Written by Melissa Penman, Physiotherapist

 

If you are a parent, teacher, early childhood educator, or anyone who works closely with children, you may be familiar with the term motor milestones. My goal today is to break down these milestones to help you familiarize yourself with what to keep an eye on, and when it may be time to integrate pediatric physiotherapy into your child’s life!

What Are the Fundamental Motor Skills?

The fundamental motor skills are locomotor skills, postural skills, and object interaction skills. Locomotion skills involve movement and include walking, running, jumping, and skipping. Postural skills involve both stationary balance such as sitting and standing posture and moving balance such as climbing stairs or stepping over obstacles. 

Object interaction skills involve movements with an object such as throwing, catching, and kicking a ball, carrying something while walking, and doing the monkey bars.

What Are the Six Motor Milestones of a Child?

1. Crawling
2. Walking and Running
3. Walking Up and Down Stairs
4. Jumping
5. Skipping and Galloping
6. Throwing and Catching

What Are the Physical Motor Development Milestones?

Here are some physical motor development milestones to watch for as your child grows. You will notice there is always a wide range as it is very normal for children to have some variance in these skill development timelines!

0-3 months

• Bringing both hands to the mouth
• Rotating head left to right
• Lifting head when on tummy

3-6 months

• Bringing feet to the mouth
• Pushing through palms with straight arms when on tummy
• Rolling

6-9 months

• Sitting independently
• Rolling tummy to back and back to tummy
• Pushes up on hands and knees from tummy

9-12 months

• Pulling to stand on objects
• Crawling on hands and knees
• Standing independently for a few seconds

12-18 months

• Walking independently

2 years

• Kicking a ball
• Rolling or tossing a ball
• Goes upstairs with help

5 years

• Mature running pattern
• Balance on one leg for 10 seconds
• Goes up and down stairs while alternating feet

How Do You Teach Pediatric Milestones?

Paediatric physiotherapists can help teach pediatric milestones through play including obstacle courses, positioning strategies and targeted skill practice with a focus on making things fun while building strength and endurance. It’s not just about learning the movement, it’s about symmetry and the quality of the movement as well! 

A pediatric physiotherapist can help to make sure that your child can hop evenly on both feet, crawl on both hands and knees, and can walk up and down the stairs alternating their legs, and many other skills that are important for participation in everyday life activities.

What Are the Three Principles of Motor Learning?

The 3 principles of motor learning are acquisition, retention, and transfer. To best explain these, we’ll use the example of learning how to jump.

• Acquisition is learning a new skill. For jumping, this could look like breaking the movement down into its different pieces like bending and straightening the knees, swinging the arms for momentum, clearing the ground, and landing safely. It could mean physically assisting the movement or using tools and structures like a trampoline to help learn the movement.
• Retention is the ability to remember the skill. The key to retention is repetition. Once a child has acquired the skill, repetition of the movement helps build those motor patterns. To use our example, retention would mean that your child is jumping by bending and straightening their knees, using appropriate arm swinging for momentum, and clearing the ground consistently.
• Transfer is the ability to apply the skill to activities at school, home, and in the community like skipping rope, jumping into a swimming pool, or jumping over a puddle.

Final Thoughts

When it comes to motor milestones in children, keep in mind that it is normal to see variability from child to child! If you are wondering if your child is on the right track, if you have questions about motor milestones in children, or want some help facilitating the development of these skills, book in today for a discovery call with myself HERE.

REFERENCES:

Newell, K. M. (2020). What are Fundamental Motor Skills and What is Fundamental About Them?, Journal of Motor Learning and Development, 8(2), 280-314. Retrieved Mar 20, 2023, from https://doi.org/10.1123/jmld.2020-0013

Kinactive Kids https://www.physio-pedia.com/Motor_Learning_-_Back_to_the_Basics

Written by Dr. Claire Wells, Chiropractor

 

Are you having pain during or after running? Whether you’ve been racing for years or just bought your first pair of running shoes, none of us are immune to pain and injury. Here are answers to some common questions you may be experiencing.

What Is the Most Common Running Injury?

Knee pain is the most common complaint, with hip pain coming in second. Common injuries include patellofemoral pain syndrome, iliotibial band syndrome, Achilles tendinopathy, medial tibial stress syndrome, tibialis posterior tendinopathy, plantar fasciopathy, and calf and hamstring muscle strains. Certain types of tissue are more prone to injury depending on variables like distance and speed, the total volume of training, and experience level in the sport.

