been established. Whilst some error in predicting VO2max still exists, the new equation will provide coaches and sport-scientists with a more suitable equation with which to predict VO2max in intermittent sport athletes.

Indicators of maximal hiking performance in Laser sailors

Laser class sailors have to hike out, i.e. hook their feet under the toe straps near the centreline of the boat and hold their upper bodies over the edge of the boat, to counteract the heeling forces generated by the sails. To identify the parameters that are associated with maximal hiking performance, this cross-sectional observational study measures various knee extensor and hip flexor muscle performance characteristics in 55 Laser sailors and correlates each with the area-under-the-curve hiking moment over 3 min of hiking on a hiking dynamometer (HM180). Our results showed that higher body mass and HM180 were significantly associated with better race scores (Spearman's rho = - 0.69 and - 0.62, respectively, both P < 0.01) in male sailors who participated in the National Inter-School Laser competition. Body mass (Pearson's correlation coefficient, r > or = 0.95, P < 0.01 in both males and females), maximum voluntary isometric strength of the quadriceps (r > or = 0.80, P < 0.01 in both males and females), and 3-RM knee extension strength (r > or = 0.80, P < 0.01 in both males and females) were associated with a higher HM180. The correlations between height, abdominal muscle endurance (crunches), explosive lower body strength (vertical jumps), cycling time-to-exhaustion, quadriceps strength endurance, or isometric quadriceps endurance with incremental loads (bucket test), and HM180 were weaker (r < 0.60). HM180 may be a useful performance indicator for Laser racing. Since strength measures correlated well with HM180, greater emphasis should be placed on developing maximum strength in the quadriceps to improve maximal hiking performance.

Measured maximal oxygen uptake in a multi-stage shuttle test and treadmill-run test in trained athletes

AIM

The aims of the study were: i) to compare the measured maximal oxygen uptake (MVO2max) during the 20 m multi-stage shuttle test (MST) with MVO2max during an incremental treadmill-run test (TRT), and ii) to establish the reliability of MVO2max during MST, in trained athletes.

METHODS

EXPERIMENTAL DESIGN

8 well-trained endurance-athletes (END) and 8 athletes involved in team games (GAM) performed the MST twice (i.e. MST1 and MST2) and the TRT once, in 3 separate sessions.

MEASURES

MVO2maxx attained in the MST and TRT was measured using a portable respiratory analyser (model K4 RQ, Cosmed).

RESULTS

MVO2max attained in the MST and TRT were significantly different for the END athletes (4.1+/-0.28 vs 4.45+/-0.31 Lxmin-1, P<0.05) but not for GAM athletes (4.01+/-0.51 vs 4.1+/-0.59 Lxmin-1, P>0.05). The 95% limits of agreement for MVO2max in the MST in Lxmin-1 were -0.67 to 0.27. MVO2max in MST1 and MST2 were not significantly different for END athletes (4.18+/-0.39 vs 4.1+/-0.28 Lxmin-1, P>0.05) and GAM athletes (4.01+/-0.55 vs 4.01+/-0.51 Lxmin-1, P>0.05). Reliability indicators for MVO2max in Lxmin-1 for MST test-retest were: typical error (TE)=0.14, coefficient of variation (CV)=3.5 and intra-class correlation (ICC)=0.90.

CONCLUSION

MVO2max in the MST was lower than that measured in the TRT for the END athletes but not for the GAM athletes. Sport-specificity was an important consideration, especially when testing END athletes for VO2max. MVO2max in the MST showed acceptable levels of reproducibility.

