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Billy Sperlich, Karsten Koehler, Hans-Christer Holmberg, Christoph Zinner and Joachim Mester

Purpose:

The aim of the study was to determine the cardiorespiratory and metabolic characteristics during intense and moderate table tennis (TT) training, as well as during actual match play conditions.

Methods:

Blood lactate concentration (Lac), heart rate (HR, beats per minute [bpm]), oxygen uptake (VO2), and energy expenditure (EE) in 7 male participants of the German junior national team (age: 14 ± 1 y, weight: 60.5 ± 5.6 kg height; 165 ± 8 cm) were examined during six training sessions (TS) and during an international match. The VO2 was measured continuously with portable gas analyzers. Lac was assessed every 1 to 3 min during short breaks.

Results:

Mean (peak) values for Lac, HR, VO2, and EE during the TS were 1.2 ± 0.7 (4.5) mmol·L–1, 135 ± 18 (184) bpm, 23.5 ± 7.3 (43.0) mL·kg–1· min–1, and 6.8 ± 2.0 (11.2) METs, respectively. During match play, mean (peak) values were 1.1 ± 0.2 (1.6) mmol·L–1, 126 ± 22 (189) bpm, 25.6 ± 10.1 (45.9) mL·kg–1·min–1, and 4.8 ± 1.4 (9.6) METs, respectively.

Conclusions:

For the frst time, cardiorespiratory and metabolic data in elite junior table tennis have been documented demonstrating low cardiorespiratory and metabolic demands during TT training and match play in internationally competing juniors.

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Nicolas Fabre, Stéphane Perrey, Loïc Arbez and Jean-Denis Rouillon

Purpose:

This study aimed (1) to determine whether paced breathing (synchronization of the expiration phase with poling time) would reduce the metabolic rate and dictate a lower rate of perceived exertion (RPE) than does spontaneous breathing and (2) to analyze the effects of paced breathing on poling forces and stride-mechanics organization during roller-ski skating exercises.

Methods:

Thirteen well-trained cross-country skiers performed 8 submaximal roller-skiing exercises on a motorized driven treadmill with 4 modes of skiing (2 skating techniques, V2 and V2A, at 2 exercise intensities) by using 2 patterns of breathing (unconscious vs conscious). Poling forces and stride-mechanics organization were measured with a transducer mounted in ski poles. Oxygen uptake (VO2) was continuously collected. After each bout of exercise RPE was assessed by the subject.

Results:

No difference was observed for VO2 between spontaneous and paced breathing conditions, although RPE was lower with paced breathing (P < .05). Upper-limb cycle time and recovery time were significantly (P < .05) increased by paced breathing during V2A regardless of the exercise intensity, but no changes for poling time were observed. A slight trend of increased peak force with paced breathing was observed (P = .055).

Conclusion:

The lack of a marked effect of paced breathing on VO2 and some biomechanical variables could be explained by the extensive experience of our subjects in cross-country skiing.

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Laura Lewis Frank, Janine T. Baer, Charles P. Lambert and Mark L. Anderson

The effect of fungal carbohydrases (Carbogen™ [C]) consumed with a meal replacement bar (MBR) on glucose metabolism and exercise performance was determined in 5 male competitive cyclists. After a 12-hour fast, subjects performed two 60-min cycling bouts at 80% V̇O2max followed by a time-to-exhaustion (TE) ride at 100% V̇O2max. One hour prior to each cycling bout, subjects ingested a MRB + 160-mg C or 160-mg CaCO3 placebo (PL) in a double-blind, counterbalanced fashion. Blood was drawn for determination of glucose, insulin, and lactate at: fasting, 1 hour post-feeding, minutes 30 and 60 of exercise, and after TE. Two-way ANOVA revealed a significant (p < .05) treatment and time effect for glucose, with C being higher than PL. Interaction effects were ob-· served for insulin and lactate. An increase in TE (min) at 100% V̇O2max was observed in the C versus PL trial (6.3 ± 3.4 vs. 4.4 ± 2.9, p < .001). A MRB+C may benefit cyclists due to increased BG and improved exercise performance.

