Longitudinal Assessment of Maximal Inspiratory Pressure and Functional Capacity Following Inspiratory Muscle Training in Frail Older Adults (IMT-2)

Longitudinal Assessment of Maximal Inspiratory Pressure and Functional Capacity Following Inspiratory Muscle Training in Frail Older Adults: A Randomized, Double-Blind, Sham-Controlled Trial

This study aims to evaluate the effects of an 8-week inspiratory muscle training program on maximal inspiratory pressure and functional capacity in frail older adults aged 80 years and above. Frailty is associated with reduced physical capacity, declines in functional performance, impaired respiratory performance, and a higher risk of disability. Inspiratory muscle training is a simple, low-cost intervention that may improve breathing function, inspiratory muscle strength, and overall health in very old adults, but evidence in this age group remains limited.

Participants will be randomly assigned to one of two groups: a high-load inspiratory muscle training group or a low-load sham training group. Both groups will use a threshold device and perform 30 breaths once per day, five days per week, for eight weeks. The experimental group will train with progressively increasing resistance (50% to 80% of maximal inspiratory pressure), while the sham group will use a minimal and non-progressive load (15% of maximal inspiratory pressure). All sessions will be supervised and monitored for safety.

The main goal of the study is to determine whether inspiratory muscle training improves maximal inspiratory pressure (MIP), an established measure of global inspiratory muscle strength. Secondary outcomes include measures of functional capacity, reflecting the ability to perform physical tasks relevant to daily living in very old adults. These outcomes will allow the evaluation of the clinical relevance of improvements in inspiratory muscle strength in this population.

Assessments will be performed before the intervention, immediately after the 8-week program, and again at one and three months after the end of the intervention to examine both immediate and short-term effects. This study may contribute valuable evidence regarding the safety, feasibility, and clinical benefits of inspiratory muscle training in frail very old adults, particularly its impact on inspiratory muscle strength and functional capacity, supporting its potential implementation in rehabilitation and geriatric care.

Study Overview

• Status: Not yet recruiting
• Conditions: Frailty Syndrome; Respiratory Muscle Weakness; Age-Related Frailty; Geriatric Health
• Intervention / Treatment: Device: Sham Inspiratory Muscle Training; Device: Inspiratory Muscle Training

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Sandra Sánchez Jorge, PhD; Phone Number: +34 913 24 80 64; Email: s.sjorge.prof@ufv.es

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults aged 80 years or older.
• Clinical diagnosis of frailty, defined by a Short Physical Performance Battery (SPPB) score < 9.
• Ability to stand and walk with or without assistive devices.
• Ability to understand and follow instructions for inspiratory muscle training.
• Stable medical condition for at least 3 months prior to enrollment.
• Capacity to provide informed consent or availability of a legal

Exclusion Criteria:

