Sports Physical TherapyNCT07373158
Inspiratory Muscle Activation and Post-Exercise Recovery in Professional Football Players
A study testing Inspiratory muscle activation via phrenic nerve modulation and Inspiratory muscle activation via threshold device in people with Sports Physical Therapy and Injury;Sports, run by Sierra Varona SL.
Trial summary
Respiratory muscles play a fundamental role in sports performance. Fatigue of these muscles induces changes in maximal inspiratory pressure and autonomic nervous system activity, thereby compromising the athlete's recovery process. Read more about this study
- Who is it for?
- Ages 18 to 40 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Sports Physical Therapy, Injury;Sports
- What is being tested?
- Inspiratory muscle activation via phrenic nerve modulation and Inspiratory muscle activation via threshold device
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- No sites listed yet
- Study dates
- 20 Jan 2026to 1 Apr 2026
- 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
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male professional football player.
- Currently under an active professional contract and participating in regular competition.
- Aged between 18 and 40 years.
- No participation in inspiratory muscle training (IMT) programs in the past 12 months.
- Signed informed consent provided by the participant.
Who cannot join
- Musculoskeletal injuries or surgical interventions within the past 6 months.
- Use of medications affecting cardiac or respiratory function (e.g., beta-blockers, beta-adrenergic inhibitors).
- Presence of any acute and/or chronic disease (cardiorespiratory, neurological, metabolic, oncological, etc.).
- Use of tobacco, recreational drugs, or stimulant substances.
- Metallic implants in the cervical region.
- Presence of a pacemaker.
- Current participation in other inspiratory muscle training programs.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Acute Modulation of Post-Exercise Recovery Through Inspiratory Muscle Activation in Professional Male Football Players: A Randomized Clinical Trial
Respiratory muscles play a fundamental role in sports performance. Fatigue of these muscles induces changes in maximal inspiratory pressure and autonomic nervous system activity, thereby compromising the athlete's recovery process. The primary aim of this study is to evaluate the specific effects of different inspiratory muscle activation modalities on post-exercise recovery in professional male football players. The study seeks to determine which of the three modalities-bilateral phrenic nerve electrical stimulation, a threshold loading device protocol, or inactivity-provides greater benefits for recovery. The effectiveness of these interventions will be assessed using two key outcome variables: maximal inspiratory pressure (MIP) and heart rate variability (HRV).
This study is designed as a randomized clinical trial (RCT) in which participants will be allocated into three intervention groups: a bilateral phrenic nerve electrical stimulation group (EG1), in which involuntary diaphragmatic contractions will be induced using an electrotherapy device with current applied to the phrenic nerves; a threshold device group (EG2), in which participants will perform breathing against submaximal inspiratory loads equivalent to 40% of their MIP; and a control group (CG), which will remain seated for a period equivalent to the duration of the other interventions. Group allocation will be ensured through randomization using Microsoft Excel.
Regarding statistical analysis, data normality will be assessed using the Shapiro-Wilk test. Comparisons of quantitative variables will be performed using Student's t test when normality assumptions are met, or the Mann-Whitney U test otherwise. A p value < 0.05 will be considered statistically significant.
- Conditions
- Sports Physical Therapy, Injury;Sports
- Being tested
- Inspiratory muscle activation via phrenic nerve modulation, Inspiratory muscle activation via threshold device
- Medical subject headings
- Athletic Injuries
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Inspiratory muscle activation via phrenic nerve modulationDevice
Phrenic nerve stimulation using low-frequency symmetric biphasic current
Inspiratory muscle activation via threshold deviceDevice
Deep inspirations against submaximal inspiratory load
| Study group | Role | What they receive |
|---|---|---|
| Phrenic Electrostimulation | Experimental | The participant will be placed in the supine position, and the intervention will be performed using a pen-type electrode. Bilateral stimulation of the phrenic nerves will be applied below the sternal portion of the sternocleidomastoid muscle at the C3-C5 level. The electrical stimulators will be set to a mean frequency of 50 Hz and a pulse width of 300 μs. Stimulation intensity will be progressively increased until a visible diaphragmatic contraction (abdominal movement) is observed and reaches the maximum level tolerable for the player.
The stimulation protocol will consist of two sets of 30 repetitions, delivered in bilateral cycles of 6 s ON (stimulation) and 10 s OFF (rest), including a 2-minute rest period between sets. Concurrently with the perception of the involuntary contraction, the participant will perform a voluntary contraction through diaphragmatic inspiration. Receives: Device: Inspiratory muscle activation via phrenic nerve modulation |
| Inspiratory muscle warm-up group | Active comparator | Participants will breathe against submaximal inspiratory loads following a protocol consisting of two sets of 30 breaths, equivalent to 40% of their MIP, using the Breathcare MIP/MEP device (Big Breathe®, GH Innotek Co., Ltd., Busan, Republic of Korea). Breathing will be performed using a self-paced pattern, provided that a ratio of approximately 1 s of inspiration to 2 s of expiration is maintained to avoid hyperventilation.