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Amy C. Brown, Holden SH. MacRae and Nathan S. Turner

The purpose of this study was to determine whether ingestion of a multinutrient supplement containing 3 tricarboxylic-acid-cycle intermediates (TCAIs; pyridoxine-alpha-ketoglutarate, malate, and succinate) and other substances potentially supporting the TCA cycle (such as aspartate and glutamate) would improve cyclists’ time to exhaustion during a submaximal endurance-exercise test (~ 70% to 75% VO2peak) and rate of recovery. Seven well-trained male cyclists (VO2max 67.4 2.1 mL · kg–1 · min–1, 28.6 ± 2.4 y) participated in a randomized, double-blind crossover study for 7 wk. Each took either the treatment or a placebo 30 min before and after their normal training sessions for 3 wk and before submaximal exercise tests. There were no significant differences between the TCAI group (KI) and placebo group (P) in time to exhaustion during cycling (KI = 105 ± 18, P = 113 ± 11 min); respiratory-exchange ratio at 20-min intervals; blood lactate and plasma glucose before, after, and at 30-min intervals during exercise; perceived exertion at 20-min intervals during exercise; or time to fatigue after the 30-min recovery (KI = 16.1 ± 3.2, P = 15 ± 2 min). Taking a dietary sport supplement containing several TCAIs and supporting substances for 3 wk does not improve cycling performance at 75% VO2peak or speed recovery from previously fatiguing exercise.

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Cynthia M. Ferrara, Susan H. McCrone, David Brendle, Alice S. Ryan and Andrew P. Goldberg

The metabolic changes associated with the addition of 4 months of resistive exercise to an existing aerobic exercise program (AEX+RT, n = 7) were compared to a maintenance aerobic exercise program (AEX, n = 8) in overweight, older men. The subjects in this study had recently completed a 6-month aerobic exercise program (treadmill walking, 45 min/d, 2 d/wk). The AEX+RT group added 6 exercises on upper- and lower-body pneumatic-resistance machines (2 sets, 15 repetitions each, 2 d/wk) to an aerobic exercise program at ≥ 70% heart rate reserve for 30–40 min, 2 d/wk on treadmill, while the AEX group continued the same maintenance treadmill AEX program. There were no baseline differences in body weight, VO2max, or glucose metabolism between groups. The AEX+RT group increased upper- and lower-extremity strength by 28 ± 4% and 46 ± 6%, respectively (p < .05), despite a 9% decrease in VO2max (p < .05). VO2max did not change in the AEX group. There was no change in the fasting glucose or insulin levels, or the 3-h glucose responses to an oral glucose load in either group. The insulin responses decreased by 25 ± 4% in the AEX+RT group (p < .01) but did not change in the AEX group. In conclusion, the addition of resistive exercise training to an existing aerobic exercise program may improve insulin sensitivity in overweight, older men, and thus prevent the development of type 2 diabetes.

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Karen Reznik Dolins, Carol N. Boozer, Felicia Stoler, Matthew Bartels, Ronald DeMeersman and Isobel Contento

This study measured the effect of variable carbohydrate intake on time to exhaustion, variations in heart rate (HR), respiratory exchange ratio (RER), and rating of perceived exertion (RPE) in female endurance cyclists during an exercise trial. Subjects were 11 eumenorrheic women with maximal oxygen consumption (VO2max) 60.1 ± 5.1 ml/kg who habitually cycled at least 100 miles per week. In a crossover design, each woman was randomly assigned to a eucaloric diet providing 8, 5, or 3 g of CHO/kg of body weight. Subjects cycled at least 100 miles while adhering to the diet for 6 days. The exercise trial was performed on the 7th day, consisting of a 60 min cycle at 70% VO2max, followed by an increase in intensity to 90% VO2max until that intensity could no longer be maintained. Results indicated no difference in mean time to exhaustion, heart rate, or RPE. RER increased over time-elapsed (F = 40.4, p < .001) and across diets (F = 6.1, p = .015). Conclusions: Female endurance cyclists did not experience a difference in time to exhaustion, HR, or RPE with different levels of CHO intake during an endurance trial. RER varied with diet at submaximal intensities. Further research is needed to determine the optimal level of CHO intake for this population.

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Ronald L. Terjung, Ryszard Zarzeczny and H.T. Yang

Skeletal muscle mitochondrial capacity (mito), tissue blood flow (BF) capacity, and oxygen exchange capacity (e.g., DO2) appear to be well matched. The different skeletal muscle fiber types and muscle remodeled, due to inactivity >(e.g., related to aging or disease) or exercise training, exhibit widely differing aerobics capacities (V̇O2max). Yet, there are remarkably coordinated alterations in these 3 parameters in each of these conditions. With such a balance, there is likely shared control among these parameters in limiting (V̇O2max) of muscle, although this is a matter of considerable debate. The reduction in aerobic capacity in elderly can be improved by submaximal aerobic exercise training; this is related to increases in muscle mitochondria concentration and capillarity, but probably not BF capacity, as this is limited by central cardiovascular function. Thus, exercise-induced biochemical adaptations and angiogenesis occur in the elderly. The increase in muscle capillarity likely contributes to the increased oxygen exchange capacity, typical of endurance type training. The increase in [mito] appears essential to realize the increased in muscle V̇O2max with training and amplifies the rate-limiting influence of the muscle’s oxygen exchange capacity. Further, vascular remodeling induced by exercise in the elderly could be effective at improving flow capacity, if limited by peripheral obstruction. Thus, the limits to aerobic function specific to aged muscle appear most influenced by inactivity, whereas central cardiovascular changes impact whole body performance. Some may consider the aged myocyte as a small, inactive, normal myocyte in need of activity!