• Acute or unstable cardiovascular, respiratory, or metabolic conditions.
• Severe cognitive impairment that prevents understanding the procedures.
• Diagnosis of neuromuscular diseases affecting respiratory muscles (e.g., ALS, myopathies).
• Severe or uncontrolled hypertension (≥180/110 mmHg).
• Recent thoracic or abdominal surgery (<3 months).
• Severe musculoskeletal disorders limiting participation in training.
• History of recurrent syncope, severe dizziness, or intolerance to respiratory maneuvers.
• Any condition judged by the research team to compromise safety or participation.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Inspiratory Muscle Training; Participants perform an 8-week inspiratory muscle training program using a threshold device (PowerBreathe). Training consists of 30 inspirations, once daily, 5 days per week. The initial load is set at 50% of each participant's maximal inspiratory pressure (MIP) and is increased weekly by 5 cmH#O up to 80% of MIP. All sessions are supervised by healthcare professionals, with continuous monitoring of oxygen saturation and heart rate	Device: Inspiratory Muscle Training; Participants perform 30 breaths once daily, 5 days per week for 8 weeks using a threshold inspiratory muscle training device. The load begins at 50% of maximal inspiratory pressure (MIP) and increases by 5 cmH#O weekly up to 80% of MIP. Sessions are supervised and oxygen saturation and heart rate are monitored.
Sham Comparator: Inspiratory Muscle Training (Sham); Participants follow the same 8-week training schedule using the threshold device (PowerBreathe), but with a constant load of 15% of maximal inspiratory pressure (MIP) and no weekly progression. Training consists of 30 inspirations, once daily, 5 days per week. The procedure mimics the experimental intervention but provides minimal physiological stimulus. All sessions are supervised, with monitoring of oxygen saturation and heart rate	Device: Sham Inspiratory Muscle Training; Participants use the same device and schedule as the experimental group (30 breaths once daily, 5 days per week for 8 weeks) but with a constant load of 15% of maximal inspiratory pressure (MIP), with no weekly progression. This mimics the procedure while providing minimal physiological stimulus. Supervision and monitoring are identical to the experimental arm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal Inspiratory Pressure (MIP)	Maximal Inspiratory Pressure (MIP) will be measured using a calibrated handheld manometer following standardized respiratory assessment guidelines. Participants will be instructed to perform a maximal inspiratory effort from residual volume through the mouthpiece with their nose occluded. At least three maneuvers will be recorded, ensuring less than 10% variability between attempts. The highest reproducible value (cmH₂O) will be used for analysis. This measure reflects global inspiratory muscle strength and is widely validated in older and frail populations.	Before-intervention; Immediately after intervention; 1-month after intervention; 3 months after intervention
Six-Minute Walk Test (6MWT)	Functional exercise capacity will be assessed using the Six-Minute Walk Test (6MWT). Participants will be instructed to walk at their fastest possible pace for six minutes along a 30-meter corridor, covering the greatest distance possible. The total distance walked (in meters) will be recorded. Participants will be continuously accompanied by the therapist and may use assistive devices and/or supplemental oxygen if required.	Before-intervention; Immediately after intervention; 1-month after intervention; 3 months after intervention
Timed Up and Go Test (TUG)	Functional mobility and fall risk will be evaluated using the Timed Up and Go (TUG) test. Participants will start seated in a chair with armrests. On command, they will stand up, walk 3 meters, turn around, return to the chair, and sit down. The total time to complete the task will be recorded in seconds. Interpretation criteria: < 20 seconds: normal performance ≥ 20 seconds: increased risk of falls	Before-intervention; Immediately after intervention; 1-month after intervention; 3 months after intervention
Five Times Sit-to-Stand Test (5STS)	Lower limb functional strength will be assessed using the Five Times Sit-to-Stand Test (5STS). Participants will sit on a 43-45 cm high chair without armrests, with arms crossed over the chest, and will be instructed to stand up and sit down five times as quickly as possible. The total time to complete the test will be recorded in seconds. The minimal detectable change ranges from 3.6 to 4.2 seconds, and the minimal clinically important difference is 2.3 seconds. Age-related normative values will be considered for interpretation.	Before-intervention; Immediately after intervention; 1-month after intervention; 3 months after intervention
Upper Limb Muscle Strength (Handgrip Dynamometry)	Upper limb muscle strength will be assessed using handgrip dynamometry following the recommendations of the American Society of Hand Therapists. Participants will be seated with the shoulder in adduction and neutral rotation, the elbow flexed at 90°, the forearm in neutral position, and the wrist positioned between 0° and 30° of extension. Three maximal grip strength measurements will be obtained from the dominant hand, with 1 minute of rest between trials. The highest value will be selected for analysis. Handgrip strength will be measured using a JAMAR dynamometer (Lafayette Instrument, Lafayette, IN, USA).	Before-intervention; Immediately after intervention; 1-month after intervention; 3 months after intervention
Lower Limb Muscle Strength (Isometric Knee Extension Dynamometry)	Lower limb muscle strength will be assessed using isometric dynamometry to evaluate maximal voluntary contraction (MVC) of the knee extensors. The protocol described by Hung et al. will be followed. Participants will perform two maximal isometric contractions, each lasting 5 seconds, with 3 minutes of rest between contractions to allow phosphocreatine resynthesis. Participants will be seated at the edge of a physiotherapy table with the knee positioned at 90° of flexion. The dynamometer will be placed at the level of the malleoli to standardize the lever arm and ensure maximal isometric contraction. The peak force achieved during each contraction will be recorded and normalized to body weight, with results expressed in Newtons (N). Lower limb dynamometry will be performed using the ActiveForce 2 device (Activbody, San Diego, CA, USA).	Before-intervention; Immediately after intervention; 1-month after intervention; 3 months after intervention
Muscle Oxygenation	Muscle oxygen saturation (SmO₂) will be assessed using the Moxy Monitor (Fortiori Design LLC, Hutchinson, MN, USA), a wireless and portable device based on near-infrared spectroscopy (NIRS). The measurement protocol described by Contreras-Briceño et al. will be followed and will consist of a 180-second resting measurement, followed by continuous monitoring during the Six-Minute Walk Test (6MWT). Outcome values will correspond to the mean SmO₂ (%) recorded during the final 30 seconds of each phase. The sensor will be placed over the muscle belly of the vastus lateralis following standard NIRS placement recommendations.	Before-intervention; Immediately after intervention; 1-month after intervention; 3 months after intervention
Total Hemoglobin Concentration (THb)	Total hemoglobin concentration (THb) will be assessed using the same NIRS device (Moxy Monitor, Fortiori Design LLC, Hutchinson, MN, USA). Data acquisition and analysis will be performed using dedicated software (Moxy Software v1.5.5; Idiag, Fehraltorf, Switzerland). The same protocol will be applied: a 180-second resting measurement followed by continuous monitoring during the Six-Minute Walk Test (6MWT). Outcome values will correspond to the mean THb values recorded during the final 30 seconds of each phase. The sensor placement will be identical to that used for SmO₂ assessment (vastus lateralis).	Before-intervention; Immediately after intervention; 1-month after intervention; 3 months after intervention

Collaborators and Investigators

• Sponsor: Universidad Francisco de Vitoria

Study record dates

Study Major Dates

• Study Start (Estimated): February 1, 2026
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): September 10, 2026

Study Registration Dates

• First Submitted: December 19, 2025
• First Submitted That Met QC Criteria: January 3, 2026
• First Posted (Actual): January 9, 2026

Study Record Updates

• Last Update Posted (Actual): January 9, 2026
• Last Update Submitted That Met QC Criteria: January 3, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Older Adults; Inspiratory Muscle Training; Diaphragm Ultrasound
• Additional Relevant MeSH Terms: Pathologic Processes; Pathological Conditions, Signs and Symptoms; Frailty
• Other Study ID Numbers: UFV-IMT2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

IPD Plan Description

At this time, it is unclear whether individual participant data (IPD) will be shared.

Data sharing will depend on institutional policies, ethical approvals, participant privacy considerations, and the feasibility of preparing de-identified datasets. A final decision will be made once data collection and analysis are completed.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No