Balasekaran, Govindasamy

The study examined the motion sensor outputs of Singaporean children and adolescents of both sexes to walking and running on a motorized treadmill (Quinton Series 90) under controlled laboratory conditions. 58 youths of normal body mass (N=58, age: 13.2±3.0 y; height: 1.53±0.02 m; body mass: 45.5±14.2 kg; BMI: 18.8± 3.0 kg/m2; Tanner rating: 2.5±1.3) were recruited for the study. Accelerometer (ActiGraph GT 1 M) activity (ActiCounts in counts/min) and step rate (ActiSteps in steps/min) and pedometer (Omron HJ 005-E) step rate (PedoSteps in steps/min), oxygen uptake (in ml/kg/min) and heart rate (in bpm) were obtained from 5-minutes stages of 0 % gradient of treadmill walking at 4 km/hr and running at 6 km/hr and 8 km/hr. Walking at 4 km/hr was estimated at 4.0-6.0 METs, whilst running at 6 km/hr and 8 km/hr was estimated at 6.3-8.6 and 10.0-11.4 METs, respectively. Motion sensor outputs increased significantly with treadmill speeds (76-101 % for ActiCounts; 22-24 % for ActiSteps and18-25 % for PedoSteps, all p<0.01) as did oxygen uptake (48-55 %) and heart rate (27-28 %) but there was no sex difference in activity or step rate or physiological responses (p>0.01). No meaningful relationships were obtained between accelerometer activity rate and oxygen uptake or heart rate. There was acceptable agreement between accelerometer and pedometer step rate for the walking and running on the treadmill but the difference between accelerometer and pedometer step rate was smallest at a treadmill running speed of 6 km/hr. These results show that accelerometer and pedometer step rates are useful and suitable measurements of physical activity involving walking and running among Singaporean children and adolescents of normal body mass. Further investigations are necessary to fully exploit the use of accelerometer data in physical activity research among young people.

Classroom-based physical activity (PA) interventions have received considerable attention due to improvements seen in academic achievement, classroom behaviors, and attitude toward PA. The purpose of this study was to evaluate the effectiveness of the Brain Breaks® Physical Activity Solutions in changing children’s attitudes toward PA. Students (N = 3036) aged 8–11 years from schools in Croatia, Lithuania, Macedonia, Poland, Romania, Serbia, South Africa, and Turkey were randomly assigned to either a control or an experimental group. The experimental group received Brain Breaks® videos during classroom sessions throughout the four months of intervention. Student attitudes toward PA were measured using the Attitudes toward Physical Activity Scale (APAS) before and after the intervention. Repeated measures ANOVA indicated a time interaction effect for all APAS variables except fitness. Time-by-group interaction effects with different effect sizes were found for most APAS variables, with the greatest gain effect noted in the experimental group for self-efficacy, followed by learning from the videos concerning PA benefits, exercise importance, and enjoyment from engaging in PA. This study provides evidence supporting Brain Breaks® in terms of learning experience, attitudes towards PA, and personal motivation. Using exercise videos is recommended as an interactive, technology-based PA solution that can be easily integrated into the school setting.

During the novel coronavirus (COVID-19) pandemic, physical activity (PA) behaviors were altered worldwide due to public health measures such as “lockdown.” This study described PA among adults residing in 11 countries during COVID-19 lockdown and examined factors associated with PA engagement. We conducted a cross-sectional anonymous survey among adults (≥18 years old) in 11 countries (Brazil, Bulgaria, China, India, Ireland, Malaysia, North Macedonia, Singapore, Spain, Turkey, United States). Of 11,775 participants, 63.7% were female and 52.8% were 18–34 years old. More than 40% of participants were insufficiently active (43.9%) and reported a decrease in their PA during lockdown (44.8%). Statistically significant differences were observed in (1) proportions of participants being insufficiently active, (2) level of PA, and (3) decrease in PA across the 11 countries. More stringent governmental policy responses were associated with greater likelihood of being insufficiently active during lockdown (adjusted odds ratio = 1.22, 95% confidence interval = 1.03, 1.45). Higher depression or anxiety scores were associated with greater likelihood of decreased level of PA during lockdown.We found substantial reductions in PA levels during COVID-19 lockdown across countries. Country-specific PA promotion interventions are needed during this and similar global emergencies.

