目的 : 探討使用手機監控年輕族群不同行走步數量對健康體適能之影響。方法：本研究招募111人為受試對象，使用自己的手機下載身體活動紀錄程式，紀錄16週每日步行數量，步行數量透過手機中的加速度計進行三軸加速度訊號變化量測，透過每日累積的活動進行統計分析，依照平日身體活動型態分為四組，分別為坐式生活組 (N = 32)、低身體活動組 (N = 28)、一般身體活動組 (N = 24)、高身體活動組 (N = 27) 比較不同行走步數量對身體質量指數、柔軟度、腹部肌肉力量/耐力、下肢爆發力及心肺耐力表現之影響。使用二因子混合設計變異數分析，觀察 16 週(前、後測)不同身體活動量(坐式生活組、低身體活動組、一般身體活動組、高身體活動組)對體適能之影響，顯著水準訂為 α = .05。結果：使用手機結合計步應用程式時前測 (5010 ± 1340 步/天) 每日步數小於後測 (7785 ± 2422 步/天)。再者，每日不同行走步數不會改善身體適能。結論：使用手機結合應用程式可以增加身體活動量，然而，身體活動量的多寡不能只依靠每日行走步數進行評估，更應該考慮行走的運動強度，才能達到改善身體適能的表現。

Purpose: The purpose of this study was to investigate the effects of different daily step counts, monitored by smartphones, on health-related physical fitness in young adults. Methods: A total of 111 participants were recruited, each using a personal smartphone activity tracking app to record daily step counts for 16 weeks. The number of steps and walking speed were measured via triaxial accelerometer signals from the phone. Participants were categorized into four groups based on their daily activity levels: sedentary (n=32), low physical activity (n=28), moderate physical activity (n=24), and high physical activity (n=27). The study compared the effects of different step counts on body mass index (BMI), flexibility, abdominal muscle strength/endurance, lower limb explosive power, and cardiorespiratory endurance. A two-way mixed-design ANOVA was used to examine the effects of 16 weeks (pre- and post-test) of varying physical activity levels on fitness, with a significance level set at α=.05. Results: The step count from the pre-test (5010±1340 steps/day) was lower than that of the post-test (7785±2422 steps/day). However, different daily step counts did not lead to significant improvements in physical fitness. Conclusions: While smartphone apps can increase physical activity, evaluating physical fitness improvements should not rely solely on daily step counts. The intensity of walking must also be considered to achieve meaningful improvements in physical fitness.