Category: Contributor’s corner

The Knee-d to run

by Shana-Lee Bownes

Lockdowns that had us all cooped up in our homes for over a month seems to have sparked a greater appreciation for exercise in us all. Who can forget how ironically crowded the Cape Town beach front walkway was on the 1st May 2020 with walking folk and runners eagerly tottering about with mask-concealed smiles.

Running is arguably one of the most accessible forms of exercise and a popular choice adopted by many trying to stay fit and get outside, especially during the hard lockdown. A survey conducted by De Jong and colleagues (2021) about running during the pandemic found a small but significant  increase in running mileage of 1,4km per week (great) but also a 1,4 times the injury risk compared to before the pandemic (not so great)(DeJong, Fish et al. 2021).

Here’s the story: We dust off out running shoes and hop on the road. The first few training sessions are rough, but then they get easier and that’s when the bug bites. Suddenly you’re up at 5am on a Saturday for your long run and posting a snap of your coffee #postrunfeels. But that little niggle in your knee that gradually builds up as you run is still there and often when niggles are ignored they have the potential to turn into more serious injuries. When looking at the studies published in running injuries van der Worp and colleagues found that injury was reported between 19,8-25% in men and 79,1-79,5% in women who run (van der Worp, ten Haaf et al. 2015).

Research on running injury prevention has unfortunately been somewhat inconclusive. Messier and colleagues have undertaken a very important step to improve research in this area by unpacking all of the different factors that contribute to developing running injuries. Over a two year period they followed 300 runners, testing running specific, physical and psychological characteristics. During the study 66% of participants sustained injuries in the two year period. Expressing more negative emotions, being a female and knee stiffness was associated with injury, this is unsurprising considering knee injuries were most commonly reported. Knee stiffness, especially in those weighing 80+ kilos, significantly increased the chances of developing one of those pesky overuse injuries (Messier, Martin et al. 2018).

So, where to from here? Hopefully with this knowledge we can focus our efforts on discovering the mechanisms by which these risk factors contribute to injury. Hopefully by addressing these risks we can come up with strong preventative measures. Measures will translate well into the running community and when implemented – will protect us against injury.

Until then in the wise words of Dean Karnazes: “Run when you can, walk if you have to, crawl if you must; just never give up.” (Meuller 2020)


DeJong, A. F., P. N. Fish and J. Hertel (2021). “Running behaviors, motivations, and injury risk during the COVID-19 pandemic: A survey of 1147 runners.” PLOS ONE 16(2): e0246300.

Messier, S. P., D. F. Martin, S. L. Mihalko, E. Ip, P. DeVita, D. W. Cannon, M. Love, D. Beringer, S. Saldana, R. E. Fellin and J. F. Seay (2018). “A 2-Year Prospective Cohort Study of Overuse Running Injuries: The Runners and Injury Longitudinal Study (TRAILS).” Am J Sports Med 46(9): 2211-2221.

Mueller, S (2020). “60 Inspiring and Motivating Running Quotes” [online] Planet of Success. Available at: <; [Accessed 11 April 2021].

van der Worp, M. P., D. S. ten Haaf, R. van Cingel, A. de Wijer, M. W. Nijhuis-van der Sanden and J. B. Staal (2015). “Injuries in runners; a systematic review on risk factors and sex differences.” PLoS One 10(2): e0114937.

The Shot Heard Around the World: Achilles Tendon Injuries

by Ashleigh Thomas

If you’ve heard or experienced an achilles tendon rupture, you’ll know exactly what the title is alluding to. If you don’t know, an achilles tendon rupturing sounds like a gunshot, and it’s as painful as it sounds. Researcher Gregory Hess, in his 2010 review of “Achilles Tendon Rupture” in the Foot and Ankle Specialist Journal, writes that the number of sporting injuries is increasing with the increase in sport participation. The most common injury; achilles tendon injuries. This begs the questions: how can we avoid them (and the months of no sport participation and gruelling rehab) and who is most vulnerable?

