Muscle InjuriesMIRTPDNCT07012408
Muscle Injury RTP Design in Football; Effects of Backward Design vs Forward Design.
A study testing Return to play program with progressive design and Return to play program with regressive design in people with Muscle Injuries and Football Players, run by Universitat de les Illes Balears at 1 site in Spain.
Trial summary
Introduction "Return-to-play" (RTP) is an English term that corresponds to "return to competition". It is important to understand that this return is a constant, dynamic, and personalized decision-making process . Read more about this study
- Who is it for?
- Ages 18 to 40 years, men only
- Conditions the study is for
- Muscle Injuries, Football Players
- What is being tested?
- Return to play program with progressive design and Return to play program with regressive design
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 74 participants
- Where
- 1 siteSpain
- Study dates
- 1 Sep 2025to 1 Sep 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- Men only
- No healthy volunteers
- Adult
Who may be able to join
- Male soccer players.
- Diagnosed with a muscle injury via magnetic resonance imaging (MRI) during the three year study period.
- They will all belong to the same club.
- Age will be between 18 and 40 years old.
Who cannot join
- Patients (Muscle injuries) that do not cause players to miss training or competitions.
- Patients voluntarily decide not to participate in the study or abandon the RTP process due to transfers or other exceptional causes.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Spain1 site
University of Balearic Islands
Palma de Mallorca, Balearic Islands, 07010
Olga Velasco, PhD Physio, +34 617 649 807, olga.velasco@uib.es
Carles Pedret, PhD MD, +34 609 624 203, info@carlespedret.com
About this study
Official title: Muscle Injury Return To Play Design in Football; Effects of Backward Design Versus Forward Design . A Randomized Controlled Trial
Introduction
"Return-to-play" (RTP) is an English term that corresponds to "return to competition". It is important to understand that this return is a constant, dynamic, and personalized decision-making process . The main objective of RTP is not to predict the exact moment of an athlete's return; rather, it is to prevent new injuries. For this, adequate decision-making is necessary. There are several important steps in the process, including correct diagnosis, strict control of workloads, and intelligent management of modifiers intrinsic to the sport that can lead to anxiety and stress
Read more
How are the pieces of the RTP puzzle arranged and managed?
How are RTP processes evaluated today?
How should RTP be understood? Should it be understood statically, as a checklist, or as a constant decision-making process involving the player?
Main objective: Evaluate the design of the RTP process for muscle injuries in sports.
Specific objectives:
- To compare two RTP designs and evaluate how their design influences the anxiety experienced by the player.
- Identify variables that may be altered when choosing a regressive or progressive RTP design, such as sleep quality and cortisol level.
- To establish direction in the design of the RTP process.
- Create complete clinical guidelines on muscle injuries in sports with a focus on RTP design.
Material and Methods
Definition of the Study Subjects
The subjects of the study will be all players belonging to the first or B team who suffer a muscle injury diagnosed by magnetic resonance imaging. At the time of injury, they will be randomly assigned to either the control group (following a regressive RTP design) or the intervention group (following a progressive RTP design). Masking will be double-blind. The sample size will be N=74.
The secondary variables will be recorded in the database after diagnosis by MRI. Subsequently, the primary variables will be measured and recorded at the beginning, middle, and end of the RTP period.
It is estimated that approximately half of the necessary sample size has been reached: about 37 subjects with muscle injury. The first statistical analysis will then be carried out to observe the preliminary results.
After three years, once the analysis has been completed, the results and conclusions will be written up for publication in a journal.
Read the detailed description
Capturing and Recruiting Participants
Since the players are from the same club and suffer muscle injuries, they will be included in the control and intervention groups for three years. The following section will explain that the sampling technique is consecutive and that participants can take part in the study several times, as long as they have a muscle injury diagnosed by resonance. Relapses of the same injury or injuries in the same or different muscle groups will also be included in the sample. The head of the club's medical service and collaborating researcher, Dr. José María Villalón Alonso, will recruit the participants. After the diagnostic test (MRI) is performed and the diagnosis and prognosis are established, the participants will be handed over to the recovery specialists, who will design the RTP. The specialists and the participants (players) will be blinded in the same way.
Allocation Procedure/Randomization
Subjects (muscle injuries) have the same probability (50%) of being allocated to the control or intervention group, regardless of previous allocations.
Justification of Sample Size
A type of consecutive sampling will be carried out based on the average probability that a soccer player will suffer a muscular injury. On average, each player will suffer 0.6 muscular injuries per season. In a team of 25 soccer players, this translates to an average of 15 muscular injuries per season. By contrasting this data with the club's database, we can verify the accuracy of this estimate. According to this statistical data, the population from which we will extract the sample will be the total number of muscle injuries suffered by the two teams of Club Atlético Madrid over three years:
0.6 (injuries) x 50 (players) x 3 years = 90 muscle injuries. Using the Grammo sample calculator with a relative error of 5% and a 95% confidence interval, we will calculate the necessary sample size for the sample to be representative, which will be N = 74.
Statistical Analysis Plan:
Phase 1: Use Levene's test to check if the variances of the control and intervention groups are equal.
Phase 2: Use a t-test to determine if there is a significant difference between the means of the control and intervention groups, and to establish whether the null hypothesis (H0) or the alternative hypothesis (HA) is true.
