Is it possible to compare the risk on the rugby field to climbing a mountain?
You take a risk every time you run out on the field, hop on your bike, or tie your tramping boots.
Overall, the risk of serious injury or death from sport and recreation is extremely low.
But there's almost always some risk.
At the weekend in the United Kingdom, Hull City footballer Ryan Mason fractured his skull in a sickening head clash with Chelsea's Gary Cahill in an English Premier League match. In Wellington this month, Bangladesh cricket captain Mushfiqur Rahim was concussed after he ducked into a 135kmh delivery from Tim Southee and the ball struck his helmet.
So, how dangerous is sport?
Defining the world's sport and recreation in terms of danger levels is not an easy task, mainly because comparing, say, motor sport with tramping, presents problems.
So, there are a few things to consider first. Any team sport with a ball, anything with horses, or water, and any sport involving a vehicle, runs a risk of injury or death. That's part of the attraction of taking part and playing.
Comprehensive statistics are hard to come by and the data is limited. Governing bodies, understandably, do not go out of their way to publicise injuries and deaths. Participation figures are also hard to come by but figures on injury claims in New Zealand are available through the Accident Compensation Corporation, although these do not tell us how many people play a particular sport.
Auckland University of Technology human performance professor Patria Hume has studied sport injury rates in New Zealand since the 1990s.
"New Zealanders are passionate about sport. Sport has positive health benefits but also some negative injury consequences.
"ACC and national sports organisations make a concerted effort to reduce injuries via programmes. The question is, has the incidence of injuries decreased, and are the same sports still rated in the top ten for injury incidence?"
A study in the New Zealand Journal of Sports Medicine co-authored by Hume explored sport injuries from 1978 to 1987 by tracking injury hospitalisations and found rugby union was at the top. Other sports with a high injury rate were horse riding, football, cricket, netball, rugby league, basketball, and skiing.
"The body sites most frequently injured were the head, face, ankle, trunk/spine, lower leg and knee. The most frequent types of injuries were fractures, sprains/strains, dislocations and contusions.
"The most common events resulting in sports injuries were striking or being struck by objects or persons, falls, and over exertion."
Hume said an analysis using 2014 data showed the same sports, bodily injuries, and types of injuries continued to occur.
However, given increased public awareness, improved technology and equipment, and efforts by governing bodies, some sports have become less risky.
"Comparison of rankings in 1989/90 compared with 2014 shows that success stories in terms of decreasing ranking were horse riding, cricket and snow skiing.
"Fitness training/gym now appears at number three whereas it was not frequently reported in 1989."
An increase in gym-related injury claims may be related to new reporting requirements or an increase in the number of people attending gyms, Hume said.
The "top five" in terms of injury claims were rugby union, football, gym training, netball, and cycling.
Recent Mountain Safety Council research into injury rates in the outdoors provides an eye-opening overview of how recreation can go awry.
Findings challenged common assumptions of who was getting hurt, lost, or killed.
Three-quarters of search and rescues involved Europeans, including European New Zealanders, and 67 per cent of tramping fatalities involved Kiwis.
Mountain Safety Council spokesman Nick Kingstone said injury rates in outdoor pursuits were not studied in depth until the council collated all the available data in a report in 2016, There and Back.
In terms of injury rates, risk, and type of activity - sport or recreation - there was no single source, he said. This was a common problem with big data.
"There really is no single data source. It's about participation rates. For example, mountaineering is pretty dangerous in terms of injury rates [relative to participation].
"Mountaineering is one of the most risky activities you can do [outdoors]. When you step back and look there's very little we can do to make it safer. The environment these guys are going into you can only risk manage 70 per cent.
"People take a PLB. It doesn't make you safer. It makes you easier to find."
Kingstone said more than one factor was often at play in causing injuries. Misconceptions were involved too, with many people wrongly assuming the majority of injuries or fatalities involved foreign nationals.
"Your risk is things that exist in the environment. You're interacting with a hazard and that interaction is the risk.
"In mountaineering, if things go wrong in that environment the consequences are relatively high compared to something like tramping. The exception to that is river crossing.
"You can rank loosely which are the most dangerous but it's slightly biased because the highest participation rates are hunting and tramping.
"With fatalities, very nearly 70 per cent of all tramping fatalities are Kiwis and the next big lot are Aussies.
"With hunting, 54 per cent of all fatalities had nothing to do with the firearm. There's a huge risk to hunters falling and crossing rivers."
In New Zealand, ACC has information on the number of new claims - almost 500,000 sport and recreation claims in 2013/14. There were 1.8 million claims overall but this information doesn't tell us sporting participation rates, the causes of injuries, or the types of injuries.
