Apple has teamed up with some of the sports world’s most notable professional athletes in order to test the upcoming “iWatch’s” fitness capabilities in intense training environments, according to a source with knowledge of the testing. This source says that Apple has invited athletes from the MLB, NHL, and NBA to its Cupertino-based campus on multiple occasions over the past several weeks to brief the players on the upcoming wearable device and provide an opportunity for testing to be conducted in professional conditioning environments.

Apple is said to be working with Los Angeles Lakers basketball player Kobe Bryant, Los Angeles Kings right winger Dustin Brown, and a few other star athletes, including a player from the Boston Red Sox, on the testing project. The athletes are said to have signed non-disclosure-agreements regarding the existence of the upcoming Apple wearable device. Nonetheless, Bryant was spotted at Apple’s campus last month meeting with Apple design chief Jony Ive. Indeed, the meeting between the pair is said to have been in regards to “iWatch” testing…

The testing of the Apple wearable device in fitness environments further indicates that the device will have significant fitness components. Combined with HealthKit in iOS 8, the Apple hardware will likely be capable of tracking steps taken, calories burned, and heart rate. Additionally, Apple has been working on advanced sensors to read a person’s hydration levels, blood pressure, and sweat, and those three components of the body could assist professional athletes during their training exercises.

Apple, last year, hired former Nike fitness consultant Jay Blahnik to work on the smart watch project, and he is likely working with these athletes on the testing. As Nike winds down its work on FuelBand hardware, Apple has hired at least a few mechanical engineers that worked on Nike’s wearable devices. Apple is said to have also created a small team dedicated to testing the upcoming fitness band specifically in health and fitness environments. A job listing from earlier this year indicated Apple was seeking engineers to test fitness-related initiatives.

Additionally, Apple has created a team under medical executive Dr. Michael O’Reilly with sleep, health, and sensors experts to work with government regulators and engineers on approving and testing upcoming wearable computers. A report from earlier today claimed that Apple is still seeking FDA approval for the upcoming wearable hardware, and Apple and the government division have met multiple times in regards to medical products over the past few years. As former government affairs chief at Masimo, Dr. O’Reilly had success working with governments, so it is likely that Apple is progressing with its regulation talks.

The Wall Street Journal reported earlier today that the device is expected to include 10 sensors, and Apple’s hiring strategy over the past two years sheds some light into which sensors the device will likely pack. In the summer of 2013, Apple assembled a team of sensor technology experts under the guide of Dr. Todd Whitehurst, a former hardware executive from firm Senseonics who specializes in micro-sized sensors capable of non-invasively analyzing a person’s blood glucose levels. Apple has also hired several employees from now-defunct technology company C8 Medisensors, which also specialized in blood reading.

Later in 2013, Apple hired Nancy Dougherty from stealth medical startup Sano Intelligence, and Dougherty has extensive experience in designing small sensors for reading bodily information such as glucose and potassium levels. Apple also hired Ravi Narasimhan last year from Vital Connect, a company producing technology that can measure steps, skin temperature, respiratory rate. The Cupertino-company also recently brought sleep analysis scientist Roy Raymann from Phillips and rising medical product star Divya Nag into the fold. All of these experts have contributed to both the Health software in iOS 8 and the preparations for the launch of the upcoming Apple wearable hardware.

Besides being a fitness device, the “iWatch” will be positioned as a fashion accessory, according to the source with knowledge of the device’s testing with celebrity athletes. The Jony Ive-designed product will feature an elegant design and a display that a report yesterday explained as slightly rectangular. The source also noted that the device, as other have reported, is expected to come in two distinct variations. Another source said that former Yves St. Laurent CEO Paul Deneve, now a vice president at Apple reporting to Tim Cook, has been creating strategies for selling fashion products in Apple’s stores. Former Burberry CEO and now Senior VP of Apple Retail Angela Ahrendts is also likely involved in preparations for marketing the future Apple wearable device.

It is unclear if Apple will leverage these testing partnerships with athletes for future marketing strategies or sponsorship deals for the fitness product. Bryant is a current Nike partner, and with Apple working closely with Nike on fitness functionality, a marketing deal with Bryant seems like a natural fit.

In addition to fitness, health-tracking, and fashion components, sources say that the smart watch will run a variation of iOS and include advanced maps functionality. The device has been rumored to include a screen with a size between 1.5-inches and 2.5-inches, and this will provide room for Apple to include a usable version of iOS for the product. iOS 8, running on the iPhone and iPad, includes technologies fit for a smaller device such as widget applications, more intuitive messaging, and the ability for devices to be more easily paired. A source says that the watch will be heavily reliant on the iPhone and will be designed to share an internet connection with the smartphone.

The Apple smart watch is currently on track to be introduced at an event in October, and with the device moving into mass production within the next two months, the product will likely ship within a few weeks of its introduction. Apple is also planning a line of larger-screened iPhones, faster iPads, new Mac computers, and new iOS 8 and OS X Yosemite operating systems for release in the fall. Apple CEO Tim Cook previously teased “big plans” from Apple for 2014, and Apple Senior VP Eddy Cue said that Apple’s fall 2014 product pipeline is the “best” he has seen in his 25 years at Apple.

FTC: We use income earning auto affiliate links. More.

Check out 9to5Mac on YouTube for more Apple news: