Acute Maltodextrin Supplementation During Resistance Exercise.

Most of the research investigating the ergogenic enhancing mechanisms of carbohydrate have been conducted using aerobic based exercise. Therefore, the purpose of this study was to investigate the effects of pre-exercise maltodextrin ingestion on resistance exercise performance, serum insulin, epinephrine, glucose, and muscle glycogen concentrations. In a double blind, cross over, repeated measures design, participants completed four sets to failure at 70% of 1-RM with 45s rest on the angled leg press with or without pre-exercise maltodextrin (2g/kg) after a 3hr fast. Serum glucose, epinephrine, and insulin were assessed at baseline, 30 min post-ingestion, immediately after, and 1hr post-exercise with or without carbohydrate supplementation. Muscle glycogen was assessed from biopsy specimens sampled from the vastus lateralis before supplementation, immediately after exercise, and 1hr post exercise under both conditions. There was no main effect of supplement on resistance exercise performance (p = 0.18). Muscle glycogen concentration decreased across time for both groups (p < 0.001). There was an interaction in serum glucose decreasing more during exercise in the carbohydrate condition (p = 0.026). An interaction occurred showing insulin decreased during exercise in the carbohydrate condition (p = 0.003). Also, there was a main effect of insulin being elevated with carbohydrate consumption (p = 0.027). Epinephrine was decreased across all time points after carbohydrate ingestion (p = 0.023). Carbohydrate supplementation before resistance exercise did not improve leg press performance to fatigue despite increased metabolic substrate availability. These results indicate that pre-exercise dietary carbohydrate will be utilized preferentially during exercise due to decreased epinephrine, decreased serum glucose, and increased insulin concentrations. However, the increases in glycolytic substrate availability will not increase exercise performance or glycogen content following 1hr of recovery.

Effects of Pyrroloquinoline Quinone (PQQ) Supplementation on Aerobic Exercise Performance and Indices of Mitochondrial Biogenesis in Untrained Men.

Objective: Pyrroloquinoline quinone (PQQ) is a novel supplement involved in processes such as mitochondrial biogenesis and cellular energy metabolism. Since endurance exercise and PQQ exhibit similar mechanisms for mitochondrial biogenesis, it is plausible that PQQ may have ergogenic value. Therefore, the purpose of this study was to examine the effects of a six-week endurance exercise training program on mitochondrial biogenesis and aerobic performance in non-endurance-trained males.Methods: Twenty-three males were randomized to consume 20 mg/day of PQQ or placebo (PLC). Both groups followed a supervised six-week endurance exercise training program. Body composition was assessed by dual-energy-x-ray-absorptiometry (DEXA). Aerobic exercise performance and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a biochemical marker for mitochondrial biogenesis, were assessed before and after the six-week endurance training/supplementation program.Results: There were no significant differences between groups in aerobic performance after endurance-training (p > 0.05). However, there were significant improvements in peak oxygen consumption (VO2peak) and total exercise test duration after endurance-training, irrespective of group (p < 0.05). The PQQ group had a significant increase in PGC-1α protein levels from baseline to post endurance training compared to PLC (p < 0.05). Furthermore, the PQQ group had higher PGC-1α protein levels after 6 weeks of endurance training compared to PLC (p < 0.05).Conclusions: Supplementation of PQQ does not appear to elicit any ergogenic effects regarding aerobic performance or body composition but appears to impact mitochondrial biogenesis by way of significant elevations in PGC-1α protein content.

Effectiveness of Fish Oil Supplementation in Attenuating Exercise-Induced Muscle Damage in Women During Midfollicular and Midluteal Menstrual Phases.

McKinley-Barnard, SK, Andre, TL, Gann, JJ, Hwang, PS, and Willoughby, DS. Effectiveness of fish oil supplementation in attenuating exercise-induced muscle damage in females during midfollicular and midluteal menstrual phases. J Strength Cond Res 32(6): 1601-1612, 2018-The purpose of this study was to determine whether the differences in estrogen levels during the female menstrual cycle and fish oil supplementation would attenuate eccentric exercise-induced muscle damage and delayed-onset muscle soreness (DOMS). In a double-blind fashion, 22 physically active females (20.9 ± 1.4 years, 63.5 ± 9.0 kg, 165.2 ± 7.5 cm) were randomly assigned to ingest either 6 g of fish oil (n = 11) or placebo (n = 11) daily for 21 days. Participants underwent an eccentric exercise bout of the knee extensors on 2 occasions during the midfollicular (MF) and midluteal (ML) phases of the 28-day menstrual cycle. Before (PRE), at 6 (6HRPOST), and at 24 hours postexercise (24HRPOST) for each session, participants underwent assessments of DOMS, muscle strength, and had venous blood samples and muscle biopsies obtained. Data were analyzed using a 2 × 2 × 3 repeated-measures multivariate analysis of variance for each criterion variable (p ≤ 0.05). Further analysis of the main effects for the test was performed using separate 1-way analyses of variance. Delayed-onset muscle soreness was significantly greater at the 6HRPOST and 24HRPOST timepoints compared with PRE (p < 0.001). Superoxide dismutase and tumor necrosis factor-alpha (TNF-α) concentrations were significantly higher at the MF phase compared with the ML phase (p < 0.001 and p = 0.05, respectively). There were no statistically significant differences observed for muscle strength, myoglobin, NF-Kß p50, or NF-Kß p65. This study demonstrates that higher levels of estrogen may exert a cytoprotective effect on the sarcolemma.

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.

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.