Peri-exercise co-ingestion of branched-chain amino acids and carbohydrate in men does not preferentially augment resistance exercise-induced increases in PI3K/Akt-mTOR pathway markers indicative of muscle protein synthesis

The effects of a single bout of resistance exercise (RE) in conjunction with peri-exercise branched chain amino acid (BCAA) and carbohydrate (CHO) ingestion on skeletal muscle signaling markers indicative of muscle protein synthesis (MPS) were determined. It was hypothesized that CHO + BCAA would elicit a more profound effect on these signaling markers compared to CHO. Twenty-seven males were randomly assigned to CHO, CHO + BCAA, or placebo (PLC) groups. Four sets of leg presses and leg extensions were performed at 80% 1RM. Supplements were ingested 30 min and immediately prior to and after RE. Venous blood and muscle biopsy samples were obtained immediately prior to supplement ingestion and 0.5 hr, 2 hr, and 6 hr after RE. Serum insulin and glucose and phosphorylated levels of muscle insulin receptor substrate 1 (IRS1), protein kinase B (Akt), mammalian target of rapamycin (mTOR), p70S6 kinase (p70S6K), and 4E binding protein 1 (4E-BP1) were assessed. Data were analyzed by two-way repeated measures ANOVA. Significant group x time interactions were observed for glucose and insulin (p \u3c 0.05) showing that CHO and CHO + BCAA were significantly greater than PLC. Significant time main effects were observed for IRS1 (p = 0.001), Akt (p = 0.031), mTOR (p = 0.003), and p70S6K (p = 0.001). CHO and CHO + BCAA supplementation significantly increased IRS-1 compared to PLC (p = 0.002). However, peri-exercise co-ingestion of CHO and BCAA did not augment RE-induced increases in skeletal muscle signaling markers indicative of MPS when compared to CHO

Creatine supplementation enhances muscle force recovery after eccentrically-induced muscle damage in healthy individuals

Eccentric exercise-induced damage leads to reductions in muscle force, increased soreness, and impaired muscle function. Creatine monohydrate's (Cr) ergogenic potential is well established; however few studies have directly examined the effects of Cr supplementation on recovery after damage. We examined the effects of Cr supplementation on muscle proteins and force recovery after eccentrically-induced muscle damage in healthy individuals. The major finding of this investigation was a significant improvement in the rate of recovery of knee extensor muscle function after Cr supplementation following injury

Whey protein isolate attenuates strength decline after eccentrically-induced muscle damage in healthy individuals

We examined the effects of short-term consumption of whey protein isolate on muscle proteins and force recovery after eccentrically-induced muscle damage in healthy individuals. The major finding of this investigation was that whey protein isolate supplementation attenuated the impairment in isometric and isokinetic muscle forces during recovery from exercise-induced muscle injury

The effect of wave conditions and surfer ability on performance and the physiological response of recreational surfers.

This study investigated the effects of wave conditions on performance and the physiological responses of surfers. After institutional ethical approval 39 recreational surfers participated in 60 surfing sessions where performance and physiological response were measured using global positioning system (GPS) heart rate monitors. Using GPS, the percentage time spent in surfing activity categories was on average 41.6, 47.0, 8.1, and 3.1% for waiting, paddling, riding, and miscellaneous activities, respectively. Ability level of the surfers, wave size, and wave period are significantly associated with the physiological, ride, and performance parameters during surfing. As the ability level of the surfers increases there is a reduction in the relative exercise intensity (e.g., average heart rate as a percentage of laboratory maximum, rpartial = -0.412, p < 0.01) which is in contrast to increases in performance parameters (e.g., maximum ride speed (0.454, p < 0.01). As the wave size increased there were reductions in physiological demand (e.g., total energy expenditure rpartial = -0.351, p ≤ 0.05) but increases in ride speed and distance measures (e.g., the maximum ride speed, 0.454, p < 0.01). As the wave period increased there were increases in intensity (e.g., average heart rate as a percentage of laboratory maximum, rp = 0.490, p < 0.01) and increases in ride speed and distance measures (e.g., the maximum ride speed, rpartial = 0.371, p < 0.01). This original study is the first to show that wave parameters and surfer ability are significantly associated with the physiological response and performance characteristics of surfing

Ingestion of 10 grams of whey protein prior to a single bout of resistance exercise does not augment Akt/mTOR pathway signaling compared to carbohydrate

Background: This study examined the effects of a whey protein supplement in conjunction with an acute bout of lower body resistance exercise, in recreationally-active males, on serum insulin and insulin like growth factor 1 (IGF-1) and Akt/mTOR signaling markers indicative of muscle protein synthesis: insulin receptor substrate 1 (IRS-1), AKT, mammalian target of rapamycin (mTOR), p70S6 kinase (p70S6K) and 4E-binding protein 1 (4E-BP1).Methods: In a randomized, double-blind, cross-over design, 10 males ingested 1 week apart, either 10 g of whey protein (5.25 g EAAs) or carbohydrate (maltodextrose), 30 min prior to a lower-body resistance exercise bout. The resistance exercise bout consisted of 4 sets of 8-10 reps at 80% of the one repetition maximum (RM) on the angled leg press and knee extension exercises. Blood and muscle samples were obtained prior to, and 30 min following supplement ingestion and 15 min and 120 min post-exercise. Serum and muscle data were analyzed using two-way ANOVA.Results: No significant differences were observed for IGF-1 (p > 0.05). A significant main effect for Test was observed for serum insulin (p 0.05). For the Akt/MTOR signaling intermediates, no significant Supplement × Test interactions were observed (p > 0.05). However, significant main effects for Test were observed for phosphorylated concentrations of IRS, mTOR, and p70S6K, as all were elevated at 15 min post-exercise (p < 0.05). Additionally, a significant main effect for Test was noted for 4E-BP1 (p < 0.05), as it was decreased at 15 min post-exercise.Conclusion: Ingestion of 10 g of whey protein prior to an acute bout of lower body resistance exercise had no significant preferential effect compared to carbohydrate on systemic and cellular signaling markers indicative of muscle protein synthesis in untrained individuals

