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Humberstone CE, Cormack S, Dunn E, Halperin I, Iverson D, Iredale F, Martin DT. Applying Ratio And Allometric Scaling To Strength Testing In Female Judoka. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000478288.56546.c8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Maloney MA, Farrow D, Dunn EC, Humberstone CE, Martin DT. Relationship Between Physical Factors and Non-Sport Specific Movement Skills in Australian Taekwondo Athletes. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000478290.33676.0e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Cormack S, Humberstone CE, Iredale F, Halperin I, Iverson D, Martin DT. Influence of Body Mass on Fitness Test Results in Australian Nationally-Ranked Judoka. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000478287.48923.0d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Drew M, Giles LS, Nasseer AM, Scullion P, Humberstone C, Reale R, Dunican I, Halperin I, Dunn E, Iverson D, Iredale F, Martin DT. Injuries Sustained During an International Judo Training Camp. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000479177.76778.1f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Dunn EC, Martin DT, Humberstone CE, Maloney MA, Blazevich T, Iredale F. Effects Of Tournament Judo On Haemoglobin And Protein In The Urine. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000478286.10805.0d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Martin DT, Dunican I, Reale R, Halperin I, Humberstone C, Dunn E, Maloney M, Lee H, Cormack S, Iredale F. Reliability And Validity Of The Single Leg, 3-hop Test In Australian Judoka. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000478289.56546.81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Martin DT, Bersohn MM, Waldo AL, Wathen MS, Choucair WK, Lip GY, Ip J, Holcomb R, Akar JG, Halperin JL. Randomized trial of atrial arrhythmia monitoring to guide anticoagulation in patients with implanted defibrillator and cardiac resynchronization devices. Eur Heart J 2015; 36:1660-8. [DOI: 10.1093/eurheartj/ehv115] [Citation(s) in RCA: 259] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 03/19/2015] [Indexed: 11/12/2022] Open
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Halson SL, Bartram J, West N, Stephens J, Argus CK, Driller MW, Sargent C, Lastella M, Hopkins WG, Martin DT. Does hydrotherapy help or hinder adaptation to training in competitive cyclists? Med Sci Sports Exerc 2015; 46:1631-9. [PMID: 24504431 DOI: 10.1249/mss.0000000000000268] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE Cold water immersion (CWI) may be beneficial for acute recovery from exercise, but it may impair long-term performance by attenuating the stimuli responsible for adaptation to training. We compared effects of CWI and passive rest on cycling performance during a simulated cycling grand tour. METHODS Thirty-four male endurance-trained competitive cyclists were randomized to CWI for four times per week for 15 min at 15°C or control (passive recovery) groups for 7 d of baseline training, 21 d of intensified training, and an 11-d taper. Criteria for completion of training and testing were satisfied by 10 cyclists in the CWI group (maximal aerobic power, 5.13 ± 0.21 W·kg; mean ± SD) and 11 in the control group (5.01 ± 0.41 W·kg). Each week, cyclists completed a high-intensity interval cycling test and two 4-min bouts separated by 30 min. CWI was performed four times per week for 15 min at 15°C. RESULTS Between baseline and taper, cyclists in the CWI group had an unclear change in overall 4-min power relative to control (2.7% ± 5.7%), although mean power in the second effort relative to the first was likely higher for the CWI group relative to control (3.0% ± 3.8%). The change in 1-s maximum mean sprint power in the CWI group was likely beneficial compared with control (4.4% ± 4.2%). Differences between groups for the 10-min time trial were unclear (-0.4% ± 4.3%). CONCLUSION Although some effects of CWI on performance were unclear, data from this study do not support recent speculation that CWI is detrimental to performance after increased training load in competitive cyclists.
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Affiliation(s)
- Shona L Halson
- 1AIS Physiology, Australian Institute of Sport, Belconnen, ACT, AUSTRALIA; 2School of Medicine, Griffith Health Institute, Griffith University, Gold Coast, AUSTRALIA; 3Appleton Institute for Behavioural Science, Central Queensland University, Adelaide, AUSTRALIA; and 4Sport Performance Research Institute, Auckland University of Technology, Auckland, NEW ZEALAND
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Martin DT, Gries H, Diggs BS, Koh JL, Selden NR, Schreiber MA, Kuang AA. Implementation of Tranexamic Acid to Reduce Blood Loss During Cranial Vault Remodeling for Craniosynostosis at a Single Institution. Plast Reconstr Surg 2014. [DOI: 10.1097/01.prs.0000455342.16278.23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Garvican-Lewis LA, Schumacher YO, Clark SA, Christian R, Menaspà P, Plowman J, Stephens B, Qi J, Fan R, He Y, Martin DT, Thompson KG, Gore CJ, Ma F. Stage racing at altitude induces hemodilution despite an increase in hemoglobin mass. J Appl Physiol (1985) 2014; 117:463-72. [DOI: 10.1152/japplphysiol.00242.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Plasma volume (PV) can be modulated by altitude exposure (decrease) and periods of intense exercise (increase). Cycle racing at altitude combines both stimuli, although presently no data exist to document which is dominant. Hemoglobin mass (Hbmass), hemoglobin concentration ([Hb]), and percent reticulocytes (%Retics) of altitude (ALT; n = 9) and sea-level (SL; n = 9) residents were measured during a 14-day cycling race, held at 1,146–4120 m, as well as during a simulated tour near sea level (SIM; n = 12). Hbmass was assessed before and on days 9 and 14 of racing. Venous blood was collected on days 0, 3, 6, 10, and 14. PV was calculated from Hbmass and [Hb]. A repeated-measures ANOVA was used to assess the impact of racing at altitude over time, within and between groups. [Hb] decreased significantly in all groups over time ( P < 0.0001) with decreases evident on the third day of racing. %Retics increased significantly in SL only ( P < 0.0001), with SL values elevated at day 6 compared with prerace ( P = 0.02), but were suppressed by the end of the race ( P = 0.0002). Hbmass significantly increased in SL after 9 ( P = 0.0001) and 14 ( P = 0.008) days of racing and was lower at the end of the race than midrace ( P = 0.018). PV increased in all groups ( P < 0.0001). Multiday cycle racing at altitude induces hemodilution of a similar magnitude to that observed during SL racing and occurs in nonacclimatized SL residents, despite an altitude-induced increase in Hbmass. Osmotic regulatory mechanisms associated with intense exercise appear to supersede acute enhancement of oxygen delivery at altitude.
