Do Intramuscular Temperature and Fascicle Angle Affect Ultrasound Echo Intensity Values?

PURPOSE: Ultrasound-derived echo intensity (EI) has been used as a physiological marker for changes in skeletal muscle "quality" with physical training, disuse, aging, and neuromuscular disorders. However, the methodological and physiological factors influencing EI and its longitudinal change are still unclear. Here, we performed two separate experiments to investigate the effects of muscle temperature and fascicle angle, which are known to influence muscle tissue and sound wave properties and therefore affect EI. METHODS: In experiment 1 ( n = 16, 28.0 ± 6.6 yr), vastus lateralis (VL) ultrasonographic images were acquired and intramuscular temperature continuously recorded for 15 min after 20 min of heating to 40.4°C ± 0.7°C using a microwave device. In experiment 2 ( n = 17, 30.2 ± 9.8 yr), VL sonographic images were obtained with the knee both fully extended (0°) and flexed to 90° and EI and fascicle angle measured post hoc . Fascicle movement was tracked during the passive knee flexion to ensure that sonographic images were obtained at the same muscle region. Knee flexion reduced muscle thickness, and we therefore reran analyses calculating EI using identical dimensions to minimize this effect. RESULTS: EI decreased only immediately after the passive heating, and although a moderate, negative correlation was observed between EI and temperature ( rrm = -0.36), the effect of muscle temperature was small ( ß = 0.97 (-1.89 to -0.06) per degree Celsius, P = 0.051). Nonetheless, EI increased as fascicle angle decreased, and a large, negative correlation ( rrm = -0.85) was observed; the effect of fascicle angle on EI was large ( ß = 3.0 (-3.8 to -2.2) per degree, P < 0.01), and this was maintained when analyses were performed at a constant depth of the region of interest ( ß = 3.5 (-4.4 to -2.7) per degree, P < 0.01). CONCLUSIONS: These findings support the hypothesis that fascicle angle meaningfully affects VL EI but provides weak evidence of a temperature effect in vivo . Thus, acute fascicle angle alterations should be accounted for in studies using EI measurements, and longer-term studies should consider whether changes in EI might be partly explained by a change in fascicle angle.

Can supplemental protein to low-protein containing meals superimpose on resistance-training muscle adaptations in older adults? A randomized clinical trial.

PURPOSE: To evaluate the effects of supplementing protein to the low-protein containing meals on selected parameters of muscle mass, strength, and functional capacity in older individuals undergoing resistance training. METHODS: Thirty-one male and female older individuals (60 to 80 years) were randomized into either a whey protein/WP (n = 15, 20 g at breakfast + 20 g at dinner) or placebo-maltodextrin/PL (n = 16, 20 g at breakfast + 20 g at dinner) group. Both groups underwent a supervised, progressive resistance training (2×/week) program for 12 weeks. Maximal isometric voluntary contraction (MIVC) of knee extensors, muscle thickness (MT) of knee extensors and elbow flexors, rectus femoris muscle quality (MQ), body composition (as measured by DXA) and functional capacity [as measured by 30-s sit-to-stand (30ss) and timed-up-and-go tests (TUG)] were evaluated at baseline and after the 12-week intervention. RESULTS: Knee extensor MIVC (WP ∆ = 11.9 ± 11.4% and PL ∆ = 12.9 ± 9.9%) was significantly increased over time, with no between-group differences (all p < 0.05 for main effect of time). Upper- and lower-limb MT were significantly increased over time, with no effect of supplementation (WP: ∆ = 7.0 ± 7.3%, PL: ∆ = 9.5 ± 10.3%; and WP: ∆ = 4.5 ± 5.8%, PL: ∆ = 14.7 ± 28.9%, respectively; all p = 0.001 for main effect of time, respectively). Total and upper-limb lean mass were significantly increased, irrespective of the dietary intervention (WP: ∆ = 0.2 ± 6.3%, PL: ∆ = 1.8 ± 2.9%; and WP: ∆ = 0.10 ± 0.03%, PL: ∆ = 0.15 ± 0.02%, respectively; all p < 0.05 for main effect of time). Main effects of time (all p < 0.05) were also found for 30SS and TUG (fast and usual speeds) (WP: ∆ = 18.2 ± 34.4%, PL: ∆ = 10.4 ± 16.9%; WP: ∆ = 5.4 ± 6.7%, PL: ∆ = 0.7 ± 6.0% and WP: ∆ = 3.3 ± 6.1%, PL: ∆ = 2.3 ± 5.2%, respectively). CONCLUSION: Supplementing additional whey protein to the lowest-protein containing meals (i.e., ~20 g at breakfast and ~20 g at dinner, daily) did not further augment resistance training-induced neuromuscular adaptations (i.e. muscle strength and mass) in healthy older individuals.

