Accelerometer load as a measure of activity profile in different standards of netball match play
- Cormack, Stuart, Smith, Renee, Mooney, Mitchell, Young, Warren, O'Brien, Brendan
- Authors: Cormack, Stuart , Smith, Renee , Mooney, Mitchell , Young, Warren , O'Brien, Brendan
- Date: 2014
- Type: Text , Journal article
- Relation: International Journal of Sports Physiology and Performance Vol. 9, no. 2 (2014), p. 283-291
- Full Text: false
- Reviewed:
- Description: To determine differences in load/min (AU) between standards of netball match play., Methods: Load/ min (AU) representing accumulated accelerations measured by triaxial accelerometers was recorded during matches of 2 higher- and 2 lower-standard teams (N = 32 players). Differences in load/min (AU) were compared within and between standards for playing position and periods of play. Differences were considered meaningful if there was >75% likelihood of exceeding a small (0.2) effect size., Results: Mean (± SD) full-match load/min (AU) for the higher and lower standards were 9.96 ± 2.50 and 6.88 ± 1.88, respectively (100% likely lower). The higher standard had greater (mean 97% likely) load/min (AU) values in each position. The difference between 1st and 2nd halves' load/min (AU) was unclear at the higher standard, while lower-grade centers had a lower (-7.7% ± 10.8%, 81% likely) load/min (AU) in the 2nd half and in all quarters compared with the 1st. There was little intrastandard variation in individual vector contributions to load/min (AU); however, higher-standard players accumulated a greater proportion of the total in the vertical plane (mean 93% likely)., Conclusions: Higher-standard players produced greater load/min (AU) than their lower-standard counterparts in all positions. Playing standard influenced the pattern of load/min (AU) accumulation across a match, and individual vector analysis suggests that different-standard players have dissimilar movement characteristics. Load/min (AU) appears to be a useful method for assessing activity profile in netball. © 2014 Human Kinetics, Inc.
Acute effect of exercise on kicking accuracy in elite Australian football players
- Young, Warren, Gulli, Rachael, Rath, David, Russell, Andrew, O'Brien, Brendan, Harvey, Jack
- Authors: Young, Warren , Gulli, Rachael , Rath, David , Russell, Andrew , O'Brien, Brendan , Harvey, Jack
- Date: 2010
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 13, no. 1 (2010), p. 85-89
- Full Text: false
- Reviewed:
- Description: Kicking accuracy (KA) is an important skill in Australian football but the potential influence of exercise on this skill has not been previously investigated. The purpose of this study was to determine if a 2× 2 min time trial running protocol influenced short KA in elite Australian football. Another aim was to identify if endurance, playing experience and position were related to any exercise-induced KA changes. Twenty-seven professional footballers performed a KA test by kicking at a bullseye on a target projected onto a screen. The mean error from the centre of the target was the KA score. The players were assessed on the KA test, and then performed a 2× 2 min time trial with a 3-min recovery between runs. The total distance covered was used as a measure of endurance fitness, and the test also served as an exercise bout designed to impose some physiological stress. Immediately following this test, the players walked into the laboratory and performed the KA test again. A paired t-test revealed that the whole group achieved a non-significant 2.7% improvement in KA. Players were divided into two distinct groups based on endurance (2× 2 min results), playing experience and position (midfielders and forwards/backs). Analysis of covariance showed that after the exercise bout, the fitter group had significantly better KA (p = 0.010) than the less fit group, and the more experienced players were 16% more accurate than the less experienced group (p = 0.055). The midfielders were 8.2% better than the forwards/backs in KA (p = 0.32). It was suggested that greater endurance and playing experience may facilitate KA under moderate physiological stress. © 2008 Sports Medicine Australia.
- Description: 2003008125
Acute exercise leads to regulation of Telomere-Associated genes and MicroRNA expression in immune Cells
- Chilton, Warrick, Marques, Francine, West, Jenny, Kannourakis, George, Berzins, Stuart, O'Brien, Brendan, Charchar, Fadi
- Authors: Chilton, Warrick , Marques, Francine , West, Jenny , Kannourakis, George , Berzins, Stuart , O'Brien, Brendan , Charchar, Fadi
- Date: 2014
- Type: Text , Journal article
- Relation: PloS One Vol. 9, no. 4 (2014), p. e92088
- Full Text:
- Reviewed:
- Description: Telomeres are specialized nucleoprotein structures that protect chromosomal ends from degradation. These structures progressively shorten during cellular division and can signal replicative senescence below a critical length. Telomere length is predominantly maintained by the enzyme telomerase. Significant decreases in telomere length and telomerase activity are associated with a host of chronic diseases; conversely their maintenance underpins the optimal function of the adaptive immune system. Habitual physical activity is associated with longer leukocyte telomere length; however, the precise mechanisms are unclear. Potential hypotheses include regulation of telomeric gene transcription and/or microRNAs (miRNAs). We investigated the acute exercise-induced response of telomeric genes and miRNAs in twenty-two healthy males (mean age = 24.1±1.55 years). Participants undertook 30 minutes of treadmill running at 80% of peak oxygen uptake. Blood samples were taken before exercise, immediately post-exercise and 60 minutes post-exercise. Total RNA from white blood cells was submitted to miRNA arrays and telomere extension mRNA array. Results were individually validated in white blood cells and sorted T cell lymphocyte subsets using quantitative real-time PCR (qPCR). Telomerase reverse transcriptase (TERT) mRNA (P = 0.001) and sirtuin-6 (SIRT6) (P<0.05) mRNA expression were upregulated in white blood cells after exercise. Fifty-six miRNAs were also differentially regulated post-exercise (FDR <0.05). In silico analysis identified four miRNAs (miR-186, miR-181, miR-15a and miR-96) that potentially targeted telomeric gene mRNA. The four miRNAs exhibited significant upregulation 60 minutes post-exercise (P<0.001). Telomeric repeat binding factor 2, interacting protein (TERF2IP) was identified as a potential binding target for miR-186 and miR-96 and demonstrated concomitant downregulation (P<0.01) at the corresponding time point. Intense cardiorespiratory exercise was sufficient to differentially regulate key telomeric genes and miRNAs in white blood cells. These results may provide a mechanistic insight into telomere homeostasis and improved immune function and physical health. Funding NHMRC
- Authors: Chilton, Warrick , Marques, Francine , West, Jenny , Kannourakis, George , Berzins, Stuart , O'Brien, Brendan , Charchar, Fadi
- Date: 2014
- Type: Text , Journal article
- Relation: PloS One Vol. 9, no. 4 (2014), p. e92088
- Full Text:
- Reviewed:
- Description: Telomeres are specialized nucleoprotein structures that protect chromosomal ends from degradation. These structures progressively shorten during cellular division and can signal replicative senescence below a critical length. Telomere length is predominantly maintained by the enzyme telomerase. Significant decreases in telomere length and telomerase activity are associated with a host of chronic diseases; conversely their maintenance underpins the optimal function of the adaptive immune system. Habitual physical activity is associated with longer leukocyte telomere length; however, the precise mechanisms are unclear. Potential hypotheses include regulation of telomeric gene transcription and/or microRNAs (miRNAs). We investigated the acute exercise-induced response of telomeric genes and miRNAs in twenty-two healthy males (mean age = 24.1±1.55 years). Participants undertook 30 minutes of treadmill running at 80% of peak oxygen uptake. Blood samples were taken before exercise, immediately post-exercise and 60 minutes post-exercise. Total RNA from white blood cells was submitted to miRNA arrays and telomere extension mRNA array. Results were individually validated in white blood cells and sorted T cell lymphocyte subsets using quantitative real-time PCR (qPCR). Telomerase reverse transcriptase (TERT) mRNA (P = 0.001) and sirtuin-6 (SIRT6) (P<0.05) mRNA expression were upregulated in white blood cells after exercise. Fifty-six miRNAs were also differentially regulated post-exercise (FDR <0.05). In silico analysis identified four miRNAs (miR-186, miR-181, miR-15a and miR-96) that potentially targeted telomeric gene mRNA. The four miRNAs exhibited significant upregulation 60 minutes post-exercise (P<0.001). Telomeric repeat binding factor 2, interacting protein (TERF2IP) was identified as a potential binding target for miR-186 and miR-96 and demonstrated concomitant downregulation (P<0.01) at the corresponding time point. Intense cardiorespiratory exercise was sufficient to differentially regulate key telomeric genes and miRNAs in white blood cells. These results may provide a mechanistic insight into telomere homeostasis and improved immune function and physical health. Funding NHMRC
Analysis of a reactive agility test using a live tester
- Willey, Benjamin, Young, Warren, O'Brien, Brendan
- Authors: Willey, Benjamin , Young, Warren , O'Brien, Brendan
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Australian Strength and Conditioning
- Relation: Vol. 27, no. 2 (2019), p. 19-31
- Full Text: false
- Reviewed:
- Description: The utility of a reactive agility test using a live tester (LRAT) was investigated by assessing the variability and reliability of the tester’s movements. Of interest was how the tester’s actions influenced the agility measure of total test time (Ttt). Thirty-one (N=31) semi-elite Australian Rules football players were used to investigate the impact of tester time (TT) variability. A single subject was employed as the test presenter. The LRAT was presented to the playing group on two occasions (test 1 and test 2) separated by a period of 47 days. The impact of the TT on the subject’s agility was investigated for test 1 only. The TT displayed between subject variability within a session. The TT was initiated by the testers’ forward movement and ceased the instant the tester planted his outside foot to change direction. This was represented by the coefficient of variation, and the range expressed as a percentage of the mean. These were 4.8% and 25.6%, respectively. To understand the impact of this, subjects were ranked from fastest to slowest for Ttt, before being re-ranked after the TT was removed. This resulted in 22 out of the 31 subjects changing rank. The test-retest for the TT revealed a very large and significant decrease in time (p = .0001). This was accompanied by an intraclass correlation coefficient (ICC) of -0.04. Thus, the TT failed to provide a stable measure. Based on these findings it is recommended that measures such as agility time (AT), i.e. Ttt minus the TT, be used instead of Ttt. Further, isolating measures of perception and decision-making abilities (PDM) from the physical qualities is recommended to enhance agility inferences.
- Larkin, Paul, O'Brien, Brendan, Mesagno, Christopher, Berry, Jason, Harvey, Jack, Spittle, Michael
- Authors: Larkin, Paul , O'Brien, Brendan , Mesagno, Christopher , Berry, Jason , Harvey, Jack , Spittle, Michael
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of Sports Sciences Vol. 32, no. 15 (2014), p. 1446-1453
- Full Text: false
- Reviewed:
- Description: The aim of this study is to investigate the effects of in-game physical exertion on decision-making performance of Australian football umpires. Fifteen Australian football umpires (Mage = 36, s = 13.5 years; Mgames umpired = 235.2, s = 151.3) volunteered to participate in the study. During five competitive Australian football pre-season games, measures of in-game physical exertion (blood lactate levels, global positioning system [GPS]) and decision-making performance (video-based test) were obtained. There were no significant correlations between physical exertion in a particular quarter and decision-making performance in either the same quarter or any other quarter. Video-based decision-making performance was effected by time in game χ2(3) = 24.24, P = 0.001, with Quarter 4 performance significantly better than both Quarter 2 and Quarter 3. In-game physical exertion (blood lactate) significantly decreased over the course of the game χ2(3) = 11.58, P = 0.009. Results indicate no definable link between in-game physical exertion and decision-making performance. It is, however, presumed that decision-making performance may be affected by the time or context of the game. Future research is warranted to explore the relationship between physical exertion and decision-making performance to potentially inform Australian football umpire training programmes that replicate in-game physical and decision-making demands.
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
- 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
- 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
Changes in the leukocyte methylome and its effect on cardiovascular-related genes after exercise
- Denham, Joshua, O'Brien, Brendan, Marques, Francine, Charchar, Fadi
- Authors: Denham, Joshua , O'Brien, Brendan , Marques, Francine , Charchar, Fadi
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Applied Physiology Vol. 118, no. 4 (2015), p. 475-488
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text: false
- Reviewed:
- Description: Physical exercise has proven cardiovascular benefits, yet there is no clear understanding of the related molecular mechanisms leading to this. Here we determined the beneficial epigenetic effects of exercise after sprint interval training, a form of exercise known to improve cardiometabolic health. We quantified genome-wide leukocyte DNA methylation of 12 healthy young (18-24 yr) men before and after 4 wk (thrice weekly) of sprint interval training using the 450K BeadChip (Illumina) and validated gene expression changes in an extra seven subjects. Exercise increased subjects' cardiorespiratory fitness and maximal running performance, and decreased low-density lipoprotein cholesterol concentration in conjunction with genome-wide DNA methylation changes. Notably, many CpG island and gene promoter regions were demethylated after exercise, indicating increased genome-wide transcriptional changes. Among genes with DNA methylation changes, epidermal growth factor (EGF), a ligand of the epidermal growth factor receptor known to be involved in cardiovascular disease, was demethylated and showed decreased mRNA expression. Additionally, we found that in microRNAs miR-21 and miR-210, gene DNA methylation was altered by exercise causing a cascade effect on the expression of the mature microRNA involved in cardiovascular function. Our findings demonstrate that exercise alters DNA methylation in circulating blood cells in microRNA and protein-coding genes associated with cardiovascular physiology. Copyright © 2015 the American Physiological Society
Consecutive bouts of diverse contractile activity alter acute responses in human skeletal muscle
- Coffey, V. G., Pilegaard, H., Garnham, A. P., O'Brien, Brendan, Hawley, J. A.
- Authors: Coffey, V. G. , Pilegaard, H. , Garnham, A. P. , O'Brien, Brendan , Hawley, J. A.
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Applied Physiology Vol. 106, no. 4 (2009), p. 1187-1197
- Full Text:
- Reviewed:
- Description: We examined acute molecular responses in skeletal muscle to divergent exercise stimuli by combining consecutive bouts of resistance and endurance exercise. Eight men [22.9 ± 6.3 yr, body mass of 73.2 ± 4.5 kg, peak O2 uptake (V̇O2peak) of 54.0 ± 5.7 ml·kg-1·min-1] were randomly assigned to complete trials consisting of either resistance exercise (8 x 5 leg extension, 80% 1 repetition maximum) followed by a bout of endurance exercise (30 min cycling, 70% V̇O2peak) or vice versa. Muscle biopsies were obtained from the vastus lateralis at rest, 15 min after each exercise bout, and after 3 h of passive recovery to determine early signaling and mRNA responses. Phosphorylation of Akt and Akt1Ser473 were elevated 15 min after resistance exercise compared with cycling, with the greatest increase observed when resistance exercise followed cycling (∼55%; P < 0.01). TSC2-mTOR-S6 kinase phosphorylation 15 min after each bout of exercise was similar regardless of the exercise mode. The cumulative effect of combined exercise resulted in disparate mRNA responses. IGF-I mRNA content was reduced when cycling preceded resistance exercise (-42%), whereas muscle ring finger mRNA was elevated when cycling was undertaken after resistance exercise (∼52%; P < 0.05). The hexokinase II mRNA level was higher after resistance cycling (∼45%; P < 0.05) than after cycling-resistance exercise, whereas modest increases in peroxisome proliferator-activated receptor gamma coactivator-1α mRNA did not reveal an order effect. We conclude that acute responses to diverse bouts of contractile activity are modified by the exercise order. Moreover, undertaking divergent exercise in close proximity influences the acute molecular profile and likely exacerbates acute "interference." Copyright © 2009 the American Physiological Society.
- Description: 2003008129
- Authors: Coffey, V. G. , Pilegaard, H. , Garnham, A. P. , O'Brien, Brendan , Hawley, J. A.
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Applied Physiology Vol. 106, no. 4 (2009), p. 1187-1197
- Full Text:
- Reviewed:
- Description: We examined acute molecular responses in skeletal muscle to divergent exercise stimuli by combining consecutive bouts of resistance and endurance exercise. Eight men [22.9 ± 6.3 yr, body mass of 73.2 ± 4.5 kg, peak O2 uptake (V̇O2peak) of 54.0 ± 5.7 ml·kg-1·min-1] were randomly assigned to complete trials consisting of either resistance exercise (8 x 5 leg extension, 80% 1 repetition maximum) followed by a bout of endurance exercise (30 min cycling, 70% V̇O2peak) or vice versa. Muscle biopsies were obtained from the vastus lateralis at rest, 15 min after each exercise bout, and after 3 h of passive recovery to determine early signaling and mRNA responses. Phosphorylation of Akt and Akt1Ser473 were elevated 15 min after resistance exercise compared with cycling, with the greatest increase observed when resistance exercise followed cycling (∼55%; P < 0.01). TSC2-mTOR-S6 kinase phosphorylation 15 min after each bout of exercise was similar regardless of the exercise mode. The cumulative effect of combined exercise resulted in disparate mRNA responses. IGF-I mRNA content was reduced when cycling preceded resistance exercise (-42%), whereas muscle ring finger mRNA was elevated when cycling was undertaken after resistance exercise (∼52%; P < 0.05). The hexokinase II mRNA level was higher after resistance cycling (∼45%; P < 0.05) than after cycling-resistance exercise, whereas modest increases in peroxisome proliferator-activated receptor gamma coactivator-1α mRNA did not reveal an order effect. We conclude that acute responses to diverse bouts of contractile activity are modified by the exercise order. Moreover, undertaking divergent exercise in close proximity influences the acute molecular profile and likely exacerbates acute "interference." Copyright © 2009 the American Physiological Society.
