Posturography Comparison and Discriminant Analysis Between Individuals With and Without Chronic Low Back Pain.

OBJECTIVE: The aims of this study were to evaluate the center of pressure (CoP) in individuals with chronic low back pain (LBP) compared with matched controls and perform discriminant analysis to detect which CoP variables differentiate the groups. METHODS: Thirty-two participants with LBP and 33 matched controls were evaluated on a force plate in a bipedal static position for 30 seconds in 2 conditions: eyes open (EO) and eyes closed (EC). Two discriminant analyzes were performed to detect which CoP variables could discriminate between groups. RESULTS: Those with LBP had higher values (ie, poorer balance) for most variables compared with the control group. With EO, total displacement of sway (TDS) was as follows: LBP group (median [25%-75%]) 31.77 (26.39-41.79) cm, control group 27.21 (22.29-31.78) cm, P = .008 and area: LBP group 3.31 (2.33-4.68) cm2, control group 1.77 (1.3-2.71) cm2. With EC, TDS was as follows: LBP group 49.6 (39.65-68.15) cm, control group 38.77 (30.36; 45.65) cm, P = .003 and area: LBP group 4.68 (2.6-7.28) cm2, control group 2.4 (2.1-3.34) cm2. The discriminating variables in the EO condition were the TDS for the LBP group and the anteroposterior mean velocity for the control group, while in the EC condition they were mediolateral dispersion and area for the LBP group. CONCLUSION: Individuals with chronic LBP had worse postural control performance than matched controls, and it is possible to characterize those with and without LBP with CoP variables.

Postural Sway, Balance Confidence, and Fear of Falling in Women With Knee Osteoarthritis in Comparison to Matched Controls.

BACKGROUND: Osteoarthritis (OA) is a chronic degenerative disease that commonly affects the knee joints. Individuals older than 65 years of age with knee OA have a greater risk of falls. However, there has been limited examination of the parameters of postural sway (increased time, speed, and postural sway area [center of pressure{CoP}]), and OA of the knee. OBJECTIVES: The primary objective of this study was to determine whether the CoP variables discriminate between patients with knee OA and matched healthy volunteers, and to correlate the CoP variables with the Activities-Specific Balance Confidence Scale (ABC) and Falls Self-Efficacy Scale (FES). The secondary objective was to compare the CoP of older women with OA with a control group in bipedal support condition with eyes opened and closed. DESIGN: Cross-sectional study. SETTING: University Biomechanics Laboratory. PARTICIPANTS: A total of 22 participants were divided into the following 2 groups of 11 participants each: an OA group (mean = 68 years, standard deviation = 7.4 years) and a control group (mean = 66 years, standard deviation = 4.4 years). METHODS: Static postural balance was measured by a portable force platform. Data were collected in both visual conditions (eyes open and closed), in random order. Three attempts of 30 seconds were allowed for each participant on the force platform, with a 1-minute interval between attempts. MAIN OUTCOME MEASURE: Variables were the CoP total displacement of sway (TDS, in centimeters), anteroposterior amplitude displacement (APAD, in centimeters), medial-lateral amplitude displacement (MLAD, in centimeters), total mean velocity (TMV, in centimeters per second), and dispersion of the center of pressure (AREA, in centimeters squared). RESULTS: The postural sway analysis found statistically significant differences in the eyes open condition for the TDS (P = .020), APAD (P = .042), TMV (P = .010), and AREA (P = .045). In the discriminant analysis, none of the CoP variables were able to classify the groups (P = .15). The correlation analysis showed that only the AREA with eyes closed was associated with the ABC Scale (rho = -0.42). CONCLUSIONS: Women with knee OA had greater postural sway when compared with a control group for the eyes open condition. CoP variables could not discriminate between the groups. The AREA was negatively correlated with the ABC Scale, when the eyes were closed. LEVEL OF EVIDENCE: III.

Reliability of ground reaction forces in the aquatic environment.

The aim of this study was to verify the reliability of the kinetic parameters of gait using an underwater force platform. A total of 49 healthy participants with a median age of 21years were included. The kinetic gait data were collected using a 0.6×0.6×0.1m aquatic force plate (Bertec®), set in a pool (15×13×1.30m) with a water depth of 1.20m and water temperature of 32.5°C. Participants walked 10m before reaching the platform, which was fixed to the ground. Participants were instructed to step onto the platform with their preferred limb and data from three valid attempts were used to calculate the average values. A 48-h interval between tests was used for the test-retest reliability. Data were analyzed using interclass correlation coefficients (ICC) and results demonstrated that reliability ranged from poor to excellent, with ICC scores of between 0.24 and 0.87 and mean differences between (d¯)=-0.01 and 0.002. The highest reliability values were found for the vertical (Fz) and the lowest for the mediolateral components (Fy). In conclusion, the force platform is reliable for assessing the vertical and anteroposterior components of power production rates in water, however, caution should be applied when using this instrument to evaluate the mediolateral component in this environment.

Pilates versus general exercise effectiveness on pain and functionality in non-specific chronic low back pain subjects.

Low back pain (LBP) is one of the most common causes of disability, and the Pilates method has been associated with improvements in symptoms. The purpose of this study was to assess the effectiveness of the Pilates method, when compared to general exercises, on pain and functionality after eight weeks (16 sessions, 2×/week) and a follow-up of three months, in subjects with non-specific chronic low back pain (NSCLBP). A randomised controlled trial composed of 22 subjects was proposed. Subjects were allocated into two groups: the Pilates group (PG) (n = 11) and the general exercise group (GEG) (n = 11). The PG protocol was based on the Pilates method and the GEG performed exercises to manage NSCLBP. There were no differences between the groups. When analysed over time, the GEG demonstrated improvements in functionality between baseline and the end of treatment (P = .02; Cohen'sd¯ = 0.34) and baseline and follow-up (P = .04; Cohen'sd¯ = 0.31). There were no differences between the Pilates and general exercises with regard to pain and functionality in NSCLBP subjects but general exercises were better than Pilates for increasing functionality and flexibility.