This could mean that the balance aspect of unstable surface training could lead to strength gains irrespective of the loading used. (strengthandconditioningresearch.com)
So unless you're training to be in a circus or are in some form of rehab, please ditch the unstable surface training. (completehumanperformance.com)
Despite the popularity of unstable surface training for developing the trunk musculature, many unstable multi-joint exercises do not produce superior muscle activity compared to their stable equivalents. (strengthandconditioningresearch.com)