High-intensity Exercise Performance Research Articles

The Effect of Recovery Strategies on Lactate Clearance and High-Intensity Exercise Performance

The Effect of Recovery Strategies on Lactate Clearance and High-Intensity Exercise Performance

Metabolic Consequences of Resistive Force Selection During Cycle Ergometry Exercise

The purpose of this study was to compare power outputs and blood lactate concentrations ([La−]B) following 30 s of maximal cycle ergometry when resistive forces were derived from total-body mass (TBM) or fat-free mass (FFM). Differences (P < 0.05) in peak power output (PPO), pedal velocity (PV) and resistive forces (RF) were observed when the TBM and FFM protocols were compared (953 ± 114 W vs. 1020 ± 134 W; 134 ± 8 rpm vs. 141 ± 7 rpm; 6 ± 1 kg vs. 5 ± 1 kg, respectively). Blood lactate values ([La−]B) increased (P < 0.01) postexercise for both protocols and were significantly greater for TBM (10.6 ± 1.2 mmol.l−1 vs 11.6 ± 1.1 mmol.l−1, P < 0.05). These findings indicate that the FFM resistive force protocol may maximise adenosinotriphosphate-phosphocreatine (ATP-PC) utilisation with smaller contributions from anaerobic glycolysis when compared with TBM. These results may have important implications in the assessment of high intensity exercise performance.

High-intensity exercise and recovery during short-term supplementation with creatine plus a protein-carbohydrate formula

Objective. To determine the effect of short-term creatine supplementation plus a protein-carbohydrate formula on high-intensity exercise performance and recovery. Design. A repeated-measures, experimental study, employing a randomised, double-blind, placebo-controlled, group comparison design was used. Interventions. Thirty active but not sprint-trained male subjects were randomly assigned to 1 of 3 groups: creatine plus protein-carbohydrate formula (CRF); creatine only (CRE); and control (CON). All groups were exposed to the same high-intensity sprint exercise programme, 3 times per week for 30 days. Main outcome measures. Dependant variables included total repeat sprint distance, fatigue index, perceived muscle pain, and blood lactate, urea, creatine kinase, and cortisol concentrations. Results. All groups significantly (p ≤ 0.05) increased total sprint distance and decreased blood urea concentrations. There were no significant changes in blood lactate or cortisol concentrations in any group. CRF showed significant decreases (p ≤ 0.05) in fatigue index, muscle pain, and creatine kinase concentration. However, no significant differences were found between groups. Conclusion. Short-term creatine supplementation with or without protein-carbohydrate supplementation does not appear to enhance performance or recovery significantly over high-intensity exercise training alone in non-sprint-trained individuals. A longer trial period may be required to evaluate effect on recovery more conclusively. In addition, the prime importance of physical conditioning, and in particular task-specific exercise training, in stimulating performance and recovery adaptations is highlighted. South African Journal of Sports Medicine Vol. 18 (4) 2006: pp. 136-140

Carnosine supplementation does not improve high intensity exercise performance

Carnosine supplementation does not improve high intensity exercise performance

The brain and fatigue: New opportunities for nutritional interventions?

It is clear that the cause of fatigue is complex, influenced by events occurring in both the periphery and the central nervous system. Work conducted over the last 20 years has focused on the role of brain serotonin and catecholamines in the development of fatigue, and the possibility that manipulation of neurotransmitter precursors may delay the onset of fatigue. While there is some evidence that branched-chain amino acid and tyrosine ingestion can influence perceived exertion and some measures of mental performance, the results of several apparently well-controlled laboratory studies have not demonstrated a positive effect on exercise capacity or performance under temperate conditions. As football is highly reliant upon the successful execution of motor skills and tactics, the possibility that amino acid ingestion may help to attenuate a loss in cognitive function during the later stages of a game would be desirable, even in the absence of no apparent benefit to physical performance. There are several reports of enhanced performance of high-intensity intermittent exercise with carbohydrate ingestion, but at present it is difficult to separate the peripheral effects from any potential impact on the central nervous system. The possibility that changes in central neurotransmission play a role in the aetiology of fatigue when exercise is performed in high ambient temperatures has recently been examined, although the significance of this in relation to the pattern of activity associated with football has yet to be determined.

