BackGROUND: Parkinson’s disease (PD) is a complex, progressive neurodegenerative disorder known to negatively impair patient gait. Therefore, with gait and vertical GROUND REACTION FORCE (VGRF) data, an association can be made between the data and Parkinson’s disease. Methods: Data from 146 participants, 93 with Parkinson’s disease and 73 without Parkinson’s disease was obtained from a PhysioNet database for use in this article. A Fourier Analysis and several support vector machine learning models were computed in MATLAB to classify whether an individual had Parkinson’s disease. Results: From the Fourier analysis, it was determined that a statistically significant difference was present between the VGRF data of individuals with and without Parkinson’s disease. Additionally, it was found that a Minimum Classification Error Optimized SVM machine learning model using Bayesian statistics was able to classify individuals with Parkinson’s disease using VGRF data at an accuracy of 67. 1%, and sensitivity of 80. 43%. Conclusion: Therefore, it can be determined that vertical GROUND REACTION FORCE can predict Parkinson’s Disease with considerable accuracy which could be improved with an increased number of participants.

BackGROUND: Forward head posture is one of the most prevalent abnormal postures in patients with neck disorders. The aim of this study was to evaluate the effects of forward head posture on gait GROUND REACTION FORCE characteristics in children. Methods: Twelve children with forward head posture (age: 11. 8± 1. 3 years) and sixteen healthy control children (age: 11. 7± 1. 4 years) volunteered to participate in this study. Each participant was asked to walk 10 m in six trials with self-selected speed. The GROUND REACTION FORCE was measured by two Kistler FORCE Platforms at a frequency of 1000 Hz. MANOVA test ((version 16, SPSS Inc, Chicago, Il)) was used for between group comparisons. Results: In the non-dominant limb, the medio-lateral GROUND REACTION FORCE during push off phasein the forward head group was greater than that in the healthy group by 22. 1% (P=0. 049). In the dominant limb, time to peak for vertical GROUND REACTION FORCE during heel contact(by 13. 7%; P=0. 015) and push off(by 14. 2%; P=0. 004), mediolateral GROUND REACTION FORCE during heel contact (by 46. 0%; P=0. 006) and push off (by 15. 1%; P=0. 039) in the forward head group were significantly lower than those in the healthy group. Vertical loading, peak positive and negative free moment, and impulses in all axes were similar in the healthy and the forward head groups (P>0. 05). Conclusion: Overall, the results reveal that gait GROUND REACTION FORCE components (especially time to peak for GROUND REACTION FORCEs) in forward head children may have clinical importance for the improvement of walking mechanics of these individuals. Rehabilitation protocols should be designed to increase time to reach peak GROUND REACTION FORCEs and decrease medio-lateral GROUND REACTION FORCE in forward head children during walking.

The characteristics of vertical GROUND REACTION FORCE (VGRF) gait patterns in children with autism spectrum disorders (ASD) are poorly understood. The purpose of this study was to identify VGRF gait features that discriminate between children with ASD and the peer control group. The VGRF data were obtained from 30 children with ASD and 30 normal healthy children aged 4 to 12 years. A three-dimensional motion analysis system with eight cameras and two FORCE plates were used to collect VGRF data while subjects performed self-selected speed of barefoot walking. Parameterization techniques were applied to VGRF waveforms to extract the VGRF gait features. Mean significant differences between the two groups were tested using independent samples t-test and Mann-Whitney U test. Significant group differences were found for four VGRF gait features. Results indicated that children with ASD exhibited a significant reduction of the second peak of VGRF, earlier relative time to the occurrence of the second peak of VGRF, lower push-off rate, and higher peak ratio of the two VGRF peaks during normal speed of walking. These prominent differences showed that children with ASD had difficulties in supporting their body weight during terminal stance phase and these conditions affect the gait instability. The findings of this study develop further understanding of VGRF gait patterns that significantly differentiate between children with ASD and the peer control groups.

ankle movements, jumping or landing, where peroneal muscles are fatigued. Changes in GROUND REACTION FORCE (GRF) parameters may also be related to this injury. The present study aimed to assess the effects of peroneal muscles fatigue on GRF profile during lateral hop landing. Materials and Methods: Twenty-five recreationally active healthy males performed a lateral hop on a FORCE plate before and after a fatigue intervention by a Biodex dynamometer using an isometric eversion at 40% of maximal voluntary isometric contraction until eversion torque decreased to 50% of its initial value. A FORCE plate and an EMG system were used to collect data during lateral hop landing. Results: Fatigue was confirmed by a significant fall in median frequency (P<0. 05). Mean of the normalized peak GRF in the vertical direction, mean of the normalized impulse of the GRF in the vertical direction, and means of the time to peak GRF in the vertical and mediolateral directions decreased significantly after fatigue (P<0. 05). Conclusion: If the peroneal muscles are fatigued, a much more load may transfer to the vertical direction during landing, although the vulnerable part of the ankle is situated on the mediolateral direction.