Abdominal muscle EMG-activity during bridge exercises on stable and unstable surfaces.

OBJECTIVES: To assess abdominal muscles (AM) activity during prone, side, and supine bridge on stable and unstable surfaces (BOSU, Swiss Ball). DESIGN: Prospective comparison study. SETTING: Research laboratory. PARTICIPANTS: Thirty-three healthy volunteers from a university population. MAIN OUTCOME MEASURES: Surface electromyography of the rectus abdominis (RA), the external oblique (EO) and the internal oblique with the transversus abdominis (IO-TA). RESULTS: The AM exhibited the highest activity during prone bridge on a Swiss Ball (RA, EO, IO-TA 44.7 ± 19.2, 54.7 ± 22.9, 36.8 ± 18.6 in % of MVC, respectively). The lowest activity was observed during supine bridge on a stable surface and a BOSU (under 5.0). The lowest ratio analyzed on the basis of the relation of EO and IO-TA activity to RA was obtained during prone bridge on the Swiss Ball (1.4 ± 0.7 for EO, 0.9 ± 0.5 for IO-TA). The highest ratio was obtained during prone bridge on stable surface and supine bridges. CONCLUSIONS: The highest level of activity in the abdominal muscles is achieved during prone bridge on a Swiss Ball. However, this exercise provided the lowest activity of the EO and IO-TA in relation to RA. It is essential to conduct further studies verifying the usefulness of using Swiss Ball during core stability training.

Inter-examiner, intra-session and inter-session reliability of gait measurement.

Three-dimensional gait analysis is commonly used in the objective evaluation of children with idiopathic scoliosis. However, interpretation of results requires carefulness because the gait measurements are error prone. Assessing the reliability of gait analysis in each laboratory may be contribute to assess sources and magnitude of errors in gait analysis as well as determine the direction of the training of examiners.

Intra- and interobserver repeatability of the assessment of anteroposterior curvatures of the spine using Saunders digital inclinometer.

INTRODUCTION: According to the requirements of Evidence Based Medicine, every research tool and method should be subjected to reliability evaluation. A variety of inclinometers are used for the assessment of sagittal plane spinal curvatures in clinical practice. The aim of the study was to evaluate the intra- and interobserver repeatability of measurements of the anterior-posterior spinal curvatures taken with Saunders digital inclinometer. MATERIAL AND METHODS: The study involved 30 healthy subjects (5 males, 25 females) aged 20 to 35 years. The anteroposterior curvatures of the spine were measured in all subjects using a Saunders digital inclinometer. In order to evaluate the intraobserver repeatability of measurements, the results obtained by one investigator were compared. To evaluate interobserver repeatability, the results obtained by three investigators were compared. Additionally, the levels of reliability and measurement error were determined. RESULTS: The measurements conducted by one investigator showed good repeatability for sacral slope, lumbar lordosis, and thoracic kyphosis, including the angle of proximal (Th1-Th6) and distal (Th6-Th12) thoracic kyphosis (p>0.05). For measurements taken by three investigators, interobserver repeatability was achieved for thoracic kyphosis (p>0.05). The reliability of the measurements was good (Cronbach's alpha was 0.9> α ≥0.8), and the measurement error was between 2.8°-3.8°. CONCLUSIONS: The assessment of anteroposterior curvatures of the spine by one investigator provided good repeatability and reliability of measurements. Measurements performed by more than one investigator displayed partial repeatability. The value of the observational error should be taken into account in the interpretation of results of measurements performed with the Saunders inclinometer. The assessment of anteroposterior curvatures of the spine should be preceded by a verification of measurement reliability.