StrengthNCT07271108
Carrying Heavy Shopping Bags and Muscle Function
A study testing Experimental: Shopping bag carrying in people with Strength and Strength Training Effects, run by University of Glasgow at 1 site in United Kingdom.
Trial summary
What Is This Study About? To find out whether carrying heavy shopping bags twice a week can help adults not currently meeting physical activity strength guidelines improve muscle mass, strength, power, and endurance. Read more about this study
- Who is it for?
- Ages 16 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- Strength, Strength Training Effects, Resistance Exercise
- What is being tested?
- Experimental: Shopping bag carrying
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 45 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 24 Apr 2023to 16 Jul 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 16 to 75 years
- All sexes
- Healthy volunteers accepted
- Child, Adult, Older adult
Who may be able to join
- Performing less than 2 days per week of muscle strengthening exercise
- Pass the physical activity readiness questionnaire
- Available during data collection period
Who cannot join
- Current or prior history of heart, lung, kidney, endocrine or liver disease or cancer.
- Performing more than 2 days per week of muscle strengthening exercise
- Answered yes to any of the questions in the Physical Activity Readiness Questionnaire
- Available during data collection period
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
university of glasgow, James Black Building Lab
Glasgow, Glasgow City, G12 8QQ
About this study
Official title: The Effect of Carrying Heavy Shopping Bags on Muscle Function and Mass: a Randomized Controlled Trial.
What Is This Study About? To find out whether carrying heavy shopping bags twice a week can help adults not currently meeting physical activity strength guidelines improve muscle mass, strength, power, and endurance.
What Can Be learnt?
Read more
- Can carrying shopping bags help improve muscle mass, strength, power, and endurance?
- Should carrying shopping bags be included within physical activity recommendations?
Two groups will be compared:
- One group will carry shopping bags twice a week within a controlled lab environment
- The other group won't change anything in their routine.
What Will Participants Do?
- Self-select a weight for shopping bags that is heavy but can be carried for 15 minutes to use for all sessions
- Walk with shopping bags for 15 minutes at a normal walking speed for carrying shopping home from the supermarket.
- After each minute, the time stops and participants place bags on the floor. The time restarts for the next minute when the participant chooses to pick up the bags again.
- Conditions
- Strength, Strength Training Effects, Resistance Exercise
- Being tested
- Experimental: Shopping bag carrying
- Keywords
- Health promotion, Resistance training, strength training, carrying shopping
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Experimental: Shopping bag carryingBehavioural
Four-week shopping bag carry intervention (15 mins, 2x per week). Performed under supervision in laboratory.
| Study group | Role | What they receive |
|---|---|---|
| Control - Usual routine | No intervention | Not described |
| Shopping bag carrying | Experimental | Four-week shopping bag carry intervention (15 mins, 2x per week). Performed under supervision in laboratory. Receives: Behavioral: Experimental: Shopping bag carrying |
What is being measured
The primary outcome is the main question the study is designed to answer.
Back strength
Takei Back Strength Dynamometer (T.K.K. 5002 BACK-A Type-3) used to measure back strength to the nearest 1 kg. Measurements taken with the legs, back and arms straight and the torso flexed to 30 degrees at the hip with the handle held in a natural grip. Participants instructed to gradually pull as hard as they could on the handle in order to raise the upper part of their body without bending their knees. Three trials performed with the maximum value used in the analysis.
Measured: Baseline and one week after the intervention ended
Jump Height
Assessed using a countermovement jump with hands on hips. Participants instructed to crouch into a squat position and then jump as high as possible with legs fully extended and landing on the same spot with knees extended and feet together. After a familiarisation attempt, participants to perform three countermovement jumps and the maximum peak power used in the analysis. Jump height and flight time calculated using Microgate Optojump Next software version 1.10.5.0 connected to photoelectric bars RX10 and TX10 (Microgate Optojump Next, Bolzano, Italy) placed parallel to each other.
Jump height derived from the equation: H = g×t2/8 (H = the jump height (m), t = jump flight time (seconds) and g = acceleration due to gravity (9.81 m/s-2))
Measured: Baseline and one week after the intervention ended
Peak Power
Assessed using a countermovement jump with hands on hips. Participants instructed to crouch into a squat position and then jump as high as possible with legs fully extended and landing on the same spot with knees extended and feet together. After a familiarisation attempt, participants to perform three countermovement jumps and the maximum peak power used in the analysis. Jump height and flight time calculated using Microgate Optojump Next software version 1.10.5.0 connected to photoelectric bars RX10 and TX10 (Microgate Optojump Next, Bolzano, Italy) placed parallel to each other.
