The Effects of a Short-Term Endurance Training Program with Blood Flow Restriction Cuffs Versus ACSM Recommended Endurance Training on Arterial Compliance and Muscular Adaptations in Recreationally Active Males

RESULTS: Significant time and group interaction found in cardiac ejection time (p\u3c.05). Significant condition difference between blood flow restriction (BFR) and control for heart rate (HR) max (p=.05) and maximum oxygen consumption (VO2) (p\u3c.05). Significant time difference found in pulse wave velocity femoral to distal (p\u3c.05). Significant repetition main effect (p\u3c.01) for root mean square (RMS) and median frequency (MDF) of Thorstensson. Significant time and group interaction in vastus lateralis of MDF (p\u3c.01). Significant repetition main effect for RMS and MDF ratio (p\u3c.01) Significant time and repetition interaction in vastus lateralis of RMS ratio (p\u3c.03) CONCLUSION: The BFR session showed improvement in both post HR max and post VO2 in comparison to the control group. This may have been caused by increased tolerance to pain/metabolic by-products for HR and increased efficiency at extracting oxygen for VO

Acute Effects of Aerobic Exercise with Blood Flow Restriction on Pulse Wave Velocity in Females

PURPOSE: To investigate the acute effects of a 20-minute walk/run at 40% VO2 with and without blood flow restriction on pulse wave velocity (PWV). METHODS: Seventeen female subjects, between the ages of 18 and 40, signed informed consent and were familiarized with the study protocol, on the same day measurements were assessed: height, weight, body composition, and thigh circumference. Followed by each subject performing the Bruce Protocol on a treadmill. Subjects were asked to come back to the lab hydrated and 8 hours fasted on two different days (separated by at least 48 hours). After reaching hydration, participants were asked to lie down in the supine position for a minimum of 10 minutes and baseline hemodynamics and measurement of PWV using SphygmoCor® CPV Pulse Wave Analyzer. The sites tested were carotid to radial (C-R), carotid to femoral (C-F), and femoral to posterior tibial (F-PT). The randomized testing sessions consisted of two 20-minute walk/run sessions at 40% VO2 intensity with BFR cuffs inflated (BFR), and the BFR cuffs un-inflated (CON). Tightness of the cuffs was set at 55-60 mmHg for BFR, and the cuffs were placed snug enough that they don’t move during exercise for the CON session. The final cuff pressures were achieved by starting at 120 mmHg and increasing progressively by 20 mmHg with 10 s rest in between increments. Upon completion of exercise, post exercise PWV was assessed at immediately, 15, 25, and 45 minutes. RESULTS: No condition*time interaction or condition and time main effects were observed for C-R and C-F sites (p\u3e0.05). There were no significant condition*time interaction or time main effect for the F-PT site (p\u3e0.05), but a significant condition main effect was detected at the 15 minute mark post exercise following the BFR session (p\u3c.01). CONCLUSION: The results suggest that the BFR session resulted in an improved arterial compliance at the F-PT site. This may have been caused by the increased shear stress from blood pooling during the BFR session resulting in a greater release of nitric oxide therefore vasodilation in the lower body. There may be a practical application of using this combination of exercise and settings to help improve cardiovascular health. Since this was an acute study, future training studies should look at the chronic effects on pulse wave velocity using these settings

Effects of Dynamic and Isometric Vibration Exercises on Hemodynamics, Flexibility, and Stress Hormone Levels

PURPOSE: To investigate the acute effects of lower body dynamic (DYN) vs isometric (ISO) exercises on systolic blood pressure (SBP) and diastolic blood pressure (DBP), heart rate (HR), flexibility using the sit and reach, and cortisol (COR) and amylase (AMY) levels measured pre and post exercise with different variations of frequency and amplitude on a power plate in pre-hypertensive females. METHODS: Nine females (age: 23.8 ± 5.1 yrs) performed the ISO and DYN control sessions with the power plate off and ISO and DYN exercises with a combination of low frequency/high amplitude (LF/HA) and high frequency/low amplitude (HF/LA). A 5-min warm-up at 3.0 mph on the treadmill occurred before testing. DYN exercises were performed from standing position to 120° for squat, 90° for lunge, and 90° for squat for a total of four sets for one-min with metronome set at 40 bpm. ISO exercises were performed at the knee angles mentioned previously. Subjects had a 30 sec rest in-between sets. Blood pressure (BP) and HR were recorded using an automated BP cuff pre, post, post 15-min, and post 30-min. Flexibility was recorded after the warm-up and post testing. The passive drool collection method was used to collect saliva to observe the changes in COR and AMY for a total of 1mL for each session before the warm up and post-exercise. Vials were then placed in the freezer to await analysis. RESULTS: There was a significant condition*time interaction (

Differences in Neuromuscular Adaptations After Two Weeks of Conventional vs Blood Flow Restriction Resistance Training

PURPOSE: The purpose of the study was to determine the neuromuscular changes in the rectus femoris (RF) muscle as measured by electromyography (EMG) following short-term resistance training with and without blood flow restriction (BFR). METHODS: 12 males (age = 27.4 ± 6.3 years; height = 171 ± 7 cm; weight = 79.8 ± 13.2 kg) performed six sessions of lower body unilateral resistance training using a leg extension machine. The leg on which BFR was applied was determined through randomization leg dominance Each training session consisted of unilateral knee extensions with and without blood flow restriction. Electromyography data was recorded for each participant during two isometric maximum voluntary contractions (MVC) and two isokinetic knee extension tests (180°/s and 60°/s) using a Biodex System 4 Pro™. EMG was recorded from the RF during these tests. Resistance training consisted of six non-consecutive sessions of knee extension exercises performed in a time frame of two weeks. For the BFR group, subjects trained for a total of four sets (30, 15, 15, 15) at an intensity of 20% 1RM. The contralateral limb was trained with two sets of 11 repetitions at an intensity of 70% 1RM without BFR. The volume of exercises was similar for both conditions. RESULTS: No condition*time interactions or condition and time main effects were observed for root mean square (RMS), mean RMS, yMax, and median frequency (MDF) in both MVC and isokinetic 180°/s and 60°/s (p\u3e0.05). CONCLUSIONS: Both training conditions resulted in insignificant changes and there was no significant difference found between time points. It could be concluded that this was not enough time or stimulus to note major differences across modalities in relation to neuromuscular adaptations of the RF as measured by EMG. Further studies should investigate the effects of higher volume load on neuromuscular adaptations

Barriers to health and social services for street-involved youth in a Canadian setting

Although street-involved youth contend with many health and social problems, the extent to which vulnerable youth engage with supportive services has not been well described. This study sought to examine the prevalence and correlates associated with having difficulty accessing health and social services among a prospective cohort of street-involved youth in Vancouver, Canada. Among 1019 street-involved youth, 650 (64%) reported having difficulty accessing services during the study period. In a multivariate analysis, youth who reported having difficulty accessing services were significantly more likely to be socially and economically vulnerable. Specifically, they were more likely to report severe housing instability, high-intensity drug use, recent interactions with law enforcement, drug dealing, and histories of violence and physical abuse. Study findings point to opportunities to improve access to services among vulnerable youth through removal of blanket age restrictions for youth services, establishing youth-centric social housing, and supporting peer-driven, low-threshold services