Search

Core-specific sensorimotor exercises are proven to enhance neuromuscular activity of the trunk. However, the influence of high-intensity perturbations on training efficiency is unclear within this context. Sixteen participants (29 ± 2 yrs; 175 ± 8 cm; 69 ± 13 kg) were prepared with a 12-lead bilateral trunk EMG. Warm-up on a dynamometer was followed by maximum voluntary isometric trunk (flex/ext) contraction (MVC). Next, participants performed four conditions for a one-legged stance with hip abduction on a stable surface (HA) repeated randomly on an unstable surface (HAP), on a stable surface with perturbation (HA + P), and on an unstable surface with perturbation (HAP + P). Afterwards, bird dog (BD) was performed under the same conditions (BD, BDP, BD + P, BDP + P). A foam pad under the foot (HA) or the knee (BD) was used as an unstable surface. Exercises were conducted on a moveable platform. Perturbations (ACC 50 m/sec 2 ;100 ms duration;10rep.) were randomly applied in the anterior-posterior direction. The root mean square (RMS) normalized to MVC (%) was calculated (whole movement cycle). Muscles were grouped into ventral right and left (VR;VL), and dorsal right and left (DR;DL). Ventral-Dorsal and right-left ratios were calculated (two way repeated-measures ANOVA;α = 0.05). Amplitudes of all muscle groups in bird dog were higher compared to hip abduction (p ≤ 0.0001; Range: BD: 14 ± 3% (BD;VR) to 53 ± 4%; HA: 7 ± 2% (HA;VR) to 16 ± 4% (HA;DR)). EMG-RMS showed significant differences (p < 0.001) between conditions and muscle groups per exercise. Interaction effects were only significant for HA (p = 0.02). No significant differences were present in EMG ratios (p > 0.05). Additional high-intensity perturbations during core-specific sensorimotor exercises lead to increased neuromuscular activity and therefore higher exercise intensities. However, the beneficial effects on trunk function remain unclear. Nevertheless, BD is more suitable to address trunk muscles. [ABSTRACT FROM AUTHOR]

Background: Elderly patients are a growing population in cardiac rehabilitation (CR). As postural control declines with age, assessment of impaired balance is important in older CR patients in order to predict fall risk and to initiate counteracting steps. Functional balance tests are subjective and lack adequate sensitivity to small differences, and are further subject to ceiling effects. A quantitative approach to measure postural control on a continuous scale is therefore desirable. Force plates are already used for this purpose in other clinical contexts, therefore could be a promising tool also for older CR patients. However, in this population the reliability of the assessment is not fully known.Research Question: Analysis of test-retest reliability of center of pressure (CoP) measures for the assessment of postural control using a force plate in older CR patients.Methods: 156 CR patients (≥75 years) were enrolled. CoP measures (path length (PL), mean velocity (MV), and 95% confidence ellipse area (95CEA)) were analyzed twice with an interval of two days in between (bipedal narrow stance, eyes open (EO) and closed (EC), three trials for each condition, 30 s per trial), using a force plate. For test-retest reliability estimation absolute differences (Δ: T0-T1), intraclass correlation coefficients (ICC) with 95% confidence intervals, standard error of measurement and minimal detectable change were calculated.Results: Under EO condition ICC were excellent for PL and MV (0.95) and good for 95CEA (0.88) with Δ of 10.1 cm (PL), 0.3 cm/sec (MV) and 1.5 cm2 (95CEA) respectively. Under EC condition ICC were excellent (≥ 0.95) for all variables with larger Δ (PL: 21.7 cm; MV: 0.7 cm/sec; 95CEA: 2.4 cm2).Significance: In older CR patients, the assessment of CoP measures using a force plate shows good to excellent test-retest reliability. [ABSTRACT FROM AUTHOR]