Effects of hypoventilation sprint training on physical performance in professional ice hockey players
| ISRCTN | ISRCTN13253795 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN13253795 |
| Sponsor | Comenius University Bratislava |
| Funder | Agentúra na Podporu Výskumu a Vývoja |
- Submission date
- 13/08/2026
- Registration date
- 04/09/2026
- Last edited
- 04/09/2026
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Other
Plain English summary of protocol
Background and study aims
Ice hockey players often perform many short, very intense skating sprints during a match and need to recover quickly between efforts. Training methods that target repeated‑sprint ability may therefore help players to improve sport‑specific fitness. Voluntary hypoventilation at low lung volume (holding the breath after exhalation during exercise) can temporarily reduce oxygen levels and increase carbon dioxide in the body, which may stimulate different physiological adaptations compared with normal breathing. This study aimed to compare the effects of a 5‑week on‑ice repeated‑sprint training programme performed with voluntary hypoventilation at low lung volume versus the same training with normal breathing on hockey‑specific performance and selected physiological responses in professional ice hockey players.
Who can participate?
Male professional ice hockey players from the second‑highest professional league in Slovakia were invited to take part. Participants had to be in good general health, without chronic respiratory disease or hypertension, and had to be able to attend at least 80% of the regular team training sessions and the experimental training sessions during the study period. Players who developed illnesses requiring antibiotics or who sustained injuries that significantly interrupted training during the study period were not able to complete the full protocol.
What does the study involve?
The study was carried out during the preseason period. All participating players followed the same team training programme, consisting of about five sessions per week (approximately 11 hours of training: 4 hours on‑ice and 7 hours off‑ice). In addition, players completed ten supervised repeated‑sprint training sessions on ice over 5 weeks. In these sessions, they performed short maximal skating sprints over distances of 36–44 metres with passive recovery between sprints. Experimental group performed sprints with breath-holding after exhalation. Control group did the same training with normal breathing. The sprint distance, number of sprints and recovery time were progressively adjusted over the 5 weeks.
Before and after the 5‑week intervention, all participants completed a series of tests: an on‑ice repeated‑sprint ability test, a Yo‑Yo Intermittent Recovery Test Level 2, a short high‑intensity cycling test, a maximal incremental cycling test to assess cardiorespiratory fitness, static and walking breath‑holding tests, and resting blood sampling for haematological measurements. All tests were carried out under standardized conditions, and participants received detailed instructions before each test.
What are the possible benefits and risks of participating?
By taking part, players could benefit from additional, structured on‑ice conditioning aimed at improving repeated‑sprint performance and intermittent endurance. The study was also designed to help coaches and sports scientists to better understand how breath‑holding strategies during sprint training influence performance and physiological responses in ice hockey. However, direct performance benefits for each individual player could not be guaranteed.
The risks were similar to those associated with demanding high‑intensity training, such as temporary fatigue, muscle soreness, and discomfort during maximal exercise tests. Breath‑holding during sprints could cause short‑lasting feelings of breathlessness or dizziness in some players, but the protocol was carefully supervised, and players could stop at any time if they felt unwell. All procedures were reviewed and approved by the institutional ethics committee, and safety precautions were followed throughout the study.
Where is the study run from?
The study was coordinated by the Faculty of Physical Education and Sports at Comenius University in Bratislava, Slovakia. On‑ice training sessions and the repeated‑sprint test were performed on an indoor ice rink in Hamuliakovo, Slovakia. Laboratory‑based tests (cycling, breath‑holding and blood sampling) were conducted at the Faculty of Physical Education and Sports in Bratislava under standardized environmental conditions.
When is the study starting and how long is it expected to run for?
The study was carried out during one preseason period. For this protocol, all training sessions and measurements took place between May and June 2025. The experimental training programme lasted for 5 weeks, during which players completed ten on‑ice repeated‑sprint sessions in addition to their regular team training. Pre‑intervention tests were completed within the week before the intervention started, and post‑intervention tests were completed within the week after the intervention ended.
Who is funding the study?
The study was funded by research grants from the Ministry of Education, Research, Development and Youth of the Slovak Republic (APVV‑22‑0047, APVV booster 09I03‑03‑V06‑00062, and APVV‑23‑0028). These public research funds supported the design, data collection and analysis, but did not influence how the study was conducted or reported.
Who is the main contact?
