From Ergo Log
Your core muscles will get an even better stimulus if you use suspensions to do the plank. Sports scientists Jeannette Byrne of the Memorial University of Newfoundland discovered this when she did an experiment with 21 students.
To be honest we are not great fans of training gadgets. Give us old-fashioned dumbbells and barbells and we're happy. All those hip things advertised on TV and sold in online stores don't work. That's our rule of thumb.
But we're making an exception for aids like the TRX Suspension System. We've written before about a study that Ronald Snarr did, which showed that suspensions make push-ups more effective, and today when we were in the electronic library we read about Byrne's study, which will soon appear in the Journal of Strength and Conditioning Research.
Byrne attached electrodes to her subjects' abdominal muscles and then got them to do four different versions of the plank, some with and some without suspensions. She then measured which version made the abdominal muscles work hardest.
The figure below shows that doing the plank with your arms in the suspensions, and the version where you have both feet and arms in the suspensions make the rectus abdominis and the external obliques work hardest.
"Performing plank exercises using a suspension training system evoked higher rectus abdominis and external obliques activation, with the arms suspended condition creating the highest activation levels", the researchers write. "Surprisingly, planks performed with upper and lower limbs simultaneously suspended did not appear to have any additional benefits."
J Strength Cond Res. 2014 May 2. [Epub ahead of print].