NCT07498608

Effects of Polarized and Threshold Intensity Distribution Models on Race Time and Body Composition in Recreational Runners Aged 20-45 Years.

Effects of Polarized and Threshold Intensity Distribution Models on Race Time and Body Composition in Recreational Runners Aged 20-45 Years: a Randomized Controlled Trial

• Status: Enrolling By Invitation
• Phase: N/A
• Study type: Interventional
• Enrollment: 20 (estimated)
• Sponsor: Universidad Pedagogica Nacional, Colombia · Academic / Other
• Sex: All
• Age: 20 Years – 45 Years
• Healthy volunteers: Accepted

Summary

This study aims to compare the effects of two intensity distribution training (TID) models-polarized and threshold-on 5-km race time and body composition in recreational runners aged 20 to 45 years. Participants will be randomly assigned to one of two groups and will complete a 12-week structured training program. The primary outcome will be 5-km race time, while secondary outcomes will include changes in body composition. Assessments will be conducted before and after the intervention period.

Detailed description

This randomized controlled trial will investigate the effects of two different intensity distribution training (TID) models: polarized (POL) and threshold (THR), on race time and body composition in recreational runners. A total of 40 participants aged between 20 and 45 years will be randomly assigned to either the POL group or the THR group. Both groups will complete a 12-week training intervention. The polarized model will emphasize a high volume of low-intensity training (Zone 1) with small amounts of high-intensity work (Zone 3), while the threshold model will include a greater proportion of training at moderate intensity (Zone 2). The primary outcome will be 5-km race time measured in minutes/seconds. Secondary outcomes will include body composition variables such as body fat percentage and lean mass. Assessments will be conducted at baseline and after the 12-week intervention. The study aims to determine whether polarized training produces superior improvements compared to threshold training in recreational runners.

Conditions

• Physical Activity
• Physical Activity Intensity
• Physical Activity in Adults
• Running
• Running Performance
• Running Endurance

Interventions

Type	Name	Description
OTHER	Polarized intensity distribution model	Regarding the intervention, it will last 12 weeks, a period during which physiological adaptations to endurance training occur, as Neuman (1994) states with chronological cycles of 8 to 12 weeks. For the TID POL model, the intensity distribution was as follows: Zone 1 (80%), Zone 2 (5%), and Zone 3 (15%). The training periodization for the two TID models was designed using a 3:1 weekly block structure, meaning three weeks of training followed by one week of recovery. The weekly training frequency will consist of four running sessions, each including 10 minutes of running technique drills and two strength training sessions. The running sessions will have the same training volume across the three blocks, which span weeks 1-3, 5-7, and 9-11. The first week of each block will have a volume of 240 minutes, the second week 300 minutes, and the third week 360 minutes. Recovery weeks 4, 8, and 12 will have a volume of 180 minutes.
OTHER	Threshold intensity distribution model	Regarding the intervention, it will last 12 weeks, a period during which physiological adaptations to endurance training occur, as Neuman (1994) states with chronological cycles of 8 to 12 weeks. For the TID THR model, the intensity distribution was as follows: Zone 1 (50%), Zone 2 (40%), and Zone 3 (10%), The training periodization for the two TID models was designed using a 3:1 weekly block structure, meaning three weeks of training followed by one week of recovery. The weekly training frequency will consist of four running sessions, each including 10 minutes of running technique drills and two strength training sessions. The running sessions will have the same training volume across the three blocks, which span weeks 1-3, 5-7, and 9-11. The first week of each block will have a volume of 240 minutes, the second week 300 minutes, and the third week 360 minutes. Recovery weeks 4, 8, and 12 will have a volume of 180 minutes.

Timeline

• Start date: 2026-03-16
• Primary completion: 2026-03-29
• Completion: 2026-06-20
• First posted: 2026-03-27
• Last updated: 2026-03-27

Locations

1 site across 1 country: Colombia