1. A method for guiding a user to a target rhythmic MSKC to CC timing relationship comprising: detecting a first signal responsive to the timing of the CC of a user using a first sensor; determining the heart rate of the user using at least a portion of the first signal detected by the first sensor using a first processor; providing a recurrent prompt from a prompt device to the user as a timing indication for performance of a rhythmic musculoskeletal activity, wherein the timing indication guides the user to a musculoskeletal activity cycle rate (MSKR), wherein the heart rate of the user is substantially an integer multiple of the MSKR; detecting a second signal responsive to the rhythmic musculoskeletal activity timing of the user that repeats at an MSKR of the user using a second sensor; determining an actual MSKC to CC timing relationship between the first signal and the second signal using the first processor; comparing the actual timing relationship of the first signal and the second signal to a target MSKC to CC timing relationship, wherein the target timing relationship is provided by the first processor or a second processor; and adjusting the timing indication of the recurrent prompt from the prompt device to the user based on a difference between the actual timing relationship and the target timing relationship, so as to reduce the magnitude of the difference.