ACL InjuryHemoNIRS-LCANCT06621355
A Paradigm Shift in Musculoskeletal Rehabilitation Assessment After ACL Reconstruction Using Near-Infrared Spectroscopy
An observational study of ACL Injury and Hemodynamics, run by Universitat de Lleida at 1 site in Spain.
Trial summary
This study aims to establish and compare muscle haemodynamic response patterns in physically active subjects with anterior cruciate ligament (ACL) reconstruction, at different time points after surgery, against healthy controls, using 24 non-invasive near-infrared spectroscopy (NIRS) devices simultaneously during a… Read more about this study
- Who is it for?
- Ages 18 to 65 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- ACL Injury, Hemodynamics, Oxygen Consumption Based Assessment of Hemodynamics
- What is being tested?
- Incremental Interval Test on a Cycle Ergometer
- How many people
- 129 participants
- Where
- 1 siteSpain
- Study dates
- 1 Oct 2026to 30 Dec 2026
- Phase
- Observational
- 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 65 years
- Men only
- Healthy volunteers accepted
- Adult, Older adult
Study population: Participants are recruited from four collaborating centres in Mallorca: Espai Físic de Salut Integral, Fisioplanet, Hospital Universitari Son Espases (HUSE), and Sant Joan de Déu Palma-Inca (SJD), coordinated by the Universitat de Lleida (UdL). The sample is a non-probability convenience sample of men aged 18 to 65 years, allocated to three groups. LCA1: recent post-surgical ACL reconstruction, up to 6 months since surgery, referred by the physiotherapist or rehabilitation physician responsible for their recovery. LCA2: long-term post-surgical ACL reconstruction, at least 2 years since surgery, currently physically active, identified retrospectively from clinical databases at the collaborating centres. CON: healthy controls with no history of ACL or meniscal injury, recruited among people attending the collaborating centres for general fitness training, who are also regularly physically active.
General inclusion criteria
- Men aged 18 to 65 years.
- Adipose tissue thickness of less than 2 cm at the NIRS device placement sites, assessed with a skinfold calliper.
- Functional capacity to complete an incremental interval test on a cycle ergometer.
- Able to understand and communicate, both orally and in writing, in Spanish, Catalan or English.
General exclusion criteria
- Cardiometabolic, endocrine, neurological, or other severe comorbidity that could compromise participant safety, alter physical performance, or interfere with the interpretation of the results.
- Disabling pain preventing completion of the physical assessment as established in the protocol.
Eligibility criteria (LCA1 group)
- Physically active before the injury, with an exercise frequency greater than 3 days per week.
- Surgically treated with ACL reconstruction.
- Time since surgery of 6 months or less.
- Explicit authorisation from the physiotherapist or rehabilitation physician responsible for their recovery, confirming that the participant is able to safely tolerate the physical demands of the test.
Eligibility criteria (LCA2 group)
- History of ACL reconstruction surgery, with a minimum of 2 years since the intervention.
- Regular physical exercise practice (more than 3 days per week) during at least the 2 to 3 months prior to assessment.
Eligibility criteria (CON group)
- Regular physical exercise practice (more than 3 days per week) during at least the 2 to 3 months prior to assessment.
- No history of ACL injury or meniscal injury in either knee.
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
Espai Físic de Salut Integral (Sant Agustí)
Palma de Mallorca, Balearic Islands, 07015
Francisco J Verdejo-Amengual, +34 973702459, xisco.verdejo@udl.cat
Francisco J Verdejo-Amengual
About this study
Official title: A Paradigm Shift in the Assessment of Musculoskeletal Rehabilitation After Anterior Cruciate Ligament Reconstruction: Protocol for a Multicenter Case-Control Cross-Sectional Study Using Near-Infrared Spectroscopy (HemoNIRS-LCA)
This study aims to establish and compare muscle haemodynamic response patterns in physically active subjects with anterior cruciate ligament (ACL) reconstruction, at different time points after surgery, against healthy controls, using 24 non-invasive near-infrared spectroscopy (NIRS) devices simultaneously during a single incremental interval cycling test.
Muscle haemodynamics has so far been assessed using at most 2-3 near-infrared spectroscopy devices on isolated muscles and without correlating variables. At the same time, research on musculoskeletal pathologies is limited, and there are no studies that analyse the haemodynamic changes that occur when the anterior cruciate ligament (ACL) is injured and whether these changes last over time.
