Effect of Oral Supplementation with L-Carnitine on Performance Time in a 5000 m Race and Responses of Free Fatty Acid and Carnitine Concentrations in Trained-Endurance Athletes

Mohammad Fayiz Abumoh'D,Michael Yong Hwa Chia,Walid Alsababha

doi:10.26773/mjssm.210901

Abstract

This study was designed to determine the effect of oral supplementation with L-carnitine on the performance time in a 5000 m race. In addition, free fatty acid, blood carnitine, lactate, and glucose responses to the race following the supplementation period were measured. Twenty male trained-endurance athletes were randomly divided into two groups (L-carnitine, n = 10 (22.13 ± 2.66 yrs) or placebo, n = 10 (21.63 ± 2.23 yrs)). The study was performed with a randomized, double-blind, placebo-controlled parallel-group, in which participants ingested an L-carnitine supplement or a placebo 2 × 1.5 g/day for 3 weeks. Athletes completed a 5000 m race before and after the supplementation period. Blood samples were collected from each athlete before and after the race, preand post-supplementation to measure the physiological responses. Data showed that there were no differences in performance time before (p=0.624) and after (p=0.407) supplementation period between groups and within a group (p>0.05). No differences existed in physiological responses between groups after supplementation before beginning the race (p>0.05), except for the blood carnitine level, which was significantly higher in the L-carnitine than the placebo (P=0.001) group. After the finish of the race, however, data showed better physiological responses in response to L-carnitine supplementation compared to the placebo group (p<0.05). In conclusion, although L-carnitine supplementation increases blood carnitine concentration, it has no beneficial effect on performance time of 5000 m race probably due to the short duration of the race; it might also have no ergogenic effect.

Highlights

Despite the obvious cardiopulmonary benefits associated with distance running in a physically active population, several potential liming factors have been observed in endurance athletes (Abbias & Laursen, 2005)
This study hypothesized that L-carnitine may enhance performance by using more fatty acids that produce more than 100 adenosine triphosphate (ATP) in each molecule and reducing glycogen utilization
There were no differences in the physiological parameters between the pre- and post-supplementation periods within a group (p>0.05), except for blood carnitine, which was significantly higher after than before L-carnitine supplementation (Table 2)

Summary

Introduction

Despite the obvious cardiopulmonary benefits associated with distance running in a physically active population, several potential liming factors have been observed in endurance athletes (Abbias & Laursen, 2005). Oral supplementation with L-carnitine is used by endurance athletes to increase its content in skeletal muscle, increase fatty acid oxidation during exercise (Brass, & Hiatt, 1998), decrease toxic acyl groups (Peters et al, 2015; Stumpf et al, 1985), maintain the activity of pyruvate dehydrogenase (Brass, & Hiatt, 1998), preserve muscle glycogen, and delay muscular fatigue (Brass, & Hiatt, 1998; Smith, Fry, Tschume, & Bloomer, 2008; Wall et al, 2013). The increased use of fatty acids for energy production during prolonged exercise is beneficial to runners because it reduces muscle glycogen and increases aerobic capacity. This study hypothesized that L-carnitine may enhance performance by using more fatty acids that produce more than 100 adenosine triphosphate (ATP) in each molecule and reducing glycogen utilization

Participants

Study design

Results

Discussion

Conclusion