Over the last decades, physical inactivity has reached pandemic proportions worldwide, and therefore became a public health priority. Despite its importance, there was no observatory dedicated exclusively to monitor physical activity surveillance, research and policy worldwide. In 2012, The Lancet Physical Activity Observatory was launched in response to this urgent call for action.

Purpose: To describe the work conducted by The Lancet Physical Activity Observatory in order to track physical activity surveillance, research and policy worldwide.

Methods: The Observatory has a website, directed and managed by physical activity epidemiologists and public health researchers. The main Observatory’s product are the country cards, which are country profiles from 219 countries that include general country data in addition to common surveillance, policy and research indicators. All the information was gathered using a standardized methodology.

Results: The Observatory will be able to reach local experts in 219 countries and therefore create a global collaborative network to monitor physical activity. Each of the countries will have a page in the website that will include local data, contact information and the translated card. The country cards will help countries to determine which are their needs and opportunities to initiate or improve standardized data collection, surveillance systems, policy making, program development and evaluation in the area of physical activity.

Conclusion: The Observatory’s expectation is that these country cards become an evaluation and advocacy tool helping governments, researchers and society to improve their health status through physical activity.

In this paper, we review the general mechanisms of accelerometer-based activity monitors and validation studies of the activity monitors commonly used in Japan. We also summarize intervention studies aiming to promote physical activity by using activity monitors as motivational tools and discuss future research implications in this field. Activity monitors generally house an accelerometer, internal clock, analog/digital converter, processor, data storage, and battery. Activity monitors vary greatly depending on their sensor properties, filtering process, summarization by epoch, and conversion from acceleration signals to activity outputs. In addition to hip-worn monitors, wrist-, ankle-, and thigh-worn monitors have become increasingly common in recent years. A few representative Japanese activity monitors have already been validated against doubly labeled water and Douglas bag methods under field and laboratory settings, respectively. Future research should use sophisticated statistical models to discriminate posture allocations and activity classifications in individuals with various lifestyles. At present, there is a lack of quality intervention studies using activity monitors. Considering the rapid dissemination of consumer activity monitors, intervention studies designed to promote physically active lifestyles by using activity monitors would be novel and significant.

Objective: We used a behavior recording method to develop a self-reported physical activity measurement system. The purpose of this study was to compare the results from this system against objective data provided by a 3-axis accelerometer, so as to understand the strengths and weaknesses of the new measurement system.

Methods: A total of 75 subjects (20–22 years of age) participated. The subjects entered behavior data using their personal computers just before bedtime for 7 days, which delivered intensity data to a web server every 15 minutes. Subjects also wore a 3-axis accelerometer over the same days. The three measures of intensity were: total energy expenditure (TEE), activity-related energy expenditure (AEE), and physical activity level (PAL).

Results: The Pearson correlations for TEE, AEE, and PAL between the two methods were all positive and significant: r=0.875 (p<0.01), r=0.773 (p<0.01), and r=0.715 (p<0.01). Time comparisons for each type of intensity data of the system compared to the 3-axis accelerometer showed an overestimate above 3 METs, while there was an underestimate in the range of 1.6-2.9 METs. Correlation of the time for each type of intensity data of the system compared to the 3-axis accelerometer was r=0.495 (p<0.01) above 3 METs, while there was no significant correlation in the range of 1.6-2.9 METs and over 4 METs.

Conclusion: The physical activity measurement system produces data of high overall validity, although users of this system should note that the accuracy of the system at various levels of intensity requires further study.

Objective: The purpose of this study was to describe the prevalence of shoulder pain in Japanese badminton players.

Methods: The participants of this study were Japanese badminton players on school-sponsored badminton teams. From October to December in 2011, a questionnaire on shoulder pain was distributed to 1410 players in 15 junior high schools, 23 high schools, and 16 colleges in the Kanto region. A valid response was received from 1002 players (202 in junior high school, 411 in high school, and 389 in college) and the response rate was 71.0%. The questionnaire items were about history of shoulder pain, recent shoulder pain (in the past year), and interference with playing badminton.

Results: Of those surveyed, 53.3% (58.4% in junior high school, 38.2% in high school, and 66.6% in college) reported a history of shoulder pain. Among those with a history of shoulder pain, 46.0% (50.5% in junior high school, 32.6% in high school, and 57.8% in college) suffered shoulder pain in the past year. Interference with playing badminton was reported in 48.4% (41.2% in junior high school, 50.0% in high school, and 50.7% in college).

Conclusions: The present study suggests that almost half of Japanese badminton players have a history of shoulder pain and the prevalence differs depending on age (junior high school, high school, and college). The study also suggests that almost half the players with shoulder pain in the past year have had interference with playing badminton. Prevention strategies for shoulder pain in badminton players should be developed based on descriptive epidemiology.

It is important to consolidate existing evidence, facilitate international comparisons and encourage more evidence-informed physical activity and health policies for the promotion of physical activity in children and youth. It is also essential that researchers share their information with not only other researchers but also teachers, coaches, policymakers, and the wider public. The “Active Healthy Kids Report Card” is structured with 9 common indicators which identify the state of physical activity in children and youth in each country and factors influencing their physical activity. Since the first “Active Healthy Kids Canada Report Card” was released in 2005, it has been reporting on 15 countries, including low, middle and high income countries, forming the “Active Healthy Kids Global Alliance” (www.activehealthykids.org). An international report card will be released on >40 countries with broad geographic and income variation at the 6th International Congress on Physical Activity and Public Health in 2016 in Bangkok. The “Active Healthy Kids Japan Report Card” is now being developed by a working group. This paper summarizes the contents of The “Active Healthy Kids Report Card,” the processes used to develop the card, and the results of an international comparison among 15 countries.