Strength and Numbers

In 2023, to celebrate The Australian Ballet’s 60th anniversary year, the company performed 67 shows of Anne Woolliams’ traditional Swan Lake. This solid block of time spent concentrating on a single ballet presented a unique opportunity for the company’s Artistic Research team (which collaborates with La Trobe University, The Australian Ballet’s Research Partner) to investigate the effects of Swan Lake on the dancers’ tendons – specifically the Achilles tendon, which runs between the calf and the heel, and plays an important part in jumping and running.

Why the Achilles tendon in particular? The team was building on a study done at The Royal Danish Ballet, where researchers tested dancers over six weeks of rehearsals for Swan Lake; they found changes in the Achilles tendon that they speculated would lead to Achilles pain and perhaps injuries in the performance phase. Their study stopped just before opening night. The Australian Ballet’s team sought to follow dancers for a longer period of time to see whether injuries did actually occur.

Ebonie Rio, The Australian Ballet’s Senior Clinical Research Fellow, explains that The Australian Ballet doesn’t have many problems with Achilles pain. The research team were interested to discover if the dancers were able to twirl and leap their way through three seasons of Swan Lake without significant changes to the tendon – and if so, why that might be.

The Achilles tendon gets quite the workout in a professional ballet setting. “Dancers jump a lot,” says Rio. “They jump in class on average about four times a minute. You can think of your Achilles tendon like a spring. A lovely stiff Achilles is one of the main drivers for a jump and gives you a lot of height. Chengwu Guo is a great example of someone with fantastic springs!”

When you think of Swan Lake, you tend to think of the soft, graceful movements of the corps de ballet, but it has quite a lot of jumping and running (which works the Achilles and the calf hard), so it’s a good ballet through which to measure tendon response. It also has a fair bit of standing still, which may have its own stresses. While the principals are performing in the centre of the beautifully arranged swan corps, those swans must hold certain positions for an unusual length of time.

Rio and her team followed the dancers from Melbourne to Adelaide to Brisbane, repeatedly testing the state of their tendons via a method called ultrasound tissue characterisation (UTC), an imaging system that gives a picture of the tendon, with different colours indicating its state. They worked with dancers across all ranks, from principal artists to the corps; they tested both of each dancer’s legs; they tested dancers who were performing in pointe shoes and those performing in flats. The result?

“What we found is that we have a very healthy company. We found no negative response in the Achilles tendon. We also found no differences between the dancers’ left and right legs; nor did any dancer develop Achilles tendon pain.”

The Australian Ballet’s study was conducted with the Brazilian dancer-turned-researcher Bruna Tessarin, who was spending a year with the company as her final PhD study. She collected the data and analysed all the UTC imaging remotely. Rio and Tessarin wanted to be more specific about what was causing pain at the back of the ankle. “Often in research, people will just squeeze the Achilles tendon and say, ‘Oh, you’ve got Achilles pain’, which is really not that accurate,” says Rio. “We progressively loaded the tissues and asked people where their pain was.” First they would try slow single-leg calf rises, which loads the sheath over the tendon. Next would come jumping – focal pain during that exercise would indicate a problem in the tendon. Pain when a dancer pointed their foot to its full extent may indicate an impingement, where the tissues at the back of the foot are squashed and become tender. “By provoking different tissues, we could see which structures are driving the pain. This is hugely important for physios around the world, because Achilles pain is so commonly misdiagnosed.”

The UTC imagery of the dancers’ Achilles tendon showed plenty of green and blue, which indicates healthy, well-ordered collagen fibres. The imagery in the Danish study also showed a lot of green and blue, but had a higher incidence of red and black, which reflects the disorganised fibres of tendons that are reacting to stress. What makes The Australian Ballet different?

“What might be remarkable about our company is the strength of the dancers,” says Rio. “Most of the company can do more than 25 calf rises, and 30 to 35 has been shown to be quite protective in terms of Achilles problems and posterior ankle impingements.” The company’s busy schedule may also play a part. “The dancers do lots of performances, so the workload on their tendons is quite consistent. Tendons actually love being loaded; what they don’t love are big changes in load.”

The Australian Ballet’s dancers look after their bodies – and minds – by incorporating a ‘recovery week’ into their training. Every five to six weeks, they’re encouraged to reduce their gym reps by half. They also have access to other recovery strategies, including cold plunge baths and compression equipment, and to progressive relaxation strategies led by the company’s Performance Lifestyle Advisor, former AFLW and Gaelic footballer Aoife McDonnell. Also, the Artistic Health team are always looking ahead to the next ballet, putting together injury-prevention programs and tailoring the dancers’ body-conditioning programs to support them through the roles they have coming up.

Rio points out that most athletes alternate in-season and off-season periods. The Australian Ballet’s dancers are ‘in season’ for most of the year. But through targeted strengthening exercises like calf rises and cyclical, production-specific management of their workloads, they’re able to maintain healthy bodies, even in the midst of a Swan Lake marathon.