- Description: 2003008129
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
- Full Text:
- Reviewed:
- 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
- Full Text:
- Reviewed:
- 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
Effects of a seven day overload-period of high-intensity training on performance and physiology of competitive cyclists
- Clark, Bradley, Costa, Vitor, O'Brien, Brendan, Guglielmo, Luiz, Paton, Carl
- Authors: Clark, Bradley , Costa, Vitor , O'Brien, Brendan , Guglielmo, Luiz , Paton, Carl
- Date: 2014
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 9, no. 12 (2014), p. art no. e115308
- Full Text:
- Reviewed:
- Description: Abstract Objectives Competitive endurance athletes commonly undertake periods of overload training in the weeks prior to major competitions. This investigation examined the effects of two seven-day high-intensity overload training regimes (HIT) on performance and physiological characteristics of competitive cyclists. Design The study was a matched groups, controlled trial. Methods Twenty-eight male cyclists (mean ± SD, Age: 33±10 years, Mass 74±7 kg, VO2 peak 4.7±0.5 L·min−1) were assigned to a control group or one of two training groups for seven consecutive days of HIT. Before and after training cyclists completed an ergometer based incremental exercise test and a 20-km time-trial. The HIT sessions were ~120 minutes in duration and consisted of matched volumes of 5, 10 and 20 second (short) or 15, 30 and 45 second (long) maximal intensity efforts. Results Both the short and long HIT regimes led to significant (p<0.05) gains in time trial performance compared to the control group. Relative to the control group, the mean changes (±90% confidence limits) in time-trial power were 8.2%±3.8% and 10.4%±4.3% for the short and long HIT regimes respectively; corresponding increases in peak power in the incremental test were 5.5%±2.7% and 9.5%±2.5%. Both HIT (short vs long) interventions led to non-significant (p>0.05) increases (mean ± SD) in VO2 peak (2.3%±4.7% vs 3.5%±6.2%), lactate threshold power (3.6%±3.5% vs 2.9%±5.3%) and gross efficiency (3.2%±2.4% vs 5.1%±3.9%) with only small differences between HIT regimes. Conclusions Seven days of overload HIT induces substantial enhancements in time-trial performance despite non-significant increases in physiological measures with competitive cyclists
- Authors: Clark, Bradley , Costa, Vitor , O'Brien, Brendan , Guglielmo, Luiz , Paton, Carl
- Date: 2014
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 9, no. 12 (2014), p. art no. e115308
- Full Text:
- Reviewed:
- Description: Abstract Objectives Competitive endurance athletes commonly undertake periods of overload training in the weeks prior to major competitions. This investigation examined the effects of two seven-day high-intensity overload training regimes (HIT) on performance and physiological characteristics of competitive cyclists. Design The study was a matched groups, controlled trial. Methods Twenty-eight male cyclists (mean ± SD, Age: 33±10 years, Mass 74±7 kg, VO2 peak 4.7±0.5 L·min−1) were assigned to a control group or one of two training groups for seven consecutive days of HIT. Before and after training cyclists completed an ergometer based incremental exercise test and a 20-km time-trial. The HIT sessions were ~120 minutes in duration and consisted of matched volumes of 5, 10 and 20 second (short) or 15, 30 and 45 second (long) maximal intensity efforts. Results Both the short and long HIT regimes led to significant (p<0.05) gains in time trial performance compared to the control group. Relative to the control group, the mean changes (±90% confidence limits) in time-trial power were 8.2%±3.8% and 10.4%±4.3% for the short and long HIT regimes respectively; corresponding increases in peak power in the incremental test were 5.5%±2.7% and 9.5%±2.5%. Both HIT (short vs long) interventions led to non-significant (p>0.05) increases (mean ± SD) in VO2 peak (2.3%±4.7% vs 3.5%±6.2%), lactate threshold power (3.6%±3.5% vs 2.9%±5.3%) and gross efficiency (3.2%±2.4% vs 5.1%±3.9%) with only small differences between HIT regimes. Conclusions Seven days of overload HIT induces substantial enhancements in time-trial performance despite non-significant increases in physiological measures with competitive cyclists
Epigenetic changes in leukocytes after 8 weeks of resistance exercise training
- Denham, Joshua, Marques, Francine, Bruns, Emma, O'Brien, Brendan, Charchar, Fadi
- Authors: Denham, Joshua , Marques, Francine , Bruns, Emma , O'Brien, Brendan , Charchar, Fadi
- Date: 2016
- Type: Text , Journal article
- Relation: European Journal of Applied Physiology Vol. 116, no. 6 (2016), p. 1245-1253
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text: false
- Reviewed:
- Description: PURPOSE: Regular engagement in resistance exercise training elicits many health benefits including improvement to muscular strength, hypertrophy and insulin sensitivity, though the underpinning molecular mechanisms are poorly understood. The purpose of this study was to determine the influence 8 weeks of resistance exercise training has on leukocyte genome-wide DNA methylation and gene expression in healthy young men. METHODS: Eight young (21.1 +/- 2.2 years) men completed one repetition maximum (1RM) testing before completing 8 weeks of supervised, thrice-weekly resistance exercise training comprising three sets of 8-12 repetitions with a load equivalent to 80 % of 1RM. Blood samples were collected at rest before and after the 8-week training intervention. Genome-wide DNA methylation and gene expression were assessed on isolated leukocyte DNA and RNA using the 450K BeadChip and HumanHT-12 v4 Expression BeadChip (Illumina), respectively. RESULTS: Resistance exercise training significantly improved upper and lower body strength concurrently with diverse genome-wide DNA methylation and gene expression changes (p = 0. 01). DNA methylation changes occurred at multiple regions throughout the genome in context with genes and CpG islands, and in genes relating to axon guidance, diabetes and immune pathways. There were multiple genes with increased expression that were enriched for RNA processing and developmental proteins. Growth factor genes-GHRH and FGF1-showed differential methylation and mRNA expression changes after resistance training. CONCLUSIONS: Our findings indicate that resistance exercise training improves muscular strength and is associated with reprogramming of the leukocyte DNA methylome and transcriptome.
