He has lost connection with the Head, from whom the whole body, supported and held together by its ligaments and sinews, grows as God causes it to grow.
Without being connected to the head a body may flop around for awhile but it will not last and will accomplish nothing. That is how Paul describes these mystics as they flop around without the direction of God through the Holy Spirit. The ligaments and sinews speaks to action as without them, nothing can be done physically. When we were babies, we all had to learn how to operate these bodies that God gave us and the same applies to our walk with the Lord. By following Christ's leading through the Spirit, we will be able to put our faith into action and, as we grow, He will show us how to use our bodies to their true potential for God's glory. This is true for each of us individually as well as for churches (groups of believers). If a group of believers is being taught and led by one that does not understand how to use the power that God has given (by listening to the Spirit), we can't expect much to happen in their lives or the life of that local group.