Stretchy arm issue

I don't think the stretchy arm will work unless your arm was completely straight down X at the time of the cluster application. For this weeks assignment...backflip and run or walk cycle, just turn stretch off and paint weights for the cluster.

Also, parent constrain your cluster to the elbow null. Maintain offset. Break the connection hat drives the X rotate. Then set up the rotation with the expression.

Or if you want to go the higher road, you can follow the advanced arm deformation in my book. Email me with any problems.