Schepsis, Jones and Haas (2002) comment that the increase in sport-related achilles tendon injuries as going from 2 to 12 cases per 100 000 in less than 10 years. Typically, this occurs in males during their 4th and 5th decade of life (Schepsis et al., 2002). The injury also appears to occur most commonly in racquet sports such as tennis, squash, and badminton (Schepsis et al., 2002:298). It appears that this injury is the achilles heel of middle-aged male squash players.

It is important to understand the mechanisms of this injury. Hess (2010) explains that 53% of reported cases are due to the push-off mechanism (off the weight bearing leg with the knee extended). Other mechanisms include unexpected ankle dorsiflexion and violent dorsiflexion of a plantar flexed ankle during running/jumping/agility activities/activities involving eccentric loading/explosive plyometric contractions (Hess, 2010).

Figure 1: The anatomy of the Achilles Tendon

The achilles’ structure and function are also pieces of the puzzle. The achilles is an extension of two independently moving muscles, the gastrocnemius and soleus muscles, and it attaches to the posterior heel bone. The tendon is primarily composed of collagen which forms cross-links that allow it to resist high tensile forces (Hess, 2010). Forces stretching the tendon beyond 4% result in some of these cross-links failing and stretching beyond 8% is likely to result in a rupture (Hess, 2010).

Additionally, defects in the tendon’s structure could result in a rupture as it has a poor nutrient and blood supply (Hess, 2010). A rupture is also likely if degeneration and overloading occur repeatedly over extended periods of time (Hess, 2010). Therefore, it makes sense that the proposed processes for achilles tendon degeneration and rupture are tendinosis and chronic tendinopathy because these conditions cause an imbalance between tendon degeneration and repair (Hess, 2010).

How can we identify individuals who may be at risk of experiencing such excruciating pain? Through research, a number of intrinsic and extrinsic factors which predispose individuals to sustaining a rupture have been identified. The presence of these can increase the likelihood of a rupture. These factors, as described by Hess (2010), are seen in Figure 2.

Figure 2: The extrinsic and intrinsic factors predisposing individuals to achilles tendon rupture adapted from Hess (2010).

Individuals exhibiting these factors should take extra precaution as Hess (2010) writes that a combination of these factors reduce the tensile strength of the tendon and contribute to faulty biomechanics and compensatory mechanisms which can evolve into a tendon rupture. A key factor that Schepsis et al. (2002) emphasizes, and which Hess (2010) agrees with, is the degenerative effect of natural ageing on the tendon resulting from decreased blood flow, decreased collagen tensile strength and increased tissue stiffness (Schepsis et al., 2002). These aging effects reduce the tendon’s ability to handle stress, predisposing it to injury.

All is not lost; there are things you can do to try to prevent this from happening. A rupture could be prevented by avoiding degenerative changes in the tendon by doing regular physical activity, and by allowing adequate rest following tendon injury (Hess, 2010). Eccentric strengthening of calf muscles has also been linked to prevention of rupture (Hess, 2010). However, we still have many questions to answer before we can say for certain what the best method of prevention is. This also speaks to the gap in this area and research going forward should focus on the implementation and the effectiveness of prevention programs.


  • Hess, G., 2010. Achilles Tendon Rupture. Foot & Ankle Specialist, 3(1), pp.29-32.
  • Schepsis, A., Jones, H. and Haas, A., 2002. Achilles Tendon Disorders in Athletes. The American Journal of Sports Medicine, 30(2), pp.287-305.
  • de. 2021. Achilles tendon – anatomy and importance. [online] Available at: <; [Accessed 9 May 2021].

Rugby and CTE

By Ken Quarrie 

I have been seeing claims that some people are “sowing doubt” with respect to CTE (Chronic Traumatic Encephalopathy) and are thus acting like tobacco companies did with respect to heart diseases and lung cancer. I want to make a few comments about this. Before I get to the CTE issue, it is worthwhile that I put some background about me on the record, so that people are able to judge whether I am likely to have biases that might sway me to one position or another.