Numerical and Experimental Study on the Addition of Surface Roughness to Micro-Propellers

Micro aerial vehicles are making a large impact in applications such as search-and-rescue, package delivery, and recreation. Unfortunately, these diminutive drones are currently constrained to carrying small payloads, in large part because they use propellers optimized for larger aircraft and inviscid flow regimes. Fully realizing the potential of emerging microflyers requires next-generation propellers that are specifically designed for low-Reynolds number conditions and that include new features advantageous in highly viscous flows. One aspect that has received limited attention in the literature is the addition of roughness to propeller blades as a method of reducing drag and increasing thrust. To investigate this possibility, we used large eddy simulation to conduct a numerical investigation of smooth and rough propellers. Our results indicate that roughness produces a 2% increase in thrust and a 5% decrease in power relative to a baseline smooth propeller operating at the same Reynolds number of Rec = 6500, held constant by rotational speed. We corroborated our numerical findings using thrust-stand-based experiments of 3D-printed propellers identical to those of the numerical simulations. Our study confirms that surface roughness is an additional parameter within the design space for micro-propellers that will lead to unprecedented drone efficiencies and payloads.Comment: 23 Pages, 9 Figure

A Thirty Kiloparsec Chain of "Beads on a String" Star Formation Between Two Merging Early Type Galaxies in the Core of a Strong-Lensing Galaxy Cluster

New Hubble Space Telescope ultraviolet and optical imaging of the strong-lensing galaxy cluster SDSS J1531+3414 (z=0.335) reveals two centrally dominant elliptical galaxies participating in an ongoing major merger. The interaction is at least somewhat rich in cool gas, as the merger is associated with a complex network of nineteen massive superclusters of young stars (or small tidal dwarf galaxies) separated by ~1 kpc in projection from one another, combining to an estimated total star formation rate of ~5 solar masses per year. The resolved young stellar superclusters are threaded by narrow H-alpha, [O II], and blue excess filaments arranged in a network spanning ~27 kpc across the two merging galaxies. This morphology is strongly reminiscent of the well-known "beads on a string" mode of star formation observed on kpc-scales in the arms of spiral galaxies, resonance rings, and in tidal tails between interacting galaxies. Nevertheless, the arrangement of this star formation relative to the nuclei of the two galaxies is difficult to interpret in a dynamical sense, as no known "beads on a string" systems associated with kpc-scale tidal interactions exhibit such lopsided morphology relative to the merger participants. In this Letter we present the images and follow-up spectroscopy, and discuss possible physical interpretations for the unique arrangement of the young stellar clusters. While we suggest that this morphology is likely to be dynamically short-lived, a more quantitative understanding awaits necessary multiwavelength follow-up, including optical integral field spectroscopy, ALMA sub-mm interferometry, and Chandra X-ray imaging.Comment: 7 pages, 4 figures, accepted for publication in ApJ Letters. High resolution images of the cluster can be found at http://hubblesite.org/news/2014/2

Co-ingestion of carbohydrate with branched-chain amino acids or L-leucine does not preferentially increase serum IGF-1 and expression of myogenic-related genes in response to a single bout of resistance exercise

This study determined if the co-ingestion of carbohydrate (CHO) with branched-chain amino acids (BCAA) or L-leucine (LEU) preferentially affected serum IGF-1 and the expression of myogenic-related genes in response to resistance exercise (RE). Forty one, college-age males were randomly assigned to 1 of 4 groups: CHO, CHO-BCAA, CHO-LEU, or placebo (PLC). Resistance exercise consisted of 4 sets of leg press and leg extension at 80% 1RM. Supplements were ingested peri-exercise, and venous blood and muscle biopsies were obtained pre-exercise (PRE), and at 30, 120, and 360 min post-exercise. Serum IGF-1 was determined with ELISA, and skeletal muscle mRNA expression of myostatin, ActRIIB, p21kip, p27kip, CDK2, cyclin B1, cyclin D1, Myo-D, myogenin, MRF-4, and myf5 was determined using real-time PCR. Results were determined with two-way ANOVA for serum IGF-1 and two-way MANOVA for mRNA expression. Serum IGF-1 in CHO and CHO+BCAA was greater than PLC (p \u3c 0.05) but was not affected by RE (p \u3e 0.05). Significant differences were detected between groups for myostatin, ActIIB, MyoD, and myf5 mRNA expression showing CHO to be significantly different than CHO+BCAA, CHO+LEU, and PLC (p \u3c 0.05). At 30, 120 and 360 min post-exercise, p21cip was significantly less than PRE, whereas cyclin D1 was greater than PRE at 120 and 360 min post-exercise (p \u3c 0.05). The co-ingestion of CHO with either BCAA or L-leucine in conjunction with RE had no preferential effect on serum IGF-1 or pre-translational markers indicative of myogenesis