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Affiliation(s)
- Laura A. Garvican-Lewis
- Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia
- Physiology, Australian Institute of Sport, Canberra, Australia
| | | | - Sally A. Clark
- Physiology, Australian Institute of Sport, Canberra, Australia
| | - Ryan Christian
- Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Paolo Menaspà
- Physiology, Australian Institute of Sport, Canberra, Australia
- Edith Cowan University, Perth, Australia; and
| | - Jamie Plowman
- Physiology, Australian Institute of Sport, Canberra, Australia
| | - Brian Stephens
- Physiology, Australian Institute of Sport, Canberra, Australia
| | - Jiliang Qi
- Qinghai Institute of Sports Science, Duoba, China
| | - Rongyun Fan
- Qinghai Institute of Sports Science, Duoba, China
| | - Yingying He
- Qinghai Institute of Sports Science, Duoba, China
| | - David T. Martin
- Physiology, Australian Institute of Sport, Canberra, Australia
| | - Kevin G. Thompson
- Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia
| | | | - Fuhai Ma
- Qinghai Institute of Sports Science, Duoba, China
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Martin DT, Schreiber MA. Modern resuscitation of hemorrhagic shock: what is on the horizon? Eur J Trauma Emerg Surg 2014; 40:641-56. [PMID: 26814779 DOI: 10.1007/s00068-014-0416-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 05/23/2014] [Indexed: 12/24/2022]
Abstract
PURPOSE Mortality rates among the severely injured remain high. The successful treatment of hemorrhagic shock relies on expeditious control of bleeding through surgical ligation, packing, or endovascular techniques. An important secondary concern in hemorrhaging patients is how to respond to the lost blood volume. A single method that is able to adequately address all needs of the exsanguinating patient has not yet been agreed upon, despite a large growth of knowledge regarding the causative factors of traumatic shock. METHODS A review of relevent literature was performed. CONCLUSIONS Many different trials are currently underway to discriminate ways to improve outcomes in the severely injured and bleeding patient. This paper will review: (1) recent advances in our understanding of the effects hemorrhagic shock has on the coagulation cascade and vascular endothelium, (2) recent research findings that have changed resuscitation, and (3) resuscitation strategies that are not widely used but under active investigation.
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Affiliation(s)
- D T Martin
- Division of Trauma, Critical Care, and Acute Care Surgery, Department of Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Mail Code L-611, Portland, OR, 97239, USA. .,Division of Trauma, Critical Care, and Acute Care Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Mail Code L-611, Portland, OR, 97239, USA.
| | - M A Schreiber
- Division of Trauma, Critical Care, and Acute Care Surgery, Department of Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Mail Code L-611, Portland, OR, 97239, USA. .,Division of Trauma, Critical Care, and Acute Care Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Mail Code L-611, Portland, OR, 97239, USA.
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Haakonssen EC, Martin DT, Burke LM, Jenkins DG. Energy expenditure of constant- and variable-intensity cycling: power meter estimates. Med Sci Sports Exerc 2014; 45:1833-40. [PMID: 23470312 DOI: 10.1249/mss.0b013e31828e18e6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The objective of this study is to compare the effects of constant- and variable-intensity cycling on gross efficiency (GE) and to compare estimates of energy expenditure (EE) made using indirect calorimetry (CAL) with estimates derived from commercially available power meters. METHODS Nine national team female road cyclists completed a GE test (GEtest = 4 min at approximately 45%, approximately 55%, approximately 65%, and approximately 75% maximal aerobic power (MAP)) before and after 10.5 min of either constant- (CON)- or variable- (VAR)-intensity cycling averaging approximately 55% MAP. GE measured before, after, and during CON and VAR cycling was compared. Total EE (kJ) for 10.5 min of VAR cycling was estimated using indirect CAL and compared with estimates on the basis of mechanical power [Schoberer Rad Messtechnik (SRM)] using the group mean GE, each athlete's mean GE, and each athlete's power to GE regression. RESULTS There was no effect of VAR on GEtests (P = 0.74). GE reduced from 19.1% ± 0.4% (mean ± SE) during the pretrial GEtests to 18.7% ± 0.4% during the posttrial GEtests (P < 0.05) in both conditions. Differences in GE (mean ± SD) measured during CON (18.4% ± 1.6%) and VAR cycling (18.6% ± 1.1%) were trivial (P = 0.28). SRM-based estimates of EE were most accurate when using individual athlete's power GE regression using Pre- and Post-VAR GEtest data combined (Δ(Equation is included in full-text article.)(%) ± 90% CI, 0.3 ± 0.8; R 0.98, P <0.001). Group mean estimates were within approximately 1% of CAL, although individual errors were approximately 11%. CONCLUSION Findings support the use of calibrated power meters for estimating cycling EE. For trained female road cyclists, total mechanical work (kJ) multiplied by 5.3 (GE = 19%) provides a valid estimation of total EE during variable-intensity cycling <75% MAP, although determining each athlete's GE improves accuracy greatly.
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Martin DT, Humberstone CE, Jones M, Nana A, Lee H, Burke LM. Relationship Between Lean Mass and Preferred Weight Category in Amateur Boxers. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000493431.16645.fd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Shimizu S, Oikawa R, Tsounapi P, Inoue K, Shimizu T, Tanaka K, Martin DT, Honda M, Sejima T, Tomita S, Saito M. Blocking of the ATP sensitive potassium channel ameliorates the ischaemia-reperfusion injury in the rat testis. Andrology 2014; 2:458-65. [PMID: 24604784 DOI: 10.1111/j.2047-2927.2014.00199.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 01/21/2014] [Accepted: 02/01/2014] [Indexed: 12/17/2022]
Abstract
There is increasing evidence that the effects of administered ATP sensitive potassium (KATP ) channel openers or blockers during ischaemia are still controversial in many organs/tissues. Testicular torsion detorsion which causes ischaemia-reperfusion (IR) injury, cannot be predicted, thus an effective drug should be administered during or after the ischaemia. The aim of this study was to examine whether the administration of KATP channel openers or blockers during ischaemia ameliorates IR injury in the testis. Eight-week-old male Sprague-Dawley rats were subjected to 2 h right testicular ischaemia followed by 24 h reperfusion. The selective mitochondrial (mito) KATP channel blocker, 5-hydroxydecanoate (5-HD) (40 mg/kg), the non-selective KATP channel blocker glibenclamide (5 mg/kg), the selective mito KATP channel opener diazoxide (10 mg/kg) and the non-selective KATP channel opener cromakalim (300 μg/kg) were administered intraperitoneally 15 min prior to the ischaemia or 75 min after the induction of ischaemia. Tissue damage was evaluated by malondialdehyde concentration, myeloperoxidase activity, histological evaluation and TdT-mediated dUTP nick end labelling assay in the testis. There was a significant increase in oxidative stress, neutrophil infiltration, histological damage and apoptosis in the testicular IR model. A significant reduction in the testicular IR injury was observed with the administration of glibenclamide, but not 5-HD, diazoxide or cromakalim during ischaemia. The administration of non-selective KATP channel blocker glibenclamide ameliorated the testicular IR injury. On the other hand, the selective mito KATP channel blocker, 5-HD and KATP channel openers did not reduce the testicular IR injury. These data suggest that blocking of the membrane KATP channel may have a protective effect during the testicular ischaemia. Glibenclamide could be an effective drug to manage the post-ischaemic injury caused by the testicular torsion-detorsion.
