Med Sci Sports Exerc 2002 Jul;34(7):1176-83 Related Articles, Links
Effects of creatine on isometric bench-press performance in resistance-trained humans.
Kilduff LP, Vidakovic P, Cooney G, Twycross-Lewis R, Amuna P, Parker M, Paul L, Pitsiladis YP.
Centre for Exercise Science and Medicine, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK.
PURPOSE: The purpose of this study was to investigate the effects of creatine (Cr) supplementation on force generation during an isometric bench-press in resistance-trained men. METHODS: 32 resistance-trained men were matched for peak isometric force and assigned in double-blind fashion to either a Cr or placebo group. Subjects performed an isometric bench-press test involving five maximal isometric contractions before and after 5 d of Cr (20 g.d-1 Cr + 180 g.d-1 dextrose) or placebo (200 g.d-1 dextrose). Body composition was measured before and after supplementation. Subjects completed 24-h urine collections throughout the study period; these were subsequently analyzed to provide total Cr and creatinine excretion. RESULTS: The amount of Cr retained over the supplementation period was 45 +/- 18 g (mean +/- SD), with an estimated intramuscular Cr storage of 43 (13-61) mmol x kg(-1) x dry weight muscle (median [range]). Four subjects in the Cr group were classified as "nonresponders" (< or =21 mmol x kg(-1) x dry weight muscle increase following Cr supplementation) and the remaining 17 subjects were classed as "responders" (> or =32 mmol x kg(-1) x dry weight muscle). For the Cr group, peak force and total force pre- or post-supplementation were not different from placebo. However, when the analysis was confined to the responders, both the change in peak force [Repetition 2: 59(81) N vs -26(85) N; Repetition 3: 45(59) N vs -26(64) N) and the change in total force (Repetition 1: 1471(1274) N vs 209(1517) N; Repetition 2: 1575(1254) N vs 196(1413) N; Repetition 3: 1278(1245) N vs -3(1118) N; Repetition 4: 918(935) N vs -83(1095) N] post-supplementation were significantly greater compared with the placebo group (P < 0.01). For the Cr group, estimated Cr uptake was inversely correlated with training status (r = -0.68, N = 21, P = 0.001). Cr significantly increased body weight (84.1 +/- 8.6 kg pre- vs 85.3 +/- 8.3 kg post-supplementation) and fat-free mass (71.8 +/- 6.0 kg pre- vs 72.6 +/- 6.0 kg post-supplementation), with the magnitude of increase being significantly greater in the responder group than in the placebo group. CONCLUSION: Five days of Cr supplementation increased body weight and fat-free body mass in resistance-trained men who were classified as responders. Peak force and total force during a repeated maximal isometric bench-press test were also significantly greater in the responders compared to the placebo group.
J Fam Pract 2002 Nov;51(11):945-51 Related Articles, Links
Does oral creatine supplementation improve strengths? A meta-analysis.
Dempsey RL, Mazzone MF, Meurer LN.
Dept of Family Community Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226.
rdempsey@mcw.edu
OBJECTIVES: Oral creatine is the most widely used nutritional supplement among athletes. Our purpose was to investigate whether creatine supplementation increases maximal strength and power in healthy adults. STUDY DESIGN: Meta-analysis of existing literature. DATA SOURCES: We searched MEDLINE (1966-2000) and the Cochrane Controlled Trials Register (through June 2001) to locate relevant articles. We reviewed conference proceedings and bibliographies of identified studies. An expert in the field was contacted for sources of unpublished data. Randomized or matched placebo controlled trials comparing creatine supplementation with placebo in healthy adults were considered. OUTCOMES MEASURED: Presupplementation and postsupplementation change in maximal weight lifted, cycle ergometry sprint peak power, and isokinetic dynamometer peak torque were measured. RESULTS: Sixteen studies were identified for inclusion. The summary difference in maximum weight lifted was 6.85 kg (95% confidence interval [CI], 5.24-8.47) greater after creatine than placebo for bench press and 9.76 kg (95% CI, 3.37-16.15) greater for squats; there was no difference for arm curls. In 7 of 10 studies evaluating maximal weight lifted, subjects were young men (younger than 36 years) engaged in resistance training. There was no difference in cycle ergometer or isokinetic dynamometer performance. CONCLUSIONS: Oral creatine supplementation combined with resistance training increases maximal weight lifted in young men. There is no evidence for improved performance in older individuals or women or for other types of strength and power exercises. Also, the safety of creatine remains unproven. Therefore, until these issues are addressed, its use cannot be universally recommended.
