Postural adaptation during arm raising in children with and without unilateral cerebral palsy

Relationship between Fear-Avoidance Beliefs and Reaction Time Changes Prior to and following Exercise-Induced Muscle Fatigue in Chronic Low Back Pain

Background

Reaction time is a reliable indicator of the velocity and efficiency of neuromuscular control and may be associated with fear-avoidance beliefs. However, the effect of exercise-induced muscle fatigue on reaction time in chronic low back pain (cLBP) and its relationship with fear-avoidance beliefs remains poorly understood.

Objectives

This study aimed to reveal the relationship between fear-avoidance beliefs and reaction time changes before and after exercise-induced muscle fatigue in cLBP.

Methods

Twenty-five patients with cLBP were tested by the Biering-Sorensen test (BST) to induce exhaustive muscle fatigue. Total reaction time (TRT), premotor time (PMT), and electromechanical delay (EMD) of dominated deltoid muscle were recorded by surface electromyography during the arm-raising task with visual cues before and after muscle fatigue. The mean difference (MD) of TRT (MDTRT), PMT (MDPMT), and EMD (MDEMD) was calculated from the changes before and after muscle fatigue. Fear-avoidance beliefs questionnaire (FABQ) was applied to evaluate fear-avoidance beliefs before muscle fatigue. In addition, the duration time of BST was recorded for each subject.

Results

TRT and PMT of dominated deltoid muscle were prolonged after exercise-induced muscle fatigue (Z = 3.511, p < 0.001; t = 3.431, p = 0.001), while there was no statistical difference in EMD (Z = 1.029, p = 0.304). Correlation analysis showed that both the MDTRT and MDPMT were positively correlated with FABQ (r = 0.418, p = 0.042; r = 0.422, p = 0.040).

Conclusions

These findings suggested that we should pay attention to both muscle fatigue-induced reaction time delay in cLBP management and the possible psychological mechanism involved in it. Furthermore, this study implied that FABQ-based psychotherapy might serve as a potential approach for cLBP treatment by improving reaction time delay. This trial is registered with ChiCTR2300074348.

Effect of upper extremity constraints on functional and dynamic postural control in children with hemiplegic cerebral palsy

PURPOSE

To compare the effects of upper extremity constraints on functional and dynamic postural control in children with hemiplegic cerebral palsy.

MATERIALS AND METHODS

Twelve children with hemiplegic cerebral palsy and 12 typically developing children ages 5 to 12 years (GMFCS I-II) were evaluated with the Timed Up and Go (TUG) and Biodex Balance System during three upper extremity (UE) conditions: 1) Free UEs (no constraints), 2) Simple UE constraint (unaffected/dominant UE constrained with a sling), and 3) Difficult UE constraint (Simple constraint plus the other UE holding cup of water).

RESULTS

The UE condition had significant effects on Overall Stability Index (OSI) (F_(2,44) = 24.899, p < .001), Medial-Lateral Stability Index (MLSI) (F_(2,44) = 4.380, p = .018), Anterior-Posterior Stability Index (F_(2,44) = 6.187, p = .004), and TUG scores (F_(2,44) = 113.372, p < .001). Group was significant for OSI (F_(1,22) = 7.906, p = .010), MLSI (F_(1,22) = 13.113, p = .002), and TUG (F_(1,22) = 36.282, p < .001).

CONCLUSIONS

The upper extremity appears to have a role in maintaining functional balance and postural stability in children with hemiplegic cerebral palsy and should be considered during intervention programs.

Preliminary Study of the Effect of Training With a Gaming Balance Board on Balance Control in Children With Cerebral Palsy: A Randomized Controlled Trial

OBJECTIVE

A new protocol based on the use of a gaming balance board for children with cerebral palsy was tested.

DESIGN

A total of 56 children with cerebral palsy were enrolled and randomly divided into two groups: experimental and control. The children in experimental group underwent 12 wks of rehabilitation using their foot to play personal computer games with the proposed balance board, whereas those in the control group played personal computer games with a computer mouse in the standing position. Balance control was assessed before and after the intervention using the Zebris FDM System for measuring the center of pressure. The Pediatric Balance Scale and 2-min walk test were used for evaluating functional balance.

RESULTS

In the analysis of covariance, the proposed new balance board used for the personal computer games decreased the postural sway (sway path, F = 6.95, P = 0.011; sway area, F = 11.79, P = 0.001) and improved the performance of the functional balance tests.

CONCLUSIONS

This study demonstrated the possibility that this new gaming balance board can be used for balance control in children with cerebral palsy.

Which biomechanical models are currently used in standing posture analysis?

In 1995, David Winter concluded that postural analysis of upright stance was often restricted to studying the trajectory of the center of pressure (CoP). However, postural control means regulation of the center of mass (CoM) with respect to CoP. As CoM is only accessible by using a biomechanical model of the human body, the present article proposes to determine which models are actually used in postural analysis, twenty years after Winter's observation. To do so, a selection of 252 representative articles dealing with upright posture and published during the four last years has been checked. It appears that the CoP model largely remains the most common one (accounting for nearly two thirds of the selection). Other models, CoP/CoM and segmental models (with one, two or more segments) are much less used. The choice of the model does not appear to be guided by the population studied. Conversely, while some confusion remains between postural control and the associated concepts of stability or strategy, this choice is better justified for real methodological concerns when dealing with such high-level parameters. Finally, the computation of the CoM continues to be a limitation in achieving a more complete postural analysis. This unfortunately implies that the model is chosen for technological reasons in many cases (choice being a euphemism here). Some effort still has to be made so that bioengineering developments allow us to go beyond this limit.