lagging behind
- trailingFollowing behind something
- strugglingExperiencing serious difficulty
- catching upClosing a distance
- slowLacking in speed
- sluggishSlow and inactive
falling behind · delay · straggling · dragging · limping · crawling · pace · distance · gap · last place · rearguard · tail end · procrastinating · dawdling · stalling · slipping · fading · losing ground
position/progress relative to others
lagging behindleading
Guiding or pacing type
ahead · in front · out in front · in the lead · pulling ahead
performance/achievement level
lagging behindexcelling
Performing exceptionally well
outperforming · outpacing · surpassing · ahead of the curve · ahead of schedule