Keep the knees and heels together. The traditional way of playing pedals is to keep the knees and heels together. In other words, both your feet should move as one unit. I understand that for some people it will be hard to do so. In this case, at least try to keep the heels together when playing pedal scales. This is necessary because we will choose the most efficient pedaling based on this technique.
Play legato. The next important point is to play with legato touch. This means that there should be no breaks between the notes. This is actually not always easy to achieve in pedal playing. I remember how hard I had to try to be able to play the notes evenly and without breaks even at a slow tempo when I was a student. It took me at least a week to master one scale. However don’t be discouraged and don’t give up. Just stick to it.
Toe-toe-heel-heel technique. The most efficient way of choosing the pedaling is to use toe-toe-heel-heel technique. This means that we play the first note with the left toe then with the right toe. The third note is played with the left heel and the fourth – with the right heel. After that just start playing with the left toe.
For example, in C major scale over 2 octaves, C would be depressed with the left toe, D – with the right toe, E – with the left heel, F – with the right heel, G – with the left toe, A – with the right toe, B – with the left heel, C – with the right heel, D – with the left toe, E – with the right toe, F – with the left heel, G – with the right heel, A – with the left toe, B – with the right toe, and C – with the right heel. Reverse the pedaling for the downward scale. Another way to play this scale is to play B with the left heel (at the end of the first octave) and start the second octave with the left toe and proceed like from the beginning.
This technique allows us to keep the heels and knees together and to play with the inside of the feet. By the way, the C major is not exactly the easiest scale to play with pedals because it lacks accidentals. Try E flat major or A major, for example and you will feel how efficient this technique is.
Adjust the pedaling when necessary. Sometimes it will be necessary to adjust the pedaling according to the accidentals because we can’t play the sharp keys with our heels. For some keys you will have to start the scale with the heel etc. In these cases, I recommend you start choosing the pedaling from the middle of the scale and then work your way downwards. For keys which have 3 consecutive sharps or flats, such as D flat major or F sharp major, you will have to slide from one sharp to another with the same toe.
Take a slow tempo, and master one major and one minor scale a week. Try to achieve a nice legato and see that all notes would sound evenly. Next week add another pair of scales (in the order of ascending number of accidentals) until in about 12 weeks you can play all of them. Then it will be sufficient to play them only once during your daily practice. If you do this regularly, your ankles will become much more flexible and you will start to notice tremendous changes in your pedal technique.
By the way, if you want to perfect your pedal technique, check out my Pedal Virtuoso Master Course - a 12 week training program designed to help you develop an unbeatable pedal technique while working only 15 minutes a day practicing pedal scales and arpeggios in all keys.