The Effects of High-Intensity Functional Training in Tactical Populations (HIFT)

February 8, 2026 updated by: Shawn M. Arent, University of South Carolina

The Effects of High-Intensity Functional Training Versus Traditional Strength Training or Concurrent Training on Performance and Readiness in Tactical Populations

The purpose of this study is to investigate the effects of high-intensity functional training (HIFT) as compared to traditional resistance training (RT) and concurrent training consisting of RT and high-intensity interval training (HIIT) on physical performance metrics, body composition, and mental and physical readiness of tactical personnel.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This study assesses the impact of 8-weeks of high-intensity functional training (HIFT) as compared to traditional resistance training (RT) and concurrent training consisting of RT and high-intensity interval training (HIIT) on various performance outcomes. The main questions the study aims to answer are:

  • Evaluate the distinct effects of HIFT, RT, and RT plus HIIT over eight weeks on physical performance and body composition measures in tactical men and women.
  • Determine the distress, training load, and physical readiness associated with each of the three distinct training interventions over eight weeks.

Participants will:

  • Take part in 10-weeks total of study-related activity.
  • Complete four total sessions of pre and post-testing sessions, which include body composition, maximal oxygen uptake testing (VO2max), upper and lower body maximal strength, and lower body power.
  • Be randomly assigned to an exercise training intervention.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
44

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • South Carolina
      • Columbia, South Carolina, United States, 29208
        • University of South Carolina Sport Science Lab

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Males and females between the ages of 18 and 35 (inclusive) and enrolled in a reserve officer training corps program.
  • Subject has provided written and dated informed consent to participate in the study.
  • Subject is in good health as determined by medical history and is cleared for exercise.
  • BMI between 17.0 and 29.9 kg/m2.
  • "Good" category or greater for their aerobic capacity according to the American College of Sports Medicine (ACSM) normative data for their age and sex as measured at their baseline visit.

Exclusion Criteria:

  • Participants with any musculoskeletal injuries that would prevent completion of these exercise programs.
  • Participants with any metabolic disorder, including known electrolyte abnormalities, uncontrolled diabetes, uncontrolled thyroid disease, adrenal disease, or hypogonadism.
  • Participants with a history of hepatorenal, musculoskeletal, autoimmune, or neurologic disease.
  • Participants who have lost or gained greater than eight pounds within three months prior to study enrollment.
  • Participants currently taking hyperlipidemic, hypoglycemic, anti-hypertensive, or anti-coagulant medications.
  • Participants who are pregnant or lactating.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: High Intensity Functional Training
Training will include power and strength movements, then 30 minutes of metabolic conditioning training comprised of whole-body multi-joint movements.
Behavioral: High-intensity functional training
Participants assigned to this group will undergo 8 weeks of high-intensity functional training.
Active Comparator: Traditional Resistance Training
This group will perform traditional resistance training.
Behavioral: Traditional resistance training
Participants assigned to this group will undergo 8 weeks of traditional strength and hypertrophy training.
Active Comparator: Concurrent Training
This group will perform traditional resistance training followed by 20 minutes of running, high intensity intervals.
Behavioral: Concurrent training
Participants assigned to this group will undergo 8 weeks of traditional strength and hypertrophy training followed by high-intensity interval aerobic training.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Changes in body composition body fat percentage.
Time Frame: Baseline and Week 10
Body fat percentage via air-displacement
Baseline and Week 10
Changes in body composition fat-free mass.
Time Frame: Baseline and Week 10
Fat-free mass via air-displacement plethysmography.
Baseline and Week 10
Changes in body composition dry fat-free mass.
Time Frame: Baseline and Week 10
Dry fat-free mass via air-displacement plethysmography and bio-electrical impedance.
Baseline and Week 10
Changes in upper body strength.
Time Frame: Baseline and week 10
Upper body strength assessed by 1 repetition maximum bench press.
Baseline and week 10
Changes in lower body strength.
Time Frame: Baseline and week 10
Lower body strength assessed by isometric mid-thigh pulls on bilateral force plates.
Baseline and week 10
Changes in maximal oxygen consumption.
Time Frame: Baseline and week 10
Changes in VO2max measured by maximal graded exercise test with indirect calorimetry.
Baseline and week 10
Changes in ventilatory threshold.
Time Frame: Baseline and week 10
Changes in ventilatory threshold measured by maximal graded exercise test with indirect calorimetry.
Baseline and week 10
Changes in velocity at VO2 max.
Time Frame: Baseline and week 10
Assessed by maximal graded exercise test with indirect calorimetry.
Baseline and week 10

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Internal training load between groups.
Time Frame: Every training session over the 8-week intervention period will be included in this calculation.
Assessed by heart rate chest strap using Edwards training impulse calculation.
Every training session over the 8-week intervention period will be included in this calculation.
Changes in training distress
Time Frame: Baseline, once per week for the 8 training weeks.
Overall training distress and subscales including depressed moods, vigor, physical signs and symptoms, sleep disturbances, perceived stress, and general fatigue using the multicomponent training distress scale, scaled 0 - 110 with higher scores indicating more distress.
Baseline, once per week for the 8 training weeks.
Changes in anaerobic power.
Time Frame: Baseline, once per week for the 8 training weeks.
Measured by countermovement jump through bilateral force plates.
Baseline, once per week for the 8 training weeks.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of South Carolina

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Strength and Conditioning Association

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 26, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 1, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 27, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 29, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 3, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 11, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • Pro00137947

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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