目的：在於分析受試者100公尺跑各段落加速期、高速期、維持期、減速期之步幅、步頻和平均速度之變化，瞭解短跑選手全程跑速度表現的能力，並進一步探討步幅、步頻與平均速度之相關，提供給教練及選手瞭解何者對速度表現較為重要，以作為訓練時的參考。方法：本研究對象為短距離項目選手共20人（男選手N=12人，女選手N=8人），以攝影機拍攝選手100公尺全程跑，擷取影像資料（速度為60張∕秒），計算每10公尺分段時間、分段步幅和分段步頻，以描述統計和Pearson積差相關，考驗步幅、步頻與平均速度之相關程度。結果：女選手和男選手全程最高速度皆在50-60公尺段落；最高步頻產生分別在加速期的20-30公尺段落和高速期的30-40公尺段落，在高速期後，步頻則呈現些微的遞減狀態，尤其在減速期90-100公尺段落處步頻下降幅度最大。而步幅則在起跑後的加速階段不斷的增大，女選手約在40-50公尺段落處產生最大步幅，男選手則在50-60公尺段落漸增至次大值，產生第一個步幅峰值，之後的步幅雖有小幅度下降，但到減速期90-100公尺段落，由於步頻頻率的遞減，而導致速度有下降的趨勢，因而以增大步幅維持速度，於是在減速期出現第二個步幅峰值。由此得知，百公尺的加速階段是步幅、步頻同時增大的結果，而百公尺後段速度降低主要因素為步頻頻率的遞減所引起，全程高速度的保持則由步幅和步頻互補所得。結論：本研究認為步幅、步頻與平均速度之相關，研究結果步頻與平均速度有較高的相關性，而步幅次之；顯示100公尺成績取決於運動選手最大的速度能力，然而在速度的表現中，步頻與平均速度的相關性較高，可以說明步頻是影響百公尺速度的重要因素。

This study investigated the changes of the stride length, the stride frequency, and the average speed during accelerating, high-speed, maintaining and decelerating periods of the 100m sprint. The speeding performance was explored, and the relationships among these parameters were further investigated for generating useful information for coaches and athletes in training. Twenty sprint athletes were recruited in this study (20 males and 8 females). The whole course of the 100m sprint was photographed by the camera (60 frames/min), and the time period, phase average stride length, and phase average stride frequency were computed every the 10 meters. Collected data, including the stride length, the stride frequency, and the average speeds, were analyzed by the descriptive statistics and the Pearson product moment correlation. It was found that first, both female and male players reached their high-speed period at 50-60m. Second, the highest stride frequency occurred at 20-30m (i.e. the accelerating period) and 30-40m (i.e. the high-speed period). The stride frequency declined gradually after the high-speed period, especially with a biggest downfall at 90-100m (i.e. the decelerating period). Third, the stride length started to increase continuously from the accelerating period. Female athletes got the biggest stride length at 40-50m, while male athletes reached the peak stride length at 50-60m. Although the step length decreased slightly afterwards, the stride frequency went down in the decelerating period at 90-100m, and resulted in a downward speed. In order to maintain the high speed, the athletes adopted a bigger stride length, and hence got the second stride length peak at the decelerating period. Therefore, the 100m acceleration resulted from increases of the stride length and frequency, while deceleration was due to the decreases of the stride frequency, and the high speed of the whole course came from complementation of the stride length and frequency. The correlation between the stride frequency and the average speed was higher than the stride length and the average speed. The determinant of the 100m sprint is of the high average speed, so having a high stride frequency is the key to the performance.