Phosphatidic acid enhances mTOR signaling and resistance exercise induced hypertrophy.

INTRODUCTION: The lipid messenger phosphatidic acid (PA) plays a critical role in the stimulation of mTOR signaling. However, the mechanism by which PA stimulates mTOR is currently unknown. Therefore, the purpose of this study was to compare the effects of various PA precursors and phospholipids on their ability to stimulate mTOR signaling and its ability to augment resistance training-induced changes in body composition and performance. METHODS: In phase one, C2C12 myoblasts cells were stimulated with different phospholipids and phospholipid precursors derived from soy and egg sources. The ratio of phosphorylated p70 (P-p70-389) to total p70 was then used as readout for mTOR signaling. In phase two, resistance trained subjects (n = 28, 21 ± 3 years, 77 ± 4 kg, 176 ± 9 cm) consumed either 750 mg PA daily or placebo and each took part in an 8 week periodized resistance training program. RESULTS: In phase one, soy-phosphatidylserine, soy-Lyso-PA, egg-PA, and soy-PA stimulated mTOR signaling, and the effects of soy-PA (+636%) were significantly greater than egg-PA (+221%). In phase two, PA significantly increased lean body mass (+2.4 kg), cross sectional area (+1.0 cm), and leg press strength (+51.9 kg) over placebo. CONCLUSION: PA significantly activates mTOR and significantly improved responses in skeletal muscle hypertrophy, lean body mass, and maximal strength to resistance exercise.

Effects of oral adenosine-5'-triphosphate supplementation on athletic performance, skeletal muscle hypertrophy and recovery in resistance-trained men.

BACKGROUND: Currently, there is a lack of studies examining the effects of adenosine-5'-triphosphate (ATP) supplementation utilizing a long-term, periodized resistance-training program (RT) in resistance-trained populations. Therefore, we investigated the effects of 12 weeks of 400 mg per day of oral ATP on muscular adaptations in trained individuals. We also sought to determine the effects of ATP on muscle protein breakdown, cortisol, and performance during an overreaching cycle. METHODS: The study was a 3-phase randomized, double-blind, and placebo- and diet-controlled intervention. Phase 1 was a periodized resistance-training program. Phase 2 consisted of a two week overreaching cycle in which volume and frequency were increased followed by a 2-week taper (Phase 3). Muscle mass, strength, and power were examined at weeks 0, 4, 8, and 12 to assess the chronic effects of ATP; assessment performance variables also occurred at the end of weeks 9 and 10, corresponding to the mid and endpoints of the overreaching cycle. RESULTS: There were time (p<0.001), and group x time effects for increased total body strength (+55.3 ± 6.0 kg ATP vs. + 22.4 ± 7.1 kg placebo, p<0.001); increased vertical jump power (+ 796 ± 75 ATP vs. 614 ± 52 watts placebo, p<0.001); and greater ultrasound determined muscle thickness (+4.9 ± 1.0 ATP vs. (2.5 ± 0.6 mm placebo, p<0.02) with ATP supplementation. During the overreaching cycle, there were group x time effects for strength and power, which decreased to a greater extent in the placebo group. Protein breakdown was also lower in the ATP group. CONCLUSIONS: Our results suggest oral ATP supplementation may enhance muscular adaptations following 12-weeks of resistance training, and prevent decrements in performance following overreaching. No statistically or clinically significant changes in blood chemistry or hematology were observed. TRIAL REGISTRATION: ClinicalTrials.gov NCT01508338.

The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance.

Consumption of moderate amounts of animal-derived protein has been shown to differently influence skeletal muscle hypertrophy during resistance training when compared with nitrogenous and isoenergetic amounts of plant-based protein administered in small to moderate doses. Therefore, the purpose of the study was to determine if the post-exercise consumption of rice protein isolate could increase recovery and elicit adequate changes in body composition compared to equally dosed whey protein isolate if given in large, isocaloric doses.

Changes in perceived recovery status scale following high-volume muscle damaging resistance exercise.

Currently no research has investigated the relationship between muscle damage, hormonal status, and perceived recovery scale (PRS). Therefore, the purpose of this study was to determine the effects of a high-volume training session on PRS and to determine the relationship between levels of testosterone, cortisol, and creatine kinase (CK) and PRS. Thirty-five trained subjects (21.3 ± 1.9 years) were recruited. All subjects participated in a high-volume resistance training session consisting of 3 sets of full squats, bench press, deadlifts, pullups, dips, bent over rows, shoulder press, and barbell curls and extensions. Pre-PRS and post-PRS measurements (0-10), soreness, CK, cortisol, and testosterone were measured before and 48 hours after training. Perceived recovery scale declined from 8.6 ± 2.3 to 4.2 ± 1.85 (p < 0.05). Leg, chest, and arm soreness increased from pre- to postexercise. Creatine kinase significantly increased from pre- to postworkout (189.4 ± 100.2 to 512 ± 222.7 U/L). Cortisol, testosterone, and free testosterone did not change. There was an inverse relationship between CK and PRS (r = 0.58, p < 0.05). When muscle damage was low before training, cortisol and free and total testosterone were not correlated to PRS. However, when damage peaked at 48 hours postexercise, free, but not total, testosterone showed a low direct relationship with PRS (r = 0.2, p < 0.05). High-volume resistance exercise lowers PRS scores. These changes are partly explained by a rise in serum indices of muscle damage. Moreover, free testosterone seems to have a positive relationship with PRS.