Raise your left arm horizontal,
with your elbow bent 90 degrees vertically.
Raise your left arm up and down with your index finger extended upward. This indicates the leader wants to speed up.
Position your left hand over your helment, with your fingers extended upward. This indicates the leader wants the group in a single file formation. Usually, this is done for safety reasons.
Extend your left arm upward at a 45 degree angle, with your index and pinkie fingers extended. This indicates that it is safe to return to staggered formation.