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Brain food. Physical activity and neurological diseases… what are the connections?

Despite decades of research demonstrating clear benefit, physical activity has received little interest from physicians in the prevention and treatment of neurological disease, including stroke, Parkinson’s, dementia, and mood disorders.

Physically active men and women have a 25 to 30 percent reduced risk of stroke when compared with those who are inactive. After a stroke, greater aerobic fitness, muscle strength, and physical endurance improves functional abilities such as walking as well as improved self-confidence and general well being.

Physical activity is critical to the well-being of Parkinson’s patients and should be introduced in the early stages of the disease. No adverse events related to exercise exposure in people with Parkinson’s disease have occurred in the various published controlled studies.

Photo by NCVO. Used with permission. All rights reserved. Source: flickr

Photo by NCVO. Used with permission. All rights reserved. Source: flickr

Numerous published studies have demonstrated that regular physical activity benefits patients with MS and strong evidence exists of improvements in muscle function, aerobic fitness, quality of life, and mobility.

Mild cognitive impairment is a clinical entity characterized by cognitive decline greater than expected for an individual’s age and education level but does not interfere notably with everyday function. Dementia is a broad descriptive term that encompasses a number of slowly progressive degenerative conditions. Exercise has cognitive benefits for older adults with mild cognitive impairment.

Does physical activity benefit cognitive function in people with dementia? The evidence is still insufficient. Nevertheless, older people with dementia still have the same need for physical activity as other seniors with an array of benefits from improved depression, fewer behavioral disturbances, and a positive effect on mobility.

Depression has a lifetime prevalence of between six and twenty percent worldwide, with the rate of depression increasing over the past 50 years. The WHO ranks depressive disorders as the fourth largest health problem in the world. More than 100 cohort studies over many decades demonstrate that regular physical activity is effective in reducing the onset of depression.

The findings of RCTs show that exercises reduces the number and severity of symptoms of depression in both depressed and non-depressed adults. The magnitude of the effect is generally about 40 to 50 percent greater than placebo or non-pharmacological treatments.

The ACSM physical activity guidelines of approximately 150 minutes per week of aerobic activity and one to two sessions of strength-based training are an appropriate foundation for clients with the conditions above. Paul McCrory and Teresa Liu-Ambrose discuss in greater detail the above and other illnesses and provide numerous references in Chapter 54, “Exercise to treat neurological diseases and improve mental health,” of Clinical Sports Medicine.

For more information on exercise prescriptions for over 60 medical conditions download a free copy of the Swedish National Institutes of Public Health, Physical Activity in the Prevention and Treatment of Disease (



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Pre-exercise stretching – is it useful? ~ Ian Shrier MD, PhD, Dip Sport Med, FACSM

Two recently published meta-analyses on the effects of pre-exercise stretching have received media attention.[1,2] In general, these studies arrived at the same conclusions as previous reviews: pre-exercise stretching reduces tests of performance (e.g. strength, power). This effect is minimal with stretches of very short durations and increases the longer the stretch is held.[3] Although I have promoted similar conclusions in the past,[4] clinicians should understand when it is appropriate to generalize these results to their patients and athletes, and when it is not.

First, the results refer to pre-exercise stretching. Stretching regularly over weeks to months increases tests of performance.[4] The current results should not be applied to yoga or other forms of regular stretching.

Second, the studies measured tests of performance, not performance.[5] Stretching before karate may allow one to kick higher. If stretching allows an athlete to hit the opponent in the head where this would not be possible without stretching, then stretching improves performance because hitting the opponent with a decreased force is better than not hitting the opponent at all!

Photo by VanDerMouche. Used with permission. All rights reserved. Source: flickr
Photo by VanDerMouche. Used with permission. All rights reserved. Source: flickr

Third, the original studies were conducted in healthy individuals. The effects of stretching in injured patients remain to be determined. Although stretching weakens healthy muscle, stretching also acts as an analgesic.[6] Because pain from injured tissue causes muscle inhibition, reducing pain through stretching may or may not increase strength in this context.

Fourth, with regards to injury risk (not covered by these meta-analyses), other reviews have suggested that pre-exercise stretching does not reduce overall injury risk.[6] Some authors have suggested pre-exercise stretching may reduce tendon injuries.[7] However, if tendon injuries are reduced but total injuries remain the same, there must be an increase in other types of injuries (e.g. increased falls through decreased proprioception). In addition, similar to performance tests, some evidence suggests regular stretching might be beneficial even though pre-exercise stretching is not.[6]

Fifth, research on the effect of stretching in injury rehabilitation is scarce. When stretching was compared to strengthening for rehabilitation, the strengthening group does much better.[8,9] To my knowledge, the potential benefit of adding stretching to strengthening in rehabilitation has not been evaluated.

Finally, different authors define the recently introduced term “dynamic stretching” differently. Generally, it refers to slow movements through a normal range of motion. Such activity does not increase range of motion [10,11] and should be considered as a method to increase muscle metabolic activity and temperature rather than a “stretch” per se. Therefore, the comparison group for such studies should be other forms of muscle activity and not types of stretching.

In summary, I agree with the authors’ conclusions. Future research should focus on areas that remain underdeveloped, including the effect of pre-exercise stretching for high impact sports and when a patient is injured, as well as the effects of regular stretching (after exercise, outside periods of exercise) on injury.

For a detailed look at stretching turn to Chapter 15, Principles of rehabilitation, in Clinical Sports Medicine.

Dr. Ian Shrier has been practicing sport medicine physician for over 25 years, with doctoral training in physiology and post-doctoral training in epidemiology. He has over 150 peer-reviewed publications on exercise, sport medicine injuries, and methodological research, and is an editorial board member of four international sport medicine journals


1.         Simic L, Sarabon N, Markovic G. Does pre-exercise static stretching inhibit maximal muscular performance? A meta-analytical review. Scand J Med Sci Sports 2013;23(2):131-48.

2.         Gergley JC. Acute effect of passive static stretching on lower-body strength in moderately trained men. J Strength Cond Res 2013;27(4):973-7.

3.         Kay AD, Blazevich AJ. Effect of acute static stretch on maximal muscle performance: a systematic review. Med Sci Sports Exerc 2012;44(1):154-64.

4.         Shrier I. Does stretching improve performance: A systematic and critical review of the literature. Clin J Sport Med 2004;14:267-273.

5.         Shrier I. When and who to stretch. Gauging the benefits and drawbacks for individual patients. Phys Sportsmed 2005;33(3):22-26.

6.         Shrier I. Does stretching help prevent injuries? In: MacAuley D, Best T, editors. Evidence-based sports medicine. London: BMJ Publishing Group, 2007.

7.         Witvrouw E, Mahieu N, Roosen P et al. The role of stretching in tendon injuries. Br J Sports Med 2007;41(4):224-6.

8.         Holmich P, Uhrskou P, Ulnits L et al. Active physical training for long-standing adductor-related groin pain. Lancet 1999;353:439-443.

9.         Svernlov B, Adolfsson L. Non-operative treatment regime including eccentric training for lateral humeral epicondylalgia. Scand J Med Sci Sports 2001;11(6):328-334.

10.       Curry BS, Chengkalath D, Crouch GJ et al. Acute effects of dynamic stretching, static stretching, and light aerobic activity on muscular performance in women. J Strength Cond Res 2009;23(6):1811-9.

11.       O’Sullivan K, Murray E, Sainsbury D. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects. BMC Musculoskelet Disord 2009;10:37.

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Barefoot and minimalist: are they equivalent? ~ Jason Bonacci, PhD

Musculoskeletal overuse injury is highly prevalent in distance runners[1, 2].  The management of these overuse injuries often includes training advice, footwear prescription and running technique analysis.  Footwear prescription is an important component of the rehabilitation program as shoes can alter muscle activity and the kinematics and kinetics of the lower limb during running[3, 4], thereby influencing loading experienced with each foot strike.

Photo by Chris Hunkeler. Used with permission. All rights reserved. Source: flickr

Photo by Chris Hunkeler. Used with permission. All rights reserved. Source: flickr

Clinicians often prescribe footwear on the basis of foot type and categories provided by shoe manufacturers; such as “cushioning” and “motion control”. More recently, shoe manufactures have developed a new category of footwear termed “minimalist”. The idea is that these shoes provide the least interference to the natural running pattern as possible, whilst still providing foot protection. Manufacturers claim these minimalist designs provide the “benefits of training barefoot” or promote “barefoot running form.”

Despite the claims it is not known if these minimalist shoes can replicate the natural running pattern that occurs when running barefoot. Putting aside the argument of which is best (barefoot v shod), the clinician has very little evidence-based information upon which to form a basis for prescription of these shoes. Our recent study tested the hypothesis that running in a minimalist shoe is similar to running barefoot[5].

