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Long-distance race car drivers are classified as athletes. The sport is physically and mentally demanding, requiring long hours of practice. Therefore, optimal dietary intake is essential for health and performance of the athlete. The aim of the study was to evaluate dietary intake and to compare the data with dietary recommendations for athletes and for the general adult population according to the German Nutrition Society (DGE). A 24-h dietary recall during a competition preparation phase was obtained from 16 male race car drivers (28.3 ± 6.1 years, body mass index (BMI) of 22.9 ± 2.3 kg/m2). The mean intake of energy, nutrients, water and alcohol was recorded. The mean energy, vitamin B2, vitamin E, folate, fiber, calcium, water and alcohol intake were 2124 ± 814 kcal/day, 1.3 ± 0.5 mg/day, 12.5 ± 9.5 mg/day, 231.0 ± 90.9 ug/day, 21.4 ± 9.4 g/day, 1104 ± 764 mg/day, 3309 ± 1522 mL/day and 0.8 ± 2.5 mL/day respectively. Our study indicated that many of the nutrients studied, including energy and carbohydrate, were below the recommended dietary intake for both athletes and the DGE.
How much is too much? - a case report of nutritional supplement use of a high-performance athlete
(2011)
Although dietary nutrient intake is often adequate, nutritional supplement use is common among elite athletes. However, high-dose supplements or the use of multiple supplements may exceed the recommended daily allowance (RDA) of particular nutrients or even result in a daily intake above tolerable upper limits (UL). The present case report presents nutritional intake data and supplement use of a highly trained male swimmer competing at international level. Habitual energy and micronutrient intake were analysed by 3 d dietary reports. Supplement use and dosage were assessed, and total amount of nutrient supply was calculated. Micronutrient intake was evaluated based on RDA and UL as presented by the European Scientific Committee on Food, and maximum permitted levels in supplements (MPL) are given. The athlete's diet provided adequate micronutrient content well above RDA except for vitamin D. Simultaneous use of ten different supplements was reported, resulting in excess intake above tolerable UL for folate, vitamin E and Zn. Additionally, daily supplement dosage was considerably above MPL for nine micronutrients consumed as artificial products. Risks and possible side effects of exceeding UL by the athlete are discussed. Athletes with high energy intake may be at risk of exceeding UL of particular nutrients if multiple supplements are added. Therefore, dietary counselling of athletes should include assessment of habitual diet and nutritional supplement intake. Educating athletes to balance their diets instead of taking supplements might be prudent to prevent health risks that may occur with long-term excess nutrient intake.
The study was conducted to investigate the quantity and the main food sources of carbohydrate (CHO) intake of junior elite triathletes during a short-term moderate (MOD; 12 km swimming, 100 km cycling, 30 km running per wk) and intensive training period (INT; 23 km swimming, 200 km cycling, 45 km running per wk). Self-reported dietary-intake data accompanied by training protocols of 7 male triathletes (18.1 +/- 2.4 yr, 20.9 +/- 1.4 kg/m(2)) were collected on 7 consecutive days during both training periods in the same competitive season. Total energy and CHO intake were calculated based on the German Food Database. A paired t test was applied to test for differences between the training phases (alpha = .05). CHO intake was slightly higher in INT than in MOD (9.0 +/- 1.6 g . kg(-1) . d(-1) vs. 7.8 +/- 1.6 g . kg(-1) . d(-1); p = .041). Additional CHO in INT was mainly ingested during breakfast (115 +/- 37 g in MOD vs. 175 +/- 23 g in INT; p = .002) and provided by beverages (280.5 +/- 97.3 g/d vs. 174.0 +/- 58.3 g/d CHO; p = .112). Altogether, main meals provided approximately two thirds of the total CHO intake. Pre- and postexercise snacks additionally supplied remarkable amounts of CHO (198.3 +/- 84.3 g/d in INT vs. 185.9 +/- 112 g/d CHO in MOD; p = .231). In conclusion, male German junior triathletes consume CHO in amounts currently recommended for endurance athletes during moderate to intensive training periods. Main meals provide the majority of CHO and should therefore not be skipped. CHO-containing beverages, as well as pre- and postexercise snacks, may provide a substantial amount of CHO intake in training periods with high CHO requirements.