The session duration will correspond to the exact time required to complete the two sets of breaths, including a 2-minute rest period between sets, with an estimated total duration of approximately 15 minutes. Receives: Device: Inspiratory muscle activation via threshold device |
| Control group | No intervention | Participants in this group will remain seated at rest in a quiet and controlled environment. During this period, they will breathe normally. The rest duration for this group will be identical to that of the other interventions. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Hear rate variability
HRV will be assessed using a heart rate monitor (Polar H10; Polar Electro Oy, Kempele, Finland) with participants in the supine position in a quiet room (~25 °C, dim lighting). Cardiac signals will be recorded for 3 minutes via a chest strap. Participants will avoid caffeine, alcohol, tobacco, and intense exercise for 12 h prior, and refrain from speaking or voluntary movements during recording. Analysis will be performed with Kubios HRV 3.1.0 (University of Kuopio, Finland), examining LF/HF ratio, LF (0.04-0.15 Hz) and HF (0.15-0.40 Hz) power in normalized units, SDNN, and RMSSD.
Measured: Pre-match 24 hours before (baseline); Post-match 24 hours (pre-intervention); Immediately post-intervention; 15 minutes post-intervention; 30 minutes post-intervention
Secondary outcomes (1)
Maximal Inspiratory Pressure
Maximal inspiratory pressure (MIP) will be assessed with participants in a seated position using the Breathcare MIP/MEP device (Big Breathe®, GH Innotek Co., Ltd., Busan, Republic of Korea). The examiner will demonstrate the maneuver prior to its execution. To ensure proper airflow through the mouth, the nostrils will be occluded. Participants will perform up to six maneuvers per attempt, with a 1-minute rest between each. The most consistent and reproducible result from three attempts, with a variation of less than 5%, will be selected for analysis.
Measured: Pre-match 24 hours before (baseline); Post-match 24 hours (pre-intervention); Immediately post-intervention; 15 minutes post-intervention; 30 minutes post-intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Jan 2026
- Study start20 Jan 2026 (estimated)
- Primary completion10 Mar 2026 (estimated)
- Study completion1 Apr 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Sports Physical TherapyStudies 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
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Sierra Varona SL
- Sponsor type
- University, hospital or other
- Collaborators
- University of Alcala
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07373158
- Sponsor's protocol ID
- 021
- Status last verified
- Jan 2026
- First submitted
- 8 Jan 2026
- Last updated
- 28 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The availability of the data, and the materials will be available at the request of the publisher.
Study at a glance
From the registry record, last updated by the sponsor on 28 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Acute Modulation of Post-Exercise Recovery Through Inspiratory Muscle Activation in Professional Male Football Players: A Randomized Clinical Trial
- ClinicalTrials.gov ID
- NCT07373158
- Acronym / sponsor ID
- 021
- Conditions
- Sports Physical Therapy, Injury;Sports
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Sierra Varona SLUniversity, hospital or other
- Collaborators
- University of Alcala
- Study start
- 20 Jan 2026 (estimated)
- Primary completion
- 10 Mar 2026 (estimated)
- Study completion
- 1 Apr 2026 (estimated)
- First posted
- 28 Jan 2026 (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.
Respiratory muscles play a fundamental role in sports performance. Fatigue of these muscles induces changes in maximal inspiratory pressure and autonomic nervous system activity, thereby compromising the athlete's recovery process. The primary aim of this study is to evaluate the specific effects of different inspiratory muscle activation modalities on post-exercise recovery in professional male football players. The study seeks to determine which of the three modalities-bilateral phrenic nerve electrical stimulation, a threshold loading device protocol, or inactivity-provides greater benefits for recovery. The effectiveness of these interventions will be assessed using two key outcome variables: maximal inspiratory pressure (MIP) and heart rate variability (HRV).
This study is designed as a randomized clinical trial (RCT) in which participants will be allocated into three intervention groups: a bilateral phrenic nerve electrical stimulation group (EG1), in which involuntary diaphragmatic contractions will be induced using an electrotherapy device with current applied to the phrenic nerves; a threshold device group (EG2), in which participants will perform breathing against submaximal inspiratory loads equivalent to 40% of their MIP; and a control group (CG), which will remain seated for a period equivalent to the duration of the other interventions. Group allocation will be ensured through randomization using Microsoft Excel.
