“Functional Training”: Implications for strength training; stable vs. unstable
“Functional fitness” has been defined as having the physical capacity to perform activities of daily living in a safe and independent manner without undue fatigue.
Unstable surface training has been found to be suboptimal for increasing strength.
Results showed that training on the unstable surface resulted in a 44% reduction in muscle activity
and a 70% decrease in force output compared to the same activities performed on the stable surface.
After 10 weeks, the stable surface group, of elite athletes, displayed greater performance improvements in all measures studied compared to the unstable surface group, leading the authors to conclude
that use of unstable surfaces may not be optimal for athletic performance improvements in healthy, trained individuals.
Based on available research, it would seem that functional improvements are best achieved when a majority of training is carried out on stable surfaces.
In certain circumstances, it is possible that the addition of unstable surface exercises to a routine may provide a synergistic benefit to functional capacity. McKeon et al. 12 posited that a combination of approximately 75% stable and 25% unstable surface training may be ideal for optimizing static and dynamic balance.