Adding protein to a carbohydrate pre-exercise beverage does not influence running performance and metabolism.

BACKGROUND: To analyze whether pre-exercise CHO+PRO vs. CHO intake distinctly influences running performance and metabolic biomarkers along a various of exercise intensities. METHODS: In a randomized, double blind, counterbalanced, crossover and placebo control design, 10 middle distance runners were tested in 3 occasions. After 10 h of fasting, participants ingested isovolumic beverages (0.75+0.25g·BW-1 of CHO+PRO, 1.0g·BW-1 of CHO and placebo control) 30 min before a treadmill running incremental protocol of 4 min steps until exhaustion. Venous blood was collected at fasting, 30 min after beverage ingestion and after the 3rd and 7th running steps. Oxygen uptake-related variables, including respiratory exchange ratio, heart rate, plasma glucose, insulin, glucagon, free fatty acids, blood lactate concentrations, gastrointestinal discomfort and rate of perceived exertion were measured. RESULTS: The addition of PRO to CHO had no influence on the measured variables, which did not differ between conditions along all incremental protocol intensities. The intake of CHO+PRO (compared to CHO) tended to decrease glycemia (106.5±21.3 vs. 113.6±26.5) and to increase insulinemia (14.4±15.1 vs. 12.7±10.8) at intensities close to maximum oxygen uptake. CONCLUSIONS: The addition of PRO to a pre-exercise CHO beverage had no impact on running performance and related metabolic variables at a wide spectrum of exercise intensities.

Which is the best alternative to estimate muscle mass for sarcopenia diagnosis when DXA is unavailable?

BACKGROUND: Dual x-ray absorptiometry (DXA) is widely adopted to estimate muscle mass for research, but for daily practice is only available in a limited number of facilities. AIM: To elucidate if it is anthropometry or bioelectrical impedance analysis (BIA) the method more concordant with DXA in estimating muscle mass for sarcopenia diagnosis among older adults, and to investigate the impact of several cut-off points in sarcopenia frequency. METHODS: 159 older adults (≥65 years) were included in a cross-sectional analysis. Sarcopenia was identified using the 2018 EWGSOP2 definition, plus previous definitions for muscle mass. Estimation of muscle mass by DXA (appendicular skeletal muscle mass (ASM) and ASM/height2), by BIA (skeletal muscle mass/height2 (SMM/height2) and skeletal muscle mass index (SMI)), and anthropometry (calf and mid-arm muscle circumferences (CC and MAMC, respectively)) was carried out, as well as measurements of handgrip strength and gait speed. RESULTS: Sarcopenia frequency varied from 5.0 to 42.1% depending on the method and cut-off point applied. All surrogate diagnostic criteria had a higher agreement with the DXA defined criterion ASM over ASM/height2. A substantial agreement was also found with BIA SMM/height2 (κ= 0.67), and with BIA SMI (κ= 0.65), and a moderate agreement with MAMC (κ= 0.42), p<0.001. Using the DXA ASM and ASM/height2 criteria as reference, CC showed a specificity of 100% and 94%, respectively. CONCLUSIONS: BIA is a suitable method to evaluate muscle mass in sarcopenia diagnosis when DXA is unavailable. Furthermore, CC showed to be a valid indicator to rule in the presence of sarcopenia.

Neuromuscular changes in football players with previous hamstring injury.

BACKGROUND: Impact of prior injury on myoelectrical activity of the hamstrings during isokinetic eccentric contractions has received increased literature attention. This cross-sectional study aimed to assess neuromuscular adaptations, namely proprioception, core stability, muscle strength, extensibility and activity, in football players with history of hamstring strain injury. METHODS: Seventeen players, 10 with history of hamstring injury and 7 without prior injury underwent isokinetic strength testing, eccentric knee extension at 30 and 120°/s. Myoelectrical activity of bicep femoris and medial hamstrings was calculated at 30, 50 and 100 ms after onset of contraction. Functional tests included core stability, muscle strength, and knee proprioception tests. FINDING: Differences were observed between Hamstring Group injured and uninjured and Control Group dominant limbs in the bicep femoris activity at almost all times in both velocities (p < 0.05). Joint position sense error was higher in the injured side compared to uninjured and control dominant limb; additionally there were also differences between injured and uninjured limb in the triple-hop test. INTERPRETATION: Previously injured side showed deficits in bicep femoris myoelectrical activity after onset of contraction during eccentric testing, proprioceptive deficits, and functional asymmetry.

What is the effect of a Mediterranean compared with a Fast Food meal on the exercise induced adipokine changes? A randomized cross-over clinical trial.

BACKGROUND: Adipose tissue-derived adipokines are pro-inflammatory cytokines involved in metabolic-related diseases and can be influenced by diet and exercise. We aimed to compare the effect of a Mediterranean (MdM) compared with Fast Food (FFM) meal on the exercise induced adipokines changes. METHODS: In a double blinded cross over trial, 46 participants were randomly assigned to one of two standardized iso-energy pre-exercise meals: FFM or MdM-type. Three hours after each meal, participants completed a treadmill exercise test (EC). Serum adiponectin, resistin, PAI-1, lipocalin-2/NGAL and adipsin were determined by Luminex magnetic bead immunoassay. Wilcoxon signed rank test compared changes before/after meal and before/after EC and a linear mixed model evaluated the effect of meals on the adipokine response to exercise, adjusted for confounders. RESULTS: Thirty-nine participants (mean age of 25, with a standard deviation of 5 years) completed the trial (56% females). For both interventions, a significant reduction of adipsin after each meal and a significant increase of lipocalin, PAI-1, adipsin and resistin, after exercise was observed. When exercise was preceded by a MdM meal a higher increase in adipsin levels was seen. CONCLUSION: Acute exercise induced an increase of circulatory levels of adipsin, resistin, lipocalin and PAI-1, but not adiponectin. A pre-exercise Mediterranean meal potentiated the increase of adipsin after the exercise test, which possibly relates to the immune regulatory role of adipsin. These changes suggest a cross-talk between the immune and metabolic immediate response to exercise and its modulation by the pre-exercise diet composition.

Meal-exercise challenge and physical activity reduction impact on immunity and inflammation (MERIIT trial).

BACKGROUND: The effect of a pre-exercise meal as countermeasure to exercise induced immunodepression is poorly known. Also, sedentary behavior is associated with increased cardiometabolic risk but studies on immune changes are lacking. Therefore, we aimed to assess: 1) the impact of a pre-exercise Mediterranean meal (MdM) compared with a fast-food type meal (FFM) on exercise-induced immunological changes and 2) the impact of an induced acute period of sedentary behavior on neuro-immune-endocrine status. METHODS: /Design: This is a two steps clinical trial including: (a) randomized crossover clinical trial, comparing the effect a high-fat/low-nutrient dense meal, FFM, with an isoenergetic similar high-nutrient dense meal, MdM, in the immune response to an exercise challenge (EC) and (b) a pilot trial assessing the neuro-immune-endocrine change induced by acute decreasing by half the usual physical activity level. RESULTS: A total of 46 participants (26 females), median aged 25 years were included. Of those 39-completed protocol, including overweight, physical active and inactive and participants with asthma. There were no differences in the EC between interventions. Dietary factors and physical activity were closely monitored during interventions and kept similar. During physical inactivity induction, 31% reached the target of 50% reduction in mean step number and 77% reached a 30% reduction. CONCLUSION: The use of a pre-exercise meal to modulate immune response and the understanding of the immunological impact of physical inactivity might help to establish future recommendations on how to practice exercise in a safer way and to recognize the potential impact of inactivity.