While most people appreciate the importance of physical fitness, many have difficulty finding the motivation required to maintain a regular exercise program.  Some people find it particularly difficult to maintain an exercise regimen that involves continuously repetitive motions, such as running, walking and bicycling. 
Additionally, individuals may view exercise as work or a chore and thus, separate it from enjoyable aspects of their daily lives.  Often, this clear separation between athletic activity and other activities reduces the amount of motivation that an individual might have toward exercising.  Further, athletic activity services and systems directed toward encouraging individuals to engage in athletic activities might also be too focused on one or more particular activities while an individual's interest are ignored.  This may further decrease a user's interest in participating in athletic activities or using athletic activity services and systems. 
Many existing services and devices fail to provide accurate assessment of the user's energy expenditure, such as caloric burn, during physical activity.  Therefore, users are unaware of the benefits that certain activities, which may include daily routines that are often not thought of as being a “workout”, are to their health.  Existing devices for allowing users to monitor their energy expenditure often suffer from one or more deficiencies, including: cumbersome collection systems, inaccurate measurements that are beyond an acceptable threshold, unacceptable latency in reporting the values, erroneous classification of activities based upon detected motions of the user, failure to account for deviations between different users, improperly including repetitive behavior as being classified as a specific activity, such as for example, running and/or walking, relatively high power consumption, and/or a combination of these or other deficiencies. 
Therefore, improved systems and methods to address at least one or more of these shortcomings in the art are desired.