Exercise : Putting action into our epigenome
- Denham, Joshua, Marques, Francine, O'Brien, Brendan, Charchar, Fadi
- Authors: Denham, Joshua , Marques, Francine , O'Brien, Brendan , Charchar, Fadi
- Date: 2014
- Type: Text , Journal article
- Relation: Sports Medicine Vol. 44, no. 2 (2014), p. 189-209
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
- Reviewed:
- Description: Most human phenotypes are influenced by a combination of genomic and environmental factors. Engaging in regular physical exercise prevents many chronic diseases, decreases mortality risk and increases longevity. However, the mechanisms involved are poorly understood. The modulating effect of physical (aerobic and resistance) exercise on gene expression has been known for some time now and has provided us with an understanding of the biological responses to physical exercise. Emerging research data suggest that epigenetic modifications are extremely important for both development and disease in humans. In the current review, we summarise findings on the effect of exercise on epigenetic modifications and their effects on gene expression. Current research data suggest epigenetic modifications (DNA methylation and histone acetylation) and microRNAs (miRNAs) are responsive to acute aerobic and resistance exercise in brain, blood, skeletal and cardiac muscle, adipose tissue and even buccal cells. Six months of aerobic exercise alters whole-genome DNA methylation in skeletal muscle and adipose tissue and directly influences lipogenesis. Some miRNAs are related to maximal oxygen consumption (VO 2max) and VO2max trainability, and are differentially expressed amongst individuals with high and low VO2max. Remarkably, miRNA expression profiles discriminate between low and high responders to resistance exercise (miR-378, -26a, -29a and -451) and correlate to gains in lean body mass (miR-378). The emerging field of exercise epigenomics is expected to prosper and additional studies may elucidate the clinical relevance of miRNAs and epigenetic modifications, and delineate mechanisms by which exercise confers a healthier phenotype and improves performance. © 2013 Springer International Publishing Switzerland. Funded by NHMRC; National Health and Medical Research Council
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
- Full Text:
- Reviewed:
- 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
- Full Text:
- Reviewed:
- 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.
Genome-wide sperm DNA methylation changes after 3 months of exercise training in humans
- Denham, Joshua, O'Brien, Brendan, Harvey, Jack, Charchar, Fadi
- Authors: Denham, Joshua , O'Brien, Brendan , Harvey, Jack , Charchar, Fadi
- Date: 2015
- Type: Text , Journal article
- Relation: Epigenomics Vol. 7, no. 5 (2015), p. 717-731
- Full Text:
- Reviewed:
- Description: Aim: DNA methylation programs gene expression and is involved in numerous biological processes. Accumulating evidence supports transgenerational inheritance of DNA methylation changes in mammals via germ cells. Our aim was to determine the effect of exercise on sperm DNA methylation. Materials & methods: Twenty-four men were recruited and assigned to an exercise intervention or control group. Clinical parameters were measured and sperm samples were donated by subjects before and after the 3-month time-period. Mature sperm global and genome-wide DNA methylation was assessed using an ELISA assay and the 450K BeadChip (Illumina). Results: Global and genome-wide sperm DNA methylation was altered after 3 months of exercise training. DNA methylation changes occurred in genes related to numerous diseases such as schizophrenia and Parkinson's disease. Conclusions: Our study provides the first evidence showing exercise training reprograms the sperm methylome. Whether these DNA methylation changes are inherited to future generations warrants attention.
- Authors: Denham, Joshua , O'Brien, Brendan , Harvey, Jack , Charchar, Fadi
- Date: 2015
- Type: Text , Journal article
- Relation: Epigenomics Vol. 7, no. 5 (2015), p. 717-731
- Full Text:
- Reviewed:
- Description: Aim: DNA methylation programs gene expression and is involved in numerous biological processes. Accumulating evidence supports transgenerational inheritance of DNA methylation changes in mammals via germ cells. Our aim was to determine the effect of exercise on sperm DNA methylation. Materials & methods: Twenty-four men were recruited and assigned to an exercise intervention or control group. Clinical parameters were measured and sperm samples were donated by subjects before and after the 3-month time-period. Mature sperm global and genome-wide DNA methylation was assessed using an ELISA assay and the 450K BeadChip (Illumina). Results: Global and genome-wide sperm DNA methylation was altered after 3 months of exercise training. DNA methylation changes occurred in genes related to numerous diseases such as schizophrenia and Parkinson's disease. Conclusions: Our study provides the first evidence showing exercise training reprograms the sperm methylome. Whether these DNA methylation changes are inherited to future generations warrants attention.
