An interventional study of Repeated sprint in Normobaric Hypoxia, Hypoventilation and Normoxia, sponsored by Faculdade de Motricidade Humana. Completed at 1 site in Portugal. Open to participants aged 18 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-09.
Sponsored by Faculdade de Motricidade Humana · Not applicable, Interventional, and Other
To overcome the lack of knowledge regarding the impact of different "living low, training high" methods on swimming performance, a 4-week intervention will be carried out to determine and compare the effects of three Repeated Sprints in Hypoxia (RSH) methods with each other and with a control group. Our goal is to characterize and compare the adaptations in swimming performance and in cardiorespiratory, metabolic, and muscle oxygenation responses that can arise after a 4-week training period of RSH and RSN performed in a ski-ergometer.
Recently, several new "living low training high" (LLTH) methods involving repeated sprints in hypoxia have shown promising results, especially in team sports. However, the underlying mechanisms remain mostly unclear, as does its effectiveness in improving swimming performance.
Hypoxemia can be induced by exposure to ambient hypoxia conditions, by voluntary hypoventilation at low lung volume, or by vascular occlusion (namely, blood flow restriction). Swimming performance is influenced by aerobic and anaerobic metabolism and could benefit from these different LLTH methods.
This project aims to compare the effects of repeated sprint training performed with a ski-ergometer 1) in a hypoxic chamber; 2) in normoxia 3) in control group on the performance of swimmers, as well as to characterize cardiorespiratory, metabolic, and muscle oxygenation adaptations that may contribute to the improvements achieved after four weeks of each of these types of training.
All groups will be evaluated before and after the supervised training period in three testing sessions in normoxia, separated by at least 24 hours within 7 days. Swimmers will perform: 1) time-trial (100 m front crawl) in the swimming pool to determine performance, V̇̇O2 peak, and lactate concentration following the test; 2) incremental test to exhaustion in the swim-ergometer to determine aerobic peak power, cardiorespiratory responses (V̇̇O2max, ventilatory thresholds), and maximal tissue deoxygenation; 3) time-trial test in the ski-ergometer (100 m) to access performance, muscle and pulmonary oxygen uptake kinetics, and the relative contribution of energetic systems.
Training sessions will be performed in the ski-ergometer and consist of 3 sets of 5x10s all-out sprints with 20s and 5 min of passive rest between the sprints and sets, respectively. In all testing and training sessions, pulse oxygen saturation will be measured for safety purposes.
96 studies on the registry are indexed under Hypoventilation; 21 are open to participants now.
This study's enrollment of 32 is below the median of 52 across 63 interventional studies indexed under Hypoventilation.
Browse Hypoventilation studies →Faculdade de Motricidade Humana is the lead sponsor of 21 studies on the registry; 8 are open to participants now.
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Exclusion Criteria:
The RSH group will perform training sessions in a normobaric hypoxic chamber at a simulated altitude of 3000 meters (FiO2 14.5%)
Other: Repeated sprint
Participants did not receive any additional intervention and continued their usual swimming training throughout the study period.
The control group will perform the training sessions in normoxia (FIO2, 20.9%)
Other: Repeated sprint
* The group will endure four weeks (8 sessions) of the assigned training program in addition to the regular swimming training. * Data collection sessions: All groups will be evaluated before and after the supervised training period in three testing sessions in normoxia separated by at least 24 hours within 7 days. * Training sessions: will be performed in the ski ergometer and consist of 3 sets of 5x10s all-out sprints with 20s and 5 min of passive rest between the sprints and sets, respectively.
Ventilatory thresholds and maximum oxygen consumption
mL/kg·min
Time frame: Before and after 4 weeks of supervised training period
Lactate concentration
mmol.L-1
Time frame: Before and after 4 weeks of supervised training period
Muscle oximetry
Near-infrared spectroscopy (NIRS)
Time frame: Before and after 4 weeks of supervised training period
Time-trial
seconds
Time frame: Before and after 4 weeks of supervised training period
Heart rate
bpm
Time frame: Before and after 4 weeks of supervised training period
Arterial oxygen saturation
Oxymetry (%)
Time frame: Before and after 4 weeks of supervised training period
Plan to share: No
No publications or documents are linked to this record.
Ran from Feb 2024 to primary completion in Apr 2025, 14 months.
Of 35 non-industry interventional studies with no phase under Hypoventilation, half reached primary completion within 15 months of starting (the median), counting those still running; a quarter within 5 and three quarters within 26. This study's 14 months is close to that.
Counting every sponsor, half of 35 studies reached it within 15 months; a quarter within 5 and three quarters within 26.
Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 9, 2026: primary completion Apr 2024 → Apr 2025 and completion Jun 2024 → Mar 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is completed, as verified in Feb 2024. You cannot join it, but the record below documents what was studied.
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Faculdade de Motricidade Humana