Low back pain suppresses preparatory and triggered upper-limb activation after sudden upper-limb loading.
ABSTRACT A cross-sectional comparative study between healthy controls and patients with chronic low back pain (LBP).
To assess the effect of chronic LBP on biceps brachii muscle activation during sudden upper-limb loading.
Chronic LBP is related to altered trunk muscle function. However, it is not known if these changes are also found in upper-limb function, indicating a general effect.
Surface electromyographic recordings were made from the biceps brachii bilaterally from 22 control subjects without chronic LBP and 29 patients with chronic LBP. Electromyography was recorded during expected and unexpected limb loading, with the activation pattern recorded for analysis at 150 milliseconds before loading, and 3 consecutive 50 milliseconds periods following loading. RESULTS.: Chronic LBP patients had decreased biceps brachii activation before expected perturbation (P = 0.035) and during the third 50-millisecond period (from 100 to 150 milliseconds) after unexpected perturbation (P = 0.010). During the first 2, 50-millisecond periods (from 0 to 100 milliseconds) after the perturbation, the activation was similar.
Chronic LBP did not affect reflex activation of biceps brachii muscles but decreased preparatory and triggered reactions. The finding indicates that back pain may disturb higher level information processing in motor control.
- SourceAvailable from: Heiko Wagner[Show abstract] [Hide abstract]
ABSTRACT: Seeing an action activates neurons in the premotor, motor, and somatosensory cortex. Since a significant fraction of these pyramidal neurons project to the spinal motor circuits, a central question is why we do not automatically perform the actions that we see. Indeed, seeing an action increases both cortical and spinal excitability of consistent motor patterns that correspond to the observed ones. Thus, it is believed that such imitative motor patterns are either suppressed or remain at a sub-threshold level. This would predict, however, that seeing someone make a corrective movement while one is actively involved in the same action should either suppress evoked responses or suppress or modulate the action itself. Here we tested this prediction, and found that seeing someone occasionally stepping over an obstacle while walking on a treadmill did not affect the normal walking pattern at all. However, cutaneously evoked reflexes in the anterior tibial and soleus muscles were modulated as if the subject was stepping over an obstacle. This result thus indicates that spinal activation was not suppressed and was neither at sub-threshold motor resonance. Rather, the spinal modulation from observed stepping reflects an adaptive mechanism for regulating predictive control mechanisms. We conclude that spinal excitability during action observation is not an adverse side-effect of action understanding but reflects adaptive and predictive motor control.PLoS ONE 08/2014; 9(8):e104981. · 3.53 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: It has been reported that altered neuromuscular control of the trunk is associated with lower back pain. In this context reflex delays of the trunk muscles have often been assessed but the reliability of the tests has not been well established. The aim of this study was to test the reliability of measuring reflex delays of the trunk muscles after two types of postural perturbations. 24 Healthy subjects participated in the intra-session study and 13 of them repeated the test protocol within 1-3 weeks, to determine inter-session reliability. Postural reflex delays to unexpected loading and unloading of the arms were assessed in a standing unrestrained position. Each subject performed 40 trials of each test in order to evaluate muscle responses of 5 trunk muscles using surface electromyography. Overall reliability increased with higher number of the averaged trials. Good intra-session (ICC3,1>0.75) and moderate (ICC3,1>0.60) inter-session reliability were reached in most of the monitored trunk muscles. Within the performed number of trials we did not observe any significant systematic intra- or inter-session bias effect. Averaging a higher number of consecutive trials would be recommended in future research and clinical practice.Journal of Biomechanics 06/2014; · 2.50 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Effective and efficient movement is fundamental to sports performance. Movement binds together all of the skills of a game into a coherent flow. Sport -specific training program can induce peculiar neuromechanical adaptations that are commonly considered as signs of aquisition and/or improvement of a specific movement skill. An athlete’s anthropometric and physical characteristics may represent important prerequisites for successful participation in any given sport. Twenty one collegiate volleyball players,(age19.85 +/- 0.83 years; height 181.67 +/- 12.03 cm; weight 72.62 +/- 12.99 kg; training experience 6.76 +/- 2.21 years), were recruited for this study. The purpose of this study was to examine the significance of the impact of body height and weight on the specific motor abilities of volleyball players. The following tests were performed: Block jump, Spike jump, Standing broad jump, Jelka test,T– test, 93639 m test, Obstacle course backwards, Arm plate tapping and Dash 20 m. Regression analysis from package SPSS 15.0 was used for data processing. The results showed that body height and weight had a statistically significant impact on the expression of specific motor abilities of volleyball players.Indeed, it can be assumed that an athlete’s anthropometric characteristics can in some way influence his/her level of performance, at the same time helping to determine a suitable physique for a certain sport.Exercise and Quality of Life, Novi Sad; 01/2013