Long-term Adaptations of Skeletal Muscle After Hybrid Training.

NCT ID: NCT07341711

Last Updated: 2026-01-14

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2026-01-08
• Study Completion Date: 2026-12-20

Brief Summary

Obesity is a major challenge for public health and renders it imperative to reduce its prevalence. High intensity interval training (HIIT) is a form of exercise training that can efficiently induce weight loss in adults with overweight or obesity, even in the absence of dietary intake manipulation. Hybrid type training represents a form of HIIT, that incorporates both cardiorespiratory and musculoskeletal stimuli, by combining multiple types of exercise into a circuit-type, interval style workout. Recent evidence suggests that long-term participation in hybrid HIIT results in significant health-related benefits. However, the molecular mechanisms driving the chronic effects of hybrid HIIT on cardiometabolic and musculoskeletal health remains to be elucidated.

Detailed Description

A total number of 30 adults (both males and females) aged 30-50, meeting the inclusion criteria, will be enrolled in this study. Participants will be randomly assigned to either (i) a Control group or (ii) an Intervention group. The Intervention group will participate in three hybrid-type HIIT sessions per week over a 6-month period while receiving a balanced diet. The Control group will receive a balanced diet over the 6-month period but will not participate in exercise training. At baseline and 6 months, both groups will undergo assessment of their anthropometric profile, body composition, resting metabolic rate, muscle strength and cardiorespiratory capacity and provide resting blood and skeletal muscle samples.

Conditions

Obesity & Overweight

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

Intervention group

Participants in this arm will participate in three hybrid-type HIIT sessions per week over a 6-month period while receiving a balanced diet

Group Type: EXPERIMENTAL

Exercise training

Intervention Type: OTHER

Participants will perform a six-month hybrid training program while receiving a balanced diet. The periodization of hybrid training intervention will consist of three 2-month phases of gradually increased exercise intensity and volume. In every training will participate 5-8 individuals. The training will contain 6-12 different exercises (stations), depending on the phase of the intervention, which will be executed in a circuit for a total of 2-3 rounds, with 2-3 minutes of rest period between sets (depending on the phase). The exercise execution will last 20-45 seconds, and the rest between them will last 30-60 seconds (depending on the phase), while the exercise intensity will range from 75 to 85% of maximal heart rate. The stations of hybrid training will contain multi-joint exercises or neuromuscular activation exercises using either body weight resistance or portable equipment.

Control group

Participants in this arm will receive a balanced diet over the 6-month period but will not participate in exercise training

Group Type: ACTIVE_COMPARATOR

Control group

Intervention Type: OTHER

Participants will receive a balanced diet but will not participate in any type of exercise training over a six month period.

Interventions

Exercise training

Participants will perform a six-month hybrid training program while receiving a balanced diet. The periodization of hybrid training intervention will consist of three 2-month phases of gradually increased exercise intensity and volume. In every training will participate 5-8 individuals. The training will contain 6-12 different exercises (stations), depending on the phase of the intervention, which will be executed in a circuit for a total of 2-3 rounds, with 2-3 minutes of rest period between sets (depending on the phase). The exercise execution will last 20-45 seconds, and the rest between them will last 30-60 seconds (depending on the phase), while the exercise intensity will range from 75 to 85% of maximal heart rate. The stations of hybrid training will contain multi-joint exercises or neuromuscular activation exercises using either body weight resistance or portable equipment.

Intervention Type: OTHER

Control group

Participants will receive a balanced diet but will not participate in any type of exercise training over a six month period.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• BMI: >25 kg/m2 and <40 kg/m2
• Untrained individuals (abstain >1 year from exercise training)
• No dietary intervention over the last 6 months preceding the study
• Low cardiorespiratory fitness level (VO2max: <45 ml/kg/min)
• No use of any medication, dietary supplements
• Low risk for cardiovascular disease
• A weight loss <10% over the last 6 months preceding the study
• Fee of non-communicable diseases (excluding metabolic syndrome)

Exclusion Criteria

• Low participation rate (<80% completion of the exercise training sessions)
• Unbalanced diet
• Participation in additional exercise training regimes
• Cosumption of anti-inflammatory of pain relief medication

• Minimum Eligible Age: 30 Years
• Maximum Eligible Age: 50 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Thessaly

OTHER

Sponsor Role: lead

Responsible Party

Ioannis G. Fatouros

Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Department of Physical Education and Sport Science Trikala, University of Thessaly

Trikala, Thessaly, Greece

Countries

Greece

Central Contacts

Ioannis G Fatouros, Professor

Role: CONTACT

ifatouros@pe.uth.gr

24310 47047 ext. 0030

Facility Contacts

Ioannis G Fatouros, Professor

Role: primary

ifatouros@uth.gr

+30 2431047047

Athanasios Z Jamurtas, Professor

Role: backup

ajamurt@uth.gr

+30 2431047054

Other Identifiers

2482/4.12.2024

Identifier Type: -

Identifier Source: org_study_id