Caffeine has a small effect on 5-km running performance of well-trained and recreational runners
- O'Rourke, Matthew, O'Brien, Brendan, Knez, Wade, Paton, Carl
- Authors: O'Rourke, Matthew , O'Brien, Brendan , Knez, Wade , Paton, Carl
- Date: 2008
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 11, no. 2 (2008), p. 231-233
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- Description: The purpose of this study was to investigate if caffeine ingestion improves 5-km time-trial performance in well-trained and recreational runners. Using a double-blind placebo-controlled design, 15 well-trained and 15 recreational runners completed two randomized 5-km time-trials, after ingestion of either 5 mg kg-1 of caffeine or a placebo. Caffeine ingestion significantly improved 5-km running performance in both the well-trained and recreational runners. In comparison to the placebo trial, the caffeine trial resulted in 1.1% (90% CI 0.4-1.6) and 1.0% (0.2-2%) faster times for the well-trained and recreational runners. Reliability testing of the recreational runners indicated a test-retest error of measurement of 1.4%. We conclude that caffeine ingestion is likely to produce small but significant gains in 5-km running performance for both well-trained and recreational runners. © 2007 Sports Medicine Australia.
- Description: C1
- Authors: O'Rourke, Matthew , O'Brien, Brendan , Knez, Wade , Paton, Carl
- Date: 2008
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 11, no. 2 (2008), p. 231-233
- Full Text:
- Reviewed:
- Description: The purpose of this study was to investigate if caffeine ingestion improves 5-km time-trial performance in well-trained and recreational runners. Using a double-blind placebo-controlled design, 15 well-trained and 15 recreational runners completed two randomized 5-km time-trials, after ingestion of either 5 mg kg-1 of caffeine or a placebo. Caffeine ingestion significantly improved 5-km running performance in both the well-trained and recreational runners. In comparison to the placebo trial, the caffeine trial resulted in 1.1% (90% CI 0.4-1.6) and 1.0% (0.2-2%) faster times for the well-trained and recreational runners. Reliability testing of the recreational runners indicated a test-retest error of measurement of 1.4%. We conclude that caffeine ingestion is likely to produce small but significant gains in 5-km running performance for both well-trained and recreational runners. © 2007 Sports Medicine Australia.
- Description: C1
Do physical capacity and interchange rest periods influence match exercise-intensity profile in Australian football?
- Mooney, Mitchell, Cormack, Stuart, O'Brien, Brendan, Coutts, Aaron
- Authors: Mooney, Mitchell , Cormack, Stuart , O'Brien, Brendan , Coutts, Aaron
- Date: 2013
- Type: Text , Journal article
- Relation: International Journal of Sports Physiology and Performance Vol. 8, no. 2 (2013), p. 165-172
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- Description: Purpose: The purpose of this study was to determine if Yo-Yo Intermittent Recovery level 2 (Yo-Yo IR2) and the number of interchange rotations affected the match activity profile of elite Australian footballers. Method: Fifteen elite Australian footballers completed the Yo-Yo IR2 before the beginning of the season and played across 22 matches in which match activity profiles were measured via microtechnology devices containing a global positioning system (GPS) and accelerometer. An interchange rotation was counted when a player left the field and was replaced with another player. Yo-Yo IR2 results were further split into high and low groups. Results: Players match speed decreased from 1st to 4th quarter, while average-speed (m/min: P = .05) and low-speed activity (LSA, <15 km/h) per minute (LSA m/min; P = .06) significantly decreased in the 2nd half. Yo-Yo IR2 influenced the amount of m/min, high-speed running (HSR, >15 km/h) per minute (HSR m/min) and accelerometer load/min throughout the entire match. The number of interchanges significantly influenced the HSR m/min and m/min throughout the match except in the 2nd quarter. Furthermore, the low Yo-Yo IR2 group had significantly less LSA m/min in the 4th quarter than the high Yo-Yo IR2 group (92.2 vs 96.7 m/ min, P = .06). Conclusions: Both the Yo-Yo IR2 and number of interchanges contribute to m/min and HSR m/min produced by elite Australian footballers, affecting their match activity. However, while it appears that improved Yo-Yo IR2 performance prevents reductions in LSA m/min during a match, higher-speed activities (HSR m/min) and overall physical activity (m/min and load/min) are still reduced in the 4th quarter compared with the 1st quarter. © 2013 Human Kinetics, Inc.