What Causes Running Injuries?

It is usually impossible to pinpoint one specific factor that is to blame when you get injured. Here are some things to keep in mind based on the research in this area:

• The NUMBER ONE risk factor for future injuries is a previous injury. This is why it is important to fully rehabilitate all injuries, no matter how severe. Being pain-free does not mean that the tissue is fully healed or that strength and function are restored.
• Training errors can also play a huge role. 80% of running injuries are overuse injuries. Training volume (frequency, duration, and distance) and training intensity (how hard you’re working) are often poorly managed.
• Shoe type does not predictably contribute to injury risk.
• Gait biomechanics can play a role. Every run requires thousands to tens of thousands of steps, so the way you move with each step matters. Believe it or not, running is a skill!
• Many non-sport factors play a role in how ready your body is to handle the stress of training, and in how sensitive your body is to pain. These include sleep, nutrition, hydration, mental health, emotional state, overall physical health, and life stressors.

How Do You Tell If A Running Injury Is Serious?

Here are some indications that you should get assessed:

• Pain exceeds 3/10 (with 10/10 representing the worst pain you can imagine)
• You notice swelling, redness, or another visible change in the pain location.
• There was a sudden onset of pain with a clear mechanism of injury (ex: you rolled your ankle, or you felt/heard a “pop” when your knee twisted, etc.)
• It used to hurt only at the start of runs, but now it hurts the whole time, worsens during your run, or starts to linger after you stop.
• It does not improve with a few days off training.
• You have tried stretching, foam rolling, medication, ice/heat, etc. and it’s persisting or worsening.
• You have tingling, pins and needles, numbness, sharp shooting pain, and/or electric-like pain.

How Long Does a Running Injury Take to Heal?

It depends on things like the extent and duration of the injury, the type of tissue that is injured, and whether you are appropriately modifying what you’re doing. Here are some general timelines for tissue healing in an otherwise healthy body:

• Muscle: 2 weeks to 12 months (depending on severity)
• Tendon: 2 weeks to 12+ months (depending on severity)
• Bone: 6-12 weeks
• Ligament: 2 weeks to 12 months (depending on severity)
• Cartilage: 9+ months

It is important to keep in mind that these are timelines for tissue healing, not for return to sport at full capacity. Returning to running needs to be gradual and progressive but may take place before the tissue is completely healed.

What Is the Fastest Way To Heal a Running Injury?

Most injuries can be managed by modifying the variables of your training program and doing specific rehabilitative exercises. However, the specifics drastically vary based on the injury and the individual. For example, some injuries require total rest from weight-bearing on the injured leg, while some require heavy loading of the painful tissue, so it’s important to get assessed by a professional. 

Often, we can help manage symptoms with manual therapy (such as soft tissue treatment and joint mobilizations) and therapeutic modalities (such as acupuncture or dry needling, and Shockwave Therapy in Calgary South) to help get you back running as soon as possible.

Is Walking Good For Running Injuries?

Walking may be appropriate depending on the injury and whether walking recreates the pain that you have when you run. The problem with walking is that it doesn’t replicate the exercise intensity of running, so cross-training may be better if you want to maintain fitness. This could include cycling, cross-country skiing, or using an elliptical – whatever you have access to that doesn’t aggravate your pain. 

Again, it depends a lot on the injury you have, so it’s best to consult with your Chiropractor or physiotherapist. Once you are cleared to return to running, using walking in a run-walk progression is a helpful strategy that is supported by research.

When Can I Start Running Again After an Injury?

There are different approaches to this, but a good general rule would be that you need to be pain-free with walking and cross-training for 2+ weeks first and be able to perform basic single-leg strength and plyometric exercises with proper form and no pain. Some examples include:

• 30 seconds of single-leg squats at a rate that mimics your running cadence
• 20+ reps of single-leg calf raises
• 1 minute of double-leg hops; equal distance on both sides for a single-leg triple-hop test

The best thing to do would be to get assessed by a chiropractor or physiotherapist who can test for symmetrical and sufficient ranges of motion, balance, and strength. And be sure to follow a structured, gradual, and symptom-monitored return to running program when you do get back to it!