Med Sci Sports Exerc 2001 Dec;33(12):2111-7 Related Articles, Links
Creatine supplementation combined with resistance training in older men.
Chrusch MJ, Chilibeck PD, Chad KE, Davison KS, Burke DG.
College of Kinesiology, University of Saskatchewan, 105 Gymnasium Place, Saskatoon, Saskatchewan, S7N 5C2, Canada.
PURPOSE: To study the effect of creatine (Cr) supplementation combined with resistance training on muscular performance and body composition in older men. METHODS: Thirty men were randomized to receive creatine supplementation (CRE, N = 16, age = 70.4 +/- 1.6 yr) or placebo (PLA, N = 14, age = 71.1 +/- 1.8 yr), using a double blind procedure. Cr supplementation consisted of 0.3-g Cr.kg(-1) body weight for the first 5 d (loading phase) and 0.07-g Cr.kg(-1) body weight thereafter. Both groups participated in resistance training (36 sessions, 3 times per week, 3 sets of 10 repetitions, 12 exercises). Muscular strength was assessed by 1-repetition maximum (1-RM) for leg press (LP), knee extension (KE), and bench press (BP). Muscular endurance was assessed by the maximum number of repetitions over 3 sets (separated by 1-min rest intervals) at an intensity corresponding to 70% baseline 1-RM for BP and 80% baseline 1-RM for the KE and LP. Average power (AP) was assessed using a Biodex isokinetic knee extension/flexion exercise (3 sets of 10 repetitions at 60 degrees.s(-1) separated by 1-min rest). Lean tissue (LTM) and fat mass were assessed using dual energy x-ray absorptiometry. RESULTS: Compared with PLA, the CRE group had significantly greater increases in LTM (CRE, +3.3 kg; PLA, +1.3 kg), LP 1-RM (CRE, +50.1 kg; PLA +31.3 kg), KE 1-RM (CRE, +14.9 kg; PLA, +10.7 kg), LP endurance (CRE, +47 reps; PLA, +32 reps), KE endurance (CRE, +21 reps; PLA +14 reps), and AP (CRE, +26.7 W; PLA, +18 W). Changes in fat mass, fat percentage, BP 1-RM, and BP endurance were similar between groups. CONCLUSION: Creatine supplementation, when combined with resistance training, increases lean tissue mass and improves leg strength, endurance, and average power in men of mean age 70 yr.
J Gerontol A Biol Sci Med Sci 2003 Jan;58(1):B11-9 Related Articles, Links
Creatine supplementation enhances isometric strength and body composition improvements following strength exercise training in older adults.
Brose A, Parise G, Tarnopolsky MA.
Departments of Kinesiology and. Medicine, McMaster University, Ontario, Canada.
We sought to determine whether creatine monohydrate (CrM) supplementation would enhance the increases in strength and fat-free mass that develop during resistance exercise training in older adults. Twenty-eight healthy men and women over the age of 65 years participated in a whole-body resistance exercise program 3 days per week for 14 weeks. The study participants were randomly allocated, in a double-blind fashion, to receive either CrM (5 g/d + 2 g of dextrose; n = 14) or placebo (7 g of dextrose; n = 14). The primary outcome measurements included the following: total body mass, fat-free mass, one-repetition maximum strength for each body part, isometric knee extension, handgrip, and dorsiflexion strength, chair stand performance, 30-m walk test, 14-stair climb performance, muscle fiber type and area, and intramuscular total creatine. Fourteen weeks of resistance exercise training resulted in significant increases in all measurements of strength and functional tasks and muscle fiber area for both groups (p <.05). CrM supplementation resulted in significantly greater increases in fat-free mass and total body mass, as compared with placebo (p <.05). The CrM group also showed a greater increase in isometric knee extension strength in men and women, as compared with placebo (p <.05), and also greater gains in isometric dorsiflexion strength (p <.05), but in men only. There was a significant increase in intramuscular total creatine in the CrM group (p <.05). Finally, there were no significant side effects of treatment or exercise training. This study confirms that supervised heavy resistance exercise training can safely increase muscle strength and functional capacity in older adults. The addition of CrM supplementation to the exercise stimulus enhanced the increase in total and fat-free mass, and gains in several indices of isometric muscle strength.
