Normobaric Hypoxia as a Strength Training Intensity Amplifier in Ice Hockey Players: Effects on Anaerobic Performance and Muscle Contraction Properties

NCT06930027 | Enrolling By Invitation

• 1 other identifier: 02/2024
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this research study is to investigate the effects of resistance training performed under normobaric hypoxia (simulated altitude conditions) on anaerobic performance, lactate clearance, and muscle contractility in elite ice hockey players. The main questions it aims to answer are: Does resistance training under hypoxic conditions improve anaerobic peak power and mean power compared to training under normal oxygen conditions? Does training under hypoxia affect lactate kinetics and buffering capacity differently than normoxic training? Does hypoxic training enhance muscle contractility properties differently compared to normoxic training? In practice: Can hypoxic training help injured athletes maintain performance levels while reducing overall physical stress and preventing detraining? Researchers will compare four training approaches: High-intensity training in normoxia (normal oxygen conditions) Low-intensity training in normoxia High-intensity training in hypoxia (simulated altitude of 3500 meters) Low-intensity training in hypoxia Participants will: Perform resistance training sessions using a leg press twice a week for 6 weeks, with progressively increased intensity. Complete anaerobic performance tests (Wingate tests for both lower and upper limbs) before and after the training intervention. Undergo tensiomyographic assessments to evaluate muscle contractility. Provide capillary blood samples at 0, 4, and 8 minutes post-exercise to assess lactate clearance and metabolic recovery.

Conditions

High-intensity Strenght Training in Normoxia (H-N); Low-intensity Strenght Training in Normoxia (L-N); High-intensity Strenght Training in Normobaric Hypoxia (H-H); Low-intensity Strenght Training in Normobaric Hypoxia (L-H)

Keywords

resistance training; anaerobic performance; lactate clearance; muscle contractility; ice hockey; detraining prevention; injury rehabilitation

Outcome Measures

Primary Outcomes (3)

• Anaerobic Performance (2x Wingate Test)

  Change in anaerobic performance will be assessed using peak power (W) and mean power output (W), determined through the Wingate Anaerobic Test performed on a cycle ergometer. Lower-limb anaerobic performance will be evaluated by two consecutive Wingate tests, separated by a 20-minute rest period, to ensure reliability. An additional Wingate test for the upper limbs serves as an internal control.

  Baseline (pre-intervention) and 6 weeks (immediately post-intervention)

• Lactate Clearance Kinetics

  Capillary blood lactate concentrations will be assessed at baseline (0 min immediately post-exercise), and at 4 and 8 minutes post-exercise, to evaluate lactate production and clearance kinetics following maximal anaerobic efforts.

  Baseline (pre-intervention) and 6 weeks (post-intervention)

• Muscle Contractility (Tensiomyography)

  Muscle contractile properties (contraction time-Tc, and maximal radial displacement-Dm) will be assessed via tensiomyography (TMG) on the vastus lateralis muscle (trained muscle group) and triceps brachii (untrained control muscle), to evaluate neuromuscular adaptations following the intervention.

  Time Frame: Baseline (pre-intervention) and 6 weeks (post-intervention)

Secondary Outcomes (1)

• Maximal Strength (1-Repetition Maximum, 1RM)

  Baseline (pre-intervention) and 6 weeks (immediately post-intervention)

Other Outcomes (1)

• Perceived Effort and Fatigue (Rating of Perceived Exertion - RPE)

  Recorded twice weekly, during all training sessions over the 6-week intervention (weeks 1-6).

Study Arms (4)

High-intensity strength training under normoxic conditions (H-N)

ACTIVE COMPARATOR

Participants performed supervised leg press resistance training twice weekly under normal oxygen conditions (normoxia, \~20.9% FiO₂). Each session consisted of four sets of 10 repetitions at 70-80% of their individual one-repetition maximum (1RM), progressively increasing from 70% (weeks 1-3) to 80% (weeks 4-6).

