Long-term Adaptations of Skeletal Muscle After Hybrid Training

Official title

Long-term Adaptations of Skeletal Muscle in Overweight and Obese Individuals After Hybrid Training

Overview

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.

Interventions

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

Primary outcome measures

• Change in mitochondrial size [Time frame: At baseline and at 6 months]
• Change in mitochondrial density [Time frame: At baseline and at 6 months]
• Change in mitochondrial count [Time frame: At baseline and at 6 months]
• Change in mitochondrial distribution [Time frame: At baseline and at 6 months]
• Change in maximum oxygen consumption (VO2max) [Time frame: At baseline and at 6 months]
• Change in muscle fiber cross-sectional area [Time frame: At baseline and at 6 months]
• Change in PAX7+ satellite cells count [Time frame: At baseline and at 6 months]
• Change in total protein content [Time frame: At baseline and at 6 months]
• Change in myonuclei content [Time frame: At baseline and at 6 months]
• Change in peroxisome proliferator-activated receptor-gamma coactivator -1a (PGC-1a) expression [Time frame: At baseline and at 6 months]

Secondary outcome measures (12)

• Change in density and distribution of capillaries [Time frame: At baseline and at 6 months]
• Change in skeletal muscle fiber typing [Time frame: At baseline and at 6 months]
• Change in GLUT-4 protein expression [Time frame: At baseline and at 6 months]
• Change reduced glutathione content in skeletal muscle cells [Time frame: At baseline and at 6 months]
• Change in glutathione peroxidase activity in skeletal muscle cells [Time frame: At baseline and at 6 months]
• Change in glutathione reductase activity in skeletal muscle cells [Time frame: At baseline and at 6 months]
• Change in superoxide dismutase activity in skeletal muscle cells [Time frame: At baseline and at 6 months]
• Change in fasting glucose levels [Time frame: At baseline and at 6 months]
• Change in fasting insulin levels [Time frame: At baseline and at 6 months]
• Change in glycosylated hemoglobin levels [Time frame: At baseline and at 6 months]
• Change in high-density lipoprotein (HDL) levels [Time frame: At baseline and at 6 months]
• Change in low-density lipoprotein (LDL) levels [Time frame: At baseline and at 6 months]

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
• Free 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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Open label

Primary purpose

Other

Study locations

Greece · 1 center

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

Identifiers

NCT: NCT07341711 · 2482/4.12.2024

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