MEDICINE AND SCIENCE IN SPORTS AND EXERCISE 2001;33:1674-1681
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ABSTRACT WILLOUGHBY, D. S., and J. ROSENE. Effects of oral creatine and resistance training on myosin heavy chain expression. Med. Sci. Sports Exerc., Vol. 33, No. 10, 2001, pp. 1674–1681.
Purpose: This study examined 12 wk of creatine (Cr) supplementation and heavy resistance training on muscle strength and myosin heavy chain (MHC) isoform mRNA and protein expression. Methods: Twenty-two untrained male subjects were randomly assigned to either a control (CON), placebo (PLC), or Cr (CRT) group in a double-blind fashion. Muscle biopsies were obtained before and after 12 wk of heavy resistance training. PLC and CRT trained thrice weekly using three sets of 6-8 repetitions at 85–90% 1-RM on the leg press, knee extension, and knee curl exercises. CRT ingested 6 g·d–1 of Cr for 12 wk, whereas PLC consumed the equal concentration of placebo. Results: There were no significant differences for percent body fat (P > 0.05). However, for total body mass, fat-free mass, thigh volume, muscle strength, and myofibrillar protein, CRT and PLC exhibited significant increases after training when compared to CON (P < 0.05), whereas CRT was also significantly greater than PLC (P < 0.05). For Type I, IIa, and IIx MHC mRNA expression, CRT was significantly greater than CON and PLC, whereas PLC was greater than CON (P < 0.05). For MHC protein expression, CRT was significantly greater than CON and PLC for Type I and IIx (P < 0.05) but was equal to PLC for IIa. Conclusion: Long-term Cr supplementation increases muscle strength and size, possibly as a result of increased MHC synthesis.
Performance and muscle fiber adaptations to creatine supplementation and heavy resistance training.
Volek JS, Duncan ND, Mazzetti SA, Staron RS, Putukian M, Gomez AL, Pearson DR, Fink WJ, Kraemer WJ.
Department of Kinesiology/Center for Sports Medicine, The Pennsylvania State University, University Park 16802, USA.
PURPOSE: The purpose of this study was to examine the effect of creatine supplementation in conjunction with resistance training on physiological adaptations including muscle fiber hypertrophy and muscle creatine accumulation. METHODS: Nineteen healthy resistance-trained men were matched and then randomly assigned in a double-blind fashion to either a creatine (N = 10) or placebo (N = 9) group. Periodized heavy resistance training was performed for 12 wk. Creatine or placebo capsules were consumed (25 g x d(-1)) for 1 wk followed by a maintenance dose (5 g x d(-1)) for the remainder of the training. RESULTS: After 12 wk, significant (P < or = 0.05) increases in body mass and fat-free mass were greater in creatine (6.3% and 6.3%, respectively) than placebo (3.6% and 3.1%, respectively) subjects. After 12 wk, increases in bench press and squat were greater in creatine (24% and 32%, respectively) than placebo (16% and 24%, respectively) subjects. Compared with placebo subjects, creatine subjects demonstrated significantly greater increases in Type I (35% vs 11%), IIA (36% vs 15%), and IIAB (35% vs 6%) muscle fiber cross-sectional areas. Muscle total creatine concentrations were unchanged in placebo subjects. Muscle creatine was significantly elevated after 1 wk in creatine subjects (22%), and values remained significantly greater than placebo subjects after 12 wk. Average volume lifted in the bench press during training was significantly greater in creatine subjects during weeks 5-8. No negative side effects to the supplementation were reported. CONCLUSION: Creatine supplementation enhanced fat-free mass, physical performance, and muscle morphology in response to heavy resistance training, presumably mediated via higher quality training sessions.
