Reliability and validity of the Swaymeter for measuring the trunk control in children with spastic cerebral palsy.

AIMS: To examine the reliability and validity of a simple device, the Swaymeter, for measuring trunk control in children with CP. METHODS: Twenty children with spastic CP participated in this study. Trunk sway was measured while quietly sitting for 30s. Children lean forward or backward as far as possible for measuring dynamic balance range. Test-retest reliability was conducted. The concurrent and construct validity of the Swaymeter was assessed by comparison to the motion capture system and gross motor function measure (GMFM). RESULTS: The reliability of the Swaymeter was moderate to excellent in measuring trunk sway and dynamic balance range (ICCs = 0.696-0.948). Concurrent validity showed good results (r = 0.818-0.997) and construct validity of dynamic balance in anterior direction showed moderate to high correlation with the GMFM (r = 0.599-0.849). CONCLUSION: Assessment of trunk control in a sitting position using the Swaymeter in this study was valid and reliable in children with CP.

Using first bout effect to study the mechanisms underlying eccentric exercise induced force loss.

INTRODUCTION: The first bout of eccentric exercise is known to have a protective effect on the consequent bouts. This effect is still disputable as it is not known whether it protects muscle damage by reducing force production or by improving force recovery in the healing process. The underlying mechanisms of this protective effect have not been fully understood. OBJECTIVES: To determine the mechanisms of this protective effect, three different loads were used for the first eccentric bout. This was done to investigate whether the protective effect is related to the size of the load in the first bout. To determine the neural adaptations, voluntary activation was assessed and to determine the muscular adaptations, the resting twitch was measured. METHOD: Thirty healthy participants were selectively allocated into three groups (low-, moderate- and high-load group) to match for maximal voluntary contraction (MVC) (n = 10 per group). Participants in each group performed only one of the three sets of ten eccentric (ECC) exercises of the elbow flexors (10%, 20% and 40% of MVC) as their first eccentric bout. The second bout of eccentric exercise was performed two weeks later and was identical for all the three groups, i.e., 40% ECC. RESULTS: The results showed that for the first bout, MVC, voluntary activation and the resting twitch displayed significant (p < 0.0001) interaction (group x time). This was not the case however for the second bout as there was no significant (group x time) interaction in all outcome variables immediately after exercise. When the first and second bouts were compared, it was found that the high-load group had faster recovery in MVC at day 1 and 4 corresponding to voluntary activation and only at day 4 corresponding to the resting twitch. CONCLUSIONS: In this study, it was found that high-load exercise aids fast recovery either via neural or muscular adaptations.

The validity and reliability of the Swaymeter for postural sway measurement in typically developing children aged between 7-12 years.

BACKGROUND: The Swaymeter is a simple devicefor measuring postural sway. It consists of a 40-cm-long rod with a vertically mounted pen at the end of the rod that measures the displacement of the body at waist level. RESEARCH QUESTION: This device could be an effective tool for measuring postural sway in children. However, the validity and reliability of the Swaymeter in children has not been evaluated. In this study, we aimed to evaluate the validity and reliability of the Swaymeter in typically developing children aged 7-12 years. METHOD: The Swaymeter procedure was randomly measured in quiet bipedal stance under 4 conditions: eyes open and eyes closed on the floor, eyes open and eyes closed on foam, 30 s were performed in each condition. There were 15 children participated in the validity study. The postural sway was measured concurrently with the motion capture system with two reflective markers on the top of the pen and 12th thoracic vertebra level in three trials with four testing conditions. Additionally, 36 children participated in test-retest reliability. Three measurements were performed on the same day and one week later. RESULTS: Swaymeter had a moderate to good correlation with motion capture system (r = 0.637-0.979). The test-retest reliability of the Swaymeter showed moderate to good reliability for immediate test-retest (ICC = 0.51-0.87). However, inter-session reliability revealed moderate to good reliability except for the AP variable that showed low reliability. Good to excellent reliability was found in sway area variable (ICCs between 0.74 and 0.92) for all measurements. SIGNIFICANCE: Postural sway measure by Swaymeter was valid and reliable in typically developing children aged 7-12 years and suitable for applying to assess postural sway in typically developing children.