Master of Science (Exercise and Sport Studies)

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    Mixed model lower body power training approach on female athletes
    (2023)
    Chua, Kwee Hao
    Recent studies have shown that training at optimal power load (OPL) has positive short and long term effects on athletic performance. The OPL is capable of distinguishing athletes based on various factors such as sports performance levels, disciplines, age, and gender. (Loturco et al., 2022). Mixed model training (MMT) approaches, where training loads vary between sets or sessions, is shown to improve strength and performance in jumping (Hernandez-Davo et al., 2022). By variating training load, coaches are able to better manage fatigue, training adaptation optimization and potentially improve sporting performance (DeWeese et al., 2015). At present, it is unclear which method, either OPL or MMT, would be more beneficial in enhancing physical performance. The objective of this study was to examine if there were any variations in the impact of MMT and OPL training on the physical abilities of female athletes engaged in team sports, specifically focusing on lower limb strength, jumping, sprinting, and change of direction skills. The research involved the involvement of seventeen female representative athletes (average age 22 ± 2.9 years, body mass 60.52 ± 9.62 kg, height 162.69 ± 5.2 cm) who were selected from the Singapore national women softball team. Pre- and post-tests included the isometric mid-thigh pull test, , 5-0-5 change of direction test, countermovement jump test, 20m sprint test and the OPL test. The participants in the study were randomly assigned to either the MMT group or the OPL group. Both groups underwent a six-week training program consisting of two training sessions per week. Participants in the MMT group performed a 20% overload of their individual OPL on day 1 with a 20% underload on day 2. Participants in the OPL group trained at the OPL load on both training days. The findings indicated that there were no notable disparities between the MMT and OPL groups concerning the measurements taken prior to and after the training program. Specifically, the study found no noteworthy differences between the MMT and OPL groups when it came to various measurements such as concentric peak force (MMT 1284 ± 181.80 N to 1270 ± 163.30 N p = 0.228, OPL 1406 ± 208.5 N to 1461 ± 154.6 N p = 0.121), jump height (MMT 31.51 ± 6.12 cm to 31.54 ± 4.263 cm p = 0.98, OPL 28.98 ± 5.594 cm to 28.38 ± 4.965 cm p = 0.417), peak vertical force (MMT 1841 ± 204.10 N to 1818 ± 288.30 N p = 0.617, OPL 1934 ± 256.7 N to 2056 ± 267.5 N p = 0.108), force at 100ms (MMT 884 ± 138.60 N to 924.5 ± 132.60 N p = 0.423, OPL 995.3 ± 209.8 N to 909.9 ± 124.9 N p = 0.184), and rate of force development (MMT 2897 ± 1504 N/s to 3539 ± 1629 N/s p = 0.188, OPL 3093 ± 2004 N/s to 2853 ± 1281 N/s p = 0.572) in the isometric mid-thigh pull test. Additionally, no significant differences were found in the time taken for 5-0-5 change of direction time (MMT 2.547 ± 0.09 s to 2.537 ± 0.13 s p = 0.797, OPL 2.622 ± 0.231 s to 2.594 ± 0.266 s p = 0.525), peak power (MMT 3201 ± 493 W to 3090 ± 556.60 W p = 0.35, OPL 3233 ± 457.8 W to 3314 ± 484.2 W p = 0.589), and 20m sprint time (MMT 3.415 ± 0.25 s to 3.345 ± 0.15 s p = 0.311, OPL 3.483 ± 0.294 s to 3.507 ± 0.285 s p = 0.635) for both groups. Based on this study, significant distinctions were not observed in the pre- and post-test assessments of concentric peak force and jump height during the countermovement jump test. Similarly, no notable differences were found in peak vertical force, force at 100ms, and rate of force development during the isometric mid-thigh pull test, as well as the time taken for the 5-0-5 change of direction test, peak power, and 20m sprint time for both the MMT and OPL groups. There is a notable rise in the OPL load for participants in the OPL condition (31.06 ± 7.08 kg to 39.01 ± 5.63 kg p = 0.012) only. To conclude, this study demonstrated that introducing a variation in load during power training does not result in an enhancement of power output as measured by power-based testing outcomes. With the use of real time data, coaches are encouraged to plan load variations during power training to add friendly competition within the team to enhance training intent and experience.