Other: Resistance Training (High-Intensity); Other: Normoxia

Low-intensity strength training in normoxia

ACTIVE COMPARATOR

Participants performed resistance training in normal oxygen conditions, using lower mechanical loads (20-30% 1RM) following a structured repetition scheme of 30/15/15/15 repetitions per session. Training intensity was progressively increased from 20% (weeks 1-3) to 30% (weeks 4-6).

Other: Resistance Training (High-Intensity); Other: Normoxia

High-intensity strength training in hypoxia

EXPERIMENTAL

Participants conducted resistance training in normobaric hypoxia (simulated altitude \~3500 m; \~13.5% FiO₂), performing 4 sets × 10 repetitions at 70-80% 1RM, progressively increasing load from 70% (weeks 1-3) to 80% (weeks 4-6).

Other: Resistance Training (High-Intensity); Other: Normobaric Hypoxia

Low-intensity strength training in hypoxia

EXPERIMENTAL

Participants completed resistance training in normobaric hypoxia (simulated altitude \~3500 m; \~13.5% FiO₂), employing a repetition scheme of 30/15/15/15 per session at 20-30% 1RM, with intensity progression from 20% (weeks 1-3) to 30% (weeks 4-6).

Other: Resistance Training (Low-Intensity); Other: Normobaric Hypoxia

Interventions

Resistance Training (High-Intensity) OTHER

Leg press exercise performed at 70-80% of 1RM, structured as 4 sets × 10 repetitions, with controlled tempo and standardized rest intervals (2 minutes).

High-intensity strength training in hypoxia; High-intensity strength training under normoxic conditions (H-N); Low-intensity strength training in normoxia

Resistance Training (Low-Intensity) OTHER

Leg press exercise performed at 20-30% of 1RM, structured as 4 sets (30/15/15/15 repetitions), with controlled tempo and shorter rest intervals (1 minute).

Low-intensity strength training in hypoxia

Normobaric Hypoxia OTHER

Environmental intervention simulating an altitude of approximately 3500 meters (\~13.5% FiO₂) using a normobaric hypoxic chamber.

High-intensity strength training in hypoxia; Low-intensity strength training in hypoxia

Normoxia OTHER

Training under normal atmospheric oxygen conditions (\~20.9% FiO₂).

High-intensity strength training under normoxic conditions (H-N); Low-intensity strength training in normoxia

Eligibility Criteria

• Age: 18 Years - 35 Years
• Gender Eligibility Details: Eligibility is restricted to participants who are biologically male and self-identify as male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Male professional-level ice hockey athletes (Napród Janów HC).
• Age range: 18-30 years.
• Minimum of 3 years of consistent professional level ice hockey training experience.
• No history of significant injury or illness within the previous 3 months.
• Able and willing to comply with all study procedures, including adherence to --scheduled training sessions and assessments.
• Provision of written informed consent to participate.

You may not qualify if:

• Current or recent (within past 3 months) musculoskeletal injuries or conditions that would limit participation in resistance training.
• Presence of cardiovascular, metabolic, respiratory, or neuromuscular disorders that may pose risk or interfere with performance assessment or training.
• Current participation in another structured hypoxic training protocol or simultaneous research intervention.
• History of altitude-related illness or known adverse reactions to hypoxic exposure.
• Use of any medications or supplements known to significantly influence muscular performance or recovery within four weeks prior to study initiation.

Sponsors & Collaborators

• The Jerzy Kukuczka Academy of Physical Education in Katowice: lead
• Ministry of Science and Higher Education, Poland: collaborator

Study Sites (1)

Jerzy Kukuczka Academy of Physical Education in Katowice

Katowice, Silesian Voivodeship, 40-065, Poland

Location

MeSH Terms

Interventions

Resistance Training

Intervention Hierarchy (Ancestors)

Exercise Therapy; Rehabilitation; Aftercare; Continuity of Patient Care; Patient Care; Therapeutics; Physical Therapy Modalities; Physical Conditioning, Human; Exercise; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 8, 2025
• First Posted: April 16, 2025
• Study Start: April 25, 2025
• Primary Completion: May 10, 2025
• Study Completion: June 1, 2025
• Last Updated: April 16, 2025

Record last verified: 2025-04

Data Sharing

• IPD Sharing: Will not share

Locations

PL (1)