Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04950387 |
| Other study ID # |
LzdKtvsPfJu2014 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
July 1, 2020 |
| Est. completion date |
March 15, 2021 |
Study information
| Verified date |
June 2021 |
| Source |
University of South Bohemia |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Forty-six endurance runners, 23 males (age = 16.4±1.1) and 23 females (age=16.8±1.1)
participated in our study. The contribution of abdominal, thoracic, and subclavian
musculature to respiration and ventilation parameters during three different intensities on a
cycle ergometer was assessed pre- and post-intervention.
Description:
Subjects Forty six distance runners (14-18 years) participated in our study, 23 males (age =
16.4±1.1, height = 177.1±5.8 cm, weight = 62.4±5.8 kg) and 23 females (age = 16.8±1.1, height
= 168.5±4.4 cm, weight = 55.9±4.0 kg). All participants reported a history of endur-ance
running of at least six times a week for the past year. Participants were randomly al-located
to an experimental group (n=23), which took part in an eight-week breathing in-tervention, or
a control group (n=23), which continued training but did not carry out any breathing
exercises. One participant did not complete the intervention for medical rea-sons, so was
excluded from the study. The two groups, both experimental and control, followed the same
training program, the only difference being that the experimental group performed breathing
exercises. A randomization sequence has been generated using Randomization.org. An
independent person not involved in this study made the comput-er-generated randomization
sequence. The study protocol was reviewed and approved by the local Ethics Committee on
October 19, 2018 (002/2018) and followed the guidelines of the World Medical Assembly
Declaration of Helsinki. Written informed consent to partic-ipate was provided by guardians
and verbal assessment was provided by the partici-pants.
Study design We evaluated ventilatory musculature involvement in three basic areas using a
muscle dynamometer MD03 as previously described. The device is a four-channel digital muscle
dynamometer that, by design, al-lows instantaneous values of muscle force to be measured in
relation to time (i.e., both the force size and its dynamics can be evaluated). In general,
different muscles and muscle groups on the human body can be measured. MD03 is made up of
four muscle probes (we used three probes) that attach themselves to the human body with
belts. The probes contain a strain transducer to a digital signal that is transmitted to a
microprocessor evalua-tion unit that adjusts digital signals from the probes into a
compatible form with a USB input to a notebook. Two software levels (SW1 and SW2) are part of
MD03. Probe attachment sites were selected based on the kinematics of the aforementioned
thoracic sectors. The first probe was placed in the lower respiratory sector on the ventral
side of the level L4-5. In the middle wind sector at the level of 8.-9. ribs, on the ventral
side below the sternum, a second probe was placed. A third level probe was placed in the
upper respiratory sector 3.-4. ribs on the ventral side in the sternal area. Chest
compression and expansion during respiration change the force applied to the individual
sensors in the attached belt.
Inspiratory and expiratory forces exerted on individual probes located in the given breathing
sectors were recorded for 60-sec and minute averages were determined for each probe. After
60-sec of resting data acquisition using spontaneous breathing and deep breathing,
participants underwent an incremental test on a cycle ergometer (Lode, Gro-ningen, The
Netherlands) and oxygen consumption, tidal volume, respiratory rate and minute ventilatory
volume were continuously monitored (Metalyzer B3, Cortex, Leipzig, Germany). The testing
protocol was made relative to participant body weight (i.e., W·kg-1) and began with a 4-min
stage at 1 W·kg-1 followed by three, two-minute stages at progres-sive intensities (2, 3, 4
W·kg-1) and cadence was standardized to 95-100 rev·min-1. Ventilatory muscular involvement of
the abdominal, thoracic, and subclavian body sectors was monitored during the last minute of
each of the three submaximal intensities.
The training program lasted eight weeks. The experimental group performed breath-ing
exercises daily. In the first week of the breathing intervention, training of breathing
ex-ercises took place in the form of three supervised as group breathing sessions. In the
following weeks, there were always two group training sessions, each last ~30 minutes. They
practiced right on the schedule. On unsupervised days, participants were asked to perform
exercises individually at home for at least 10 minutes. Information about the length of each
individuals training session was recorded in a diary by the participant.
The set of breathing exercises was based on yoga, the aim was to activate the dia-phragm and
become aware of individual breathing sectors. As such, breath training in-cluded a variety of
exercises such as breathing wave training, full breathing (breathing in-to all sectors) and
paced breathing (breathing in a specified rhythm). The exercises were performed in various
positions, including lying down, sitting in the kneeling position, sit-ting, kneeling, and
standing. All breathing was performed through the nose. At the begin-ning of the
intervention, the participants breathed spontaneously, later switching to pro-longing the
inspiratory and expiratory phases. They started with a 1: 1 ratio of inhale to exhale length.
Gradually, the pre-exhalation and pre-exhalation phases of breath holding were included:
inspiration - 6 periods, holding breath - 3 periods, exhaling - 6 periods, holding breath - 3
periods. Each of the participants adapted the exercise to their individual respiratory rate.
Each of the exercises was repeated 6 times. The exercises were slow, with a deep focus on
breathing, in line with the movement. Very important was the perception of the direction of
movement and expansion of the chest, the behavior of the axis of the body (head, spine,
pelvis), which they learned during the introductory meetings. The control group did not
participate in any form of breathing training and were told to go about their lives as usual.
The follow-up testing, which was the same as the aforementioned described graded maximal test
on the cycle ergometer, was performed after 8 weeks of intervention. The control group was
always tested at the same time as the members of the intervention group.
