Background: Low Back Pain (LBP) is a frequent, very common, and costly health problem. LBP, which occurs during pregnancy, may become a lifelong problem. The aim of this study was to determine the risk factors associated with LBP in pregnant women. Methods: The study included 1510 pregnant women. A questionnaire assessing demography, lifestyle, prevalence, and characteristics was designed and used in the study. Pain intensity was assessed with the VAS (Visual Analogue Scale). The RMDQ (Roland Morris Disability Questionnaire) was used to assess the effect that low back pain had on the functional capacity of a pregnant woman. Middle (thoracic) and low back pain disability was measured with the help of the ODI (Oswestry Disability Index) questionnaire. Results: The study confirmed that lying/sleeping (49.6%) and sitting positions (38.7%) as well as walking (37.2%) are the most significant factors causing LBP. It was also found that women who had not engaged in physical activity were more likely to experience LBP. Conclusions: Predisposing factors for LBP in pregnancy are LBP in previous pregnancies, back pain during menstruation, a younger age and a lack of physical activity. Most women in pregnancy with LBP experienced minimal and mild disability.

Although it is well-established that exoskeletons as robots attached to the extremities of the human body increase their strength, limited studies presented a computer and mathematical model of a human leg hydraulic exoskeleton based on anthropometric data. This study aimed to examine lower limb joint angles during walking and running by using Inertial Measurement Units. The geometry and kinematic parameters were calculated. Twenty-six healthy adults participated in walking and running experiments. The geometric model of a human leg hydraulic exoskeleton was presented. Joint angle data acquired during experiments were used in the mathematical model. The position and velocity of exoskeleton actuators in each phase of movement were calculated using the MATLAB package (Matlab_R2017b, The MathWorks Company, Novi, MI, USA). The highest velocity of the knee actuator during walking and running was in the swing phase, 0.3 and 0.4 m/s, respectively. For the ankle and hip joints, the highest velocity of actuators occurred during the push-off phase. The results with 26 healthy subjects demonstrated that the system's compliance can be effectively adjusted while guiding the subjects walking in predefined trajectories. The developed mathematical model makes it possible to determine the position of lower limb segments and exoskeleton elements. The proposed model allows for calculating the position of the human leg and actuators’ characteristic points.

Background: the goal of the study is to ascertain the influence of discopathy in the lumbosacral (L-S) segment on the gait parameters. The inertial sensors are used to determine the pathologic parameters of gait. Methods: the study involved four patients (44, 46, 42, and 38 years). First, the goal of the survey was to analyze by a noninvasive medical test magnetic resonance imaging (MRI) of each patient. Next, by using inertial sensors, the flexion-extension of joint angles of the left and right knees were calculated. The statistical analysis was performed. The wavelet transform was applied to analyze periodic information in the acceleration data. Results: in the patients with discopathy, the amount of knee flexion attained during stance phase is significantly lower than that of normal (health side), which could indicate poor eccentric control or a pain avoidance mechanism. The biggest differences are observed in the Initial Swing phase. Bending of the lower limb in the knee joint at this stage reaches maximum values during the entire gait cycle. Conclusions: It has been difficult to quantify the knee angle during gait by visual inspection. The inertial measurement unit (IMU) system can be useful in determining the level of spine damage and its degree. In patients in the first stages of the intervertebral disc disease who may undergo conservative treatment, it may also partially delay or completely exclude the decision to perform a complicated imaging examination which is MRI, often showing a false positive result in this phase of the disease.

(1) Background: Low Back Pain is a major health concern. Pregnancy-related lower back pain is a common complaint among women. The aim of this study was to determine the influence of pregnancy history on the occurrence and profile of pain in the lower spine. (2) Methods: The diagnosis of Lower Back Pain during pregnancy was based on the authors’ questionnaire, Visual Analogue Scale (VAS), Oswestry Disability Index and Roland Morris Disability Questionnaire. The research group consisted of 1112 women who were students or came for various reasons to the Gynecology and Obstetrics Clinical Hospital of Poznan University of Medical Sciences and completed the questionnaires. Patients were divided into two groups. The first group consisted of women who had never been pregnant (never-pregnant, n = 872 (78.4%), and the second group consisted of women who had been pregnant at least once in their lives (ever-pregnant, n = 240 (21.6%)). (3) Results: In the never-pregnant and the ever-pregnant women, respectively, the intensity of pain was 4.6 ± 1.6 and 5.0 ± 2.0 on the VAS scale, the degree of disability on the Oswestry Disability Index Questionnaire was 5.0 ± 3.9 and 5.5 ± 4.4, while the impact of pain on functioning on the Roland Morris Disability Questionnaire was 3.9 ± 3.1 and 3.9 ± 3.3. There were no significant differences (Mann-Whitney U test) between the studied groups in the parameters tested. (4) Conclusions: Pregnancy is a risk factor for back pain during pregnancy, but one year or more after pregnancy the occurrence of back pain is similar to that in women who have never been pregnant.

Exoskeletons are the mechanical systems whose operation is carried out in close cooperation with the human body. In this paper, the authors describe a mathematical model of the hydraulic exoskeleton of a lower limb. The coordinates of characteristic points of the exoskeleton in the sagittal plane as a function of user height are presented. The mathematical models, kinematics, and kinetics equations were determined. The masses of the actuators and their dimensions were selected based on catalog data. The force distribution in the wearable system during the squat is shown. The proposed models allowed us to determine the trajectory of individual points of the exoskeleton and to determine the forces in hydraulic cylinders that are necessary to perform a specific displacement. The simulation results show that the joint moments depend linearly on actuator forces. The dynamics equations of the wearable system are non-linear. The inertia of the system depends on the junction variables and it proves that there are dynamic couplings between the individual axes of the exoskeleton.