Effects of Acute Yohimbine Hydrochloride Supplementation on Repeated Supramaximal Sprint Performance.

The purpose of this study was to examine the effects of a single acute dose of yohimbine hydrochloride on repeated anaerobic sprint ability. Physically active females (n = 18) completed two separate repeated supramaximal sprint trials each with a different single-dose treatment: placebo (PL; gluten-free corn starch) or yohimbine hydrochloride (YHM; 2.5 mg). For each trial, participants consumed their respective treatment 20 min before exercise. Following a warm-up, participants completed 3 × 15 s Wingate anaerobic tests (WAnTs) separated by 2 min of active recovery. A capillary blood sample was obtained pre- and immediately post-exercise to measure blood concentrations of lactate (LA), epinephrine (EPI), and norepinephrine (NE). Heart rate (HR) and rate of perceived exertion (RPE) were measured following each WAnT. Findings showed that mean power (p < 0.001; η2 = 0.024), total work (p < 0.001; η2 = 0.061), and HR (p < 0.001; η2 = 0.046), were significantly higher with YHM supplementation versus PL. Fatigue index (p < 0.001; η2 = 0.054) and post-exercise LA (p < 0.001; d = 1.26) were significantly lower with YHM compared to PL. YHM resulted in significantly higher EPI concentrations versus PL (p < 0.001; η2 = 0.225) pre- and post-exercise while NE only increased as a function of time (p < 0.001; η2 = 0.227) and was unaffected by treatment. While RPE increased after each WAnT, no differences between treatments were observed (p = 0.539; η2 < 0.001). Together, these results suggest that acute YHM ingestion imparts ergogenic benefits which may be mediated by lower blood LA and fatigue concomitantly occurring with blood EPI increases. Thus, YHM may improve sprint performance although more mechanistic study is warranted to accentuate underlying processes mediating performance enhancement.

The effects of protease supplementation on skeletal muscle function and DOMS following downhill running.

Protease supplementation has been shown to attenuate soft tissue injury resulting from intense exercise. The aim of this study was to evaluate the effects of protease supplementation on muscle soreness and contractile performance after downhill running. Ten matched pairs of male participants ran at a -10% grade for 30 min at 80% of their predicted maximal heart rate. The participants consumed two protease tablets (325 mg pancreatic enzymes, 75 mg trypsin, 50 mg papain, 50 mg bromelain, 10 mg amylase, 10 mg lipase, 10 mg lysozyme, 2 mg chymotrypisn) or a placebo four times a day beginning 1 day before exercise and lasting a total of 4 days. The participants were evaluated for perceived muscle soreness of the front and back of the dominant leg, pressure pain threshold by dolorimetry of the anterior medial, anterior lateral, posterior medial and posterior lateral quadrants of the thigh, and knee extension/flexion torque and power. The experimental group demonstrated superior recovery of contractile function and diminished effects of delayed-onset muscle soreness after downhill running when compared with the placebo group. Our results indicate that protease supplementation may attenuate muscle soreness after downhill running. Protease supplementation may also facilitate muscle healing and allow for faster restoration of contractile function after intense exercise.