Finding the Optimal Resistance Training Intensity For Your Bones

July 22, 2026 updated by: University of Waterloo

Finding the Optimal Resistance Training Intensity For Your Bones: A Randomized Controlled Trial (FORTIFY Bones)

Osteoporosis is a bone disease that can result in fractures, disability and an increased risk of premature death. Exercise is recommended for fall and fracture prevention, but health care professionals often recommend walking or lower intensity community exercise classes, which may not be effective for building bone. Further, individuals with osteoporosis are often told to avoid lifting or moving in certain ways, which creates fear and activity avoidance. Conversely, research suggests that to stimulate bone, you need higher loads on bone, with either higher intensity resistance training or impact exercise - the types of things people with low bone mass are told to avoid. Our study will examine different types of exercise intensity and how they translate to building bone in people with low bone mineral density (BMD).

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

The FORTIFY Bones study will compare the effect of supervised twice-weekly progressive resistance training (PRT) at moderate or high intensity for one year to a home posture and balance exercise program on lumbar spine bone mineral density (BMD), in individuals with low bone mass not taking osteoporosis medication. As secondary analyses, we will examine the differences between each resistance training intensity and home exercise, and between resistance training intensities on all outcomes. Participants will be randomized to one of three exercise programs to be completed twice weekly: posture and balance exercise program at home, in-person, supervised progressive resistance training at 70% of estimated 1 Repetition Maximum (1RM) intensity, or in-person, supervised progressive resistance training at an 85% estimated 1RM intensity. The study is a multi-centre trial that will take place at the University of Waterloo, Toronto General Hospital, and the University of Saskatchewan. The long-term goal of this study is to generate evidence to support decision-making on the type of exercises for people with osteoporosis.

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.
324

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 Locations

  • Canada
      • Markham, Canada
        • University of Toronto
      • Saskatoon, Canada
        • University of Saskatchewan
    • Ontario
      • Waterloo, Ontario, Canada
        • University of Waterloo

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

50 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 50 or over
  • Has received 2 vaccines for COVID-19

  • Has femoral neck, total hip, or lumbar spine BMD T-score of ≤ -1, OR has been or have a FRAX probability of fracture of greater than or equal to 20% for major osteoporotic fracture or 3% or greater for hip fracture.*

    • Individuals at high risk of fracture (i.e., risk in next 10 years is >20% according to FRAX) should be offered medication for osteoporosis. We will only include individuals at high risk of fracture who have declined medication or who had been on osteoporosis medication and decided to cease taking it in the appropriate timeline (as outlined by PI's and Physician).
  • Willing to participate in 2x weekly exercise sessions
  • Self-reported as postmenopausal for ≥ 2 years, OR postmenopausal stats confirmed via blood test (female participants only)

Exclusion Criteria:

  • Is unable to communicate in English
  • Has conditions affecting bone health
  • Takes or has taken medications affecting bone in the last 12 months or longer (as determined by the research team)
  • Has had a clinical or symptomatic spine fracture in the last 12 months, or a lower/upper limb fracture in the last 6 months
  • Has had a joint replacement in the last 6 months
  • Is receiving palliative care
  • Has major surgery planned in the next 12 months
  • Has had cancer within the last 2 years (excluding non-melanoma skin cancer)
  • Has planned travel time of greater than 6 weeks
  • Has been diagnosed with dementia
  • Is already participating in moderate- or high-intensity progressive resistance training ≥ twice weekly
  • Weighs over 450 lbs
  • Has contraindications to resistance training

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

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.
Active Comparator: Home exercise
Home exercise program, with biweekly group virtual education and exercise classes.
Other: Home exercise
Participants in this arm will complete twice-weekly upper and lower body exercises at home, focused on posture and balance. Participants will meet 1:1 with an exercise physiologist who will select and prescribe exercises. Participants will also be invited to attend twice monthly virtual exercise and education sessions.
Experimental: Supervised strength training (group 1)
In-person, supervised muscle strengthening exercises twice weekly at a specific intensity.
Other: Supervised strength training (group 1)
Participants in this arm will complete twice weekly resistance training. They will focus on form initially, and then be progressed to 3 sets of 10-12 repetitions at an intensity of ~70% of estimated 1 repetition maximum.
Experimental: Supervised strength training (group 2)
In-person, supervised muscle strengthening exercises twice weekly at a specific intensity.
Other: Supervised strength training (group 2)
Participants in this arm will complete twice weekly resistance training. They will focus on form initially, and then be progressed to 3 sets of ~4-6 repetitions at an intensity of 85% of estimated one repetition maximum, with a warm-up set of 8 repetitions at their estimated 70% estimated one repetition maximum to attempt to match the volume performed in the other resistance training group.

