Please see below for some updates on the 2014 Summit.

Summit Registration is Now Open!

We are off and running – registration for the 2014 Global Summit on the Physical Activity of Children and Youth is now open. Secure your attendance at this must-attend event for anyone whose work touches childhood physical activity.

Go to registration page now

Call For Abstracts is Online

Share your expertise with an international audience and be part of the resolution of the global childhood inactivity crisis.

The call for abstract submissions is now open for oral presentations, promising practice workshops (sharing successes) and poster presentations with either a research or practice focus.

Read More

 RehabCenter, RheumatismFoundationHospital, Heinola, Finland

E-mail: ragnar.viir@ut.ee

M. Pääsuke, Institute of Exercise Biology and Physiotherapy, University of Tartu, TartuEstonia

K. Rajaleid, Center for Health Equity Studies, StockholmUniversity/ Karolinska Institutet, Stockholm, Sweden

*Note: The source for this paper is the 2008 ISU 12^th Annual Symposium – ‘Space Solutions to Earth’s Global Challenges’

Abstract

The aim of this study was to use the upper trapezius muscle as a representative of the musculoskeletal support system to determine the effect on muscle tension due changing from upright position to a lying position and whether this change could be useful in the prevention of musculoskeletal disorders. Twenty two female subjects participated in this study. Myometric measurements of the upper trapezius muscle on both sides of the body were recorded in a standing, sitting and supine position. Changing from upright positions to a supine position reduced the upper trapezius muscle support function by up to one fifth as characterized with diminishing of muscle tone and stiffness. The change in tone and stiffness of the trapezius muscle is of significance to the well being of sedentary workers. Introducing regular brief breaks of simple unchallenging movements while being in a supine position should enhance recovery from prolonged sitting.

1. Background

1.1 Model from History

In his treatise De Motu Animalium the father of modern biomechanics Giovanni Alfonso Borelli stated already 300 hundred years ago:  ‘…muscular tensions inevitably have to be involved in holding posture’ (1). Also, father of occupational medicine Bernardino Ramazzini said the following about causation of clerk’s neck & shoulder complaints: “Yet ’tis certain that in each City and Town, vast Numbers of Persons still earn their Bread by writing. The Diseases of Persons incident to this Craft arise from three Causes: First, constant sitting, secondly, the perpetual Motion of the Hand in the same manner and thirdly, the Attention and Application of the Mind” (2). Ramazzini listed several other maladies related to prolonged sitting.

Great minds didn’t have more or less sophisticated devices like EMG (Electromyograph), MRE (Magnetic resonance elastography) or MYOTON (Myometric measuring device, as fully described by Vain et al. [10]) to characterise skeletal muscle in different functions and its properties. Indeed their tools were those like inspection and palpation, and system-biological deep pondering upon their observations integrability.

How did scientists characterise the skeletal muscle ensuring the sitting posture in 1700. Obviously, there was interest for it. One could use the tactile sense of the fingers and establish the change in e.g. upper trapezius (UT) muscle in between these positions by palpation. The change can clearly be established – palpation, sensing with fingers is a good method. Anybody can make this discovery palpating their own UT muscles in these positions – much in line with Borelli and Ramazzini. Still, the result of the palpation study cannot be shared with other investigators – this is the limitation of the sensing method – that are why it cannot be used in modern scientific research.

After 300 years passed, Ariëns and her colleagues in 2001 (3) used questionnaire study to conclude that sitting position is an independent risk factor for developing neck pain for the people that sit 95% of the working time.

1.2 Model from Space Life Studies

Human is quite an extraordinary mammal in a sense that during the whole life, each day we change the direction of the longitudinal axis relative to most significant environmental factor – the gravitational force. From morning till night our longitudinal axis relative Earth’s radius have to be supported against gravitational force. By night, the situation is changed drastically by 90° when we lie horizontally, which eliminates the need for the vertical support function. Humans spend in this position one third of the lifetime. Lying down works as the most natural recovering intervention to start the next day. If we were to imagine viewing the whole human life during a one-hour movie, the most noticeable activity would be change between (standing,) sitting and lying. If anyone would observe this from outer space, it could be considered a major factor for understanding our physiology.