Phase 3: Perform a bivariate study of the relationship between anxiety (dependent variable) and estimated prognosis (independent variable) using Pearson's correlation coefficient.
Phase 4: Conduct a multivariate study through multiple regression between the dependent variable, sleep quality, and the independent variables, age, type of affected tissue, and cortisol level.
Phase 5: Perform a multivariate study through simple linear regression between the dependent variable, anxiety, and the independent variable, previous injuries in the same musculature.
Ethical and Legal Aspects:
Compliance with the standards of Good Clinical Practice, the Declaration of Helsinki, the Oviedo Convention, and the Personal Data Protection and Guarantee of Digital Rights Act (LO 3/2018, December 5, 2018), as well as the regulations for managing clinical histories.
The investigator undertakes to comply with the aforementioned rules throughout the development of the research protocol, as well as in the presentation to this ethics committee, for which the investigator must provide a certificate of Good Clinical Practice (GCP). The collaborating investigators also have this GCP certificate.
Informed Consent Form:
The patient information sheet and informed consent form are both attached in Annexes 1 and 2.
The confidentiality of information collected in the context of the study is guaranteed.
Data Controller: Óscar Vicente Rodríguez TLF: 699 874 059 Email: oscarvicente90@gmail.com
Purpose of data collection: Clinical and epidemiological research.
Maximum period of data retention: The data will be kept for four years (three years for the duration of the study and one extra year for future research).
Processing, communicating, and transferring the personal data of all participating subjects will comply with the provisions of Organic Law 3/2018 of December 5 on the protection of personal data and the guarantee of digital rights.
In accordance with the aforementioned legislation, you may exercise your rights of access, rectification, deletion, opposition, and limitation of data processing. You may also transfer your data to an authorized third party (portability). For these requests, please contact the principal investigator responsible for processing at oscarvicente90@gmail.com or C/Moreno Torroba 10, 1o B, CP. 28220 Majadahonda, Madrid.
The data will be computerized and incorporated into an automated personal data system that complies with all security measures for restricted access, as described in this document.
To guarantee the confidentiality of the obtained information:
Your data and the sample will be identified by a code, and only the study physician and their collaborators will be able to relate this data to you and your medical history. Therefore, your identity will not be disclosed to anyone except in case of medical emergency or legal or administrative requirement.
Only the essential data necessary for the study will be transmitted to third parties and other countries. In no case will the data contain information that can directly identify you, such as your name, initials, address, or social security number. If this transfer occurs, it will be for the aforementioned study purposes and will guarantee confidentiality with at least the level of protection guaranteed by the legislation in force in our country.
Access to your personal information will be restricted to the study physiotherapist, collaborators, health authorities, the Balearic Islands Research Ethics Committee, and authorized personnel when required to verify the study's data and procedures, always maintaining confidentiality in accordance with current legislation.
You may contact the Spanish Data Protection Agency with any claims related to the processing of your personal data.
The handling of biological samples will be in accordance with Law 14/2007 and Royal Decree 1716/2011.
Saliva samples to determine cortisol levels will be collected at the Ciudad Deportiva Atlético de Madrid clinic on three occasions: at the beginning of the RTP, after the magnetic resonance imaging diagnosis, halfway through the established prognosis, and the day before the RTP ends. The analysis will be performed at the same clinic, where, at the end of the cortisol measurement, the saliva will be discarded and only the recorded cortisol value will be kept.
Any risks associated with the procedure used to collect these samples are covered by the study insurance.
The sample will be coded and treated confidentially throughout this study. A code will be used to link the sample to you, and only the investigator and his staff will be able to decipher it to preserve your identity.
If additional data or samples are needed, your physical therapist will contact you to request your cooperation.
You will be informed of the reasons and asked again for your consent if necessary.
It will not receive any economic benefits from the donation of samples or the transfer of provided data, nor will it have any rights to possible commercial benefits from discoveries resulting from the research.
The samples will be analyzed in the Ciudad Deportiva Atlético de Madrid laboratory and stored for four years in case additional analyses related to the study's objectives are necessary. The person responsible for the samples will be the study promoter during this process.
At the end of the research period, your sample may be:
- Destroyed
- Anonymized (i.e., the link between the sample and you will be completely destroyed so that neither the researcher nor any other team member will be able to identify to whom your sample belongs again).
- Incorporated into a collection managed by researcher Óscar Vicente Rodríguez at the Ciudad Deportiva Atlético de Madrid so that it can continue to be used in the "Stress and Muscle Injury" study and line of research. ́
Samples are stored in the Ciudad Deportiva Atlético de Madrid biobank for use in other research projects, which may be unrelated to the initial study for which consent was given. The biobank may provide samples to authorized projects, including those abroad, with prior approval from the scientific and ethics committees. You may contact the biobank to obtain information on projects in which your samples were used.
Insurance Policy or Justification of Absence for Experimental Studies
Mr. Óscar Vicente Rodríguez is the principal investigator and has the following identification number: 35.572.548, and is a member with no. 1224, is registered in the Collective Policy of Professional Civil Responsibility, to which the Official College of Physiotherapists of the Balearic Islands adheres, with number 531000009 from A.M.A. (Agrupación Mutual Aseguradora - La Mutua de los Profesionales Sanitarios). Annex 3.