How Do Physiotherapists and Chiropractors Help Treat Running Injuries?

Both can help by assessing your injury, testing for movement dysfunction and strength imbalances, identifying training factors that may have contributed to your injury, and guiding you through the recovery process. They can make a plan to get you better based on your injury – including education, training modifications, specific exercises, and hands-on treatment.

At Peak Health And Performance, we offer a wide range of treatment options including Physiotherapy, Massage Therapy, Chiropractic Care and Concussion Care to address a variety of conditions and help improve your quality of life. Book your appointment today!

Some of the common conditions we can help with include:

• Sports injuries
• Musculoskeletal injuries
• Neck pain
• Shoulder pain

Written by Kate Thompson, Physiotherapist 

 

Many diagnoses and conditions are prescribed medication to help manage it. Diabetes is treated with insulin or high cholesterol with some variety of statin medication. For OA, one of the best-known treatment options is exercise, when dosed correctly and specific to you.

How Exercise Can Help Manage Your Osteoarthritis Symptoms

Ongoing research suggests that exercise can promote change both directly, at the joint, and indirectly, by improving your overall function and movement quality [1]. Osteoarthritis commonly involves the breakdown of the joint, inflammation, and decreased cell metabolism or turnover.

Studies show that exercise may have a protective effect on the joint by stimulating a process called ‘autophagy’, which recycles old and/or damaged cells into newer, healthier ones! [1] This is an amazing process that the body goes through that essentially goes out with the old, and in with the new.

Exercise can promote positive change indirectly as well, by improving stability and function by increasing muscle strength and helping you move in a way that distributes the load of your body more efficiently. One of the most well-known research programs studying the effect of exercise on individuals living with hip and knee osteoarthritis is called Good Life with osteoArthritis in Denmark (GLA:D). 

This consists of 2 weeks of education and 6 weeks of neuromuscular training led by a physiotherapist. In one GLA:D study with nearly 10,000 participants, pain intensity and quality of life improved significantly following the completion of the program! Furthermore, participants who completed the program reported they took fewer painkillers and took fewer sick days [2].

Introducing Peak Arthritis: A Physiotherapy Program for Osteoarthritis

The Peak Osteoarthritis Intervention Program is an 8-week exercise program that is based on GLA:D research and combines education and neuromuscular training to help individuals living with OA manage their symptoms and continue to participate in the activities they enjoy.

Participants will be assessed by a physiotherapist and be provided with a plan specific to them, and be guided through an 8-week exercise program at 2x 1-hr sessions/week. Sessions are structured as circuit training, where participants learn the fundamentals of strength training in a way that is of special benefit to Osteoarthritic joints. 

You start by learning the fundamentals of how to hinge, squat and lunge and then we progressively load these movements, based on your ability levels. You will have 1:1 sessions with a physiotherapist throughout your program, and have access to group exercise facilities to perform your exercises.

What Are the Goals of the Program?

The ultimate goal of the program is to help you be able to do more of the things you love in life. We want to help you feel fulfilled and happy. Whether that is being able to feel like you can go up and down the stairs without clinging on to a railing, being able to walk 3 blocks instead of 1, getting back into an exercise routine, playing tennis, getting back into golf, whatever your WHY is! Let our Peak Health physio know what your goals are at the beginning of the program and you can set realistic expectations together for what you hope to achieve from the program.

 

Short-term goals for how to help you achieve your longer-term goal are as follows:

• Get stronger
• Move smarter
• Gain confidence (In the way you move, in your ability to complete daily tasks, in your knowledge about what OA is and how it affects your body)

How Do I Know if I Would Be a Good Fit for the Program?

There is no specific age requirement for participation in this program! We welcome beginner to experienced exercisers and most levels of OA patients (mild OA to severe OA). Regardless of your experience with exercise, we will adapt the program to your unique ability level. 

You may not be a good fit for the program if you are unable to stand or walk independently without a higher-level gait aid such as a walker. If you would like more information to know if you would be a good fit for the program, please call the clinic at 403-287-7325 and you can request that the lead physiotherapist for the program call you with more information.

We can’t WAIT to see how exercise rehabilitation can help you move better!

Book a discovery call with our physiotherapist Kate today HERE.