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Affiliation(s)
- S Shimizu
- Division of Molecular Pharmacology, Tottori University School of Medicine, Yonago, Japan
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Hoon MW, Hopkins WG, Jones AM, Martin DT, Halson SL, West NP, Johnson NA, Burke LM. Nitrate supplementation and high-intensity performance in competitive cyclists. Appl Physiol Nutr Metab 2014; 39:1043-9. [PMID: 24951296 DOI: 10.1139/apnm-2013-0574] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Consumption of inorganic nitrate (NO3(-)) is known to enhance endurance exercise performance in recreationally trained subjects. Here we report the effect on a high-intensity performance task in national-level cyclists. The performance test consisted of 2 cycle ergometer time trials of 4 min duration with 75 min between trials. In a randomized crossover design, 26 cyclists performed the test under the following 4 conditions (each separated by a 6-day washout): consumption of 70 mL of nitrate-rich beetroot juice at 150 min or 75 min before the first time trial, addition of a 35 mL "top-up dose" following the first time trial in the 150 min condition, and consumption of a placebo. A linear mixed model with adjustments for learning effects and athlete fitness (peak incremental power) was used to estimate effects on mean power, with probabilistic inferences based on a smallest important effect of 1.0%. Peak plasma nitrite (NO2(-)) concentration was greatest when nitrate was taken 75 min before the first time trial. Relative to placebo, the mean effect of all 3 nitrate treatments was unclear in the first time trial (1.3%, 90% confidence limits: ±1.7%), but possibly harmful in the second time trial (-0.3%, ±1.6%). Differences between nitrate treatments were unclear, as was the estimate of any consistent individual response to the treatments. Allowing for sampling uncertainty, the effect of nitrate on performance was less than previous studies. Under the conditions of our experiment, nitrate supplementation may be ineffective in facilitating high-intensity exercise in competitive athletes.
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Affiliation(s)
- Matthew W Hoon
- a School of Exercise and Sports Science, University of Sydney, Lidcombe, NSW, 2141, Australia
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Abbiss CR, Ross MLR, Garvican LA, Ross N, Pottgiesser T, Gregory J, Martin DT. The distribution of pace adopted by cyclists during a cross-country mountain bike World Championships. J Sports Sci 2013; 31:787-94. [PMID: 23521618 DOI: 10.1080/02640414.2012.751118] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The purpose of this study was to examine the distribution of pace self-selected by cyclists of varying ability, biological age and sex performing in a mountain bike World Championship event. Data were collected on cyclists performing in the Elite Male (ELITEmale; n = 75), Elite Female (ELITEfemale; n = 50), Under 23 Male (U23male; n = 62), Under 23 Female (U23female; n = 34), Junior Male (JNRmale; n = 71) and Junior Female (JNRfemale; n = 30) categories of the 2009 UCI Cross-Country Mountain Bike World Championships. Split times were recorded for the top, middle and bottom 20% of all finishers of each category. Timing splits were positioned to separate the course into technical and non-technical, uphill, downhill and rolling/flat sections. Compared with bottom performers, top performers in all male categories (ELITEmale, U23male, JNRmale) maintained a more even pace over the event as evidenced by a significantly lower standard deviation and range in average lap speed. Top performers, males, and ELITEmale athletes spent a lower percentage of overall race time on technical uphill sections of the course, compared with middle and bottom placed finishers, females, and JNRmale athletes, respectively. Better male performers adopt a more even distribution of pace throughout cross-country mountain events. Performance of lower placed finishers, females and JNRmale athletes may be improved by enhancing technical uphill cycling ability.
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Affiliation(s)
- Chris R Abbiss
- School of Exercise and Health Science, Edith Cowan University, Joondalup, Australia.
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Schumacher YO, Garvican LA, Pottgiesser T, Martin DT, Ahlgrim C, Gore CJ. Ethical considerations for experiments involving elite athletes and "doping". J Appl Physiol (1985) 2013; 114:1362. [PMID: 23681740 DOI: 10.1152/japplphysiol.01477.2012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Ross ML, Jeacocke NA, Laursen PB, Martin DT, Abbiss CR, Burke LM. Effects of lowering body temperature via hyperhydration, with and without glycerol ingestion and practical precooling on cycling time trial performance in hot and humid conditions. J Int Soc Sports Nutr 2012; 9:55. [PMID: 23245800 PMCID: PMC3549746 DOI: 10.1186/1550-2783-9-55] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 12/05/2012] [Indexed: 11/16/2022] Open
Abstract
Background Hypohydration and hyperthermia are factors that may contribute to fatigue and impairment of endurance performance. The purpose of this study was to investigate the effectiveness of combining glycerol hyperhydration and an established precooling technique on cycling time trial performance in hot environmental conditions. Methods Twelve well-trained male cyclists performed three 46.4-km laboratory-based cycling trials that included two climbs, under hot and humid environmental conditions (33.3 ± 1.1°C; 50 ± 6% r.h.). Subjects were required to hyperhydrate with 25 g.kg-1 body mass (BM) of a 4°C beverage containing 6% carbohydrate (CON) 2.5 h prior to the time trial. On two occasions, subjects were also exposed to an established precooling technique (PC) 60 min prior to the time trial, involving 14 g.kg-1 BM ice slurry ingestion and applied iced towels over 30 min. During one PC trial, 1.2 g.kg-1 BM glycerol was added to the hyperhydration beverage in a double-blind fashion (PC+G). Statistics used in this study involve the combination of traditional probability statistics and a magnitude-based inference approach. Results Hyperhydration resulted in large reductions (−0.6 to −0.7°C) in rectal temperature. The addition of glycerol to this solution also lowered urine output (330 ml, 10%). Precooling induced further small (−0.3°C) to moderate (−0.4°C) reductions in rectal temperature with PC and PC+G treatments, respectively, when compared with CON (0.0°C, P<0.05). Overall, PC+G failed to achieve a clear change in cycling performance over CON, but PC showed a possible 2% (30 s, P=0.02) improvement in performance time on climb 2 compared to CON. This improvement was attributed to subjects’ lower perception of effort reported over the first 10 km of the trial, despite no clear performance change during this time. No differences were detected in any other physiological measurements throughout the time trial. Conclusions Despite increasing fluid intake and reducing core temperature, performance and thermoregulatory benefits of a hyperhydration strategy with and without the addition of glycerol, plus practical precooling, were not superior to hyperhydration alone. Further research is warranted to further refine preparation strategies for athletes competing in thermally stressful events to optimize health and maximize performance outcomes.
