Effects of analogy and internal focus instruction on muscular activity, force production and affective response during lifting.

Visit 1: All participants, after a familiarization with questionnaires related to affective responses, and warm up consisting of mobility exercises, hip hinge and Good Morning exercises, 3 dynamics lifts and 3 isometric pulls increasing at 5/10, 7/10 and 9/10 of maximum RPE, participants will perform the following protocol: 3 repetitions of a dynamic task of 25 kg which consists of lifting the load from the ground, similar to a deadlift without receiving any instruction.After a two-minute rest, the isometric deadlift task will begin. Here, participants will perform three maximal repetitions of three seconds duration under the control condition, in which they will be provided with a neutral instruction, such as "try to get up". On visit 2, the same protocol will be performed again from warm-up under "no instruction" or control condition to analyze the reliability and reproducibility of the procedure by measuring the same variables in both tasks. After this, the total number of participants will be randomly divided into two groups. The first group will perform the dynamic task of lifting weights under an explicit instruction. The other group, after familiarization with an instruction by analogy, will perform the task under this condition. Explicit instructions consist in saying: “Don’t pull with your arm” “Make strength with your lower limbs” and analogy: “Make the lift simulating the task before” after putting under invincible resistance on a smith machine and doing a isometric squat movement. Each group, after doing the dynamic task, will perform the isometric task under the same instruction previously performed. All participants, before each isometric repetition and the beginning of dynamic movement, will be instructed again to remember where to place their attention. On visit 3, the same procedure will be performed, counterbalancing the experimental conditions between the groups, making the task dynamic and static under the instruction not used on visit 2, so that the group that was instructed under analogy will perform the tasks under the instruction with explicit features and vice versa. On visit 4, participants will be invited to perform the dynamic and static task again under the instruction that they have adopted as the best for them. People will go 4 times to laboratory in two weeks with at least 48 hours of separation between visits. A sport scientist with 10 years of experience in strength & coach will lead the intervention, supervised by thesis doctoral director. The intervention will be placed face-to-face and will be carried out at the Sport Science Laboratory, located at CED Pirotecnia (Calle Pirotecnia, 41013 Sevilla).