We undertook a three-dimensional overground running analysis of 22 highly trained runners in four different conditions:

  • their normal running shoes;
  • barefoot;
  • racing flats; and
  • minimalist shoes (Nike Free 3.0).

The participants performed ten running trials in each condition at a velocity of 4.48 m/s along an indoor synthetic running track. Our results revealed that the dynamics of running in a minimalist shoe were more similar to that of the other test shoes than running barefoot. In other words, the notion that running in a minimalist shoe is similar to running barefoot was not supported by the results of our study.

Running barefoot resulted in a flatter foot placement at foot strike, smaller knee flexion angles at midstance, lesser joint moments and work done at the knee and greater joint moments and work done at the ankle. These variables were different to all shod conditions, but similar between shod conditions, suggesting that the minimalist shoe acted more like a shoe than a barefoot condition.

When running barefoot there was a 24 percent decrease in negative work done at the knee and 19 percent increase in positive work done at the ankle in comparison to shod running. Clinicians should consider the potential therapeutic and performance implications of these loading changes if prescribing barefoot running for their athletes.

We readily acknowledge that there are minimalist shoes that are much more minimal than the Nike Free utilised in our study.  The Nike Free has an elevated heel and considerable cushioning which is not present in all minimalist shoes. However, this shoe clearly sits in the market as a minimalist shoe and is sold in very high volume (accounts for over 50 percent of sales in the minimalist category in Australia).

A more recent study[6] compared the lower limb running mechanics when running barefoot and in a more minimalist shoe (Vibram Fivefingers) than the Nike Free. That study found greater similarities between barefoot and minimalist shoe running, however there were still differences between the conditions. Specifically, ankle dorsiflexion kinematics and peak ankle plantarflexion moments and power were different between the minimalist shoe and barefoot running.

While this area of research is rapidly growing and we can expect to read more in this space, the evidence to date suggests that minimalist shoes cannot entirely replicate the dynamics of running barefoot. There are greater similarities between running barefoot and running in a minimalist shoe if that shoe is without cushioning and an elevated heel, but the idea that a shoe condition is the same as barefoot is not justified just yet.

Jason Bonacci holds an academic appointment in Anatomy and Biomechanics in the School of Exercise and Nutrition Sciences, Deakin University. He is also at Physiotherapist at Olympic Park Sports Medicine Centre in Geelong, Australia.


1 van Gent RN, Siem D, van Middelkoop M, et al. Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review Br J Sports Med 2007;41:469-80.

2 Van Mechelen W. Running injuries – a review of the epidemiologic literature. Sports Med 1992;14:320-35.

3 Kerrigan C, Franz JR, Keenan G, et al. The effect of running shoes on lower extremity joint torques. Phys Med Rehabil 2009;1:1058-63.

4 Nigg B. Biomechanical considerations on barefoot movement and barefoot shoe concepts. Footwear Sci 2009;1:73-9.

5 Bonacci J, Saunders PU, Hicks A, et al. Running in a minimalist and lightweight shoe is not the same as running barefoot: a biomechanical study. Br J Sports Med 2013;47:387-92.

6 Paquette MR, Zhang S, Baumgartner L. Acute effects of brefoot, mnimal shoes and running shoes on lower limb mechanics in rear and forefoot strike runners. Footwear Sci 2013;5:9-18.



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The athlete with shoulder pain: how to move from a diagnostic dilemma, and a therapeutic drama, to an exciting challenge? ~ Babette Pluim, MD, PhD, MPH

Shoulder injuries in overhead athletes can be very challenging for even the most experienced clinicians. I have worked in tennis for the last 22 years and I know that no two shoulder injuries are quite the same and no shoulder injury is ever entirely easy! My initial gut reaction would be “oh, oh, here we go again” because tennis players, like all elite athletes, want to continue playing and a quick, shoulder fix, seldom works in an overhead athlete.

If you are very lucky, a few days of rest might be sufficient, but more often than not, the injury will not resolve without weeks of careful rehab. The athlete will become steadily more desperate, and your confidence will start to waver. Thankfully, the days of reckless NSAIDs use and steroid injections are long past and we now have a better understanding of the underlying pathology (SLAP, GIRD and scapular dyskinesia) and how to manage these entities in an evidence-based way.

