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Mechanical Load on the Shoulders While Carrying a Backpack- Towards a Knowledge-Based Backpack Design

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified February 2010 by Sheba Medical Center.
Recruitment status was:  Not yet recruiting
Tel Aviv University
Information provided by:
Sheba Medical Center Identifier:
First received: February 3, 2010
Last updated: February 9, 2010
Last verified: February 2010

Soldiers and recreational backpackers are often required to carry heavy loads on their body during military operations or hiking. Despite the advances in backpack design, the loads carried by soldiers still impose an extreme physiological strain (soft tissue deformation) which frequently results in discomfort, pain,musculoskeletal injuries, and loss sensorimotor function.

In the current study, characterization of the pressures, evaluation of the deformations of the soft tissues, specifically the fat, muscles, Brachial plexus and subclavian vessels applied on the shoulder while sitting with a heavy backpack will performed. The data acquired in the current trials will be used for development of a finite element (FE) 3D shoulder model. The purpose is to better understand the mechanical loads that are being transferred to the underlying tissue below the shoulder straps during walking/marching with a backpack. During the 2nd phase of this project, data collected during this research will be used to develop gear that will alleviate the strain on the shoulders, prevent injury, and enhance performance.


  • High focal strain (hot-spots) on the shoulder tissue that are observed with the pressure mapping will be observed also in the MR scans.
  • The strain at those hot-spots can be reduced by personal-geometry adjusted straps.


Five young (18-30 yrs), healthy, and fit males will participate in this study.

Trials design

  1. MR Scans- The scan will be performed for analysis of personal shoulder anatomy, and will be used for developing a 3D FE model. The sagittal view will be used to develop the 3D model. The coronal and axial sectional views will be used to assess the deformations applied on the shoulder tissue. The scan will then be repeated while carrying a 25 kg standard commercial backpack while sitting in the same position, for the assessment of shoulder girdle tissues deformations. Time estimation for each scan is 40 min (80 min total). The subjects are not required to carry the backpack prior to those scans.
  2. Static pressure measurement- each volunteer will be asked to sit for 30 seconds while carrying the 25 kg backpack. During this session, pressure will be measured using a pressure mapping pad (Sensor Products Inc., USA) placed between the shoulder strap and the underlying tissue.

The maximal total participation time of each volunteer will be 2 hours total (inside and outside the MR).

Data acquired in the current trials will be used for the development of a FE (finite element) 3D shoulder model. MR scans will be utilized for composing geometry and for the boundary conditions assessment (strain magnitude). Pressure measurements will be used as boundary conditions (stress magnitude).

MR scans and pressure measurements will be performed in the Sheba medical center facilities.

Healthy Strain

Study Type: Observational
Study Design: Observational Model: Case-Only
Time Perspective: Prospective
Official Title: Mechanical Load on the Shoulders While Carrying a Backpack- Towards a Knowledge-Based Backpack Design

Further study details as provided by Sheba Medical Center:

Estimated Enrollment: 5
Study Start Date: February 2010
Estimated Study Completion Date: April 2011
Estimated Primary Completion Date: January 2011 (Final data collection date for primary outcome measure)
young and fit
5 healthy subjects, age lower than 30 yrs and high physical fitness


Ages Eligible for Study:   18 Years to 30 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

Five young (18-30 yrs), healthy, and fit males will participate in this study. Prior to signing a consent form, the PI will explain to the subjects about the MRI that they are about to participate in if they will decide to sign including all the discomforts involved in this study. For subjects that don't have contraindications for MRI there are no reported risks.

The subjects will be informed that each one of them is free to decide, and is free to stop his participation any time he wishes to.


Inclusion Criteria:

  • 18-30 yrs
  • healthy
  • fit
  • males

Exclusion Criteria:

  • contraindications for MRI
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01066975

Contact: Nogah Shabshin, MD 972 52 6666652
Contact: Amir Hadid, BSc 972 57 8119887

Sheba Medical Center Not yet recruiting
Ramat Gan, Israel
Contact: Amir Hadid, BSc    972 57 8119887   
Sub-Investigator: Amir Hadid, BSc         
Sponsors and Collaborators
Sheba Medical Center
Tel Aviv University
Study Director: Amir Hadid, BSc Sheba Medical Center
  More Information

Responsible Party: Nogah Shabshin, Sheba Medical Center Identifier: NCT01066975     History of Changes
Other Study ID Numbers: SHEBA-10-7645-NS-CTIL
Study First Received: February 3, 2010
Last Updated: February 9, 2010

Keywords provided by Sheba Medical Center:
loaded backpack
unloaded backpack processed this record on August 16, 2017