Reproducibility of outdoor flat and uphill cycling time trials and their performance correlates with peak power output in moderately trained cyclists

The aims of the present study were firstly to examine the reproducibility of outdoor flat and uphill cycling time trials (TT), and secondly to assess the relationship between peak power output (Wpeak) obtained in the laboratory and outdoor cycling performance in moderately trained cyclists. Eight competitive male cyclists first performed a progressive cycle ergometer test in the laboratory to determine Wpeak (W). Thereafter, they performed three 36 km TT (TT36) on a flat course on separate days and at the same time of the day. On a different day, they also performed three 1.4 km uphill TT (TT1.4) in a single day. The coefficient of variation (CV) values across three TT36 and TT1.4 ranged from 1.1 - 1.4% and 2.6 - 2.9%, for performance time (min) and mean power (W), respectively. The correlation between absolute Wpeak (W) obtained in the laboratory and mean power during TT36 and TT1.4 was 0.90 (p < 0.01) and 0.98 (p < 0.01), respectively. Absolute Wpeak (W) correlated significantly with performance time in TT36 (r = -0.72, p < 0.05) but not in TT1.4 (r = -0.52, p > 0.05). The correlation between relative Wpeak (W·kg(-1)) and performance time in TT36 and TT1.4 was r = -0.65 (p > 0.05) and r = -0.91 (p < 0.01), respectively. In conclusion, under stable environmental conditions, performance time and mean power are highly reproducible in moderately trained cyclists during outdoor cycling TT. Laboratory determined absolute Wpeak (W) may predict cycling performance on a flat course but relative Wpeak (W·kg(-1)) is a better predictor of performance during uphill cycling. Key PointsUnder stable environmental conditions, performance time and mean power are highly reproducible in moderately trained cyclists during outdoor flat and uphill cycling time trials.Laboratory determined peak power output (Wpeak) (W) may predict cycling performance on a flat course.Laboratory determined relative Wpeak (W·kg(-1)) is a better predictor of performance during uphill cycling.

A pilot study comparing two field tests with the treadmill run test in soccer players

This study compares the performances obtained during soccer-specific field tests of the 20 m multistage shuttle run test (MST) and the Yo-Yo intermittent endurance test (YIET), with the measured maximal oxygen uptake (VO2max) obtained in both field tests as well as that obtained in the traditional test of running to exhaustion on a treadmill (TRT), in young trained soccer players. Twenty-one National-level youth players performed, in random order, the MST and YIET to determine the relationship between the two field tests. From these, eight randomly chosen players performed their field tests as well as a TRT, equipped with an ambulatory gas exchange measurement device. Pearson correlation coefficient analysis showed that the players' performance (i.e. distance covered) in the MST and YIET was correlated (r = 0.65, p < 0.01). Players' performance in the YIET was not significantly correlated with the measured VO2max obtained in the same YIET nor with the measured VO2max obtained in the MST and in the TRT (all p > 0.05). In contrast, significant correlations were observed between the players' performance in the MST with the measured VO2max obtained in the same MST and in the YIET (both p < 0.05); and attained almost statistical significance with the measured VO2max in the TRT (p = 0.06). The lack of association between distances covered in the YIET with all the measured VO2max values suggest that measured VO2max per se may not be suitable to characterize soccer players' intermittent endurance performance. In comparison with the MST, the YIET may be a more favourable field-based assessment of soccer player's endurance performance. Key PointsBoth the Yo-Yo intermittent endurance test and 20m multistage shuttle run test are valid measures of aerobic exertion in soccer playersMeasured VO2max per se may not be suitable to characterize soccer players' intermittent endurance performance.In comparison with the MST, the YIET may be a more favourable field-based assessment of soccer player's endurance performance.

Physiological Responses to Single versus Double Stepping Pattern of Ascending the Stairs

The aim of this study was to compare the physiological responses and energy cost between two ascending patterns, the single-step (SS) and the double-step (DS), in climbing a public staircase. In the SS pattern, a person climbs one step at a time whilst in the double-step (DS) pattern, the individual traverses two steps in a single stride. Advocates of each stepping pattern claimed that their type of ascent is physically more taxing and expends more calories. Thirty subjects (10 males and 20 females) climbed a typical 11-storey flat (each step height of 0.15 m, a total of 180 steps and a vertical displacement of 27.0 m). The subjects climbed using either the SS pattern at a tempo of 100 steps x min(-1) or the DS pattern at 50 steps x min(-1). The prescribed stepping frequencies ensured that an equal amount of total work was performed between the SS and DS patterns. The climbing patterns were performed in random order. Physiological measures during the last 30 s of the climbs were used in the comparative analysis. The results showed that ventilation, oxygen uptake and heart rate values were significantly higher (all p < 0.01) in the SS as compared to the DS pattern. However, the caloric expenditure during the SS pattern was calculated to be only marginally higher than the DS pattern. In conclusion, ascending with the SS pattern led to significantly higher physiological responses compared to the DS pattern. The higher calorie expended with the SS compared to the DS pattern was deemed to be of little practical significance.

