Sarcopenia, an age-related decline in skeletal muscle mass and function, dramatically affects the quality of life. Although there is a consensus that sarcopenia is a multifactorial syndrome, the etiology and underlying mechanisms are not yet delineated. Moreover, research about nutritional interventions to prevent the development of sarcopenia is mainly focused on the amount and quality of protein intake. The impact of several nutrition strategies that consider timing of food intake, anti-inflammatory nutrients, metabolic control, and the role of mitochondrial function on the progression of sarcopenia is not fully understood. This narrative review summarizes the metabolic background of this phenomenon and proposes an integral nutritional approach (including dietary supplements such as creatine monohydrate) to target potential molecular pathways that may affect reduce or ameliorate the adverse effects of sarcopenia. Lastly, miRNAs, in particular those produced by skeletal muscle (MyomiR), might represent a valid tool to evaluate sarcopenia progression as a potential rapid and early biomarker for diagnosis and characterization.

IntroductionMicrocurrent has been used to promote tissue healing after injury or to hasten muscle remodeling post exercise post exercise.PurposeTo compare the effects of resistance training in combination with either, microcurrent or sham treatment, on-body composition and muscular architecture. Additionally, changes in performance and perceived delayed onset muscle soreness (DOMS) were determined.MethodsEighteen males (25.7 ± 7.6 years) completed an 8-week resistance training program involving 3 workouts per week (24 total sessions) wearing a microcurrent (MIC, n = 9) or a sham (SH, n = 9) device for 3-h post-workout or in the morning during non-training days. Measurements were conducted at pre and post intervention.ResultsCompared to baseline, both groups increased (p < 0.05) muscle thickness of the elbow flexors (MIC + 2.9 ± 1.4 mm; SH + 3.0 ± 2.4 mm), triceps brachialis (MIC + 4.3 ± 2.8 mm; SH + 2.7 ± 2.6 mm), vastus medialis (MIC + 1.5 ± 1.5 mm; SH + 0.9 ± 0.8 mm) and vastus lateralis (MIC + 6.8 ± 8.0 mm; SH + 3.2 ± 1.8 mm). Although both groups increased (p < 0.01) the pennation angle of vastus lateralis (MIC + 2.90° ± 0.95°; SH + 1.90° ± 1.35°, p < 0.01), the change measured in MIC was higher (p = 0.045) than that observed in SH. Furthermore, only MIC enlarged (p < 0.01) the pennation angle of brachialis (MIC + 1.93 ± 1.51). Both groups improved (p < 0.05) bench press strength and power but only MIC enhanced (p < 0.01) vertical jump height. At post intervention, only MIC decreased (p < 0.05) DOMS at 12-h, 24-h, and 48-h after performing an exercise-induced muscle soreness protocol.ConclusionA 3-h daily use of microcurrent maximized muscular architectural changes and attenuated DOMS with no added significant benefits on body composition and performance.

Purpose This study aimed to compare the post-activation performance enhancement (PAPE) induced by isometric and isotonic exercise on vertical jump performance. Methods 18 healthy trained men (25.8±2.7 years; 78.4±8.2 kg; 175.7±6.1 cm; 25.4±1.8 BMI; 126.72±10.8 kg squat 1-RM) volunteered for this study. They randomly performed two different PAPE protocols: Isotonic squats (ISOTS), which consisted of 2 sets of 3 repetitions at 75% of one-maximum repetition (1-RM); and isometric squats (ISOMS), which consisted of 2 sets of 4 seconds of submaximal (75% of 1-RM) isometric contraction at 90°-knee flexion. Countermovement jump (CMJ) height was tested at baseline and 4 minutes after each conditioning set. Results CMJ height significantly increased after set 1 in both PAPE protocols (ISOMS: p <0.001; ES = 0.34; ISOTS: p <0.001; ES = 0.24), with respect to the baseline jump. However, after set 2 no significant changes in CMJ height were observed for any protocol (ISOMS: p = 0.162; ES = 0.11; ISOTS: p = 0.976; ES = 0.06). No significant differences (p>0.05) were found between both isometric and isotonic exercise conditions. Conclusions Despite both protocols showed similar PAPE effects on CMJ height after set 1, none of the protocols demonstrated greater efficacy in increasing subsequent performance in healthy trained men.