Photo by emmett.hume. Used with permission. All rights reserved. Source: flickr

Photo by emmett.hume. Used with permission. All rights reserved. Source: flickr

But where do you start, what do you do, when do you do it and how do you manage your athlete’s expectations? The playing field has changed enormous in recent years and the general medical textbooks cannot possibly keep up with the latest advances in shoulder injury management.

This is where the book (so much more than just a book!) comes in –Clinical Sports Medicine. I was very fortunate to have been invited to co-author Chapter 21 on Shoulder Pain with Dr. Ben Kibler and Prof. George Murrell and researching the chapter with these experts has been a revelation. I know that I am a better clinician as a result and I’m sure that the book can help you to better manage your athletes and resolve their injuries.

The chapter starts off with six entities, each of which can be responsible for shoulder discomfort – the rotator cuff, instability, labral injury, stiffness, AC joint pathology and referred pain. Each segment takes you through the classical clinical evaluation process – history, examination, and investigations (x-ray, ultrasound, MRI, arthrography and diagnostic arthroscopy) –and not only are all the shoulder tests explained in the text, you can actually watch a video of the tests being conducted by Dr Mark Hutchinson (via the dedicated CSM website, available to you when you buy the book).

For those of you who are not familiar with Mark’s work, he is the creator of the famous YouTube knee examination series which has achieved over 3.6 million downloads. This is followed by sections on the rare shoulder injuries, the principles of shoulder rehabilitation and a final section on “putting it all together”.

So you now have all the tools you need to boost your confidence and to put your athlete on the road to recovery. That sinking feeling you had every time the words ‘sore shoulder’ were mentioned has now been banished forever and ‘oh, oh’ has been replaced by a triumphant ‘aha’ – you are now a match for anything that an overhead athlete can throw at you!

Babette Pluim, MD, PhD, MPH, is a Sports and Exercise Physician and Deputy Editor of the BJSM. She is Chief Medical Adviser of the Dutch Tennis Federation and Team Physician of the Dutch Davis Cup and Fed Cup teams.


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@PeterBrukner discusses major headline: Successful antibiotic treatment in a subset of people with chronic low back pain

This post was originally published on the BJSM blog site. Used with permission. 

It is not often that something I read in the medical research literature gives me goosebumps and an incredible urge to tell everyone I know about it (thank god for Twitter!). I had that feeling today when, after an article in this morning’s Guardian newspaper, I read two recent papers published by a Danish group of researchers led by Hanne Albert in the European Spine Journal (links below).

Infection and low back pain!?

The papers relate to the possibility of an infective cause in a sub-group of patients with chronic low back pain. This sub-group is those patients with Modic changes. Modic changes (MC) are bone oedema in the adjoining vertebra to one in which there is a disc herniation. MC are present in 46% of patents with chronic low back pain compared to 6% in the general population. MC can only be reliably detected using MR imaging. A number of previous studies have demonstrated the presence of bacteria especially Propionbacterium acnes (P. acnes) in disc nucleus tissue evacuated at surgery from patients with lumbar disc herniation.

Photo by Andreanna Moya Photography. Used with permission. All rights reserved. Source: flickr

Photo by Andreanna Moya Photography. Used with permission. All rights reserved. Source: flickr

The first paper Does nuclear tissue infected with bacteria following disc herniations lead to Modic changes in the adjacent vertebrae? reports on 61 patients who had nuclear disc material removed while undergoing surgery for chronic low back pain. Microbiological cultures were positive in 28 (46%) patients, of which 26/28 were anaerobic cultures, 2 (3%) aerobic and 4 (7%) mixed. In the discs with a nucleus with anaerobic bacteria present, 80% developed MC in the vertebrae adjacent to the previous disc herniation, compared to none in the aerobic group and 44% with negative cultures. They concluded that the occurrence of MCs in the vertebrae adjacent to a previously herniated disc may be due to oedema surrounding an infected disc.

How do intervetebral discs become infected?

Organisms such as P. acnes are commonly found in hair follicles in the skin and in the oral cavity. They frequently invade the circulatory system during tooth brushing where they do not present an immediate risk because the blood stream is an aerobic environment. When an intervertebral disc is herniated, nuclear material extrudes into the spinal canal. Within a short time, neocapillarisation begins in and around the extruded nucleus material, inflammation occurs and brings with it macrophages. So far so good – no debate about any of that.

The innovation of the authors is their proposal that avascular and thus anaerobic disc provides an ideal environment for these anaerobic bacteria to flourish. In this setting, anaerobic bacteria that are normally inconsequential (low virulent) may enter the disc and give rise to a slowly developing infection.