Commitment to publishing the results
The principal investigator is committed to publishing the results, regardless of their nature, since there is no conflict of interest. This trial will be part of the doctoral student's (principal investigator) thesis, which guarantees the publication of the results to improve the design of the RTP process.
Financial report and source of financing
The project has no private funding other than the 3,235.45 euros provided by PI Oscar Vicente Rodriguez for the cortisol ELISA measurement kits, Oura rings, and tablets used to record expenses. The MRI and radiological report expenses are free for the club due to the entity's nature, with no conflict of interest. The same applies to the team of statisticians who can analyze the results. They are part of the UIB and collaborate with doctoral theses. This essay is one such work. Regarding the CEIm of the Balearic Islands, this trial is exempt from fees (see the documentation), as it is part of the UIB's Doctoral School studies.
- Conditions
- Muscle Injuries, Football Players
- Being tested
- Return to play program with progressive design, Return to play program with regressive design
- Keywords
- Return to play, Design, effects
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Return to play program with progressive designOther
Also called IG
This design has more open objectives than the regressive design. In the progressive design, the duration of the return-to-play program is not determined by a future date, but rather by the player's daily progress. This design is less commonly used for scheduling tasks and planning work. It is intended to be compared with the regressive design to determine which is more appropriate.
Return to play program with regressive designOther
Also called CG
Control Group: Subjects with muscle injuries assigned to this group will follow a Return to Play program with a regressive design. This design has fixed times and objectives from the beginning of the program to predict the athlete's exact discharge time. This design is commonly used for scheduling tasks and planning work. It is intended to evaluate the benefits and drawbacks of the design and compare them with those of the progressive design to determine which is more appropriate.
| Study group | Role | What they receive |
|---|---|---|
| Intervention Group | Active comparator | The intervention group: Subjects with muscle injuries who are assigned to this group will follow a return-to-play program with a progressive design. Receives: Other: Return to play program with progressive design |
| Control Group | Experimental | Control Group: The subjects (muscle injuries) that are assigned to this group will follow a Return to Play program with regressive design. Receives: Other: Return to play program with regressive design |
What is being measured
The primary outcome is the main question the study is designed to answer.
Anxiety
Player Anxiety During the Return-to-Play Process. GAD-7 Anxiety scale.
This is calculated by assigning scores of 0, 1, 2, and 3 to the response categories, respectively,of "not at all," "several days," "more than half the days," and "nearly every day."
GAD-7 total score for the seven items ranges from 0 to 21.
0-4: minimal anxiety 5-9: mild anxiety 10-14: moderate anxiety 15-21: severe anxiety
Measured: It will be measured at the beginning, middle, and end of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Sleep quality
The quality of the player's sleep during the Return to Play process. This is measured with the Oura Ring, which uses a validated scale to quantify sleep quality.
Oura's Sleep Score.
85-100: Optimal sleep quality. 70-84: Good sleep quality. 60-69: Fair sleep quality. 0-59: Areas for improvement are needed.
Measured: It will be measured at the beginning, middle, and end of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Stress (cortisol)
Stress (cortisol) during the return-to-play process. We will measure it with the ELISA salivary kit to see how this hormone, which is directly related to the stress experienced by the athlete, varies.
Cortisol levels are typically measured in micrograms per deciliter (mcg/dL) and fluctuate throughout the day, with the highest levels in the morning and the lowest at night. Normal ranges vary depending on the time of day and the testing method (blood, urine, or saliva), but generally, a healthy individual will have cortisol levels between 10-20 mcg/dL in the early morning (6-8 am) and 3-10 mcg/dL around 4 pm
Measured: It will be measured at the beginning, middle, and end of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Heart Rate Variability
Player Heart Rate Variability During the Return-to-Play Process. Ouraring device.
Interpreting HRV Scores:
High HRV (e.g., 70 or higher):
Associated with good health, a balanced autonomic nervous system, and better adaptability.
Moderate HRV (e.g., 50-70):
May indicate a need for improvement in areas like sleep, stress management, or nutrition.
Low HRV (e.g., below 50):
May indicate increased risk of health problems and a need for addressing underlying issues.
Measured: It will be measured at the beginning, middle, and end of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Secondary outcomes (6)
Age
Age of player who suffered the muscle injury
Measured: It will be measured and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
History of previous muscle injuries in the same muscle.
History (Yes or No) of previous muscle injuries in the same muscle that suffers the injury that is included in the study.
Measured: It will be determined and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Type of tissue involved in the muscle injury.
The type of tissue involved in the muscle injury is indicated by the radiological report and the BAMIC scale.
Measured: It will be determined and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
The estimated medical prognosis of the player's discharge.
The estimated medical prognosis of the player's discharge is reported in the radiology report and categorized using the BAMIC scale.
The British Athletics Muscle Injury Classification proposes a new system, based on the available evidence, which should provide a sound diagnostic base for therapeutic decision-making and prognostication. Injuries are graded 0-4 based on MRI features, with Grades 1-4 including an additional suffix 'a', 'b' or 'c' if the injury is 'myofascial', 'musculo-tendinous' or 'intratendinous'.
