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The aim of this systematic review was (a) to identify the articles that have differentiated muscle action duration (MAD) in the eccentric (ECC) and concentric (CON) muscle action regimen during resistance training (RT) programs and (b) to analyze how MAD affects strength, power, and muscle hypertrophy adaptations. Twenty-four studies were included from 3 electronic databases. The results showed that the RT protocols with medium ECC MAD and fast CON MAD, specifically cadences 2–4/0/1/0, produced the highest improvement values for the development of maximum dynamic strength, both in trained (18–24%) and untrained subjects (10–14%). For the development of maximum power, a medium total repetition MAD of less than 4 seconds and slow total repetition MAD, less than 8 seconds, seems suitable for untrained and trained subjects, respectively, with the condition that CON MAD is explosive or fast (cadence 4–8/0/max-3/0). Finally, muscle hypertrophy could be improved with a total repetition MAD less than 8 seconds in both trained and untrained subjects. The optimal timing of each muscle action to maximize hypertrophic training results is still not entirely clear. In conclusion, the prescription of the MAD, total and phase specific, should be planned according to the adaptations desired in untrained and trained individuals.

Implementing ketogenic diets (KDs) in endurance athletes is currently an interesting topic. This article aimed to systematically review the effects of KDs on anthropometric, metabolic, and performance parameters in endurance sport athletes, highlighting the recommendations about how they should be used. This systematic review was performed under Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and it was performed using 2 databases (i.e., PubMed and Web of Sciences). From the 1,485 studies initially identified, 14 were fully reviewed, and their outcome measures were extracted and analyzed. Regarding anthropometrics, KDs (i.e., daily caloric intake of carbohydrates [CH] < 5%) can lead to a reduction of body weight and percentage fat mass, with a possible impact on maintenance of fat-free mass. Regarding the metabolic adaptations, KDs lead to glycogen storage and fat mobilization, specifically, when using daily caloric intake of CH less than 8%. However, no positive or negative physical fitness and conditioning effects have been found when using KDs. In conclusion, although KDs could be a suitable strategy to induce anthropometric and metabolic changes, this type of diet could not be suitable to improve amateur endurance athletes’ performance.

This study aimed to evaluate the reliability and the level of agreement of the ADR encoder to measure the mean propulsive velocity (MPV) of the bar in the bench press (BP) exercise on the Smith machine. Eleven males (21.6 ± 1.5 years; body mass 76.05 ± 9.73 kg) performed the protocol with isometric phase prior to concentric muscle action (PP) and the protocol in the absence of isometric phase (N-PP) for BP exercise on Smith machine. ADR encoder reported reliability values with almost perfect correlations in all training zones and protocols (PP: ICC = 0.940–0.999, r= 0.899–0.997, CV = 1.56%–4.05%, SEM = 0.0022–0.0153,and MDC = 0.006–0.031 m/s; N-PP: ICC = 0.963–0.999, r= 0.946–0.998, CV = 0.70%–3.01%, SEM = 0.0012–0.0099, and MDC = 0.003–0.027 m/s). Although the levels of agreement were high in both protocols (PP: SEM = 0.0024–0.0204 m/s, MDC = 0.007–0.057 m/s; N-PP: SEM = 0.0034–0.0288 m/s, MDC = 0.009–0.080 m/s), ADR encoder considerably underestimated the MPV values in both protocols (PP: t= −2.239 to −9.486, p< 0.001–0.01; N-PP: t= −6.901 to −17.871, p< 0.001) with respect to the gold standard (T-Force). In conclusion, ADR encoder offers high reliability for the measurement of MPV in bench press exercise performed on Smith machine regardless of their execution mode, in the entire range of intensities. However, this device is not interchangeable with T-Force since it considerably underestimates the MPV values, especially at low loads (0%–40%). Furthermore, the use of too wide load ranges suggests that the data be interpreted with caution, pending further research to corroborate the findings presented.