Actividad muscular lumbar durante el ejercicio de sentadillas y su relación con sujetos de diferentes características físicas

Abstract

Objective

To identify the relationship between physical variables and the increase of the activity of the lumbar muscles during the performance of squat exercises.

Materials and methods

Twenty-four normal subjects were evaluated. Anthropometric heights, lengths, breadths and girths were measured and an analysis of body proportionality of these variables was made with the Z-phantom model. Measurements were also obtained of back kinematics, muscle flexibility and ankle motion. The squat exercises were performed with and without weight load conditions. Electrical activity of lumbar extensors muscles was measured with superficial electromyography. A statistical analysis was performed by bivariate and multiple linear regression, using the change in the electromyographic activity of the spinal muscles between the no load condition and the loaded weight as the dependent variable.

Results

During squat exercise, no single predictor adequately explained the change of electromyographic activity with load increment. The multiple regression analysis of the change in electromyographic activity of the upper lumbar extensor muscles included femur length, umbilicus girth and z-sitting height (R2=0.57). Z thorax and Z-umbilicus girth in the analysis of the lower back extensors (R2=0.3).

Conclusion

Based on the results of this research, we could not establish a prediction equation of strong electromyographic activity of the paravertebral muscles, although the Z set of variables, femur length and umbilicus perimeter should be considered in future research.