Physiological responses during matches and profile of elite pencak silat exponents

This is a descriptive, cross-sectional study describing the physiological responses during competitive matches and profile of elite exponents of an emerging martial art sport, pencak silat. Thirty exponents (21 males and 9 females) were involved in the study. Match responses (i.e. heart rate (HR) throughout match and capillary blood lactate concentration, [La], at pre-match and at the end of every round) were obtained during actual competitive duels. Elite silat exponents' physiological attributes were assessed via anthropometry, vertical jump, isometric grip strength, maximal oxygen uptake, and the Wingate 30 s anaerobic test of the upper and lower body, in the laboratory. The match response data showed that silat competitors' mean HR was > 84% of estimated HR maximum and levels of [La] ranged from 6.7 - 18.7 mMol(-1) during matches. This suggests that competitive silat matches are characterised by high aerobic and anaerobic responses. In comparison to elite taekwondo and judo athletes' physiological characteristics, elite silat exponents have lower aerobic fitness and grip strength, but greater explosive leg power (vertical jump). Generally, they also possessed a similar anaerobic capability in the lower but markedly inferior anaerobic capability in the upper body.

Physiological characteristics of Singapore national water polo team players

BACKGROUND

The purpose of this study is to describe the physiological characteristics of members of the Singapore national water polo team.

METHODS

EXPERIMENTAL DESIGN

a descriptive study on the physiological characteristics of members of a winning water polo team.

SETTING

the study was conducted at the Sports Medicine and Research Centre.

PARTICIPANTS

13 male players (22.5+/-7.2 yrs; 178.5+/-3.9 cm and 71.0+/-8.4 kg).

MEASURES

players completed body fat measurements, a submaximal cycling test to determine aerobic fitness and all-out maximal efforts (of arm-cranking and cycling) for 10 and 30 sec duration to determine anaerobic peak power, alactic and lactic acid work capacity for the upper and lower body.

RESULTS

The physical measurements were compared with data of national players of various countries. The exercise test results were compared with available published data.

CONCLUSIONS

Compared with elite water polo players from other countries, the Singapore water polo players are smaller in stature with a lower body mass. Relative to the limited published data, they are shown to possess a high level of aerobic fitness and anaerobic power and capacity for short-term work.

Heart rate, oxygen uptake, and energy cost of ascending and descending the stairs

PURPOSE

This study describes the heart rate and oxygen uptake responses during, and the intensity and caloric cost of, ascending and descending a public-access staircase.

METHODS

Subjects were initially assessed for their maximum oxygen uptake and heart rate on a treadmill in the laboratory. For field measurements, subjects ascended (N = 103) and descended (N = 49) 11 stories of 180 steps, each step of 15 cm in height, for a total vertical displacement of 27.0 m.

RESULTS

The mean oxygen uptake and heart rate during the last 30 s of ascending were 33.5 +/- 4.8 mL.kg(-1).min(-1) and 159 +/- 15 beats.min(-1), respectively. During the descent, oxygen uptake and heart rate during the last 30 s of the climb were 17.0 +/- 3.8 mL.kg(-1).min(-1) and 107 +/- 18 beats.min(-1), respectively. The estimated gross energy expended during ascending and descending were 19.7 and 9.0 kcal, or equivalent to an intensity of 9.6 and 4.9 metabolic equivalents (METs), respectively (or 10.2 and 5.2 kcal.min(-1), respectively). The caloric cost of stepping up and down a step was calculated to be 0.11 and 0.05 kcal, respectively.

