2.3.5. Blood Sample Collection and Plasma Protein Analysis
SEPARATION, FRANKLIN
Venous blood samples were collected using a safety winged blood collection needle (0.6 mm × 19 mm × 305 mm) (Henry Schein; Melville, NY, USA) and 10 mL K2 EDTA coated vacutainers (Beckton Dickinson; Franklin Lakes, NJ, USA). Venous blood samples were taken prior to beginning the warm-up for a baseline measure and one hour post back-squat exercise stimulus. Collected blood samples were centrifuged at room temperature for 15 min at 3500 rpm (PowerSpin C856 Centrifuge; UNICO; Dayton, NJ, USA) for plasma separation. All plasma samples were stored at −80 °C until analysis. Venous blood samples were able to be collected on 10 of the 13 participants (1 female, 9 male) in the current study. The remaining 3 participants had incomplete venous blood samples and were excluded from analysis. Enzyme-linked immunosorbent assays were used to assess changes in plasma IL-6 (ab46042; Abcam; Cambridge, MA, USA), VEGF (ab222510; Abcam; Cambridge, MA, USA), and myoglobin (ELH-Myoglobin; RayBiotech; Peachtree Corners, GA, USA) according to manufacturer’s instructions. Following completion of assay procedures, changes in colorimetric absorbance were evaluated using a multi-mode plate reader (Synergy LX; BioTek Instruments; Winooski, VT, USA).In addition to plasma protein analysis, finger-prick blood lactate samples were taken at multiple time points. Lactate measurements were taken prior to beginning the warm-up and twice following the back-squat exercise stimulus: immediately post exercise (before deflating the cuff in BFR condition), and 4 min post-exercise (2 min post cuff deflation in BFR). Capillary blood samples were drawn from the fingertip using contact-activated lancets (BD Microtainer; Beckton Dickinson; Franklin Lakes, NJ, USA) and were examined using a handheld lactate analyzer (Lactate Plus Meter; Nova Biomedical; Waltham, MA, USA).