Physical activity is essential in all life stages because it maintains and improves a person’s vitality, protects them from diseases and improves the quality of their lives. Physical inactivity has a great impact on a person and their health since it is the fourth leading risk factor for global mortality. Despite the known benefits of physical activity people in many countries around the world are not physically active enough, according to the World Health Organization. This data is, in many countries including Slovenia, usually collected through questionnaires based on self-report method. This is the simplest way of collecting a large amount of information though it has many limitations and a low validity. Consequently, more objective measuring methods, providing better and more accurate measuring of an individual’s and population’s physical activity, should be searched for.
The purpose of the thesis was to study the validity of a fitness tracker. The Fitbit Charge HR (Fitbit Inc., San Francisco, CA) fitness tracker was used in the research. It was compared to the research accelerometer UKK RM42 (UKK Terveyspalvelut Oy, Tampere, Finland). 58 people tested wore the devices 6 or 7 days, 24 hours a day, except when taking shower or during other water activities. In the analysis the data of 53 participants was used and processed using two programs: the IBM SPSS Statistics 22 (SPSS Inc., Chicago, USA) and Microsoft Excel (2013 version, Microsoft Corporation, Redmond, USA).
Pearson’s correlation coefficient was calculated. We found that there is a moderately positive correlation (0,64) between the two devices when measuring the average daily step number. We also found that the strongest positive correlation between the two devices is in the group of individuals with the BMI higher than 30. There is also the most significant difference in the number of daily steps and thus the highest percent error.
The results of our study are a contribution to the consideration of a more objective measurement of a population’s physical activity. The results are in accordance with the previous studies and show that fitness trackers have a higher validity than questionnaires. We believe that it would be advisable to consider the use of fitness trackers for a potential monitoring of a population’s physical activity. We are, nevertheless, aware of the disadvantages that the use of fitness trackers could bring.