Voluntary fluid intake, hydration status, and aerobic performance of adolescent athletes in the heat

2010 ◽  
Vol 35 (6) ◽  
pp. 834-841 ◽  
Author(s):  
Boguslaw Wilk ◽  
Brian W. Timmons ◽  
Oded Bar-Or
Keyword(s):  
Body Weight ◽  
Oxygen Uptake ◽  
Exercise Performance ◽  
Fluid Intake ◽  
Tap Water ◽  
Peak Oxygen Uptake ◽  
Adolescent Male ◽  
Aerobic Performance ◽  
Hydration Status ◽  
Time To Exhaustion

We determined whether beverage flavoring and composition would stimulate voluntary drink intake, prevent dehydration, and maintain exercise performance in heat-acclimated adolescent males running in the heat. Eight adolescent (age, 13.7 ± 1.1 years) runners (peak oxygen uptake, 59.5 ± 4.0 mL·kg–1·min–1) underwent at least four 80-min exercise heat-acclimation sessions before completing 3 experimental sessions. All sessions were performed at 30 °C and 60%–65% relative humidity. Each experimental session consisted of five 15-min treadmill runs at a speed eliciting 65% peak oxygen uptake, with a 5 min rest prior to each run. Ten minutes after the final run, a time to exhaustion test was performed at a speed eliciting 90% peak oxygen uptake. Counterbalanced experimental sessions were identical, except for fluid intake, which consisted of tap water (W), flavored water (FW), and FW with 6% carbohydrate and 18 mmol·L–1 NaCl (CNa) consumed ad libitum. Fluid intake and body weight were monitored to calculate dehydration. Voluntary fluid intake was similar to fluid losses in W (1032 ± 130 vs. 1340 ± 246 g), FW (1086 ± 86 vs. 1451 ± 253 g), and CNa (1259 ± 119 vs. 1358 ± 234 g). As a result, significant dehydration was avoided in all trials (–0.45% ± 0.68% body weight in W, –0.66% ± 0.50% body weight in FW, and –0.13% ± 0.71% body weight in CNa). Core temperature increased by ~1 °C during exercise, but was not different between trials. Time to exhaustion was not different between trials and averaged 8.8 ± 1.7 min. Under exercise conditions more closely reflecting real-life situations, heat-acclimatized adolescent male runners can appropriately gauge fluid intake regardless of the type of beverage made available, resulting in consistency in exercise performance.

scholarly journals Physiological responses and cycle characteristics during double-poling versus diagonal-stride roller-skiing in junior cross-country skiers

2021 ◽  
Author(s):  
Erik P. Andersson ◽  
Irina Hämberg ◽  
Paulo Cesar Do Nascimento Salvador ◽  
Kerry McGawley
Keyword(s):  
Oxygen Uptake ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Oxygen Uptake ◽  
Submaximal Exercise ◽  
Rating Of Perceived Exertion ◽  
Time To Exhaustion ◽  
Double Poling ◽  
Cross Country

Abstract Purpose This study aimed to compare physiological factors and cycle characteristics during cross-country (XC) roller-skiing at matched inclines and speeds using the double-poling (DP) and diagonal-stride (DS) sub-techniques in junior female and male XC skiers. Methods Twenty-three well-trained junior XC skiers (11 women, 12 men; age 18.2 ± 1.2 yr.) completed two treadmill roller-skiing tests in a randomized order using either DP or DS. The exercise protocols were identical and included a 5 min warm-up, 4 × 5 min submaximal stages, and an incremental test to exhaustion, all performed at a 5° incline. Results No significant three-way interactions were observed between sex, submaximal exercise intensity, and sub-technique. For the pooled sample, higher values were observed for DP versus DS during submaximal exercise for the mean oxygen uptake kinetics response time (33%), energy cost (18%), heart rate (HR) (9%), blood lactate concentration (5.1 versus 2.1 mmol·L−1), rating of perceived exertion (12%), and cycle rate (25%), while cycle length was lower (19%) (all P < 0.001). During the time-to-exhaustion (TTE) test, peak oxygen uptake ($$\dot{V}$$ V ˙ O2peak), peak HR, and peak oxygen pulse were 8%, 2%, and 6% lower, respectively, for DP than DS, with a 29% shorter TTE during DP (pooled data, all P < 0.001). Conclusion In well-trained junior XC skiers, DP was found to exert a greater physiological load than DS during uphill XC roller-skiing at submaximal intensities. During the TTE test, both female and male athletes were able to ski for longer and reached markedly higher $$\dot{V}$$ V ˙ O2peak values when using DS compared to DP.

