This one says no, don’t make a difference at all...
“During the incremental exercise test, no significant differences were found in power output, oxygen consumption or heart rate between oval “Q-rings” and conventional chainrings”
“Over the course of the incremental test, blood lactate levels were comparable for the oval “Q-rings” and conventional chainrings”
“During the short sprints performed after the incremental test, there were no statistical differences in power production between oval “Q-rings” and conventional chainrings” -
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3990898/
This one says yes, but only in max sprint power and only at high cadence...
“The Osymetric non-circular chainring significantly maximized crank power by 4.3% during sprint cycling, in comparison with a circular chainring.”
“This maximal power output improvement was due to significant higher force developed when the crank was in the effective power phase.”
“This maximal power output improvement was independent from the shoe-pedal linkage condition.”
“Present benefits provided by the non-circular chainring on pedalling kinetics occurred only at high cadences.” -
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4879434/
I’ve never tried them, no interest. My pedal stroke is fine, no knee pain, feel great on my plain old boring chainrings.