The main contact for this study is a dean of the Faculty of Physical Education and Sports, Comenius University in Bratislava - prof. Viktor Bielik and his PhD student - Frantisek Lorinczi. Contact details (Viktor Bielik, viktor.bielik@uniba.sk; Frantisek Lorinczi, frantisek.lorinczi@uniba.sk)
Contact information
Scientific
Nábr. arm. gen. L. Svobodu 9
Bratislava
814 69
Slovakia
 ORCID ID |
0000-0001-9525-4983 |
|---|---|
| Phone | +421 948043444 |
| viktor.bielik@uniba.sk |
Public, Principal investigator
Nábrežie arm. gen. L. Svobodu 9
Bratislava
814 69
Slovakia
| ORCID ID |
0000-0001-8182-2038 |
|---|---|
| Phone | +421 907591551 |
| frantisek.lorinczi@uniba.sk |
Study information
| Primary study design | Interventional |
|---|---|
| Allocation | Randomized controlled trial |
| Masking | Open (masking not used) |
| Control | Active |
| Assignment | Parallel |
| Purpose | Physical condition & sport performance enhancement |
| Scientific title | Effects of a 5-week on-ice repeated-sprint training with voluntary hypoventilation at low lung volume in professional ice hockey players: a randomised controlled trial |
| Study objectives | 1. To determine whether a 5‑week on‑ice repeated‑sprint training programme combined with voluntary hypoventilation at low lung volume (RSH‑VHL) led to greater improvements in sport‑specific and non‑specific conditioning abilities than matched repeated‑sprint training with unrestricted breathing (RSN) in professional ice hockey players 2. To compare the effects of RSH‑VHL and RSN on selected physiological responses at rest and during exercise, including cardiorespiratory variables, lactate kinetics and haematological parameters 3. To explore which performance and physiological variables were associated with changes in on‑ice repeated‑sprint ability following the intervention, using regression analyses |
| Ethics approval(s) |
Approved 12/12/2022, Etická komisia Fakulty telesnej výchovy a športu (Nábrežie arm. gen. L. Svobodu 9, Bratislava, 814 69, Slovakia; +421 940522111; eticka.komisiafsport@uniba.sk), ref: 6/2022 |
| Health condition(s) or problem(s) studied | Physical abilities - aerobic endurance, anaerobic endurance, repeated sprint ability Breath-holding ability, Lactate clearance, Hematopoiesis |
| Intervention | Intervention group – repeated‑sprint training with voluntary hypoventilation at low lung volume (RSH‑VHL) Participants continue their usual team training (about five sessions per week, approximately 11 hours of training: 4 hours on‑ice and 7 hours off‑ice) and, in addition, complete ten supervised on‑ice repeated‑sprint training sessions over 5 weeks. Each training session consists of all‑out ice‑skating sprints over distances of 36–44 metres, performed in sets with passive recovery between sprints. Across the 5‑week period, sprint distance and the number of repetitions are progressively increased, while the time between sprint departures is progressively reduced, with a constant number of sets. All sprints are performed while holding a hockey stick. In the intervention group, participants perform the repeated‑sprint training with voluntary hypoventilation at low lung volume. Before each sprint, they exhale to approximately functional residual capacity and then skate at maximal velocity while holding their breath until the end of the sprint. During the recovery periods between sprints, they breathe normally. Participants receive two familiarisation sessions with the hypoventilation technique (one off‑ice running and one on‑ice) before starting the intervention. Control group – repeated‑sprint training with unrestricted breathing (RSN) Participants in the control group follow the same overall team training programme and complete the same ten on‑ice repeated‑sprint training sessions over 5 weeks, with identical sprint distances, number of repetitions, recovery intervals and progression of training load. All sprints are performed while holding a hockey stick. In the control group, participants perform the repeated‑sprint training with unrestricted breathing. They are instructed to breathe normally throughout each sprint and during the recovery periods between sprints. Allocation to groups Participants are randomly allocated in a 1:1 ratio to the intervention group (RSH‑VHL) or the control group (RSN) using a parallel‑group design. All training sessions take place on the same indoor ice rink under stable environmental conditions, and the intervention is delivered by qualified coaches and researchers. |
| Intervention type | Behavioural |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) |
|
| Completion date | 30/06/2025 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 35 Years |
| Sex | Male |
| Target sample size at registration | 23 |
| Total final enrolment | 25 |
| Key inclusion criteria | 1. Adulthood (18+ years) 2. Absence of chronic respiratory disease or hypertension 3. Competing level in ice-hockey |
| Key exclusion criteria | Illness requiring antibiotic treatment or injury |
| Date of first enrolment | 19/05/2025 |
| Date of final enrolment | 19/05/2025 |
Locations
Countries of recruitment
- Slovakia
Study participating centres
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|
Editorial Notes
13/08/2026: Trial's existence confirmed by the Ethics Committee of the Faculty of Physical Education and Sports, Comenius University in Bratislava.