Creatine Supplementation Plus Aerobic Training

It has been demonstrated that creatine supplementation can improve performance in intermittent high intensity and short term exercise. Recently, some findings have indicated that creatine supplementation affects glucose metabolism. PURPOSE: This study aimed to examine the effects of creatine supplementation plus aerobic training on glucose tolerance in sedentary healthy male METHODS: Subjects (n=16) were randomly divided in two groups in a double-blind fashion: 1) creatine (CR-dose: 0.3g/day/kg of body weight for the first week, and 0.15g/day/kg of body weight for the next three months); 2) placebo (PL-equal amount of dextrose). Both groups underwent moderate aerobic training, three times for week, 40 minutes for session. The oral glucose tolerance test (OGTT) was performed and fasting insulin was assessed at baseline (PRE), after four (POST 4), eight (POST 8) and twelve weeks (POST 12). RESULTS: Glucose tolerance was similar between groups at PRE. However, CR demonstrated significant decrease in the area under the curve (from OGTT) at the moments POST 4, 8 and 12 (PRE: 15675 ± 2170 mg/dl/min; POST 4: 13525 ± 1698 mg/dl/min; POST 8: 12515 ± 1712 mg/dl/min; POST 12: 13000 ± 2177mg/dl/min; p < 0.05). This difference was not observed among PL. Furthermore, the peak plasma glucose was reduced in CR at POST 4 when compared to PL (CR: 115vs.PL: 167 mg/dl; p=0.04). No significant differences are noted in fasting insulin. CONCLUSIONS: These results suggest that creatine supplementation plus aerobic training can improve glucose tolerance, but not affects fasting insulin. These findings can lead to future research with diabetics subjects.

The Effects of Different Warm-up Loads [Routines] at Equal Total Workload for High Intensity Exercise Performance

The Effects of Different Warm-up Loads [Routines] at Equal Total Workload for High Intensity Exercise Performance

Effects of Training on Lactate Kinetics Parameters and their Influence on Short High-Intensity Exercise Performance

The purpose of the present study was to relate the training-induced alterations in lactate kinetics parameters to the concomitant changes in time to exhaustion (T(lim)) at a work rate corresponding to maximal oxygen uptake (Pa(peak)). Eight subjects performed before and after training i) an incremental exercise up to exhaustion to determine Pa(peak), ii) a 5-min 90 % Pa(peak) exercise followed by a 90-min passive recovery to determine an individual blood lactate recovery curve fitted to the bi-exponential time function: La(t) = La(0) + A1(1 - e -gamma1 x t) + A2(1 - e -gamma2 x t), and iii) a time to exhaustion at Pa peak to determine T lim. A biopsy of the vastus lateralis muscle was made before and after training. The training programme consisted in pedalling on a cycle ergometer 2 h a day, 6 days a week, for 4 weeks. Training-induced increases (p < 0.05) in Pa(peak), muscle capillary density, citrate synthase activity, gamma2 that denotes the lactate removal ability (from 0.0547 +/- 0.0038 to 0.0822 +/- 0.0071 min (-1)) and T(lim) (from 299 +/- 23 to 486 +/- 63 s), decreases (p < 0.05) in activities of lactate dehydrogenase (LDH) and muscle type of LDH, the phosphofructokinase/citrate synthase activities ratio and the estimated net amount of lactate released (NALR) during exercise recovery (from 66.5 +/- 8.6 to 47.2 +/- 11.1 mmol) were also observed. The improvement of T (lim) with training was related to the increase in gamma2 (r = 0.74, p = 0.0367) and to the decrease in NALR (r = 0.77, p = 0.0250). These results suggest that the post-training greater ability to remove lactate from the organism and reduced muscle lactate accumulation during exercise account for the concomitant improvement of the time to exhaustion during high-intensity exercise performed at the same relative work rate.

The Effect of Carbohydrate Mouth Rinse on 1-h Cycle Time Trial Performance

To investigate the possible role of carbohydrate (CHO) receptors in the mouth in influencing exercise performance, seven male and two female endurance cyclists (VO(2max) 63.2 +/- 2.7 (mean +/- SE) mL.kg*(-1).min(-1)) completed two performance trials in which they had to accomplish a set amount of work as quickly as possible (914 +/- 40 kJ). On one occasion a 6.4% maltodextrin solution (CHO) was rinsed around the mouth for every 12.5% of the trial completed. On the other occasion, water (PLA) was rinsed. Subjects were not allowed to swallow either the CHO solution or water, and each mouthful was spat out after a 5-s rinse. Performance time was significantly improved with CHO compared with PLA (59.57 +/- 1.50 min vs 61.37 +/- 1.56 min, respectively, P = 0.011). This improvement resulted in a significantly higher average power output during the CHO compared with the PLA trial (259 +/- 16 W and 252 +/- 16 W, respectively, P = 0.003). There were no differences in heart rate or rating of perceived exertion (RPE) between the two trials (P > 0.05). The results demonstrate that carbohydrate mouth rinse has a positive effect on 1-h time trial performance. The mechanism responsible for the improvement in high-intensity exercise performance with exogenous carbohydrate appears to involve an increase in central drive or motivation rather than having any metabolic cause. The nature and role of putative CHO receptors in the mouth warrants further investigation.

