Tennis star Rafael Nadal has spent these past few days training hard on the hard court under scorching hot temperature in his hometown in Mallorca.

The 27-year old Nadal will be making his return in the US hard court scene following his sensational victory at Indian Wells earlier this year.

Nadal recently suffered his first defeat in the first-round of a Grand Slam tournament after succumbing to Steve Darcis in three sets on the opening day of competition at All-England Club.

However, the Spanish matador remains optimistic about his chances in the upcoming hard-court season. Over the past couple of weeks, Nadal posted several pictures on his Twitter account, showing him in the middle of intense training off and on court.

Nadal has always been a hard worker no matter what kind of surface he will be competing on next. But several tennis experts are worried about the health of these players as they believe the punishment of playing on the hard court will eventually take the tool on their body.

"The pounding their bodies take, with all the jarring and wrenching of knee joints, ankles and hips is pretty horrific, especially on hard courts. They are the worst," a former British Davis Cup champion told Tennis Earth.

Moreover, BBC commentator John Alexander even considered the hard court as a health risk for players and he won't be surprised if they will eventually sue the ATP Tour for fielding multiple tournaments in such tough condition.

It's no secret Nadal is doing all the necessary things to keep his left knee damage-free as possible without holding off his competitive attitude on the court.

After missing the hard-court season last year, Nadal is back to assert his presence on this surface, no matter how risky it is. For the Spaniard, there's one big mission that keeps him driven - and that's another Grand Slam crown in Flushing Meadows next month.

Entrenando en #Mallorca con mucho calor. Practising in #Mallorca. It's very hot! pic.twitter.com/CHfSRP8CH8

- Rafa Nadal (@RafaelNadal) July 26, 2013