Journal of Strength and Conditioning Research, 2011
Rahimi, R. Creatine supplementation decreases oxidative DNA damage and lipid peroxidation induced... more Rahimi, R. Creatine supplementation decreases oxidative DNA damage and lipid peroxidation induced by a single bout of resistance exercise. J Strength Cond Res 25(12): 3448-3455, 2011-Creatine (Cr), or methyl guanidine-acetic acid, can be either ingested from exogenous sources, such as fish or meat, or produced endogenously by the body, primarily in the liver. It is used as an ergogenic aid to improve muscle mass, strength, and endurance. Heretofore, Cr's positive therapeutic benefits in various oxidative stress-associated diseases have been reported in the literature and, recently, Cr has also been shown to exert direct antioxidant effects. Therefore, the purpose of this study was to investigate the effects of an acute bout of resistance exercise (RE) on oxidative stress response and oxidative DNA damage in male athletes and whether supplementation with Cr could negate any observed differences. Twenty-seven resistance-trained men were randomly divided into a Cr supplementation group (the Cr group [21.6 ± 3.6 years], taking 4 × 5 g Cr monohydrate per day) or a placebo (PL) supplementation group (the PL group [21.2 ± 3.2 years], taking 4 × 5 g maltodextrin per day). A double-blind research design was employed for a 7-day supplementation period. Before and after the seventh day of supplementation, the subjects performed an RE protocol (7 sets of 4 exercises using 60-90 1 repetition maximum) in the flat pyramid loading pattern. Blood and urine samples taken before, immediately, and 24-hour postexercise were analyzed for plasma malondialdehyde (MDA) and urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) excretion. Before the supplementation period, a significant increase in the urinary 8-OHdG excretion and plasma MDA levels was observed after RE. The Cr supplementation induces a significant increase in athletics performance, and it attenuated the changes observed in the urinary 8-OHdG excretion and plasma MDA. These results indicate that Cr supplementation reduced oxidative DNA damage and lipid peroxidation induced by a single bout of RE.
Cilj ove studije je upoređivanje tri različita trenana protokola (pliometrijski trening, trening... more Cilj ove studije je upoređivanje tri različita trenana protokola (pliometrijski trening, trening sa opterećenjem i njihova kombinacija) na vertikalan skok, anaerobnu moć i miićnu snagu. 48 studenata su podeljeni na četiri grupe: pliometrijski trening (n = 13), trening sa ...
The purpose of this research was to compare effect 3 different rest intervals on the squat volume... more The purpose of this research was to compare effect 3 different rest intervals on the squat volume completed during a workout. Twenty college-aged men volunteered to participate in this study (age 20.73 ± 2.60 years; body mass 80.73 ± 10.80 kg). All subjects performed 3 testing sessions, during which 4 sets of the squat was performed with 85% of a 1RM load. During each testing session, the squat was performed with a 1, 2, or 5-minute rest interval between sets. Volume was defined as the total number of repetitions completed over 4 sets for each rest condition. Statistical analysis was conducted separately for the squat. One-way repeated analyses of variance with Bonferroni post hocs demonstrated significant differences between each rest condition for both exercises tested (p < 0.05). The 5-minute rest condition resulted in the highest volume completed, followed in descending order by the 2- and 1-minute rest conditions. The ability to perform a higher volume of training with a given load may stimulate greater strength adaptations. Key PointsThere is no significant difference in the squat volume between the 1- and 2-minute rest conditions.A 5-minute rest interval between sets allow for the highest volume to be completed when training with 85% of a 1RM load.
The effect of 3 different rest periods on the acute hormonal responses to resistance exercise (RE... more The effect of 3 different rest periods on the acute hormonal responses to resistance exercise (RE) was examined in 10 experienced resistance trained men (age: 20.37 +/- 2.24 years, weight: 65.5 +/- 26.70 kg). On 3 separate sessions of an RE protocol, subjects were assigned in a random order a rest interval of 60 seconds (P60), 90 seconds (P90), or 120 seconds (P120) between sets. The RE session consisted of 4 sets of squat and bench press to failure using 85% of 1 repetition maximum. Blood draws occurred at pre-exercise (T0), immediately post (T1), and 30 minutes post (T30) exercise for measurement of serum growth hormone (GH), testosterone (TS), and blood-lactate concentrations. Serum GH concentrations were significantly higher at T1 in P60 (64%) compared with P120. Also, serum TS concentrations were significantly higher at T1 in P120 (65%) and P90 (76%) compared to P60 (p < or = 0.05). Blood-lactate concentrations significantly increased at T1 for 3 protocols, but no significant protocols differences were observed. Although, training volume by using P90 and P120 was greater than that of P60, statistically a significant difference in training volume was not observed. The results of the present study support rest period in RE sets as an important variable to increase the anabolic hormone concentrations, and it should be mentioned that short rest intervals elevated greater increase in GH concentration compared with 120-second rest. However, TS response was greater in the RE protocol with a 120-second rest interval between sets.
