Acute Effects of High-intensity Interval Aerobic and Functional Training at Different Intensities

Summary

Moderate-intensity physical exercise is widely recognized for its health benefits, yet time constraints limit adherence. High-intensity interval training (HIIT) has gained popularity as a more time-efficient alternative, eliciting significant cardiovascular, respiratory, metabolic, and neuromuscular responses. More recently, functional strength exercises have been integrated into high-intensity training, leading to high-intensity functional training (HIFT) and moderate-intensity functional training (MIFT). However, the acute physiological responses to these modalities remain underexplored compared to traditional HIIT (running or cycling) and strength training. This study aims to assess and compare the acute cardiovascular, metabolic, and neuromuscular responses of HIFT, MIFT, HIIT, and traditional strength training in healthy, physically active adults to inform their potential application in special populations.

Conditions

• High Intensity Interval Training (Cycling)
• High Intensity Interval Training (Running)
• High Intensity Functional Training
• Moderate Intensity Functional Training
• High Intensity Traditional Strength Training
• Moderate Intensity Traditional Strength Training

Interventions

OTHER

High-intensity interval training, running

Six sets of 2-minute runs will be performed at an intensity of 90-95% of the maximal aerobic speed (MAS) on a treadmill. The recovery between each set will be 2 minutes, during which the subject will walk at an intensity of 50-60% of MAS.

OTHER

High-intensity interval training, cycling

Six sets of 2-minute cycling will be performed at an intensity of 90-95% of the maximal heart rate on a stationary bike. The recovery between each set will be 2 minutes, during which the subject will cycle at an intensity of 50-60% of maximal heart rate.

OTHER

High-intensity functional training

Three sets of six repetitions will be performed at 80% of the one repetition-maximum (1-RM) for six exercises. The recovery between exercises will be the minimum time required to switch from one exercise to the next, and between sets, it will be two minutes. Participants will be instructed to move the load as quickly as possible during each repetition.

OTHER

Moderate-intensity functional training

Three sets of six repetitions will be performed at 60% of the 1-RM for six exercises. The recovery between exercises will be the minimum time required to switch from one exercise to the next, and between sets, it will be two minutes. Participants will be instructed to move the load as quickly as possible during each repetition.

OTHER

Moderate intensity traditional strength training

Three sets of six repetitions will be performed at 60% of the 1-RM for six exercises. The recovery after each set will be two minutes of passive rest. Participants will be instructed to move the load as quickly as possible during each repetition.

OTHER

High intensity traditional strength training

Three sets of six repetitions will be performed at 80% of the 1-RM for six exercises. The recovery after each set will be two minutes of passive rest. Participants will be instructed to move the load as quickly as possible during each repetition.

Sponsors & Collaborators

• Hospital Clínico Universitario de Valladolid

  collaborator OTHER

• European University Miguel de Cervantes

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

OTHER

Masking

SINGLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

100 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-10-12

Primary Completion

2027-01-01

Completion

2027-01-31

Countries

• Spain

Study Locations