On the Earth, the approach of horizontal bed rest microgravity simulation studies is based on the same changing of the longitudinal axis by 90°; the rhythm of the change is different. Staying in horizontal position for couple of months without the need to counteract with the gravitational force causes disuse of muscles and osteoporosis in bones as well as numerous other changes in the whole organism also in organ systems and the cellular level; but the applications of the bed rest (BR) research reveal the crucial role of gravity to health (4). In principle, studying the effect of microgravity on life deals with support function qualitative and quantitative loading. Zero-G spaceflight provokes inherent supportlessness condition in human body with its consequences.

1.3 Model from Robots

For biomechanics, design of bipedal robots is mutually stimulating. Their applications represent experiments, which may support or falsify ideas about the organization and function of living motion and support systems. Bipedal robot – being also a model of a human – needs support and locomotion system. Robots must have flexible waist, which together with their legs have to be supplied with muscle-like property of elasticity/damping ability. This gives to robots self-stability and humanoid-like economic smooth gait, the same time diminishing the need of “constant neural” control (5, 6, and 7).

Bipedal walking – a priori most physiological motion series for human – is absent in weightlessness of Space. The floor is absent. Efforts are made with promising results to offset Earth based rhythmic ground reactions with the Dynamic Foot Stimulus device to combat musculoskeletal disorders in microgravity (8, 9).

On the Earth, we should think of lifelong unassisted natural walking as the most harmonically orchestrated function of a human body in synchrony with breathing, heart beating and triggering pleasure giving raise of theta rhythms from hippocampal neurones (10).

2. Study population and methods

2.1 Study population

The participants were 22 employed working female patients with widespread pain in their rehabilitation cycle in Rheumatism Foundation Hospital. Each of the participants gave their informed written consent. The study was vetted by the Ethical Committee of the Päijät–Häme Hospital District to ensure that it was conducted under the terms of the Declaration of Helsinki.

2.2 Methods

In step 1, each participant stood in relaxed position, upper extremities pendent on sides. They were asked to focus on a mark 4 meters away in order to fix the tilt of the head and the angle of the neck. Non-toxic marks were highlighted on the skin above the middle of the upper trapezius belly halfway from the acromion to the seventh cervical (C7) process.

In step 2, a four-legged wooden chair with a padded backrest and seat without armrests, and without height adjustability was used. Each participant sat in a comfortable relaxed upright position, hands in lap. Again, they were asked to focus on a mark 4 meters away descended on the eyes’ level of participants.

In step 3, the participant lay comfortably supine on a padded examination table.

In all steps the myometric measuring device (figure 1), as fully described by Vain et al. (11) Viir et al. (12) and Gavronski et al. (13), was applied to the marks, and 20 consecutive measurements (at an interval of 1–2 seconds between each) were done twice in two series. Participant was allowed to fidget between two measurement series. Then we compared the results obtained in upright positions with those obtained in the supine position. The differences, significant at the 95% level, are reported on the basis of a Student’s t-test.

2.3 Myometry method

Briefly, the Myoton device registers mechanical oscillations of the tissue provoked by the device itself—the testing-end component of the apparatus works also as a sensor for tissue response. An acceleration transducer, situated on the testing-end, allows the muscle deformation evoked by mechanical impact (0.4 N) to be recorded. Because the neural activation of the skeletal muscle may occur after 25 ms and the properties of the muscle may change (13), the duration of the impact is set at 15 ms to avoid neural reactions and nonelastic deformations of the tissue. In response to the given impact, the tissue (in our case, muscle tissue), together with the testing end, performs natural damping oscillations, governed by the viscoelastic properties of the biological tissue.

Whereas electromyography registers the parameters of electrical activity of the skeletal muscle, the parameters measured by the Myoton device reflect the conditions (i.e., the workability restoration time of muscles during work and after it), and the character of mechanical tension transmission from the sarcomere to the bone levers (15).