I was brought up in New Zealand, in a family where rugby was *very* important. Dad played rep rugby for Wanganui and Waikato, and was an All Blacks triallist. As a kid I was a fan and obsessively read books about rugby and the All Blacks. I played the sport from childhood until my late 20’s. I had some really enjoyable times along the way. I also sustained (at least) five concussions. I was immersed in the Otago Uni/Dunedin rugby heavy drinking culture.

I found that as I got older there were fewer aspects of the “rugby” culture with which I identified – @XTOTL captures some of that here: I also had a good friend injured at the age of 15 in a scrum. He has been in a wheelchair since 1984.

As well as rugby, as a kid I loved science. I have managed to combine those two loves into a career. I wouldn’t call myself a rugby “fan” anymore. I am a rugby scientist, and it helps to have a little distance from your object of study. Nevertheless, I still work for NZ Rugby (conflict of interest klaxons!). Having worked on independent research studies examining risks for injury in the 1990’s, I took a role with NZ Rugby in 2000 as their first “Injury Prevention Manager”. I realised that, as a scientist, my employment represented a conflict of interest, but I believed I could have a greater impact on improving player safety and welfare from within rugby than from the outside.

I have been adamant with NZ Rugby and World Rugby that I must be allowed to conduct research without interference about what I can study, how I can analyse it, and what I can say about it. A look at my research outputs will reveal an eclectic mix of rugby studies. So when people “poison the well” by implying that any research funded by or conducted by sports organisations must necessarily be “suspect” I feel personally attacked. Doing good science is what I care about.

Doing good science is what I care about.

From a personal level, the welfare of players has, and does, take precedence for me over considerations of “tradition” or “maintaining the essence of the game”. But managing risks does not imply “eliminating all risks”. Reasonable people can look at an issue and disagree about it.

So – the “tobacco company line”. Tobacco companies systematically downplayed the risks of their products, and attempted to “sow doubt” in the public mind. How is the CTE/concussion debate different? A key difference is that, despite there having been strong claims made about what causes CTE, how it develops, and what clinical outcomes it leads to, the reality is that the science of CTE is very young. There really *is* a lot of doubt about a number of the issues!

The issues include whether CTE is, as has been claimed by some, a primary, progressive neurodegenerative disease. Questions remain about the cause(s) of the pathology. Questions remain about the “pathognomonic lesion” – i.e. what distinguishes CTE from other pathologies. Questions remain about the prevalence of the pathology. MAJOR questions remain about the relationship between having CTE pathology in the brain and any given clinical outcome. Do I think brain injuries are bad for health? Yes, undoubtably. I also think that the public perception of the strength of the evidence, and the prevalence of CTE as a public health issue doesn’t match the scientific understanding of it *at this point*.

So to accuse “rugby” as having acted like tobacco companies to sow doubt about CTE is simply a smear, and a lazy and demonstrably false one at that.

If former rugby players are struggling – for whatever reason – my heart is with them. I pledge to do my best to understand more about the long term health outcomes of playing rugby, so that people can better understand the risks and make informed choices about play. People involved in rugby, like Colin Fuller, @Sharief_H, @drkeithstokes, @drsimonkemp, @mattjcrossie, @Scienceofsport and yours truly and many others have identified and documented risks in rugby via research studies and injury surveillance. Many changes to rugby have been made as a result of that work. RugbySmart, BokSmart and other injury prevention programmes have been widely recognised within the sports science/sports medicine communities as having had positive effects on the risks of injuries. Likewise, the @NZRugbyFound has done great work on tertiary prevention. So to accuse “rugby” as having acted like tobacco companies to sow doubt about CTE is simply a smear, and a lazy and demonstrably false one at that.

Ken Quarrie is the Chief Scientist for NZ Rugby. All views expressed are his own, and do not necessarily represent the position of his employer. The above article was compiled, with permission, from a thread of tweets by @KenQuarrie. For more on the topic, you can follow Ken at @KenQuarrie. You can also view Ken’s publications here – Ken’s Google Scholar Profile.