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Daniele Magistro, Filippo Candela, Paolo Riccardo Brustio, Monica Emma Liubicich and Emanuela Rabaglietti

Functional aging processes are characterized by a loss of performance capabilities for most physiological systems, such as aerobic endurance and lower body strength, which are important for independent living and active aging. The present study examines the direction of influence between aerobic endurance and lower body strength over time in Italian sedentary older adults. A three-wave longitudinal model was tested using cross-lagged analysis for 202 individuals aged over 65 years (mean = 73.92, SD = 5.84; 140 females). Analysis revealed that aerobic endurance and lower body strength decline over time. In addition, greater aerobic endurance positively affected lower body strength over time; however, the converse was true only during the first period (first 6 months). These findings emphasize the importance of these relationships for the design and implementation of effective physical intervention for older adults.

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Daniel Bok and Igor Jukić

significant relationships between v2 and total distance: individualized training impulse (iTRIMP) ratio ( r  = .69) and high-intensity distance:iTRIMP ratio ( r  = .58, P  = .08), respectively, were recorded during soccer simulation test. 37 It seems to be that greater aerobic endurance presents a fitness

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Erin E. Sutton, M. Regina Coll and Patricia A. Deuster

Acute tyrosine ingestion is thought to improve aerobic endurance, muscle strength and endurance, and anaerobic power of men undergoing severe physiologic stress. In a double-blind, crossover study, 20 men (32 ± 1 y old) underwent 2 loadcarriage treadmill sessions, 1 after taking tyrosine (150 mg/kg L-crystalline tyrosine) and 1 after taking placebo. Tyrosine dosage was based on subject weight and ingested 30 min before load carriage. A physical performance battery was administered after the load carriage: maximal and submaximal handgrip, pull-ups, and stair stepping with weight. Total time on treadmill was not significantly lengthened with ingestion of tyrosine (118.9 ± 1.4 min) as compared with placebo (119.2 ± 1.2 min). Total power for stair stepping (tyrosine 223 ± 8 watts, placebo 216 ± 9 watts) and muscle strength and endurance (handgrip) was not significantly improved by tyrosine ingestion. The results indicate that acute ingestion of tyrosine by healthy men has no measurable effect on endurance, muscle strength, or anaerobic power.

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Lars Donath, Lukas Zahner, Mareike Cordes, Henner Hanssen, Arno Schmidt-Trucksäss and Oliver Faude

The study investigated physiological responses during 2-km walking at a certain intensity of a previously performed maximal exercise test where moderate perceived exertion was reported. Twenty seniors were examined by an incremental walking treadmill test to obtain maximal oxygen uptake (VO2max). A submaximal 2-km walking test was applied 1 wk later. The corresponding moderate perceived exertion (4 on the CR-10 scale) during the VO2max test was applied to the 2-km treadmill test. Moderate exertion (mean rating of perceived exertion [RPE]: 4 ± 1) led to 76% ± 8% of VO2max and 79% ± 6% of maximal heart rate. RPE values drifted with a significant time effect (p = .001, ηp = .58) during the 2-km test from 3 ± 0.7 to 4.6 ± 0.8. Total energy expenditure (EE) was 3.3 ± 0.5 kcal/kg. No gender differences in ventilatory, heart-rate, or EE data occurred. Brisk walking at moderate RPE of 3–5 would lead to a beneficial physiological response during endurance training and a weekly EE of nearly 1,200 kcal when exercising 5 times/wk for 30 min.

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John L. Ivy, Lynne Kammer, Zhenping Ding, Bei Wang, Jeffrey R. Bernard, Yi-Hung Liao and Jungyun Hwang

Context:

Not all athletic competitions lend themselves to supplementation during the actual event, underscoring the importance of preexercise supplementation to extend endurance and improve exercise performance. Energy drinks are composed of ingredients that have been found to increase endurance and improve physical performance.

Purpose:

The purpose of the study was to investigate the effects of a commercially available energy drink, ingested before exercise, on endurance performance.

Methods:

The study was a double-blind, randomized, crossover design. After a 12-hr fast, 6 male and 6 female trained cyclists (mean age 27.3 ± 1.7 yr, mass 68.9 ± 3.2 kg, and VO2 54.9 ± 2.3 ml · kg–1 · min–1) consumed 500 ml of either flavored placebo or Red Bull Energy Drink (ED; 2.0 g taurine, 1.2 g glucuronolactone, 160 mg caffeine, 54 g carbohydrate, 40 mg niacin, 10 mg pantothenic acid, 10 mg vitamin B6, and 10 μg vitamin B12) 40 min before a simulated cycling time trial. Performance was measured as time to complete a standardized amount of work equal to 1 hr of cycling at 70% Wmax.

Results:

Performance improved with ED compared with placebo (3,690 ± 64 s vs. 3,874 ± 93 s, p < .01), but there was no difference in rating of perceived exertion between treatments. β-Endorphin levels increased during exercise, with the increase for ED approaching significance over placebo (p = .10). Substrate utilization, as measured by open-circuit spirometry, did not differ between treatments.

Conclusion:

These results demonstrate that consuming a commercially available ED before exercise can improve endurance performance and that this improvement might be in part the result of increased effort without a concomitant increase in perceived exertion.