This is a multicentre, observational, case-control, cross-sectional study, approved by the Clinical Research Ethics Committee of the Arnau de Vilanova University Hospital (CEIC-3203), that will include males aged 18-65 years who have undergone ACL reconstruction, divided into three groups: less than 6 months since surgery (ACL1), more than 2 years since surgery with normalised physical activity (ACL2), and a healthy control group with no history of ACL injury. Recruitment has not yet started and is expected to begin in October 2026
Read the detailed description
Assessment of muscle haemodynamics after musculoskeletal injury has traditionally relied on a limited number of near-infrared spectroscopy (NIRS) sensors placed on isolated muscles, without a simultaneous, multi-site approach. This study addresses that methodological gap in the context of anterior cruciate ligament (ACL) reconstruction.
This study aims to establish and compare muscle haemodynamic response patterns, measured using NIRS, in physically active individuals with ACL reconstruction at different time points after surgery, compared with healthy controls.
It is a multicentre, observational, case-control, cross-sectional study, conducted in three groups of males aged 18 to 65 years: ACL1 (less than 6 months since ACL reconstruction), ACL2 (more than 2 years since ACL reconstruction, with normalised physical activity and no longer undergoing rehabilitation), and a healthy control group with no history of ACL injury.
Each participant completes a single incremental interval cycling test on a cycle ergometer. During the test, 24 portable NIRS devices (Moxy) simultaneously and bilaterally record haemodynamic data at 12 muscle locations: rectus femoris (proximal and distal thirds), vastus medialis, vastus lateralis, biceps femoris (proximal and distal thirds), semitendinosus, gluteus maximus, tibialis anterior, gastrocnemius, medial deltoid, and biceps brachii; combining propulsive, stabilising, and postural musculature and reflecting a multi-joint, whole-body approach to the assessment of exercise-induced muscle haemodynamics.. Data are analysed using a proprietary multiparametric interpretation algorithm designed to evaluate the haemodynamic performance of multiple muscle groups simultaneously and comparatively. Assessors and statisticians remain blinded to group assignment throughout data collection and analysis.
Primary outcomes are muscle oxygen saturation, capillary haemoglobin concentration, and muscle blood flow, recorded continuously via NIRS at each of the 12 bilateral locations during exercise and through 2 to 3 minutes of post-exercise recovery (an individually variable recovery period). Secondary outcomes include heart rate (continuous Bluetooth monitoring), rating of perceived exertion (Borg CR-10 scale, 0-10), anthropometric and adiposity indicators (height, weight and body mass index), sociodemographic and clinical variables (age, toxic habits, injury and sports history, and physical activity in the preceding 48 to 72 hours), and study dropouts with their reason.
Sample size was calculated using G-Power, based on a moderate effect size (Cohen's d = 0.5) estimated from a study in the process of publication, with a 95% confidence level (Z = 1.96), 80% statistical power (β = 0.20), and a 10% non-response rate, yielding a required sample of 43 participants per group (total n = 129).
The study is conducted at four collaborating centers: Espai Físic de Salut Integral, Fisioplanet, Hospital Universitari Son Espases (HUSE), and Sant Joan de Déu Palma-Inca (SJD). It is approved by the Clinical Research Ethics Committee of the Arnau de Vilanova University Hospital (CEIC-3203)
- Conditions
- ACL Injury, Hemodynamics, Oxygen Consumption Based Assessment of Hemodynamics, Exercise, Anterior Cruciate Ligament Reconstruction
- Being tested
- Incremental Interval Test on a Cycle Ergometer
- Keywords
- Spectroscopy, Near-Infrared, Hemodynamics, Exercise, Vascular resistance, Oxygen consumption, Case-Control Studies, Cross-Sectional Studies
- Medical subject headings
- Anterior Cruciate Ligament Injuries, Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Incremental Interval Test on a Cycle ErgometerDiagnostic test
Also called Fitness assessment test, Physical test
Participants perform a single incremental interval test on a cycle ergometer: 4 minutes of exercise followed by 1 minute of rest, at an individual intensity below the anaerobic threshold. All participants begin at the same initial load of 50 watts, increased at the end of each rest minute in steps of 25 watts, until the participant is unable to complete a full interval; this final incomplete interval is also recorded and analysed. During the rest minute, participants must remain completely still, without moving any part of the body; at the end of each 4-minute work period, the assessor counts down so the participant can prepare for the next interval. Throughout the test, 24 near-infrared spectroscopy (NIRS) devices are placed bilaterally over 12 muscle sites: rectus femoris (proximal and distal thirds), vastus medialis, vastus lateralis, biceps femoris (proximal and distal thirds), semitendinosus, gluteus maximus, tibialis anterior, gastrocnemius, medial deltoid, and biceps brachii.
