The Acute Effects of Androstenedione Supplementation in Healthy Young Males

2000 ◽  
Vol 25 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Craig S. Ballantyne ◽  
Stuart M. Phillips ◽  
Jay R. Macdonald ◽  
Mark A. Tarnopolsky ◽  
J. Duncan Macdougall
Keyword(s):  
Luteinizing Hormone ◽  
Resistance Exercise ◽  
Elevated Plasma ◽  
Acute Effects ◽  
Double Blind ◽  
Male Athletes ◽  
Young Males ◽  
Plasma Estradiol ◽  
Key Words Testosterone ◽  
Heavy Resistance Exercise

We examined the effects of androstenedione supplementation on the hormonal profile of 10 males and its interaction with resistance exercise. Baseline testosterone, luteinizing hormone, estradiol, and androstenedione concentrations were established by venous sampling at 3 hr intervals over 24 hr. Subjects ingested 200 mg of androstenedione daily for 2 days, with second and third day blood samples. Two weeks later, they ingested androstenedione or a placebo for 2 days, in a double-blind, cross-over design. On day 2, they performed heavy resistance exercise with blood sampled before, after, and 90 min post. The supplement elevated plasma androstenedione 2-3-fold and luteinizing hormone ∼70% but did not alter testosterone concentration. Exercise elevated testosterone, with no difference between conditions. Exercise in the supplemented condition significantly elevated plasma estradiol by ∼83% for 90 min. Androstenedione supplementation, thus, is unlikely to provide male athletes with any anabolic benefit and, with heavy resistance exercise, elevates estrogen. Key Words: testosterone, luteinizing hormone, estradiol, fluid shifts, resistance exercise

scholarly journals Mechanical Analysis of the Acute Effects of a Heavy Resistance Exercise Warm-Up on Agility Performance in Court-Sport Athletes

2013 ◽  
Vol 39 (1) ◽  
pp. 147-156 ◽  
Author(s):  
Christopher J. Sole ◽  
Gavin L. Moir ◽  
Shala E. Davis ◽  
Chad A. Witmer
Keyword(s):  
Resistance Exercise ◽  
Body Mass ◽  
Reaction Force ◽  
Body Height ◽  
Stride Frequency ◽  
Camera Motion ◽  
Acute Effects ◽  
Training Experience ◽  
Warm Up ◽  
Heavy Resistance Exercise

Abstract The purpose of this study was to determine the acute effects of heavy resistance exercise on agility performance in court-sport athletes. Five men (age: 20.6 ± 1.9 years; body mass: 79.36 ± 11.74 kg; body height: 1.93 ± 0.09 m) and five women (age 21.2 ± 2.7 years; body mass: 65.8 ± 10.18 kg; body height 1.77 ± 0.08 m) volunteered to participate in the present study. All subjects were NCAA Division II athletes who currently participated in tennis or basketball and all had previous resistance training experience of at least one year. In a counterbalanced design, agility performance during a 10 m shuttle test was assessed following either a dynamic warm-up (DW) or heavy resistance warm-up (HRW) protocol. The HRW protocol consisted of three sets of squats at 50, 60, and 90% of 1-RM. Agility performance was captured using an eight camera motion analysis system and the mechanical variables of stride length, stride frequency, stance time, flight time, average ground reaction force, as well as agility time were recorded. No significant differences were reported for the HRW and DW protocols for any of the mechanical variables (p>0.05), although there was a trend towards the HRW protocol producing faster agility times compared to the control protocol (p = 0.074). Based on the trend towards a significant effect, as well as individual results it is possible that HRW protocols could be used as an acute method to improve agility performance in some court-sport athletes.

Changes in Hormonal Concentrations after Different Heavy-Resistance Exercise Protocols in Women

1993 ◽  
Author(s):  
William J. Kraemer ◽  
Steven J. Fleck ◽  
Joseph E. Dziados ◽  
Everett A. Harman ◽  
Louis J. Marchitelli
Keyword(s):  
Resistance Exercise ◽  
Heavy Resistance Exercise

scholarly journals Acute effects of dapagliflozin on renal oxygenation and perfusion in type 1 diabetes with albuminuria: A randomised, double-blind, placebo-controlled crossover trial

2021 ◽  
pp. 100895
Author(s):  
Jens Christian Laursen ◽  
Niels Søndergaard-Heinrich ◽  
Joana Mendes Lopes de Melo ◽  
Bryan Haddock ◽  
Ida Kirstine Bull Rasmussen ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Crossover Trial ◽  
Acute Effects ◽  
Double Blind ◽  
Double Blind Placebo

scholarly journals Does variation in trait schizotypy and frequency of cannabis use influence the acute subjective, cognitive and psychotomimetic effects of delta-9-tetrahydrocannabinol? A mega-analysis