Journal of Strength and Conditioning Research, 2011
Rahimi, R. Creatine supplementation decreases oxidative DNA damage and lipid peroxidation induced... more Rahimi, R. Creatine supplementation decreases oxidative DNA damage and lipid peroxidation induced by a single bout of resistance exercise. J Strength Cond Res 25(12): 3448-3455, 2011-Creatine (Cr), or methyl guanidine-acetic acid, can be either ingested from exogenous sources, such as fish or meat, or produced endogenously by the body, primarily in the liver. It is used as an ergogenic aid to improve muscle mass, strength, and endurance. Heretofore, Cr's positive therapeutic benefits in various oxidative stress-associated diseases have been reported in the literature and, recently, Cr has also been shown to exert direct antioxidant effects. Therefore, the purpose of this study was to investigate the effects of an acute bout of resistance exercise (RE) on oxidative stress response and oxidative DNA damage in male athletes and whether supplementation with Cr could negate any observed differences. Twenty-seven resistance-trained men were randomly divided into a Cr supplementation group (the Cr group [21.6 ± 3.6 years], taking 4 × 5 g Cr monohydrate per day) or a placebo (PL) supplementation group (the PL group [21.2 ± 3.2 years], taking 4 × 5 g maltodextrin per day). A double-blind research design was employed for a 7-day supplementation period. Before and after the seventh day of supplementation, the subjects performed an RE protocol (7 sets of 4 exercises using 60-90 1 repetition maximum) in the flat pyramid loading pattern. Blood and urine samples taken before, immediately, and 24-hour postexercise were analyzed for plasma malondialdehyde (MDA) and urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) excretion. Before the supplementation period, a significant increase in the urinary 8-OHdG excretion and plasma MDA levels was observed after RE. The Cr supplementation induces a significant increase in athletics performance, and it attenuated the changes observed in the urinary 8-OHdG excretion and plasma MDA. These results indicate that Cr supplementation reduced oxidative DNA damage and lipid peroxidation induced by a single bout of RE.
Cilj ove studije je upoređivanje tri različita trenana protokola (pliometrijski trening, trening... more Cilj ove studije je upoređivanje tri različita trenana protokola (pliometrijski trening, trening sa opterećenjem i njihova kombinacija) na vertikalan skok, anaerobnu moć i miićnu snagu. 48 studenata su podeljeni na četiri grupe: pliometrijski trening (n = 13), trening sa ...
The purpose of this research was to compare effect 3 different rest intervals on the squat volume... more The purpose of this research was to compare effect 3 different rest intervals on the squat volume completed during a workout. Twenty college-aged men volunteered to participate in this study (age 20.73 ± 2.60 years; body mass 80.73 ± 10.80 kg). All subjects performed 3 testing sessions, during which 4 sets of the squat was performed with 85% of a 1RM load. During each testing session, the squat was performed with a 1, 2, or 5-minute rest interval between sets. Volume was defined as the total number of repetitions completed over 4 sets for each rest condition. Statistical analysis was conducted separately for the squat. One-way repeated analyses of variance with Bonferroni post hocs demonstrated significant differences between each rest condition for both exercises tested (p < 0.05). The 5-minute rest condition resulted in the highest volume completed, followed in descending order by the 2- and 1-minute rest conditions. The ability to perform a higher volume of training with a given load may stimulate greater strength adaptations. Key PointsThere is no significant difference in the squat volume between the 1- and 2-minute rest conditions.A 5-minute rest interval between sets allow for the highest volume to be completed when training with 85% of a 1RM load.
The effect of 3 different rest periods on the acute hormonal responses to resistance exercise (RE... more The effect of 3 different rest periods on the acute hormonal responses to resistance exercise (RE) was examined in 10 experienced resistance trained men (age: 20.37 +/- 2.24 years, weight: 65.5 +/- 26.70 kg). On 3 separate sessions of an RE protocol, subjects were assigned in a random order a rest interval of 60 seconds (P60), 90 seconds (P90), or 120 seconds (P120) between sets. The RE session consisted of 4 sets of squat and bench press to failure using 85% of 1 repetition maximum. Blood draws occurred at pre-exercise (T0), immediately post (T1), and 30 minutes post (T30) exercise for measurement of serum growth hormone (GH), testosterone (TS), and blood-lactate concentrations. Serum GH concentrations were significantly higher at T1 in P60 (64%) compared with P120. Also, serum TS concentrations were significantly higher at T1 in P120 (65%) and P90 (76%) compared to P60 (p < or = 0.05). Blood-lactate concentrations significantly increased at T1 for 3 protocols, but no significant protocols differences were observed. Although, training volume by using P90 and P120 was greater than that of P60, statistically a significant difference in training volume was not observed. The results of the present study support rest period in RE sets as an important variable to increase the anabolic hormone concentrations, and it should be mentioned that short rest intervals elevated greater increase in GH concentration compared with 120-second rest. However, TS response was greater in the RE protocol with a 120-second rest interval between sets.
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