The impact of individualised post-exercise blood flow restriction on exercise performance and perceived recovery following strenuous resistance exercise in trained adults.

This study will explore the effects of individualised post exercise blood flow restriction on physical performance and perceived recovery following heavy resistance exercise. A two-armed parallel group randomised trial was used to compare the effects of two interventions on exercise recovery: a post-exercise blood flow restriction group (PE-BFR) and a passive recovery group (CON). Participants were randomised into one of the two groups with a 1:1 ratio. Reporting will be conducted in accordance with the CONSORT statement. The study was approved by the University of South Australia Human Research Ethics Committee (protocol number 203196). All participants will undergo a testing battery to obtain of isokinetic peak knee extension torque, time to peak torque, and countermovement jump (CMJ) height. To obtain peak isokinetic torque and time to peak force, participants will perform three trials of isokinetic unilateral knee extensions per leg, at a speed of 60 degrees per second, with 60s breaks between trials. All trials will be using a HUMAC norm isokinetic dynamometer. During testing, hip angle will be set at 95° (85° backrest angle), with the dynamometer axis of rotation aligned with the most prominent point of the lateral femoral condyle. Participants will be asked to cross their arms on their chest and told to extend their knee as hard and fast as possible with an instructor's verbal encouragement. Isokinetic peak torque will be defined as the highest torque (nm) produced either leg across the six total trials. Time to peak torque will be defined as the time taken to reach maximal torque from the onset of muscular contraction (measured in ms). CMJ height will be obtained using the jump and reach method (Vertec, Sports Imports, Hilliard, OH). Following the testing protocol proposed, all participants will undergo an isokinetic fatigue protocol, consisting of 5 sets of 10 maximal intensity concentric and eccentric knee extension and flexion repetitions set to a speed of 45 degrees per second on the Humac NORM dynamometer. Participants will be verbally encouraged to complete their repetitions ‘as hard and as fast as possible.’ All participants will get 90 seconds rest between sets. After performing post exercise outcome measures, participants will undertake 1 of 2 recovery strategies, in accordance with their random group allocation (PE-BFR or CON). PE-BFR will lay supine in a comfortable position with occlusion cuffs (smart tools USA) fitted to the proximal thigh and inflated to a pressure corresponding with 80% of their individual limb occlusion pressure. The cuffs will remain inflated for 5 minutes, before being deflated for 5 minutes to allow for reperfusion. This will be performed three times each leg, for a total of 15 minutes occlusion per leg. Participants in PE-BFR will remain supine for a total of 30 minutes. CON will lay supine for 30 minutes with occlusion cuffs will placed on the proximal thigh, but the cuffs will not be inflated. All participants will undergo a total of 4 sessions. The baseline testing session (baseline measures, fatigue protocol, and recovery protocol), and three follow up performance testing sessions. All sessions will be conducted by an exercise scientist. It is expected that the initial testing session will take 90 minutes. The following testing sessions will take approximately 30 minutes, as they do not include the recovery or fatigue protocols. Session attendance will be recorded by the exercise scientist to monitor testing adherence.