The Effect Of Respiratory Muscle Training On The Pulmonary Function, Lung Ventilation, And Endurance Performance Of Young Soccer Players
Authors: Krzysztof Mackała, Monika Kurzaj, Paulina Okrzymowska, Jacek Stodółka, Milan Coh, Krystyna Rożek-Piechura
DOI / Source: 10.3390/ijerph17010234
Date: 28 December 2019
Reading level: Intermediate
Why This Matters for Freedivers
Freedivers love IMT, but the big question is always: does it actually improve performance, or does it just make you better at breathing against a device? This study suggests IMT can meaningfully boost breathing muscle strength and may improve endurance performance even when basic lung-function numbers don’t change much—useful for setting expectations and choosing where IMT fits in your training.
Synopsis
This study looked at a practical, real-world question: if young athletes add inspiratory muscle training (IMT) to their normal training, does it change lung function, breathing muscle strength, and endurance performance?
Sixteen junior club-level soccer players were split into two groups. Both groups did the same 8-week preseason program, including incremental endurance training (running sessions that gradually get harder). The IMT group also did breathing muscle training using a common pressure-threshold device (Threshold IMT). Their protocol was structured and progressive: two sessions per day, five days per week, for eight weeks, totalling 80 sessions. The training load started at a moderate fraction of each athlete’s maximal inspiratory pressure and increased over the weeks, aiming for progressive overload rather than “just doing some breathing.”
The researchers tested three main things before and after:
1) Pulmonary function (spirometry) — values like vital capacity and forced expiratory measures.
2) Respiratory muscle strength — maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax).
3) Endurance performance — a 12-minute Cooper run test, used to estimate VO2max from distance covered.
What happened is a pattern you’ll see a lot in athletic breathing studies: the IMT group got much stronger breathing muscles, but their basic spirometry numbers didn’t change much. The IMT group showed large improvements in inspiratory strength (PImax) and also improved expiratory strength (PEmax). However, classic “lung function” values (the ones people often assume will rise) barely moved—likely because these were already healthy, trained teenagers who started near normal/upper ranges, so there wasn’t much room to improve those measures.
The more interesting outcome was performance: both groups improved their Cooper test distance (which is expected during preseason running training), but the IMT group improved more, leading to a bigger estimated increase in VO2max. In plain terms: adding IMT didn’t make their lungs “bigger” on a spirometry printout, but it may have made breathing less limiting during hard effort, helping them hold pace better over a sustained run.
For freedivers, the lesson is practical: if you use IMT, don’t judge success by spirometry alone. A stronger breathing pump may help performance and “breathing cost” under stress even if your standard lung function tests hardly change.
Abstract
This study investigated whether the addition of eight weeks of inspiratory muscle training (IMT) to a regular preseason soccer training program, including incremental endurance training (IET), would change pulmonary function, lung ventilation, and aerobic performance in young soccer players. Sixteen club-level competitive junior soccer players participated in the study. Participants were randomly assigned into two groups: experimental and control. Both groups performed regular preseason soccer training, including endurance workouts as IET. In addition to this training, the experimental group performed additional IMT for eight weeks with a commercially available respiratory muscle trainer (Threshold IMT), with a total of 80 inhalations (twice per day, five days per week). Pre- and post-intervention tests of pulmonary function, maximal inspiratory pressure, and the Cooper test were implemented. Eight weeks of IMT had a positive impact on expiratory muscle strength; however, there was no significant effect on respiratory function parameters. The results also indicate increased efficiency of the inspiratory muscles, contributing to an improvement in aerobic endurance, measured by VO2max estimated from running distance in the cardiorespiratory Cooper test.