Impacto de um protocolo de corridas intermitentes na assimetria de força de membros inferiores de corredores

Abstract

Running, a highly complex form of locomotion, is widely used to obtain numerous health benefits and optimize athletic performance. Its mechanics are directly influenced by the decrease in muscle strength induced by fatigue and these causes changes in biomechanical variables that are associated with a greater probability of suffering non-contact injuries (LNC). Another factor associated with LNC is strength difference between the lower limbs, that is, force asymmetries. The associations between asymmetry and LNC, Fatigue and LNC are widely discussed in the scientific literature, however studies that associate these factors and the intermittent running protocol are still scarce. Thus, the study aimed to: verify the acute effect of an intermittent running training protocol in dynamic and temporal variables and in the asymmetries of strength of the lower limbs in long-distance runners. Material and methods: The sample consisted of 20 amateur runners (34± 7 years; 63.0 ± 9.61 kg; 56.4 ± 4.99 mL/O2.min-1). Volunteers attended the laboratory for two days. On the first day, there was familiarization of the volunteers with the technique of jumping with countermovement (CMJ) and application of the incremental test to measure the maximum VO2. On the second day, the volunteers performed 3 SCM before and after the intermittent running (IC) protocol which consisted of 12 repetitions each of 400 meters and, after each repetition, 200 meters of active rest. To check whether the individuals were fatigued, the following variables were collected: jump height, heart rate and perceived exertion. The variables of interest were: peak force (relative PF), peak power (PP) and total impulse (I_total), Force production rate (TPF) and asymmetry index (AI). After applying the CI protocol, there was a significant decrease in the values of all variables analyzed compared to the initial condition. As for the Symmetry Index (IS), there were a significant difference in PF, PP and TPF. The IC protocol was able to significantly decrease the values of dynamic variables. Regarding force asymmetries, this protocol had a direct impact on their magnitude, increasing them, with the exception of the asymmetry of the total I_. Thus, signaling that the overloads imposed on each lower limb were different throughout the CI protocol. Regarding force asymmetries, this protocol had a direct impact on their magnitude, increasing them, with the exception of the asymmetry of the total I_. Thus, signaling that the overloads imposed on each lower limb were different throughout the CI protocol. Regarding force asymmetries, this protocol had a direct impact on their magnitude, increasing them, with the exception of the asymmetry of the total I_. Thus, signaling that the overloads imposed on each lower limb were different throughout the CI protocol.