Exercise may increase reactive oxygen species production, which might impair cell integrity and contractile function of muscle cells. However, little is known about the effect of regular exercise on the antioxidant status of adolescents. Purpose: This study aimed to evaluate the impact of exercise on the antioxidant status and protein modifications in adolescent athletes. Methods: In 90 athletes and 18 controls (16 +/- 2 yr), exercise-related energy expenditure was calculated on the basis of a 7-d activity protocol. Antioxidant intake and plasma concentrations of alpha-tocopherol, carotenoids, and uric acid were analyzed. Plasma antioxidant activity was determined by Trolox equivalent (TE) antioxidant capacity and electron spin resonance spectrometry. Protein modifications were assessed with structural changes of transthyretin using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Data were analyzed by two-way ANOVA and post hoc by the Tukey-Kramer test (alpha = 0.05). Results: Antioxidant intake correlated with energy intake and was within the recommended daily allowance for vitamins C and E and beta-carotene. Plasma levels of neither nutritional antioxidants nor uric acid differed between the groups. TE antioxidant capacity was higher in athletes (men = 1.47 perpendicular to 0.2 mmol TE per liter, women = 1.45 perpendicular to 0.2 mmol TE per liter) compared with controls (men = 1.17 +/- 0.04 mmol TE per liter, women = 1.14 +/- 0.04 mmol TE per liter) and increased with exercise-related energy expenditure (P = 0.007). Transthyretin cysteinylation rate differed between the groups, with the highest rate of protein modifications in moderately active subjects (P = 0.007). Conclusions: Results suggest that if the nutritional choice of athletes is well balanced, enough antioxidants are provided to meet recommended amounts. Moreover, regular exercise increases blood antioxidant capacity in young athletes, whereas chronic exercise was not shown to promote protein modifications. Thus, in young athletes who are sufficiently supplied with antioxidants, beneficial effects of exercise on antioxidant status rather than on oxidative stress may be anticipated.
Background: Athletes may differ in their resting metabolic rate (RMR) from the general population. However, to estimate the RMR in athletes, prediction equations that have not been validated in athletes are often used. The purpose of this study was therefore to verify the applicability of commonly used RMR predictions for use in athletes. Methods: The RMR was measured by indirect calorimetry in 17 highly trained rowers and canoeists of the German national teams (BMI 24 +/- 2 kg/m(2), fat-free mass 69 +/- 15 kg). In addition, the RMR was predicted using Cunningham (CUN) and Harris-Benedict (HB) equations. A two-way repeated measures ANOVA was calculated to test for differences between predicted and measured RMR (alpha = 0.05). The root mean square percentage error (RMSPE) was calculated and the Bland-Altman procedure was used to quantify the bias for each prediction. Results: Prediction equations significantly underestimated the RMR in males (p < 0.001). The RMSPE was calculated to be 18.4% (CUN) and 20.9% (HB) in the entire group. The bias was 133 kcal/24 h for CUN and 202 kcal/24 h for HB. Conclusions: Predictions significantly underestimate the RMR in male heavyweight endurance athletes but not in females. In athletes with a high fat-free mass, prediction equations might therefore not be applicable to estimate energy requirements. Instead, measurement of the resting energy expenditure or specific prediction equations might be needed for the individual heavyweight athlete.
Adequate energy intake in adolescent athletes is considered important. Total energy expenditure (TEE) can be calculated from resting energy expenditure (REE) and physical activity level (PAL). However, validated PAL recommendations are available for adult athletes only. Purpose was to comprise physical activity data in adolescent athletes and to establish PAL recommendations for this population. In 64 competitive athletes (15.3 +/- 1.5yr, 20.5 +/- 2.0kg/m(2)) and 14 controls (15.1 +/- 1.1yr, 21 +/- 2.1kg/m(2)) TEE was calculated using 7-day activity protocols validated against doubly-labeled water. REE was estimated by Schofield-HW equation, and PAL was calculated as TEE:REE. Observed PAL in adolescent athletes (1.90 +/- 0.35) did not differ compared with controls (1.84 +/- 0.32, p = .582) and was lower than recommended for adult athletes by the WHO. In conclusion, applicability of PAL values recommended for adult athletes to estimate energy requirements in adolescent athletes must be questioned. Instead, a PAL range of 1.75-2.05 is suggested.