CONCLUSION

Stair-climbing exercise using a local public-access staircase met the minimum requirements for cardiorespiratory benefits and can therefore be considered a viable exercise for most people and suitable for promotion of physical activity.

Aerobic demands of the dance simulation game

The purpose of this study was to assess the intensity and energy cost of dance simulation in relation to the American College of Sports Medicine (ACSM) recommendations on the quantity and quality of exercise for developing and maintaining cardiorespiratory fitness, and to assess its safety. Forty subjects (21 males and 19 females, age 17.5 +/- 0.7 years) had their heart rate (HR) and oxygen consumption (.VO(2)) measured during maximal treadmill exercise and during a dance simulation game at a self-selected level of difficulty. They were monitored for injuries during and after the study. The results showed a mean HR of 137 beats x min(-1) (139 beats x min(-1) for males and 136 beats x min(-1) for females) and a mean .VO(2) of 24.6 ml x kg(-1) x min(-1) (25.3 ml x kg(-1) x min(-1) for males and 23.8 ml x kg(-1) x min(-1) for females) during the dance simulation game test, with an estimated energy expenditure of 480 W (550 W for males and 410 W for females). The dance intensity only just meets the minimum ACSM guidelines, so dancer-players will need to play for extended periods to improve or maintain cardiorespiratory fitness or to lose weight. No injuries occurred during 201 hours of dance time.

Grip strength measurement in competitive ten-pin bowlers

BACKGROUND

In an attempt to find a more specific grip strength test for bowlers, the conventional grip strength test was modified such that only the fingers used in holding the ball are tested. The objective of this study was to assess the test-retest reliability of this modified bowling grip strength test, to assess the agreement between the bowling and the conventional grip strength tests, and to examine the correlation between the modified test and bowling performance in competitive bowlers. METHODS.

EXPERIMENTAL DESIGN

This research was conducted in two parts, each with a different study sample. Study I was a cross-sectional study to assess the correlation between the bowling grip strength and the bowling score. Study II was a comparative study to obtain the test-retest reliability for both the bowling and conventional grip strength tests, and to assess the agreement between the two tests.

SETTING AND SUBJECTS

for study I, the subjects were 39 members (26 males and 13 females) of the Singapore National Ten-Pin Bowling Training Squad. Bowling grip strength was measured within one month prior to the selection trials for the national squad, the results of which were used as a measure of bowling performance. For study II, the subjects were 21 members (12 males and 9 females) of the Singapore National Ten-Pin Bowling Squad that was formed after the selection trials.

INTERVENTIONS

none.

MEASURES

Bowling grip strength, conventional grip strength, and bowling score.

RESULTS

The test-retest reliability of the bowling grip strength measurement (r = 0.91, p < 0.01) was comparable to that of the conventional five-finger grip (r = 0.93, p < 0.01). The single measure intraclass correlation coefficient between the bowling and conventional grip strength tests was 0.77; the 95% confidence interval was 0.51 and 0.90. However, the correlation coefficient between the bowling grip strength test and bowling score (r = 0.27) was not significant.

CONCLUSIONS

The bowling grip strength test has a high test-retest reliability, and a moderate agreement with the conventional grip strength test. However, despite using only the bowling fingers, the test was unable to predict bowling performance in elite bowlers.

A stair-climb test of cardiorespiratory fitness for Singapore

OBJECTIVE

The purpose of this study was to develop a stair-climb test of cardiorespiratory fitness for adult Singaporeans, particularly those staying in Singapore Housing and Development Board (HDB) flats.

METHOD

103 subjects [56 males, of mean (SD) age 44.8 (13.9) years and Body Mass Index, or BMI, 23.3 (3.2); and 47 females, of age 43.2 (12.9) years and BMI 21.9 (2.8)] were first assessed for their cardiorespiratory fitness, measured using maximal oxygen uptake (or VO2max) on a treadmill, before undergoing a stair-climb test up to the 12th storey (11 floors) of a typical HDB flat (180 steps, vertical height 27.0 metres).

