Effect of Creatine Loading on Oxygen Uptake during a 1-km Cycling Time Trial. Issue 12 (December 2015)

• Record Type: Journal Article
• Authors: DE ANDRADE NEMEZIO, KLEINER MARCIO; BERTUZZI, ROMULO; CORREIA-OLIVEIRA, CARLOS RAFAELL; GUALANO, BRUNO; BISHOP, DAVID JOHN; LIMA-SILVA, ADRIANO EDUARDO
• Is Part Of: Medicine and science in sports and exercise. Volume 47:Issue 12(2015)
• Publication Date: 2015-12
• Subjects: V˙O2 SLOW COMPONENT -- ACCUMULATED OXYGEN DEFICIT -- PACING -- ALL-OUT -- SUPPLEMENTATION -- CYCLIST; Sports medicine -- Periodicals; Exercise -- Physiological aspects -- Periodicals; Exercise -- Health aspects -- Periodicals; 612.044
• DOI: 10.1249/MSS.0000000000000718
• Languages: English
• ISSNs: 0195-9131

Abstract

ABSTRACT: Purpose: For the first time, we investigated the effects of altering cellular metabolic capacitance, via a 5-d creatine (Cr) loading protocol (20 g·d −1 ), on oxygen uptake (V˙O2 ), accumulated oxygen deficit, muscle recruitment, and performance during a 1-km cycling time trial. Methods: In a double-blind, randomized, placebo-controlled design, 19 amateur cyclists were allocated to a Cr ( n = 10, V˙O2peak = 56.0 ± 7.8 mL·kg −1 ·min −1 ) or placebo ( n = 9, V˙O2peak = 56.0 ± 8.4 mL·kg −1 ·min −1 ) group, and performed a 1-km cycling time trial before and after the supplementation period. Results: Body mass was significantly increased in the Cr group ( P < 0.05), but not in the placebo group. Participants adopted an "all-out" pacing strategy in both groups. However, Cr loading reduced V˙O2 immediately after the beginning (12th to 23th seconds), and this was accompanied by a reduced aerobic and increased anaerobic contribution. The V˙O2 mean response time was slower (pre: 17.2 ± 5.6 s vs post: 19.9 ± 4.6 s), the total O2 uptake was reduced (pre: 4.64 ± 0.59 L vs post: 4.47 ± 0.53 L), and the oxygen deficit was increased (pre: 0.82 ± 0.27 L vs post: 0.98 ± 0.25 L) after Cr loading. No differences were observed in the placebo group for these variables. Plasma lactate and integrated electromyography were not altered in either group, nor was the time to complete the trial (Cr group: pre: 89.1 ± 6.7 s vs post 89.1 ± 6.2 s and placebo group: pre 85.9 ± 4.9 s vs post 87.0 ± 5.4 s). Conclusion: Cr loading slows the V˙O2 response and increases the anaerobic contribution during a 1-km cycling time trial.