International SportMed Journal - Volume 13, Issue 3, 2012
Volume 13, Issue 3, 2012
Oxidative stress response to isometric exercise in women : effect of age and exercise intensity : original research articleSource: International SportMed Journal 13, pp 85 –95 (2012)More Less
Objective: The effects of exercise intensity and age on oxidative stress induced by isometric exercise were investigated. Methods: Sixteen women (8 old: O, and 8 young: Y) performed two isometric protocols (30% and 50% maximal voluntary isometric contraction, MVIC). Results: Blood lactate changed significantly from immediately after to 10-min post-exercise in group Y at both intensities. Values differed significantly between Y and O groups only at 1-min post-exercise at 30% and 50% MVIC. No significant changes occurred in thiobarbituric reactants or reduced ascorbic acid. The oxidised/reduced glutathione ratio increased significantly from 1-min to 10-min post-exercise in both groups at 50% MVIC, and at 30% MVIC in group Y. Values increased significantly from 3-min to 10-min post-exercise in group O at 30% MVIC. Conclusions: Exercise intensity and age had no significant effect on oxidative stress response after wrist-flexor isometric exercise, and the glutathione system could provide a sufficient defence against oxidative damage.
The immediate effect of wheelchair Tai Chi on autonomic nervous modulation in subjects with chronic spinal cord injury : a pilot study : original research articleSource: International SportMed Journal 13, pp 96 –108 (2012)More Less
Objective: Alteration of autonomic nervous activities has been reported in subjects with spinal cord injury (SCI). It is not clear whether wheelchair Tai Chi (WTC) can enhance the balance of autonomic nervous activities in chronic SCI. Participants:Ten chronic, complete or incomplete SCI patients (i.e. five C3-C6 injured tetraplegics and five T4-T12 injured paraplegics) were recruited. Intervention: The subjects took eight weeks to learn the WTC exercise (60 minutes per session, 3 sessions per week). Then the heart rate variability (HRV) was recorded by means of a handheld HRV device (DailyCare BioMedical, Inc. Taiwan) in trained subjects before and after performing WTC in a single session (about 40 minutes). Results: There was no significant decrease in the time domain of HRV following WTC exercise. However, the frequency domain indicated that the normalized high frequency (HFnu) increased significantly from 27.5 to 39.0 (p = 0.022), and the normalized low frequency (LFnu), HF peak and LF/HF decreased LF/HF decreased LF/HF decreased LF/HF decreasedLF/HF decreased LF/HF decreasedLF/HF decreasedLF/HF decreased significantly in SCI. Conclusion: The short-term WTC with slow breathing might enhance vagal activity and decrease sympathetic activity with balanced sympathovagal tone in chronic subjects following complete or incomplete SCI.
Effect of caffeine intake on blood pressure and heart rate variability after a single bout of aerobic exercise : original research articleSource: International SportMed Journal 13, pp 109 –121 (2012)More Less
Background: The consumption of a dose of caffeine (CAF) may attenuate post-exercise hypotension. Research question: The purpose was to verify the effect of a dose of CAF on systolic (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR) and heart rate variability (HRV) after a session of aerobic exercise in normotensive individuals. Type of study: Randomized controlled study. Methods: Ten healthy, physically active men (24.4 ± 4.5yrs; 74.3 ± 11.8kg; 172.8 ± 8.6m; 36.8 ± 5.7ml.kg-1.min-1) were randomly submitted to two experimental protocols in distinct days, in a cross-over double-blind design, with the ingestion of 4mg.kg-1of CAF or placebo and performance of an aerobic exercise in a cycle ergometer at 60% VO2peak. SBP, DBP, MAP, HR and HRV components were assessed at the pre-exercise rest period, 60 min after substance ingestion and during 60min post-exercise. Results: At the post-ingestion period, there were reductions on basal HR on both sessions and mean rises of 5mmHg on SBP, of 7-8mmHg on DBP and of 6-7mmHg on MAP on the caffeine session. After exercise, there were reductions of 5-7mmHg on SBP, significant on the 30th and 40th min, on the placebo session. During the caffeine session, maintenance of raised HR levels, no difference in relation to the pre-exercise period for SBP and MAP, and higher blood pressure compared to the placebo session. HRV was altered in each session; however there were no differences between the experimental sessions. Conclusion: The ingestion of a 4mg.kg-1dose of CAF apparently does not significantly interfere on the cardiovascular behaviour after a session of aerobic exercise.
Sagittal spinal curvatures and pelvic tilt in cyclists : a comparison between two master cyclist categories : original research articleSource: International SportMed Journal 13, pp 122 –132 (2012)More Less
Background: Sagittal spinal curvatures and pelvic tilt in master cyclists may be altered due to specific cyclists' postures. Research question: To analyse and compare the spinal and pelvic postures, between two cyclist age-categories with different cycling experience. Type of study: Descriptive and comparative. Methods:Participants: Fifty-five master 30 cyclists (between 30 and 39 years of age) and 55 master 40 cyclists (between 40 and 49 years of age). Main measures of outcome: Sagittal spinal curvatures and pelvic tilt in relaxed standing, slumped sitting and a sit-and-reach test were measured using a Spinal Mouse® system. Results: Greater lumbar lordosis and anterior pelvic tilt in standing were found in master 30 cyclists (p < 0.05). However, no differences were found in the thoracic spine between both groups in standing. Seated thoracic kyphosis was lower in master 30 cyclists than in master 40 cyclists (p < 0.01). Kyphotic lumbar postures and posterior pelvic tilting in both groups were found in the slumped sitting and the sit-and-reach test. A high percentage of thoracic hyperkyphosis and neutral lordosis in standing were found in both groups. Conclusion: Both cyclists' categories presented a high percentage of hyperkyphosis thoracic in the standing posture, and master 40 cyclists showed a significantly lower lumbar lordosis and anterior pelvic tilt than master 30 cyclists. In the seated position, middle-aged cyclists presented a significantly higher thoracic kyphosis than younger cyclists, although in maximal trunk flexion with knees extended, both groups presented similar values.
Comparison of rates of perceived exertion between active video games and traditional exercise : original researchAuthor Julie DevereauxSource: International SportMed Journal 13, pp 133 –140 (2012)More Less
Background: Research regarding the Nintendo WiiTM has focused on rehabilitation and balance benefits as well as energy expenditure for games such as boxing and tennis. There is a gap, however, in the literature regarding perceived exertion of the WiiTM compared to other modes of exercise. Research question:The purpose of this laboratory-based study was to compare perceived exertion on the Nintendo WiiTM and two traditional modes of exercise : the treadmill and cycle ergometer. It was expected that the WiiTM would show lower ratings of perceived exertion (RPE) values. Type of study: A repeated measures design was used. Methods: Five healthy males (average age = 21.4 years) and seven females (average age = 22.1 years) completed three 20 minute exercise sessions in random order, one each using the cycle ergometer, the treadmill and the Nintendo Wii Fit PlusTM. Exercise intensity was fixed at 65% (± 5 bpm) of each participant's age predicted maximum heart rate. Ratings of perceived exertion and HR were measured every minute. Additionally overall RPE was collected at the end of each trial. Results: Repeated measures analysis of variance confirmed that although exercise intensity was consistent across the three exercise methods, overall RPE was lowest for the Nintendo WiiTM (9.50) followed by the treadmill (9.92) and finally the cycle ergometer (11.08), F(1,11) = 10.17, p<0.01. Conclusions: When compared to certain traditional exercise modalities the Nintendo Wii Fit PlusTM was perceived to require less effort. Therefore, using the Nintendo Wii Fit PlusTM is likely to result in higher exercise adherence rates.