Clinical Research Directory

Effect of Blood Flow Restriction Rraining on Rehabilitation After Anterior Cruciate Ligament Reconstruction

Importance: Following anterior cruciate ligament reconstruction (ACLR), patients often experience quadriceps muscle weakness and atrophy, frequently leading to long-term complications. A promising rehabilitation program based on blood flow restriction training (BFRT) seems to be particularly valuable for patients who may be unable to train with heavy loads due recent surgery. Previous studies have demonstrated that BFRT promotes strength gains and muscle mass increases, with adaptations comparable to traditional high-intensity training, despite using low-load resistance exercises. Objective: to evaluate the effect of blood flow restriction training on quadriceps strength and knee biomechanics in a 4-month rehabilitation program of patients who have had an ACL reconstruction. Design: The study will be a two-arm superiority randomized controlled clinical trial. Setting: The trial will be conducted at a work-related injuries specialised hospital, MAZ Hospital, Zaragoza, Spain. Participants: Participants will be active workers who have suffered an acute ACL tear and they have undergone ACL reconstruction (n=60). Intervention: Patients will recieve a 14-16-week supervised accelerated early rehabilitation protocol; one group will complete it applying blood flow restriction training and the other will not. Main Outcome and Measure: The primary outcomes will be peak quadriceps strength and rate of torque development measured both isometrically and isokinetcally with a Isokinetic Dynamometer CON-TREX MG. Limitations: Potential limitations include patients and physiotherapists are not blinded. Conclusions: The focus of the research will examine the impact of blood flow restriction rehabilitation on patients who have undergone ACLR. Relevance: The study has potential to restore quadriceps strength to a greater extent than standard rehabilitation protocol. Moreover, patients will spend less time in the rehabilitation process to return to work compared to standard care.

Quantification of Progenitor Cell Circulation Following Vascular Resistance Exercise Using Delfi Tourniquet System

The purpose of this observational study is to examine how slowing down blood flow to the legs- a practice called blood flow restriction (BFR)- during exercise by applying compression to the legs affects the way stem cells are released into the blood stream. This will be determined by drawing 6 cubic centimeters (ccs) of blood immediately post-exercise after the Delfi Personalized Tourniquet System (PTS) has been removed. 6 ccs of blood will also be taken prior to exercise and at the 20-, 40-, and 60-minute marks after exercise. The main question of this study is: • Will the levels of stem cells extracted before and after exercise be the same if blood flow is restricted during exercise? In this study, participants will undergo the following: * 6 ccs of blood extracted from the forearm prior to exercise to establish a baseline * 3 exercises- seated leg extension, semi-reclined leg press, and seated hamstring curl- consisting of 4 sets of 30-15-15-15 repetitions per exercise; resistance will be set to 30% of one-rep maximum (1-RM) * Additional 6 cc blood draws will be performed immediately post-exercise and after 20, 40, and 60 minutes have elapsed

Comparing Vascular Responses to Aerobic Exercise With and Without Blood Flow Restriction in Young and Older Adults

Aging is a major risk factor for cardiovascular disease (CVD), contributing to progressive macrovascular and microvascular dysfunction. Macrovascular impairments, such as arterial stiffening and endothelial dysfunction, reduce nitric oxide (NO) bioavailability, leading to hypertension and impaired blood flow regulation. Microvascular dysfunction exacerbates cardiovascular decline by compromising capillary perfusion and tissue oxygenation, increasing susceptibility to ischemic events. Preserving vascular function is essential for maintaining cardiovascular health in aging populations. Low-intensity aerobic exercise (LIAE) improves cardiovascular health and mobility, particularly in populations unable to perform high-intensity exercise. However, LIAE alone often fails to induce significant vascular adaptations, such as improved arterial compliance or endothelial function, highlighting the need for optimized interventions. Blood Flow Restriction (BFR) enhances vascular adaptations during low-intensity exercise by inducing localized hypoxia, stimulating endothelial function and arterial remodeling. While BFR may transiently increase blood pressure and arterial stiffness, its vascular benefits resemble those of high-intensity exercise at lower workloads. However, research on BFR's acute vascular effects during aerobic exercise in older adults remains limited. Current studies have focused on perceptual and hemodynamic responses to LIAE+BFR but lack direct assessments of macrovascular (e.g., flow-mediated slowing) and microvascular function. Older adults may exhibit distinct vascular responses, yet data are scarce. This study examines acute vascular responses to LIAE+BFR and high-intensity interval exercise (HIIE) in young and older adults. Hypothesis: 1. BFR combined with LIAE will elicit greater acute microvascular and macrovascular responses in older adults than in younger adults. 2. These responses will be comparable to HIIE without BFR, suggesting BFR enhances LIAE's efficacy to high-intensity levels. 3. Any transient vascular dysfunction (e.g., increased arterial stiffness) will normalize within 30 minutes post-exercise, supporting safety in aging populations.

