If large clumps of weeds are your problem, then the
Radius Garden Weeder is a good
ergonomic is still your answer. The weeder has another
ergonomic feature, a serrated edge. With the serrated blade you can insert the blade into the soil, pull up on a clump of weeds, and saw through the roots until the weeds come free.
Ergonomic Review of the Radius Garden Weeder
Radius Garden Tools Usability Test