The aim of this study was to compare the concentration of blood lactate [bLa-] and the subjective perception of exertion of trained men in a moderate repetition protocol (MRP) versus a high repetition protocol (HRP) equated for time under tension. Methods A sample of 40 healthy young men (aged, 23.2 ± 4.0 years; height, 177.3 ± 7.0 cm; BMI, 24.3 ± 2.2) performed two sessions of 8 sets of bicep curls with a one-week recovery interval between the trials. In the HRP protocol, 20 repetitions were performed with a cadence of 2 seconds of eccentric and 1 second of concentric, while in the MRP protocol 10 repetitions were performed with 4 seconds of eccentric and 2 seconds of concentric. Cadences were controlled by a metronome. At the beginning and end of each of the sessions, blood lactate was taken at 2, 15, and 30 minutes, and rating of perceived exertion (OMNI-RES) was assessed immediately after completion of each session. Results There were [bLa-] differences between protocols in the MRP 2 min, (5.2 ±1.4); 15 min, (3.2 ±1.2); 30 min, (1.9 ±0.6); p< 0.05, and the HRP 2 min, (6.1 ±1.6); 15 min, (3.7 ±1.1); 30 min, (2.2 ±0.6); p<0.01. OMNI-RES was higher in HRP, (8.8 ±0.7) than in MRP, (7.7 ±0.9). Additionally, a correlation was found between the RPE and [bLa-] values in the HRP protocol (rs = 0.35, p < 0.01).

The objective of this research was to compare the effect of Post-Activation Performance Enhancement (PAPE) exerted on the back squat (BS) versus the barbell hip thrust (HT) on the sprint performance (5- and 10-m). 17 male amateur rugby players participated in the study (age 22.14 ± 2.52 years; body mass 81.06 ± 9.6 kg; height 1.78 ± 0.05 m). All participants performed a dynamic maximum strength test (3RM) in BS and HT at maximum speed. Two randomized sessions were performed inducing PAPE using BS or HT trough three series with three repetitions at 85% 1RM eight minutes before the sprint tests. An ANOVA of repeated measurement, found no differences in the time for 5-m (F = 0.398, P = 0.537, η 2 p = 0.024) or 10-m (F = 2.589, P = 0.127, η 2 p = 0.139). There were no significant differences in the Protocol effect between HT and BS in 5-m or 10-m (F = 2.963, P = 0.104, η 2 p = 0.156 and F = 1.472, P = 0.243 η 2 p = 0.084, respectively). There were also no differences in the Time x Protocol interaction at 5-m (F = 0.001, P = 0.976, η 2 p < 0.001) or 10-m (F = 4.174, P = 0.058, η 2 p = 0.207). The effect size obtained in the results of the sprint tests was small in both exercises (ES < 0.2). None of the BS or HT exercises performed with heavy load induced a significant PAPE phenomenon on the ability to sprint in rugby players.

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Cluster-set resistance training is focused on performance improvements of sports by increasing the repetition maximum, jump height, and efficiency in the sprint. In this commentary, we present relevant aspects to optimize the use of cluster training under the context of muscle hypertrophy. Therefore, we address intra-sets pauses, the number of repetitions per block, and strategies that benefit this methodology. During a cluster set resistance training program, not only the total number of repetitions could be higher, which means a superior total volume, but also a higher mechanical output might lead to potential benefits to muscle hypertrophy.

The Pull-up (PU) is a multi-joint upper body exercise that is included in the physical fitness assessments for tactical occupations such as police, firefighters, and military personnel. This study aimed to evaluate the post-activation performance enhancement (PAPE) in the PU exercise using elastic resistance training (ERT) and traditional resistance training (RT). A total of 18 resistance-trained male firefighters (28.3 [5.6] years; 178.1 [6.8] cm; 78.1 [8.2] kilograms; 24.6 [2.4] kg·m-2) participated in the study and performed four PAPE protocols in a cross-over fashion. Two protocols consisted of three sets of 3 repetitions at 75 and 85% of the maximum repetition (RM) in the lat pull down (LPD-M and LPD-H, respectively). The other two protocols consisted of three sets of 3 repetitions using elastic bands for vertical traction (VTEB) at “moderate” (VTEB- M) and “hard” intensity (VTEB-H), based on the Thera Band perceived exertion scale. Repetitions until failure in the PU exercise were measured before and after the application of the four protocols, with an 8-minute pause before and after the PAPE. Results showed a significant increase on repetitions until exhaustion after all PAPE protocols: LPD-M (P=0.007, d=0.19), LPD-H (P=0.023, d=0.17), VTEB-M (P=0.01, d=0.13) and VTEB-H (P=0.001, d=0.28). The use of ERT and traditional RT at moderate and high intensities represent a proper stimulus for the generation of PAPE in the PU. Keywords: Physical performance, conditioning activity, warm-up exercise, muscle power