Stride frequency and respiratory responses during running

The purpose of this study was to investigate the influence of varying stride frequency on the respiratory responses during 6-rnin bouts of treadrnill running at a fixed speed (150 rneters .min-1). Five rnales and five fernales participated in the study who had no experience on long distance running training. All the subjects cornpleted in a total of five runs involving the freely chosen normal stride frequency，±10%and ±20% from the norrnal stride fre- The results were as follows: 1. With decreasing stride frequency (SF) frorn 160 strides ・min-1，respiratory frequency (f) extremely increased. On the other hand with increasing SF frorn 160 strides .miin-1，f progressively increased. 2. Although fs howed ac lear entrainrnent to SF，the coupling ratio (SF: f) shifted frorn nearly 2: 1 t o 4: 1. 3. The ventilatory efficiency decreased with increasing f. It was due to the ventilatory equivalent for oxygen uptake (V E/V O2) increased with increasing f. The findings of this study suggest that SF has sorne regulatory role in the control of respiration during rhythrnical running at a low intensity