Measured: It will be determined and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Weight
Player weight in the moment of start Return to play
Measured: It will be measured and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Height
Height of player
Measured: It will be measured and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Jun 2025
- Study start1 Sep 2025 (estimated)
- Primary completion3 Mar 2027 (estimated)
- Study completion1 Sep 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (30)Papers the sponsor has linked to this study.
- Other trials for Muscle InjuriesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This is a randomized, double-blind, single-center controlled clinical trial. There will be two groups: a control group and an intervention group. The study will be carried out in the work environment of the principal investigator and doctoral student at the University of the Balearic Islands (UIB) and Club Atlético de Madrid. The study will focus on the first and B teams, which are based at the Ciudad Deportiva del Cerro del Espino in Majadahonda, Madrid. The study will be included in the principal investigator's doctoral thesis.
- Masking
- Double blind
- Who is masked
- Participant, Care provider
- Enrolment
- 74 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universitat de les Illes Balears
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Oscar Vicente Rodriguez, Universitat de les Illes Balears
- Investigators
- Olga Velasco, Phd Physio, Study director, University of Balearic Islands
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07012408
- Sponsor's protocol ID
- UniversitatBalears
- Acronym
- MIRTPD
- Status last verified
- Jun 2025
- First submitted
- 31 May 2025
- Last updated
- 18 Jun 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: As part of a doctoral program's research plan, this essay's IPD will be shared with the thesis directors. The IPD is confidential and is only for this research.
Publications
Orchard JW, Chaker Jomaa M, Orchard JJ, Rae K, Hoffman DT, Reddin T, Driscoll T. Fifteen-week window for recurrent muscle strains in football: a prospective cohort of 3600 muscle strains over 23 years in professional Australian rules football. Br J Sports Med. 2020 Sep;54(18):1103-1107. doi: 10.1136/bjsports-2019-100755. Epub 2020 Feb 5.
PubMed 32024646Dhillon H, Dhillon S, Dhillon MS. Current Concepts in Sports Injury Rehabilitation. Indian J Orthop. 2017 Sep-Oct;51(5):529-536. doi: 10.4103/ortho.IJOrtho_226_17.
PubMed 28966376Dattilo M, Antunes HKM, Galbes NMN, Monico-Neto M, DE Sa Souza H, Dos Santos Quaresma MVL, Lee KS, Ugrinowitsch C, Tufik S, DE Mello MT. Effects of Sleep Deprivation on Acute Skeletal Muscle Recovery after Exercise. Med Sci Sports Exerc. 2020 Feb;52(2):507-514. doi: 10.1249/MSS.0000000000002137.
PubMed 31469710Tabor J, La P, Kline G, Wang M, Bonfield S, Machan M, Wynne-Edwards K, Emery C, Debert C. Saliva Cortisol as a Biomarker of Injury in Youth Sport-Related Concussion. J Neurotrauma. 2023 Feb;40(3-4):296-308. doi: 10.1089/neu.2022.0190. Epub 2022 Sep 21.
PubMed 35906800Gomez-Espejo V, Olmedilla A, Abenza-Cano L, Garcia-Mas A, Ortega E. Psychological readiness to return to sports practice and risk of recurrence: Case studies. Front Psychol. 2022 Sep 23;13:905816. doi: 10.3389/fpsyg.2022.905816. eCollection 2022.
PubMed 36211933Orchard J, Best TM, Verrall GM. Return to play following muscle strains. Clin J Sport Med. 2005 Nov;15(6):436-41. doi: 10.1097/01.jsm.0000188206.54984.65.
PubMed 16278548Hoy MK, Stache S Jr, Roedl JB. Hamstring Injuries: A Paradigm for Return to Play. Semin Musculoskelet Radiol. 2024 Apr;28(2):119-129. doi: 10.1055/s-0043-1778027. Epub 2024 Mar 14.
PubMed 38484764Wong S, Ning A, Lee C, Feeley BT. Return to sport after muscle injury. Curr Rev Musculoskelet Med. 2015 Jun;8(2):168-75. doi: 10.1007/s12178-015-9262-2.
PubMed 25742905Schulz KF, Altman DG, Moher D; CONSORT Group. CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials. BMJ. 2010 Mar 23;340:c332. doi: 10.1136/bmj.c332.
PubMed 20332509Pollock N, James SL, Lee JC, Chakraverty R. British athletics muscle injury classification: a new grading system. Br J Sports Med. 2014 Sep;48(18):1347-51. doi: 10.1136/bjsports-2013-093302. Epub 2014 Jul 16.
PubMed 25031367Hagglund M, Walden M, Ekstrand J. Previous injury as a risk factor for injury in elite football: a prospective study over two consecutive seasons. Br J Sports Med. 2006 Sep;40(9):767-72. doi: 10.1136/bjsm.2006.026609. Epub 2006 Jul 19.
PubMed 16855067Papacosta E, Nassis GP. Saliva as a tool for monitoring steroid, peptide and immune markers in sport and exercise science. J Sci Med Sport. 2011 Sep;14(5):424-34. doi: 10.1016/j.jsams.2011.03.004. Epub 2011 Apr 7.