Participation rates are crucial to give a clear picture of the risk. Active New Zealand's survey is the closest we have to a snapshot in terms of who does what and where - walking, swimming, cycling, the gym, fishing and running are the most popular.
Hume was a co-author of a 2013 article in the Journal of Science and Medicine in Sport exploring sport-related concussions in New Zealand using 10 years of ACC claim data.
There was no system for recording concussion rates through the national sport organisations and no reliable participation figures for the various sports.
Rugby union and football had the highest number of claims from 2001-2011. For men, the top five in terms of concussion claims were rugby union (with 735 claims in 10 years), rugby league, football, touch rugby, and hockey.
For women, the concussion rates were much less and the top five sports by claims were netball, rugby union, football, touch rugby, and hockey. The numbers do not tell us how many concussions occur by sport, but do tell us the number of recorded injuries.
"[Although] sport-related concussions may be minor in severity, the related economic costs attached to a sport-related concussion with ongoing symptoms can be high. The finding that rugby union recorded the most claims was not unexpected as this is the national game in New Zealand.
"Previous international studies have identified that ice hockey and the national football league [American football] have some of the highest incidences of concussion of all sports but these sports have low participation levels in countries such as New Zealand."
The overall picture is far from complete and it is impossible to meaningfully compare, for example, motorsport with football or tramping.
There's a greater risk of injury in almost every activity involving contact, projectiles, water, vehicles, and altitude.
Increasingly, governing bodies are more aware of the risk. Helmets and body armour are much more common these days.
In rugby, concussion awareness and research continue to grow.
Fishing, for example, is a risky sport, due to drownings, but it's not considered dangerous or widely perceived as such.
About 100 people drown in New Zealand each year.
There doesn't seem to be any useful figures on, for example, injuries per capita by sport. Ranking sports by danger levels is not straightforward, partly due to varying participation levels, which goes some way to explaining why popular sports cause more injuries.
Very few studies have been done on injury rates in women's netball, according to the New Zealand Medical Journal.
One New Zealand Medical Journal study of mountain climbing, a high-risk sport, said almost half of the climbers studied had been injured.
"At baseline 47 per cent of climbers had been involved in accidents. Serious accidents involving multiple bone fractures, head, and spinal injuries were not uncommon and interestingly has not dissuaded many climbers from continuing," the article said.
In a University of Canterbury study of cricket injuries, data suggested half of all injuries were suffered while bowling, which presents a risk of lower back, knee, and shoulder injuries.
Contact sports and any sport exposed to the environment runs the risk of injury.
In the US, American football is responsible for many injuries, alongside basketball and cheerleading.
Jon Hopkins Medicine in the United States says sport causes around 3.5m injuries out of a sporting population of 30m. Half of all head injuries occur during bicycling, skating, or skateboarding but the highest rates of injuries occur in contact sports.
The National Centre for Catastrophic Sport Injury Research recorded 15 deaths from high school baseball between 1982 and 2015, one death from cheerleading, and 126 deaths from (American) football.
The centre tracks fatal, non-fatal (where injury is permanent and leads to disability), and serious injuries across all sports for school-age participants.
Its 2015 annual report said American football was the most common injury causing sport.
"The majority of events occurred to athletes participating in the following sports: football, basketball, football, and baseball.
"For high school sports, football had the highest number of direct catastrophic events, followed by female cheerleading, baseball, wrestling and track and field."
Bear in mind, though, injuries are common and, in 2015, an estimated 345,000 people in the US were injured by clothing, 48,200 by grooming devices, and 16,280 people were injured by blankets.
In football lower body and limb injuries are most common.
Motor sport, horse riding, water sports (think cave diving and big wave surfing), and extreme sports such as wing-suiting all present an element of danger and, in worst case scenarios, serious injury or death is possible. A worst-case scenario in, say, tennis, is unlikely to be fatal.
A rodeo is dangerous if you're bull-riding and then we have bungy jumping, sky diving, heli-skiing, downhill mountain biking and boxing.
There's also a big difference depending on how we define danger.
Is it the risk of injury? Or mortality rates?
If it's injuries, then sports such as rugby, football and cricket have higher rates of injury. After all, these are contact sports and, importantly, they are very popular. The more people play, the more injuries.
A study in Australia by the British Medical Journal, analysed a two-year window for all sport in Victoria.
Overall, the study said, the risk of serious injury was around 1.8 in every 100,000 participants per year. Motorsport, power boating, and equestrian sports had the highest rates of serious injury while most deaths were due to drowning.