Are the Beneficial Effects of Ischemic Preconditioning on Performance Partly a Placebo Effect?

The acute effect of ischemic preconditioning (IPC) on the maximal performance in the 100-m freestyle event was studied in recreational swimmers. 15 swimmers (21.0 +/- 3.2years) participated in a random crossover model on 3 different days (control [CON], IPC or SHAM), separated by 3-5 days. IPC consisted of 4 cycles of 5-min occlusion (220mmHg)/5-min reperfusion in each arm, and the SHAM protocol was similar to IPC but with only 20mmHg during the occlusion phase. The subjects were informed that both maneuvers (IPC and SHAM) would improve their performance. After IPC, CON or SHAM, the volunteers performed a maximal 100-m time trial. IPC improved performance (p=0.036) compared to CON. SHAM performance was only better than CON (p=0.059) as a tendency but did not differ from IPC performance. The individual response of the subjects to the different maneuvers was very heterogeneous. We conclude that IPC may improve performance in recreational swimmers, but this improvement could mainly be a placebo effect.