Patent ID: 11896368
Assignee: APPLE INC.
Field: Medical technology (Instruments)
Classification: CPC A  G  H | IPC A  G  H

Claim 19:
20. A system comprising:
one or more motion sensors configured to collect motion data, the one or more sensors included in or coupled to a wearable device worn on a wrist of a user during a swimming session;
a processor circuit coupled to the one or more motion sensors and configured to execute instructions causing the processor to:
receive motion data from one or more motion sensors of the wearable device;
determine, using the motion data, a first set of rotational data of the wearable device, wherein the first set of rotational data is expressed in a first frame of reference;
convert the first set of rotational data into a second set of rotational data, wherein the second set of rotational data is expressed in a second frame of reference, and wherein the second set of rotational data includes data indicative of the user's arm or wrist movements;
determine one or more swimming metrics of the user based on the second set of rotational data, where the instructed are further executed to:
detect a number of turns and a number of strokes of the user during the swimming session based on the received motion data;

determine a number of strokes per lap based on the number of turns and the number of strokes;
determine a variance of the number of strokes per lap;
adjust the number of turns to reduce the variance of the number of strokes per lap;
determine a lap count of the user based on the adjusted number of turns; and

output the one or more swimming metrics of the user.