BackgroundSupplementation of combined glutathione (GSH) with L-citrulline in response to a single bout of resistance exercise has been shown to increase plasma nitric oxide metabolites, nitrite and nitrate and cyclic guanosine monophosphate (cGMP), which may play a role in muscle protein synthesis. As a result, in response to resistance training (RT) these responses may establish a role for GSH + L-citrulline to increase muscle mass.This study attempted to determine the effects of an 8-week RT program in conjunction with GSH (Setria®) + L-citrulline, L-citrulline-malate, or placebo supplementation on lean mass and its association with muscle strength. The secondary purpose was to assess the safety of such supplementation protocol by assessing clinical chemistry markers.MethodsIn a randomized, double-blind, placebo-controlled design, 75 resistance-trained males were randomly assigned to ingest GSH + L-citrulline (GSH + CIT), L-citrulline-malate, or cellulose placebo daily while also participating in 8 weeks of RT. The full dose of each supplement was delivered in capsules that were identical in weight, size, shape, and color. Participants completed testing sessions for body composition and muscle strength before and after 4 and 8 weeks of RT and supplementation. Venous blood samples were obtained before and after 8 weeks.ResultsLeg press was increased with RT but was not significantly different between groups (p > 0.05); however, bench press strength was not increased with RT (p > 0.05). There were no significant changes in total body mass, fat mass, or total body water during 8 weeks of RT and supplementation. Lean mass increased in both GSH + CIT when compared to PLC; however, the increase was significant only after 4 weeks. Lean mass and strength were positively correlated (p < 0.05) in GSH + CIT, but not CIT-malate or PLC. Neither RT nor supplementation had any significant effects on blood clinical chemistry variables (p > 0.05).ConclusionCompared to PLC, supplementation of GSH + CIT during resistance training increased lean mass after 4 weeks of RT and was positively associated with muscle strength. However, after 8 weeks of RT there were no significant differences in any of the measured variables.

Hwang, PS, Andre, TL, McKinley-Barnard, SK, Morales Marroquín, FE, Gann, JJ, Song, JJ, and Willoughby, DS. Resistance training-induced elevations in muscular strength in trained men are maintained after 2 weeks of detraining and not differentially affected by whey protein supplementation. J Strength Cond Res 31(4): 869-881, 2017-Resistance training (RT) with nutritional strategies incorporating whey protein intake postexercise can stimulate muscle protein synthesis and elicit hypertrophy. The early phases of training-induced anabolic responses can be attenuated with longer-term training. It is currently unknown if short-term detraining (DT) can restore these blunted anabolic responses during a subsequent retraining (ReT) period. Twenty resistance-trained men (age 20.95 ± 1.23 years; n = 20) were randomized into one of 2 groups (PRO or CHO; 25 g) in a double-blind manner. Participants followed a 4-day per week RT program (4-week RT; 2-week DT; 4-week ReT) while consuming their respective supplement only on workout days during RT and ReT, but every day during DT. At baseline, 4 weeks after RT (post-RT), 2 weeks after DT (post-2-week DT), and after 4 weeks of ReT after DT (post-ReT), leg press strength (LPS) was assessed and rectus femoris cross-sectional area and lean mass changes were assessed by ultrasonography and dual-energy x-ray absorptiometry, respectively. A factorial 2 × 4 (group by time) analyses of variance with repeated measures were used with a probability level at ≤0.05. LPS was elevated throughout the 10-week training study (p = 0.003) with no decrease in LPS after DT in both groups. Although not statistically significant, both groups retained lean mass after DT. A 2-week period of DT appeared to retain muscular strength in resistance-trained men. Therefore, a short-term period of DT can potentially retain lower-body strength in young resistance-trained men irrespective of supplementing with 25 g of whey protein postexercise.

