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Bentley, David J.; Ackerman, James; McNaughton, Lars R. FACSM; Trapp, E Gayle
1Adelaide University, Adelaide, Australia. 2University of NSW, Sydney, Australia. 3Bond University, Gold Coast, Australia.
(No relationships reported)
Free radical production during exercise has been implicated as part of the process of muscular fatigue. Antioxidant (AOX) supplementation has been shown to be effective in improving performance during endurance exercise. However the effects of AOX supplementation on resistance training (RT) performance has not been widely studied. Pycnogenol is the registered trade name for a natural (Pine bark) extract containing a combination of phenolic acids, catechin, taxifolin and procyanidins. Pycnogenol exerts pronounced AOX effects in vitro but have not been examined for its potential ergogenic effects.
PURPOSE: to determine whether acute AOX supplementation (Lactaway ©), containing Pycnogenol, will attenuate fatigue during resistance training (RT) and if this effect is associated with alteration of free radical activity or changes in endocrine responses.
METHODS: Fifteen RT trained males (23+4 yrs) participated in a double blind crossover experiment. The subjects completed a single exercise task [back squats; 70% one repetition maximum load (RM); ten repetitions for six sets] on two occasions. Subjects consumed a supplement or placebo four hours prior to each task. Subjects were instructed to perform the concentric phase of the exercise task in as short as time as possible. Venous blood was withdrawn pre, immediately post and 20 min post exercise. Barbell velocity and power was measured through the Gymaware optical encoder.
RESULTS: Total power production during the AOX trial was significantly higher than during the placebo trial (6746+5.9 vs. 6493+17.1, W, p=<0.002). Xanthine oxidase (XO) concentration was lower after the RT when the supplement was ingested (11.2+2.48 vs. 15.4+1.11 mU/ml, p=.0.069). Growth Hormone (GH) levels were also attenuated immediately after the AOX RT trial compared to the placebo trial (6.65+1.84 vs. 16.08+ 2.78, ng/ml, p=<0.0001). Cortisol levels increased significantly after exercise but there was no significant difference between conditions (567+20 vs. 571+18 nmol/L).
CONCLUSION: The ergogenic properties of the AOX supplement do not appear to be mediated through altering free radical activity. Whilst further analysis is required it appears that the AOX supplement is bioavailable and associated with fatigue resistance during high intensity resistance type exercise.
© 2011 American College of Sports Medicine
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