緒論：步數目標是促進身體活動的常用策略，但能否符合當前身體活動指引的建議仍有待釐清。因此，本研究以肥胖年輕成人每日累積12,000 步為目標，解析身體活動量，輕度（light physical activity, LPA）、中度（moderate physical activity, MPA）、費力（vigorous physical activity, VPA）及中度至費力身體活動（moderate to vigorous physical activity, MVPA）時間分佈百分比，以及中度至費力身體活動持續10分鐘回合數（MVPA 10 min bouts/day, MVPA_(10)）。方法：招募19名無規律運動肥胖年輕成人（平均年齡20.37 ± 1.30歲，身高167.37 ± 9.62公分，體重88.69 ± 14.95公斤，BMI 31.54 ± 3.86公斤／公尺^2），隨機分配至步數目標組（每週一至五每天皆須達成12,000步，SG組）或控制組（維持正常生活作息，CG組）。全程以穿戴式裝置（ZenWatch 3, ASUS）記錄三軸加速度值與步數。資料處理擷取有效配戴時數50小時（10小時／天），計算不同身體活動強度下時間與MVPA_(10)回合數。統計方式以曼恩－惠尼U檢定，考驗SG與CG所得參數的差異，統計水準訂為α = .05。結果：步數目標組與控制組平均步數為11,573 ± 1,007.00與8,573 ± 2,011.09步。分佈時間百分比為LPA：98.60 ± 1.35%與99.20 ± 1.31%；MPA：0.87 ± 0.72%與0.72 ± 1.22%；VPA：0.54 ± 0.71%與0.08 ± 0.11%；MVPA：1.40 ± 1.35% 與0.80 ± 1.31%。MVPA_(10)為0.30 ± 0.67與0回合。經檢定顯示步數目標組步數顯著高於控制組（p ＜ .05），而兩組LPA、MPA、VPA、MVPA及MVPA_(10)均未達顯著差異（p ＞ .05）。結論：肥胖年輕成人以累積每日步數策略反應的整體身體活動程度高於無介入組別，但仍無法達到每週250分鐘MVPA的持續時間。因此認為每日步數目標策略無法符合當前身體活動指引。

Introduction: The step goal is a strategy that often included in physical activity promotion. However, further clarification still needs to confirm whether it would in accordance with the recommendation of current physical activity guidelines. This study analyzed the percentages of physical activity volume and time distribution on LPA, MPA, VPA, MVPA, and bouts of MVPA_(10) when setting every day 12,000 steps goal for obese young adults. Methods: This study recruited 19 obese college students (age: 20.37 ± 1.30 years, height: 167.37 ± 9.62 cm, weight: 88.69 ± 14.95 kg, BMI: 31.54 ± 3.86 kg/m^2) who were not engaging in regular physical activity. Subjects randomly assigned to either step goal group (SG, achieving 12,000 steps/day on Monday to Friday) or control group (CG, maintain free-living life style). The steps and the triaxial accelerations (ACC) were monitored by a smart watch (ZenWatch 3, ASUS). The valid data were derived from 50 hours (10 hr/day) of the intervention. The time of different physical activity intensity and bouts of MVPA_(10) were further calculated. Data were analyzed by Mann-Whitney U test for examining the parameters difference between SG and CG. The significant level was set at α = .05. Results: The average steps of SG and CG were 11,573.28 ± 1,007.00 vs. 8,573.98 ± 2,011.09 steps. The percentages of each intensity were as follow, LPA: 98.60 ± 1.35% vs. 99.20 ± 1.31%; MPA: 0.87 ± 0.72% vs. 0.72 ± 1.22%; VPA: 0.54 ± 0.71% vs. 0.08 ± 0.11%; MVPA: 1.40 ± 1.35% vs. 0.80 ± 1.31% and bouts of MVPA_(10): 0.30 ± 0.67 vs. 0, respectively. The test results showed that there was a significant difference between SG and CG in daily average steps (p ＜ .05). However, no differences were found between SG and CG in LPA, MPA, VPA, MVPA and MPVA_(10) (p ＞ .05). Conclusion: Although the step goal strategy seems to produce higher volume of PA than the group without strategy group in obese young adults, the characteristics of PA still not meeting the suggestion of reaching 250 min MVPA per week. It reveals that the everyday step goal strategy is not in accordance with current physical activity guidelines.