Exercise in the heat: challenges and opportunities

Exercise in the heat poses a formidable challenge to the body's ability to control its internal environment due to the high rates of metabolic heat production and heat gain by physical transfer from the environment. In an attempt to restrict the rise in core temperature, an increased rate of sweat secretion onto the skin is invoked. This may limit the rise in core temperature, and can prolong the time before a limiting temperature is attained, but it does so at the cost of a loss of body water and electrolytes. The effects of the diminished blood volume are offset to some extent by cardiovascular adaptations, including an increased heart rate and an increased peripheral resistance, but these are insufficient to maintain functional capacity when blood volume is reduced. Prior dehydration will impair performance in both prolonged exercise and short-term high-intensity exercise. Athletes living and training in the heat may experience chronic hypohydration due to inadequate replacement of fluid losses. The negative consequences of exercise in the heat are attenuated to some extent by a period of adaptation, and by the ingestion of water or other appropriate fluids. Optimum fluid replacement strategies will depend on the exercise task, the environmental conditions and the individual physiological characteristics of the athlete. Manipulation of pre-exercise body temperature can also influence exercise performance and may be a strategy that can be used by athletes competing in stressful environments.

Effects of Sodium Citrate Ingestion on Exercise Performance at Moderate Altitude

1173 Sodium citrate has been used as a potential ergogenic aid for improving high-intensity exercise performance. To date, few studies have looked at whether sodium citrate is effective at improving high-intensity exercise performance at altitude. PURPOSE: The purpose of this study was to examine the effect of sodium citrate ingestion and moderate altitude exposure on high-intensity exercise performance. METHODS: Six healthy, active subjects (mean age = 24.8 ± 10.4 yr) were tested at sea level (SL1), upon acute exposure to 3400 m (ALT1), two weeks following acclimatization at 3400 m (ALT2), and upon return to sea level (SL2). Each subject performed a cycle ergometer exercise protocol corresponding to approximately 110% of their VO2 max until exhaustion. The protocol was performed twice under each condition, once after ingestion of a placebo, and once after ingestion of a sodium citrate drink (.4 gms of sodium citrate per kg of body weight in 500 ml of water). Time duration to exhaustion and changes in blood lactate levels post-exercise were measured. RESULTS: There were no significant increases (p>0.05) in time to exhaustion at ALT 1 for the placebo (144.5 ± 43.8 sec) compared to the sodium citrate condition (149.2 ± 27.0 sec) or at any of the other three (SL1, ALT2, SL2) conditions. Blood lactate levels during ALT2 were significantly increased (p<0.05) relative to SL1 (8.62 mmol ± 5.43 with placebo vs. 13.78 mmol ± 4.21 with sodium citrate ingestion). Under all other conditions, no significant blood lactate differences were observed. Some gastrointestinal distress was also experienced as a side effect of sodium citrate ingestion. CONCLUSION: It would therefore appear that under all four conditions explored, sodium citrate had no significant effect on high-intensity exercise performance. It should be noted however, that differences in time to exhaustion experienced during the ALT1, ALT2, and SL2 conditions, while not statistically significant, could be great enough to cause an improvement in athletic performance.

Patients with classic congenital adrenal hyperplasia have decreased epinephrine reserve and defective glucose elevation in response to high-intensity exercise.

