Andy Murray will undergo sweat testing in a last-ditch bid to resolve his cramping concerns ahead of the US Open, which begins on Monday.
The 2012 US Open champion, who is ranked No 47, will be unseeded going into this year's tournament and has drawn 24th seed Francisco Cerundolo from Argentina in the opening round.
Murray has overcome hip, back and knee injuries in recent years, while his hopes of reaching the second week of a Grand Slam for the first time since 2017 appear slim having suffered bouts of cramp since landing in the United States in mid-July.
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"From the physical side it's been a bit frustrating right now because I've been pulling up from the matches really well in terms of where my body is today in comparison to last year, for example. I'm in a much better place in terms of how my left groin has been and my lower back - it's been really good," the 35-year-old said.
"There's been no need for me to take anti-inflammatories for matches and tournaments and stuff which hasn't been the case much for the last few years so that's been really positive but then at the same time I've had the cramping.
"Since I've been over here I've been lucky in some of the matches, like against [Stan] Wawrinka I was lucky to get through that one.
"Against Mikael [Ymer] in Washington it was not good because I could barely play in the third set and obviously what happened in the match against Cam [Norrie] in Cincinnati.
"Physically I feel pretty good in terms of discomfort and pain and everything but then I've been having the cramping the last few weeks so that's been frustrating.
"I've had cramp before but not consistently so I'm just trying to understand and get to the bottom of that."
Murray and his team hope to resolve the issue of why the cramping keeps occurring with his hydration, conditioning, stress and diet all under the microscope.
He explained: "I'm doing sweat testing in these conditions to see if anything has changed in that respect because the sports drinks and the electrolytes is made specifically on my sweat tests, but I haven't done sweat testing for quite a number of years.
"I don't know if anything has changed in that respect but we'll try and get to the bottom of it, because let's say if it was purely from hydration, then obviously after I got cramp like in Washington I made sure that I was not dehydrated going into the next matches. And if it was eating related then I made sure all of those boxes were ticked.
"It's not just been as simple as changing how much I've been drinking or what I'm drinking so I need to get some answers."
Murray believes his game has not been consistent enough this year with the former world No 1 having failed to pick up a an ATP title for the first time since 2019, despite reaching finals in Sydney and Stuttgart.
His form on the American hardcourts doesn't bode well for his chances heading into the US Open where he will come up against Bastad winner Cerundolo before a potential date with Australian veteran John Millman and then what could be a blockbuster clash former Wimbledon finalist Matteo Berrettini further down the line.
"From the tennis side of things I've had some good wins and some tough losses. It's not quite happened at one of the big events yet, so that's been disappointing," he said.
"It's just not been consistent enough and consistency is what matters over the course of the year. You can do it for the odd match or two but if it's not the same for large parts of the year then you're not going to win as many of those matches you would like."
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Murray also believes this year's Grand Slam is the "most open" it has been in years, saying: "I would imagine some of the guys who you would expect to go deep, will do. [Daniil] Medvedev, Rafa [Nadal], [Carlos] Alcaraz and [Stefanos] Tsitsipas - these guys.
"I do think there will be an opportunity for Cam [Norrie]. He's been very consistent against the guys ranked beneath him for the most part this year. He's definitely got a chance of a good run. When it's hot and humid that can help his game and the courts here are quite fast.
"Certainly the heat and the humidity is a positive for him."
Andy Murray is wearing The Drive Collection from his signature AMC range during this year's US Open, created to deliver a new standard in tennis performance clothing. View the kit at www.castore.com/collections/amc.