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==Rationale behind Cadence==
Jack Daniels<ref name="jd"/> (the coach not the distiller) found that the slower the cadence, the longer you are in the air and the harder you land. Slow turn over means more impact, which causes more injury.
If you take this to the extreme ('Reductio ad Absurdum'), imagine running with just one step per minute. You would have to leap high in the so that you would be in the air for 30 seconds; the landing force would probably break your legs. Scientific studies have backed this up, showing that an increased cadence reduces the impact forces of running<ref name="Heiderscheit-2011"/><ref name="Mercer-2003"/> with the peak impact force at a cadence of 88 being just over half that that of a cadence of 64<ref name="Hamill-1995"/>. A higher cadence also reduces peak leg deceleration as well as peak impact forces in the ankle and knee joints<ref name="Clarke-1985"/>. Higher cadence is also related to a reduction in overstriding[[Overstriding]]<ref name="Heiderscheit-2011"/>. A cadence of around 90 is also associated with greater running efficiency than lower or higher cadences<ref name="Hamill-1995"/>. Not surprisingly, a higher cadence reduces [[Delayed Onset Muscle Soreness]] and the associated weakness<ref name="RowlandsEston2001"/>. One study<ref name="WILLSON"/> showed that as people become tired, their cadence goes up, and with the higher cadence goes lower impact forces. Although a shorter stride/faster cadence results in less landing force, a longer stride length/lower cadence is associated with less of the impact force reaching the head<ref name="Mercer-2003"/>. The impact forces at a longer stride length are mostly absorbed by the knee<ref name="Derrick-1998"/>.
[[File:Cadence and Impact.jpg|none|thumb|500px|This chart<ref name="Mercer-2003"/> shows the impact forces for three different cadences at the same speed. The thick line shows the Preferred Strike Frequency (PSF) and Preferred Strike Length (PSL), which was a cadence of 84. The thin line has the runners with a 10% slower cadence of 76 and shows increased impact. The dotted line shows 10% faster cadence of 93 and a reduced impact force.]]
[[File:Cadence and VO2.jpg|none|thumb|500px|A chart showing the oxygen cost and heart rate for different cadences. (Cadence values in red added)<ref name="Hamill-1995"/>.]]