Regarding statistical analysis, data normality will be assessed using the Shapiro-Wilk test. Comparisons of quantitative variables will be performed using Student's t test when normality assumptions are met, or the Mann-Whitney U test otherwise. A p value < 0.05 will be considered statistically significant.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Phrenic Electrostimulation | Experimental | Device: Inspiratory muscle activation via phrenic nerve modulationThe participant will be placed in the supine position, and the intervention will be performed using a pen-type electrode. Bilateral stimulation of the phrenic nerves will be applied below the sternal portion of the sternocleidomastoid muscle at the C3-C5 level. The electrical stimulators will be set to a mean frequency of 50 Hz and a pulse width of 300 μs. Stimulation intensity will be progressively increased until a visible diaphragmatic contraction (abdominal movement) is observed and reaches the maximum level tolerable for the player. The stimulation protocol will consist of two sets of 30 repetitions, delivered in bilateral cycles of 6 s ON (stimulation) and 10 s OFF (rest), including a 2-minute rest period between sets. Concurrently with the perception of the involuntary contraction, the participant will perform a voluntary contraction through diaphragmatic inspiration. |
| Inspiratory muscle warm-up group | Active comparator | Device: Inspiratory muscle activation via threshold deviceParticipants will breathe against submaximal inspiratory loads following a protocol consisting of two sets of 30 breaths, equivalent to 40% of their MIP, using the Breathcare MIP/MEP device (Big Breathe®, GH Innotek Co., Ltd., Busan, Republic of Korea). Breathing will be performed using a self-paced pattern, provided that a ratio of approximately 1 s of inspiration to 2 s of expiration is maintained to avoid hyperventilation. The session duration will correspond to the exact time required to complete the two sets of breaths, including a 2-minute rest period between sets, with an estimated total duration of approximately 15 minutes. |
| Control group | No intervention | –Participants in this group will remain seated at rest in a quiet and controlled environment. During this period, they will breathe normally. The rest duration for this group will be identical to that of the other interventions. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Male professional football player.
- Currently under an active professional contract and participating in regular competition.
- Aged between 18 and 40 years.
- No participation in inspiratory muscle training (IMT) programs in the past 12 months.
- Signed informed consent provided by the participant.
Key exclusion criteria (7 listed)
- Musculoskeletal injuries or surgical interventions within the past 6 months.
- Use of medications affecting cardiac or respiratory function (e.g., beta-blockers, beta-adrenergic inhibitors).
- Presence of any acute and/or chronic disease (cardiorespiratory, neurological, metabolic, oncological, etc.).
- Use of tobacco, recreational drugs, or stimulant substances.
- Metallic implants in the cervical region.
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 |
|---|---|---|
| Inspiratory muscle activation via phrenic nerve modulationPhrenic nerve stimulation using low-frequency symmetric biphasic current | Device | Phrenic Electrostimulation |
| Inspiratory muscle activation via threshold deviceDeep inspirations against submaximal inspiratory load | Device | Inspiratory muscle warm-up group |
Primary outcome
Hear rate variability
Time frame: Pre-match 24 hours before (baseline); Post-match 24 hours (pre-intervention); Immediately post-intervention; 15 minutes post-intervention; 30 minutes post-intervention
HRV will be assessed using a heart rate monitor (Polar H10; Polar Electro Oy, Kempele, Finland) with participants in the supine position in a quiet room (~25 °C, dim lighting). Cardiac signals will be recorded for 3 minutes via a chest strap. Participants will avoid caffeine, alcohol, tobacco, and intense exercise for 12 h prior, and refrain from speaking or voluntary movements during recording. Analysis will be performed with Kubios HRV 3.1.0 (University of Kuopio, Finland), examining LF/HF ratio, LF (0.04-0.15 Hz) and HF (0.15-0.40 Hz) power in normalized units, SDNN, and RMSSD.
1 secondary outcome
Maximal Inspiratory Pressure
Time frame: Pre-match 24 hours before (baseline); Post-match 24 hours (pre-intervention); Immediately post-intervention; 15 minutes post-intervention; 30 minutes post-intervention
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 28 Jan 2026.
- Individual participant dataSharing planned: Yes. The availability of the data, and the materials will be available at the request of the publisher.
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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.
Questions about this trial
What is this clinical trial studying?
A study testing Inspiratory muscle activation via phrenic nerve modulation and Inspiratory muscle activation via threshold device in people with Sports Physical Therapy and Injury;Sports, run by Sierra Varona SL.
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 5 inclusion and 7 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 28 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
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 Arturo Ladriñan, PhD (925 26 88 00, arturo.ladrinan@uclm.es), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Hear rate variability (time frame: Pre-match 24 hours before (baseline); Post-match 24 hours (pre-intervention); Immediately post-intervention; 15 minutes post-intervention; 30 minutes post-intervention). 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 28 Jan 2026.