Effects of training and creatine supplement on muscle strength and body mass.
Francaux M, Poortmans JR.
Institut Superieur d'Education Physique et de Kinesitherapie, Universite Libre de Bruxelles, Brussels, Belgium.
francaux@edph.ucl.ac.be
The purpose of this study was to test the effect of creatine supplement on the size of the extra- and intracellular compartments and on the increase of isokinetic force during a strength training-program. Twenty-five healthy male subjects (age 22.0+/-2.9 years) participated in this experiment. Seven subjects formed the control-group. They did not complete any training and did not have any dietary supplement. The eighteen other subjects were randomly divided into a creatine- (n = 8) and a placebo-group (n = 10). They were submitted to a controlled strength-training program for 42 days followed by a detraining period of 21 days. Creatine and placebo were given over a period of 9 weeks. The size of the body water compartments was assessed by bioimpedance spectroscopy and the isokinetic force was determined during a single squat by means of an isokinetic dynamometer. These measurements were completed beforehand, at the end of the training period, and after the determining period. Both placebo- and creatine-group increased the isokinetic force by about 6% after the training period, showing that creatine ingestion does not induce a higher increase of the force measured during a single movement. No change in body mass was observed in the control- and placebo-groups during the entire experiment period while the body mass of the creatine-group was increased by 2 kg (P < 0.001). This change can be attributed partially to an increase (P = 0.039) in the body water content (+1.11), and more specifically, to an increase (P < 0.001) in the volume of the inter-cellular compartment (+0.61). Nevertheless, the relative volumes of the body water compartments remained constant and therefore the gain in body mass cannot be attributed to water retention, but probably to dry matter growth accompanied with a normal water volume.
Muscle glycogen supercompensation is enhanced by prior creatine supplementation.
Nelson AG, Arnall DA, Kokkonen J, Day R, Evans J.
Department of Kinesiology, Louisiana State University, Baton Rouge, LA 70803, USA.
anelso@lsu.edu
PURPOSE: Recently, it was shown that glycogen supercompensation tended (P = 0.06) to be greater if creatine and glycogen were loaded simultaneously. Because the authors suggested that creatine loading increased cell volumes and, therefore, enhanced glycogen supercompensation, we decided to determine whether an enhanced glycogen supercompensation could be realized if the glycogen loading protocol was preceded by a 5-d creatine load. METHODS: Twelve men (19-28 yr) performed two standard glycogen loading protocols interspersed with a standard creatine load of 20 g.d(-1) for 5 d. The vastus lateralis muscle was biopsied before and after each loading protocol. RESULTS: The initial glycogen loading protocol showed a significant 4% increase (P < 0.05) in muscle glycogen (Delta upward arrow 164 +/- 87 mmol.kg(-1) d.m.), and no change (P > 0.05) in total muscle creatine. Biopsies pre- and post-creatine loading showed significant increases in total muscle creatine levels in both the left leg (Delta upward arrow 41.1 +/- 31.1 mmol.kg(-1) d.m.) and the right leg (Delta upward arrow 36.6 +/- 19.8 mmol.kg(-1) d.m.), with no change in either leg's muscle glycogen content. After the final glycogen loading, a significant 53% increase in muscle glycogen (Delta upward arrow 241 +/- 150 mmol.kg-1 d.m.) was detected. Finally, the postcreatine load total glycogen content (694 +/- 156 mmol.kg(-1) d.m.) was significantly (P < 0.05) greater than the precreatine load total glycogen content (597 +/- 142 mmol.kg(-1) d.m.). CONCLUSION: It is suggested that a muscle's glycogen loading capacity is influenced by its initial levels of creatine and the accompanying alterations in cell volume.