At Peak Health And Performance, we offer a wide range of treatment options including massage therapy and concussion care to address a variety of conditions and help improve your quality of life. Some of the common conditions we can help with include:

• Poor posture
• Connective tissue issues
• Knee injuries and Knee pain
• Joint pain relief
• Impaired range of motion

References:

1. Kong H, Wang XQ, Zhang XA. Exercise for Osteoarthritis: A Literature Review of Pathology and Mechanism. Front Aging Neurosci. 2022 May 3;14:854026. doi: 10.3389/fnagi.2022.854026. PMID: 35592699; PMCID: PMC9110817.
2. Skou ST, Roos EM. Good Life with osteoArthritis in Denmark (GLA:D™): evidence-based education and supervised neuromuscular exercise delivered by certified physiotherapists nationwide. BMC Musculoskelet Disord. 2017 Feb 7;18(1):72. doi: 10.1186/s12891-017-1439-y. PMID: 28173795; PMCID: PMC5297181.

Written by Kate Thompson, Physiotherapist

 

What Are Some Common Myths About Osteoarthritis?

Although a very common diagnosis, there seem to be many misconceptions about what Osteoarthritis is or what may affect it. Let’s dive into some of these together! 

Myth #1: I Heard That Running Gives You OA

 “I enjoy running for exercise. I don’t think I have Osteoarthritis, but I have heard that continuing to run long distances can put me at risk for developing Osteoarthritis.”

What the research says: Research has shown that both non-runners and runners exposed to high-volume training loads (>92 km/week) have higher rates of Osteoarthritis than recreational runners [1]. Therefore, due to the numerous other health benefits of running, it is not sound advice to tell recreational runners to stop running [1,2].

It is important to consider that these studies do not account for other risk factors of Osteoarthritis, such as age, previous trauma and obesity, which may have had an effect on the results of these studies. 

Myth #2: Running Will Worsen My OA.

 “I have Osteoarthritis and have been told that I should stop running, as it will make my Osteoarthritis worse.”

What the research says: There have been a variety of studies that have found that running does not appear to accelerate the progression of existing knee OA in runners >50 years of age [1]. There have however been some small-scale studies that have suggested that individuals with OA who run may require increased recovery time from running [1]. 

Therefore, it is recommended that if an individual has OA, enjoys running, and is managing their symptoms well, they should continue to run as long as they monitor running frequency to ensure adequate recovery time between bouts [1]. For example, if you run 3 days/week, I would recommend spreading the runs out throughout the week instead of running 3 days consecutively.

Myth #3: I Have OA so I Can’t Do Anything Fun Anymore.

 “I have been diagnosed with Osteoarthritis and have been told to stick to ‘low-impact’ activities. I want to continue to play hockey for as long as I can but I am nervous that it will make my OA worse.”

What the research says: There have been multiple studies to suggest that long-term participation in high-impact activities are not associated with the development of OA [2,3]. That being said, these studies are limited, as it is challenging to control for other risk factors of Osteoarthritis. Thus, it may be more productive to make these decisions based on your current symptoms. 

For example, if you experience a mild increase in pain while playing hockey, however, the pain returns to your baseline by the next day, it is likely safe for you to continue playing. On the contrary, if playing hockey increases your pain significantly after playing and takes 2-3 days to return to baseline levels, I would recommend discontinuing until you have a thorough assessment from a physiotherapist in Calgary. 

The physiotherapist will be able to tell you if playing hockey is a realistic goal, and if it is, they can help you make activity modifications and provide you with exercises to help you return to hockey with fewer symptoms! If it is not a realistic goal for you, they will help you find other ways to stay active in a way that fits with your lifestyle and your goals. 

Myth #4: I Have OA in My Back so I Can’t Twist.

“I have Osteoarthritis in my spine. I was told I should avoid bending forward or twisting.”

What the research says: What you do with your spine is not as important as how you do it. Your spine is made to twist and bend, however, over time some of these movements can become stiff and painful. 

Gentle mobility exercises and performing movements that load your spine such as squats, hinges, pushes and pulls can make your spine more resilient and allow you to complete your daily activities with less irritation and risk of injury.

Myth #5: There Is a One Size Fits All Plan for OA

“I heard that there is one specific exercise program that you can do that will help you manage Osteoarthritis symptoms.”

