As Essendon fights latest injury crisis, a look at how sleep, stress and genetics factor into the make-up of an athlete's health

Australia Broadcast Center

17-07-2025

"Injury crisis" is a phrase no sporting organisation ever wants to have associated with it.
Injuries are arguably the most debilitating part of professional sport and often disrupt even the best-laid plans.
This year, the AFL club finding itself hit with an all-time injury bug is Essendon.
The Bombers weren't tipped to be a premiership contender coming into 2025, but any hopes of a forward step in Brad Scott's third season as senior coach have been rendered virtually impossible due to the club's lengthy injury list.
Persistent injuries to many of Essendon's best players have resulted in Scott being forced to unearth 13 debutants this year, the most by an AFL club since Fitzroy in 1991.
Young midfielder Elijah Tsatas is the latest Bomber to be ruled out after suffering a hamstring strain, making him the 11th Essendon player to have a soft-tissue injury this season alone. Of the 11, Kyle Langford, Darcy Parish, Mason Redman and Zach Reid have all suffered repeat injuries.
The spate of injuries has led to calls for an overhaul of Essendon's medical staff, with the club currently reviewing the entire department.
However, the solution isn't always that simple. There are a number of factors Essendon, and other clubs pondering a change in medical staff, have to weigh up.
Kusal Goonewardena is the director of Elite Akademy Sports Medicine, and looks after elite athletes at the University of Melbourne.
Having assessed countless athletes across various sports in his career, which spans more than two decades, Goonewardena explained how strength and conditioning make up just a small part of an elite athlete's health status.
Goonewardena uses his "K-Theorem", which offers a visual explanation of how various elements come together to impact an athlete's body.
"There are many aspects that make up an athlete," he told ABC Sport.
"We try to identify what a person does in their 24-hour cycle, for example, how much they sleep, which is very important in recovery, how much exercise they do in terms of training, and what they do outside of sport and outside of training.
"Even aspects of how a person sits, spends time on their computer, posture, plays a big part in the performance of the biomechanical elements. Then there's the nutrition and the mind.
"If we're talking about the AFL, primarily we're looking at hamstring injuries, that's the most common type of injury there is. You could have the muscles being completely affected by all these other areas."
Goonewardena is a big believer in the correlation between stress and the likelihood of players getting injured.
"If a person is stressed, there will be a direct relationship to what happens in their muscles and their joints," he said.
"If you're very much under stress, you will note that all your muscles are tight.
"During exam periods, most of our elite athletes have been sitting and studying and are stressed, and they are naturally tight."
In an AFL environment, stress can manifest for a player in a variety of ways. Players can be stressed about their own individual performance, the team's performance, their position in the team, or a potential big contractual decision coming up.
Goonewardena compared the pressure on a player in the middle of his or her career to one who has at least privately made the decision to retire at the end of any given season.
"Another impact stress levels is if a person's position is under pressure, if they're not sure whether they'll continue playing in the coming weeks," he said.
"You see this a lot when an athlete has decided to retire, they're not going to really push themselves at the highest level. There aren't many cases that I've seen where a person is about to retire, or they're voluntarily retiring, and then they pull their hamstring."
Stress can also come in the form of psychological warfare from an opponent.
Goonewardena recalled an occasion where he was working with Germany's Laura Siegemund at the 2021 Australian Open, where Siegemund was pitted against Serena Williams in the opening round.
Williams wound up winning the contest 6-1, 6-1, but Goonewardena remembered how the match essentially began before the two players even took to the court.
"If you're a top-five player, you have your own warm-up area, and you can have your full entourage there, you don't need to go with anyone else. I think Laura at the time was world number 50," he said.
"What Serena did was she brought her whole entourage, about 12 or 15 people, and came and trained where everyone else was training.
"Where Laura was warming up, she warmed up maybe three to four metres away, and that was enough to create a certain stress level. Serena's not doing anything, but it was all psychological.
"When you're psyching someone out, you're creating a stress level in performance.
"When a performance drops, the athlete needs to try and optimise themselves to try and continue to perform, and you need any of the biomechanical elements to fire up more, therefore something can give."
Stress also has an impact on a player's sleeping habits, something Goonewardena calls the most important thing when it comes to recovery.
"If you've had a stressful game, if you've pushed yourself, you're not sleeping well," he said.
