The rumors about Apple Inc. (NASDAQ:AAPL)’s supposed iWatch just keep coming in. This time, there’s a patent that suggests a possible functionality that hasn’t been speculated about yet. On Tuesday, the U.S. Patent and Trademark Office issued Apple a patent for a system that tracks weightlifting activities using a special sensor.

Apple iWatch

Apple’s iWatch and HealthKit

Apple Insider spotted the patent for something called a “Shoe wear-out sensor, body-bar sensing system, unitless activity assessment and associated methods.” The patent application cites a long list of previous patents, all of which describe an ecosystem that revolves around fitness. The system would certainly fit in with the HealthKit API Apple Inc. (NASDAQ:AAPL) unveiled along with iOS 8 at its annual Worldwide Developers’ Conference (WWDC) last week.

Throughout the years during which these health-related patents were developed, Apple Inc. (NASDAQ:AAPL) has mostly removed the references to sensors that track show wear-out and unitless measurements. However, the company has left in the “body-bar sensing system,” along with the readout that’s meant for a watch.

How the iWatch patent might work

This newest patent describes a system that enables a device that’s equipped with sensors to attach itself to a weightlifting bar. The system then counts repetitions and displays them to the user. Apple Inc. (NASDAQ:AAPL) itself has added the use of a watch to offer remote readings. This seems to suggest that the system could have a future in the rumored iWatch.

The device that attaches to the weightlifting bar could have a number of accelerometers, Hall Sensors, processors and a display. The watch would then calculate the numbers and display the user’s progress wirelessly. Apple Inc. (NASDAQ:AAPL) describes the device that attaches to the weightlifting bar as either a portable unit that can be moved to each piece of exercise equipment as the user moves through the gum. The company also includes a more permanent version of the device that’s attached to the weightlifting bar using a clamp and stays with the equipment.

What the system might show

Throughout the user’s workout, they can view numerous metrics through a watch, including the amount of time between each movement. The watch can then compare these metrics with previous recorded metrics to show the user how much progress they are making.