Dietary records are often biased, especially those of overweight individuals. The purpose of the study was to investigate underreporting among persons of normal weight with a very high energy intake (El).
The total energy expenditure (TEE) of 16 elite athletes (BMI 24 +/- 2 kg/m(2)) and 17 controls (BMI 23 3 kg/m2) was measured using the doubly-labeled water technique (DLW, 14d). El was estimated using 2 x 3-day dietary records. Underreporters were identified by BLACK'S cut-off (El:TEE < 0.76). 44% of athletes (El: 3584 824 kcal/d; TEE: 4621 1460 kcal/d) and 29% of controls (El: 2552 680 kcal/d; TEE: 3151 822 kcal/d) were identified as underreporters. TEE explains 52% of underreporting. In summary, a high energy intake seems to strongly predict underreporting. Prevalence and magnitude of underreporting increase with increasing energy intake.
Achilles (AT) and patellar tendons (PT) are commonly affected by tendinopathy in adult athletes but prevalence of symptoms and morphological changes in adolescents is unclear. The study aimed to determine prevalence of tendinopathy and intratendinous changes in ATs and PTs of adolescent athletes. A total of 760 adolescent athletes (13.0 +/- 1.9 years; 160 +/- 13cm; 50 +/- 14kg) were examined. History, local clinical examination, and longitudinal Doppler ultrasound analysis for both ATs and PTs were performed including identification of intratendinous echoic changes and vascularization. Diagnosis of tendinopathy was complied clinically in case of positive history of tendon pain and tendon pain on palpation. Achilles tendinopathy was diagnosed in 1.8% and patellar tendinopathy in 5.8%. Vascularizations were visible in 3.0% of ATs and 11.4% of PTs, hypoechogenicities in 0.7% and 3.2% as well as hyperechogenicities in 0% and 0.3%, respectively. Vascularizations and hypoechogenicities were statistically significantly more often in males than in females (P0.02). Subjects with patellar tendinopathy had higher prevalence of structural intratendinous changes than those without PT symptoms (P0.001). In adolescent athletes, patellar tendinopathy is three times more frequent compared with Achilles tendinopathy. Longitudinal studies are necessary to investigate physiological or pathological origin of vascularizations and its predictive value in development of tendinopathy.
Tendon adaptation due to mechanical loading is controversially discussed. However, data concerning the development of tendon thickness in adolescent athletes is sparse. The purpose of this study was to examine possible differences in Achilles (AT) and patellar tendon (PT) thickness in adolescent athletes while considering age, gender and sport-specific loading. In 500 adolescent competitive athletes of 16 different sports and 40 recreational controls both ATs and PTs were sonographically measured. Subjects were divided into 2 age groups (< 13; ≥ 13 years) and 6 sport type categories (ball, combat, and water sports, combined disciplines, cycling, controls). In addition, 3 risk groups (low, moderate, high) were created according to the athlete’s risk of developing tendinopathy. AT and PT thickness did not significantly differ between age groups (AT/PT:<13: 5.4±0.7 mm/3.6±0.5 mm;≥13: 5.3±0.7 mm/3.6±0.5 mm). In both age groups males presented higher tendon thickness than females (p<0.001). AT thickness was highest in ball sports/cyclists and lowest in controls (p≤0.002). PT thickness was greatest in water sports and lowest in controls (p=0.02). High risk athletes presented slightly higher AT thickness compared to the low risk group (p=0.03). Increased AT and PT thickness in certain sport types compared to controls supports the hypothesis of structural tendon adaptation due to sport-specific loading.
Intra- and interrater variability of sonographic investigations of patella and achilles tendons
(2012)
Background: Clinical examinations of tendon disorders routinely include ultrasound examinations, despite the fact that availability of data concerning validity criteria of these measurements are limited. The present study therefore aims to evaluate the reliability of measurements of Achilles- and Patella tendon diameter and in the detection of structural adaptations.