"Sleep is so vital for recovery, it's probably the number one thing. It's also why sleep deprivation is a torture technique. You keep someone up for 36-72 hours, and they go nuts and start talking about anything."
Red flags have gone up regarding Essendon's medical staff this year due to the number of repeat injuries.
Langford has twice injured his quad along with his hamstring, Parish has injured his calf twice, Reid has hurt his hamstring twice, and Redman has hurt his calf and his hamstring on separate occasions. Langford, Parish and Reid are all but certain to miss the remainder of the season.
Goonewardena believes it is not just problem areas, such as hamstrings, that should be assessed, but rather the entire body when it comes to players who have recurring issues.
"My expertise as a sports physio is to get a full understanding of their biomechanics," he said.
"So we measure every aspect from the nerves, muscles, joints and ligaments from the head down to the rest of the body.
"A lot of people ask why we do it from head to toe, and what I say is, to get the perfect kick, you need a lot of things happening. You need to have good posture, you need good head-positioning, you need good shoulders, you need good positioning of the hips, glutes to be upright on the non-kicking leg, and then you can use that to kick really well. It's all about the form.
"If people said the people with the biggest quads or biggest legs kick the furthest, that's actually incorrect, it's everything else that comes together to create that perfect kick.
"So if the person needs to have all these systems coming together to execute this perfect kick, then as a physio, I should be able to assess the whole body and make sure the whole body is fine, and then we can say here is the area that is not up to scratch.
"Sometimes a hamstring injury can occur, say on the right hamstring, which might be the kicking leg, and it might be because the other side has some major problems.
"I have found that the majority of the problems for hamstring issues come from the mid-back.
"As a young physio, we were taught to look at the hip and the lower back. What I'm finding more and more now is that we need to look between the shoulder blades as well. When we say the thoracic spine is not working well, it comes down to the thoracic spine's mobility or range, thoracic spine control and then how it relates to the core as well. That's just one aspect of hamstring issues.
"Once I've worked out which elements aren't working well, I look to see how those elements are affected in a 24-hour cycle. If that thoracic spine is tighter or not moving well, especially after training, it could be a loading issue. If it's not working well after people have spent a lot of time on their computers or the sedentary part of their day, then that's an issue. Or is it something after sleep?"
Goonewardena believes tailor-made training programs for individual players are vital in elite sport nowadays.
Certain athletes may be more prone to injury in specific climates, or may experience flare-ups in particular areas of the body compared to their teammates.
"We're finding that athletes' training programs have to be completely customised to them in the same way a nutrition plan has to be completely customised," he said. "It shouldn't be a one-size-fits-all approach."
"We had a Sri Lankan cricketer, and we did a DNA sports performance test on him, and his DNA showed that he had a very low tolerance to cold weather exposure.
"In Sri Lanka, before they come to a place like Australia, New Zealand or the UK, they go and do a two-week camp up in places with cooler climates, like Nuwara Eliya or Kandy, but he should be doing four, because his DNA needs that. If he had spent a little bit more time in Nuwara Eliya training, by the time he came here, he would've had a lesser chance of injury."
Goonewardena explained that while DNA testing is something that isn't universal just yet, it is something that can benefit and prolong a player's career.
"When I spoke about the DNA testing with Laura (Siegemund), she said, 'Oh wow, this is interesting, I'd like to get it done,'" he said.
"At the same time, I was working with Vera Zvonareva, a former world number two … and she said, '20 years ago, we got this done in Russia,' so there are countries that do it (more readily). Vera is a strong example, she was playing up until she was 40.
"It does help with longevity, but it also gives you an understanding of how to customise things.
"That part of the research hasn't been delved into deep enough yet, but it showcases that your DNA will affect how the muscles and joints work, how your muscles respond, how much exercise you need to do, but it then becomes completely customised."
Managing players' workloads is a major part of a team's medical staff nowadays.
This can be particularly important when it comes to players who are rehabilitating an injury, and even more important when that injury is one that has proven to be recurring.
In the case of Essendon, the Bombers have taken a cautious approach to managing players with a history of soft-tissue injuries since Scott took charge at the end of 2022.
Unfortunately for the club, even with this conservative approach to injury rehab, the number of injuries seems to have increased.
Goonewardena believes being over-conservative can also be something that hampers a player's recovery process.
