“Any professional tennis players that played as professional footballers as well?” tweets Jack Chesterman.

James Clarke raises his hand. “Michael Boulding played professional tennis until the age of 22, peaking at No 1,119 in the world,” he writes. “He went on to sign for Aston Villa a couple of years after retiring, but only made one appearance, and then floated around the lower tiers of the Football League for a while.

“His Wikipedia page brings up a trove of possible past or future Knowledge answers. So in case these were ever answers to different questions: he played with his brother, Rory, at two clubs (Mansfield and Bradford); had multiple spells at three clubs (Mansfield, Grimsby and Barnsley); and his sister, Laura, played rounders for England.” Quite the family of achievers: Helen Boulding is a noted musician and songwriter, having toured with Bryan Ferry, contributed vocals to music by the Orb, and – crucially – co-written this for 911.

Michael Boulding recalled highlights from his tennis career to Grimsby fan-site The Fishy: “I was deported from Yugoslavia. I landed in Belgrade and didn’t have a visa. They interrogated me, kept me in overnight and then deported me the next day. I got chased through the streets of Sofia by loads of blokes from the black market who were trying to rob us. I crashed a jetski in Thailand after seeing a tiger shark in the water.”

Paolo Maldini dabbled in doubles a couple of years ago, as reported here by Jacob Steinberg and tweeted in by Paul O’Neill. It didn’t last long … “He played a doubles tournament in Italy in 2017 as a wildcard. It was on the Challenger Tour (the level below the ATP Tour) with a bit of prize money up for grabs. He lost in the first round and never played pro again.” Alongside Stefano Landonio, he lost 6-1, 6-1 against Tomasz Bednarek and David Pel.

“Rangel Rangelov,” head-nods Teodor Borisov. “He had two Bulgarian cup finals (1956 v Botev Plovdiv, 1960 v Lokomotiv Plovdiv) and participated in the 1964 and 1967 Davis Cups.” While the 1964 edition, Bulgaria’s debut, saw them exit at the first time of asking, 1967 was a tale of two tonkings – Rangelov didn’t drop a set across two singles matches and a doubles match in a 5-0 win over Portugal. Next up were Great Britain however, and Mike Sangster and Roger Taylor doled out some punishment of their own – Taylor winning 6-2, 6-1, 6-0 – as GB whitewashed their hosts.

Don’t hold your breath for Rafael Nadal and Andy Murray turning out in La Liga or the Scottish Premiership, but they show that ball skills can be transferable.

Fruity footballers

“Cameroon’s Yaya Banana scored against Guinea-Bissau at the Africa Cup of Nations. Are there any other players with fruit as their name or surname?” asks Bogdan Kotarlic.

Chris Page starts off a trio of cherries with former England defender Trevor. “I also offer up several other historical examples: Rushden & Diamonds winger Tyrone Berry, Raleigh Flyers midfielder Chris Apple, York City goalkeeper Jeff Pears, Cardiff City midfielder Steve Grapes.

“Journeyman goalkeeper Steve Cherry springs to mind,” offers Tom Aldous. “I also checked to see if there were players with the surname Oliva (Spanish for olive) and it turns out there are Aythami Artiles Oliva, Carlos Oliva and Maximiliano Oliva.”

Tim Postins brings up the jackpot with Paul Cherry, the former St Johnstone and Inverness Caledonian Thistle midfielder, before chucking several more into the bowl: “Steve Pears was at Middlesbrough from 1985 to 1995, Seth Plum played for Charlton in the 1920s and, of course, the greatest haircut in British football, Wolves legend George Berry.”

Playing with your club for your country

“Richarlison, who plays for Everton, was in Brazil’s squad as they won the Copa América, where an international teammate was called Everton,” writes Doug McNair. “Are there any other examples of players having international teammates sharing their name with their club?”

“Look no further than Brazil in the last Copa América (the fake one in 2016),” writes Tim Dockery. “Douglas Santos (then of Atlético Mineiro) was in the Brazilian squad alongside Lucas Lima and Gabriel, who both played for Santos.”

“Flavio Roma played three games for Italy in 2005,” adds Tom Aldous. “His teammates included Roma player Daniele De Rossi.” Meanwhile, Alex Partenopei observes this from Italia 90: “Italy and Napoli defender Ciro Ferrara had a teammate named Fernando De Napoli … who also played for Napoli.”

Rich Jones offers this from Euro 2008: “Milan Baros was in the Czech Republic side, alongside Milan defender Marek Jankulovski.” There’s an England example too, courtesy of Jack Blackbird: “I’ve found an example from USA 0-10 England in 1964. Charlton’s Mike Bailey played alongside Bobby Charlton that day, who came on as a substitute and scored.”

Knowledge archive

“Is it really true that a Romanian side once built a moat filled with crocodiles to stop the crowd from invading the pitch?” wondered Ben Evans in 2006.

Incredibly, Ben, this snappy piece of hooligan deterrence actually was planned. Back in 2003, fourth-division Steaua Nicolae Balcescu found themselves in a quandary: Romanian leagues chiefs were threatening the club with expulsion following a series of pitch invasions and violent outbreaks. What was the club to do? Perimeter fencing? Increased stewarding? Not quite.

Chairman Alexandra Cringus came up with the “innovative” concept of creating a moat surrounding the pitch, packed with fully-grown crocodiles. “This is not a joke,” insisted Cringus. “We can get crocodiles easy enough and feed them on meat from the local abattoir. The ditch is planned to be wide enough that no one could manage to jump over it. Anyone who attempted to do so would have to deal with the crocs. I think that the problem of fans running on to the pitch will be solved once and for all.” You don’t say.

And what of players tumbling off the field? Cringus planned to create the moat far enough from the pitch to prevent said calamity, yet not forgetting about the crocs; electric pipes were to be installed to keep the water heated during cold weather. The last we heard was that local authorities were considering the proposal.

• For thousands more questions and answers look through our archive.

Can you help?

“Now that Frank Lampard is Chelsea manager, what other current examples are there, club or country, of a team being managed by their all-time top goalscorer?” asks Masai Graham.

“I happened to notice Laurent Blanc is Montpellier’s top goalscorer with 84,” begins Michael Bond. “Given that they have been established for 100 years, it seems surprising that no striker has bested this. Are there any other clubs with a similarly long histories who have defenders as record scorers?”

“Last week QPR sold Matt Smith to Millwall and signed another Matt Smith on loan from Manchester City … on the same day,” writes Martyn Bryce. “Do readers have other examples of such dealings with players of the same name.”

• Email your questions and answers to knowledge@theguardian.com or tweet @TheKnowledge_GU.