scholarly journals Comparison of Aerobic Performance Testing Protocols in Elite Male Wheelchair Basketball Players

2017 ◽  
Vol 60 (1) ◽  
pp. 243-254 ◽  
Author(s):  
Bartosz Molik ◽  
Andrzej Kosmol ◽  
Natalia Morgulec-Adamowicz ◽  
Judit Lencse-Mucha ◽  
Anna Mróz ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Maximal Exercise ◽  
Stress Test ◽  
Lactate Concentration ◽  
Peak Oxygen Uptake ◽  
Aerobic Performance ◽  
Wheelchair Basketball ◽  
Basketball Players ◽  
Wheelchair Sports ◽  
Arm Crank Ergometer

AbstractIn wheelchair sports, aerobic performance is commonly assessed with the use of an arm crank ergometer (ACE), a wheelchair ergometer (WCE) or a wheelchair treadmill (WCT). There are different protocols to identify peak oxygen uptake in wheelchair sports; however, only a few protocols have been applied to evaluate these conditions in wheelchair basketball players. The purpose of this study was to compare physiological responses during maximal exercise testing with the use of ACE and WCT in wheelchair basketball players. Twelve elite male wheelchair basketball players participated in this study. The research was performed during a training camp of the Polish National Wheelchair Basketball Team. The study participants were divided into two functional categories: A (players with class 1.0 - 2.5) and B (players with class 3.0 - 4.5). Two main maximal exercise tests, i.e. wheelchair treadmill stress test (WCT test) and arm crank ergometer stress test (ACE test) were used to evaluate aerobic performance of the players. There were no statistically significant differences in aerobic tests between the players from both groups. The comparison of results achieved in two aerobic tests performed on WCT and ACE did not reveal any significant differences between the analyzed variables (peak heart rate (HRpeak), peak oxygen uptake (VO2peak), minute ventilation (VE), anaerobic threshold (AT), lactate concentration (LApeak), and a drop in lactate concentration (%LA)). Strong correlations between results achieved in WCT and ACE tests were found for VO2peak, VE and LApeak. The main conclusion of the study is that both WCT and ACE tests may be useful when determining aerobic capacity of wheelchair basketball players. Moreover, both protocols can be used by athletes regardless of their functional capabilities and types of impairment.

Metabolic Profiles of the 30-15 Intermittent Fitness Test and the Corresponding Continuous Version in Team-Sport Athletes—Elucidating the Role of Inter-Effort Recovery

2020 ◽  
pp. 1-6
Author(s):  
Sebastian Kaufmann ◽  
Ralph Beneke ◽  
Richard Latzel ◽  
Hanna Pfister ◽  
Olaf Hoos
Keyword(s):  
Oxygen Uptake ◽  
State Level ◽  
Peak Oxygen Uptake ◽  
Metabolic Energy ◽  
Time To Exhaustion ◽  
Metabolic Profiles ◽  
Energy Contribution ◽  
Continuous Version ◽  
Fitness Test