Figure 1. The Myoton device and the myometric method (illustration designed by Ivo-Ott Hirvesoo). The principle of myometry lies in giving the muscle under investigation a dosed local mechanical impulse shortly followed by quick release, and recording the mechanical response of the muscle. [Figure reprinted with the permission of Journal of Mechanics in Medicine and Biology [12] and the World Scientific Pub­lishing Co Pte, Ltd, Singapore]

At Home

1. Hide your remote. If you must watch TV, at least stand up to change the channel.
2. When cooking or baking, ditch the hand mixer and use a wooden spoon instead.
3. Take each family member’s laundry upstairs separately.
4. When tidying up, put things away in multiple small trips rather than one big haul.
5. Chop fresh vegetables instead of buying frozen ones.
6. Invest in quality pots and pans; the heavier they are, the more energy it’ll take to use them.
7. Paint, hang curtains, or finish any other home-improvement task on your to-do list.
8. Stand up and march during your favorite TV shows. (Try our Couch-Potato Workout.)
9. Rather than yell toward family members in other rooms, walk over to talk.
10. Stand while styling your hair and putting on makeup.
11. Walk around your home, yard, or neighborhood while on the phone.
12. Hand-wash dishes instead of using the dishwasher.
13. Wash your car instead of taking it through the car wash.
14. Put most-used items on top or bottom shelves so you have to reach for them.
15. Leave your cell phone in one location, so when you need it, you must go to it.
16. Start a compost pile in your yard.
17. Help your kids clean their rooms.
18. Organize a closet.
19. Rake the leaves as a family.
20. Give the delivery guy a break; when you order food in, pick it up yourself.
21. Take a shower instead of a bath.
22. Walk to the mailbox instead of checking the mail from your car.
23. Plant or weed a garden or care for indoor plants.
24. Ask for the paper to be left at the end of your driveway instead of by your front door.
25. Give your dog a bath instead of paying someone else to do it.
26. Instead of sitting and reading, listen to books on tape as you walk, clean, or garden.
27. Preset the timer on your TV to turn off after an hour to remind you to do something more active.
28. Slide a small trampoline under your couch and pull it out for Real Housewives marathons.
29. Put up more Christmas lights.
30. The next time it snows, up your karma and shovel your neighbor’s sidewalk too.
31. Turn on tunes and dance while cooking.

Earlier this year SBRN published an updated definition of the terms “sedentary” and “sedentary behaviour”, which was published in the journals Applied Physiology, Nutrition and Metabolism and Movement & Sport Sciences – Science & Motricité.  The definition was originally published in both English (here) and French (here).  The definition has now been translated into Spanish and Portuguese by Ana Lúcia André with help from Verónica Varela Mato.

You can find links to the translated definitions below.

• Spanish Definition
• Portuguese Definition

The definition can be cited as:

Sedentary Behaviour Research Network. 2012. Standardized use of the terms “sedentary” and “sedentary behaviours”.  Appl Physiol Nutr Metab. 37: 540–542.

If you are interested in helping to translate this definition of sedentary behaviour into another language, please contact us through our contact page.

Curtin University is the largest university in Western Australia with a strong international focus. The School of Physiotherapy has a reputation for world class applied research and multidisciplinary collaborations. A growing number of research projects have been developed around sedentary behaviour/physical activity, technology and health – for example interventions for children and adolescents, interventions for office workers and large longitudinal epidemiological studies in children/young adults and ‘baby boomers’. These projects are mainly funded by the National Health and Medical Research Council of Australia and involve collaborations with researchers across Australia as well as Europe and North America. The research group is expanding and this creates an exciting opportunity for early career postdocs to join the team and develop as emerging leaders.

We are looking for enthusiastic, competent candidates able to work well with colleagues. Clear, critical thinking, strong conceptual and analytical background, and excellent writing skills are important, along with experience in sedentary behaviour and physical activity measurement. An earned doctorate in a related discipline is required along with strong letters of support from three colleagues/supervisors.