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Patrick J. O’Connor, Amanda L. Caravalho, Eric C. Freese and Kirk J. Cureton

Compounds found in the skins of grapes, including catechins, quercetin, and resveratrol, have been added to the diet of rodents and improved run time to exhaustion, fitness, and skeletal-muscle mitochondrial function. It is unknown if such effects occur in humans. The purpose of this experiment was to investigate whether 6 wk of daily grape consumption influenced maximal oxygen uptake (VO2max), work capacity, mood, perceived health status, inflammation, pain, and arm-function responses to a mild eccentric-exercise-induced arm-muscle injury. Forty recreationally active young adults were randomly assigned to consume a grape or placebo drink for 45 consecutive days. Before and after 42 d of supplementation, assessments were made of treadmill-running VO2max, work capacity (treadmill performance time), mood (Profile of Mood States), and perceived health status (SF-36 Health Survey). The day after posttreatment treadmill tests were completed, 18 high-intensity eccentric actions of the nondominant elbow flexors were performed. Arm-muscle inflammation, pain, and function (isometric strength and range of motion) were measured before and on 2 consecutive days after the eccentric exercise. Mixed-model ANOVA showed no significant effect of grape consumption on any of the outcomes. Six weeks of supplemental grape consumption by recreationally active young adults has no effect on VO2max, work capacity, mood, perceived health status, inflammation, pain, or physical-function responses to a mild injury induced by eccentric exercise.

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Shaea A. Alkahtani, Nuala M. Byrne, Andrew P. Hills and Neil A. King

Purpose:

Compensatory responses may attenuate the effectiveness of exercise training in weight management. The aim of this study was to compare the effect of moderate- and high-intensity interval training on eating behavior compensation.

Methods:

Using a crossover design, 10 overweight and obese men participated in 4-week moderate (MIIT) and high (HIIT) intensity interval training. MIIT consisted of 5-min cycling stages at ±20% of mechanical work at 45%VO2peak, and HIIT consisted of alternate 30-s work at 90%VO2peak and 30-s rests, for 30 to 45 min. Assessments included a constant-load exercise test at 45%VO2peak for 45 min followed by 60-min recovery. Appetite sensations were measured during the exercise test using a Visual Analog Scale. Food preferences (liking and wanting) were assessed using a computer-based paradigm, and this paradigm uses 20 photographic food stimuli varying along two dimensions, fat (high or low) and taste (sweet or nonsweet). An ad libitum test meal was provided after the constant-load exercise test.

Results:

Exerciseinduced hunger and desire to eat decreased after HIIT, and the difference between MIIT and HIIT in desire to eat approached significance (p = .07). Exercise-induced liking for high-fat nonsweet food tended to increase after MIIT and decreased after HIIT (p = .09). Fat intake decreased by 16% after HIIT, and increased by 38% after MIIT, with the difference between MIIT and HIIT approaching significance (p = .07).

Conclusions:

This study provides evidence that energy intake compensation differs between MIIT and HIIT.

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Asok Kumar Ghosh, A. Abdul Rahaman and Rabindarjeet Singh

The purpose of the study was to investigate whether a combination of sago and soy protein ingested during moderate-intensity cycling exercise can improve subsequent high-intensity endurance capacity compared with a carbohydrate in the form of sago and with a placebo. The participants were 8 male recreational cyclists with age, weight, and VO2max of 21.5 ± 1.1 yr, 63.3 ± 2.4 kg, and 39.9 ± 1.1 ml · kg−1 · min−1, respectively. The design of the study was a randomized, double-blind placebo-controlled crossover comprising 60 min of exercise on a cycle ergometer at 60% VO2max followed by a time-to-exhaustion ride at 90% VO2max. The sago feeding provided 60 g of carbohydrate, and the sago-soy combination provided 52.5 g of carbohydrate and 15 g of protein, both at 20-min intervals during exercise. Times to exhaustion for the placebo, sago, and sago-soy supplementations were 4.09 ± 1.28, 5.49 ± 1.20, and 7.53 ± 2.02 min, respectively. Sago-soy supplementation increased endurance by 84% (44–140%; p < .001) and by 37% (15–63%; p < .05) relative to placebo and sago, respectively. The plasma insulin response was elevated above that with placebo during sago and sago-soy supplementations. The authors conclude that a combination of sago and soy protein can delay fatigue during high-intensity cycling.