Purpose: To elucidate the role of inter-effort recovery in shuttle running by comparing the metabolic profiles of the 30-15 Intermittent Fitness Test (30-15IFT) and the corresponding continuous version (30-15IFT-CONT). Methods: Sixteen state-level handball players (age = 23 [3] y, height = 185 [7] cm, weight = 85 [14] kg) completed the 30-15IFT and 30-15IFT-CONT, and speed at the last completed stage (in kilometers per hour) and time to exhaustion (in seconds) were assessed. Furthermore, oxygen uptake (in milliliters per kilogram per minute) and blood lactate were obtained preexercise, during exercise, and until 15 minutes postexercise. Metabolic energy (in kilojoules), metabolic power (in Watts per kilogram), and relative (in percentage) energy contribution of the aerobic (WAER, WAERint), anaerobic lactic (WBLC, WBLCint), and anaerobic alactic (WPCr, WPCrint) systems were calculated by PCr-La-O2 method for 30-15IFT-CONT and 30-15IFT. Results: No difference in peak oxygen uptake was found between 30-15IFT and 30-15IFT-CONT (60.6 [6.6] vs 60.5 [5.1] mL·kg−1·min−1, P = .165, d = 0.20), whereas speed at the last completed stage was higher in 30-15IFT (18.3 [1.4] vs 16.1 [1.0] km·h−1, P < .001, d = 1.17). Metabolic energy was also higher in 30-15IFT (1224.2 [269.6] vs 772.8 [63.1] kJ, P < .001, d = 5.60), and metabolic profiles differed substantially for aerobic (30-15IFT = 67.2 [5.2] vs 30-15IFT-CONT = 85.2% [2.5%], P < .001, d = −4.01), anaerobic lactic (30-15IFT = 4.4 [1.4] vs 30-15IFT-CONT = 6.2% [1.8%], P < .001, d = −1.04), and anaerobic alactic (30-15IFT = 28.4 [4.7] vs 30-15IFT-CONT = 8.6% [2.1%], P < .001, d = 5.43) components. Conclusions: Both 30-15IFT and 30-15IFT-CONT are mainly fueled by aerobic energy, but their metabolic profiles differ substantially in both aerobic and anaerobic alactic energy contribution. Due to the presence of inter-effort recovery, intermittent shuttle runs rely to a higher extent on anaerobic alactic energy and a fast, aerobic replenishment of PCr during the short breaks between shuttles.

Niacin supplementation impairs exercise performance

2021 ◽  
Author(s):  
Greggory R. Davis ◽  
Arnold G. Nelson
Keyword(s):  
Body Weight ◽  
Resistance Exercise ◽  
Aerobic Exercise ◽  
Exercise Performance ◽  
Respiratory Exchange Ratio ◽  
Time To Exhaustion ◽  
Total Work ◽  
Cycling Exercise ◽  
Exercise Time ◽  
Performance Effects

Abstract. Several pre-workout supplements contain niacin, although the exercise performance effects of niacin are poorly understood. The purpose of the present study was to examine the performance effects of niacin versus caffeine as a pre-workout supplement. Twenty-five untrained males were recruited to complete three identical ramped aerobic cycling exercise trials. Participants were administered caffeine (CA) at 5 mg/kg body weight, 1000 mg niacin (NI), or a methylcelluloce placebo (PL) supplement prior to each trial. NI treatment induced significantly higher respiratory exchange ratio (RER) during exercise compared to the CA treatment, but not the PL treatment (PL=0.87±0.08, NI=0.91±0.08, CA=0.87±0.08; p=0.02). Similarly, exercise time to exhaustion (in minutes) was significantly different between the NI treatment and the CA treatment, but not the PL treatment (PL=27.45±4.47, NI=26.30±4.91, CA=28.76±4.86; p<0.01). Habitual caffeine use (p=0.16), habitual aerobic exercise (p=0.60), and habitual resistance exercise (p=0.10) did not significantly affect RER. Similarly, habitual caffeine use (p=0.72), habitual aerobic exercise (p=0.08), and habitual resistance exercise (p=0.39) did not significantly affect total work performed. The elevated RER and decreased time to exhaustion in the NI treatment suggests limited lipid availability during exercise and impaired exercise performance.

The Influence of Heat Acclimation and Hypohydration on Post-Weight-Loss Exercise Performance

2020 ◽  
Vol 15 (2) ◽  
pp. 213-221
Author(s):  
Oliver R. Barley ◽  
Dale W. Chapman ◽  
Georgios Mavropalias ◽  
Chris R. Abbiss
Keyword(s):  
Body Mass ◽  
Exercise Performance ◽  
Fluid Intake ◽  
Heat Acclimation ◽  
Hydration Status ◽  
Performance Variables ◽  
Pooled Data ◽  
Ad Libitum ◽  
Experimental Trials ◽  
Food And Fluid Intake

Purpose: To examine the influence of fluid intake on heat acclimation and the subsequent effects on exercise performance following acute hypohydration. Methods: Participants were randomly assigned to 1 of 2 groups, either able to consume water ad libitum (n = 10; age 23 [3] y, height 1.81 [0.09] m, body mass 87 [13] kg; HAW) or not allowed fluid (n = 10; age 26 [5] y, height 1.76 [0.05] m, body mass 79 [10] kg; HANW) throughout 12 × 1.5-h passive heat-acclimation sessions. Experimental trials were completed on 2 occasions before (2 baseline trials) and 1 following the heat-acclimation sessions. These sessions involved 3 h of passive heating (45°C, 38% relative humidity) to induce hypohydration followed by 3 h of ad libitum food and fluid intake after which participants performed a repeat sled-push test to assess physical performance. Urine and blood samples were collected before, immediately, and 3 h following hypohydration to assess hydration status. Mood was also assessed at the same time points. Results: No meaningful differences in physiological or performance variables were observed between HANW and HAW at any time point. Using pooled data, mean sprint speed was significantly (P < .001) faster following heat acclimation (4.6 [0.7] s compared with 5.1 [0.8] s). Furthermore, heat acclimation appeared to improve mood following hypohydration. Conclusions: Results suggest that passive heat-acclimation protocols may be effective at improving short-duration repeat-effort performance following acute hypohydration.