Prediction of performance is an important parameter in exercise, especially in sports. There are several ways to predict performance, however many are fraught with difficulties such as error of prediction being too large or the lack of reliability and validity [1]. The recently published Maximal Aerobic Speed (MAS) validation and the Running Energy Reserve Index (RERI) had lower errors in predicting world class, elite, sub elite and collegiate performances [1,2]. The use of MAS and Maximal Anaerobic Speed to predict performance has been used previously by Bundle et al [3]. However, the errors in acquiring MAS may have caused prediction errors due to the existence of large anaerobic energy. The concept of removing anaerobic energy from an individual to accurately acquire a true MAS is a novel idea to predict performances with lower errors in all sports, especially sports which involve running [1]. RERI is an index which may be useful for most practitioners. Using an example of a world class runner, Sebastian Coe’s 400m and 1609m in 1981, the prediction accuracy was 1.8% and 1.0% for his 800m and 1000m respectively. This was comparable to Bundle’s two trials equation (1000m = 1.5% and 800m = 2.0%). However, the Bundle’s equation is limited to only predicting performances up to 240 seconds. The results from the MAS and RERI studies suggest that RERI can accurately predict running performances of world class runners when utilizing any two running performances within 5000m distance performance. Kinesiologists can also use the RERI model as an accurate and non-invasive alternative to time consuming methods of determining anaerobic and aerobic running performances [4,5] across various modalities of sports [6]. Training can also be compartmentalized into aerobic and anaerobic energy systems with accuracy, thus optimizing and increasing the potential of individuals with customization specialized training. The concept of talent identification using RERI in terms of identifying superiority in one energy system versus another, may be used in streamlining the potential of an individual to his strengths. For example, RERI can be used to identify a striker in soccer who is superior in anaerobic energy system versus a midfielder who may need more aerobic energy system. Moreover, RERI can be used to select a short distance runner versus a long-distance runner. Such identification may help exercise practitioners to select and train accordingly with the energy systems. Hence, it is essential knowledge and information that Kinesiologists can use to develop training programs to suit athletes of various standards (youth, collegiate, sub-elite, elite, and world class) and predict training performance for them. Such specialized science-based training may improve and enhance overall sporting performances all over the world.

The purpose of this study was to investigate the effects of classroom-based Brain Breaks® Physical Activity Solution in Southeast Asia Singaporean primary school students and their attitude towards physical activity (PA) over a ten-week intervention. A total of 113 participants (8-11 years old) were randomly assigned to either an experimental (EG) or a control group (CG), with six classes to each group; the Brain Breaks® group (EG: six classes) and the Control group (CG: six classes). All EG members participated in a Brain Breaks® video intervention (three-five min) during academic classes and the CG continued their lessons as per normal. The student's attitudes towards PA in both research conditions were evaluated using the self-reported Attitudes toward Physical Activity Scale (APAS), applied before and after intervention. The effects of the intervention on APAS scores were analysed using a mixed model analysis of variance with Time as within-subject and Group as between-subject factors. The analysis revealed evidence in support of the positive effect of classroom video interventions such as Brain Breaks® on student's attitudes toward benefits, importance, learning, self-efficacy, fun, fitness, and trying to do their personal best in PA. The Brain Breaks® intervention provided a positive significant impact on students in Singapore. This study also revealed that interactive technology tools implemented into the school curriculum benefit students in terms of health and education.

The purpose of the study was to compare the change in dynamic and isometric force-time characteristics after plyometric (PLYO) or isometric strength training (ISO). Twenty-two endurance runners (age = 37 ± 6 years,stature = 1.71 ± 0.05 m, body mass = 62.7 ± 8.6 kg, weekly mileage = 47.3 ± 10.8 km) performed a countermovement jump (CMJ) and isometric mid-thigh pull (IMTP) test during pre- and post-tests. They were then randomly assigned to either PLYO or ISO group and completed 12 sessions of intervention over six weeks. The PLYO included drop jump, single leg bounding and split jump, and the ISO included IMTP and isometric ankle plantar flexion. Significant and large time x group interactions were observed for CMJ countermovement depth (P = 0.037, ƞ²p = 0.21) and IMTP and relative peak force (PF) (P = 0.030, ƞ²p = 0.22). Significant and large main effects for time were observed in CMJ height, peak power, propulsive phase duration, countermovement depth, reactive strength index modified, IMTP PF and relative PF (P < 0.05, 0.20 ≤ ƞ²p ≤ 0.65). Effect for time showed small improvement in CMJ height for both PLYO (P < 0.001, d = 0.48) and ISO (P = 0.009, d = 0.47), small improvement in CMJ PP in PLYO (P = 0.020, d = 0.21), large increase in countermovement depth (P = 0.004, d = 1.02) and IMTP relative PF (P < 0.001, d = 0.87), and moderate increase in propulsive phase duration (P = 0.038, d = 0.65) and IMTP PF (P < 0.001, d = 0.55) in ISO. There were large differences between groups for percentage change in countermovement depth (P = 0.003, d = 0.96) and IMTP relative PF (P = 0.047, d = 0.90). In conclusion, both PLYO and ISO improved CMJ jump height via different mechanisms, while only ISO resulted in improved IMTP PF and relative PF.