Dance and Blood Flow Restriction as Balance Training for Older Women

Falls are one of the leading causes of hospitalization and mortality among older adults (aged 65+) in Canada. Falls result from postural instability following age-related declines in muscle strength which begin in the 5th decade of life. Older women have higher rates of injury from falls due to greater deterioration of bone mass density and lower levels of physical activity when compared to men. Participation in physical activity and exercise has been shown to slow these age-related declines in postural stability by improving muscle function as well as proprioceptive and sensory systems, however the majority of older women are inactive. Dance has been used to inspire physical activity uptake among older women, and is particularly good for balance due to its both sensory and motor aspects that focus on precise execution of movement. Dance interventions have been found to improve postural stability and balance confidence. Post-pandemic, online dance classes have provided greater accessibility to exercise interventions aimed at promoting balance. These help reach women facing transportation barriers, who have a fear of exercising with others, women with time-consuming caregiver roles at home etc. While beneficial, the intensity of online classes must be lower to ensure safety, thereby limiting physiological stimulus for adaptations. As typically higher intensity exercise is needed to promote muscle strength there may not be adequate stimulus for adaptations. Furthermore, there is little evidence of strength gains even from in-person dance classes. Blood flow restriction may offer an easy and cost-effective way to mimic higher intensity exercise and boost training benefits. Blood flow restriction has been found to boost strength during low-intensity resistance training, but there is little information on adaptations after balance training or potential transfer to reduce the risk of falls. This 12-week online exercise intervention investigates whether blood flow restriction during dance classes can augment strength, dynamic balance and postural stability of older women aged 65 years and above. Two groups of older women will participate in twice weekly 75 minute ballet and modern-dance classes over Zoom. One group will be randomized to wear 5 centimeter elasticised blood flow restriction bands on their proximal thighs during the classes. Bands will be tightened to a 7/10 of perceived tightness. Postural stability will be assessed using 9, 30-second trials of quiet standing on a force platform in conditions of eyes-open, eyes-closed and on a foam block - trials will be staggered to reduce fatigue effects. Trials will also be video recorded for kinematic analysis of shoulder and hip displacement using Kinovea. Dynamic balance will be assessed using the Star Excursion Balance Test. Participants will be asked to stand on one foot in the middle of the star and reach their other leg as far as they can above the line. The distance the participant reaches in each direction will be recorded and normalized by limb length. Strength will be assessed using the 30-second Sit-to-Stand test and Calf-Raise Senior test. Both tests involve participants doing the maximum number of repetitions possible within a 30-second time frame. Finally scales of fears of falling and overall perceptions of health will be collected. It is expected that this study will have great practical implications as the accessibility of this program can provide opportunities to older adults from various remote locations to increase their levels of physical activity in a safe manner. The affordability may also aid in adoption by community health and recreation centers as an easy-to-implement program that helps to reduce the risk of falls of older women, thereby promoting independence and quality of life.

Blood Flow Restriction and Functionality in Older Adults

Resistance training is beneficial for stimulating muscle and bone growth and is uniquely important for older adults to avoid frailty and to maintain bone density. Seniors tend to be anxious to use a large resistance or try heavier weights as it is not common for them to exercise this way. Therefore, blood flow restriction is a fantastic way to increase intensity while keeping the resistance low. Wearing blood flow restriction straps allows the muscles to adapt to working at a lower oxygen pressure, therefore, mimicking a higher intensity. Additionally, as we age, oxygen consumption decreases, commonly due to loss of lean body mass and a reduced maximum heart rate. However, resistance training can counteract these declines by reducing the resting heart rate and improving cardiac output, therefore, bettering oxygen consumption. The study will consist of 10 weeks of resistance exercises performed twice per week. The classes will be open to seniors of 60 years of age or older. The classes will be held on zoom- allowing for easy access, no travel and an opportunity for seniors to be active in their own home. The exercises will consist of general resistance training movements focusing all the major muscle groups. One group of seniors will wear blood flow restriction bands on both legs at the upper thigh and a control group which will complete the same exercise classes with no restriction. Before, at midpoint and after the 10 weeks, the participants will perform strength tests using the BIODEX and three functional tests focusing on the lower extremity. There will be a practice trial for all the functional tests where results are not recorded. Once the practice is completed, the participants will have one trial of each test. The BIODEX is a dynamometer that allows testing in many different settings including rehabilitation. During the functional tests, the participants will be asked to wear a VO2 non-invasive mask (VO2 Master) to measure their oxygen consumption. The functional tests will include: * Sit to stand: rise from a chair as many times as possible without using hands or arm rests to help. * Timed up a go: Rise from a chair and walk 8ft as fast as possible without running and return to sit on the chair. * Sitting-rising test: lowering to the floor and coming back up without using hands, knees or arms. Thus, the purpose of this study is three-fold: 1) To assess the effects of the 10-week online exercise intervention on strength and functionality 2) To assess the effects of the 10-week intervention on oxygen consumption using a VO2 non-invasive mask and 3) To assess if the addition of blood flow restriction over a 10-week intervention increases the improvements in strength and oxygen consumption compared to the control group.