What the research says: Exercise is a leading treatment approach for Osteoarthritis, however, there is no ‘one size fits all’ formula to exercising with Osteoarthritis [4]. A great place to start is learning how to squat, hinge, lunge, push and pull with good technique, as these are movements that occur naturally throughout the day as you complete daily activities. 

For example, you have to squat to sit on a chair, lunge to get up the stairs, and hinge to unload your dishwasher. Factors such as the weight you lift, distance you move, and sets/reps you complete should vary based on your symptoms and fitness level.

In summary, every individual is unique and your presentation requires a specific exercise and management plan designed for you. Contact Peak today to see if you would be a good candidate for a physiotherapy assessment and personalized exercise rehabilitation plan to help manage your OA. Click HERE to book your discovery call today. 

At Peak Health And Performance, we offer a wide range of treatment options including massage therapy and concussion care to address a variety of conditions and help improve your quality of life. Some of the common conditions we can help with include:

• Poor posture
• Connective tissue issues
• Knee injuries and Knee pain
• Joint pain relief
• Impaired range of motion

 

References:

1. Alexander JLN, Willy RW, Culvenor AG, et al. Infographic. Running Myth: recreational running causes knee osteoarthritis. British Journal of Sports Medicine 2022;56:357-358.
2. Horga LM, Henckel J, Fotiadou A, et al 3.0 T MRI findings of 104 hips of asymptomatic adults: from non-runners to ultra-distance runners. BMJ Open Sport & Exercise Medicine 2021;7:e000997. doi: 10.1136/bmjsem-2020-000997
3. Chang AH, Lee J, Chmiel JS, Almagor O, Song J, Sharma L. Association of Long-term Strenuous Physical Activity and Extensive Sitting With Incident Radiographic Knee Osteoarthritis. JAMA Netw Open. 2020;3(5):e204049. doi:10.1001/jamanetworkopen.2020.4049
4. Kong H, Wang XQ, Zhang XA. Exercise for Osteoarthritis: A Literature Review of Pathology and Mechanism. Front Aging Neurosci. 2022 May 3;14:854026. doi: 10.3389/fnagi.2022.854026. PMID: 35592699; PMCID: PMC9110817.

Written by Kate Thompson, Physiotherapist 

So You’ve Been Told You Have Osteoarthritis. You’ve Landed on The Right Page…

What Is Osteoarthritis?

Osteoarthritis (OA) is a disease that commonly affects joints of the body such as the hip and knee, shoulders and hands [1], and is a lot more common than people think. If we zoom into what is going on at the joint, it helps paint a picture of what is actually going on when an individual develops OA.

A joint is where two bones come together, and serve the function of absorbing and distributing mechanical load in your body [1]. A healthy joint should have cartilage covering the surface of the bones, enough space between the bones so they do not rub against each other, as well as ligaments and muscles surrounding them to support them and keep them stable.

OA results in changes to the cartilage, bone and joint space, and can also affect the surrounding ligaments, tendons and muscles [1]. As a result, the structure and function of the joint change which can result in symptoms such as pain, stiffness and instability [1].

 

 

“If you have knee osteoarthritis, you may feel unsteady when putting all of your weight through one leg while going down the stairs. This is because the muscles, ligaments, and joint structure are not able to support and disperse the weight of your body as it normally should.”

 

Who Is at Risk of Developing OA?

Known risk factors for developing OA include [1]:

• Aging
• Obesity
• Genetics
• Previous trauma/injury to the area
• Gender (females have a higher incidence than males)
• Hormones and metabolic disease

It is important to note, however, that OA is not inevitable if you have one of these risk factors! For example, although aging increases your risk of developing OA, not everyone who ages develops OA [1].

My Doctor Diagnosed Me With Osteoarthritis, but I Have Never Had an X-Ray. Do I Need One To Confirm the Diagnosis?

This is a tricky subject. In the past, it was common practice for health practitioners to refer patients for X-rays to guide the diagnosis of musculoskeletal conditions. Newer research, however, has identified that there may not always be a strong correlation between imaging findings and patient symptoms [2,3]. 

For example, if you took 100 people off the street and took an X-ray of their knees, some people without any knee pain at all may have X-rays that indicate OA, and some people with severe, debilitating knee pain may have X-ray results showing a healthy joint. In addition, if you are an older adult, it is common for there to be structural abnormalities found on your imaging that simply have developed over time and are not related to your symptoms at all [2].

