Acute Effects of Autoregulated and Non-autoregulated Blood Flow Restrictive Bicep Curls on Indices of Arterial Stiffness and Muscle Morphology

Visit 1: Familiarization session. Resting BP; urine sample (female participants only); carotid artery ultrasonography, applanation tonometry anthropometric measurements; body composition measurement; arm curl 1 RM (Appendix 1), familiarization of arm curl exercise with BFR device which includes performing four sets with repetitions (rep) of 30, 15, 15, and 15 at 20% of 1RM with 1 minute of rest between sets.

Visit 2 - 4: Treatment session. Carotid artery ultrasonography, applanation tonometry, and vastus lateralis ultrasonography before and immediately after arm curl exercise. Arm curl exercise with randomized no-BFR or BFR device (auto- or nonautoregulated) will be set at 60% of LOP in supine position) and will include four sets to failure at 20% of 1RM with 2 seconds concentric and 2 seconds eccentric movements per repetition and 1 minute of rest between sets. Cadence will be maintained with an electronic metronome.

The familiarization and treatment sessions will be separated by 1-week.

Devices and Measurements Pregnancy Test. This procedure requires collection of 2-3 teaspoons of urine from all female subjects in a testing cup. Indicator strips (Sekisui Diagnostics OSOM hCG Urine Test Kit, 100% specificity and sensitivity) will be used to test for pregnancy. The P.I. will instruct the participant on the procedure for urine collection. The collection will be completed in a bathroom in Devilbiss Hall. The participant will be instructed to wipe the outer urethra with Castile Soap Towelettes before urinating into a disposable urine collection cup. She will fill the cup with urine, replace the lid and place the cup on a shelf in the bathroom. If the subject is pregnant or the test indicates a current pregnancy, the participant will be immediately notified and will not be able to participate in this study. The participant will be recommended to visit Salisbury University's Student Health Center located in Holloway Hall, room 180 (for SU students) or Wicomico County's Health Department located on 108 E. Main Street in downtown Salisbury, MD for additional support and guidance. The medical waste will be disposed of properly in the Biohazard container inside Devilbiss Hall 316. Spills will be collected with absorptive, disposable towels and surface will be wiped clean with Clorox Wipes. The PI will conduct all the pregnancy tests and the results will be kept confidential.

Autoregulated (AR) and non-autoregulated (NAR) BFR training devices. AR and NAR BFR training devices (Delfi, Vancouver, Canada) will be used for all exercise and testing sessions (Appendix 2). Cuffs will be placed around the right and left proximal arm. The LOP will be set at 60% immediately before exercise and will be applied during the entire exercise set (approximately 30-60 seconds in duration). The AR BFR training device will maintain 60% of the LOP during the entire range of motion. Its diameter will increase during the concentric phase to accommodate the muscle enlargement and decrease during the eccentric phase to accommodate muscle reduction. The NAR BFR training device will also have the LOP set at 60% but the tension will not be constant during the entire range of motion. This is because the diameter of the cuff will not change during the concentric and eccentric phases, causing greater pressures to occur in the thigh during the concentric phase. The LOP will be decreased to 0% immediately after the set is completed.