Materials and Methods: In 14 healthy, recreationally active subjects both asymptomatic Achilles (AT) and patella tendons (PT) were measured twice by two examiners in a test-retest design. Besides the detection of anteroposterior (a.p.-) and mediolateral (m.l.-) diameters, areas of hypoechogenicity and neovascularisation were registered. Data were analysed descriptively with calculation of test-retest variability (TRV), intraclass-correlation coefficient (ICC) and Bland and Altman's plots with bias and 95% limits of agreement (LOA).
Results: Intra- and interrater differences of AT- and PT-a.p.-diameter varied from 0.2 - 1.2 mm, those of AT- and PT-m.l-diameter from 0.7-5.1 mm. Areas of hypoechogenicity were visible in 24% of the tendons, while 15% showed neovascularisations. Intrarater AT-a.p.-diameters showed sparse deviations (TRV 4.5-7.4%; ICC 0.60-0.84; bias -0.05-0.07 mm; LOA-0.6-0.5 to -1.1 - 1.0 mm), while interrater AT- and PT-m.l.-diameters were highly variable (TRV 13.7-19.7%; ICC 0.11-0.20; bias -1.4-4.3 mm; LOA-5.5-2.7 to -10.5 - 1.9 mm).
Conclusion: Our results suggest that the measurement of AT- and PT-a.p.-diameters is a reliable parameter. In contrast, reproducibility of AT- and PT-m.l.-diameters is questionable. The study corroborates the presence of hypoechogenicity and neovascularisation in asymptomatic tendons.
Reliability of ultrasound measurements for subcutaneous adipose tissue in elite canoe athletes
(2014)
Subcutaneous adipose tissue (SAT) measurements with ultrasound have recently been introduced to assess body fat in elite athletes. However, appropriate protocols and data on various groups of athletes are missing. We investigated intra-rater reliability of SAT measurements using ultrasound in elite canoe athletes. 25 international level canoeists (18 male, 7 female; 23 +/- 4 years; 81 +/- 11 kg; 1.83 +/- 0.09 m; 20 +/- 3 training h/wk) were measured on 2 consecutive days. SAT was assessed with B-mode ultrasound at 8 sites (ISAK): triceps, subscapular, biceps, iliac crest, supraspinal, abdominal, front thigh, medial calf, and quantified using image analysis software. Data was analyzed descriptively (mean +/- SD, [range]). Coefficient of variation (CV %), intraclass correlation coefficient (ICC, 2.1) and absolute (LoA) and ratio limits of agreement (RLoA) were calculated for day-to-day reliability. Mean sum of SAT thickness was 30.0 +/- 19.4 mm [8.0, 80.1 mm], with 3.9 +/- 1.8 mm [1.2 mm subscapular, 8.0 mm abdominal] for individual sites. CV for the sum of sites was 4.7 %, ICC 0.99, LoA 1.7 +/- 3.6 mm, RLoA 0.940 (*/divided by 1.155). Measuring SAT with ultrasound has proved to have excellent day-to-day reliability in elite canoe athletes. Recommendations for standardization of the method will further increase accuracy and reproducibility.
THIS ARTICLE REVIEWS THE AVAILABLE LITERATURE ON WHICH PROTEINS, AMINO ACIDS, OR COMBINATION OF BOTH SEEM TO BE OPTIMAL TO ENHANCE HYPERTROPHY AFTER RESISTANCE EXERCISE IN YOUNG ADULTS. DEPENDING ON THE CONTENT OF ESSENTIAL AMINO ACIDS AND PARTICULARLY LEUCINE, EITHER AN IMMEDIATE INGESTION OF similar to 20 G MILK PROTEIN FOLLOWED BY A SIMILAR AMOUNT similar to 1 HOUR LATER, OR A SINGLE BOLUS OF similar to 40 G SEEMS TO BE SUITABLE. GREATER AMOUNTS MIGHT BE NECESSARY IF A PROTEIN OF LOWER QUALITY IS CHOSEN ( I. E., PLANT-BASED PROTEINS) TO MATCH THE REQUIRED AMINO ACID QUANTITIES AND FACILITATE MUSCLE GROWTH.
Background Preparticipation examinations (PPE) are frequently used to evaluate eligibility for competitive sports in adolescent athletes. Nevertheless, the effectiveness of these examinations is under debate since costs are high and its validity is discussed controversial.