PubMed 21474377Svensson T, Madhawa K, Nt H, Chung UI, Svensson AK. Validity and reliability of the Oura Ring Generation 3 (Gen3) with Oura sleep staging algorithm 2.0 (OSSA 2.0) when compared to multi-night ambulatory polysomnography: A validation study of 96 participants and 421,045 epochs. Sleep Med. 2024 Mar;115:251-263. doi: 10.1016/j.sleep.2024.01.020. Epub 2024 Jan 26.
PubMed 38382312Palsson TS, Rubio-Peiroten A, Domenech-Garcia V. Sleep deprivation increases pain sensitivity following acute muscle soreness. Sleep Med. 2023 Sep;109:75-81. doi: 10.1016/j.sleep.2023.06.010. Epub 2023 Jun 24.
PubMed 37423022Lowe B, Decker O, Muller S, Brahler E, Schellberg D, Herzog W, Herzberg PY. Validation and standardization of the Generalized Anxiety Disorder Screener (GAD-7) in the general population. Med Care. 2008 Mar;46(3):266-74. doi: 10.1097/MLR.0b013e318160d093.
PubMed 18388841
Study at a glance
From the registry record, last updated by the sponsor on 18 Jun 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Muscle Injury Return To Play Design in Football; Effects of Backward Design Versus Forward Design . A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07012408
- Acronym / sponsor ID
- MIRTPD / UniversitatBalears
- Conditions
- Muscle Injuries, Football Players
- Keywords
- Return to play, Design, effects
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 74 participants (estimated)
- Lead sponsor
- Universitat de les Illes BalearsUniversity, hospital or other
- Study start
- 1 Sep 2025 (estimated)
- Primary completion
- 3 Mar 2027 (estimated)
- Study completion
- 1 Sep 2028 (estimated)
- First posted
- 10 Jun 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Introduction
"Return-to-play" (RTP) is an English term that corresponds to "return to competition". It is important to understand that this return is a constant, dynamic, and personalized decision-making process . The main objective of RTP is not to predict the exact moment of an athlete's return; rather, it is to prevent new injuries. For this, adequate decision-making is necessary. There are several important steps in the process, including correct diagnosis, strict control of workloads, and intelligent management of modifiers intrinsic to the sport that can lead to anxiety and stress
How are the pieces of the RTP puzzle arranged and managed?
How are RTP processes evaluated today?
How should RTP be understood? Should it be understood statically, as a checklist, or as a constant decision-making process involving the player?
Main objective: Evaluate the design of the RTP process for muscle injuries in sports.
Specific objectives:
- To compare two RTP designs and evaluate how their design influences the anxiety experienced by the player.
- Identify variables that may be altered when choosing a regressive or progressive RTP design, such as sleep quality and cortisol level.
- To establish direction in the design of the RTP process.
- Create complete clinical guidelines on muscle injuries in sports with a focus on RTP design.
Material and Methods
Definition of the Study Subjects
The subjects of the study will be all players belonging to the first or B team who suffer a muscle injury diagnosed by magnetic resonance imaging. At the time of injury, they will be randomly assigned to either the control group (following a regressive RTP design) or the intervention group (following a progressive RTP design). Masking will be double-blind. The sample size will be N=74.
The secondary variables will be recorded in the database after diagnosis by MRI. Subsequently, the primary variables will be measured and recorded at the beginning, middle, and end of the RTP period.
It is estimated that approximately half of the necessary sample size has been reached: about 37 subjects with muscle injury. The first statistical analysis will then be carried out to observe the preliminary results.
After three years, once the analysis has been completed, the results and conclusions will be written up for publication in a journal.
Detailed description
Capturing and Recruiting Participants
Since the players are from the same club and suffer muscle injuries, they will be included in the control and intervention groups for three years. The following section will explain that the sampling technique is consecutive and that participants can take part in the study several times, as long as they have a muscle injury diagnosed by resonance. Relapses of the same injury or injuries in the same or different muscle groups will also be included in the sample. The head of the club's medical service and collaborating researcher, Dr. José María Villalón Alonso, will recruit the participants. After the diagnostic test (MRI) is performed and the diagnosis and prognosis are established, the participants will be handed over to the recovery specialists, who will design the RTP. The specialists and the participants (players) will be blinded in the same way.
Allocation Procedure/Randomization
Subjects (muscle injuries) have the same probability (50%) of being allocated to the control or intervention group, regardless of previous allocations.
Justification of Sample Size
A type of consecutive sampling will be carried out based on the average probability that a soccer player will suffer a muscular injury. On average, each player will suffer 0.6 muscular injuries per season. In a team of 25 soccer players, this translates to an average of 15 muscular injuries per season. By contrasting this data with the club's database, we can verify the accuracy of this estimate. According to this statistical data, the population from which we will extract the sample will be the total number of muscle injuries suffered by the two teams of Club Atlético Madrid over three years:
0.6 (injuries) x 50 (players) x 3 years = 90 muscle injuries. Using the Grammo sample calculator with a relative error of 5% and a 95% confidence interval, we will calculate the necessary sample size for the sample to be representative, which will be N = 74.
Statistical Analysis Plan:
Phase 1: Use Levene's test to check if the variances of the control and intervention groups are equal.
Phase 2: Use a t-test to determine if there is a significant difference between the means of the control and intervention groups, and to establish whether the null hypothesis (H0) or the alternative hypothesis (HA) is true.
