First Andy Murray looked to Ivan Lendl in a bid to win a first Major, while Novak Djokovic and Roger Federer have responded to very different challenges by bringing in Boris Becker and Stefan Edberg respectively.
Results have been mixed. Djokovic flopped in his title defence, while Federer's flagging fortunes appeared to be boosted by a new fitness routine and some fine-tuning by Edberg, only for his run to end with a straight-sets thrashing by Rafael Nadal.
So far, only Lendl’s influence can truly be called a success, with Murray winning his first two Grand Slam titles – including Wimbledon – and the Olympic singles gold.
It is still early days for Becker and Edberg, and they can only be judged by their charges’ progress come the end of the season.
Edberg seems to have had the bigger immediate impact, with Federer in his best fitness and form for a couple of years; defeat to Nadal is no disgrace, for he is the world number one and also in the form of his life.
But the influence of another, lesser-known Swede is rarely talked about - despite his achievements being of a far greater magnitude. That man is Magnus Norman, the coach of shock Australian Open champion Stanislas Wawrinka.
Norman is a former player who was briefly world number two before injuries prematurely ended his career. He is best remembered for losing to Gustavo Kuerten in the 2000 French Open final, and for being a player who maximised a decent level of talent before entering a rapid and steep decline in his mid-20s.
Even when still playing, Norman was heavily involved with fellow Swede Thomas Johansson, both as a doubles and training colleague and, latterly, a hitting partner. It was around this time when Johansson peaked, becoming a surprise winner of the 2002 Australian Open.
Later, when Norman retired from playing and became a full-time coach, he took Robin Soderling under his wing.
In late 2008 Soderling was a decent but jobbing pro: lingering outside the top 20, he’d won a couple of ATP titles but had never got past the third round of a Grand Slam and hadn’t claimed a title for three years.
Almost immediately after linking up with Norman, Soderling’s career turned around. He started to reach finals again, won a few minor titles and – within the year – found himself in the French Open final after becoming the first man in 31 matches to beat Rafael Nadal at Roland Garros.
It was no fluke. Things got better and better for Soderling as he reached the quarter-finals at the US Open, then reached a second French Open final in 2010 before making the last eight at Wimbledon and once more in New York.
Wawrinka is Norman's latest project - and his latest success. ‘Stan’, as the Swiss is known, had developed a reputation as a powerful, attacking baseliner with huge shot-making ability and natural aggression, but a tendency to fold under pressure against the biggest players.
A popular face on the tour, Wawrinka would regularly reach the finals of ATP tournaments, but lose to the ‘big four’; in the Grand Slams, he would impress in the early rounds but again fall to pieces against the world’s best.
As a result, Wawrinka, in his mid-20s, seemed to have plateaued in or around the top 20. Sound familiar?
All that changed last year, when Norman came on the scene. The impact was almost immediate as, a few months into their relationship, he managed to see off David Ferrer to win a clay-court tournament in Portugal.
He was then able to oust defending champion Andy Murray in the US Open, and undeterred by his semi-final defeat to Novak Djokovic, impressed at the World Tour Finals before his epic triumph in Melbourne.
Wawrinka – like Soderling and arguably Johansson before him – has become a completely different player, one maximising his ability under pressure instead of crumbling when it matters. Last season he finished the year as a top-10 player for the first time, and his Aussie Open triumph has pushed him into the top three – all at the age of 28, approaching veteran status in tennis erms.
So how does Norman do it?
He has set up a tennis academy with friends and former Sweden team-mates Nicklas Kulti, Mikael Tillstrom. They formed part of a ‘golden generation’ of over-achieving Swedes, which culminated in winning the Davis Cup in 1998.
“We have one thing in common,” their website says. “We have all taken the step from (being) good tennis players to world class professionals.”
Their academy is even called “Good To Great”, and they take pride in their relatively small size and lack of facilities, instead focusing on tailor-making training routines to suit each individual.
Wawrinka is their star client. Obviously it is working for him, and some of the Swedish youngsters on their books – such as teenage brothers Elias and Mikael Ymer (who are top-ranked in their age groups) – have been tipped as stars of the future.
Certainly you can expect others to start banging on his door. But I would expect Norman to channel his energies towards Wawrinka, in whom there is a sudden challenger to the established stars of world tennis.