Eliott Arroyo

Effects of supine rest duration on ultrasound measures of the vastus lateralis

Due to the potential for intramuscular fluid shifts from changing body position, researchers often utilize a 10‐ to 15‐min period of supine rest as a standardizing procedure prior to ultrasound assessment of the lower limbs. However, no previous research has observed the changes in muscle morphological characteristics via ultrasonography of the lower limbs depending on the length of time of supine rest to determine whether 10–15 min of supine rest is necessary. The aim of this study was to examine changes in muscle morphology of the vastus lateralis (VL) at various time‐points over the course of 15 min of supine rest.

Comparisons in the Recovery Response From Resistance Exercise Between Young and Middle-aged Men

Abstract Gordon, JA III, Hoffman, JR, Arroyo, E, Varanoske, AN, Coker, NA, Gepner, Y, Wells, AJ, Stout, JR, and Fukuda, DH. Comparisons in the recovery response from resistance exercise between young and middle-aged men. J Strength Cond Res 31(12): 3454–3462, 2017—The purpose of this study was to compare the effects of a bout of high-volume isokinetic resistance exercise protocol (HVP) on lower-body strength and markers of inflammation and muscle damage during recovery between young and middle-aged adult men. Nineteen recreationally trained men were classified as either a young adult (YA: 21.8 ± 2.0 years; 90.7 ± 11.6 kg) or a middle-aged adult (MA: 47.0 ± 4.4 years; 96.0 ± 21.5 kg) group. The HVP consisted of 8 sets of 10 repetitions, with 1 minute of rest between each set, performed on an isokinetic dynamometer at 60°·s−1. Maximal voluntary isometric contractions and isokinetic peak torque (PKT) and average torque (AVGT) (measured at 240° and 60°·s−1, respectively) were assessed at baseline (BL), immediately post (IP), 120 minutes, 24, and 48 hours after HVP. Blood was obtained at BL, IP, 30, 60, 120 minute, 24, and 48 hours after HVP to assess muscle damage and inflammation. All performance data were analyzed using repeated measures analysis of covariance, whereas all inflammatory and muscle damage markers were analyzed using a 2-way (time × group) repeated measures analysis of variance. Results revealed no between-group differences for PKT, AVGT, or rate of torque development at 200 ms (RTD200). No between-group differences in myoglobin, creatine kinase, C-reactive protein, or interleukin-6 were observed. Although BL differences in muscle performance were observed between YA and MA, no between-group differences were noted in performance recovery measures from high-volume isokinetic exercise in recreationally trained men. These results also indicate that the inflammatory and muscle damage response from high-volume isokinetic exercise is similar between recreationally trained, young, and middle-aged adult men.

Tumor necrosis factor-alpha and soluble TNF-alpha receptor responses in young vs. middle-aged males following eccentric exercise.

Background Tumor necrosis factor‐alpha (TNF‐&agr;) has been shown to be implicated in both muscle regeneration and muscle wasting. However, it remains unclear whether TNF‐&agr; is responsible for the age‐related losses in muscle size and function. Also, due to the high clearance rate of TNF‐&agr; from circulation, analyzing the circulating levels of soluble TNF‐&agr; receptors 1 and 2 (STNFR1 and STNFR2) may provide a better indication of inflammatory events. The aim of this study was to examine changes in circulating concentrations of TNF‐&agr;, STNFR1, and STNFR2 following acute eccentric exercise in young (YA) and middle‐aged (MA) men. Methods and materials Nine YA (N = 9, 21.8 ± 2.2 y, 179.5 ± 4.9 cm, 91.2 ± 12.2 kg, 21.8 ± 4.3% body fat) and ten MA (N = 10, 47.0 ± 4.4 y, 176.8 ± 7.6 cm; 96.0 ± 21.5 kg, 25.4 ± 5.3% body fat) men completed an acute muscle damaging protocol (MDP). Blood samples were obtained at baseline (BL), immediately (IP), 30‐minute (30P), 60‐minute (60P), 120‐minute (120P), 24‐hour (24H), and 48‐hour (48H) post‐MDP. Lower body performance was assessed via isokinetic dynamometer at BL, IP, 120P, 24H, and 48H. Results YA displayed higher values of peak torque (p = 0.023) and mean torque (p = 0.036) at BL. No significant group differences were observed for markers of muscle damage or TNF‐&agr;. Plasma concentrations of TNF‐&agr; were unchanged following MDP. STNFR1 concentrations were significantly higher in the YA group compared to MA (p = 0.036). Significant time effects were observed for STNFR1 (p < 0.001) and STNFR2 (p = 0.001). With both groups combined, serum STNFR1 was decreased at 30P (p = 0.001), while STNFR2 was decreased at 30P (p = 0.008), 60P (p = 0.003), and 120P (p = 0.002) relative to BL. Conclusions The pro‐inflammatory response to muscle damage does not appear to decline at middle age when individuals are recreationally trained. However, young men showed significantly higher serum STNFR1 concentrations than middle age men. This may suggest that natural inhibitors of TNF‐&agr; decline as early as middle age. HighlightsAge‐related changes in circulating TNF‐&agr; and STNFR2 are not apparent at middle‐age but rather may only be seen in older age.The pro‐inflammatory response to muscle damage does not appear to decline at middle age in recreationally trained men.Young men showed significantly higher baseline serum concentrations of STNFR1 compared to middle aged men.The findings of this study suggest that natural inhibitors of TNF‐&agr; may decline as early as middle age.