Purpose To analyse medical findings and consequences in adolescent athletes prior to admission to a sports school.
Methods In 733 adolescent athletes (318 girls, 415 boys, age 12.3+/-0.4, 16 sports disciplines), history and clinical examination (musculoskeletal, cardiovascular, general medicine) was performed to evaluate eligibility. PPE was completed by determination of blood parameters, ECG at rest and during ergometry, echocardiography and x-rays and ultrasonography if indicated. Eligibility was either approved or rated with restriction. Recommendations for therapy and/or prevention were given to the athletes and their parents.
Results Historical (h) and clinical (c) findings (eg, pain, verified pathologies) were more frequent regarding the musculoskeletal system (h: 120, 16.4%; c: 247, 33.7%) compared to cardiovascular (h: 9, 1.2%; c: 23, 3.1%) or general medicine findings (h: 116, 15.8%; c: 71, 9.7%). ECG at rest was moderately abnormal in 46 (6.3%) and severely abnormal in 25 athletes (3.4%). Exercise ECG was suspicious in 25 athletes (3.4%). Relevant echocardiographic abnormalities were found in 17 athletes (2.3%). In 52 of 358 cases (14.5%), x-rays led to diagnosis (eg, Spondylolisthesis). Eligibility was temporarily restricted in 41 athletes (5.6%). Three athletes (0.4%) had to be excluded from competitive sports. Therapy (eg, physiotherapy, medication) and/or prevention (sensorimotor training, vaccination) recommendations were deduced due to musculoskeletal (t:n = 76,10.3%; p:n = 71,9.8%) and general medicine findings (t:n = 80, 10.9%; p:n = 104, 14.1%).
Conclusion Eligibility for competitive sports is restricted in only 5.5% of adolescent athletes at age 12. Eligibility refusals are rare. However, recommendations for therapy and prevention are frequent, mainly regarding the musculoskeletal system. In spite of time and cost consumption, adolescent preparticipation before entering a career in high-performance sports is supported.
Background: The elderly need strength training more and more as they grow older to stay mobile for their everyday activities. The goal of training is to reduce the loss of muscle mass and the resulting loss of motor function. The dose-response relationship of training intensity to training effect has not yet been fully elucidated.
Methods: PubMed was selectively searched for articles that appeared in the past 5 years about the effects and dose-response relationship of strength training in the elderly.
Results: Strength training in the elderly (> 60 years) increases muscle strength by increasing muscle mass, and by improving the recruitment of motor units, and increasing their firing rate. Muscle mass can be increased through training at an intensity corresponding to 60% to 85% of the individual maximum voluntary strength. Improving the rate of force development requires training at a higher intensity (above 85%), in the elderly just as in younger persons. It is now recommended that healthy old people should train 3 or 4 times weekly for the best results; persons with poor performance at the outset can achieve improvement even with less frequent training. Side effects are rare.
Conclusion: Progressive strength training in the elderly is efficient, even with higher intensities, to reduce sarcopenia, and to retain motor function.
Background Overweight and obesity are increasing health problems that are not restricted to adults only. Childhood obesity is associated with metabolic, psychological and musculoskeletal comorbidities. However, knowledge about the effect of obesity on the foot function across maturation is lacking. Decreased foot function with disproportional loading characteristics is expected for obese children. The aim of this study was to examine foot loading characteristics during gait of normal-weight, overweight and obese children aged 1-12 years. Methods Results Mean walking velocity was 0.95 +/- 0.25 m/s with no differences between normal-weight, overweight or obese children (p = 0.0841). Results show higher foot contact area, arch index, peak pressure and force time integral in overweight and obese children (p< 0.001). Obese children showed the 1.48-fold (1 year-old) to 3.49-fold (10 year-old) midfoot loading (FTI) compared to normal-weight. Conclusion Additional body mass leads to higher overall load, with disproportional impact on the midfoot area and longitudinal foot arch showing characteristic foot loading patterns. Already the feet of one and two year old children are significantly affected. Childhood overweight and obesity is not compensated by the musculoskeletal system. To avoid excessive foot loading with potential risk of discomfort or pain in childhood, prevention strategies should be developed and validated for children with a high body mass index and functional changes in the midfoot area. The presented plantar pressure values could additionally serve as reference data to identify suspicious foot loading patterns in children.
