Back Cycling is a very important lesson on the uses of leading tones to make a stronger harmony in your chord progressions. This same contents can be used in several ways but here I will show you the most basic example of this method.
Lets start with a chord progression using C major for four measures and F Major for the fifth measure.
Understanding how harmony works with the strongest of harmonic pull we will look closely at the Dominant 7th in relation to the 1st chord or root chord. I will use colors in this example to show you how close the leading tones of the Dominant 7th chord are to the root chords quality notes. (Quality notes are the notes that give the chord it's character like Major, Minor, Minor 7th, Dominant 7th..exc...)
Here we have a C Major Barr chord on the 8th fret,
Notice the Blue notes are the root and the green note is the 3rd.
Now we will look at the 5th chord to C Major which is G Major. The 4 note quality of G major to C major is that G becomes a Dominant 7th chord which I will explain more in detail with a lesson on intervals and chord construction. The important tones or quality giving tones in the dominant 7 chord is the 'major 3rd' making it major and the 'flat 7th' making it a Dominant 7th (not a Major 7th). In this example I will display the 7th as yellow and the 3rd as red.
Now we can easily see the relation in leading tones from the 5th to the root chord.
You can see that they are only a half step away which is as close as you can get in 12 tone music. To hear the resolution better try playing the yellow and red notes and then play the blue and green. You might recognize the suspended sound it creates where it actually wants to pull or resolve to the other notes. This is harmonic movement!
Now that we have that out of the way we can get back to Back cycling.
The chord progression was C major to F major right... so to make a stronger harmony into F major you would want to use the 5th chord to F as a dominant 7th. F1-G2-A3-B4-C5! = C is the 5th chord! So just before you go into F major you want to turn the C Major chord into C7 or (C Domint 7). C7 is the shorthand for C Dominant 7th.
I do not know how to write out staff lines on here so I will just explain in text.
Play C for 4 measures of 4/4 timing. on the last 2 beats of the 4th measure change the C to C7. This will give a stronger pull towards the F Major chord that you can clearly hear.
NOW IT GETS INTERESTING!
To take this even further and make an even stronger pull to the new key lets go back a 5th to C. The 5th note from C is G. In the Key of F Major G is a minor or minor 7th chord.
So in this new example you will need to know the Gm7 chord.
Now you will play C for 3 measures and on the 4th measure the first 2 beats will be Gm7, the last 2 beats will be C7 and the 5th measure will be the new key F Major.
You might recognize this transition as a 2-5-1 into the key of F Major. This can be used to richen any progression or to change keys in a song at any given time. You can also back cycle much further than the 2nd chord of a progression. You can continue this in a lot of ways. You can back cycle the harmony to sound stronger into the Gm7 by adding like a D7 before it and so on and so on. It is endless really.
Use this info as much as possible! It will help you understand harmony on a whole other level.
Thanks for reading!