scholarly journals Effects of Ramadan Fasting on Body Composition, Aerobic Performance and Lactate, Heart Rate and Perceptual Responses in Young Soccer Players

2011 ◽  
Vol 29 (1) ◽  
pp. 79-91 ◽  
Author(s):  
Alpay Güvenç
Keyword(s):  
Heart Rate ◽  
Body Composition ◽  
Aerobic Exercise ◽  
Blood Lactate ◽  
Exercise Performance ◽  
Perceived Exertion ◽  
Soccer Players ◽  
Aerobic Performance ◽  
Hydration Status ◽  
Ramadan Fasting

Effects of Ramadan Fasting on Body Composition, Aerobic Performance and Lactate, Heart Rate and Perceptual Responses in Young Soccer PlayersThe purpose of this study was to examine the effects of Ramadan fasting on body composition, aerobic exercise performance and blood lactate, heart rate and perceived exertion in regularly trained young soccer players. Sixteen male soccer players participated in this study. Mean age, stature, body mass and training age of the players were 17.4±1.2 years, 175.4±3.6 cm, 69.6±4.3 kg and 5.1±1.3 years, respectively. During the Ramadan period, all subjects voluntarily chose to follow the fasting guidelines and abstained from eating and drinking from sunrise to sunset. Body composition, hydration status, dietary intake and sleep duration were assessed on four occasions: before Ramadan, at the beginning of Ramadan, at the end of Ramadan and 2 weeks after the end of Ramadan. On each occasion, aerobic exercise performance and blood lactate, heart rate and rating of perceived exertion responses of players were also determined during an incremental running test. Repeated measures of ANOVA revealed that body mass, percentage of body fat, fat-free mass, hydration status, daily sleeping time and daily energy and macronutrient intake of players did not vary significantly throughout the study period (p>0.05). However, players experienced a small but significant decrease in skinfold thicknesses over the course of the study (p<0.05). Although ratings of perceived exertion at submaximal workloads increased during Ramadan (p<0.05), blood lactate and heart rate responses had decreased by the end of Ramadan (p<0.05). In line with these changes, peak running performance and running velocity at anaerobic threshold also improved by the end of Ramadan (p<0.05). Improvements in aerobic exercise performance with time were probably due to the effects of pre-season training program that was performed after the break of the fast (Iftar) during the month of Ramadan. The results of the present study suggest that if regular training regimen, body fluid balance, daily energy intake and sleep duration are maintained as before Ramadan, Ramadan fasting does not have detrimental effects on aerobic exercise performance or body composition in young soccer players.

Acute Cardiometabolic and Perceptual Responses to Individual and Group-Based Body-Weight Resistance Exercise in Girls

2021 ◽  
pp. 1-10
Author(s):  
Jeanette M. Ricci ◽  
Katharine D. Currie ◽  
Todd A. Astorino ◽  
Karin A. Pfeiffer
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Oxygen Uptake ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Oxygen Uptake ◽  
Acute Responses ◽  
Maximal Aerobic Speed ◽  
The Mean

