Objective To determine the benefits associated with brief inpatient rehabilitation for Covid-19 patients. Design Retrospective chart review. Setting A newly created specialized rehabilitation unit in a tertiary care medical center Participants Consecutive sample of the first 100 patients with Covid-19 infection admitted to rehabilitation. Intervention Inpatient rehabilitation for post-acute care Covid-19 patients Main Outcome Measures Measurements, at admission and discharge, comprised a Barthel Activities of Daily Living Index (including baseline value before Covid-19 infection), time to perform 10 sit-to-stands with associated cardio-respiratory changes, and grip strength (dynamometry). Correlations between these outcomes and the time spent in ICU were explored. Results Patient characteristics upon admission to rehabilitation were: men 66%, age 66±22 years, mean delay from symptom onset 20.4±10.0 days, BMI 26.0±5.4 kg/m 2 , hypertension 49%, diabetes 29%, with 26% having >50% pulmonary damage on CT-scans. Mean length of rehabilitation stay was 9.8±5.6 days. From admission to discharge, the Barthel index (/100) increased from 77.3±26.7 to 88.8±24.5 ( p <0.001), without recovering baseline values (94.5±16.2; p <0.001). There was a 37% improvement in sit-to-stand frequency (0.27±0.16 to 0.37±0.16 Hz; p <0.001), a 13% decrease in post-test respiratory rate (30.7±12.6 to 26.6±6.1; p =0.03), and a 15% increase in grip strength (18.1±9.2 to 20.9±8.9 kg; p <0.001). At both admission and discharge, Barthel score correlated with grip strength (rho=0.39-0.66; p <0.01), which negatively correlated with time spent in ICU (rho=-0.57 to -0.49, p <0.05). Conclusions Inpatient rehabilitation for Covid-19 patients was associated with substantial motor, respiratory and functional improvement, especially in severe cases, even though there remained mild persistent autonomy loss upon discharge. Following acute stages, Covid-19, primarily a respiratory disease, might convert into a motor impairment correlated with the time spent in intensive care.

Backgound: Metrics for movement smoothness include the number of zero-crossings on the acceleration profile (N0C), the log dimensionless jerk (LDLJ), the normalized averaged rectified jerk (NARJ) and the spectral arc length (SPARC). Sensitivity to the handedness and movement type of these four metrics was compared and correlations with other kinematic parameters were explored in healthy subjects. Methods: Thirty-two healthy participants underwent 3D upper limb motion analysis during two sets of pointing movements on each side. They performed forward- and backward-pointing movements at a self-selected speed to a target located ahead at shoulder height and at 90% arm length, with and without a three-second pause between forward and backward movements. Kinematics were collected, and smoothness metrics were computed. Results: LDLJ, NARJ and N0C found backward movements to be smoother, while SPARC found the opposite. Inter- and intra-subject coefficients of variation were lowest for SPARC. LDLJ, NARJ and N0C were correlated with each other and with movement time, unlike SPARC. Conclusion: There are major differences between smoothness metrics measured in the temporal domain (N0C, LDLJ, NARJ), which depend on movement time, and those measured in the frequency domain, the SPARC, which gave results opposite to the other metrics when comparing backward and forward movements.