Browsing by Author "Balasekaran, Govindasamy"
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- Arm-pull thrust in human swimming and the effect of post-activation potentiationPublication . Barbosa, Tiago M.; Yam, Jia Wen; Balasekaran, Govindasamy; Marinho, D.A.The aim of this study was to analyse the front-crawl arm-pull kinetics and kinematics, comparing it before and after post-activation potentiation (PAP), and the associations between variables describing of the arm-pull kinetics. Twelve male competitive swimmers were randomly assigned to perform two different warm-ups in a crossover manner: (i) non-PAP (control condition); and (ii) PAP (experimental condition). PAP consisted of 2 × 5 arm-pulls with resistance bands by both upper-limbs. Eight minutes later, participants underwent a 25 m all-out trial in front-crawl arm-pull. Kinetics (i.e., peak thrust, mean thrust and thrust-time integral) and kinematics (i.e., speed and speed fluctuation) were collected by an in-house customised system composed of differential pressure sensors, speedo-meter and underwater camera. There was a significant and large improvement of the arm-pull kinetics after completing the warm-up with PAP sets (0.010 < P < 0.054, 0.50 < d < 0.74). There were non-significant and small effects of PAP on speed (P = 0.307, d = 0.18) and speed fluctuation (P = 0.498, d = 0.04). Correlation coefficients among kinetic variables were significant with large associations (0.51 < R < 0.90, 0.001 < P < 0.088). In conclusion, warm-ups including PAP conditioning sets elicit a large improvement in the thrust, but with small improvement in performance.
- Comparing the effects of plyometric and isometric strength training on dynamic and isometric force-time characteristicsPublication . Lum, Danny; Comfort, Paul; Barbosa, Tiago M.; Balasekaran, GovindasamyThe 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.
- Effects of isometric strength and plyometric training on running performance: a randomized controlled studyPublication . Lum, Danny; Barbosa, Tiago M.; Aziz, Abdul Rashid; Balasekaran, GovindasamyThe 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 center dot kg(-1)center dot 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, n(p)(2) = .45 and P < .001, n( )(2)=0.72), maximal aerobic speed (MAS) (P = .006, n(p)(2) = .39), CMJ height (P < .001, n(p)(2) = .55) and IMTP relative peak force (P = .001, n(p)(2) = .50) in favor of PT and IST. Significant main effect for time was observed for 2.4kmTT (P < .001, n(p)(2) = .72), RE (P = .048, n(p)(2) = .17), VO2max (P = .047, n(p)(2) = .18), MAS (P < .001, n(p)(2) = .63), CMJ height (P < .001, n(p)(2) = .51) and IMTP relative peak force (P < .001, n(p)(2) = .58). Conclusion: In conclusion, both PT and IST were similarly effective at enhancing running endurance performance. However, IST resulted in greater improvement to RE.
- Effects of mental fatigue on maximal exercise test performance in physically active and sedentary adultsPublication . Tou, Nien Xiang; Balasekaran, Govindasamy; Barbosa, Tiago M.This study examined the effects of mental fatigue on maximal treadmill walking exercise performance. METHODS: 50 young male (n = 25) and female (n = 25) adults were recruited to perform a maximal treadmill walking exercise test to volitional exhaustion on two occasions. Prior to the exercise test, participants performed a cognitive task in a randomized, counterbalanced manner for 30 minutes, with the incongruent Stroop task in the mental fatigue condition, and leisure magazine reading in the control condition. Subjective ratings of perceived mood, fatigue, and motivation to exercise were assessed before and after the cognitive task. Perceptual and physiological responses were collected throughout the exercise test.
- Effects of two isometric strength training methods on jump and sprint performances: a randomized controlled trialPublication . Lum, Danny; Barbosa, Tiago M.; Joseph, Ranald; Balasekaran, GovindasamyIsometric strength training (IST) with rapid non-sustained contraction (RIST) is effective in improving the ability to generate force rapidly. However, the neuromuscular adaptation of IST with sustained contraction (SIST) and RIST is not known. Therefore, the aim of the study was to compare the neuromuscular adaptations of RIST with SIST. Methods Thirty-three national floorball players (23.9 ± 3.1 years old; 1.69 ± 0.08 m; 64.6 ± 11.1 kg) were recruited for this study. Pre- and post-test included countermovement jump (CMJ), 30-m sprint (TT30), isometric squat at 90° (ISqT90) and 120° (ISqT120) knee angles. They were randomly assigned to either control (Con) (n = 9), RIST (n = 12) or SIST (n = 12) group and performed 12 sessions of intervention training. All groups performed the same sets of exercises, but RIST and SIST had to perform ISqT with and without sustained contraction, respectively. Results Time × group effect for CMJ height (P = 0.01, ƞp 2 = 0.25), peak force (PF) (P = 0.03, ƞp 2 = 0.22) and rate of force development (RFD) (P = 0.02, ƞp 2 = 0.22) obtained from ISqT120 were noted. A main effect for time was observed in CMJ height, PF obtained from ISqT90 and ISqT120, and RFD obtained from ISqT90 (P < 0.01, 0.27 < ƞp 2 < 0.57). There was greater improvement in TT30 (P = 0.043, d = 3.00), ISqT90 PF (P = 0.034, d = 3.12), ISqT120 PF (P = 0.003, d = 4.54) and ISqT120 RFD (P = 0.033, d = 1.36) in the SIST than the Con group. Conclusion SIST was more effective in improving strength and dynamic performance as compared to RIST, making it a viable training method to enhance dynamic performances.
- Influence of exercise experience on perception of prescribed and preferred exercise intensityPublication . Tou, Nien Xiang; Balasekaran, Govindasamy; Barbosa, Tiago M.Perception plays a key role in self-regulationof exercise intensity
- Sprint kayaking performance enhancement by isometric strength training inclusion: a randomized controlled trialPublication . Lum, Danny; Barbosa, Tiago M.; Balasekaran, GovindasamyPerforming 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 preand 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 90º knee angle, while IsoPress and IsoPull were performed at 90º and 120º elbow angles, respectively.
- The measurement of thrust in competitive swimming: the association between different thrust variablesPublication . Barbosa, Tiago M.; Yam, Jia Wen; Balasekaran, Govindasamy; Marinho, D.A.Swimming acceleration and velocity are the net balance between Drag Force and Thrust
- The measurement of thrust in competitive swimming: the association between different thrust variablesPublication . Barbosa, Tiago M.; Yam, Jia Wen; Balasekaran, Govindasamy; Marinho, D.A.Swimming acceleration and velocity are the net balance betwen drag force and thrust.