| Study group | Role | What they receive |
|---|---|---|
| LCA1 | Participants who underwent ACL surgical reconstruction no more than 6 months before assessment and are at a stage of recovery that allows them to safely perform and tolerate the physical test. Receives: Diagnostic Test: Incremental Interval Test on a Cycle Ergometer | |
| LCA2 | Participants with a history of ACL surgical reconstruction at least 2 years before assessment, who have maintained regular physical activity, are no longer undergoing rehabilitation, and are able to perform and tolerate the same physical test as the LCA1 group Receives: Diagnostic Test: Incremental Interval Test on a Cycle Ergometer | |
| CON | Healthy participants with no history of ACL or meniscal injury, matched by regular physical activity to the other study groups, and able to perform and tolerate the same physical test as the LCA1 group Receives: Diagnostic Test: Incremental Interval Test on a Cycle Ergometer |
What is being measured
The primary outcome is the main question the study is designed to answer.
Muscular Oxygen Saturation (SmO2 - %)
Percentage of oxygen-loaded haemoglobin and myoglobin at the muscular capillary level, recorded via NIRS at 0.5-second intervals.
Measured: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minu
Absolute Capillary Haemoglobin (ThB - g/dL)
Grams of oxygen-loaded and oxygen-depleted haemoglobin and myoglobin per deciliter of blood captured by the devices at the muscular capillary level, recorded via NIRS at 0.5-second intervals.
Measured: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics.
Oxygen-loaded capillary haemoglobin (O2HHb - g/dL)
Grams of oxygen-loaded haemoglobin and myoglobin per decilitre of blood captured by the devices at the muscular capillary level, recorded via NIRS at 0.5-second intervals.
Measured: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics.
Capillary Haemoglobin Oxygen Depleted (HHb - g/dL)
Grams of oxygen-depleted haemoglobin and myoglobin per decilitre of blood captured by the devices at the muscular capillary level, recorded via NIRS at 0.5-second intervals.
Measured: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Blood Flow of Relative Muscle Haemoglobin (ThB BF - g/dL/min)
Relative blood flow value of haemoglobin per unit of time circulating through the muscular capillary, calculated by incorporating heart rate values, recorded via NIRS at 0.5-second intervals.
Measured: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Blood Flow of Oxygen Loaded Relative Muscle Haemoglobin (O2HHb BF - g/dL/min)
Relative blood flow value of oxygen-loaded haemoglobin per unit of time circulating through the muscular capillary, calculated by incorporating heart rate values, recorded via NIRS at 0.5-second intervals.
Measured: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Blood Flow of Oxygen Discharged Relative Muscle Haemoglobin (HHb BF - g/dL/min)
Relative blood flow value of oxygen-depleted haemoglobin per unit of time circulating through the muscular capillary, calculated by incorporating heart rate values, recorded via NIRS at 0.5-second intervals
Measured: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Secondary outcomes (5)
Heart Rate (bpm)
Continuous heart rate monitoring throughout the test and post-exercise recovery, using a chest strap heart rate monitor (Garmin HRM-Pro Plus) with Bluetooth transmission to the central data unit.
Measured: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Rating of Perceived Exertion (RPE-10 / Borg CR-10 scale - 0-10)
Subjective perception of physical effort measured using the reduced Borg scale (CR-10), ranging from 0 (no exertion) to 10 (maximum exertion).
Measured: Recorded before the test, during the initial 5-minute calibration period; during the test, at the end of each 4-minute work interval; and immediately at the end of the test.
Anthropometry: Height (m)
Height measured with a standard stadiometer, used together with body weight to calculate body mass index (BMI, kg/m2).
Measured: Baseline, prior to the incremental interval cycling test, recorded once.
Anthropometry: Weight (kg)
Body weight (kg), measured together with height to calculate body mass index (BMI, kg/m2).
Measured: Baseline, prior to the incremental interval cycling test, recorded once.