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Affiliation(s)
- Megan Lr Ross
- Australian Institute of Sport, Belconnen, ACT, Australia.
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Garvican LA, Saunders PU, Pyne DB, Martin DT, Robertson EY, Gore CJ. Hemoglobin mass response to simulated hypoxia "blinded" by noisy measurement? J Appl Physiol (1985) 2012; 112:1797-8; author reply 1799. [PMID: 22589495 DOI: 10.1152/japplphysiol.00212.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Elmer SJ, Amann M, McDaniel J, Martin DT, Martin JC. Fatigue is specific to working muscles: no cross-over with single-leg cycling in trained cyclists. Eur J Appl Physiol 2012; 113:479-88. [PMID: 22806085 DOI: 10.1007/s00421-012-2455-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 07/03/2012] [Indexed: 11/29/2022]
Abstract
Fatigue induced via a maximal isometric contraction of a single limb muscle group can evoke a "cross-over" of fatigue that reduces voluntary muscle activation and maximum isometric force in the rested contralateral homologous muscle group. We asked whether a cross-over of fatigue also occurs when fatigue is induced via high-intensity endurance exercise involving a substantial muscle mass. Specifically, we used high-intensity single-leg cycling to induce fatigue and evaluated associated effects on maximum cycling power (P (max)) in the fatigued ipsilateral leg (FAT(leg)) as well as the rested contralateral leg (REST(leg)). On separate days, 12 trained cyclists performed right leg P (max) trials before and again 30 s, 3, 5, and 10 min after a cycling time trial (TT, 10 min) performed either with their right or left leg. Fatigue was estimated by comparing exercise-induced changes in P (max) and maximum handgrip isometric force (F (max)). Mean power produced during the right and left leg TTs did not differ (203 ± 8 vs. 199 ± 8 W). Compared to pre-TT, FAT(leg) P (max) was reduced by 22 ± 3 % at 30 s post-TT and remained reduced by 9 ± 2 % at 5 min post-TT (both P < 0.05). Despite considerable power loss in the FAT(leg), post-TT REST(leg) P (max) (596-603 W) did not differ from pre-TT values (596 ± 35 W). There were no alterations in handgrip F (max) (529-547 N). Our data suggest that any potential cross-over of fatigue, if present at all, was not sufficient to measurably compromise REST(leg) P (max) in trained cyclists. These results along with the lack of changes in handgrip F (max) indicate that impairments in maximal voluntary neuromuscular function were specific to working muscles.
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Affiliation(s)
- Steven J Elmer
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.
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Elmer SJ, Marshall CS, Wehmanen K, Amann M, McDaniel J, Martin DT, Martin JC. Effects of locomotor muscle fatigue on joint-specific power production during cycling. Med Sci Sports Exerc 2012; 44:1504-11. [PMID: 22343616 DOI: 10.1249/mss.0b013e31824fb8bd] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED Previous authors have reported reductions in maximum power after high-intensity cycling exercise. Exercise-induced changes in power produced by ankle, knee, and hip joint actions (joint-specific powers), however, have not been reported. PURPOSE Our purpose was to evaluate joint-specific power production during a cycling time trial (TT) and also to compare pre- to post-TT changes in maximal cycling (MAXcyc) joint-specific powers. METHODS Ten cyclists performed MAXcyc trials (90 rpm) before and after a 10-min TT (288 ± 10 W, 90 rpm). Pedal forces and limb kinematics were determined with a force-sensing pedal and an instrumented spatial linkage, respectively. Joint-specific powers were calculated and averaged over complete pedal cycles and over extension and flexion phases. RESULTS Pedal and joint-specific powers did not change during the TT. Compared to pre-TT, pedal power produced during post-TT MAXcyc was reduced by 32% ± 3% (P < 0.001). Relative changes in ankle plantarflexion (43% ± 5%) and knee flexion powers (52% ± 5%) were similar but were greater than changes in knee extension (12% ± 4%) and hip extension powers (28% ± 6%; both P < 0.05). Pedal and joint-specific powers produced during post-TT MAXcyc were greater than those powers produced during the final 3 s of the TT (P < 0.01). CONCLUSIONS Exercise-induced changes in MAXcyc power manifested with differential power loss at each joint action with ankle plantarflexion and knee flexion exhibiting relatively greater fatigue than knee extension and hip extension. However, changes in MAXcyc joint-specific powers were not presaged by changes in TT joint-specific powers. We conclude that fatigue induced via high-intensity cycling does not alter submaximal joint-specific powers but has distinct functional consequences for MAXcyc joint-specific powers.
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Affiliation(s)
- Steven J Elmer
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.
