Injury;Sports, Sports Physical Therapy
Conditions
Brief 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. 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.
Interventions
DEVICEInspiratory muscle activation via phrenic nerve modulation
Phrenic nerve stimulation using low-frequency symmetric biphasic current
DEVICEInspiratory muscle activation via threshold device
Deep inspirations against submaximal inspiratory load
Sponsors
Sierra Varona SL
University of Alcala
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* 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.
Exclusion criteria
* 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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Hear rate variability | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Maximal Inspiratory Pressure | Pre-match 24 hours before (baseline); Post-match 24 hours (pre-intervention); Immediately post-intervention; 15 minutes post-intervention; 30 minutes post-intervention | 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. |
Contacts
CONTACTArturo Ladriñan, PhD
Outcome results
None listed