Sociodemographic and Clinical Variables
Sociodemographic and clinical data collected via a brief questionnaire, including age, toxic habits, injury history, sports history, and physical activity in the preceding 48 to 72 hours.
Measured: Baseline, prior to the incremental interval cycling test, recorded once.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Oct 2024
- Study start1 Oct 2026 (estimated)
- Primary completion30 Dec 2026 (estimated)
- Study completion30 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ACL InjuryStudies 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
- Observational
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Enrolment
- 129 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universitat de Lleida
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Xisco Verdejo, Universitat de Lleida
- Investigators
- Francesc Valenzuela-Pascual, PhD, Study director, Universitat de LleidaOriol Martínez-Navarro, PhD, Study director, Universitat de Lleida
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06621355
- Sponsor's protocol ID
- HemoNIRS-LCA
- Acronym
- HemoNIRS-LCA
- Status last verified
- Sep 2026
- First submitted
- 25 Sep 2024
- Last updated
- 10 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: The plan to share individual participant data (IPD) is pending a final decision, as data interpretation in this study relies on an algorithm that is the subject of an international patent (WO2022013479A9) held by a third party. This intellectual property matter constrains the scope of any future data-sharing plan. Once resolved, the research team will consider making anonymized hemodynamic and sociodemographic data available to qualified researchers upon reasonable request, subject to applicable data protection regulations (EU Regulation 2016/679 and Spanish Organic Law 3/2018).
Study at a glance
From the registry record, last updated by the sponsor on 10 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Paradigm Shift in the Assessment of Musculoskeletal Rehabilitation After Anterior Cruciate Ligament Reconstruction: Protocol for a Multicenter Case-Control Cross-Sectional Study Using Near-Infrared Spectroscopy (HemoNIRS-LCA)
- ClinicalTrials.gov ID
- NCT06621355
- Acronym / sponsor ID
- HemoNIRS-LCA / HemoNIRS-LCA
- Conditions
- ACL Injury, Hemodynamics, Oxygen Consumption Based Assessment of Hemodynamics, Exercise, Anterior Cruciate Ligament Reconstruction
- Keywords
- Spectroscopy, Near-Infrared, Hemodynamics, Exercise, Vascular resistance, Oxygen consumption, Case-Control Studies, Cross-Sectional Studies
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 129 participants (estimated)
- Lead sponsor
- Universitat de LleidaUniversity, hospital or other
- Study start
- 1 Oct 2026 (estimated)
- Primary completion
- 30 Dec 2026 (estimated)
- Study completion
- 30 Dec 2026 (estimated)
- First posted
- 1 Oct 2024 (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.
This study aims to establish and compare muscle haemodynamic response patterns in physically active subjects with anterior cruciate ligament (ACL) reconstruction, at different time points after surgery, against healthy controls, using 24 non-invasive near-infrared spectroscopy (NIRS) devices simultaneously during a single incremental interval cycling test.
Muscle haemodynamics has so far been assessed using at most 2-3 near-infrared spectroscopy devices on isolated muscles and without correlating variables. At the same time, research on musculoskeletal pathologies is limited, and there are no studies that analyse the haemodynamic changes that occur when the anterior cruciate ligament (ACL) is injured and whether these changes last over time.
This is a multicentre, observational, case-control, cross-sectional study, approved by the Clinical Research Ethics Committee of the Arnau de Vilanova University Hospital (CEIC-3203), that will include males aged 18-65 years who have undergone ACL reconstruction, divided into three groups: less than 6 months since surgery (ACL1), more than 2 years since surgery with normalised physical activity (ACL2), and a healthy control group with no history of ACL injury. Recruitment has not yet started and is expected to begin in October 2026
Detailed description
Assessment of muscle haemodynamics after musculoskeletal injury has traditionally relied on a limited number of near-infrared spectroscopy (NIRS) sensors placed on isolated muscles, without a simultaneous, multi-site approach. This study addresses that methodological gap in the context of anterior cruciate ligament (ACL) reconstruction.
This study aims to establish and compare muscle haemodynamic response patterns, measured using NIRS, in physically active individuals with ACL reconstruction at different time points after surgery, compared with healthy controls.