Therefore, recent recommendations advise that OA should be diagnosed based on your symptoms, instead of through X-ray.

For example, if your symptoms follow a typical presentation of OA, such as joint pain, stiffness in the morning lasting <30 mins, crepitus with movement and weakness/instability, it is acceptable to be diagnosed without a referral for an X-ray [2,3]. 

Your doctor may request an X-ray if you have an atypical presentation and/or if there is suspicion of a different diagnosis2. Examples of an atypical presentation may include severe local inflammation, redness around the joint and rapid, progressive pain that is unrelated to use [2].

How Do I Know When I Need Surgery?

A better question might be, “How do I know if I need surgery?”. It’s important to consider that not everyone diagnosed with OA requires a joint replacement! It is recommended that patients diagnosed with OA try conservative management for a significant period of time to manage their symptoms, improve function and delay further changes to the joint structure [4]. 

The Osteoarthritis Research Society International suggests that NSAIDs (non-steroidal anti-inflammatory drugs) and exercise have the highest level of evidence for improving knee and hip OA symptoms [4]. If you have spent a significant amount of time trying conservative methods and still are unable to manage your pain, and your pain is considerably impacting your quality of life, it may be time to have a conversation with your doctor about other options.

Although there is significant evidence demonstrating that joint replacement surgery can improve symptoms, function and quality of life, surgical candidates are often under-educated about the risks of surgery and what the recovery process might look like [5]. For example, it can take months of physiotherapy to restore your mobility and strength following surgery. 

Furthermore, you may still experience pain in the months following surgery as you progress through rehab to optimize your new joint function. In addition, there is a risk that you may not regain a full range of motion following surgery [5]. 

It is important to remember that everyone has a unique anatomy, fitness level, stress level, and life experiences going into surgery and all of these factors will play a role in your recovery. If you are currently waiting for surgery, it is important to consult with a Peak Health physiotherapist on how you can best prepare for the surgery to optimize your outcomes after the operation.

To learn more about Osteoarthritis, check out our other blogs on the topic or reach out to me directly at [email protected]! I would be more than happy to answer any questions you may have on how physiotherapy and exercise rehabilitation can help you manage your OA diagnosis.

To book a free discovery call with me, click here.

At Peak Health And Performance, we offer a wide range of treatment options including massage therapy to address a variety of conditions and help you get back to your daily activities pain-free. Some of the common conditions we can help with include:

• Poor posture
• Connective tissue issues
• Knee injuries
• Joint pain relief

References:

1. He Y, Li Z, Alexander PG, Ocasio-Nieves BD, Yocum L, Lin H, Tuan RS. Pathogenesis of Osteoarthritis: Risk Factors, Regulatory Pathways in Chondrocytes, and Experimental Models. Biology. 2020; 9(8):194. https://doi.org/10.3390/biology9080194
2. Xia Wang, Win Min Oo, James M Linklater, What is the role of imaging in the clinical diagnosis of osteoarthritis and disease management?, Rheumatology, Volume 57, Issue suppl_4, May 2018, Pages iv51–iv60, https://doi.org/10.1093/rheumatology/kex501
3. Wood G, Neilson J, Cottrell E, Hoole S P. Osteoarthritis in people over 16: diagnosis and management—updated summary of NICE guidance BMJ 2023; 380 :p24 doi:10.1136/bmj.p24
4. Bannuru RR, Osani MC, Vaysbrot EE, Arden NK, Bennell K, Bierma-Zeinstra SMA, Kraus VB, Lohmander LS, Abbott JH, Bhandari M, Blanco FJ, Espinosa R, Haugen IK, Lin J, Mandl LA, Moilanen E, Nakamura N, Snyder-Mackler L, Trojian T, Underwood M, McAlindon TE. OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis. Osteoarthritis Cartilage. 2019 Nov;27(11):1578-1589. doi: 10.1016/j.joca.2019.06.011. Epub 2019 Jul 3. PMID: 31278997.
5. Beswick AD, Wylde V, Gooberman-Hill R, Blom A, Dieppe P. What proportion of patients report long-term pain after total hip or knee replacement for osteoarthritis? A systematic review of prospective studies in unselected patients. BMJ Open. 2012 Feb 22;2(1):e000435. doi: 10.1136/bmjopen-2011-000435. PMID: 22357571; PMCID: PMC3289991.