Effects of resistance training concentric velocity on older adults' functional capacity: A systematic review and meta-analysis of randomised trials.

Reduced levels of functional capacity in older adults are related to lower quality of life, frailty, and sarcopenia, and can increase risk of falling, fractures and hospitalisation. Resistance training is an effective method to attenuate age-related functional declines. Based on the findings that muscle power and explosive strength are strongly associated with functional performance in older adults, it has been suggested that fast-intended-velocity resistance training may elicit greater improvements in functional capacity when compared to moderate-velocity resistance training. However, currently, there is no high-quality systematic review and meta-analysis supporting this assertion. The present study compared the magnitude of functional capacity improvements following resistance training performed with fast-intentional velocity versus moderate velocity. Pubmed, Scopus, and Web of Science databases were searched from inception to January 2019. The following eligibility criteria for selecting studies was adopted: Participants aged ≥60 years; resistance training based intervention for lower limbs performed solely with slow to moderate concentric velocity (≥2 s for each concentric phase) or solely with the intention of maximising velocity (i.e., as fast as possible); and at least one functional test for lower limbs, with pre- and post-intervention measurements. When studies employed multiple functional tests, a single (pooled) standardised mean difference was calculated and presented as combined functional capacity. In addition, functional tests were grouped accordingly to their specificity for the sub-groups meta-analyses. Fifteen studies were selected (high quality, n = 3; and pre-registered, n = 2). The results presented heterogeneity and small-studies publication bias, leading to a biased advantage for fast-intended-velocity resistance training (95%CI = 0.18, 0.65; I2 = 45%). Short physical performance battery indicated an advantage for fast-intended-velocity resistance training (95%CI = 0.10, 0.94; I2 = 0%). There was no difference for timed up and go (95%CI = -0.07, 0.94; I2 = 48%), 30-s chair stand (95%CI = -0.24, 1.39; I2 = 71%), 5-times chair stand (95%CI = -1.63, 1.27; I2 = 57%) stair climb (95%CI = -1.89, 2.81; I2 = 0%), short walk (95%CI = -0.99, 0.96; I2 = 21%) and long walk (95%CI = -0.59, 1.00; I2 = 0%). These results suggest that there is inconclusive evidence to support the superiority of fast-intended-velocity resistance training to improve functional capacity when compared to moderate-velocity resistance training. These results may have been influenced by the lack of high-quality and pre-registered studies, high heterogeneity, and small-studies publication bias. PROSPERO REGISTRATION NUMBER: CRD42019122251.

Effect of exercise intensity on postprandial lipemia, markers of oxidative stress, and endothelial function after a high-fat meal.

The aim of this study was to compare the effects of 2 different exercise intensities on postprandial lipemia, oxidative stress markers, and endothelial function after a high-fat meal (HFM). Eleven young men completed 2-day trials in 3 conditions: rest, moderate-intensity exercise (MI-Exercise) and heavy-intensity exercise (HI-Exercise). Subjects performed an exercise bout or no exercise (Rest) on the evening of day 1. On the morning of day 2, an HFM was provided. Blood was sampled at fasting (0 h) and every hour from 1 to 5 h during the postprandial period for triacylglycerol (TAG), thiobarbituric acid reactive substance (TBARS), and nitrite/nitrate (NOx) concentrations. Flow-mediated dilatation (FMD) was also analyzed. TAG concentrations were reduced in exercise conditions compared with Rest during the postprandial period (P < 0.004). TAG incremental area under the curve (iAUC) was smaller after HI-Exercise compared with Rest (P = 0.012). TBARS concentrations were reduced in MI-Exercise compared with Rest (P < 0.041). FMD was higher in exercise conditions than Rest at 0 h (P < 0.02) and NOx concentrations were enhanced in MI-Exercise compared with Rest at 0 h (P < 0.01). These results suggest that acute exercise can reduce lipemia after an HFM. However, HI-Exercise showed to be more effective in reducing iAUC TAG, which might suggest higher protection against postprandial TAG enhancement. Conversely, MI-Exercise can be beneficial to attenuate the susceptibility of oxidative damage induced by an HFM and to increase endothelial function in the fasted state compared with Rest.