SADDLE PRESSURE DISTRIBUTION IN CYCLING: COMPARISON AMONG SADDLES OF DIFFERENT DESIGN AND MATERIALS

This study compared saddle pressure distribution patterns in a group of experienced cyclists riding their own bicycle mounting different saddle models. Two traditional flat surface saddles incorporating different shock-absorbent materials in the perineal area and two innovative saddles with a hole in the perineal area were evaluated. The T-Scan system was utilised to measure the saddle pressure distribution. Each subject showed an individual pressure distribution pattern when using the same saddle. The use of the different saddles resulted in same significant changes in the saddle pressure amplitude and distribution pattern in all the subjects examined. In general, the flat surfaced saddles showed a more uniform pressure distribution with less pressure on the anterior part and more on the posterior part compared with the saddle with a perineal hole

Gait Initiation in Children with Rett Syndrome

Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait

Events Detection of Anticipatory Postural Adjustments through a Wearable Accelerometer Sensor Is Comparable to That Measured by the Force Platform in Subjects with Parkinson’s Disease

Out-of-the-lab instrumented gait testing focuses on steady-state gait and usually does not include gait initiation (GI) measures. GI involves Anticipatory Postural Adjustments (APAs), which propel the center of mass (COM) forward and laterally before the first step. These movements are impaired in persons with Parkinson’s disease (PD), contributing to their pathological gait. The use of a simple GI testing system, outside the lab, would allow improving gait rehabilitation of PD patients. Here, we evaluated the metrological quality of using a single inertial measurement unit for APA detection as compared with the use of a gold-standard system, i.e., the force platforms. Twenty-five PD and eight elderly subjects (ELD) were asked to initiate gait in response to auditory stimuli while wearing an IMU on the trunk. Temporal parameters (APA-Onset, Time-to-Toe-Off, Time-to-Heel-Strike, APA-Duration, Swing-Duration) extracted from the accelerometric data and force platforms were significantly correlated (mean(SD), r: 0.99(0.01), slope: 0.97(0.02)) showing a good level of agreement (LOA [s]: 0.04(0.01), CV [%]: 2.9(1.7)). PD showed longer APA-Duration compared to ELD ([s] 0.81(0.17) vs. 0.59(0.09) p < 0.01). APA parameters showed moderate correlation with the MDS-UPDRS Rigidity, Characterizing-FOG questionnaire and FAB-2 planning. The single IMU-based reconstruction algorithm was effective in measuring APAs timings in PD. The current work sets the stage for future developments of tele-rehabilitation and home-based exercises

Spatio-temporal parameters of the stride, arm ROM and phase shift of subjects with Parkinson disease and healthy subjects.

<p>Median values, non-outlier min-max, and levels of statistical difference (Mann-Whitney U-test or Matched pairs) are reported. Data refer at walking at different velocities unless otherwise specified.</p>*<p>p<0.05 (PD vs. HC); ** p<0.01 (PD vs. HC). BH = body height (mm). ROM = range of motion; Phase shift = temporal delay (%stride) between the positive peak (antero-posterior swing) of the wrist and the negative peak of malleolus; Stride = the period from initial contact of one foot and following initial contact of the same foot, is one gait cycle. Stance = gait phase when a foot is in contact with the ground, it begins with initial heel contact and ends with toe off.</p><p>For Parkinson patients, ipsilateral and contralateral refers to the more dopamine depleted hemisphere. For healthy controls, left hemibody refers conventionally to ipsilateral.</p

Surface-Electromyography-Based Co-Contraction Index for Monitoring Upper Limb Improvements in Post-Stroke Rehabilitation: A Pilot Randomized Controlled Trial Secondary Analysis

Persons post-stroke experience excessive muscle co-contraction, and consequently the arm functions are compromised during the activities of daily living. Therefore, identifying instrumental outcome measures able to detect the motor strategy adopted after a stroke is a primary clinical goal. Accordingly, this study aims at verifying whether the surface electromyography (sEMG)-based co-contraction index (CCI) could be a new clinically feasible approach for assessing and monitoring patients' motor performance. Thirty-four persons post-stroke underwent clinical assessment and upper extremity kinematic analysis, including sEMG recordings. The participants were randomized into two treatment groups (robot and usual care groups). Ten healthy subjects provided a normative reference (NR). Frost's CCI was used to quantify the muscle co-contraction of three different agonist/antagonist muscle pairs during an object-placing task. Persons post-stroke showed excessive muscle co-contraction (mean (95% CI): anterior/posterior deltoid CCI: 0.38 (0.34-0.41) p = 0.03; triceps/biceps CCI: 0.46 (0.41-0.50) p = 0.01) compared to NR (anterior/posterior deltoid CCI: 0.29 (0.21-0.36); triceps/biceps CCI: 0.34 (0.30-0.39)). After robot therapy, persons post-stroke exhibited a greater improvement (i.e., reduced CCI) in proximal motor control (anterior/posterior deltoid change score of CCI: -0.02 (-0.07-0.02) p = 0.05) compared to usual care therapy (0.04 (0.00-0.09)). Finally, the findings of the present study indicate that the sEMG-based CCI could be a valuable tool in clinical practice

Correlation between phase shift modulation at different gait velocities and DAT binding values of the putamen (A) and caudate nucleus (B).

<p>Full dots represent arms with reduced (<18°) ROM when walking at preferred gait speed. Empty dots shows arms with arm ROM within the normal range. When arm ROM was reduced, a positive correlation was found between upper-lower limb phase shift modulation and both DAT binding values of putamen (RSquare = 0.37, p = 0.01) and caudate nucleus (RSquare = 0.38, p = 0.01). Correlation lines for arms with normal ROM (>18°) are not shown.</p

ASA significantly correlated to the AI of DAT binding values of the putamen (see, Methods).

<p>ASA significantly correlated to the AI of DAT binding values of the putamen (see, Methods).</p

Supplementary Material, wair_data – Influence of the amount of body weight support on lower limb joints’ kinematics during treadmill walking at different gait speeds: Reference data on healthy adults to define trajectories for robot assistance

<p>Supplementary Material, wair_data for Influence of the amount of body weight support on lower limb joints’ kinematics during treadmill walking at different gait speeds: Reference data on healthy adults to define trajectories for robot assistance by Maurizio Ferrarin, Marco Rabuffetti, Elisabetta Geda, Silvia Sirolli, Alberto Marzegan, Valentina Bruno and Katiuscia Sacco in Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine</p

EMG recordings (RMS).

<p>Imb. = Imbalance; Unl. = Unloading; SOL = Soleus muscle; TA = Tibialis anterior muscle; p values refers to Wilcoxon-Mann-Whitney U Test.</p