I really like this video from Youtube – the authors can be located by clicking on the “youtube” symbol.
Yesterday when running I started to properly understand what Danny Dreyer is writing about regarding the L1/T12 vertebra being the point of separation between the lower and upper body. Ironically I felt it first on the bike with the recent change of coordination and the whole midsection turning towards the extending leg. Yesterday when running downhill I desperately wanted to lengthen my stride but without reaching forwards with the leg. Letting the the whole lower back turn with the pelvis – the leg reaching behind – did the trick. All the same “integrated” sensations recently felt in pedalling technique immediately became apparent. Once again I can see how this will protect the lower back even more. There is no significant twist in the lower back and when the glutes/hamstrings are used on one side (to extend) and the psoas is used on the other side (to flex) everything feels aligned and strong. The stride lengthens significantly compared to when the rotation is confined to lower in the back.