Local inflammation in the adjacent bone (MC Type 1) may be a secondary effect due to cytokine production or microbial metabolites (e.g. propionic acid) entering the vertebrae through normal disc nutrition. P. acnes is known from the skin to trigger an adjacent inflammatory response. P. acnes cannot multiply in the highly vascular aerobic bone and are therefore not present where the MC occur.

All good in theory but what about an RCT?

The second paper is entitled Antibiotic treatment in patients with chronic low back pain and vertebral bone edema (Modic type 1 changes): a double-blind randomized clinical controlled trial of efficacy.  this paper reports the efficacy of antibiotic treatment in this group of patients with MC lesions and chronic low back pain. This double blind RCT study examined 162 patients with chronic low back pain (> 6 months duration) occurring after a previous disc herniation AND who had MC changes in the vertebrae adjacent to the previous herniation. Subjects were randomised to either 100 days of antibiotic treatment (Bioclavid) of two different dosages or placebo. Outcomes were evaluated at baseline, end of treatment and at 1 year follow up.

Primary outcomes were the well accepted disease-specific disability Roland Morris Questionnaire as well as the report of lumbar pain. The antibiotic group made highly statistically significant improvements on all outcome measures; the improvement continued from 100 days follow up until 1 year follow up. For example, on the disease specific disability, the antibiotic group was 15 at baseline, 11 at 100 days and 5.7 at 1 year compared to placebo (15, 14, 14). The report of lumbar pain decreased much more in the antibiotic group who started at a score of 6.7 and improved to scores of  5.0 (100 days) and 3.7 (1 year). The placebo group mean report of lumbar pain stayed constant at 6.3 from baseline through 100 days and 1 year (lower is better, of course).

Biologically plausible time course

Patients also reported that pain relief and improvement in disability commenced gradually, for most patients 6-8 weeks after the start of the antibiotic tablets and for some at the end of the treatment period. Improvements reportedly continued long after the end of the treatment period, at least for another 6 months, and some patients reported continuing improvement at 1-year follow up. The improvement seen in the antibiotic group at 1 year follow up was approximately twice that observed at the end of the 100 day treatment period, suggesting that a biological healing process that starts only when and after the bacteria have been killed.

Half the treatment group took one Bioclavid (amoxycillin-clavulanate 500mg/125mg) tablet three times a day while the other half took two tablets. The authors state that the long duration of antibiotic treatment is commonly prescribed for post-operative discitis. There was a trend towards an improvement with double dose, but did not reach significance.

What should we make of these papers?

This treatment is certainly an exciting possibility for one of the most difficult management challenges in medicine.  At this stage all the authors are saying is that in a particular sub-group of patients with chronic (>6 months) low back pain, those with Modic changes on MRI scan after lumbar disc herniation may respond well to long term antibiotic treatment. We are reluctant to prescribe long term antibiotics for reasons of potential development of resistance but there seems to be a rationale for long term use in this situation. Further studies need to assess the efficacy of shorter terms of treatment. Because this is the BJSM blog, we can point out to readers that the group’s pilot study was not accepted by a number of famous journals but saw the light of day via BJSM’s ‘peer-review fair review’ process. That paper came out in 2008.

I would think on the basis of this research it is reasonable to prescribe the recommended antibiotic program to those who strictly meet the clinical and MR imaging criteria. Especially if the only alternative seems to be surgery which has limited efficacy in these patients and is obviously vast more expensive than a course (albeit prolonged) of antibiotic therapy. Remember if you have this infection surgery will not be treating the cause.

It took the Nobel prize winning research  on Heliobacter and its relationship to stomach ulcers of West Australians Barry Marshall and Robin Warren to alert the skeptical medical community of the potential of infective causes of common conditions. Many investigators are currently seeking infective causes for a wide variety of common and uncommon medical disorders. This research will encourage such investigation. Undoubtedly we will find more causal infective relationships. Further work needs to be done to answer a range of questions (which antibiotic, what dose, how  long etc), but these two papers are an exciting step forward in the management of a very difficult condition. If I were a sufferer of chronic low back pain I would be feeling a little more optimistic after the publication of this research.

Dr Peter Brukner is an experienced team physician and writing in his capacity as CSM co-author, BJSM Senior Associate Editor, and regular blogger. @PeterBrukner

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