2021 ◽  
pp. 026988112095960
Author(s):  
Abigail M Freeman ◽  
Claire Mokrysz ◽  
Chandni Hindocha ◽  
Will Lawn ◽  
Celia JA Morgan ◽  
...  
Keyword(s):  
Personality Traits ◽  
Memory Impairment ◽  
Linear Models ◽  
Cannabis Use ◽  
Acute Effects ◽  
Double Blind ◽  
Schizotypal Personality ◽  
Domain Specific ◽  
Individual Participant ◽  
Psychotomimetic Effects

Background: While the acute effects of cannabis are relatively benign for most users, some individuals experience significant adverse effects. This study aimed to identify whether variation in schizotypal personality traits and frequency of cannabis use influence the acute effects of delta-9-tetrahydrocannabinol (THC). Methods: Individual participant data from four double-blind, randomised, placebo-controlled, acute crossover studies involving 128 cannabis users were combined for a mega-analysis. Using multilevel linear models and moderation analyses, frequency of cannabis use and schizotypal personality traits were investigated as potential moderators of the subjective, cognitive and psychotomimetic effects of acute THC. Results: There was evidence of a moderating effect where increased frequency of cannabis use was associated with reduced intensity of subjective (changes in alertness and feeling stoned) and psychosis-like effects following THC when compared with placebo. Moderating effects of cannabis use frequency on acute memory impairment were weak. Trait schizotypy did not moderate the acute psychosis-like effects of THC compared with placebo. Conclusions: Our results suggest that a pattern of domain-specific tolerance develops to the acute effects of THC. Tolerance to the alertness-reducing effects occurred more readily than tolerance to psychotomimetic effects. Only partial tolerance to feeling stoned was found, and there was weak evidence for tolerance to memory impairment. Trait schizotypy did not moderate THC’s effects on psychotomimetic symptoms.

scholarly journals Does Consumption of Nitrate Containing Beetroot Juice Affect Indoor Rowing Performance in Males and Females?

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1754-1754
Author(s):  
Giselle Greisman ◽  
June Kloubec ◽  
Alexandra Kazaks ◽  
Kelly Morrow ◽  
Cristen Harris
Keyword(s):  
P Value ◽  
Beetroot Juice ◽  
Double Blind ◽  
Male Athletes ◽  
Funding Sources ◽  
Beverage Type ◽  
Rowing Performance ◽  
Males And Females ◽  
The Difference ◽  
Research Grant

Abstract Objectives The nitrates found in beetroot juice (BR) are known to be a precursor of nitric oxide (NO). NO is a known vasodilator which allows more oxygen to travel in the blood and may improve muscle efficiency. This study aims to measure the effect of BR supplementation on performance on 500-meter row time for trained CrossFit athletes. Many past studies have analyzed the effect of BR on male athletes, this study aimed to include both males and females. Methods This study used a randomized, cross-over, double-blind, placebo-controlled design to measure 500-meter row time. Thirty athletes age 18–60 consumed either a 2.7 oz shot of BR (6.5 mmol nitrate) or a placebo nitrate-free beetroot juice (PL). Two hours later, they rowed 500 meters. After at least a seven-day washout period, athletes repeated the 500-meter row with either BR or PL for comparison. This study was performed from July 2019 – January 2020 and was conducted in Mercer Island, Washington. Results Ten males age 18.0 to 60.3 (median 47.7) and twenty females age 26.7 to 58.3 (median 43.8), participated in this study. Row times for the 500-meter row ranged from 88.2 seconds to 150.7 seconds. Data indicate that although 60% of all participants rowed faster with BR (mean 112.83 seconds), compared to PL (mean 113.40 seconds), the difference in the means of row times (−0.563) was not significant overall (P = 0.29). However, for the 10 males, row times were significantly faster (1.02 second difference, P = 0.04) on average with BR compared to PL. For the 20 females, the difference in mean row time (−0.335 seconds) was not significant (P = 0.66). Competitive rowers were defined as those who rowed under 110 seconds (N = 15). For competitive rowers (10 males, 5 females), row times were significantly faster with BR compared to PL (difference in means −0.94, P = 0.009). However, for those rowers, the P-value of drink * group was 0.015. Conclusions Dietary nitrate improved indoor rowing performance in males but not in females. In addition, competitive rowers were also significantly faster with BR, however, there may be an order bias, since there was significant interaction between beverage type and testing order. Food based nitrate supplements may increase rowing performance with male rowers. Funding Sources Supported by Bastyr Faculty Student Research Grant.

scholarly journals Acute effects of a commercially-available pre-workout supplement on markers of training: a double-blind study

2014 ◽  
Vol 11 (1) ◽  
Author(s):  
Jordan J Outlaw ◽  
Colin D Wilborn ◽  
Abbie E Smith-Ryan ◽  
Sara E Hayward ◽  
Stacie L Urbina ◽  
...  
Keyword(s):  
Blind Study ◽  
Double Blind Study ◽  
Acute Effects ◽  
Double Blind
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