Performing isometric strength training (IST) can enhance various sports performance. This study compared the effects of including IST on sprint kayaking performance as compared to traditional strength training. Twenty sprint kayaking athletes (age 22 ± 4 year, stature 1.71 ± 0.09 m, body mass 72.0 ± 11.4 kg) performed a 200-m kayak ergometer time trial (200mTT), isometric squat (IsoSqT), isometric bench press (IsoPress) and isometric prone bench pull (IsoPull) during the pre- and post-tests. Athletes were randomly assigned to either traditional strength training (TRAD) or IST group. Both groups performed a similar strength training program twice a week for six weeks. However, half the volume for squat, bench press and prone bench pull were replaced by IsoSqT, IsoPress and IsoPull, respectively, for the IST group. IsoSqT was performed at 90° knee angle, while IsoPress and IsoPull were performed at 90° and 120° elbow angles, respectively. Each isometric contraction was performed with maximum intensity and sustained for three seconds. A significant main time effect was observed for 200mTT (p < 0.001, ƞ²_p = 0.68) and all isometric strength measures (p = 0.001–0.032, ƞ²_p = 0.24–0.76) except rate of force development at 0–90 ms (RFD90) obtained from IsoSqT120 and IsoPress90. A group main effect was observed in RFD90 obtained from IsoSqT120 and IsoPull120 (p = 0.003–0.004, ƞ²_p = 0.37–0.39). Time x Group interaction was observed for 200mTT (p = 0.027, ƞ²_p = 0.68), peak force obtained from IsoSqT90, IsoPress90, and IsoPull120 (p = 0.004–0.006, ƞ²_p = 0.36–0.38) and RFD90 obtained from IsoSqT120 and IsoPull120 (p = 0.012–0.015, ƞ²_p = 0.28–0.30). Inclusion of IST resulted in greater improvement for sprint kayaking and strength performances then TRAD alone.

The purpose of this study was to investigate the effects of soy protein supplementation to improve performance and recovery during repeated running anaerobic sprint test (RAST). Ten males (age: 23.2 ± 1.23 yrs) performed two RAST with a soy milk intervention (SOY; 500 mL soy milk + 4 g stevia sweetener) and a placebo control (CON; 500 mL water + 4 g stevia sweetener) over 7 days. The RAST consisted of six 35-m sprints with a 10-sec recovery between each sprint. The total effort time (sec) was not significant between SOY (32.77 ± 1.23) and CON (33.28 ± 1.71) (P = 0.179). Fatigue index in SOY (31.64 ± 5.20) was significantly lower than CON (37.30 ± 5.70) (P = 0.023). Mean power (Watts) (Soy: 499.27 ± 62.72, Con: 486.39 ± 86.13) (P = 0.410), relative power (Watts) (Soy: 9.34 ± 1.02, Con: 9.55 ± 1.51) (P = 0.461), peak blood lactate (mmol·L-1) (Soy: 9.75 ± 1.61, Con: 10.24 ± 1.90) (P = 0.488), and peak blood glucose (mmol·L-1) (Soy: 23.94 ± 3.90, Con: 25.09 ± 4.61) (P = 0.497) between trials were not significant. Peak blood lactate (r = -0.654) and glucose (r = -0.662) concentrations were inversely associated with mean power in the SOY trial. The results indicate that the soy milk intervention in RAST significantly lowered the fatigue index and, therefore, may be used to enhance sports performance involving anaerobic activities.