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Peter Le Rossignol, Tim J. Gabbett, Dan Comerford and Warren R. Stanton

Purpose:

To investigate the relationship between selected physical capacities and repeated-sprint performance of Australian Football League (AFL) players and to determine which physical capacities contributed to being selected for the first competition game.

Methods:

Sum of skinfolds, 40-m sprint (with 10-, 20-, 30-, and 40-m splits), repeated-sprint ability (6 × 30-m sprints), and 3-km-run time were measured during the preseason in 20 AFL players. The physical qualities of players selected to play the first match of the season and those not selected were compared. Pearson correlation coefficients were used to determine the relationship among variables, and a regression analysis identified variables significantly related to repeated-sprint performance.

Results:

In the regression analysis, maximum velocity was the best predictor of repeated-sprint time, with 3-km-run time also contributing significantly to the predictive model. Sum of skinfolds was significantly correlated with 10-m (r = .61, P < .01) and 30-m (r = .53, P < .05) sprint times. A 2.6% ± 2.1% difference in repeated-sprint time (P < .05, ES = 0.88 ± 0.72) was observed between those selected (25.26 ± 0.55 s) and not selected (25.82 ± 0.80 s) for the first game of the season.

Conclusions:

The findings indicate that maximum-velocity training using intervals of 30–40 m may contribute more to improving repeated-sprint performance in AFL players than short 10- to 20-m intervals from standing starts. Further research is warranted to establish the relative importance of endurance training for improving repeated-sprint performance in AFL football.

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Vanessa Martínez-Lagunas and Ulrich Hartmann

Purpose:

To evaluate the validity of the Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) for the direct assessment and the indirect estimation of maximal oxygen consumption (VO2max) in female soccer players compared with a maximal laboratory treadmill test (LTT).

Methods:

Eighteen female soccer players (21.5 ± 3.4 y, 165.6 ± 7.5 cm, 63.3 ± 7.4 kg; mean ± SD) completed an LTT and a YYIR1 in random order (1 wk apart). Their VO2max was directly measured via portable spirometry during both tests and indirectly estimated from a published non-gender-specific formula (YYIR1-F1).

Results:

The measured VO2max values in LTT and YYIR1 were 55.0 ± 5.3 and 49.9 ± 4.9 mL · kg−1 · min−1, respectively, while the estimated VO2max values from YYIR1-F1 corresponded to 45.2 ± 3.4 mL · kg−1 · min−1. Large positive correlations between the VO2max values from YYIR1 and LTT (r = .83, P < .001, 90% confidence interval = .64–.92) and YYIR1-F1 and LTT (r = .67, P = .002, .37–.84) were found. However, the YYIR1 significantly underestimated players’ VO2max by 9.4% compared with LTT (P < .001) with Bland-Altman 95% limits of agreement ranging from –20.0% to 1.4%. A significant underestimation from the YYIR1-F1 (P < .001) was also identified (17.8% with Bland-Altman 95% limits of agreement ranging from –31.8% to –3.8%).

Conclusions:

The YYIR1 and YYIR1-F1 are not accurate methods for the direct assessment or indirect estimation of VO2max in female soccer players. The YYIR1-F1 lacks gender specificity, which might have been the reason for its larger error.

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Daniel G. Syrotuik, Kirsten L. MacFadyen, Vicki J. Harber and Gordon J. Bell

To examine the effects of elk velvet antler supplementation (EVA) combined with training on resting and exercise-stimulated hormonal response, male (n = 25) and female (n = 21) rowers ingested either E VA (560 mg/d) or placebo (PL) during 10 wk of training. VO2max, 2000 m rowing time, leg and bench press strength were determined before and after 5 and 10 wk of training. Serum hormone levels were measured prior to and 5 and 60 min after a simulated 2000 m rowing race. VO2max and strength increased and 2000 m times decreased similarly (P < 0.05) with training. There was no significant difference between the EVA and PL group for any hormonal response. Testosterone (males only) and growth hormone (both genders) were higher 5 min after the simulated race (P < 0.05) but returned to baseline at 60 min. Cortisol was higher 5 and 60 min compared to rest (both genders) (P < 0.05) and was higher 60 min post-exercise following 5 and 10 wk of training. It appears that 10 wk of EVA supplementation does not significantly improve rowing performance nor alter hormonal responses at rest or after acute exercise than training alone.

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Robert MacKenzie, Linda Monaghan, Robert A. Masson, Alice K. Werner, Tansinee S. Caprez, Lynsey Johnston and Ole J. Kemi

), including after normalization to body weight (Figure  2D inset), However, upper-arm biceps strength showed a trend toward statistical significance to climbing ability (Figure  2B ), including after normalization to body weight (Figure  2B inset: P  = .08). Aerobic Endurance Aerobic endurance capacity in

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Cheryl Der Ananian, Renae Smith-Ray, Brad Meacham, Amy Shah and Susan Hughes

! in Hispanics with arthritis. The assessment of feasibility included an evaluation of the effectiveness of ¡En Forma y Fuerte! on lower-extremity strength, aerobic endurance, and perceived physical function, pain, and stiffness in Hispanics with lower extremity arthritis; an assessment of