Phase 3: Perform a bivariate study of the relationship between anxiety (dependent variable) and estimated prognosis (independent variable) using Pearson's correlation coefficient.
Phase 4: Conduct a multivariate study through multiple regression between the dependent variable, sleep quality, and the independent variables, age, type of affected tissue, and cortisol level.
Phase 5: Perform a multivariate study through simple linear regression between the dependent variable, anxiety, and the independent variable, previous injuries in the same musculature.
Ethical and Legal Aspects:
Compliance with the standards of Good Clinical Practice, the Declaration of Helsinki, the Oviedo Convention, and the Personal Data Protection and Guarantee of Digital Rights Act (LO 3/2018, December 5, 2018), as well as the regulations for managing clinical histories.
The investigator undertakes to comply with the aforementioned rules throughout the development of the research protocol, as well as in the presentation to this ethics committee, for which the investigator must provide a certificate of Good Clinical Practice (GCP). The collaborating investigators also have this GCP certificate.
Informed Consent Form:
The patient information sheet and informed consent form are both attached in Annexes 1 and 2.
The confidentiality of information collected in the context of the study is guaranteed.
Data Controller: Óscar Vicente Rodríguez TLF: 699 874 059 Email: oscarvicente90@gmail.com
Purpose of data collection: Clinical and epidemiological research.
Maximum period of data retention: The data will be kept for four years (three years for the duration of the study and one extra year for future research).
Processing, communicating, and transferring the personal data of all participating subjects will comply with the provisions of Organic Law 3/2018 of December 5 on the protection of personal data and the guarantee of digital rights.
In accordance with the aforementioned legislation, you may exercise your rights of access, rectification, deletion, opposition, and limitation of data processing. You may also transfer your data to an authorized third party (portability). For these requests, please contact the principal investigator responsible for processing at oscarvicente90@gmail.com or C/Moreno Torroba 10, 1o B, CP. 28220 Majadahonda, Madrid.
The data will be computerized and incorporated into an automated personal data system that complies with all security measures for restricted access, as described in this document.
To guarantee the confidentiality of the obtained information:
Your data and the sample will be identified by a code, and only the study physician and their collaborators will be able to relate this data to you and your medical history. Therefore, your identity will not be disclosed to anyone except in case of medical emergency or legal or administrative requirement.
Only the essential data necessary for the study will be transmitted to third parties and other countries. In no case will the data contain information that can directly identify you, such as your name, initials, address, or social security number. If this transfer occurs, it will be for the aforementioned study purposes and will guarantee confidentiality with at least the level of protection guaranteed by the legislation in force in our country.
Access to your personal information will be restricted to the study physiotherapist, collaborators, health authorities, the Balearic Islands Research Ethics Committee, and authorized personnel when required to verify the study's data and procedures, always maintaining confidentiality in accordance with current legislation.
You may contact the Spanish Data Protection Agency with any claims related to the processing of your personal data.
The handling of biological samples will be in accordance with Law 14/2007 and Royal Decree 1716/2011.
Saliva samples to determine cortisol levels will be collected at the Ciudad Deportiva Atlético de Madrid clinic on three occasions: at the beginning of the RTP, after the magnetic resonance imaging diagnosis, halfway through the established prognosis, and the day before the RTP ends. The analysis will be performed at the same clinic, where, at the end of the cortisol measurement, the saliva will be discarded and only the recorded cortisol value will be kept.
Any risks associated with the procedure used to collect these samples are covered by the study insurance.
The sample will be coded and treated confidentially throughout this study. A code will be used to link the sample to you, and only the investigator and his staff will be able to decipher it to preserve your identity.
If additional data or samples are needed, your physical therapist will contact you to request your cooperation.
You will be informed of the reasons and asked again for your consent if necessary.
It will not receive any economic benefits from the donation of samples or the transfer of provided data, nor will it have any rights to possible commercial benefits from discoveries resulting from the research.
The samples will be analyzed in the Ciudad Deportiva Atlético de Madrid laboratory and stored for four years in case additional analyses related to the study's objectives are necessary. The person responsible for the samples will be the study promoter during this process.
At the end of the research period, your sample may be:
- Destroyed
- Anonymized (i.e., the link between the sample and you will be completely destroyed so that neither the researcher nor any other team member will be able to identify to whom your sample belongs again).
- Incorporated into a collection managed by researcher Óscar Vicente Rodríguez at the Ciudad Deportiva Atlético de Madrid so that it can continue to be used in the "Stress and Muscle Injury" study and line of research. ́
Samples are stored in the Ciudad Deportiva Atlético de Madrid biobank for use in other research projects, which may be unrelated to the initial study for which consent was given. The biobank may provide samples to authorized projects, including those abroad, with prior approval from the scientific and ethics committees. You may contact the biobank to obtain information on projects in which your samples were used.
Insurance Policy or Justification of Absence for Experimental Studies
Mr. Óscar Vicente Rodríguez is the principal investigator and has the following identification number: 35.572.548, and is a member with no. 1224, is registered in the Collective Policy of Professional Civil Responsibility, to which the Official College of Physiotherapists of the Balearic Islands adheres, with number 531000009 from A.M.A. (Agrupación Mutual Aseguradora - La Mutua de los Profesionales Sanitarios). Annex 3.
