This page offers general risk reduction measures associated with team handling operations
Note the communication in this lift with four members therefore the load is in the Amber zone. The floor surface has been well maintained. As the load is placed on the floor the operatives can use their leg muscles in order to raise the load.
Emphasis must be on the fact than this is a more controlled lift with excellent communication between the group.
Manual handling at work: A brief guide
Managing upper limb disorders in the workplace
Manual handling assessment charts 
Making the best use of lifting and handling aids