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73
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Ross MLR, Garvican LA, Jeacocke NA, Laursen PB, Abbiss CR, Martin DT, Burke LM. Novel precooling strategy enhances time trial cycling in the heat. Med Sci Sports Exerc 2011; 43:123-33. [PMID: 20508537 DOI: 10.1249/mss.0b013e3181e93210] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE To develop and investigate the efficacy of a new precooling strategy combining external and internal techniques on the performance of a cycling time trial (TT) in a hot and humid environment. METHODS Eleven well-trained male cyclists undertook three trials of a laboratory-based cycling TT simulating the course characteristics of the Beijing Olympic Games event in a controlled hot and humid environment (32°C-35°C at 50%-60% relative humidity). The trials, separated by 3-7 d, were undertaken in a randomized crossover design and consisted of the following: 1) CON-no treatment apart from the ad libitum consumption of cold water (4°C), 2) STD COOL-whole-body immersion in cold (10°C) water for 10 min followed by wearing a cooling jacket, or 3) NEW COOL-combination of consumption of 14 g of ice slurry ("slushie") per kilogram body mass made from a commercial sports drink while applying iced towels. RESULTS There was an observable effect on rectal temperature (T(rec)) before the commencement of the TT after both precooling techniques (STD COOL < NEW COOL < CON, P < 0.05), but pacing of the TT resulted in similar T(rec), HR, and RPE throughout the cycling protocol in all trials. NEW COOL was associated with a 3.0% increase in power (approximately 8 W) and a 1.3% improvement in performance time (approximately 1:06 min) compared with the CON trial, with the true likely effects ranging from a trivial to a large benefit. The effect of the STD COOL trial compared with the CON trial was "unclear." CONCLUSIONS This new precooling strategy represents a practical and effective technique that could be used by athletes in preparation for endurance events undertaken in hot and humid conditions.
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Affiliation(s)
- Megan L R Ross
- Australian Institute of Sport, Belconnen, Australian Capital Territory, Australia
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74
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Ruidiaz ME, Cortes-Mateos MJ, Sandoval S, Martin DT, Wang-Rodriguez J, Hasteh F, Wallace A, Vose JG, Kummel AC, Blair SL. Quantitative comparison of surgical margin histology following excision with traditional electrosurgery and a low-thermal-injury dissection device. J Surg Oncol 2011; 104:746-54. [DOI: 10.1002/jso.22012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 06/08/2011] [Indexed: 11/11/2022]
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75
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Yang J, Sandoval S, Alfaro JG, Aschemeyer S, Liberman A, Martin DT, Makale M, Kummel AC, Trogler WC. Red-luminescent europium (III) doped silica nanoshells: synthesis, characterization, and their interaction with HeLa cells. J Biomed Opt 2011; 16:066012. [PMID: 21721813 PMCID: PMC3133801 DOI: 10.1117/1.3593003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A simple method to fabricate Eu(3+) doped silica nanoshells particles with 100 and 200 nm diameters is reported. Amino polystyrene beads were used as templates, and an 8 to 10 nm thick silica gel coating was formed by the sol-gel reaction. After removing the template by calcination, porous dehydrated silica gel nanoshells of uniform size were obtained. The Eu(3+) doped silica nanoshells exhibited a red emission at 615 nm on UV excitation. The porous structure of the silica shell wall was characterized by transmission electron microscopy measurements, while particle size and zeta potentials of the particles suspended in aqueous solution were characterized by dynamic light scattering. Two-photon microscopy was used to image the nanoshells after assimilation by HeLa cancer cells.
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Affiliation(s)
- Jian Yang
- University of California, San Diego, Department of Chemistry and Biochemistry, 9500 Gilman Drive, La Jolla, California 92093, USA
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76
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Martin DT, McNitt S, Nesto RW, Rutter MK, Moss AJ. Cardiac Resynchronization Therapy Reduces the Risk of Cardiac Events in Patients With Diabetes Enrolled in the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT). Circ Heart Fail 2011; 4:332-8. [DOI: 10.1161/circheartfailure.110.959510] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Background—
Data are limited regarding whether the presence of diabetes mellitus (DM) influences the benefit of cardiac resynchronization with defibrillator therapy (CRT-D) in heart failure (HF) patients.
Methods and Results—
The effect of CRT-D was evaluated in 1817 patients who were enrolled in the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT). Patients were minimally symptomatic (New York Heart Association class I or II), with ejection fraction ≤0.30 and QRS ≥130 ms. We used Cox regression to determine hazard ratio (HR) of CRT-D versus implantable cardioverter-defibrillator (ICD) therapy for the risk of HF event or death, whichever came first (MADIT-CRT primary end point), in DM (n=552) and non-DM (n=1265) patients. Compared with the non-DM patients, those with DM had more coronary risk factors. During an average follow-up of 2.4 years, DM patients had significantly more primary end point events than non-DM patients (26.6% versus 18%,
P
<0.001). CRT-D was associated with a significant reduction in risk of primary end point in both DM (HR=0.56,
P
<0.001) and non-DM patients (HR=0.67,
P
=0.003). Compared with non-DM patients, CRT-D:ICD HRs in DM patients were lower in the total population, and in subgroups with ischemic cardiomyopathy (0.63 versus 0.64), nonischemic cardiomyopathy (0.39 versus 0.73), and left bundle-branch block (0.36 versus 0.50). There were no significant differences in ventricular remodeling, arrhythmia events, or device-related complications between DM and non-DM patients.
Conclusions—
Patients with diabetes, left ventricular dysfunction, mildly symptomatic HF, and wide QRS complex derive similar benefit from CRT-D compared with patients without diabetes.
Clinical Trial Registration—
URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT00180271.
