Effects of Inspiratory Muscle Fatigue and Warm-up on Respiratory Variables, Handgrip Strength, and Walking Capacity in Sedentary Older Adults

Effects of Inspiratory Muscle Fatigue and Warm-up on Respiratory Variables, Handgrip Strength, and Walking Capacity in Sedentary Older Adults: A Randomized Clinical Trial.

Respiratory muscle training represents an effective method increasingly utilized in both sports and healthcare domains, employing various devices, among which threshold devices are prominent. The aim of this study is to determine the relationship between inspiratory muscle fatigue or warm-up and muscular strength in upper and lower limbs, in sedentary older adults, as well as the association between such fatigue and other variables, including maximal inspiratory pressure, diaphragmatic ultrasonography, functionality and handgrip strength.

According to our hypothesis, the execution of a protocol inducing inspiratory muscle fatigue or activation in sedentary older adults could influence muscular strength, respiratory function and exercise capacity.

In this study, subjects will be divided into three groups: the fatigue group , the activation group and the control group.

Measurements of variables, such as maximal inspiratory pressure, diaphragmatic strength (ultrasound image) and functional capacity, will be conducted.

This is a randomized control trial. The fatigue group (EG) will perform the inspiratory muscle fatigue protocol using a specific inspiratory endurance test, in which volunteers, one-on-one, and in a single session, will breathe against submaximal inspiratory loads equivalent to 60% of their Maximum Inspiratory Pressure (MIP) through a threshold valve device. The participants will follow a free pattern of breathing until they are unable to establish flow during at least 3 maximum inspiratory efforts.

The activation group (AG) will perform the protocol of 2 sets of 30 repetitions at 15% of their MIP, one-on-one, and in a single session, using a threshold valve device.

The control group will do a seat and wait.

The interventions will be supervised by a physiotherapist. The primary outcomes will be

Walking capacity will be assessed using the 6 minutes walking test (6MWT) immediately before intervention and immediately after intervention Respiratory muscle strength will be assessed using a respiratory pressure meter or manometer designed, and with ultrasound image measuring the cross sectional area of the diaphragm at 8-9th rib level and speed of contraction with a deep and fast inspiratory manoeuver. This will be done immediately before intervention and immediately after intervention Handgrip strength will be assessed using a handgrip dynamometer. This will be done immediately before intervention and immediately after intervention.

Inclusion Criteria:

• Being over 60 years old.
• Physical independence in terms of gait and transfers
• Engaging in less than 150 minutes of physical activity per week.

Exclusion Criteria:

• Having any pathology that prevents the performance of physical activity.
• Subjects with impaired cognitive abilities.
• Subjects with tympanic perforation or middle-inner ear pathology.
• Subjects with chronic respiratory, cardiac, renal, or metabolic pathology..
• Subjects who have undergone lower limb surgery within the past 12 months.