Strides = a full left foot + right foot step. So LR = 1 stride. LRLRLR = 3 strides.
You can hear these audibly pretty easily, as left and right foot steps have distinct pitches.

It takes 9 strides of walking (full steps as noted above) to recover your full sprint stamina (9 walking strides takes ~7 seconds, about 30% of your melee stamina bar will refill). With full sprint stamina, you get 53 strides of sprinting.

With greyhound, you get 106 strides of sprinting instead of 53 (double). It still takes 9 strides of walking for full sprint stamina recovery.

With determination, it only takes 7 strides of walking instead of 9 for full sprint stamina recovery.

With less than 5 strides of walking (about 4 seconds), you get zero sprint stamina recovery. This is because your sprint stamina and melee stamina begin recovering at the same time (about 4 strides).
5 strides walking --> 10 strides of sprint
6 strides walking --> 21 strides of sprint

So the most efficient overall speed is to take 9 strides walking for 53 strides of sprint as described above. If you count from when your melee stamina starts recovering, it's about 5 strides or when the melee stamina gains about 30% of the full bar.

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