My first scientific, peer-reviewed publication has been officially accepted into the Journal of Strength & Conditioning Research. The article is titled, “Muscle Activation Patterns While Lifting Stable and Unstable Loads on Stable and Unstable Surfaces”, and is the result of my thesis work. The study compared subjects lifting both barbells and dumbbells on exercise benches and Swiss balls, creating four different conditions.
We found decreased force output when subjects performed the overhead shoulder press exercise when instability was increased. The heaviest loads were lifted during the barbell/bench condition and the lightest loads were lifted during the dumbbell/Swiss ball condition. No significant differences were found in core muscle (rectus abdominis, external obliques, and erector spinae) activation with increased instability.
Further investigations need to be done, but this study showed instability training is not more effective in activating the core than training on stable surfaces (bench) and with stable loads (barbell). Additionally, the study showed that instability training resulted in a decreased force output, which is detrimental to muscle hypertrophy and strength gains. Once the journal article is published, I will be sure to post it.