The Effects of Age on Spine Stiffness

Listen to Tara on CFRC's GradChat Radio Program:

Grad Chat Interview (Note: Tara's Interview is the second half of this segment - starting at 13:20)

Purpose

The purpose of this study is threefold:An older woman leans forward, rubbing her back

  1. To determine whether the spine gets stiffer as we age, and to investigate different mechanisms through which this might occur.
    • Age will be defined in two ways:
      • Chronological Age: Based on the date of birth (Traditional Approach)
      • Fitness Age: Based on performance on a battery of fitness tests.
        • Aimed at targeting overall health to give an indication of health of tissues, regardless of the person's age
  2. To determine whether the changes seen in spine stiffness with age affect spine health while sitting.
    • Previous research has show that spine stiffness is affected by prolonged sitting (as seen in office workstations)
      • These changes in spine stiffness are different between males and females, but they have never been investigated as a factor of age.
    • This study will identify whether these changes are systematic based on tissue health, and whether increased tissue age leaves a person at an increased risk for injury in the workplace
      • Tests will be identified that can give an idea of a person's spine stiffness in an attempt to use these tests to prevent injury in the workplace.
        • If a person can monitor their own spine health, they can try to maintain a healthy spine in order to prevent injury
  3. To determine whether certain lifestyle factors affect Fitness Age thereby affecting tissue health more than other lifestyle factors.
    • If we can identify certain factors that will lead to accelerated aging of the tissues (i.e. smoking or drinking), attempts can be made to raise awareness of these factors and focus on reversing their effect on tissue age through training and exercise.

Methods

Two custom-built devices were constructed for this study:

The participant sits in teh device with a weight suspended from the front and back of a harness, which is secured over their chest.

Active Stiffness Testing: The participant adopts a semi-seated position in the device with a harness secured over their chest.  A weight is suspended from the front and back of the harness.  One at a time, the weights are dropped.  The remaining attached weight causes a perturbation to the participant, who must then respond by returning to their upright seated position.  The stiffness of the spine will be estimated based on the participants' response to this perturbation.  A "stiffer" individual will react more quickly and a travel a shorter distance than a more "lax" individual.  We will also monitor the muscle activity throughout this test to determine whether the change in stiffness seen is actually a dampened muscle response, or whether the tissues themselves resulted in the values seen.

The participant lays on a surface and is pulled into a forward bend position.

Passive Stiffness Testing: The participant lays on a movable platform which sits on a surface of ball bearings.  This allows the researcher to move the participant into a flexed position by pulling on a cable attached to the platform.  The maximum flexion angle achieved, as well as the force required to obtain that angle are recorded and are used to estimate the participants' spine stiffness.  A "stiffer" individual will require more force and will flex less than a more "lax" individual.

Implications

If we can identify how stiffness is developed in the low back as we age, we can make attempts to prevent/reverse this phenomenon.  By determining what is the pathway by which this stiffness manifests, as well as which lifestyle factors are most responsible, we may be able to maintain younger, healthier backs for longer, thereby allowing use to work longer without injury.  Additionally, if we can identify a simple test or series of tests that would help us to quickly determine our spine stiffness, we'll be able to monitor it and train to help prevent any age-related changes.

Participation

We are currently recruiting participants for this study!  If you are a sedentary worker (or a student) between the ages of 20-25, 40-45, or 60-65 years of age and are not currently experiencing any back pain and would like to participate, please contact Tara at t.diesbourg@queensu.ca for more information and to schedule your participation.

If you would like more information, please see the following resources:

Recruitment Poster

Letter of Information (Note: this is for information only, you do not have to sign the consent form until you arrive in the lab on your first visit!)