The aim of this study was to acquire static and dynamic foot geometry and loading in childhood, and to establish data for age groups of a population of 1-13 year old infants and children.
A total of 10,382 children were recruited and 7788 children (48% males and 52% females) were finally included into the data analysis. For static foot geometry foot length and foot width were quantified in a standing position. Dynamic foot geometry and loading were assessed during walking on a walkway with self selected speed (Novel Emed X, 100 Hz, 4 sensors/cm(2)). Contact area (CA), peak pressure (PP), force time integral (FTI) and the arch index were calculated for the total, fore-, mid- and hindfoot.
Results show that most static and dynamic foot characteristics change continuously during growth and maturation. Static foot length and width increased with age from 13.1 +/- 0.8 cm (length) and 5.7 +/- 0.4 cm (width) in the youngest to 24.4 +/- 1.5 cm (length) and 8.9 +/- 0.6 cm (width) in the oldest. A mean walking velocity of 0.94 +/- 0.25 m/s was observed. Arch-index ranged from 0.32 +/- 0.04 [a.u.] in the one-year old to 0.21 +/- 0.13 [a.u.] in the 5-year olds and remains constant afterwards.
This study provides data for static and dynamic foot characteristics in children based on a cohort of 7788 subjects. Static and dynamic foot measures change differently during growth and maturation. Dynamic foot measurements provide additional information about the children's foot compared to static measures.
Background
Overweight and obesity are increasing health problems that are not restricted to adults only. Childhood obesity is associated with metabolic, psychological and musculoskeletal comorbidities. However, knowledge about the effect of obesity on the foot function across maturation is lacking. Decreased foot function with disproportional loading characteristics is expected for obese children. The aim of this study was to examine foot loading characteristics during gait of normal-weight, overweight and obese children aged 1-12 years.
Methods
A total of 10382 children aged one to twelve years were enrolled in the study. Finally, 7575 children (m/f: n = 3630/3945; 7.0 +/- 2.9yr; 1.23 +/- 0.19m; 26.6 +/- 10.6kg; BMI: 17.1 +/- 2.4kg/m(2)) were included for (complete case) data analysis. Children were categorized to normalweight (>= 3rd and <90th percentile; n = 6458), overweight (>= 90rd and <97th percentile; n = 746) or obese (>97th percentile; n = 371) according to the German reference system that is based on age and gender-specific body mass indices (BMI). Plantar pressure measurements were assessed during gait on an instrumented walkway. Contact area, arch index (AI), peak pressure (PP) and force time integral (FTI) were calculated for the total, fore-, mid-and hindfoot. Data was analyzed descriptively (mean +/- SD) followed by ANOVA/Welch-test (according to homogeneity of variances: yes/no) for group differences according to BMI categorization (normal-weight, overweight, obesity) and for each age group 1 to 12yrs (post-hoc Tukey Kramer/Dunnett's C; alpha = 0.05).
Results
Mean walking velocity was 0.95 +/- 0.25 m/s with no differences between normal-weight, overweight or obese children (p = 0.0841). Results show higher foot contact area, arch index, peak pressure and force time integral in overweight and obese children (p< 0.001). Obese children showed the 1.48-fold (1 year-old) to 3.49-fold (10 year-old) midfoot loading (FTI) compared to normal-weight.
Conclusion
Additional body mass leads to higher overall load, with disproportional impact on the midfoot area and longitudinal foot arch showing characteristic foot loading patterns. Already the feet of one and two year old children are significantly affected. Childhood overweight and obesity is not compensated by the musculoskeletal system. To avoid excessive foot loading with potential risk of discomfort or pain in childhood, prevention strategies should be developed and validated for children with a high body mass index and functional changes in the midfoot area. The presented plantar pressure values could additionally serve as reference data to identify suspicious foot loading patterns in children.