"It's not a good thing. The human body is there to perform at its highest level," he said.
"Say you have a Formula 1 car that's fully optimised and the engineers have done their work on it, it's built to go at 300km/h, but you say no, let's just take it at 100, it won't perform as well.
"It's very similar. If you're ultra-conservative and your soft tissue injuries are dropping, great, it worked. If injuries are still occurring, then something else is the issue.
"Movement is medicine for the body. If you limit a person too much, it's not very helpful.
"Back in the 80s and 90s, for any person with back pain, doctors would say, 'Seven days bed rest and after the seven days, you can do everything', but in those seven days, the nerves, muscles, joints and ligaments haven't been optimised.
"So it has to be a gradual approach. The approach I use is, if you can do something and there is no indicator of pain, plus you get the proper movement pattern, go and do it.
"If we base everything on pain, that's also bad because pain is very subjective."
According to Goonewardena, a player who might be on the fringes of an AFL team and not playing consistently is at a higher risk of injury compared to someone who has a consistent routine.
Goonewardena used the example of Essendon captain Zach Merrett, who is rarely injured, as someone whose routines and meticulous preparation likely allow him to avoid the fate that has befallen many of his teammates this season.
"The person who has consistent loading, if they don't maintain the recovery, then you're asking for trouble," he said.
"Someone like Zach Merrett probably has very good processes and systems for recovery. Recovery comes in many forms — sleep, compression, massages, ice baths, even things like red light therapy.
"He has probably worked that out, and he is going to be able to perform at the highest level he wants without concern of breaking down.
"Someone who's up and down, there are a few elements. In a week where they're up, they might have good process, and the week that they're down, they're more likely to say, 'Hey, I don't need to do that,' so you don't get a solid and proper trend.
"That would then lead to the day he goes and has a high-load game and says, 'Don't worry about the ice baths today,' … something gets missed. So, more than the up and down nature of the [playing] loads, it's [important] to make the recovery consistent."
The method of training is also an important factor in preventing player injuries.
"When you're not training in the right way, you're overloading on the incorrect thing," Goonewardena said.
"Say you get hamstring issues … they say, 'I need to get my hamstring stronger', and then they say things like, 'Oh, I need to build up a good core because if I had a good core then my hamstring would be stabilised', so they take a top-down approach.
"They go and do strength and conditioning and work on their core, but the biomechanical aspects that make up all of this — the nerves, muscles, joints and ligaments — are not assessed. If you over-train with strength and conditioning, then there's a certain level of fatigue that you're going to create.
"Back in the day, there wasn't enough awareness about strength and conditioning, and now I feel like that's there. But that has also created this misconception that the stronger you are, the better you'll be.
"I've seen that in cricketers, they'll go and do these deadlifts and some of them try to prove a point by doing a certain level of deadlift, but it's not functional for cricket, it's not cricket-specific.
"There's still a lot that I haven't seen enough, which is being sport-specific and athlete-specific."
Athletes are often required to play through certain levels of pain. As a season wears on, that can mean players are carrying little knocks and 'niggles', a commonplace in footy vernacular.
Goonewardena assesses athletes' health in three zones — green, yellow and red, and these assessments can prove crucial in managing and ultimately avoiding injuries.
"If you don't have an injury, you're in the green," he said.
"If you're in the yellow zone, what that means is there is a bit of tightness in the body, and the movements are apprehensive. If that's there, that is a warning sign already.
With hamstrings being the most common injury in Australian rules football, Goonewardena said the platform for the injury itself is usually laid well before the player pulls up.
"The majority of football hamstring injuries occur close to where the kick is, usually when they're kicking, or in the running phase. That means that every footballer should have this kind of problem, because they all do it, but then some people don't have it. Why is that?" he asked.
"It comes down to the concept of the straw that breaks the camel's back. That one last straw for many footballers is when they are running or when they are kicking, but it's because some of the other aspects didn't fall into place.
"If I'm looking at the biomechanics side, let's say something about muscle weakness or tightness, there might be a nervous tissue problem, so the nervous system might not be optimised.
"Some of the joints in the rest of the body might not be optimised, so it could be tightness in the mid-back, or sometimes even tightness in the shoulder.
"They might not be sleeping well, they might be under-training or over-training, because everything is about muscle memory.
"So all these straws come together, and the place it gets pushed the hardest is on the field."