Effects of Different Ischemic Preconditioning Occlusion Pressures on Muscle Damage Induced by Eccentric Exercise: A Study Protocol for a Randomized Controlled Placebo Clinical Trial

Introduction: due to its mechanical advantage and less metabolic demand, eccentric exercise (EE) has been widely used in rehabilitation and for improving physical fitness. However, EE can induce muscle damage, leading to structural alterations and reduced muscle function, making it necessary to seek alternatives to reduce this damage caused by stress. Thus, ischemic preconditioning (IPC) could represent an aid to reduce the damage caused by EE, because it can mitigate the ischemia-reperfusion injury, and can be used to accelerate the post-exercise recovery process. Objectives: to compare the effects of IPC, using different occlusion pressures, on the acute and delayed responses of perceptual outcomes and on the markers of muscle damage, in addition to verifying whether the technique causes deleterious effects on performance in recovery after eccentric exercise. Methods: a randomized controlled placebo clinical trial will be carried out with 80 healthy men aged 18 to 35 years who will be randomly divided into four groups: IPC using total occlusion pressure (TOP), IPC with 40% more than TOP, placebo (10 mmHg), and control. The IPC protocol will consist of four cycles of ischemia and reperfusion of five minutes each. All groups will perform an EE protocol, and assessments will be carried out before, immediately after, and 24, 48, 72, and 96 hours after the end of the EE to evaluate creatine kinase (CK), blood lactate, perception of recovery using the Likert scale, being sequentially evaluated, pain by the visual analog scale (VAS), pain threshold using a pressure algometer, muscle thickness by ultrasound, muscle tone, stiffness and elasticity by myotonometry, vectors of cell integrity through electrical bioimpedance (BIA), and maximal voluntary isometric contraction (MVIC) using the isokinetic dynamometer. The trial was registered at ClinicalTrials.gov (NCT04420819). Discussion: the present study aims to present an alternative technique to reduce muscle damage caused by EE, which is easy to apply and low cost. If the benefits are proven, IPC could be used in any clinical practice that aims to minimize the damage caused by exercise, presenting an advance in the prescription of EE and directly impacting on the results of post-exercise recovery.Trial registration number: ClinicalTrials.gov, (30765020.3.0000.5402). Registered on 19 May 2020.