Classic congenital hyperplasia (CAH) is characterized by impaired adrenocortical function with a decrease in cortisol and aldosterone secretion and an increase in androgen secretion. Adrenomedullary function is also compromised due to developmental defects in the formation of the adrenal medulla, leading to decreased production of epinephrine. To examine the response to a natural stressful stimulus in patients with classic CAH, we studied hormonal, metabolic, and cardiorespiratory parameters in response to a standardized high-intensity exercise protocol in nine adolescent patients with CAH and nine healthy controls matched for gender, age, and percent body fat. The same relative workload was applied, based on individual maximal aerobic capacity, and all patients received their usual glucocorticoid and mineralocorticoid replacement. When compared with their normal counterparts, patients with CAH had significantly lower epinephrine levels both at baseline and at peak exercise (P < 0.01), whereas norepinephrine levels did not differ. Blood glucose concentrations were similar at baseline, but the normal exercise-induced rise observed in the healthy controls was significantly blunted in the CAH patients (P < 0.01). Peak heart rate was also lower in CAH patients than healthy controls (P < 0.05). As expected, the normal exercise-induced increase in cortisol was not observed in patients with CAH. No significant differences were found in serum levels of insulin, glucagon, GH, lactate and free fatty acids, blood pressure, or ability to sustain exercise between the two groups. Patients with CAH replaced with glucocorticoids have decreased adrenomedullary reserve and impaired exercise-induced changes in glucose but normal short-term high-intensity exercise performance. Whether the combination of epinephrine and cortisol deficiency poses a risk for hypoglycemia and/or decreased endurance during long-term physical stress has to be determined.

トリ胸肉抽出物(CBEX^&lt;TM&gt;)の経口摂取が高強度間欠的運動パフォーマンスに及ぼす影響

The histidine-containing dipeptide carnosine (p-alanyl-L-histidine) exists widely in the skeletal muscle of vertebrates. The biological role of carnosine has not been well established, but it is believed to act as a cytosolic buffering agent. We prepared an extract of chicken breast meat that is an abundant source of carnosine and its related dipeptide anserine (β-alanyl-1-methyl-L-histidine). The purpose of this study was to examine the effects of extract (CBEX^<TM>) supplementation on high-intensity intermittent exercise performance. Eight male subjects performed two experimental trials (CBEX and placebo treatment). Each trial consisted of two intermittent cycle ergometer sprints separated by a 20-min recovery period. Intermittent exercise consisted often 5-s maximal sprints with 25-s of recovery between each sprint. The subjects were given 190 g of experimental soup containing either 40 g of CBEX or no CBEX 30 min before each trial. Anserine and its related amino acid in plasma were detectable 30 min after CBEX supplementation. However, plasma carnosine was not detectable. In the CBEX group, the subjects exhibited high power during the latter half of intermittent exercise compared with the placebo group. These results suggest that pre-exercise CBEX supplementation improves intermittent exercise performance, possibility by restraining the decrease of intracellular pH and thereby delaying the onset of fatigue.

Effect of ribose supplementation on resynthesis of adenine nucleotides after intense intermittent training in humans

The effect of oral ribose supplementation on the resynthesis of adenine nucleotides and performance after 1 wk of intense intermittent exercise was examined. Eight subjects performed a random double-blind crossover design. The subjects performed cycle training consisting of 15 x 10 s of all-out sprinting twice per day for 7 days. After training the subjects received either ribose (200 mg/kg body wt; Rib) or placebo (Pla) three times per day for 3 days. An exercise test was performed at 72 h after the last training session. Immediately after the last training session, muscle ATP was lowered (P < 0.05) by 25 +/- 2 and 22 +/- 3% in Pla and Rib, respectively. In both Pla and Rib, muscle ATP levels at 5 and 24 h after the exercise were still lower (P < 0.05) than pretraining. After 72 h, muscle ATP was similar (P > 0.05) to pretraining in Rib (24.6 +/- 0.6 vs. 26.2 +/- 0.2 mmol/kg dry wt) but still lower (P < 0.05) in Pla (21.1 +/- 0.5 vs. 26.0 +/- 0.2 mmol/kg dry wt) and higher (P < 0.05) in Rib than in Pla. Plasma hypoxanthine levels after the test performed at 72 h were higher (P < 0.05) in Rib compared with Pla. Mean and peak power outputs during the test performed at 72 h were similar (P > 0.05) in Pla and Rib. The results support the hypothesis that the availability of ribose in the muscle is a limiting factor for the rate of resynthesis of ATP. Furthermore, the reduction in muscle ATP observed after intense training does not appear to be limiting for high-intensity exercise performance.