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    Time use, quality of life and compliance to integrated activity guidelines in adolescent international students
    (2023)
    Yuvaraj Turiahdassu
    This study comprised two parts. The objective of part 1 is to develop a common time use surveillance tool (Adolescent-smalQ) that is appropriate, valid, and reliable for the context of the research. The Association of Medical Education in Europe (AMEE) Guide No. 87 guided the development of Adolescent-smalQ that aimed to examine the prevalence of adolescents in meeting The Singapore Integrated 24-Hour Activity Guidelines for Children and Adolescents. These guidelines include (i) sleep of at least 9 hours (for 7-13 years old), at least 8 hours (for 14-17 years old), and at least 7 hours (for 18 years old), (ii) ≥ 60 minutes of Moderate-to-Vigorous Physical Activity (MVPA) daily, (iii) ≥ 80% adherence to the Singapore Health Promotion Board (HPB) “My Healthy Plate” and (iv) the Canadian 24-hour movement guidelines for recreational Screen Time (ST) of ≤ 2 hours daily. The objective of part 2 is to examine the time use of international schools’ adolescents studying in Singapore and their adherence to the 24-hour integrated activity guidelines and their quality of life. The participants were 555 adolescents (mean age: 15.7 ± 1.4 years, mean Body Mass Index (BMI) of 20.2 ± 3.6, 56.4% female) from two international schools in Singapore. Male and female mean nighttime sleep duration was significantly different on weekdays (7.3 hr vs 6.8 hr, F (1,547) = 18.26, p <.05, partial ŋ2 = .032) but not on weekends (8.6 hr for both genders, F (1, 547) = 0.01, p >.05, partial ŋ2 = .000). However, mean MVPA was significantly different for male and female on weekday (2.2 hr vs 1.8 hr, F (1,547) = 5.26, p <.05, partial ŋ2 = .010), and weekend (1.6 hr vs 1.3 hr, F (1,548) = 15.05, p <.05, partial ŋ2 = .030). No differences were found between male and female mean ST for weekday (6.4 hr vs 6.8 hr, F (1,548) = 2.38, p >.05, partial ŋ2 = .004) and weekend (7.1 hr vs 7.5 hr, F (1,546) = 2.58, p >.05, partial ŋ2 = .005). The prevalence of adolescents meeting all four guidelines (sleep, MVPA, ST and diet) was 6% with 23.6% meeting three and 37.1% meeting at least two guidelines. Meeting all four guidelines was associated with higher mean PedsQLTM score (m = 78.7, 95% CI:74.7, 82.8) compared to meeting none (m = 65.3, 95% CI:59.0, 79.6). In summary, meeting more guidelines was attributed to having a higher mean PedsQLTM score, p=<.05. The correlation between the number of guidelines met and PedsQLTM (total health) score was found to be slightly positive r(555)=.24, p=0.01. Efforts to educate parents, caregivers, educators and adolescents on the importance of the Singapore 24-hour integrated activity guidelines is recommended to promote healthy lifestyle behaviours and increased wellbeing in today's adolescents.
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    Acute effects of using mask during exercise on physiological indices
    (2023)
    Lim, Boon Kwang
    Purpose: Mask confers protection against Coronavirus Disease 2019 (COVID-19) transmission during the pandemic but there are concerns on its use during exercise. Our study sought to broaden existing studies by investigating the impact of use of cloth mask on Time-to-Exhaustion (TTE), physiological indices, OMNI Rate of Perceived Exertion (RPE) and Ratings of Mask Discomfort (RMD) at Lactate Threshold (LT) and Peak Exercise. RMD were measured in 5 different areas: Overall Mask Discomfort (OMD), Breathing Resistance (BR), Hotness Warmness Stuffiness (HWS), Odour or Smelly (OS) and Itchiness (ITCH).

