How veganism is offering new ways to play our favourite sports
The rise of veganism has seen an increasing number of sports stars convert to the animal-friendly diet.
Tennis star Serena Williams and footballer Jermain Defoe are among the new wave who have spoken of the benefits of switching to ethical eating.
And F1 champion Lewis Hamilton has teamed up with Oscar-winning director James Cameron to find out if vegan athletes perform better.
But not all equipment they use is quite so friendly to animals.
So which sports have started to adapt to veganism and which need to up their game?
Tennis
Most tennis balls are made with wool felt but brands such as Gamma and Prince are ditching the usual coating for synthetic options.
However it might be harder for players to say goodbye to their racket as some of the best you can buy are made with cow intestine.
Natural gut string is favoured by professionals because it can help with control and holds tension better.
Some opt for a hybrid of natural gut and polyester - the winning combination for Andy Murray during the 2013 Wimbledon final.
But for amateur tennis players nylon-based rackets are more commonly available.
Football
Football boots can be made from a variety of leathers, even kangaroo.
The material - sometimes known as K-leather - is used to make Adidas’ Copa Mundial boots, which have been the world’s best-selling football boot since 2001.
Not everyone is jumping for joy over the lightweight shoe as knit and synthetic boots have come into fashion with stars like Lionel Messi and Cristiano Ronaldo favouring the alternatives.
Manchester United defender Chris Smalling has also backed changes to make the sport more animal-friendly by featuring in group [PETA's](http://The world) latest campaign.
League Two football club Forest Green Rovers set the standard by becoming the world’s first fully vegan team, those the players with the Gloucester side aren't banned from wearing leather.
They are however encouraged to stick to a plant-based diet and make environmentally friendly choices where they can.
Considered a carbon neutral club, Forest Green use solar-panelled robots to cut their organic pitch, serve vegan food to fans and sport a kit made from 50% bamboo material.
Cricket
Earley Cricket Club from Reading became the UK’s first vegan cricket club this month and brought in a new ethical menu for all players.
But it was the switch in equipment which made international headlines.
The club have replaced their traditional leather ball with a synthetic animal-free version.
The alternative still reportedly needs improving as it reportedly carries a little bit too much bounce compared to a regular ball.
Horse riding
Almost half of all leather is used to produce shoes, including horse riding boots.
Saddles, bridles and gloves are also made from the material because it’s long-lasting and strong enough to support the weight of a horse.
However, faux-leather riding boots are now an option for eco-conscious riders.
Italian company Fratelli Fabbri launched the first vegan friendly ones last year.
American Football
American football may take a little longer to adapt than most sports.
The appetite for protecting animal rights is hard to see given one team - the New York-based Buffalo Bills - reportedly chows through 500 pounds of beef a week.
But could the sport change its ways?
'Tossing around the old pigskin' is already a thing of the past, because American footballs are made from cowhide not pigs.
Wilson - who have been the official NFL ball-maker since 1941 - use around 22 cowhides to make enough balls for a single Super Bowl.
But synthetic plastic styles of footballs are now available to buy - and could be sold to fans for a fraction of the price.
Ballet
Ballet is more often seen as an art form rather than a sport but there's no denying that dancers put in the athletic hours to nail their performance.
To keep dancers upright, most shoes are made from fabric for flexibility, keeping it a relatively animal-friendly practice.
Alternative ballet shoes have been around for years, replacing the leather sole with a cruelty-free cellulose.
The Royal Opera House spend more than £250,000 on pointe shoes for their dancers each year so they could banish the leather to keep vegans happy.
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