It is a multicentre, observational, case-control, cross-sectional study, conducted in three groups of males aged 18 to 65 years: ACL1 (less than 6 months since ACL reconstruction), ACL2 (more than 2 years since ACL reconstruction, with normalised physical activity and no longer undergoing rehabilitation), and a healthy control group with no history of ACL injury.
Each participant completes a single incremental interval cycling test on a cycle ergometer. During the test, 24 portable NIRS devices (Moxy) simultaneously and bilaterally record haemodynamic data at 12 muscle locations: rectus femoris (proximal and distal thirds), vastus medialis, vastus lateralis, biceps femoris (proximal and distal thirds), semitendinosus, gluteus maximus, tibialis anterior, gastrocnemius, medial deltoid, and biceps brachii; combining propulsive, stabilising, and postural musculature and reflecting a multi-joint, whole-body approach to the assessment of exercise-induced muscle haemodynamics.. Data are analysed using a proprietary multiparametric interpretation algorithm designed to evaluate the haemodynamic performance of multiple muscle groups simultaneously and comparatively. Assessors and statisticians remain blinded to group assignment throughout data collection and analysis.
Primary outcomes are muscle oxygen saturation, capillary haemoglobin concentration, and muscle blood flow, recorded continuously via NIRS at each of the 12 bilateral locations during exercise and through 2 to 3 minutes of post-exercise recovery (an individually variable recovery period). Secondary outcomes include heart rate (continuous Bluetooth monitoring), rating of perceived exertion (Borg CR-10 scale, 0-10), anthropometric and adiposity indicators (height, weight and body mass index), sociodemographic and clinical variables (age, toxic habits, injury and sports history, and physical activity in the preceding 48 to 72 hours), and study dropouts with their reason.
Sample size was calculated using G-Power, based on a moderate effect size (Cohen's d = 0.5) estimated from a study in the process of publication, with a 95% confidence level (Z = 1.96), 80% statistical power (β = 0.20), and a 10% non-response rate, yielding a required sample of 43 participants per group (total n = 129).
The study is conducted at four collaborating centers: Espai Físic de Salut Integral, Fisioplanet, Hospital Universitari Son Espases (HUSE), and Sant Joan de Déu Palma-Inca (SJD). It is approved by the Clinical Research Ethics Committee of the Arnau de Vilanova University Hospital (CEIC-3203)
Study design
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| LCA1 | – | Diagnostic Test: Incremental Interval Test on a Cycle ErgometerParticipants who underwent ACL surgical reconstruction no more than 6 months before assessment and are at a stage of recovery that allows them to safely perform and tolerate the physical test. |
| LCA2 | – | Diagnostic Test: Incremental Interval Test on a Cycle ErgometerParticipants with a history of ACL surgical reconstruction at least 2 years before assessment, who have maintained regular physical activity, are no longer undergoing rehabilitation, and are able to perform and tolerate the same physical test as the LCA1 group |
| CON | – | Diagnostic Test: Incremental Interval Test on a Cycle ErgometerHealthy participants with no history of ACL or meniscal injury, matched by regular physical activity to the other study groups, and able to perform and tolerate the same physical test as the LCA1 group |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Participants are recruited from four collaborating centres in Mallorca: Espai Físic de Salut Integral, Fisioplanet, Hospital Universitari Son Espases (HUSE), and Sant Joan de Déu Palma-Inca (SJD), coordinated by the Universitat de Lleida (UdL). The sample is a non-probability convenience sample of men aged 18 to 65 years, allocated to three groups. LCA1: recent post-surgical ACL reconstruction, up to 6 months since surgery, referred by the physiotherapist or rehabilitation physician responsible for their recovery. LCA2: long-term post-surgical ACL reconstruction, at least 2 years since surgery, currently physically active, identified retrospectively from clinical databases at the collaborating centres. CON: healthy controls with no history of ACL or meniscal injury, recruited among people attending the collaborating centres for general fitness training, who are also regularly physically active.