- Description: 2003010859
- Authors: Mooney, Mitchell , Cormack, Stuart , O'Brien, Brendan , Coutts, Aaron
- Date: 2013
- Type: Text , Journal article
- Relation: International Journal of Sports Physiology and Performance Vol. 8, no. 2 (2013), p. 165-172
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- Description: Purpose: The purpose of this study was to determine if Yo-Yo Intermittent Recovery level 2 (Yo-Yo IR2) and the number of interchange rotations affected the match activity profile of elite Australian footballers. Method: Fifteen elite Australian footballers completed the Yo-Yo IR2 before the beginning of the season and played across 22 matches in which match activity profiles were measured via microtechnology devices containing a global positioning system (GPS) and accelerometer. An interchange rotation was counted when a player left the field and was replaced with another player. Yo-Yo IR2 results were further split into high and low groups. Results: Players match speed decreased from 1st to 4th quarter, while average-speed (m/min: P = .05) and low-speed activity (LSA, <15 km/h) per minute (LSA m/min; P = .06) significantly decreased in the 2nd half. Yo-Yo IR2 influenced the amount of m/min, high-speed running (HSR, >15 km/h) per minute (HSR m/min) and accelerometer load/min throughout the entire match. The number of interchanges significantly influenced the HSR m/min and m/min throughout the match except in the 2nd quarter. Furthermore, the low Yo-Yo IR2 group had significantly less LSA m/min in the 4th quarter than the high Yo-Yo IR2 group (92.2 vs 96.7 m/ min, P = .06). Conclusions: Both the Yo-Yo IR2 and number of interchanges contribute to m/min and HSR m/min produced by elite Australian footballers, affecting their match activity. However, while it appears that improved Yo-Yo IR2 performance prevents reductions in LSA m/min during a match, higher-speed activities (HSR m/min) and overall physical activity (m/min and load/min) are still reduced in the 4th quarter compared with the 1st quarter. © 2013 Human Kinetics, Inc.
- Description: 2003010859
Four weeks of sprint interval training improves 5-km run performance
- Denham, Joshua, Feros, Simon, O'Brien, Brendan
- Authors: Denham, Joshua , Feros, Simon , O'Brien, Brendan
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 29, no. 8 (2015), p. 2137-2141
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- Description: Sprint interval training (SIT) rapidly improves cardiorespiratory fitness but demands less training time and volume than traditional endurance training. Although the health and fitness benefits caused by SIT have received considerable research focus, the effect of short-term SIT on 5-km run performance is unknown. Thirty healthy untrained participants (aged 18-25 years) were allocated to a control (n = 10) or a SIT (n = 20) group. Sprint interval training involved 3-8 sprints at maximal intensity, 3 times a week for 4 weeks. Sprints were progressed to 8 by the 12th session. All participants completed a 5-km time trial on a public running track and an incremental treadmill test in an exercise physiology laboratory to determine 5-km run performance and maximum oxygen uptake, respectively, before and after the 4-week intervention. Relative to the controls, sprint interval-trained participants improved 5-km run performance by 4.5% (p < 0.001), and this was accompanied by improvements in absolute and relative maximum oxygen uptake (4.9%, p 0.04 and 4.5%, p = 0.045, respectively). Therefore, short-term SIT significantly improves 5-km run performance in untrained young men. We believe that SIT is a time-efficient means of improving cardiorespiratory fitness and 5-km endurance performance. © 2015 National Strength and Conditioning Association.
- Authors: Denham, Joshua , Feros, Simon , O'Brien, Brendan
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 29, no. 8 (2015), p. 2137-2141
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- Description: Sprint interval training (SIT) rapidly improves cardiorespiratory fitness but demands less training time and volume than traditional endurance training. Although the health and fitness benefits caused by SIT have received considerable research focus, the effect of short-term SIT on 5-km run performance is unknown. Thirty healthy untrained participants (aged 18-25 years) were allocated to a control (n = 10) or a SIT (n = 20) group. Sprint interval training involved 3-8 sprints at maximal intensity, 3 times a week for 4 weeks. Sprints were progressed to 8 by the 12th session. All participants completed a 5-km time trial on a public running track and an incremental treadmill test in an exercise physiology laboratory to determine 5-km run performance and maximum oxygen uptake, respectively, before and after the 4-week intervention. Relative to the controls, sprint interval-trained participants improved 5-km run performance by 4.5% (p < 0.001), and this was accompanied by improvements in absolute and relative maximum oxygen uptake (4.9%, p 0.04 and 4.5%, p = 0.045, respectively). Therefore, short-term SIT significantly improves 5-km run performance in untrained young men. We believe that SIT is a time-efficient means of improving cardiorespiratory fitness and 5-km endurance performance. © 2015 National Strength and Conditioning Association.