Commitment to publishing the results
The principal investigator is committed to publishing the results, regardless of their nature, since there is no conflict of interest. This trial will be part of the doctoral student's (principal investigator) thesis, which guarantees the publication of the results to improve the design of the RTP process.
Financial report and source of financing
The project has no private funding other than the 3,235.45 euros provided by PI Oscar Vicente Rodriguez for the cortisol ELISA measurement kits, Oura rings, and tablets used to record expenses. The MRI and radiological report expenses are free for the club due to the entity's nature, with no conflict of interest. The same applies to the team of statisticians who can analyze the results. They are part of the UIB and collaborate with doctoral theses. This essay is one such work. Regarding the CEIm of the Balearic Islands, this trial is exempt from fees (see the documentation), as it is part of the UIB's Doctoral School studies.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, care provider)
- Number of arms
- 2
- Model description
- This is a randomized, double-blind, single-center controlled clinical trial. There will be two groups: a control group and an intervention group. The study will be carried out in the work environment of the principal investigator and doctoral student at the University of the Balearic Islands (UIB) and Club Atlético de Madrid. The study will focus on the first and B teams, which are based at the Ciudad Deportiva del Cerro del Espino in Majadahonda, Madrid. The study will be included in the principal investigator's doctoral thesis.
| Arm | Type | Receives |
|---|---|---|
| Intervention Group | Active comparator | Other: Return to play program with progressive designThe intervention group: Subjects with muscle injuries who are assigned to this group will follow a return-to-play program with a progressive design. |
| Control Group | Experimental | Other: Return to play program with regressive designControl Group: The subjects (muscle injuries) that are assigned to this group will follow a Return to Play program with regressive design. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Male soccer players.
- Diagnosed with a muscle injury via magnetic resonance imaging (MRI) during the three year study period.
- They will all belong to the same club.
- Age will be between 18 and 40 years old.
Key exclusion criteria (2 listed)
- Patients (Muscle injuries) that do not cause players to miss training or competitions.
- Patients voluntarily decide not to participate in the study or abandon the RTP process due to transfers or other exceptional causes.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Return to play program with progressive designAlso: IGThis design has more open objectives than the regressive design. In the progressive design, the duration of the return-to-play program is not determined by a future date, but rather by the player's daily progress. This design is less commonly used for scheduling tasks and planning work. It is intended to be compared with the regressive design to determine which is more appropriate. | Other | Intervention Group |
| Return to play program with regressive designAlso: CGControl Group: Subjects with muscle injuries assigned to this group will follow a Return to Play program with a regressive design. This design has fixed times and objectives from the beginning of the program to predict the athlete's exact discharge time. This design is commonly used for scheduling tasks and planning work. It is intended to evaluate the benefits and drawbacks of the design and compare them with those of the progressive design to determine which is more appropriate. | Other | Control Group |
Primary outcome
Anxiety
Time frame: It will be measured at the beginning, middle, and end of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Player Anxiety During the Return-to-Play Process. GAD-7 Anxiety scale. This is calculated by assigning scores of 0, 1, 2, and 3 to the response categories, respectively,of "not at all," "several days," "more than half the days," and "nearly every day." GAD-7 total score for the seven items ranges from 0 to 21. 0-4: minimal anxiety 5-9: mild anxiety 10-14: moderate anxiety 15-21: severe anxiety
Sleep quality
Time frame: It will be measured at the beginning, middle, and end of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
The quality of the player's sleep during the Return to Play process. This is measured with the Oura Ring, which uses a validated scale to quantify sleep quality. Oura's Sleep Score. 85-100: Optimal sleep quality. 70-84: Good sleep quality. 60-69: Fair sleep quality. 0-59: Areas for improvement are needed.
Stress (cortisol)
Time frame: It will be measured at the beginning, middle, and end of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Stress (cortisol) during the return-to-play process. We will measure it with the ELISA salivary kit to see how this hormone, which is directly related to the stress experienced by the athlete, varies. Cortisol levels are typically measured in micrograms per deciliter (mcg/dL) and fluctuate throughout the day, with the highest levels in the morning and the lowest at night. Normal ranges vary depending on the time of day and the testing method (blood, urine, or saliva), but generally, a healthy individual will have cortisol levels between 10-20 mcg/dL in the early morning (6-8 am) and 3-10 mcg/dL around 4 pm
Heart Rate Variability
Time frame: It will be measured at the beginning, middle, and end of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Player Heart Rate Variability During the Return-to-Play Process. Ouraring device. Interpreting HRV Scores: High HRV (e.g., 70 or higher): Associated with good health, a balanced autonomic nervous system, and better adaptability. Moderate HRV (e.g., 50-70): May indicate a need for improvement in areas like sleep, stress management, or nutrition. Low HRV (e.g., below 50): May indicate increased risk of health problems and a need for addressing underlying issues.
6 secondary outcomes
Age
Time frame: It will be measured and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
History of previous muscle injuries in the same muscle.
Time frame: It will be determined and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Type of tissue involved in the muscle injury.
Time frame: It will be determined and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
The estimated medical prognosis of the player's discharge.