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
- 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
- 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
Impact of neuromuscular fatigue on match exercise intensity and performance in elite Australian football
- Mooney, Mitchell, Cormack, Stuart, O'Brien, Brendan, Morgan, William, McGuigan, Mike
- Authors: Mooney, Mitchell , Cormack, Stuart , O'Brien, Brendan , Morgan, William , McGuigan, Mike
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 27, no. 1 (2013), p. 166-173
- Full Text:
- Reviewed:
- Description: Mooney, MG, Cormack, S, O'Brien, BJ, Morgan, WM, and McGuigan, M. Impact of neuromuscular fatigue on match exercise intensity and performance in elite Australian football. J Strength Cond Res 27(1): 166-173, 2013: This study aimed to quantify the influence of neuromuscular fatigue (NMF) via flight time to contraction time ratio (FT:CT) obtained from a countermovement jump (CMJ) on the relationships between yo-yo intermittent recovery (level 2) test (yo-yo IR2), match exercise intensity (high-intensity running [HIR] m·min-1 and Load·min-1) and Australian football (AF) performance. Thirty-seven data sets were collected from 17 different players across 22 elite AF matches. Each data set comprised an athlete's yo-yo IR2 score before the start of the season, match exercise intensity via global positioning system and on-field performance rated by coaches' votes and number of ball disposals. Each data set was categorized as normal (>92% baseline FT:CT, n = 20) or fatigued (<92% baseline FT:CT, n = 17) from a single CMJ performed 96 hours after the previous match. Moderation-mediation analysis was completed with yo-yo IR2 (independent variable), match exercise intensity (mediator), and AF performance (dependent variable) with NMF status as the conditional variable. Isolated interactions between variables were analyzed by Pearson's correlation and effect size statistics. The Yo-yo IR2 score showed an indirect influence on the number of ball disposals via HIR m·min-1 regardless of NMF status (normal FT:CT indirect effect = 0.019, p < 0.1, reduced FT:CT indirect effect = 0.022, p < 0.1). However, the yo-yo IR2 score only influenced coaches' votes via Load·min-1 in the nonfatigued state (normal: FT:CT indirect effect = 0.007, p <0.1, reduced: FT:CT indirect effect = -0.001, p > 0.1). In isolation, NMF status also reduces relationships between yo-yo IR2 and load·min-1, yo-yo IR2 and coaches votes, Load·min-1 and coaches' votes ([DELTA]r > 0.1). Routinely testing yo-yo IR2 capacity, NMF via FT:CT and monitoring Load·min-1 in conjunction with HIR m·min-1 as exercise intensity measures in elite AF is recommended. © 2013 National Strength and Conditioning Association.
- Description: 2003010830
- Authors: Mooney, Mitchell , Cormack, Stuart , O'Brien, Brendan , Morgan, William , McGuigan, Mike
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 27, no. 1 (2013), p. 166-173
- Full Text:
- Reviewed:
- Description: Mooney, MG, Cormack, S, O'Brien, BJ, Morgan, WM, and McGuigan, M. Impact of neuromuscular fatigue on match exercise intensity and performance in elite Australian football. J Strength Cond Res 27(1): 166-173, 2013: This study aimed to quantify the influence of neuromuscular fatigue (NMF) via flight time to contraction time ratio (FT:CT) obtained from a countermovement jump (CMJ) on the relationships between yo-yo intermittent recovery (level 2) test (yo-yo IR2), match exercise intensity (high-intensity running [HIR] m·min-1 and Load·min-1) and Australian football (AF) performance. Thirty-seven data sets were collected from 17 different players across 22 elite AF matches. Each data set comprised an athlete's yo-yo IR2 score before the start of the season, match exercise intensity via global positioning system and on-field performance rated by coaches' votes and number of ball disposals. Each data set was categorized as normal (>92% baseline FT:CT, n = 20) or fatigued (<92% baseline FT:CT, n = 17) from a single CMJ performed 96 hours after the previous match. Moderation-mediation analysis was completed with yo-yo IR2 (independent variable), match exercise intensity (mediator), and AF performance (dependent variable) with NMF status as the conditional variable. Isolated interactions between variables were analyzed by Pearson's correlation and effect size statistics. The Yo-yo IR2 score showed an indirect influence on the number of ball disposals via HIR m·min-1 regardless of NMF status (normal FT:CT indirect effect = 0.019, p < 0.1, reduced FT:CT indirect effect = 0.022, p < 0.1). However, the yo-yo IR2 score only influenced coaches' votes via Load·min-1 in the nonfatigued state (normal: FT:CT indirect effect = 0.007, p <0.1, reduced: FT:CT indirect effect = -0.001, p > 0.1). In isolation, NMF status also reduces relationships between yo-yo IR2 and load·min-1, yo-yo IR2 and coaches votes, Load·min-1 and coaches' votes ([DELTA]r > 0.1). Routinely testing yo-yo IR2 capacity, NMF via FT:CT and monitoring Load·min-1 in conjunction with HIR m·min-1 as exercise intensity measures in elite AF is recommended. © 2013 National Strength and Conditioning Association.