Immediate re-hydration post-exercise is not coincident with raised mean arterial pressure over a 30-minute observation period
- Kay, Bartholomew, O'Brien, Brendan, Gill, Nicholas
- Authors: Kay, Bartholomew , O'Brien, Brendan , Gill, Nicholas
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Sports Science and Medicine Vol. 4, no. 4 (Dec 2005), p. 422-429
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- Description: This investigation assessed the effects of immediate or delayed re-hydration post-exercise, on mean arterial blood pressure ( MAP) and on blood plasma volume (PV) expansion post-exercise. It was hypothesised that fluid ingestion would raise MAP and attenuate PV expansion. On two occasions separated by seven days, eight males ( age 20.4 +/- 1.7 years, mass 79 +/- 5 kg [ means +/- SD]; VO2 max 48 +/- 11 mL center dot kg(-1) center dot minute(-1), [mean +/- SE]) cycled in the heat (35 degrees C, 50% relative humidity) at a power output associated with 50% VO2 max, until 1.0kg body mass was lost. 1L water was given either immediately thereafter, or two hours post-exercise by random assignment. On both occasions, MAP was calculated every five minutes for a period of 30-minutes post-exercise, and change in PV was calculated 24-hours post-exercise. Repeated measures ANOVA for MAP results suggested a low probability of a treatment effect ( p = 0.655), a high probability of a time effect ( p = 0.006), and a moderately high probability of a time x treatment interaction ( p = 0.076); MAP tended to be lower when fluid had been consumed. PV expansions 24-hours post-exercise were not significant changes with respect to zero, and were not significantly different by treatment condition. In conclusion: ( a) The exercise was not sufficient to elicit significant PV expansions; thus, we were unable to determine the effects of the timing of post-exercise re-hydration on PV expansion. (b) The hypothesis regarding MAP in response to drinking was not supported, rather there was a 92% probability that the inverse affect occurs.
- Description: C1
- Description: 2003002930
- Authors: Kay, Bartholomew , O'Brien, Brendan , Gill, Nicholas
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Sports Science and Medicine Vol. 4, no. 4 (Dec 2005), p. 422-429
- Full Text:
- Reviewed:
- Description: This investigation assessed the effects of immediate or delayed re-hydration post-exercise, on mean arterial blood pressure ( MAP) and on blood plasma volume (PV) expansion post-exercise. It was hypothesised that fluid ingestion would raise MAP and attenuate PV expansion. On two occasions separated by seven days, eight males ( age 20.4 +/- 1.7 years, mass 79 +/- 5 kg [ means +/- SD]; VO2 max 48 +/- 11 mL center dot kg(-1) center dot minute(-1), [mean +/- SE]) cycled in the heat (35 degrees C, 50% relative humidity) at a power output associated with 50% VO2 max, until 1.0kg body mass was lost. 1L water was given either immediately thereafter, or two hours post-exercise by random assignment. On both occasions, MAP was calculated every five minutes for a period of 30-minutes post-exercise, and change in PV was calculated 24-hours post-exercise. Repeated measures ANOVA for MAP results suggested a low probability of a treatment effect ( p = 0.655), a high probability of a time effect ( p = 0.006), and a moderately high probability of a time x treatment interaction ( p = 0.076); MAP tended to be lower when fluid had been consumed. PV expansions 24-hours post-exercise were not significant changes with respect to zero, and were not significantly different by treatment condition. In conclusion: ( a) The exercise was not sufficient to elicit significant PV expansions; thus, we were unable to determine the effects of the timing of post-exercise re-hydration on PV expansion. (b) The hypothesis regarding MAP in response to drinking was not supported, rather there was a 92% probability that the inverse affect occurs.