Peak Power calculated using the Sayers equation: Peak Power (Watts) = 60.7 × jump height (cm) + 45.3 × body mass (kg) - 2055
Measured: Baseline and one week after the intervention ended
Muscle Endurance
Endurance assessed by a 60 second sit to stand test using a 46.5cm high, straight-backed chair with a hard seat and no arm rests. From a seated position with hands on shoulders and arms crossed across the chest, participants instructed to stand up from the chair until their legs were completely straight, then sit back down again (one complete sit to stand) as many times as possible in 60 seconds. The number of complete sit to stands used in the analysis.
Measured: Baseline and one week after the intervention ended
Grip strength
Jamar hydraulic hand dynamometer in handle position II used to measure grip strength to the nearest 1 kg. Measurements taken with the participant seated with feet flat on the floor, elbow flexed 90 degrees by their side and with the wrist just over the end of the arm of the chair in a neutral position (thumbs-up position). Participants instructed to squeeze as hard as possible until the needle stopped rising with the verbal encouragement of "squeeze, squeeze, squeeze and relax". Three trials performed on each side, alternately, with the maximum value used in the analysis in accordance with the Southampton protocol
Measured: Baseline and one week after the intervention ended
Body composition
Assessed using a Body Composition Analyzer Type BC-418 MA (Tanita Corporation, Tokyo, Japan) to determine whole body bioimpedance between the hands and feet by applying a constant current of 90 microamps at 50kHz through the body. Measurements taken in the standing position with bare feet placed on the footplate electrodes and the hand grip electrodes held by the side of the body. Whole body impedance used to derive skeletal muscle mass.
Measured: Baseline and one week after the intervention ended
Secondary outcomes (2)
Distance shopping carried
The number of complete corridor lengths walked with the shopping bags in 15 minutes was recorded for those in the intervention group.
Measured: 2 x per week at every visit throughout the 4 week intervention
Perceived exertion
Perceived exertion was measured using the Borg Rating of Perceived Exertion scale (RPE) [44] from 6-20, with 20 meaning the harderst exertion and 6 the least exertion at the end of each 15-minute carry for those in the intervention group.
Measured: 2 x per week at every visit throughout the 4 week intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Dec 2025
- Study start24 Apr 2023
- Primary completion16 Jul 2025
- Study completion16 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for StrengthStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 45 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Glasgow
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Stuart Gray, University of Glasgow
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07271108
- Sponsor's protocol ID
- 200220195
- Status last verified
- Dec 2025
- First submitted
- 17 Nov 2025
- Last updated
- 9 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Anonymised participant data will be made available by the author upon request. Data and study protocol will be made available as part of publication.
Study at a glance
From the registry record, last updated by the sponsor on 9 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Carrying Heavy Shopping Bags on Muscle Function and Mass: a Randomized Controlled Trial.
- ClinicalTrials.gov ID
- NCT07271108
- Acronym / sponsor ID
- 200220195
- Conditions
- Strength, Strength Training Effects, Resistance Exercise
- Keywords
- Health promotion, Resistance training, strength training, carrying shopping
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 45 participants (actual)
- Lead sponsor
- University of GlasgowUniversity, hospital or other
- Study start
- 24 Apr 2023 (actual)
- Primary completion
- 16 Jul 2025 (actual)
- Study completion
- 16 Jul 2025 (actual)
- First posted
- 9 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
What Is This Study About? To find out whether carrying heavy shopping bags twice a week can help adults not currently meeting physical activity strength guidelines improve muscle mass, strength, power, and endurance.
What Can Be learnt?
- Can carrying shopping bags help improve muscle mass, strength, power, and endurance?
- Should carrying shopping bags be included within physical activity recommendations?
Two groups will be compared:
- One group will carry shopping bags twice a week within a controlled lab environment
- The other group won't change anything in their routine.
What Will Participants Do?
- Self-select a weight for shopping bags that is heavy but can be carried for 15 minutes to use for all sessions
- Walk with shopping bags for 15 minutes at a normal walking speed for carrying shopping home from the supermarket.
- After each minute, the time stops and participants place bags on the floor. The time restarts for the next minute when the participant chooses to pick up the bags again.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Control - Usual routine | No intervention | – |
| Shopping bag carrying | Experimental | Behavioral: Experimental: Shopping bag carryingFour-week shopping bag carry intervention (15 mins, 2x per week). Performed under supervision in laboratory. |
Who may qualify
- Ages
- 16 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (3 listed)
- Performing less than 2 days per week of muscle strengthening exercise
- Pass the physical activity readiness questionnaire
- Available during data collection period
Key exclusion criteria (4 listed)
- Current or prior history of heart, lung, kidney, endocrine or liver disease or cancer.
