The 2023 FIFA Women's World Cup starts today, and more teams are taking part than ever before. The number of women and girls playing soccer around the world has also increased from about five million in 2014 to more than 13 million in 2019.
Authors
Shreya Mcleod
Course Coordinator & Lecturer, Physiotherapy, Australian Catholic University
Kerry Peek
Senior Lecturer in Physiotherapy, University of Sydney
This greater participation in soccer over the years has led to an increase in injuries, including concussions. These can follow a range of situations, such as when the head hits the ball, players' heads collide, or when the head hits the ground or goalpost.
But are women more at risk than men from such concussions? And if so, why? Here's what the evidence says.
What is concussion?
Concussion is a mild traumatic brain injury that usually happens when someone's head hits something or someone. But it can also happen after being hit on the body, causing a whiplash-type motion to the head.
Common symptoms include headache, dizziness and fatigue. Most soccer players return to play within four weeks of a concussion. Although an estimated 10% of players (particularly women) will have persisting symptoms lasting several months.
Concussions are twice as likely to occur in games rather than in practice sessions. Defenders and goalkeepers have more concussions than forwards or midfielders.
Concussion is more likely as a result of contact between the head and an opponent's elbow or shoulder, head-to-head contact, or contact of the head with the ground or goalpost.
Contact between players (whether head-to-head or elbow-to-head) is more common during a heading duel - when two or more players compete for a ball in the air.
When the ball hits the head
Heading the ball, when players intentionally use their heads to redirect the ball, is unique to soccer. But concussion is more likely after the ball hits the head accidentally.
Regardless of whether such an impact is intentional, there is increasing concern that players exposed to repeated head impacts in soccer, including from headers, are more at risk of developing neurodegenerative diseases, such as dementia, in later life.
But current evidence for this only exists in men. In Australia (and other countries), soccer was deemed "medically inappropriate" for women until the 1970s. So not only have fewer women played soccer historically, their game hasn't been so well researched.
Are women more at risk?
In soccer, and other sports where men and women participate under the same rules, women appear to have much higher rates of concussion compared to men.
For every 1,000 hours of playing or practising soccer, there are about 1.5 concussions for women compared with 1.0 for men.
Women report greater number of symptoms, increased symptom intensity and greater time lost from sport after a concussion.
Concussions caused by ball-to-head contact is also much more common in women and girls, than in men.
So what might be happening in soccer? To answer this, we need to look at several factors, some biological, some related to how women are trained.
1. Neck strength
Women soccer players generally have weaker neck muscles than men. This may place them at higher risk of concussion if they cannot engage these muscles to stabilise their head if it is hit by another head, body or the ball.
2. Hormones
The female sex hormones oestrogen and progesterone may protect women from sustaining a concussion.
Half of concussions also take place in the part of the menstrual cycle known as the late "luteal phase". This is a seven-day window when oestrogen and progesterone levels are declining. However, the research is too limited to speculate further on the role of sex hormones.
3. Training
Women and girls are less likely than men and boys to be trained in how to head the ball, according to an Australian survey of players and coaches. Adolescent players without this training are more likely to report concussion.
Most concussions in soccer occur when two players compete to head the ball. Here, their heads and arms are more likely to make contact, leading to concussion, rather then concussion resulting from hitting the ball itself.
So training players to safely head the ball should include how to position the body to minimise the risk of injury and keeping the eyes open to track the ball's trajectory to prepare for ball-to-head contact.
But 90% of women close their eyes when heading a ball compared to 79% of men, according to one report. This potentially reduces a player's readiness for ball contact, and makes them less aware of any players around them. As a result, they are less able to protect their head against an opponent's elbow or head. However, further research is needed to understand the role of players having their eyes open or shut, and the risk of concussion.
How do we reduce the risk?
Guidelines published last month aim to reduce the numbers of headers in soccer. These approaches are also likely to decrease the number of header duels, a common mechanism of concussion, as well as the long-term risks associated with ball-to-head impacts.
Recommended strategies include:
fewer players, smaller goals - small-sided play (for example five-a-side or seven-a-side) during matches and training for younger, beginner players, plus smaller goals, reduces the number of balls in the air, and headers
playing out from the back - passing the ball out from the goalkeeper to defenders rather than kicking it long the pitch leads to less high-force headers from goal kicks
short corner kicks - kicking the ball from a corner kick to a close-by team-mate is less likely to lead to header duels around the goal
neck exercises - to prepare the neck muscles for heading, neck exercises can be added to injury prevention programs. These can reduce head acceleration and potential concussion in adolescent players
red cards - enforcing red cards (being sent off the pitch) for deliberate head contact reduces the number of concussions.
Under 5% of the 211 soccer associations around the world endorse heading guidelines. So now is the ideal time to explore strategies that keep all soccer's positive benefits while minimising the risk to current and future generations of players.
Shreya Mcleod is a Lecturer and Course Coordinator in Physiotherapy at Australian Catholic University. She is a PhD Candidate at the University of Newcastle, researching concussion in women's contact and collision sports. She is also a Titled Sports and Musculoskeletal Physiotherapist and currently contracts with Cricket NSW. She has previously been a Contract Physiotherapist for Cricket Australia, Hobart Hurricanes WBBL, Singapore Sports Council and the WTA.
Kerry Peek is a senior lecturer (physiotherapy) and sports injury researcher from the University of Sydney. Kerry has received funding from a FIFA Research Scholarship and from Sports Medicine Australia. Kerry is currently an injury spotter (concussion) for FIFA organised tournaments (2023: U20s Men's World Cup and Women's World Cup). Kerry is a member of UEFA's Heading Expert Group and Football Australia's Expert Working Group (Heading and Concussion).
