Journal Articles

The purpose of this project was to utilise global-positioning system (GPS) technology to understand the physical demands of youth international field hockey. Methods: Sixteen male field hockey players (age 17.1 ± 0.6 y, stature 165 ± 11 cm, body mass 63.3 ± 6.6 kg, estimated VO2max, 52.6 ± 5.3 ml/kg/min) were investigated while competing in 6 matches at the 2011 Boy’s Under-18 Asia Cup. Each player wore a GPS unit during competition to track his movement. These movements were classified as either low-speed activity (<4.17 m/s) or high-speed activity (>4.17 m/s). Positional differences were analysed using magnitude-based Cohen’s effect size with modified qualitative descriptors. Results: Forwards covered the most distance per minute across total distance, low-speed activity and high-speed activity in the 6 youth international field hockey matches. For high-speed activity there was a “Large” difference between the Defenders and Midfielders and a “Very Large” difference between the Defenders and Forwards. Conclusion: In youth international field hockey, Forwards cover the greatest amount of distance and carry out the most high-speed activity, while Defenders perform the least amount of high-speed activity. This suggests that these playing positions are sufficiently different to warrant specialised positional training.

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.

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, VO2max 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, ƞ2p = .45 and P < .001, ƞ2 =0.72), maximal aerobic speed (MAS) (P = .006, ƞ2p = .39), CMJ height (P < .001, ƞ2p = .55) and IMTP relative peak force (P = .001, ƞ2p = .50) in favor of PT and IST. Significant main effect for time was observed for 2.4kmTT (P < .001, ƞ2p = .72), RE (P = .048, ƞ2p = .17), VO2max (P = .047, ƞ2p = .18), MAS (P < .001, ƞ2p = .63), CMJ height (P < .001, ƞ2p = .51) and IMTP relative peak force (P < .001, ƞ2p = .58). Conclusion: In conclusion, both PT and IST were similarly effective at enhancing running endurance performance. However, IST resulted in greater improvement to RE.

Ramadan fasting increases subjective feelings of fatigue and reduces self- motivation during exercise. Exercising in the Ramadan fasted state leads to a quality of training that is lower than normal due to a reduction in exercise intensity and/or physical efforts. This field investigation examined the impact of Ramadan fasting on perceived exercise intensity during high intensity training sessions and its impact on maximal aerobic performance, in elite-level youth soccer players. The National Under-18 squad was organized into a fasting (FAS) and a non-fasting (control, CON) groups. During the Ramadan month, in addition to the normal soccer-specific training, both FAS and CON underwent six specific conditioning sessions consisting of high-intensity aerobic and anaerobic interval running. There were no significant differences between groups' post-exercise ratings of perceived exertion in all sessions. There were no significant differences between groups for Beep test performances at pre- and post-Ramadan. There was no adverse effect of fasting on perceived exercise intensity in Ramadan fasted players, and also no impact on their maximal aerobic performance post-Ramadan.

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.

The primary aim of the review is to present a balanced narrative of adult stair use. Healthy young and older adults can expect to reap multiple anthropometric, neuromuscular, physiological, and metabolic health benefits following adherence and accomplishment of stair use that is sustained over 2 to 12 weeks, at least 3 times a week, at a moderateto-vigorous intensity, either within exercise designs of continuous and sustained exercise, or within a timesaving, low volume, and high-intensity interval training set up. There are inherent risks of falls in stair use and participants should adhere to safety tips when navigating stairs in daily life as a form of commute or as intentional exercise. Additional steps for safety and inclusiveness to adult stair use exercise include customizing stair use to suit individual health, fitness, and the exercise context including those with special needs and medical conditions by working with medical practitioners.

Maximal oxygen uptake, V02 peak, among athletes is an important foundation for all training programmes to enhance competition performance. In Singapore, the \ro2 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 determineyo2 peak.~: \ro2 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 \ro2 peak in mL/kg BMt.0/min of female athletes was 83.4% of male athletes (48.4 ± 7.2 vs. 58.0 ± 6.9 mL/kg BMt.0/min). Ratioscaling of \ro2 peak did not create a size-free variable and was unsuitable as a scaling method. Instead, \rQ2 peak, that was independent of the effect of body mass in male and female athletes, was best described using2 separate and allometrically-derived sex-specific regression equations; these were \rQ2 peak = 2.23 BM0.670 or male athletes and \ro2 peak = 2.23 BM0.24 for female athletes.

The attainment of an oxygen uptake (VO2) plateau during maximal incremental exercise is often considered as a criterion for the elicitation of a maximal effort. However there is growing evidence that a (VO2) plateau does not occur in all adult subjects despite exercise to volitional exhaustion. One school of thought is that aerobically trained subjects or subjects with a higher maximal VO2 were more likely to demonstrate the VO2 plateau phenomenon than subjects with lower maximal VO2. The study investigated the frequency of occurrence of the VO2 plateau, defined as an increase in VO2 of less than 1.5 ml/kg/min in trained Asian male (n=158, age=21.7±4.9y; body mass=64.8±8.6kg) and female (n=28, age=21.9±7.0y; body mass=53.0±7.0kg) athletes during a maximal treadmill run to volitional exhaustion, to determine maximal VO2. The VO2 plateau phenomenon was only detected in 53% of the male athletes and 64% of the female athletes, despite the lower ratio-scaled peak VO2 values (48.4±7.2 vs. 58.0±6.9 ml/kg BM/min; p<0.05) of the female athletes compared to the male athletes. These data refuted the assertions that athletes with higher aerobic fitness were more likely to show a VO2 plateau, and that the lack of a VO2 plateau was due to poor motivation on the part of untrained adults to give a maximal effort.