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 |
|---|---|---|
| Incremental Interval Test on a Cycle ErgometerAlso: Fitness assessment test, Physical testParticipants perform a single incremental interval test on a cycle ergometer: 4 minutes of exercise followed by 1 minute of rest, at an individual intensity below the anaerobic threshold. All participants begin at the same initial load of 50 watts, increased at the end of each rest minute in steps of 25 watts, until the participant is unable to complete a full interval; this final incomplete interval is also recorded and analysed. During the rest minute, participants must remain completely still, without moving any part of the body; at the end of each 4-minute work period, the assessor counts down so the participant can prepare for the next interval. Throughout the test, 24 near-infrared spectroscopy (NIRS) devices are placed bilaterally over 12 muscle sites: rectus femoris (proximal and distal thirds), vastus medialis, vastus lateralis, biceps femoris (proximal and distal thirds), semitendinosus, gluteus maximus, tibialis anterior, gastrocnemius, medial deltoid, and biceps brachii. | Diagnostic test | CON, LCA1, LCA2 |
Primary outcome
Muscular Oxygen Saturation (SmO2 - %)
Time frame: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minu
Percentage of oxygen-loaded haemoglobin and myoglobin at the muscular capillary level, recorded via NIRS at 0.5-second intervals.
Absolute Capillary Haemoglobin (ThB - g/dL)
Time frame: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics.
Grams of oxygen-loaded and oxygen-depleted haemoglobin and myoglobin per deciliter of blood captured by the devices at the muscular capillary level, recorded via NIRS at 0.5-second intervals.
Oxygen-loaded capillary haemoglobin (O2HHb - g/dL)
Time frame: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics.
Grams of oxygen-loaded haemoglobin and myoglobin per decilitre of blood captured by the devices at the muscular capillary level, recorded via NIRS at 0.5-second intervals.
Capillary Haemoglobin Oxygen Depleted (HHb - g/dL)
Time frame: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Grams of oxygen-depleted haemoglobin and myoglobin per decilitre of blood captured by the devices at the muscular capillary level, recorded via NIRS at 0.5-second intervals.
Blood Flow of Relative Muscle Haemoglobin (ThB BF - g/dL/min)
Time frame: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Relative blood flow value of haemoglobin per unit of time circulating through the muscular capillary, calculated by incorporating heart rate values, recorded via NIRS at 0.5-second intervals.
Blood Flow of Oxygen Loaded Relative Muscle Haemoglobin (O2HHb BF - g/dL/min)
Time frame: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Relative blood flow value of oxygen-loaded haemoglobin per unit of time circulating through the muscular capillary, calculated by incorporating heart rate values, recorded via NIRS at 0.5-second intervals.
Blood Flow of Oxygen Discharged Relative Muscle Haemoglobin (HHb BF - g/dL/min)
Time frame: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Relative blood flow value of oxygen-depleted haemoglobin per unit of time circulating through the muscular capillary, calculated by incorporating heart rate values, recorded via NIRS at 0.5-second intervals
5 secondary outcomes
Heart Rate (bpm)
Time frame: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minutes according to each participant's individual recovery kinetics
Rating of Perceived Exertion (RPE-10 / Borg CR-10 scale - 0-10)
Time frame: Recorded before the test, during the initial 5-minute calibration period; during the test, at the end of each 4-minute work interval; and immediately at the end of the test.
Anthropometry: Height (m)
Time frame: Baseline, prior to the incremental interval cycling test, recorded once.
Anthropometry: Weight (kg)
Time frame: Baseline, prior to the incremental interval cycling test, recorded once.
Sociodemographic and Clinical Variables
Time frame: Baseline, prior to the incremental interval cycling test, recorded once.
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 10 Sep 2026.
- Individual participant dataSharing planned: Undecided. The plan to share individual participant data (IPD) is pending a final decision, as data interpretation in this study relies on an algorithm that is the subject of an international patent (WO2022013479A9) held by a third party. This intellectual property matter constrains the scope of any future data-sharing plan. Once resolved, the research team will consider making anonymized hemodynamic and sociodemographic data available to qualified researchers upon reasonable request, subject to applicable data protection regulations (EU Regulation 2016/679 and Spanish Organic Law 3/2018).
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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.
Francesc Valenzuela-Pascual, PhD study director
Universitat de Lleida
Oriol Martínez-Navarro, PhD study director
Universitat de Lleida
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of ACL Injury and Hemodynamics, run by Universitat de Lleida 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?
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 10 Sep 2026. 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 Francisco J. Verdejo-Amengual (+34 670729376, xisco.verdejo@udl.cat), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Muscular Oxygen Saturation (SmO2 - %) (time frame: Continuously during the test and through a minimum 2-minute post-exercise recovery period, extended up to 3 minu). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 10 Sep 2026; AzTrials last refreshed its copy on 26 Oct 2026.