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Affiliation(s)
- David T. Martin
- From the Department of Cardiovascular Medicine, Lahey Clinic Medical Center, Burlington, MA (D.T.M., R.W.N.); the Department of Medicine, University of Rochester Medical Center, Rochester, NY (S.M., A.J.M.); The Cardiovascular Research Group, School of Biomedicine, University of Manchester, United Kingdom (M.K.R.); Manchester Diabetes Centre, NIHR Manchester Biomedical Research Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Royal Infirmary, Manchester, United
| | - Scott McNitt
- From the Department of Cardiovascular Medicine, Lahey Clinic Medical Center, Burlington, MA (D.T.M., R.W.N.); the Department of Medicine, University of Rochester Medical Center, Rochester, NY (S.M., A.J.M.); The Cardiovascular Research Group, School of Biomedicine, University of Manchester, United Kingdom (M.K.R.); Manchester Diabetes Centre, NIHR Manchester Biomedical Research Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Royal Infirmary, Manchester, United
| | - Richard W. Nesto
- From the Department of Cardiovascular Medicine, Lahey Clinic Medical Center, Burlington, MA (D.T.M., R.W.N.); the Department of Medicine, University of Rochester Medical Center, Rochester, NY (S.M., A.J.M.); The Cardiovascular Research Group, School of Biomedicine, University of Manchester, United Kingdom (M.K.R.); Manchester Diabetes Centre, NIHR Manchester Biomedical Research Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Royal Infirmary, Manchester, United
| | - Martin K. Rutter
- From the Department of Cardiovascular Medicine, Lahey Clinic Medical Center, Burlington, MA (D.T.M., R.W.N.); the Department of Medicine, University of Rochester Medical Center, Rochester, NY (S.M., A.J.M.); The Cardiovascular Research Group, School of Biomedicine, University of Manchester, United Kingdom (M.K.R.); Manchester Diabetes Centre, NIHR Manchester Biomedical Research Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Royal Infirmary, Manchester, United
| | - Arthur J. Moss
- From the Department of Cardiovascular Medicine, Lahey Clinic Medical Center, Burlington, MA (D.T.M., R.W.N.); the Department of Medicine, University of Rochester Medical Center, Rochester, NY (S.M., A.J.M.); The Cardiovascular Research Group, School of Biomedicine, University of Manchester, United Kingdom (M.K.R.); Manchester Diabetes Centre, NIHR Manchester Biomedical Research Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Royal Infirmary, Manchester, United
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77
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Ebert TR, Brothers MD, Nelson JL, Flyger N, Martin DT, West GM, Gore CJ. Effects Of Moderate Altitude Training On Total Hemoglobin Mass And Hematology In World Class Sprint Cyclists. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000400782.66720.df] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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78
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Martin DT, Barnes C, Quod MJ, Ebert TR, Garvican LA, Martin JC. Does One Exponential Time Constant Explain the Power-Duration Relationship in National Team Road Cyclists? Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402942.28863.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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79
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Martin DT, Sandoval S, Ta CN, Ruidiaz ME, Cortes-Mateos MJ, Messmer D, Kummel AC, Blair SL, Wang-Rodriguez J. Quantitative automated image analysis system with automated debris filtering for the detection of breast carcinoma cells. Acta Cytol 2011; 55:271-80. [PMID: 21525740 DOI: 10.1159/000324029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 12/27/2010] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To develop an intraoperative method for margin status evaluation during breast conservation therapy (BCT) using an automated analysis of imprint cytology specimens. STUDY DESIGN Imprint cytology samples were prospectively taken from 47 patients undergoing either BCT or breast reduction surgery. Touch preparations from BCT patients were taken on cut sections through the tumor to generate positive margin controls. For breast reduction patients, slide imprints were taken at cuts through the center of excised tissue. Analysis results from the presented technique were compared against standard pathologic diagnosis. Slides were stained with cytokeratin and Hoechst, imaged with an automated fluorescent microscope, and analyzed with a fast algorithm to automate discrimination between epithelial cells and noncellular debris. RESULTS The accuracy of the automated analysis was 95% for identifying invasive cancers compared against final pathologic diagnosis. The overall sensitivity was 87% while specificity was 100% (no false positives). This is comparable to the best reported results from manual examination of intraoperative imprint cytology slides while reducing the need for direct input from a cytopathologist. CONCLUSION This work demonstrates a proof of concept for developing a highly accurate and automated system for the intraoperative evaluation of margin status to guide surgical decisions and lower positive margin rates.
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Affiliation(s)
- David T Martin
- Department of Electrical and Computer Engineering, University of California San Diego, San Diego, CA 92161, USA
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80
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Abbiss CR, Karagounis LG, Laursen PB, Peiffer JJ, Martin DT, Hawley JA, Fatehee NN, Martin JC. Single-leg cycle training is superior to double-leg cycling in improving the oxidative potential and metabolic profile of trained skeletal muscle. J Appl Physiol (1985) 2011; 110:1248-55. [PMID: 21330612 DOI: 10.1152/japplphysiol.01247.2010] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Single-leg cycling may enhance the peripheral adaptations of skeletal muscle to a greater extent than double-leg cycling. The purpose of the current study was to determine the influence of 3 wk of high-intensity single- and double-leg cycle training on markers of oxidative potential and muscle metabolism and exercise performance. In a crossover design, nine trained cyclists (78 ± 7 kg body wt, 59 ± 5 ml·kg(-1)·min(-1) maximal O(2) consumption) performed an incremental cycling test and a 16-km cycling time trial before and after 3 wk of double-leg and counterweighted single-leg cycle training (2 training sessions per week). Training involved three (double) or six (single) maximal 4-min intervals with 6 min of recovery. Mean power output during the single-leg intervals was more than half that during the double-leg intervals (198 ± 29 vs. 344 ± 38 W, P < 0.05). Skeletal muscle biopsy samples from the vastus lateralis revealed a training-induced increase in Thr(172)-phosphorylated 5'-AMP-activated protein kinase α-subunit for both groups (P < 0.05). However, the increase in cytochrome c oxidase subunits II and IV and GLUT-4 protein concentration was greater following single- than double-leg cycling (P < 0.05). Training-induced improvements in maximal O(2) consumption (3.9 ± 6.2% vs. 0.6 ± 3.6%) and time-trial performance (1.3 ± 0.5% vs. 2.3 ± 4.2%) were similar following both interventions. We conclude that short-term high-intensity single-leg cycle training can elicit greater enhancement in the metabolic and oxidative potential of skeletal muscle than traditional double-leg cycling. Single-leg cycling may therefore provide a valuable training stimulus for trained and clinical populations.
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Affiliation(s)
- Chris R Abbiss
- School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia.