- Description: C1
- Description: 2003002930
Plasma volume expansion 24-hours post-exercise: Effect of doubling the volume of replacement fluid
- Kay, Bartholomew, O'Brien, Brendan, Gill, Nicholas
- Authors: Kay, Bartholomew , O'Brien, Brendan , Gill, Nicholas
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Sports Science and Medicine Vol. 4, no. 2 (2005), p. 179-184
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- Description: The effects of two volumes (1.5 L or 3.0 L) of commercially available electrolyte beverage (1.44 mM·L-1 Na+) taken during a 24-hour recovery period post-exercise, on plasma volume (PV) expansion 24-hours post-exercise were assessed. A simple random-order crossover research design was used. Subjects (n = 9 males: age 21 ± 4 years, body mass 80.0 ± 9.0 kg, peak incremental 60-second cycling power output 297 ± 45 W [means ± SD]) completed an identical exercise protocol conducted in hot ambient conditions (35°C, 50% relative humidity) on two occasions; separated by 7-days. On each occasion, subjects received a different volume of 24-hour fluid intake (commercial beverage) in random order. In each case, the fluid was taken in five equal aliquots over 24-hours. PV expansions 24-hours post-exercise were estimated from changes in haemoglobin and haematocrit. Dependent t-testing revealed no significant differences in PV expansions between trials, however a significant expansion with respect to zero was identified in the 3.0 L trial only. Specifically, PV expansions (%) were; 1.5 L trial: (mean ± SE) 2.3 ± 2.0 (not significant with respect to zero), 3.0 L trial: 5.0 ± 2.0 (p < 0.05, with respect to zero). Under the conditions imposed in the current study, ingesting the greater volume of the beverage lead to larger mean PV expansion.
- Description: C1
- Description: 2003001182
- Authors: Kay, Bartholomew , O'Brien, Brendan , Gill, Nicholas
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Sports Science and Medicine Vol. 4, no. 2 (2005), p. 179-184
- Full Text:
- Reviewed:
- Description: The effects of two volumes (1.5 L or 3.0 L) of commercially available electrolyte beverage (1.44 mM·L-1 Na+) taken during a 24-hour recovery period post-exercise, on plasma volume (PV) expansion 24-hours post-exercise were assessed. A simple random-order crossover research design was used. Subjects (n = 9 males: age 21 ± 4 years, body mass 80.0 ± 9.0 kg, peak incremental 60-second cycling power output 297 ± 45 W [means ± SD]) completed an identical exercise protocol conducted in hot ambient conditions (35°C, 50% relative humidity) on two occasions; separated by 7-days. On each occasion, subjects received a different volume of 24-hour fluid intake (commercial beverage) in random order. In each case, the fluid was taken in five equal aliquots over 24-hours. PV expansions 24-hours post-exercise were estimated from changes in haemoglobin and haematocrit. Dependent t-testing revealed no significant differences in PV expansions between trials, however a significant expansion with respect to zero was identified in the 3.0 L trial only. Specifically, PV expansions (%) were; 1.5 L trial: (mean ± SE) 2.3 ± 2.0 (not significant with respect to zero), 3.0 L trial: 5.0 ± 2.0 (p < 0.05, with respect to zero). Under the conditions imposed in the current study, ingesting the greater volume of the beverage lead to larger mean PV expansion.
- Description: C1
- Description: 2003001182
Six minute walk distance is greater when performed in a group than alone
- Grindrod, D., Paton, Carl, Knez, Wade, O'Brien, Brendan
- Authors: Grindrod, D. , Paton, Carl , Knez, Wade , O'Brien, Brendan
- Date: 2006
- Type: Text , Journal article
- Relation: British Journal of Sports Medicine Vol. 40, no. 10 (Oct 2006), p. 876-877
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- Description: Objective: To investigate whether the distance covered in the six minute walk test was affected by walking with a group of others in comparison with performing the test alone. Methods: Eight healthy men ( mean (SD) age 21.0 (0.9) years) and eight healthy women ( mean ( SD) age 20.8 (2.0) years) performed in random order two six minute walk tests either alone or in a group of four on two separate occasions one week apart. Results: Distance covered increased significantly from a mean of 653 ( 61) m in the individual male tests to 735 (79) m in the male group tests ( p< 0.05), and 616 ( 75) m in the individual female tests to 701 ( 54) m in the female group tests ( p< 0.01). The men increased the distance walked in six minutes by 12.5% and the women by 13.7% when they performed the test as a group. Conclusion: Performing the six minute walk test in a group facilitates its execution.
