Ischemic Preconditioning Did Not Affect Central and Peripheral Factors of Performance Fatigability After Submaximal Isometric Exercise

Abstract

Behrens et al. Ischemic Preconditioning and Submaximal Exercise determinants, nor muscle activity, SmO 2 , and perceptual responses during submaximal isometric exercise. However, IPC seemed to have an ergogenic effect in a few subjects, which might have resulted from a lower effort perception during exercise. These findings support the assumption that there are 'responders' and 'non-responders' to IPC.

Sex differences in fatigability after ischemic preconditioning of non-exercising limbs

“…Modulation of central mechanisms associated with fatigability such as voluntary activation and presynaptic inhibition [ 14 , 50 ] were not altered by IPC in the current study. This is in accordance with others who showed no effects of a single session of IPC on voluntary activation or H-reflex amplitude of the quadriceps muscles in men, but its effects in women were not evaluated [ 11 , 12 , 51 , 52 ]. Nonetheless, it is suggested that some individuals seem to respond to the IPC technique but others do not [ 10 , 52 , 53 ] and differences in the populations involved, the intensity of contraction and muscles recruited are some factors that may explain the contradictory findings across studies.…”

“…This is in accordance with others who showed no effects of a single session of IPC on voluntary activation or H-reflex amplitude of the quadriceps muscles in men, but its effects in women were not evaluated [ 11 , 12 , 51 , 52 ]. Nonetheless, it is suggested that some individuals seem to respond to the IPC technique but others do not [ 10 , 52 , 53 ] and differences in the populations involved, the intensity of contraction and muscles recruited are some factors that may explain the contradictory findings across studies. For example, physical activity levels were suggested to negatively influence the response to IPC [ 10 ].…”

“…There was no sex difference in physical activity levels in the current study, and therefore this variable likely does not explain the sex difference in response to IPC in our sample. The current study agrees with others that investigated the effects of IPC during fatiguing tasks at submaximal intensities using different muscle groups [ 6 , 52 ], but it is in contrast with others employing a maximal intensity task (e.g., all out sprint) in men [ 11 , 12 , 51 ] and women [ 55 ], and suggests the effects of IPC may be task dependent.…”

Does ischemic preconditioning really improve performance or it is just a placebo effect?

“…In this context, neural pathways are speculated for an end effect through afferent signaling feedback to the brain and then to the target organ (e. g. heart) or by arousing humoral pathways through agents in bloodstream and thus possibly improving O 2 delivery via vasodilatory mechanisms [3,29]. Nevertheless, statements that IPC could mediate physiologic efficiency such as recruitment of additional motor units, enhance muscle deoxygenation and improve skeletal muscle blood flow [1] seems to be refuted based on recent research that have not observed such improvements [5,6]. On the other hand, the training status may play a role in the IPC response [4].…”

“…Despite IPC having been extensively tested due its low cost and easy application, mechanisms for these effects on performance are still lacking. There are arguments and evidences questioning the peripheral/local effect of IPC [5,6] pointing a potential placebo effect [2]. In this sense, recent research have demonstrated no IPC effect on peripheral fatigue and neuromuscular function compared to sham IPC (SHAM) after submaximal isometric [5] or all out isokinetic tests [6].…”