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81
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Garvican LA, Pottgiesser T, Martin DT, Schumacher YO, Barras M, Gore CJ. The contribution of haemoglobin mass to increases in cycling performance induced by simulated LHTL. Eur J Appl Physiol 2010; 111:1089-101. [DOI: 10.1007/s00421-010-1732-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2010] [Indexed: 10/18/2022]
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82
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Garvican LA, Burge CM, Cox AJ, Clark SA, Martin DT, Gore CJ. Carbon monoxide uptake kinetics of arterial, venous and capillary blood during CO rebreathing. Exp Physiol 2010; 95:1156-66. [DOI: 10.1113/expphysiol.2010.054031] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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83
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Martin DT, Gregory J, Higham D, Ross MLR, Abbiss CR, Ross N. Cycling Power During MTB Hill Climbing and Laboratory Testing: Implications for Training. Med Sci Sports Exerc 2010. [DOI: 10.1249/01.mss.0000385372.90870.66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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84
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Garvican LA, Martin DT, McDonald W, Gore CJ. Seasonal variation of haemoglobin mass in internationally competitive female road cyclists. Eur J Appl Physiol 2010; 109:221-31. [DOI: 10.1007/s00421-009-1349-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2009] [Indexed: 11/24/2022]
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85
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Abstract
BACKGROUND Subjects with microvolt-level T-wave alternans (TWA) in association with structural heart disease have an increased risk for sudden cardiac death. The presence of diabetes (DM) is associated with an increased risk of sudden death but there is limited data on the impact of DM and previous myocardial infarction (MI) on TWA prevalence. METHODS We performed a case-control cross-sectional study in 140 patients referred for routine exercise testing within a large multispecialty clinic. All patients with a history of DM and MI status within the past year were eligible: group 1 (no DM or MI), group 2 (DM only), group 3 (MI only), group 4 (DM and MI). Patients performed a symptom-limited Bruce protocol exercise test with assessment of TWA by the spectral method using commercially available equipment. We used published criteria for the blinded interpretation of TWA; all tests not unequivocally negative were considered abnormal. RESULTS Age and gender were similar in all groups. The prevalence of abnormal TWA in groups 1-4 was 24%, 20%, 48%, and 62%, respectively (between group P = 0.002). Logistic regression analysis in all patients showed that abnormal TWA was related to prior MI [OR (95% CI): 4.0 (1.8-8.9), P < 0.001] but not to prevalent DM [0.9 (0.4-1.8), P = 0.72]. In patients with DM, the prevalence of abnormal TWA was related to reduced ejection fraction (P = 0.034) but not to BMI, DM duration, glycemic control, insulin use, or the presence of microvascular complications. CONCLUSION The presence of DM alone does not increase risk of abnormal TWA. Prospective studies are required to establish the prognostic value of TWA in patients with DM.
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Affiliation(s)
- David T Martin
- Department of Cardiovascular Medicine, Lahey Clinic Medical Center, Burlington, MA 01805, USA.
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86
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Quod MJ, Martin DT, Laursen PB, Gardner AS, Halson SL, Marino FE, Tate MP, Mainwaring DE, Gore CJ, Hahn AG. Practical precooling: effect on cycling time trial performance in warm conditions. J Sports Sci 2009; 26:1477-87. [PMID: 18949661 DOI: 10.1080/02640410802298268] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The purpose of this study was to compare the effects of two practical precooling techniques (skin cooling vs. skin + core cooling) on cycling time trial performance in warm conditions. Six trained cyclists completed one maximal graded exercise test (VO2(peak) 71.4 +/- 3.2 ml x kg(-1) x min(-1)) and four approximately 40 min laboratory cycling time trials in a heat chamber (34.3 degrees C +/- 1.1 degrees C; 41.2% +/- 3.0% rh) using a fixed-power/variable-power format. Cyclists prepared for the time trial using three techniques administered in a randomised order prior to the warm-up: (1) no cooling (control), (2) cooling jacket for 40 min (jacket) or (3) 30-min water immersion followed by a cooling jacket application for 40 min (combined). Rectal temperature prior to the time trial was 37.8 degrees C +/- 0.1 degrees C in control, similar in jacket (37.8 degrees C +/- 0.3 degrees C) and lower in combined (37.1 degrees C +/- 0.2 degrees C, P < 0.01). Compared with the control trial, time trial performance was not different for jacket precooling (-16 +/- 36 s, -0.7%; P = 0.35) but was faster for combined precooling (-42 +/- 25 s, - .8%; P = 0.009). In conclusion, a practical combined precooling strategy that involves immersion in cool water followed by the use of a cooling jacket can produce decrease in rectal temperature that persist throughout a warm-up and improve laboratory cycling time trial performance in warm conditions.
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Affiliation(s)
- Marc J Quod
- Department of Physiology, Australian Institute of Sport, Canberra, ACT, Australia
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87
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Ip J, Waldo AL, Lip GY, Rothwell PM, Martin DT, Bersohn MM, Choucair WK, Akar JG, Wathen MS, Rohani P, Halperin JL. Multicenter randomized study of anticoagulation guided by remote rhythm monitoring in patients with implantable cardioverter-defibrillator and CRT-D devices: Rationale, design, and clinical characteristics of the initially enrolled cohort The IMPACT study. Am Heart J 2009; 158:364-370.e1. [PMID: 19699858 DOI: 10.1016/j.ahj.2009.07.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 07/02/2009] [Indexed: 11/24/2022]
Abstract
Atrial fibrillation and atrial flutter are common cardiac arrhythmias associated with an increased risk of stroke in patients with additional risk factors. Anticoagulation ameliorates stroke risk, but because these arrhythmias may occur intermittently without symptoms, initiation of prophylactic therapy is often delayed until electrocardiographic documentation is obtained. The IMPACT study is a multicenter, randomized trial of remote surveillance technology in patients with implanted dual-chamber cardiac resynchronization therapy defibrillator (CRT-D) devices designed to test the hypothesis that initiation and withdrawal of oral anticoagulant therapy guided by continuous ambulatory monitoring of the atrial electrogram improve clinical outcomes by reducing the combined rate of stroke, systemic embolism, and major bleeding compared with conventional clinical management. For those in the intervention group, early detection of atrial high-rate episodes (AHRE) generates an automatic alert to initiate anticoagulation based on patient-specific stroke risk stratification. Subsequently, freedom from AHRE for predefined periods prompts withdrawal of anticoagulation to avoid bleeding. Patients in the control arm are managed conventionally, the anticoagulation decision prompted by incidental detection of atrial fibrillation or atrial flutter during routine clinical follow-up. The results will help define the clinical utility of wireless remote cardiac rhythm surveillance and help establish the critical threshold of AHRE burden warranting anticoagulant therapy in patients at risk of stroke. In this report, we describe the study design and baseline demographic and clinical features of the initial cohort (227 patients).