Girls’ acute responses to group-based high-intensity interval exercise (HIIE) are not well characterized. Purpose: To compare acute responses to treadmill-based HIIE (TM) and body-weight resistance exercise circuit (CIRC) and to CIRC performed in a small-group setting (group CIRC). Method: Nineteen girls (9.1 [1.1] y) completed exercise testing on a TM to determine peak oxygen uptake, peak heart rate (HRpeak), and maximal aerobic speed. The TM involved eight 30-second sprints at 100% maximal aerobic speed. The CIRC consisted of 8 exercises of maximal repetitions performed for 30 seconds. Each exercise bout was followed by 30 seconds of active recovery. The blood lactate concentration was assessed preexercise and postexercise. The ratings of perceived exertion, affective valence, and enjoyment were recorded at preexercise, Intervals 3 and 6, and postexercise. Results: The mean heart rate was higher during group CIRC (92% [7%] HRpeak) than CIRC (86% [7%] HRpeak) and TM (85% [4%] HRpeak) ( = .49). The mean oxygen uptake equaled 76% (11%) of the peak oxygen uptake for CIRC and did not differ from TM (d = 0.02). The CIRC elicited a greater postexercise blood lactate concentration versus TM (5.8 [1.7] vs 1.4 [0.4] mM, d = 3.61). The perceptual responses were similar among conditions (P > .05), and only the rating of perceived exertion increased during exercise ( = .78). Conclusion: Whether performed individually or in a small group, CIRC represents HIIE and may be a feasible alternative to running-based HIIE.

Muscle-specific expression of PPARγ coactivator-1α improves exercise performance and increases peak oxygen uptake

2008 ◽  
Vol 104 (5) ◽  
pp. 1304-1312 ◽  
Author(s):  
Jennifer A. Calvo ◽  
Thomas G. Daniels ◽  
Xiaomei Wang ◽  
Angelika Paul ◽  
Jiandie Lin ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Exercise Performance ◽  
Mitochondrial Gene ◽  
Oxidative Capacity ◽  
Peak Oxygen Uptake ◽  
Whole Body ◽  
Peroxisome Proliferator ◽  
Sprint Training ◽  
Specific Expression

The induction of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a key regulator of mitochondriogenesis, is well-established under multiple physical exercise regimens, including, endurance, resistance, and sprint training. We wanted to determine if increased expression of PGC-1α in muscle is sufficient to improve performance during exercise in vivo. We demonstrate that muscle-specific expression of PGC-1α improves the performance during voluntary as well as forced exercise challenges. Additionally, PGC-1α transgenic mice exhibit an enhanced performance during a peak oxygen uptake exercise test, demonstrating an increased peak oxidative capacity, or whole body oxygen uptake. This increased ability to perform in multiple exercise paradigms is supported by enhanced mitochondrial function as suggested by increased mitochondrial gene expression, mitochondrial DNA, and mitochondrial enzyme activity. Thus this study demonstrates that upregulation of PGC-1α in muscle in vivo is sufficient to greatly improve exercise performance under various exercise paradigms as well as increase peak oxygen uptake.

Critical power in adolescent boys and girls — an exploratory study

2008 ◽  
Vol 33 (6) ◽  
pp. 1105-1111 ◽  
Author(s):  
Craig A. Williams ◽  
Jeanne Dekerle ◽  
Kerry McGawley ◽  
Serge Berthoin ◽  
Helen Carter
Keyword(s):  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Critical Power ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Random Order ◽  
Constant Load ◽  
Peak Oxygen Uptake ◽  
Time To Exhaustion ◽  
Intensity Of Exercise

The purpose of the study was to identify critical power (CP) in boys and girls and to examine the physiological responses to exercise at and 10% above CP (CP+10%) in a sub-group of boys. Nine boys and 9 girls (mean age 12.3 (0.5) y performed 3 constant-load tests to derive CP. Eight of the boys then exercised, in random order, at CP and CP+10% until volitional exhaustion. CP was 123 (28) and 91 (26) W for boys and girls, respectively (p < 0.02), which was equivalent to 75 (6) and 72 (10) % of peak oxygen uptake, respectively (p > 0.47). Boys’ time to exhaustion at CP was 18 min 37 s (4 min 13 s), which was significantly longer (p < 0.007) than that at CP+10% (9 min 42 s (2 min 31 s)). End-exercise values for blood lactate concentration (B[La]) and maximal oxygen uptake were higher in the CP+10% trial (5.0 (2.4) mmol·L–1 and 2.15 (0.4) L·min–1, respectively) than in the CP trial, (B[La], 4.7 (2.1) mmol·L–1; maximal oxygen uptake, 2.05 (0.35) L·min–1; p > 0.13). Peak oxygen uptake (expressed as a percentage of the peak value) was not attained at the end of the trials (94 (12) and 98 (14) % for CP and CP+10%, respectively). These results provide information about the boundary between the heavy and severe exercise intensity domains in children, and have demonstrated that CP in a group of boys does not represent a sustainable steady-state intensity of exercise.

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