- Performing more than 2 days per week of muscle strengthening exercise
- Answered yes to any of the questions in the Physical Activity Readiness Questionnaire
- Available during data collection period
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Experimental: Shopping bag carryingFour-week shopping bag carry intervention (15 mins, 2x per week). Performed under supervision in laboratory. | Behavioural | Shopping bag carrying |
Primary outcome
Back strength
Time frame: Baseline and one week after the intervention ended
Takei Back Strength Dynamometer (T.K.K. 5002 BACK-A Type-3) used to measure back strength to the nearest 1 kg. Measurements taken with the legs, back and arms straight and the torso flexed to 30 degrees at the hip with the handle held in a natural grip. Participants instructed to gradually pull as hard as they could on the handle in order to raise the upper part of their body without bending their knees. Three trials performed with the maximum value used in the analysis.
Jump Height
Time frame: Baseline and one week after the intervention ended
Assessed using a countermovement jump with hands on hips. Participants instructed to crouch into a squat position and then jump as high as possible with legs fully extended and landing on the same spot with knees extended and feet together. After a familiarisation attempt, participants to perform three countermovement jumps and the maximum peak power used in the analysis. Jump height and flight time calculated using Microgate Optojump Next software version 1.10.5.0 connected to photoelectric bars RX10 and TX10 (Microgate Optojump Next, Bolzano, Italy) placed parallel to each other. Jump height derived from the equation: H = g×t2/8 (H = the jump height (m), t = jump flight time (seconds) and g = acceleration due to gravity (9.81 m/s-2))
Peak Power
Time frame: Baseline and one week after the intervention ended
Assessed using a countermovement jump with hands on hips. Participants instructed to crouch into a squat position and then jump as high as possible with legs fully extended and landing on the same spot with knees extended and feet together. After a familiarisation attempt, participants to perform three countermovement jumps and the maximum peak power used in the analysis. Jump height and flight time calculated using Microgate Optojump Next software version 1.10.5.0 connected to photoelectric bars RX10 and TX10 (Microgate Optojump Next, Bolzano, Italy) placed parallel to each other. Peak Power calculated using the Sayers equation: Peak Power (Watts) = 60.7 × jump height (cm) + 45.3 × body mass (kg) - 2055
Muscle Endurance
Time frame: Baseline and one week after the intervention ended
Endurance assessed by a 60 second sit to stand test using a 46.5cm high, straight-backed chair with a hard seat and no arm rests. From a seated position with hands on shoulders and arms crossed across the chest, participants instructed to stand up from the chair until their legs were completely straight, then sit back down again (one complete sit to stand) as many times as possible in 60 seconds. The number of complete sit to stands used in the analysis.
Grip strength
Time frame: Baseline and one week after the intervention ended
Jamar hydraulic hand dynamometer in handle position II used to measure grip strength to the nearest 1 kg. Measurements taken with the participant seated with feet flat on the floor, elbow flexed 90 degrees by their side and with the wrist just over the end of the arm of the chair in a neutral position (thumbs-up position). Participants instructed to squeeze as hard as possible until the needle stopped rising with the verbal encouragement of "squeeze, squeeze, squeeze and relax". Three trials performed on each side, alternately, with the maximum value used in the analysis in accordance with the Southampton protocol
Body composition
Time frame: Baseline and one week after the intervention ended
Assessed using a Body Composition Analyzer Type BC-418 MA (Tanita Corporation, Tokyo, Japan) to determine whole body bioimpedance between the hands and feet by applying a constant current of 90 microamps at 50kHz through the body. Measurements taken in the standing position with bare feet placed on the footplate electrodes and the hand grip electrodes held by the side of the body. Whole body impedance used to derive skeletal muscle mass.
2 secondary outcomes
Distance shopping carried
Time frame: 2 x per week at every visit throughout the 4 week intervention
Perceived exertion
Time frame: 2 x per week at every visit throughout the 4 week intervention
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Dec 2025.
- Individual participant dataSharing planned: No. Anonymised participant data will be made available by the author upon request. Data and study protocol will be made available as part of publication.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Experimental: Shopping bag carrying in people with Strength and Strength Training Effects, run by University of Glasgow at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 9 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Back strength (time frame: Baseline and one week after the intervention ended). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Dec 2025.