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Gardner AS, Martin DT, Jenkins DG, Dyer I, Van Eiden J, Barras M, Martin JC. Velocity-specific fatigue: quantifying fatigue during variable velocity cycling. Med Sci Sports Exerc 2009; 41:904-11. [PMID: 19276842 DOI: 10.1249/mss.0b013e318190c2cc] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED Previous investigators have quantified fatigue during short maximal cycling trials ( approximately 30 s) by calculating a fatigue index. Other investigators have reported a curvilinear power-pedaling rate relationship during short fatigue-free maximal cycling trials (<6 s). During maximal trials, pedaling rates may change with fatigue. Quantification of fatigue using fatigue index is therefore complicated by the power-pedaling rate relationship. PURPOSE The purpose of this study was to quantify fatigue while accounting for the effects of pedaling rate on power. METHODS Power and pedaling rate were recorded during Union Cycliste Internationale sanctioned 200-m time trials by eight male (height = 181.5 +/- 4.3 cm, mass = 87.0 +/- 8.0 kg) world-class sprint cyclists with SRM power meters and fixed-gear track bicycles. Data from the initial portion of maximal acceleration were used to establish maximal power-pedaling rate relationships. Fatigue was quantified three ways: 1) traditional fatigue index, 2) fatigue index modified to account for the power-pedaling rate relationship (net fatigue index), and 3) work deficit, the difference between actual work done and work that might have been accomplished without fatigue. RESULTS Fatigue index (55.4% +/- 6.4%) was significantly greater than net fatigue index (41.0% +/- 7.9%, P < 0.001), indicating that the power-pedaling rate relationship accounted for 14.3% +/- 7% of the traditional fatigue index value. Work deficit (23.3% +/- 6%) was significantly less than either measure of fatigue (P < 0.001). CONCLUSION Net fatigue index and work deficit account for the power-pedaling rate relation and therefore more precisely quantify fatigue during variable velocity cycling. These measures can be used to compare fatigue during different fatigue protocols, including world-class sprint cycling competition. Precise quantification of fatigue during elite cycling competition may improve evaluation of training status, gear ratio selection, and fatigue resistance.
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Affiliation(s)
- A Scott Gardner
- Department of Physiology, English Institute of Sport, Manchester, United Kingdom.
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89
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Abstract
Little is known about performance characteristics in the Winter Olympic sport of skeleton, in which athletes push and then drive a sled down an ice track. In this study, official race times from World Cups held on 11 tracks over four competitive seasons were analysed with linear models for athletes placed in the top 10 (35 males in 22 races; 28 females in 25 races). Mean run time ranged from approximately 50 to approximately 70 s between tracks. Predictability of individual performance expressed as race-to-race correlations was modest (0.36 for males and females). Differences between tracks in run-to-run variability expressed as coefficients of variation (men: 0.19-0.56%; women: 0.24-0.89%) paralleled differences in popular opinion of technical difficulty of the tracks. There was an inconsistent and overall small relationship between push time and performance time on different tracks (range of correlations, 0.57 to -0.14; mean, 0.21). The home advantages of 0.15% for men and 0.32% for women were trivial and substantial respectively in relation to the smallest important performance changes of 0.18% and 0.23%, derived from race-to-race variability. In conclusion, skeleton athletes show less variability in performance time than athletes in other sports, but tracks vary substantially in difficulty and race outcomes are largely unpredictable.
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Affiliation(s)
- Nicola Bullock
- Department of Physiology, Australian Institute of Sport, Belconnen, ACT, Australia.
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90
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Bullock N, Gulbin JP, Martin DT, Holland T, Marino FE. Performance Trends In Australian Skeleton Talent Transfer Athletes. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000354287.72872.65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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91
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Martin DT, Quod MJ, Lee H, Gore CJ. Cycling Efficiency In A Pro Tour Champion: A Case Study. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000356075.28952.1f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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92
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Quod MJ, Martin DT, Laursen PB, Gore CJ. Reliability Of The Power Profile Test: Assessing The Performance Capacity Of Road Cyclists. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000355504.24185.e8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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93
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Bullock N, Cox AJ, Martin DT, Marino FE. Resting salivary and plasma cortisol in elite athletes following long-haul travel from Australia to Canada. J Sci Med Sport 2009; 12:300-2. [DOI: 10.1016/j.jsams.2007.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 11/05/2007] [Accepted: 11/21/2007] [Indexed: 10/22/2022]
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94
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Bullock N, Gulbin JP, Martin DT, Ross A, Holland T, Marino F. Talent identification and deliberate programming in skeleton: Ice novice to Winter Olympian in 14 months. J Sports Sci 2009; 27:397-404. [DOI: 10.1080/02640410802549751] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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95
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Abbiss CR, Peiffer JJ, Wall BA, Martin DT, Laursen PB. Influence of starting strategy on cycling time trial performance in the heat. Int J Sports Med 2009; 30:188-93. [PMID: 19199209 DOI: 10.1055/s-0028-1104582] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The purpose of this study was to determine the influence of starting strategy on time trial performance in the heat. Eleven endurance trained male cyclists (30+/-5 years, 79.5+/-4.6 kg, VO(2max) 58.5+/-5.0 ml x kg x (-1) min(-1)) performed four 20-km time trials in the heat (32.7+/-0.7 degrees C and 55% relative humidity). The first time trial was completed at a self-selected pace (SPTT). During the following time trials, subjects performed the initial 2.5-km at power outputs 10% above (10% ATT), 10% below (10% BTT) or equal (ETT) to that of the average power during the initial 2.5-km of the self-selected trial; the remaining 17.5-km was self-paced. Throughout each time trial, power output, rectal temperature, skin temperature, heat storage, pain intensity and thermal sensation were taken. Despite significantly (P<0.05) greater power outputs for 10% BTT (273+/-45W) compared with the ETT (267+/-48W) and 10% ATT (265+/-41W) during the final 17.5-km, overall 20-km performance time was not significantly different amongst trials. There were no differences in any of the other measured variables between trials. These data show that varying starting power by +/-10% did not affect 20 km time trial performance in the heat.
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Affiliation(s)
- C R Abbiss
- School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Perth, Australia.
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96
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Bullock N, Martin DT, Ross A, Rosemond D, Jordan MJ, Marino FE. An acute bout of whole-body vibration on skeleton start and 30-m sprint performance. Eur J Sport Sci 2009. [DOI: 10.1080/17461390802579137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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97
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Gore CJ, Ashenden MJ, Sharpe K, Martin DT. Delta efficiency calculation in Tour de France champion is wrong. J Appl Physiol (1985) 2008; 105:1020; author reply 1021. [DOI: 10.1152/japplphysiol.90459.2008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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98
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99
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Bullock N, Martin DT, Ross A, Rosemond CD, Jordan MJ, Marino FE. Acute Effect of Whole-Body Vibration on Sprint and Jumping Performance in Elite Skeleton Athletes. J Strength Cond Res 2008; 22:1371-4. [DOI: 10.1519/jsc.0b013e31816a44b5] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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100
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Garvican LA, Martin DT, Clark MA, Quod M, Stephens B, Prommer N, Schmidt WF, Impellizzeri FM, Rampinini E, Sassi A, Gore CJ. The Time course of the Erythropoietic Response to Natural Altitude Training in Elite Endurance Cyclists. Med Sci Sports Exerc 2008. [DOI: 10.1249/01.mss.0000321672.78284.55] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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