    Methods: Participants were randomised and assigned to either cloth mask (CM) or no mask (NM) condition, to undergo a discontinuous incremental treadmill running protocol. All indices were recorded at the end of each incremental stage. All participants crossover to perform the same test for the other condition at the end of 7-day washout period. Significance of all statistical analysis was set at P < 0.05, unless otherwise stated.

    Results: Wearing of CM significantly affect overall physiological indices, RPE and RMD (P < 0.05). Overall, VO2, OMD, BR, HWS, OS were significantly different for NM and CM conditions (P < 0.05) while Heart Rate (HR) (P = 0.09), blood lactate (P = 0.29), RPE (P = 0.42) and ITCH (P = 0.34) were not significantly different between conditions. At peak exercise, almost all indices [TTE, Maximum Oxygen Uptake (VO2max), HR, lactate, Minute Ventilation (VE), Respiratory Rate (RR), OMD, BR, HWS] were significantly different between conditions (P < 0.05). Only OS and ITCH were not significantly different. At LT, VO2, VE, OMD, BR and HWS indicated significant differences between conditions while the remaining indices (Speed, HR, lactate, RR, RPE, OS and ITCH) did not differ between conditions.

    Conclusion: Amidst significant changes in physiological indices associated with wearing of mask during exercise, there were higher perceptual discomforts though generally tolerable by healthy active population at light intensities to LT. Wearing of CM during exercise at high intensity levels are generally not advisable as almost all indices in our study were significantly different and may potentially cause adverse physiological or physical response. At the same time, this finding presents an opportunity for individuals and exercise practitioners to modify and adapt their programming in achieving training objectives.
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    Biomechanical profile of the snatch in Singapore National Olympic weightlifters
    (2023)
    Ang, Cheng Loong
    Traditionally, kinematic, and kinetic analysis of weightlifting movement is done in a laboratory setting which is hard to implement in a field setting. This study uses a field-based method using in-shoe force sensors and videos to conduct biomechanical profiling of the snatch movement performed by Singapore National Olympic Weightlifters. The participants of the study consist of three male and three female weightlifters (age: 25.17 ± 1.72) that compete in the men’s 67kg (n=1) and 81kg (n=2) weight categories and the female weightlifters compete for the woman’s 49kg (n=1) and 55kg (n=2) weight categories. There were multiple parameters involving the barbell velocity, force, power, and barbell trajectory that were measured in this study. The ground reaction force was measured using in-shoe force sensors loadsol® (novel, Munich, Germany). The trajectory of the barbell was obtained by using the method of video analysis of the snatch attempts performed by the weightlifters. The video was captured using a video camera and analysed using sports analytic software Kinovea (version 0.9.5). Peak and mean measures of velocity, force, and power were calculated using codes written for MATLAB through a 4th order 12 Hz low-pass Butterworth filter. The participants of the study were asked to performed snatches that were at the weight of 80% to 90% of their one repetition maximum that they had achieved during competition, the best three of their snatch attempts were then used for the analysis. The field-based method was able to identify technical differences among the weightlifters from the variability in their trajectory and the deficit in terms of force production and velocity. The data obtained provided some consideration and possible ideas for future training modalities for weightlifters. It also illustrated a practical low-cost and short set-up-time non-lab setting method to measure the kinematics and kinetics of the snatch, providing a platform for future research in the sport of Olympic weightlifting.
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    OMNI rate of perceived exertion color-face scale
    (2022)
    Boey, Peggy Peck Kay
    The OMNI Rate of Perceived Exertion (RPE) scale developed by Robertson is well established as a valid tool to estimate perceived exertion and has been validated with different pictorials and descriptors for different exercise types and age groups. However, a more inclusive single OMNI RPE scale suitable for any age group and exercise type if developed, may increase universal utility.

    Purpose: To develop and validate the OMNI RPE Color-Face Scale (CFS) on healthy male and female adults.

    Methods: A total of 28 healthy participants were recruited for the study which involved two phases – scale development and validation. For the scale development, all participants were given cut-outs of facial illustrations of the picture system, verbal descriptors and color blocks. Participants matched each item to a corresponding RPE value on a vertical 0 – 10 scale and semantic differential analysis (SDA) was used to determine the appropriate descriptors. In the validation segment, participants were randomly assigned to either experimental (EG) or control group (CG). They completed two laboratory and one outdoor session. The OMNI RPE CFS and OMNI RPE Adult- Walk/run scale was used by EG and CG respectively. In the estimation trial (ET), participants ran a discontinuous graded submaximal treadmill test that involved a 4- minute work-rest cycle. Treadmill gradient was maintained at 1% throughout and speed increased at 0.5km·h-1 per work stage. In the production trial (PT), participants ran three counterbalanced trials (RPE 2, 5 and 7) for 8-minute each. Participants had 3-minutes to adjust the speed and maintain their self-selected speed for the next 5-minutes. Between each trial was a 1-minute active rest at 1km·h-1 with treadmill gradient at 1%. In ET and PT, heart rate (HR) and RPE were recorded during each work stage. In the 3rd session, participants played a two-a-side 30-minutes (5-minutes warm-up, 20-minutes game and 5-minutes cool down) modified soccer game. Participants had to regulate their perceived exertion at RPE 1 – 4 for both warm-up and cool down, and RPE 5 – 7 during the game. RPE and HR were recorded after each segment.

    Results: SDA revealed no further changes needed to the pre-designed OMNI RPE CFS. Ventilatory breakpoint (Vpt) was identified at 69.44% for the cohort. Normalized RPE for Vpt was identified at RPE 5. Concurrent validity was obtained with strong positive correlation with OMNI RPE Adult-Walk/run scale for VO2 (r = 0.80, p = 0.00) and HR (r = 0.69, p = 0.00). Construct validity indicated positive linear regression of OMNI RPE CFS against OMNI RPE Adult-Walk/run scale (r = 0.88, p = 0.00). Prescription congruence was attained with no significant difference between ET and PT in HR (p = 0.49) and VO2 (p = 0.97) by cohort. Intensity discrimination indicated significant difference in VO2 (p = 0.65) and HR (p = 0.86) between each increasing RPE during PT. Significant differences was obtained from warm up and cool down with activity in HR (p = 0.17) and RPE (p = 0.05) .

    Conclusion: Validation of the OMNI RPE CFS was well established with the validation criteria of OMNI RPE CFS for self-regulation. Validation during outdoor games field settings was also established.
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