Effects of Inspiratory Muscle Training on Lung Function Parameter in Swimmers, A Systematic Review and Meta-Analysis
Authors: Nathali Carvajal-Tello, José Guillermo Ortega, Andrés Fabricio Caballero-Lozada, María Juliana Devia-Quiñonez, Isabella González-Calzada, Daniela Rojas-Hernández, Alejandro Segura-Ordoñez
DOI / Source: 10.3389/fspor.2024.1429902
Date: 16 September 2024
Reading level: Intermediate
Why This Matters for Freedivers
A lot of freedivers use inspiratory muscle training (IMT) hoping it will “grow the lungs,” improve gas exchange, or directly increase apnea performance. This review is useful because it separates what IMT clearly does (increase inspiratory muscle strength) from what it usually doesn’t do (change standard spirometry measures like FEV1 and FVC). If you’re using IMT for freediving, this supports a more realistic goal: stronger breathing muscles may help comfort and control around ventilation (warm-ups, recovery breathing, repeated efforts, surface work), but you shouldn’t assume it will measurably increase lung volumes or automatically translate into big apnea gains.
Synopsis
This paper reviews whether inspiratory muscle training (IMT) changes lung function in swimmers, and it combines results using meta-analysis. The authors focused on controlled clinical trials and prospective longitudinal studies where swimmers used standardized IMT devices (most commonly PowerBreathe), published between 2012 and 2023.
Across 13 studies (277 participants aged roughly 11–21; mostly elite swimmers), IMT programs were typically short and practical: 3–12 weeks, 1–2 sessions per day, 3–6 days per week, often around 30 breaths per session. Many protocols started around ~50% of maximal inspiratory pressure (MIP) and progressed toward higher loads (often up to ~80%).
The key finding is consistent: IMT improves inspiratory muscle strength. Pooled results showed a clear increase in MIP after IMT. In contrast, standard lung function measures such as FEV1 and FVC generally did not show meaningful change when results were combined. Some individual studies reported small improvements, but overall effects on spirometry were not reliable and the results varied a lot between studies (high heterogeneity).
A practical interpretation is that IMT mainly trains the “pump” (respiratory muscles) rather than changing the structure or mechanical properties of the lungs and airways that spirometry reflects. For performance, some studies reported time-trial improvements, but performance outcomes were inconsistent and not the main reliable takeaway of the pooled data.
For freedivers, this supports using IMT as a targeted strength/conditioning tool (for breathing muscle strength and fatigue resistance), while keeping expectations realistic about lung volumes and “lung capacity” changes.
Abstract
This systematic review and meta-analysis aimed to assess the impact of inspiratory muscle training (IMT) on lung function parameters (MIP, MEP, FEV1, and FVC) in both elite and non-elite swimmers. Controlled clinical trials and prospective longitudinal studies published between 2012 and 2023 were identified across multiple databases. Thirteen studies involving 277 participants were included. IMT was most often performed using the PowerBreathe device over 3–12 weeks, typically 1–2 sessions per day, 3–6 times per week, with around 30 repetitions, starting near 50% of MIP and progressing toward higher loads. Meta-analysis showed IMT was associated with higher maximal inspiratory pressure (MIP), while FEV1 and FVC were not meaningfully changed overall. The conclusion was that swimmers using IMT improved inspiratory muscle strength, particularly MIP, without consistent changes in other lung function measures.