(CNN) Swarms of drones follow you while you run, recording video of your workout. Sensors hidden in your T-shirt track your heart rate and how many calories you're burning. Your sunglasses log your miles and respond when you ask, "How's my pace?"

No, you and those sci-fi gadgets aren't starring in the next action-packed Marvel flick. Rather, those gadgets might be the future of fitness trackers, according to sports technology experts.

As wrist-worn wearables phase out, less invasive and more personalized devices may phase in, said Gina Lee, founder of the Legacy Sports Institute , a health-care facility for professional and amateur athletes slated to open in Alpharetta, Georgia, by the end of the year.

"The future of technology is definitely to develop the most invisible, smallest, least detectable technology for consumers that can track the most biometric data and be consumer-friendly and have accurate outcomes," Lee said.

Here's a look at how fitness technology of the future may become more hidden, more like a coach and more personalized than ever before.

It's about preventing injury, too

"I see the emerging trend of technology becoming more and more invisible," said Mounir Zok, director of technology and innovation for the US Olympic Committee.

Wearable technologies that track your physical activity, heart rate and sleep patterns are now being designed into clothing, Zok said.

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Now, there are smart socks, such those by Sensoria , and shoe inserts, such as those by Digitsole , that can do the same but also track cadence and foot landing technique.

There are smart accessories, like a ring by the personal technology company Motiv and a sports bra by the bio-sensing clothing company Omsignal , that can discreetly track your heart rate and physical activity.

"Think of the textiles taking on the electronics by picking up data points from athletes, rather than having rigid wearable technology solutions on a wrist or on the chest," Zok said. So, "athletes would be wearing a sleeve, or would be wearing just a compression shirt, and integrated inside the shirt would be the sensors."

Smart clothing could revolutionize not only fitness but injury prevention and physical therapy, said Dr. Jiten Chhabra, a physician and research scientist at the Interactive Media Technology Center at the Georgia Institute of Technology.

"The thing that I am most excited about, probably because of my medical background, is the prevention and early detection of injury," Chhabra said. "This kind of physiological surveillance is now part and parcel of the highly personalized training regimens that are enabled by sports wearables."

For instance, biosensors could detect unusual muscle contractions or abnormal heart rate or respiration patterns. That data, if presented to a doctor, could hold many clues to your health, said Chhabra, himself a swimmer who wears a Moov motion tracker around his wrist to track his laps.

Some fitness technologies are being used and developed to help remind physical therapy patients to perform rehab exercises at home and to guide patients through those exercises, said the Legacy Sports Institute's Lee.

"It's great, as a physical therapist, to be able to know that there's reminders of what's so important in order for them to achieve their rehab goals," she said, adding that fitness trackers can help patients and their doctors to monitor and assess recovery from injury, too.

Indeed, fitness technology of the future could play more of a coaching role.

A hidden downside of fitness technology

There are many new fitness devices on the market that can provide real-time feedback and guidance to users during a workout.

The Lumo Run , a small sensor that clips onto your clothes, can connect to and speak through your iPhone to deliver real-time feedback as you run and move.

The sports technology company ShotTracker has designed a sensor that fits into a sleeve or wristband to track shooting stats for basketball players but also offer feedback on how to improve shooting.

For runners and cyclists, the sports equipment company Oakley has designed glasses, called Radar Pace , with built-in headphones that allow the user to hear an automated coach share info about their training regimen, miles logged and pace.

"I do like that there is a connectivity component," Lee said. However, that extra feedback or voice in an athlete's ear could be harmful for some athletes and their mental health, she added.

"The technology can be an added stress to some individuals, if you are already a goal-driven person, an athlete, and you don't meet those goals that your technology has been set up for," Lee said.

"Those types of things can lead to a person feeling depressed or like they failed, which leads to anxiety, and that would be very detrimental to an athlete's performance," she said.

In order to turn a computer into an effective coach, algorithms would have to become more personalized, said the US Olympic Committee's Zok.

"When you observe athletes and coaches working, you rarely observe a conversation based around what is the exact number of joules, what's the exact number of calories or exact number of steps that they just went through," Zok said.

"Rather, you hear coaches telling athletes that we can push more, or we need to push less, or we can go faster, or let's take it slow today," he said, indicating that each athlete requires a different type of coaching.

"Once you deliver to two different athletes, two different messages based on the same data point, then that technology becomes a humanized technology," he said.

'A world that is observing you'

Next, Zok said, this personalized element could even be integrated into homes of the future.

"A connected gym or a connected house would be an environment that is able to extract data points from my activity without me having to take any specific actions to do that," Zok said.

For instance, your home could be programmed to track your sleeping patterns and then automatically adjust the thermostat and lighting to when you wake and when you sleep, he said.

"The connected world is a world that is observing you, that is monitoring you, that is interacting with you, so that you can meet your objectives and your goals in the most effective fashion possible," Zok said.

"In the future, I want to live in a connected house as an athlete. I want to train in a connected venue. I want to work out in a connected gym," he said. "As I'm going about my life, let's say, spending time with family and friends or just traveling, I want to be wearing connected clothes."

Yet, there are privacy concerns when it comes to connected devices. Sure, you would want your fitness tracker and your connected house to collect health data for your benefit, but such devices have the potential to be hacked and collect other data, such as by recording private conversations.

"A big limitation is that continuous or periodic data streams bring with them the problems of security, privacy and clutter," said Chhabra, the research scientist at Georgia Tech. "This is not health-specific but the stakes are much higher in healthcare."

For technologies to be connected with your daily life, however, how would data be collected to help program the technologies and make them more personalized? Zok pointed to drones.

"I can have them in my backpack, and as soon as I open up my backpack, I'll tell my drones to set themselves to running mode and so I would start doing my running, and the drones would be following me and getting the footage from me without me even touching them," Zok said, describing how drones could collect video data in the future.

"If you want to imagine the athletes of the future, you can imagine maybe each one of them running with a swarm of small drones around them," he said.

But as such new fitness devices emerge, they could come with a hefty price tag.

Finding the right device, at the right cost

For an athlete training to win, the cost can be worth it, said the Legacy Sports Institute's Lee. It's just a matter of finding the right device for the right goal.

After all, a 2014 report from the UK-based market research group Juniper Research projected not only that fitness wearables will remain popular but that the use of fitness wearables will increase nearly threefold by next year.

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Training for a marathon? "You want to make sure that's something that can track your heart rate, your work load, your pace, the calories burned so you know you're getting the right hydration and nutrition," Lee said.

Need to lose weight? "We want to make sure that you have a trackable device that can calculate the calories burned. That's the big focus with weight loss: making sure we're burning enough calories to lose the pounds," she said.

For professional athletes in particular, "they are always looking for any technology that can help make them be the best athlete they can be," Lee said. "If it is something that can really enhance the performance level of an athlete, if it is viable for an athlete to be able to afford, they will spend the dollar to be able to meet their peak performance."