- Description: 2003010830
- Mooney, Mitchell, Cormack, Stuart, O'Brien, Brendan, Morgan, William, McGuigan, Mike
- Authors: Mooney, Mitchell , Cormack, Stuart , O'Brien, Brendan , Morgan, William , McGuigan, Mike
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 27, no. 1 (2013), p. 166-173
- Full Text: false
- Reviewed:
- Description: This study aimed to quantify the influence of neuromuscular fatigue (NMF) via flight time to contraction time ratio (FT:CT) obtained from a countermovement jump (CMJ) on the relationships between yo-yo intermittent recovery (level 2) test (yo-yo IR2), match exercise intensity (high-intensity running [HIR] m.min(-1) and Load.min(-1)) and Australian football (AF) performance. Thirty-seven data sets were collected from 17 different players across 22 elite AF matches. Each data set comprised an athlete's yo-yo IR2 score before the start of the season, match exercise intensity via global positioning system and on-field performance rated by coaches' votes and number of ball disposals. Each data set was categorized as normal (>92% baseline FT:CT, n = 20) or fatigued (<92% baseline FT:CT, n = 17) from a single CMJ performed 96 hours after the previous match. Moderation-mediation analysis was completed with yo-yo IR2 (independent variable), match exercise intensity (mediator), and AF performance (dependent variable) with NMF status as the conditional variable. Isolated interactions between variables were analyzed by Pearson's correlation and effect size statistics. The Yo-yo IR2 score showed an indirect influence on the number of ball disposals via HIR m.min(-1) regardless of NMF status (normal FT:CT indirect effect = 0.019, p < 0.1, reduced FT:CT indirect effect = 0.022, p < 0.1). However, the yo-yo IR2 score only influenced coaches' votes via Load.min(-1) in the nonfatigued state (normal: FT:CT indirect effect = 0.007, p <0.1, reduced: FT:CT indirect effect = -0.001, p > 0.1). In isolation, NMF status also reduces relationships between yo-yo IR2 and load.min(-1), yo-yo IR2 and coaches votes, Load.min(-1) and coaches' votes (Deltar > 0.1). Routinely testing yo-yo IR2 capacity, NMF via FT:CT and monitoring Load.min(-1) in conjunction with HIR m.min(-1) as exercise intensity measures in elite AF is recommended.
Increased expression of telomere-regulating genes in endurance athletes with long leukocyte telomeres
- Denham, Joshua, O'Brien, Brendan, Prestes, Priscilla, Brown, Nicholas, Charchar, Fadi
- Authors: Denham, Joshua , O'Brien, Brendan , Prestes, Priscilla , Brown, Nicholas , Charchar, Fadi
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Applied Physiology Vol. 120, no. 2 (2015), p. 148-158
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
- Reviewed:
- Description: Leukocyte telomeres shorten with age, and excessive shortening is associated with age-related cardiometabolic diseases. Exercise training may prevent disease through telomere length maintenance although the optimal amount of exercise that attenuates telomere attrition is unknown. Furthermore, the underlying molecular mechanisms responsible for the enhanced telomere maintenance observed in endurance athletes is poorly understood. We quantified the leukocyte telomere length and analyzed the expression of telomere-regulating genes in endurance athletes and healthy controls (both n = 61), using quantitative PCR. We found endurance athletes have significantly longer (7.1%, 208-416 nt) leukocyte telomeres and upregulated TERT (2.0-fold) and TPP1 (1.3-fold) mRNA expression compared with controls in age-adjusted analysis. The telomere length and telomere-regulating gene expression differences were no longer statistically significant after adjustment for resting heart rate and relative (V) over dotO(2 max) (all P > 0.05). Resting heart rate emerged as an independent predictor of leukocyte telomere length and TERT and TPP1 mRNA expression in stepwise regression models. To gauge whether volume of exercise was associated with leukocyte telomere length, we divided subjects into running and cycling tertiles (distance covered per week) and found individuals in the middle and highest tertiles had longer telomeres than individuals in the lowest tertile. These data emphasize the importance of cardiorespiratory fitness and exercise training in the prevention of biological aging. They also support the concept that moderate amounts of exercise training protects against biological aging, while higher amounts may not elicit additional benefits.
- Authors: Denham, Joshua , O'Brien, Brendan , Prestes, Priscilla , Brown, Nicholas , Charchar, Fadi
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Applied Physiology Vol. 120, no. 2 (2015), p. 148-158
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
- Reviewed:
- Description: Leukocyte telomeres shorten with age, and excessive shortening is associated with age-related cardiometabolic diseases. Exercise training may prevent disease through telomere length maintenance although the optimal amount of exercise that attenuates telomere attrition is unknown. Furthermore, the underlying molecular mechanisms responsible for the enhanced telomere maintenance observed in endurance athletes is poorly understood. We quantified the leukocyte telomere length and analyzed the expression of telomere-regulating genes in endurance athletes and healthy controls (both n = 61), using quantitative PCR. We found endurance athletes have significantly longer (7.1%, 208-416 nt) leukocyte telomeres and upregulated TERT (2.0-fold) and TPP1 (1.3-fold) mRNA expression compared with controls in age-adjusted analysis. The telomere length and telomere-regulating gene expression differences were no longer statistically significant after adjustment for resting heart rate and relative (V) over dotO(2 max) (all P > 0.05). Resting heart rate emerged as an independent predictor of leukocyte telomere length and TERT and TPP1 mRNA expression in stepwise regression models. To gauge whether volume of exercise was associated with leukocyte telomere length, we divided subjects into running and cycling tertiles (distance covered per week) and found individuals in the middle and highest tertiles had longer telomeres than individuals in the lowest tertile. These data emphasize the importance of cardiorespiratory fitness and exercise training in the prevention of biological aging. They also support the concept that moderate amounts of exercise training protects against biological aging, while higher amounts may not elicit additional benefits.
Longer leukocyte telomeres are associated with ultra-endurance exercise independent of cardiovascular risk factors
- Denham, Joshua, Nelson, Christopher, O'Brien, Brendan, Nankervis, Scott, Denniff, Matthew, Harvey, Jack, Marques, Francine, Codd, Veryan, Zukowska-Szczechowska, Ewa, Samani, Nilesh, Tomaszewski, Maciej, Charchar, Fadi
- Authors: Denham, Joshua , Nelson, Christopher , O'Brien, Brendan , Nankervis, Scott , Denniff, Matthew , Harvey, Jack , Marques, Francine , Codd, Veryan , Zukowska-Szczechowska, Ewa , Samani, Nilesh , Tomaszewski, Maciej , Charchar, Fadi
- Date: 2013
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 8, no. 7 (2013), p.
- Full Text:
- Reviewed:
- Description: Telomere length is recognized as a marker of biological age, and shorter mean leukocyte telomere length is associated with increased risk of cardiovascular disease. It is unclear whether repeated exposure to ultra-endurance aerobic exercise is beneficial or detrimental in the long-term and whether it attenuates biological aging. We quantified 67 ultra-marathon runners' and 56 apparently healthy males' leukocyte telomere length (T/S ratio) using real-time quantitative PCR. The ultra-marathon runners had 11% longer telomeres (T/S ratio) than controls (ultra-marathon runners: T/S ratio = 3.5±0.68, controls: T/S ratio = 3.1±0.41;
- Description: 2003011219
- Authors: Denham, Joshua , Nelson, Christopher , O'Brien, Brendan , Nankervis, Scott , Denniff, Matthew , Harvey, Jack , Marques, Francine , Codd, Veryan , Zukowska-Szczechowska, Ewa , Samani, Nilesh , Tomaszewski, Maciej , Charchar, Fadi
- Date: 2013
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 8, no. 7 (2013), p.
- Full Text:
- Reviewed:
- Description: Telomere length is recognized as a marker of biological age, and shorter mean leukocyte telomere length is associated with increased risk of cardiovascular disease. It is unclear whether repeated exposure to ultra-endurance aerobic exercise is beneficial or detrimental in the long-term and whether it attenuates biological aging. We quantified 67 ultra-marathon runners' and 56 apparently healthy males' leukocyte telomere length (T/S ratio) using real-time quantitative PCR. The ultra-marathon runners had 11% longer telomeres (T/S ratio) than controls (ultra-marathon runners: T/S ratio = 3.5±0.68, controls: T/S ratio = 3.1±0.41;
- Description: 2003011219
Oxygen uptake in maximal effort constant rate and interval running
- Pratt, Daniel, O'Brien, Brendan, Clark, Bradley
- Authors: Pratt, Daniel , O'Brien, Brendan , Clark, Bradley
- Date: 2013
- Type: Text , Journal article
- Relation: The Scientific World Journal Vol. 2013, no. (2013), p.
- Full Text:
- Reviewed:
- Description: This study investigated differences in average V̇O2 of maximal effort interval running to maximal effort constant rate running at lactate threshold matched for time. The average V̇O2 and distance covered of 10 recreational male runners (V̇O2 max: 4158 ± 390 mL·min-1) were compared between a maximal effort constant-rate run at lactate threshold (CRLT), a maximal effort interval run (INT) consisting of 2 min at V̇O2 max speed with 2 minutes at 50% of V̇O2 repeated 5 times, and a run at the average speed sustained during the interval run (CR submax). Data are presented as mean and 95% confidence intervals. The average V̇O2 for INT, 3451 (3269-3633) mL·min-1, 83% V̇O2 max, was not significantly different to CRLT, 3464 (3285-3643) mL·min-1, 84% V̇O2 max, but both were significantly higher than CR sub-max, 3464 (3285-3643) mL·min -1, 76% V̇O2 max. The distance covered was significantly greater in CLRT, 4431 (4202-3731) metres, compared to INT and CR sub-max, 4070 (3831-4309) metres. The novel finding was that a 20-minute maximal effort constant rate run uses similar amounts of oxygen as a 20-minute maximal effort interval run despite the greater distance covered in the maximal effort constant-rate run. © 2013 Daniel Pratt et al.
- Description: C1
- Authors: Pratt, Daniel , O'Brien, Brendan , Clark, Bradley
- Date: 2013
- Type: Text , Journal article
- Relation: The Scientific World Journal Vol. 2013, no. (2013), p.
- Full Text:
- Reviewed:
- Description: This study investigated differences in average V̇O2 of maximal effort interval running to maximal effort constant rate running at lactate threshold matched for time. The average V̇O2 and distance covered of 10 recreational male runners (V̇O2 max: 4158 ± 390 mL·min-1) were compared between a maximal effort constant-rate run at lactate threshold (CRLT), a maximal effort interval run (INT) consisting of 2 min at V̇O2 max speed with 2 minutes at 50% of V̇O2 repeated 5 times, and a run at the average speed sustained during the interval run (CR submax). Data are presented as mean and 95% confidence intervals. The average V̇O2 for INT, 3451 (3269-3633) mL·min-1, 83% V̇O2 max, was not significantly different to CRLT, 3464 (3285-3643) mL·min-1, 84% V̇O2 max, but both were significantly higher than CR sub-max, 3464 (3285-3643) mL·min -1, 76% V̇O2 max. The distance covered was significantly greater in CLRT, 4431 (4202-3731) metres, compared to INT and CR sub-max, 4070 (3831-4309) metres. The novel finding was that a 20-minute maximal effort constant rate run uses similar amounts of oxygen as a 20-minute maximal effort interval run despite the greater distance covered in the maximal effort constant-rate run. © 2013 Daniel Pratt et al.
- Description: C1