Endurance Capacity and High-Intensity Exercise Performance Responses to a High-Fat Diet

The effects of adaptation to a high-fat diet on endurance performance are equivocal, and there is little data regarding the effects on high-intensity exercise performance. This study examined the effects of a high-fat/moderate protein diet on submaximal, maximal, and supramaximal performance. Twenty non-highly trained men were assigned to either a high-fat/moderate protein (HFMP; 61% fat diet) (n = 12) or a control (C; 25% fat) group (n = 8). A maximal oxygen consumption test, two 30-s Wingate anaerobic tests, and a 45-min timed ride were performed before and after 6 weeks of diet and training. Body mass decreased significantly (-2.2 kg; p < or = .05) in HFMP subjects. Maximal oxygen consumption significantly decreased in the HFMP group (3.5 +/- 0.14 to 3.27 +/- 0.09 L x min(-1)) but was unaffected when corrected for body mass. Perceived exertion was significantly higher during this test in the HFMP group. Main time effects indicated that peak and mean power decreased significantly during bout 1 of the Wingate sprints in the HFMP (-10 and -20%, respectively) group but not the C (-8 and -16%, respectively) group. Only peak power was lower during bout 1 in the HFMP group when corrected for body mass. Despite significantly reduced RER values in the HFMP group during the 45-min cycling bout, work output was significantly decreased (-18%). Adaptation to a 6-week HFMP diet in non-highly trained men resulted in increased fat oxidation during exercise and small decrements in peak power output and endurance performance. These deleterious effects on exercise performance may be accounted for in part by a reduction in body mass and/or increased ratings of perceived exertion.

High Level of Skeletal Muscle Carnosine Contributes to the Latter Half of Exercise Performance during 30-s Maximal Cycle Ergometer Sprinting.

The histidine-containing dipeptide carnosine (beta-alanyl-L-histidine) has been shown to significantly contribute to the physicochemical buffering in skeletal muscles, which maintains acid-base balance when a large quantity of H(+) is produced in association with lactic acid accumulation during high-intensity exercise. The purpose of the present study was to examine the relations among the skeletal muscle carnosine concentration, fiber-type distribution, and high-intensity exercise performance. The subjects were 11 healthy men. Muscle biopsy samples were taken from the vastus lateralis at rest. The carnosine concentration was determined by the use of an amino acid autoanalyzer. The fiber-type distribution was determined by the staining intensity of myosin adenosinetriphosphatase. The high-intensity exercise performance was assessed by the use of 30-s maximal cycle ergometer sprinting. A significant correlation was demonstrated between the carnosine concentration and the type IIX fiber composition (r=0.646, p<0.05). The carnosine concentration was significantly correlated with the mean power per body mass (r=0.785, p<0.01) during the 30-s sprinting. When dividing the sprinting into 6 phases (0-5, 6-10, 11-15, 16-20, 21-25, 26-30 s), significant correlations were observed between the carnosine concentration and the mean power per body mass of the final 2 phases (21-25 s: r=0.694, p<0.05; 26-30 s: r=0.660, p<0.05). These results indicated that the carnosine concentration could be an important factor in determining the high-intensity exercise performance.

Creatine supplementation: exploring the role of the creatine kinase/phosphocreatine system in human muscle.

The effect of oral creatine supplementation on high-intensity exercise performance has been extensively studied over the past ten years and its ergogenic potential in young healthy subjects is now well documented. Recently, research has shifted from performance evaluation towards elucidating the mechanisms underlying enhanced muscle functional capacity after creatine supplementation. In this review, we attempt to summarise recent advances in the understanding of potential mechanisms of action of creatine supplementation at the level of skeletal muscle cells. By increasing intracellular creatine content, oral creatine ingestion conceivably stimulates operation of the creatine kinase (CK)/phosphocreatine (PCr) system, which in turn facilitates muscle relaxation. Furthermore, evidence is accumulating to suggest that creatine supplementation can beneficially impact on muscle protein and glycogen synthesis. Thus, muscle hypertrophy and glycogen supercompensation are candidate factors to explain the ergogenic potential of creatine ingestion. Additional issues discussed in this review are the fibre-type specificity of muscle creatine metabolism, the identification of responders versus non-responders to creatine intake, and the scientific background concerning potential side effects of creatine supplementation.

Selective serotonin reuptake inhibitors: Their effect on high-intensity exercise performance

