RESUMO
The primary purpose of this study is to examine the effect of two different deadlift barbell height positions on maximal isometric force and subsequent maximal squat jump performance in recreationally-trained men. Fifteen young, healthy, recreationally-trained men (age: 24.7 ± 3.5years, height: 177.1 ± 7.9cm, and total body mass: 81.2 ± 9.8kg) volunteered to participate. All participants performed maximal squat jumps (MSJ) at 90° of knee flexion before (pre-test) and after 4-min (post-test) performing the deadlift exercise using maximal isometric force (MIF) and MIF normalized by body mass (ratioMIF) in two barbell height positions (25% and 75% of the lower limb height, LLH) in a randomized and counterbalanced order. A paired-sample t-test was used to test differences in MIF and ratioMIF between 25% LLH and 75% LLH. Two-way ANOVAs were used for positions (25% LLH and 75% LLH) and time (pre- and post-test) for all dependent variables with an alpha of 5%. Differences were found for MIF and ratioMIF during the deadlift between 25% LLH and 75% LLH (p < 0.001). There was observed an increase in impulse between pre- and post-test only at 75% LLH (p < 0.001), decrease in time to peak force between pre- and post-test only at 75% LLH (p < 0.001), and increase in peak force between pre- and post-test at 75% LLH (p = 0.029). The present results showed that the maximal isometric deadlift exercise at 75% LLH (midthigh) improves subsequent jump performance of the squat jump recreationally-trained men.
RESUMO
The faradaic efficiency of CO2 electroreduction is significantly affected by the thickness of Pd nanoshells on Au cores. The ratio of hydrogen evolution to CO2 reduction was determined by differential electrochemical mass spectrometry. Decreasing the Pd shell thickness from 10 to 1 nm leads to a twofold increase in faradaic efficiency.