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
Lumbar Spine bone mineral density (BMD)
Time Frame: Baseline and 12 months
Lumbar spine (L1-L4) bone mineral density measured via dual-energy X-ray Absorptiometry (DXA) scan.
Baseline and 12 months

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
Fractures
Time Frame: Over 12 months
Composite outcome of new non-vertebral and vertebral fractures, and progression of existing vertebral fractures. We will report the number in each category separately. We will use a fracture questionnaire for non-vertebral fractures, and vertebral fractures that come to clinical attention. Participants will undergo a DXA scan for Vertebral Fracture Assessment (VFA) at baseline and the 12-months. A vertebral fracture will be defined as having a radiographic presence of ≥25% reduction in anterior, middle, or posterior vertebral height, verified by an experienced radiologist at University Health Network via the Genant visual semi-quantitative method. Baseline VFA will be assessed for vertebral fractures and compared to VFA at 12 months to ascertain if there has been progression of new fractures; progression will be defined as progression to a new Genant level or a change in height of at least 10%.
Over 12 months
Appendicular lean mass
Time Frame: Baseline and 12 months
We will calculate appendicular lean mass (kg) and its index (kg/m^2) from appendicular bone-free lean mass and height (cm).
Baseline and 12 months
Height
Time Frame: Baseline and 12 months
Height will be a proxy measure of posture.
Baseline and 12 months
Occiput-to-wall distance
Time Frame: Baseline and 12 months
Occiput-to-wall distance will be a proxy measure of posture.
Baseline and 12 months
Knee extension peak torque
Time Frame: Baseline, 6 months, and 12 months
We will assess isometric knee extension peak torque using a knee extension test with a dynamometer.
Baseline, 6 months, and 12 months
30 Second Chair Stand Test.
Time Frame: Baseline, 6 months, and 12 months
We will use the 30 Second Chair Stand Test.
Baseline, 6 months, and 12 months
Four Square Step Test
Time Frame: Baseline, 6 months, and 12 months
We will use the Four Square Step Test to assess lower extremity muscle power and dynamic balance during functional tasks.
Baseline, 6 months, and 12 months
Grip Strength
Time Frame: Baseline, 6 months, and 12 months
We will assess grip strength of the non-dominant arm using a hand dynamometer.
Baseline, 6 months, and 12 months
10 Metre Walk Test.
Time Frame: Baseline, 6 months, and 12 months
We will assess gait speed using the 10 Metre Walk Test.
Baseline, 6 months, and 12 months
6 Minute Walk Test.
Time Frame: Baseline, 6 months, and 12 months
We will assess endurance using the 6 Minute Walk Test.
Baseline, 6 months, and 12 months
Serious adverse events
Time Frame: Over 12 months
We will ask participants to report adverse events, using Health Canada definitions. We will report all serious and non-serious adverse events and identify those attributable to intervention. Safety outcomes will include all falls, fractures, and serious and non-serious adverse events. Any fractures or falls that are attributable to intervention will be considered under both fall or fracture outcomes, and harms.
Over 12 months
Non-serious adverse events
Time Frame: Over 12 months
We will ask participants to report adverse events, using Health Canada definitions. We will report all serious and non-serious adverse events and identify those attributable to intervention. Safety outcomes will include all falls, fractures, and serious and non-serious adverse events. Any fractures or falls that are attributable to intervention will be considered under both fall or fracture outcomes, and harms.
Over 12 months
Glucose concentration
Time Frame: Baseline and 6 months
We will be taking a fasted blood sample from participants to measure plasma glucose concentrations using biochemical assay. Blood samples will only be collected from participants at the University of Waterloo site.
Baseline and 6 months
Insulin concentration
Time Frame: Baseline and 6 months
We will be taking a fasted blood sample from participants to measure serum insulin concentrations using radioimmunoassay. Blood samples will only be collected from participants at the University of Waterloo site.
Baseline and 6 months
Total Hip BMD
Time Frame: Baseline and 12 months
Bone mineral density of the hip measured via DXA scans
Baseline and 12 months
Femoral Neck BMD
Time Frame: Baseline and 12 months
Bone mineral density of the femoral neck measured via DXA scans
Baseline and 12 months
Trabecular Bone Score
Time Frame: Baseline and 12 months
Trabecular bone score (TBS) will be calculated using TBS iNsight software. A high TBS value indicates high quality boner structure, whereas a low TBS value demonstrates a lower quality structure. The TBS index ranges from 0.9 - 1.6.
Baseline and 12 months
Hip Geometry
Time Frame: Baseline and 12 months
We will use the DXA scanner's hip structural analysis feature to calculate estimates of hip geometry from proximal femur scans.
Baseline and 12 months
Health Service Use
Time Frame: Baseline, 6 months, and 12 months
We will assess direct medical resources (e.g., tests, medications, hospitalization, rehabilitation), direct non-medical resources (e.g., out of pocket expenses, transportation), indirect resources (e.g., iMTA Productivity Cost Questionnaire) and clinical events and management. We will assess resource use for incident falls, fractures or adverse events. Multiplying resources collected by jurisdictional unit costs in Canadian dollars will determine the total cost per exercise program.