High-intensity interval exercise (HIIE) may impart health benefits beyond what is acquired through moderate-intensity steady state exercise (SSE). Paraoxonase 1 (PON1), an antioxidant associated with highdensity lipoprotein (HDL), may be altered with exercise; however, it is unclear whether HIIE provides a greater stimulus for increasing PON1 antioxidant activity than a comparable or greater amount of SSE. PURPOSE: Determine the influence of HIIE on PON1 concentration and activity relative to a comparable amount of moderate-intensity SSE and a dose that is half that of SSE. METHODS: Seventeen male participants (age 27.8 + 6.4 yr; weight 80.6 + 9.0 kg; BMI 25.1 + 2.4 kg/m 2 ; %fat = 19 + 5; VO2max 52.1 + 7.5 ml/kg/min) underwent HIIE by treadmill running (90% and 40% of VO2reserve in 3:2 min ratio) to expend 500 kcals (H500); HIIE to expend 250 kcals (H250), and; SSE at 70% VO2reserve to expend 500 kcals (M500) in a randomized crossover design. Intensities of all exercise conditions averaged 70% VO2reserve. Blood measures of total antioxidant capacity (TAC) in copper reducing equivalents, HDL ( g/mL), apolipoprotein A-1 (ApoA1: g/L), PON1 concentration (PON1c: g/mL) and arylesterase activity (PON1a: kU/L) were obtained just before, immediately after, 2 hr and 24 hr after exercise. Significant differences were determined using 3 by 4 repeated measures ANOVAs. Effect sizes were calculated to determine the magnitude of dependent variable responses to exercise. RESULTS: Pre-exercise HDL concentration was lower in H250 and increased most in H250 versus other exercise conditions (p < 0.001, ES = 0.83). Other antioxidant responses were similar across exercise conditions. ApoA1 (+ 8.0%) and PON1a (+ 9.3%) increased immediately after exercise and remained elevated 24 hr after exercise (p < 0.0001 for each; ApoA1 ES = 0.85, PON1a ES = 0.57). PON1c was increased 2.4% above baseline at 2 hr post-exercise (p = 0.0296, ES = 0.18) and TAC was elevated 8.6% above baseline at 24 hr post-exercise (p = 0.0227, ES = 0.48). SUMMARY: HDL and HDL antioxidant properties are transiently potentiated by HIIE with as little as 250 kcals of energy expenditure. HDL antioxidant activity and total antioxidant capacity are elevated with HIIE and SSE of moderate intensity in a similar manner and are observed for up to 24 hr after exercise.

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Brachial artery flow-mediated dilation (FMD) is a nitric oxide-dependent measure of conduit artery endothelial function that is potentiated by moderate-and high-intensity steady state exercise (SSE) for up to an hour after exercise; however, it is unclear whether high-intensity interval exercise (HIIE) provides a longer-lasting stimulus for enhancing FMD or greater oxidative and nitrative stress on the vascular endothelium than a comparable or greater amount of SSE. PURPOSE: Determine the influence of HIIE on post-exercise brachial artery FMD and the relationship between FMD and markers of endothelial function relative to a comparable amount of moderate-intensity SSE and a dose that is half that of SSE. METHODS: Seventeen male participants (age 27.8 + 6.4 yr; weight 80.6 + 9.0 kg; BMI 25.1 + 2.4 kg/m2; VO2max 52.1 + 7.5 ml/kg/min) underwent HIIE by treadmill running (90% and 40% of VO2reserve in 3:2 min ratio) to expend 500 kcals; HIIE to expend 250 kcals, and; SSE at 70% VO2reserve to expend 500 kcals in a randomized crossover design. All exercise conditions averaged 70% VO2reserve. Ultrasound measurements of brachial artery FMD and blood measures of total antioxidant capacity (TAC) in copper reducing equivalents, apolipoprotein A-1 (ApoA1: g/L), PON1 concentration (PON1c: g/mL), arylesterase activity (PON1a: kU/L), soluble vascular adhesion molecule-1 (sVCAM-1: ng/mL) and nitrotyrosine (NT: nM) were obtained just before and 2 hr after exercise. FMD responses to exercise were analyzed using 3 (condition) by 2 (sample point) repeated measures ANOVAs. Pearson product-moment correlations of change variables (2 hr post-exercise -pre-exercise values) were calculated to determine relationships between FMD responses and blood variable responses to exercise. RESULTS: Brachial artery FMD responses were unaltered 2 hr after exercise in all three conditions (p > 0.05). FMD responses were correlated with changes in PON1c (r = 0.221, p < 0.0001) and inversely with changes TAC (r = -0.170, p < 0.0001). Changes in s-VCAM1 were correlated with change in NT (r = 0.423, p < 0.0001) and inversely with changes in PON1c (r = -0.177, p < 0.0001). SUMMARY: Brachial artery FMD is unaltered 2 hr after HIIE or SSE of moderate duration in young fit men and does not appear to be related to responses in other markers of endothelial function.