Exploring the effects of L-carnitine supplementation on CrossFit® performance
| ISRCTN | ISRCTN14089170 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN14089170 |
| Secondary identifying numbers | CARCT1 |
- Submission date
- 07/10/2024
- Registration date
- 29/01/2025
- Last edited
- 28/02/2025
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Other
Plain English Summary
Background and study aims
This study aims to investigate whether L-carnitine supplementation can improve performance in recreational CrossFit® athletes during a high-intensity workout called "Cindy." Specifically, whether taking L-carnitine will increase the number of repetitions completed during the workout and its effects on perceived exertion, blood pressure, and any potential side effects like gastrointestinal discomfort.
Who can participate?
The study includes adult male volunteers between the ages of 18 and 35 years old who had at least six months of CrossFit® experience and had previously completed the "Cindy" workout
What did the study involve?
Participants will be randomly assigned to take either a 3 g dose of L-carnitine or a placebo 90 minutes before performing the "Cindy" workout. Each participant takes part in two separate sessions: one with L-carnitine and one with a placebo. During the workout, the total number of repetitions, ratings of perceived exertion (RPE), blood pressure and any side effects, such as gastrointestinal issues, are recorded.
What were the possible benefits and risks of participating?
While participants will not experience direct benefits from the study, the findings provide valuable information about the effects of L-carnitine on high-intensity exercise performance. There are minimal risks involved, such as reporting minor gastrointestinal discomfort and difficulty sleeping after taking L-carnitine, but no serious adverse effects are expected to be observed.
Where was the study run from?
The study was conducted at a CrossFit® club within the Faculty of Higher Studies of Zaragoza.
When did the study start and how long did it run for?
January 2023 to December 2023
Who funded the study?
Universidad Nacional Autónoma de México
Who was the main contact?
Dr Azucena Ojeda Sanchez, a.ojeda@zaragoza.unam.mx, azucenaojedasan@yahoo.com.mx
Contact information
Scientific
Gallen Am Vadianplatz, Vadianstrasse 26
St. Gallen
9001
Switzerland
 ORCID ID |
0000-0002-2412-9103 |
|---|---|
| Phone | +41 71 534 01 31 |
| beat.knechtle@hispeed.ch |
Public
Collins Ave Ext, Artane - Whitehall
Dublin 9
D09 W6Y4
Ireland
| ORCID ID |
0000-0002-4267-9950 |
|---|---|
| Phone | +353 (1) 700 5000 |
| aslidevrimlanpir@gmail.com |
Principal Investigator
Epidemiología y Salud Pública, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México
Mexica City
04510
Mexico
| Phone | +52 36011000 Ext 69326 |
|---|---|
| a.ojeda@zaragoza.unam.mx |
Study information
| Study design | Randomized double-blind placebo-controlled crossover study |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised controlled trial |
| Study setting(s) | Fitness/sport facility, Laboratory, University/medical school/dental school |
| Study type | Efficacy |
| Participant information sheet | 46188_PIS.pdf |
| Scientific title | The effects of acute L-carnitine supplementation on CrossFit® performance: a randomized, double-blind, placebo-controlled crossover study |
| Study hypothesis | Primary Hypothesis: Acute L-carnitine supplementation will enhance exercise performance, as measured by the total number of repetitions completed by recreational CrossFit® athletes, compared to a placebo. Secondary Hypothesis: L-carnitine supplementation will result in lower ratings of perceived exertion (RPE) and more favorable blood pressure (BP) measurements during exercise compared to a placebo. |
| Ethics approval(s) |
Approved 27/11/2023, The Research Ethics Committee of National Autonomous University of Mexico (Av. Universidad 3004, Copilco Universidad, Coyoacán, Mexico City, 04510, Mexico; +52 55 5622 0000; etica.enlace@zaragoza.unam.mx), ref: FESZ/CEI/31/23 |
| Condition | The acute effects of L-carnitine supplementation on exercise performance in recreational CrossFit® practitioners |
| Intervention | In this randomized, double-blind, placebo-controlled crossover study, a free online randomisation tool (randomiser.org) was used to assign CrossFit practitioners to groups. They participated in two workout sessions in a crossover design, with no additional follow-up activities afterwards. Participants were assigned to receive either a 3 mg dose of L-carnitine tartrate or a placebo. The L-carnitine tartrate dose was administered 90 minutes before the “Cindy” workout, a CrossFit® exercise regimen. Participants completed both the L-carnitine and placebo conditions in separate sessions, with the order of administration randomized to minimize bias. The total number of repetitions completed during the workout was recorded to assess exercise performance. In addition, ratings of perceived exertion (RPE) and blood pressure (BP) measurements were collected during each session. The percent change in performance between sessions was calculated to evaluate any potential learning effect on the ergogenic benefits of L-carnitine supplementation. |
| Intervention type | Supplement |
| Primary outcome measure | Exercise performance was measured using the total number of repetitions completed during the "Cindy" workout, a high-intensity CrossFit® protocol immediately after the workout in each session |
| Secondary outcome measures | 1. Ratings of Perceived Exertion (RPE) were measured using a standard Borg scale at the end of the workout 2. Blood Pressure (BP) was measured using a standard sphygmomanometer before and after the workout session 3. Gastrointestinal issues were measured using participant self-reporting at the end of the workout |
| Overall study start date | 01/01/2023 |
| Overall study end date | 31/12/2023 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 35 Years |
| Sex | Male |
| Target number of participants | 20 |
| Total final enrolment | 20 |
| Participant inclusion criteria | 1. Trained adult males aged 18-35 years old 2. A minimum of six months of CrossFit® experience 3. Required to have previously completed the “Cindy” workout routine |
| Participant exclusion criteria | 1. Diagnosed illnesses 2. Smoking 3. Recent use of medications or supplements (within the last three months) 4. Family history of seizures 5. Musculoskeletal injuries |
| Recruitment start date | 27/11/2023 |
| Recruitment end date | 27/12/2023 |
Locations
Countries of recruitment
- Mexico
Study participating centre
Col. Ejército de Oriente
Mexico City
09230
Mexico
Sponsor information
University/education
Faculty of Higher Studies of Zaragoza
Avenida Guelato 66
Col. Ejército de Oriente
Mexico City
09230
Mexico
| Phone | +52 55 5623 0635 |
|---|---|
| azucenaojedasan@yahoo.com.mx | |
| Website | https://www.zaragoza.unam.mx/ |
"ROR" |
https://ror.org/01tmp8f25 |
Funders
Funder type
University/education
Government organisation / Local government
- Alternative name(s)
- National Autonomous University of Mexico, UNAM
- Location
- Mexico
Results and Publications
| Intention to publish date | 27/12/2024 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Available on request |
| Publication and dissemination plan | We plan to submit the results of this study for publication in Frontiers in Sports and Active Living, a peer-reviewed journal. |
| IPD sharing plan | The datasets generated during and/or analyzed during the current study will be available upon request from Beat Knechtle, beat.knechtle@hispeed.ch. The data includes individual participant data (IPD) related to performance outcomes, ratings of perceived exertion (RPE), blood pressure measurements, and any reported side effects. The data will be anonymized to protect participant confidentiality and will be shared with researchers upon request for the purpose of replicating or extending the findings of the study. Access will be granted to individuals or institutions involved in academic or scientific research, subject to approval by the study’s ethics committee. Consent for data sharing was obtained from participants as part of the informed consent process. |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | 21/10/2024 | No | Yes |
Additional files
Editorial Notes
28/02/2025: Contact details updated.
08/10/2024: Study's existence confirmed by The Research Ethics Committee of National Autonomous University of Mexico.