Baseline, 6 months, and 12 months
Ratio of costs to QALY
Time Frame: Baseline, 6 months, and 12 months
We will calculate the ratio of incremental costs between the interventions, determined by trial resources, and clinical outcome (QALY) to achieve an incremental cost per life year gained outcome.
Baseline, 6 months, and 12 months
Willingness to pay
Time Frame: Baseline, 6 months, and 12 months
We will assess willingness to pay for various exercise models using a contingent valuation survey.
Baseline, 6 months, and 12 months
Body weight
Time Frame: Baseline, 6 months and 12 months
Body weight in kg measured using scale
Baseline, 6 months and 12 months
Rate of falls per person per year
Time Frame: Over 12 months
Participants will be emailed a falls calendar via a survey at the end of each month. Participants will be asked to immediately report any falls to research assistant and to exercise physiologist. Exercise physiologists will report any noted falls to their study coordinator immediately and additional follow-up documentation will be required. Rate of falls and number of people who experience one or more falls will be compared between groups.
Over 12 months
Number of people who experience one or more falls
Time Frame: Over 12 months
Participants will be emailed a falls calendar via a survey at the end of each month. Participants will be asked to immediately report any falls to research assistant and to exercise physiologist. Exercise physiologists will report any noted falls to their study coordinator immediately and additional follow-up documentation will be required. Rate of falls and number of people who experience one or more falls will be compared between groups.
Over 12 months
Bone-free lean mass
Time Frame: Baseline and 12 months
Whole body fat- and bone-free lean mass will be derived from DXA scans.
Baseline and 12 months
Osteoporosis-specific quality of life (QUALEFFO-41)
Time Frame: Baseline, 6 months, and 12 months
We will use the QUALEFFO-41 as an osteoporosis specific measure of health-related quality of life.
Baseline, 6 months, and 12 months
Quality of life (EQ5D5L)
Time Frame: Baseline, 6 months, and 12 months
We will use the EQ5D5L measure as a generic health-related quality of life measure.
Baseline, 6 months, and 12 months
Pro/anti-inflammatory markers
Time Frame: Baseline and 6 months
We will be taking a fasted blood sample from participants to measure plasma pro- and anti-inflammatory markers using a multiplex kit. Blood samples will only be collected from participants at the University of Waterloo site.
Baseline and 6 months
Oxidative stress markers/antioxidant status (including oxygen radical absorbance capacity (ORAC) assay, protein carbonyls, glutathione peroxidase activity, thioredoxin, malondialdehyde)
Time Frame: Baseline and 6 months
We will be taking a fasted blood sample from participants to measure antioxidant status and markers of oxidative stress using commercially available assays. Blood samples will only be collected from participants at the University of Waterloo site.
Baseline and 6 months
peptides synthesized and released by myocytes in muscle tissue
Time Frame: Baseline and 6 months
We will be taking fasting blood samples from participants to measure peptides synthesized and released by myocytes in muscle tissue via the Luminex Performance Assay. Blood samples will only be collected from participants at the University of Waterloo site.
Baseline and 6 months

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Dietary Intake
Time Frame: Baseline, 6 months, and 12 months
We will use Automated Self-Administered 24-hour dietary assessment tool (ASA24) to collect information on the participant's dietary intake through the self-administered 24-hour dietary record. Participants will report all food and beverage items and quantities on 3 days (2 weekday, 1 weekend day) at baseline, 6 months, and 12 months. We will also use the SCREEN2 tool at baseline only. We will report descriptive data on energy, protein, calcium, and vitamin D intake, and perform exploratory analyses of changes in these outcomes over time. We will perform subgroup analyses: 1) Baseline daily calcium (<1000 vs. >1000 mg per day); and 2) Baseline protein intake (<1.2g/kg body weight per day). We will explore changes in participants who are referred to a dietitian for counselling because of low intakes of protein, calcium, or vitamin D.
Baseline, 6 months, and 12 months

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 Waterloo

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.
University Health Network, Toronto
Canadian Institutes of Health Research (CIHR)
University of Saskatchewan

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Lora Giangregorio, PhD, University of Waterloo

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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.
September 13, 2022

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.
February 28, 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.
February 28, 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).
July 6, 2022

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.
September 12, 2022

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 15, 2022

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.
July 23, 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.
July 22, 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.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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.
  • 41337

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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