Parise G, Bosman MJ, Boecker DR, Barry MJ, Tarnopolsky MA. Selective serotonin reuptake inhibitors: their effect on high-intensity exercise performance. Arch Phys Med Rehabil 2001;82:867-71. Objective: To determine the neuromuscular and performance effects of acute and long-term exposure to selective serotonin reuptake inhibitors (SSRIs). Design: Two randomized, double-blind, crossover studies. Setting: Departments of Kinesiology and Medicine, McMaster University, Hamilton, Ont, Canada. Participants: Eleven healthy, college-aged men in the acute study; 12 healthy, college-aged men in the chronic study. Interventions: In the acute study, subjects were given a placebo and fluoxetine (40mg) 6 hours before testing, in the chronic study, they were given fluoxetine (40mg/d) and an identical placebo for 2 weeks before testing. Main Outcome Measures: Target measures were maximum voluntary contractions (MVCs), evoked peak torque, and percentage of motor unit activation for muscle strength and central drive. Repeated Wingate cycle ergometer tests were used to measure anaerobic power, capacity, and fatigue index. V̇O2max tests (80%, 90%) were used to measure time to exhaustion and cardiorespiratory responses. Results: In the acute study phase, MVC was lower for fluoxetine versus placebo (p =.05) and a slight fatigue resistance was measured in the repeated Wingate tests for the fluoxetine group; however, there were no affects on any other measured variable. In the chronic study phase, minute ventilation was lower for the fluoxetine trial (p <.05); however, there were no treatment affects on any of the other measurements. Conclusion: Acute and chronic SSRI intake does not effect strength or high-intensity exercise performance in young adult men. © 2001 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

SKELETAL MUSCLE CARNOSINE LEVEL MAY CONTRIBUTE TO SUPERIOR PERFORMANCE DURING HIGH INTENSITY EXERCISE

Dipeptide carnosine (β-alanyl-L-histidine) has been shown to contribute significantly to physico-chemical buffering in skeletal muscle, which maintains acid-base balance when large quantities of hydrogen ions are produced in association with lactic acid accumulation during high intensity exercise. The purpose of this study was to examine relationships among skeletal muscle carnosine level, fiber type distribution and high intensity exercise performance. The subjects were twenty healthy men. Muscle biopsy samples were taken from the vastus lateralis at rest. Carnosine level were determined using an amino acid AutoAnalyzer. Fiber type distribution was determined by staining intensity of myosin adenosinetriphosphatase. High intensity exercise performance was assessed using 30-s cycle ergometer sprinting. Significant (P < 0.05) interrelationships were demonstrated between carnosine level and type II fiber composition. Superior sprint performance was associated with type II fiber composition and carnosine level. When dividing the 30-s sprinting into 6 phases (0–5, 6–10, 11–15, 16–20, 21–25, 26–30 s), significant correlations were observed between carnosine level and mean power of the latter 3 phases (16–20 s: P < 0.05, 21–25 s: P < 0.01 and 26–30 s: P < 0.05). These results indicate that carnosine level may be an important determinant of high intensity exercise performance.

The influence of whole-body vs. torso pre-cooling on physiological strain and performance of high-intensity exercise in the heat

Little research has been reported examining the effects of pre-cooling on high-intensity exercise performance, particularly when combined with strategies to keep the working muscle warm. This study used nine active males to determine the effects of pre-cooling the torso and thighs (LC), pre-cooling the torso (ice-vest in 3°C air) while keeping the thighs warm (LW), or no cooling (CON: 31°C air), on physiological strain and high-intensity (45-s) exercise performance (33°C, 60% rh). Furthermore, we sought to determine whether performance after pre-cooling was influenced by a short exercise warm-up. The 45-s test was performed at different ( P<0.05) mean core temperature [(rectal+oesophageal)/2] [CON: 37.3±0.3 (S.D.), LW: 37.1±0.3, LC: 36.8±0.4°C] and mean skin temperature (CON: 34.6±0.6, LW: 29.0±1.0, LC: 27.2±1.2°C) between all conditions. Forearm blood flow prior to exercise was also lower in LC (3.1±2.0 ml 100 ml tissue −1 min −1) than CON (8.2±2.5, P=0.01) but not LW (4.3±2.6, P=0.46). After an exercise warm-up, muscle temperature ( T m) was not significantly different between conditions (CON: 37.3±1.5, LW: 37.3±1.2, LC: 36.6±0.7°C, P=0.16) but when warm-up was excluded, T m was lower in LC (34.5±1.9°C, P=0.02) than in CON (37.3±1.0) and LW (37.1±0.9). Even when a warm-up was performed, torso+thigh pre-cooling decreased both peak (−3.4±3.8%, P=0.04) and mean power output (−4.1±3.8%, P=0.01) relative to the control, but this effect was markedly larger when warm-up was excluded (peak power −7.7±2.5%, P=0.01; mean power −7.6±1.2%, P=0.01). Torso-only pre-cooling did not reduce peak or mean power, either with or without warm-up. These data indicate that pre-cooling does not improve 45-s high-intensity exercise performance, and can impair performance if the working muscles are cooled. A short exercise warm-up largely removes any detrimental effects of a cold muscle on performance by increasing T m.