- Description: C1
- Description: 2003002117
- Authors: Grindrod, D. , Paton, Carl , Knez, Wade , O'Brien, Brendan
- Date: 2006
- Type: Text , Journal article
- Relation: British Journal of Sports Medicine Vol. 40, no. 10 (Oct 2006), p. 876-877
- Full Text:
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- Description: Objective: To investigate whether the distance covered in the six minute walk test was affected by walking with a group of others in comparison with performing the test alone. Methods: Eight healthy men ( mean (SD) age 21.0 (0.9) years) and eight healthy women ( mean ( SD) age 20.8 (2.0) years) performed in random order two six minute walk tests either alone or in a group of four on two separate occasions one week apart. Results: Distance covered increased significantly from a mean of 653 ( 61) m in the individual male tests to 735 (79) m in the male group tests ( p< 0.05), and 616 ( 75) m in the individual female tests to 701 ( 54) m in the female group tests ( p< 0.01). The men increased the distance walked in six minutes by 12.5% and the women by 13.7% when they performed the test as a group. Conclusion: Performing the six minute walk test in a group facilitates its execution.
- Description: C1
- Description: 2003002117
Telomere length maintenance and cardio-metabolic disease prevention through exercise training
- Denham, Joshua, O'Brien, Brendan, Charchar, Fadi
- Authors: Denham, Joshua , O'Brien, Brendan , Charchar, Fadi
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 46, no. 9 (2016), p. 1213-1237
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
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- Description: Telomeres are tandem repeat DNA sequences located at distal ends of chromosomes that protect against genomic DNA degradation and chromosomal instability. Excessive telomere shortening leads to cellular senescence and for this reason telomere length is a marker of biological age. Abnormally short telomeres may culminate in the manifestation of a number of cardio-metabolic diseases. Age-related cardio-metabolic diseases attributable to an inactive lifestyle, such as obesity, type 2 diabetes mellitus and cardiovascular disease, are associated with short leukocyte telomeres. Exercise training prevents and manages the symptoms of many cardio-metabolic diseases whilst concurrently maintaining telomere length. The positive relationship between exercise training, physical fitness and telomere length raises the possibility of a mediating role of telomeres in chronic disease prevention via exercise. Further elucidation of the underpinning molecular mechanisms of how exercise maintains telomere length should provide crucial information on how physical activity can be best structured to combat the chronic disease epidemic and improve the human health span. Here, we synthesise and discuss the current evidence on the impact of physical activity and cardiorespiratory fitness on telomere dynamics. We provide the molecular mechanisms with a known role in exercise-induced telomere length maintenance and highlight unexplored, alternative pathways ripe for future investigations.
- Authors: Denham, Joshua , O'Brien, Brendan , Charchar, Fadi
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 46, no. 9 (2016), p. 1213-1237
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
- Reviewed:
- Description: Telomeres are tandem repeat DNA sequences located at distal ends of chromosomes that protect against genomic DNA degradation and chromosomal instability. Excessive telomere shortening leads to cellular senescence and for this reason telomere length is a marker of biological age. Abnormally short telomeres may culminate in the manifestation of a number of cardio-metabolic diseases. Age-related cardio-metabolic diseases attributable to an inactive lifestyle, such as obesity, type 2 diabetes mellitus and cardiovascular disease, are associated with short leukocyte telomeres. Exercise training prevents and manages the symptoms of many cardio-metabolic diseases whilst concurrently maintaining telomere length. The positive relationship between exercise training, physical fitness and telomere length raises the possibility of a mediating role of telomeres in chronic disease prevention via exercise. Further elucidation of the underpinning molecular mechanisms of how exercise maintains telomere length should provide crucial information on how physical activity can be best structured to combat the chronic disease epidemic and improve the human health span. Here, we synthesise and discuss the current evidence on the impact of physical activity and cardiorespiratory fitness on telomere dynamics. We provide the molecular mechanisms with a known role in exercise-induced telomere length maintenance and highlight unexplored, alternative pathways ripe for future investigations.
The effects of interval-exercise duration and intensity on oxygen consumption during treadmill running
- O'Brien, Brendan, Wibskov, Jim, Knez, Wade, Paton, Carl, Harvey, Jack
- Authors: O'Brien, Brendan , Wibskov, Jim , Knez, Wade , Paton, Carl , Harvey, Jack
- Date: 2008
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 11, no. 3 (2008), p. 287-290
- Full Text:
- Reviewed:
- Description: The magnitude of improvement in peak oxygen uptake (over(V, ̇)
- Description: C1
- Authors: O'Brien, Brendan , Wibskov, Jim , Knez, Wade , Paton, Carl , Harvey, Jack
- Date: 2008
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 11, no. 3 (2008), p. 287-290
- Full Text:
- Reviewed:
- Description: The magnitude of improvement in peak oxygen uptake (over(V, ̇)
- Description: C1
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