On utilise de plus en plus les tests de verification pour confirmer l'atteinte du consommation d'oxygene maximale (VO(2 max)). Toutefois, le moment et les methodes d'evaluation varient d'un groupe de travail a l'autre. Les objectifs de cette etude sont de constater si on peut administrer un test de verification apres un test d'effort progressif ou s'il est preferable de le faire une autre journee et si on peut determiner le VO(2 max) tout de meme lors de la premiere seance chez des sujets ne repondant pas au critere de verification. Quarante sujets (age, 24 +/- 4 ans; VO(2 max), 50 +/- 7 mL center dot min(-1)center dot kg(-1)) participent a un test d'effort progressif sur tapis roulant et, 10 min plus tard, a un test de verification (VerifDay1) a 110 % de la velocite maximale (v(max)). Le critere de verification est un VO(2) de pointe au VerifDay1 < 5,5 % a la valeur retenue au test d'effort progressif. Les sujets ne repondant pas au critere de verification passent un autre test de verification, mais a 115 % du VerifDay1', et ce, 10 min plus tard pour confirmer le VO(2) de pointe du VerifDay1 en tant que VO(2 max). Tous les autres sujets repassent le VerifDay1 a un jour different (VerifDay2). Six sujets sur quarante ne repondent pas au critere de verification. Chez quatre d'entre eux, on confirme l'atteinte du VO(2 max) au VerifDay1'. Le VO(2) de pointe au VerifDay1 est equivalent a celui du VerifDay2 (3722 +/- 991 mL center dot min(-1) comparativement a 3752 +/- 995 mL center dot min(-1), p = 0,56), mais le temps jusqu'a l'epuisement est significativement plus long au VerifDay2 (2:06 +/- 0:22 min:s comparativement a 2:42 +/- 0:38 min:s, p < 0,001, n = 34). Le VO(2) de pointe obtenu au test de verification ne semble pas conditionne par un test d'effort progressif maximal prealable. On peut donc realiser le test d'effort progressif et le test de verification lors de la meme seance d'evaluation. Chez presque tous les individus ne repondant pas au critere de verification, on peut determiner le VO(2 max) au moyen d'un autre test de verification plus intense.
Changes in performance parameters over four consecutive maximal incremental cycling tests were investigated to determine how many tests can be performed within one single day without negatively affecting performance. Sixteen male and female subjects (eight trained (T): 25 +/- 3 yr, BMI 22.6 +/- 2.5 kg center dot m(-2), maximal power output (P-max) 4.6 +/- 0.5 W center dot kg(-1); eight untrained (UT): 27 +/- 3 yr, BMI 22.3 +/- 1.2 kg center dot m(-2), P-max 2.9 +/- 0.3 W center dot kg(-1)) performed four successive maximal incremental cycling tests separated by 1.5 h of passive rest. Individual energy requirements were covered by standardised meals between trials. Maximal oxygen uptake (VO2max) remained unchanged over the four tests in both groups (P = 0.20 and P = 0.33, respectively). P-max did not change in the T group (P = 0.32), but decreased from the third test in the UT group (P < 0.01). Heart rate responses to submaximal exercise were elevated from the third test in the T group and from the second test in the UT group (P < 0.05). The increase in blood lactate shifted rightward over the four tests in both groups (P < 0.001 and P < 0.01, respectively). Exercise-induced net increases in epinephrine and norepinephrine were not different between the tests in either group (P 0.15). If VO2max is the main parameter of interest, trained and untrained individuals can perform at least four maximal incremental cycling tests per day. However, because other parameters changed after the first and second test, respectively, no more than one test per day should be performed if parameters other than VO2max are the prime focus.
Background: Exercising at intensities where fat oxidation rates are high has been shown to induce metabolic benefits in recreational and health-oriented sportsmen. The exercise intensity (Fat(peak)) eliciting peak fat oxidation rates is therefore of particular interest when aiming to prescribe exercise for the purpose of fat oxidation and related metabolic effects. Although running and walking are feasible and popular among the target population, no reliable protocols are available to assess Fat(peak) as well as its actual velocity (VPFO) during treadmill ergometry. Our purpose was therefore, to assess the reliability and day-to-day variability of VPFO and Fat(peak) during treadmill ergometry running. Conclusion: In summary, relative and absolute reliability indicators for V-PFO and Fat(peak) were found to be excellent. The observed LoA may now serve as a basis for future training prescriptions, although fat oxidation rates at prolonged exercise bouts at this intensity still need to be investigated.