Time frame: It will be determined and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Weight
Time frame: It will be measured and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Height
Time frame: It will be measured and registered in the data base at the beginning of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Jun 2025.
- Results publication: PubMed 32024646Orchard JW, Chaker Jomaa M, Orchard JJ, Rae K, Hoffman DT, Reddin T, Driscoll T. Fifteen-week window for recurrent muscle strains in football: a prospective cohort of 3600 muscle strains over 23 years in professional Australian rules football. Br J Sports Med. 2020 Sep;54(18):1103-1107. doi: 10.1136/bjsports-2019-100755. Epub 2020 Feb 5.
- Results publication: PubMed 28966376Dhillon H, Dhillon S, Dhillon MS. Current Concepts in Sports Injury Rehabilitation. Indian J Orthop. 2017 Sep-Oct;51(5):529-536. doi: 10.4103/ortho.IJOrtho_226_17.
- Results publication: PubMed 31469710Dattilo M, Antunes HKM, Galbes NMN, Monico-Neto M, DE Sa Souza H, Dos Santos Quaresma MVL, Lee KS, Ugrinowitsch C, Tufik S, DE Mello MT. Effects of Sleep Deprivation on Acute Skeletal Muscle Recovery after Exercise. Med Sci Sports Exerc. 2020 Feb;52(2):507-514. doi: 10.1249/MSS.0000000000002137.
- Results publication: PubMed 35906800Tabor J, La P, Kline G, Wang M, Bonfield S, Machan M, Wynne-Edwards K, Emery C, Debert C. Saliva Cortisol as a Biomarker of Injury in Youth Sport-Related Concussion. J Neurotrauma. 2023 Feb;40(3-4):296-308. doi: 10.1089/neu.2022.0190. Epub 2022 Sep 21.
- Results publication: PubMed 36211933Gomez-Espejo V, Olmedilla A, Abenza-Cano L, Garcia-Mas A, Ortega E. Psychological readiness to return to sports practice and risk of recurrence: Case studies. Front Psychol. 2022 Sep 23;13:905816. doi: 10.3389/fpsyg.2022.905816. eCollection 2022.
- Results publication: PubMed 16278548Orchard J, Best TM, Verrall GM. Return to play following muscle strains. Clin J Sport Med. 2005 Nov;15(6):436-41. doi: 10.1097/01.jsm.0000188206.54984.65.
- Results publication: PubMed 38484764Hoy MK, Stache S Jr, Roedl JB. Hamstring Injuries: A Paradigm for Return to Play. Semin Musculoskelet Radiol. 2024 Apr;28(2):119-129. doi: 10.1055/s-0043-1778027. Epub 2024 Mar 14.
- Results publication: PubMed 25742905Wong S, Ning A, Lee C, Feeley BT. Return to sport after muscle injury. Curr Rev Musculoskelet Med. 2015 Jun;8(2):168-75. doi: 10.1007/s12178-015-9262-2.
- Results publication: PubMed 20332509Schulz KF, Altman DG, Moher D; CONSORT Group. CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials. BMJ. 2010 Mar 23;340:c332. doi: 10.1136/bmj.c332.
- Results publication: PubMed 25031367Pollock N, James SL, Lee JC, Chakraverty R. British athletics muscle injury classification: a new grading system. Br J Sports Med. 2014 Sep;48(18):1347-51. doi: 10.1136/bjsports-2013-093302. Epub 2014 Jul 16.
- Results publication: PubMed 16855067Hagglund M, Walden M, Ekstrand J. Previous injury as a risk factor for injury in elite football: a prospective study over two consecutive seasons. Br J Sports Med. 2006 Sep;40(9):767-72. doi: 10.1136/bjsm.2006.026609. Epub 2006 Jul 19.
- Results publication: PubMed 21474377Papacosta E, Nassis GP. Saliva as a tool for monitoring steroid, peptide and immune markers in sport and exercise science. J Sci Med Sport. 2011 Sep;14(5):424-34. doi: 10.1016/j.jsams.2011.03.004. Epub 2011 Apr 7.
- Muscle injury guide Return to play management from Football Club BarcelonaLink provided by the sponsor.
- Return to play following injuries in pro football: insights into the real-life practices,progression strategies and reintegration processesLink provided by the sponsor.
- A Return-to-Performance Pathway for Professional SoccerLink provided by the sponsor.
- How to Deal with Anxiety Around Return to PlayLink provided by the sponsor.
- Mentally Preparing Athletes to Return to Play Following InjuryLink provided by the sponsor.
- Cortisol and Stress recovery in handball teamLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. As part of a doctoral program's research plan, this essay's IPD will be shared with the thesis directors. The IPD is confidential and is only for this research.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Olga Velasco, Phd Physio study director
University of Balearic Islands
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Return to play program with progressive design and Return to play program with regressive design in people with Muscle Injuries and Football Players, run by Universitat de les Illes Balears at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 18 Jun 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Oscar Vicente, PhD Stud. (+34 699 874 059, oscarvicente90@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Anxiety (time frame: It will be measured at the beginning, middle, and end of the return-to-play process. This will be done for all subjects (muscle injuries) included in the study during the three years of the trial.). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07012408, which also lists 30 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Jun 2025; AzTrials last refreshed its copy on 8 Nov 2026.