3 RESEARCH ARTICLES
Jooyoung Kim,1 Joohyung Lee,1 Seungho Kim,2 Daeyoung Yoon,2 Jieun Kim,1 and Dong Jun Sung3,*
– Researchers have suggested creatine reduces muscle damage by decreasing inflammatory response and oxidative stress, regulating calcium homeostasis, and activating satellite cells
– Creatine may be for preventing muscle damage and facilitating recovery from high-intensity exercise
Ellen Cristini de Freitas
– 25 players under age 20 y were randomly assigned to two groups:
(1) Cr supplemented (2) placebo.
– Double-blind controlled supplementation was performed using Cr (0.3 g/kg) or placebo tablets for 7 d
– Before and after 7 d of supplementation, the athletes performed two consecutive Running-based Anaerobic Sprint Tests (RAST)
– RAST consisted of six 35-m sprint runs at maximum speed with 10 sec rest between them
– Blood samples were collected just prior to start of test (pre), just after the completion (0 h), and 1 h after completion
(1) Average, maximum, and minimum power values were greater in the Cr-supplemented group compared with placebo
(2) There were significant increases in plasma tumor necrosis factor alpha (TNF-α) and C-reactive protein (CRP) up to 1 h after acute sprint exercise in placebo group
(2) Malondialdehyde, lactate dehydrogenase (LDH), catalase, and superoxide dismutase enzymes also were increased after exercise in both groups.
(3) Red blood cell glutathione was lower after exercise in both groups.
(4) Cr supplementation reversed the increase in TNF-α and CRP as well as LDH induced by acute exercise.
(5) Controversially, Cr supplementation did not inhibit the rise in oxidative stress markers.
(6) Also, antioxidant enzyme activity was not different between placebo and Cr-supplemented groups.
– Cr inhibited the increase of inflammation markers TNF-α and CRP, but not oxidative stress markers, due to acute exercise
– 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
– 27 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)
(B) placebo (PL) supplementation group (the PL group [21.2 ± 3.2 years], taking 4 × 5 g maltodextrin per day).
– 7-day supplementation period.
– Before and after the 7th day of supplementation, 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
(1) Before the supplementation period, a significant increase in the urinary 8-OHdG excretion and plasma MDA levels was observed after RE
(2) Cr induces a significant increase in athletics performance, and it attenuated the changes observed in the urinary 8-OHdG excretion and plasma MDA
– Cr supplementation reduced oxidative DNA damage and lipid peroxidation induced by a single bout of RE