Electromyographic activity of trunk muscles during exercises with flexible and non-flexible poles

Abstract

Abstract.Objective: Hand-held flexible poles which are brought into oscillation to cause alternating forces on trunk, are advocated as training devices that are supposed to solicit increased levels of stabilizing trunk muscle activity. The aim of this study was to verify this claim by comparing electromyographic (EMG) activity of trunk muscles during exercises performed with a flexible pole and a rigid pole. Methods: Twelve healthy females performed three different exercises with flexible and rigid poles. EMG activity of iliocostalis lumborum (IL), multifidus (MU), rectus abdominis (RA), external oblique (EO) and internal oblique (IO), and was continuously measured. The EMG signals were analyzed in time domain by calculation of the Root Mean Square (RMS) amplitudes over 250 ms windows. The mean RMS-values over time were normalized by the maximum RMS obtained for each muscle. Results: The IO showed a 72% greater EMG activity during the exercises performed with the flexible pole than with the rigid pole (p = 0.035). In exercises performed in standing, the IO was significantly more active than when sitting (p = 0.006). Conclusion: As intended, the cyclic forces induced by the oscillating pole did increase trunk muscle activation. However, the effect was limited and significant for the IO muscle only.

Analysis of Heart Rate Variability After Exercise With Oscillatory Pole

“…Despite the intensity of the exercise with the oscillatory pole used in our study have been based on previous studies [3,5] it may be, at least partly, related to the absence of blood pressure responses during the evaluation period.…”

“…We observed that after the exercise there was an increase in parasympathetic tone (SD1 index) 25-30 minutes after exercise compared to rest and a decrease in overall variability (SD2 index) 5-10 minutes and 10-15 minutes after exercise compared to 15 to 20 minutes after exercise. Furthermore, no significant differences were Previous studies reported that exercise with oscillatory pole is considered an isometric anaerobic exercise that provides the contraction of the muscles of the shoulder and trunk [3,5]. In this sense, during the execution of static exercise for lower limbs with 40% of maximum voluntary contraction Mitchell and cols.…”

“…The oscillatory movement of the oscillatory pole (Flexibar ® ) was held by flexion and elbow extension. The oscillatory pole vibrated at a frequency of 5 Hz, and the oscillation frequency of the oscillatory pole was based on an auditory stimulation through a metronome (Quartz Metronome ® ) calibrated at 300 bpm [3]. The exercises with the oscillatory pole ( Fig.…”

“…All exercises were performed for 15 seconds with 50-60 seconds of rest between each exercise. Three repetitions were performed for each exercise [3].…”

“…Heart rate variability was analyzed at the following periods: control rest, 0-5 min, 5-10 min, 10-15 min, 15-20 min, 20-25 min and 25-30 min after the protocol exercise [3].…”