Browsing by Author "Coetsee, Carla"

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    The effect of three different exercise training modalities on cognitive and physical function in a healthy older population
    (Biomed Central, 2017-08) Coetsee, Carla; Terblanche, Elmarie
    Background Older adults are encouraged to participate in regular physical activity to counter the age-related declines in physical and cognitive health. Literature on the effect of different exercise training modalities (aerobic vs resistance) on these health-related outcomes is not only sparse, but results are inconsistent. In general, it is believed that exercise has a positive effect on executive cognitive function, possibly because of the physiological adaptations through increases in fitness. Indications are that high-intensity interval training is a potent stimulus to improve cardiovascular fitness, even in older adults; however, its effect on cognitive function has not been studied before. Therefore, the purpose of this study was to compare the effects of resistance training, high-intensity aerobic interval training and moderate continuous aerobic training on the cognitive and physical functioning of healthy older adults. Methods Sixty-seven inactive individuals (55 to 75 years) were randomly assigned to a resistance training (RT) group (n = 22), high-intensity aerobic interval training (HIIT) group (n = 13), moderate continuous aerobic training (MCT) group (n = 13) and a control (CON) group (n = 19) for a period of 16 weeks. Cognitive function was assessed with a Stroop task and physical function with the Timed-Up-and-Go (TUG) and submaximal Bruce treadmill tests. Results No significant GROUP x TIME interaction was found for Stroop reaction time (P > .05). The HIIT group showed the greatest practical significant improvement in reaction time on the information processing task, i.e. Stroop Neutral (ES = 1.11). MCT group participants had very large practical significant improvements in reaction time on the executive cognitive tasks, i.e. Stroop Incongruent and Interference (ES = 1.28 and 1.31, respectively). The HIIT group showed the largest practically significant increase in measures of physical function, i.e. walking endurance (ES = 0.91) and functional mobility (ES = 0.36). Conclusions MCT and RT proved to be superior to HIIT for the enhancement of older individuals’ executive cognitive function; whereas HIIT were most beneficial for improvement in information processing speed. HIIT also induced the largest gains in physical function.
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    The relation of exercise training mode, brain oxygenation and cognition in healthy older adults
    (Stellenbosch : Stellenbosch University, 2015-12) Coetsee, Carla; Terblanche, Elmarie; Stellenbosch University. Faculty of Education. Dept. of Sport Science.
    ENGLISH ABSTRACT: Background: Physical exercise has been shown to prevent cognitive decline and dementia in later life and is generally proposed as a non-pharmacological treatment to reverse or delay the age-related deteriorations in physical and cognitive health. However, it is unknown how different types of exercise will compare with regards to gains in older individuals’ physical and cognitive function and, in particular, the role of high-intensity interval training, has not been extended to the cognitive function literature. Aims: The purpose of this thesis was to determine the effects of three different exercise training modalities (resistance training, high-intensity interval training and moderate continuous training) on physical and cognitive function, as well as cerebral oxygenation. Methods: Sixty seven inactive individuals (55 to 75 years) volunteered for this intervention study. Participants were allocated to a resistance training (RT) group (n=22), high-intensity interval training (HIIT) group (n=13), moderate continuous training (MCT) group (n=13) and a control (CON) group (n=19). Each training group performed three supervised exercise sessions per week over a period of 16 weeks. Cognitive function was assessed every four weeks with a computerized Stroop task, while physical function was assessed with the Timed-Up-and-Go (TUG) and submaximal Bruce treadmill tests. Changes in cerebral oxygenation during the Stroop task were measured at baseline and after the 16-week intervention period. Furthermore, muscle strength was assessed in the CON and RT groups with 10RM leg and bench press tests. The RT and CON groups repeated their baseline measurements after a subsequent 16-week detraining (DET) period. Results: Upper and lower body strength generally improved significantly after every four weeks of RT (with an increase after 16 weeks of 7.3 ± 4.9 kg and 86.6 ± 44.4 kg, respectively; P < 0.001), while TUG performance (-0.2 ± 0.4 s; P < 0.05) and submaximal endurance capacity (0.7 ± 0.9 min; P < 0.001) only improved after 16 weeks. Although muscle strength decreased after detraining, it remained at a level higher than baseline (P < 0.05). Submaximal endurance capacity improved after DET (P < 0.001), while TUG performance returned to baseline. The HIIT group showed a greater improvement in TUG performance (-0.3 ± 0.4 s; ES = 0.36) and walking endurance (1.4 ± 1.3 min; ES = 0.91) compared to RT and MCT. Within each group only RT showed statistically significant improvements, with HIIT and MCT presenting the same trend, beyond the 4-week intervention period, on the measures of executive cognitive function (ES > 0.70). The brain oxygenation results revealed higher relative O2Hb values in CON during the simple and complex Stroop tasks at the post-test compared to the pre-test values (P < 0.05), as well as compared to all three exercise training groups (P < 0.05). Conclusion: Increases in muscular and physical function in older individuals were not induced in a concurrent manner over the course of a RT programme. Furthermore, older adults retained a significant amount of muscle strength and submaximal endurance capacity after a period of DET, while functional mobility was completely reversed. HIIT proved to be most beneficial for the enhancement of older individuals’ aerobic fitness. Exercise training proved more beneficial for the enhancement of executive cognitive function compared to no training. It was also demonstrated that exercise training, independent of the mode, results in more efficient cerebral oxygenation during cortical activation, whereas HIIT and MCT proved to be superior to RT for task-efficient cerebral oxygenation and improved oxygen utilization during cortical activation in older individuals.
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    The time course of changes induced by resistance training and detraining on muscular and physical function in older adults
    (BioMed Central, 2015-10) Coetsee, Carla; Terblanche, Elmarie
    Background: It is generally recognised that the physical functioning of older adults is enhanced with resistance exercise. The aim of this study was to investigate the time course of changes in upper and lower body muscle strength and physical function in older individuals following a 16 week resistance training (RT) programme and a similar duration detraining (DET) period. Methods: Forty-one inactive individuals (55 to 75 years) were randomly allocated in a RT group (n = 22; three sessions per week) and a control (CON) group (n = 19). Muscle strength was assessed with 10RM leg and bench press tests, while the Timed-Up-and-Go (TUG) test was used to measure functional mobility. The Bruce treadmill test determined the participants’ submaximal endurance capacity. Data were analysed using mixed model repeated measures ANOVA and P < 0.05 was considered statistically significant. Results: Main treatment effects were found for muscle strength (P < 0.001) and functional mobility (P < 0.05). Upper and lower body strength generally showed a statistically significant improvement after every 4 weeks in RT (the increase after 16 weeks being 7.3 ± 4.9 kg and 86.6 ± 44.4 kg, respectively; P < 0.001) while TUG performance (−0.2 ± 0.4 s; P < 0.05) and submaximal endurance capacity (0.7 ± 0.9 min; P < 0.001) only improved after 16 weeks. Although muscle strength decreased after DET, it was still better than at baseline. No significant improvements in any performance variable were observed in CON directly after the intervention period (0–16 weeks) (P > 0.05). Conclusion: A 16-week RT programme has positive effects on both muscular and physical function in older adults, although the time course of these adaptations is different. While the gains in muscle strength and submaximal endurance capacity were not totally lost after DET, functional mobility was completely reversed. Older adults can be reassured that if the need arises to discontinue RT for a certain period they will still retain a large amount of their acquired muscle strength, as well as a degree of physical function such as submaximal endurance capacity. The association between leg strength and submaximal endurance capacity strengthens the notion that RT should be incorporated in training and rehabilitation programmes of ageing and frail older adults.