The role will include working with the team on existing projects to capture high quality data, data processing and analyses, and preparing and leading manuscripts and conference presentations. The role will also provide opportunities to develop grant writing and student supervision skills. Postdocs will be mentored by the team and encouraged to develop their own related research interests.

The appointment opportunities are flexible with 1-3 year contracts available. Competitive remuneration commensurate with qualifications will be provided (AUD70,000-80,000pa) along with leave and superannuation entitlements.

Further information is available from: Professor Leon Straker (L.Straker@curtin.edu.au) and Dr Rebecca Abbott (rebecca@hms.uq.edu.au; 14thDecember – 21stJanuary 2013 while Leon is on leave)

Click here for further background information on the post-doc positions.

Recently, a letter to the editor by Ragnar Viir and Alar Veraksitš was published in Applied Physiology, Nutrition and Metabolism where concern with SBRN’s proposed definition of sedentary behaviour was expressed. The letter can be read in full here.

Dr. Mark Tremblay, a founding member of SBRN, has responded to this letter and his response can be read in full here.

Click here to download notes from the meeting.

Below is a list of presentations by SBRN members in chronological order.  If you would like to add your presentation to the list, or if you spot an error, please send me a message at tsaunders (at) cheo.on.ca.  You can find the full ICPAPH program and book of abstracts here.

See you in Sydney!

Wednesday, October 31:

Sophie O’Connell

Jeff Valance

Erica Hinckson

Dale Esliger

Andrew Atkin

Natalie Pearson:

Thursday, November 1:

Mette Aadahl

Ingrid Hendriksen

Stuart Biddle:

Dylan Cliff

Travis Saunders

Matthew Buman

Dylan Cliff

Gemma Ryde

Bronwyn Clark

Sebastien Chastin

Friday, November 2

Katrien Wijndaele

Maike Neuhaus

Gemma Ryde

Anne Grunseit

Erica Hinckson

Sebastien Chastin

Hayley Christian

Stuart Biddle

Valerie Carson

Mark Tremblay

Mette Aadahl

Saturday, November 3

Kylie Hesketh

Cindy Gray

Drs Viir and  Veraksitš write:

We welcome the proposal by Sedentary Behaviour Research Network (2012) to define standard terms whereby to describe our researches into the modern problem of excessive sitting. However, we have some concerns. Neither standing nor sitting can adequately be described just in terms of energy expenditure or neuromuscular activity. We must also include the seemingly subtle but measurable and significant effect of gravity on those muscles holding the body upright (Viir et al. 2007; Veraksitš et al. 2012).

Furthermore, if one defines “reclining” as lying down, then that is not “sedentary behaviour” at all; on the contrary, it has the crucial function of obtaining relief from the above effort, as we have shown (Viir et al. 2007; Veraksitš et al. 2012), and this has important application in rehabilitation (Viir et al.
2008).

For our research to be thorough it is important to be alert to the significant effect of gravity, subtle though it may be.

In response to this comment, Dr Mark Tremblay wrote:

I appreciate the concerns expressed by Drs. Viir and Veraksitš. They raise an important point regarding the effects of gravity on physiological functions while in different postures. Furthermore, nuances on how to define “reclining” are raised. The proposal by SBRN that sedentary behaviour be defined as any waking behaviour characterized by an energy expenditure ≤1.5 METs while in a sitting or reclining posture does not disregard the potential importance of gravity or other mechanical (e.g., pressure on tissues of contact points from sitting or type of clothing being worn) or environmental (e.g., indoor vs. outdoor) factors that may provoke, mediate, or moderate physiological or even cognitive functions. Nor does the definition preclude the study of sedentary behaviours such that perhaps a whole “family” of sedentary behaviour subcategories may emerge based on their physiological influence.

The fact that this discussion is occurring is evidence that our earlier letter is achieving its objective and that the mission of SBRN is being successfully pursued. Thanks and please keep the discussion going!

Both articles are available via the website of Applied Physiology, Nutrition and Metabolism.