RESULTS

The mean (SD) time taken for the climb (CT) and heart rate at the end of the climb (HRend) averaged 111.3 (16) seconds and 154.4 (13.4) beats.min-1 respectively for males, and 121.0 (18.1) seconds and 164.6 (15.7) beats.min-1 respectively for females. Regression equations were developed to predict VO2max from age (years), BMI, CT (seconds), HRend (beats.min-1): For males: VO2max (ml.kg-1.min-1) = 133 - 0.273 (Age) - 0.672 (BMI) - 0.236 (CT) - 0.232 (HRend). For females: VO2max (ml.kg-1.min-1) = 66.69 - 0.135 (Age) - 0.249 (BMI) - 0.128 (CT) - 0.021 (HRend). Validation of the regression equations conducted on a different sample consisting of 18 subjects (11 male and 7 female) showed significant correlations between the predicted and directly measured VO2max (males, r = 0.81 and females, r = 0.90; p < 0.01). There were no significant differences between the means of predicted and directly measured VO2max.

CONCLUSION

A stair-climb test using HDB stairs was developed which was able to estimate cardiorespiratory fitness with reasonable accuracy.

The relationship between maximal oxygen uptake and repeated sprint performance indices in field hockey and soccer players

BACKGROUND

The purpose of this study was to examine the relationship between maximal oxygen uptake and repeated sprint performance in field hockey and soccer players.

METHODS

EXPERIMENTAL DESIGN

a descriptive study on the aerobic-anaerobic performance of intermittent team game players.

SETTING

the study was conducted at the Sports Medicine and Research Centre.

PARTICIPANTS

forty male national team game players (22.6+/-4.2 years; 1.73+/-0.07 m and 63.7+/-6.2 kg) were involved in the study.

MEASURES

all subjects completed a treadmill run test to exhaustion to determine maximal oxygen uptake and 8x40 m sprints either on the field or running track to determine repeated sprint ability performance.

RESULTS

Body mass-normalised maximal oxygen uptake of 58.0+/-4.9 ml x kg(-1) x min(-1) of the group is comparable to values reported in the literature for team game players. No significant correlations were established between the fastest 40 m sprint time and maximal oxygen uptake (r=-0.21 and -0.08, p>0.05). Moderate correlations were established between maximal oxygen uptake and total time for the eight sprints (r=-0.346 and -0.323; p<0.05).

CONCLUSIONS

Maximal oxygen uptake was not correlated with the fastest 40 m sprint time but was moderately correlated with total sprint time. Since the shared variance between maximal oxygen uptake and total sprint time was only 12%, improving aerobic fitness further will only be expected to contribute marginally to improving repeated sprint performance of the team game players. It remains possible that a high level of aerobic fitness enhances other aspects of match play in games like soccer and hockey.

Correlations between physiological parameters and performance in elite ten-pin bowlers

The increasing acceptance of ten-pin bowling as a sport, as well as the keen competition amongst bowlers, necessitates the identification of performance indicators to aid training. The aim of this cross-sectional study was to determine if age, height, weight, aerobic power index, bowling grip strength, 10-RM leg press performance, and the sit-and-reach distance correlated with bowling performance in 42 elite bowlers (26 males and 16 females). At the same time, the physiological profiles of bowlers classified as heavy ball strokers, heavy ball crankers, and light ball spinners were compared. The results showed that for the male bowlers, none of the parameters correlated with performance, while for the female bowlers, the only parameter that correlated with performance was the aerobic power index. Bowlers using the three different releases had similar anthropometric and physiological profiles. The implications from this study are that bowlers of diverse age and build can be equally competitive in the sport; that aerobic capacity (as reflected by the aerobic power index) may, to a certain extent, contribute to bowling performance; and that strength and flexibility measures do not seem to be useful performance indicators amongst elite bowlers.