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. 2009 Apr 2;6:9.
doi: 10.1186/1550-2783-6-9.

Glycine propionyl-L-carnitine Produces Enhanced Anaerobic Work Capacity With Reduced Lactate Accumulation in Resistance Trained Males

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Free PMC article

Glycine propionyl-L-carnitine Produces Enhanced Anaerobic Work Capacity With Reduced Lactate Accumulation in Resistance Trained Males

Patrick L Jacobs et al. J Int Soc Sports Nutr. .
Free PMC article

Abstract

Background: Recent research has indicated that short term administration of glycine propionyl-L-carnitine (GPLC) significantly elevates levels of nitric oxide metabolites at rest and in response to reactive hyperaemia. However, no scientific evidence exists that suggests such supplementation enhances exercise performance in healthy, trained individuals. The purpose of this study was to examine the effects of GPLC on the performance of repeated high intensity stationary cycle sprints with limited recovery periods in resistance trained male subjects.

Methods: In a double-blind, placebo-controlled, cross-over design, twenty-four male resistance trained subjects (25.2 +/- 3.6 years) participated in two test sessions separated by one week. Testing was performed 90 minutes following oral ingestion of either 4.5 grams GPLC or 4.5 grams cellulose (PL), in randomized order. The exercise testing protocol consisted of five 10-second Wingate cycle sprints separated by 1-minute active recovery periods. Peak (PP) and mean values (MP) of sprint power output and percent decrement of power (DEC) were determined per bout and standardized relative to body masss. Heart rate (HR) and blood lactate (LAC) were measured prior to, during and following the five sprint bouts.

Results: Significant main effects (p < 0.001) were observed for sprint bout order in values of PP, MP, DEC, and HR. There were significant main effects detected for condition in PP and MP (p < 0.05), with values across the five sprint bouts 2.6 - 15% greater with GPLC. Significant statistical interactions were detected between bout order and condition for both PP and MP (p < 0.05). There was a significant main effect of condition for LAC, LAC values 15.7% lower 4 min post-exercise with GPLC (p = 0.09) and with GPLC resulting in 16.2% less LAC at 14 min post-exercise (p < 0.05).

Conclusion: These findings indicate that short-term oral supplementation of GPLC can enhance peak power production in resistance trained males with significantly less LAC accumulation.

Figures

Figure 1
Figure 1
Peak power (PP) determined during repeated cycling sprints with Placebo (dotted columns) and with GPLC (darkened columns). Note: Significant condition main effect (p < 0.01) and interaction effect (p < 0.05). Significant paired time contrasts for sprints 3, 4, and 5 (p < 0.05). Values are mean ± SD. * denotes statistically significant difference between conditions (p < 0.05)
Figure 2
Figure 2
Mean power (MP) determined during repeated cycling sprints with Placebo (dotted columns) and with GPLC (darkened columns). Note: Significant interaction effect (p < 0.05). Significant paired time contrasts for sprints 4 and 5 (p < 0.05). Values are mean ± SD. * denotes statistically significant difference between conditions (p < 0.05)
Figure 3
Figure 3
Decrement in power output (DEC) determined during repeated cycling sprints with Placebo (dotted columns) and with GPLC (darkened columns). Note: No significant main condition or interaction effects (p > 0.05). Significant paired time contrast for sprint 5 (p < 0.05). Values are mean ± SD
Figure 4
Figure 4
Lactate (PP) assessed during at rest and 4 min and 14 min following repeated cycling sprints with Placebo (dotted columns) and with GPLC (darkened columns). Note: Significant condition main effect (p < 0.05). Significant paired time contrast for 14 min post sprints (p < 0.05) but not 4 min post sprint (p = 0.09). * denotes statistically significant difference between conditions (p < 0.05)
Figure 5
Figure 5
Heart rate (HR) assessed at rest, during and following repeated cycling sprints with Placebo (dotted columns) and with GPLC (darkened columns). Values are mean ± SD.

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