EXPERIMENTAL ANALYSIS OF THE LUMBAR SPINE KINEMATICS

Pain-provoking disorders of the lumbar spine affect most of adult population and nearly everyone suffers from some of them during their lifetime. A common symptom of diseases, injuries or inevitable changes in the area of lumbar spine is known as the Low Back Pain (LBP). A chronic form of the LBP, called the Low Back Pain syndrome, is mostly caused by degenerative changes of intervertebral discs of the lowest intervertebral joints. The work was focused on in vitro analysis of the porcine lumbar spine kinematics. Two last neighbouring intervertebral joints without active tissue, L4/5 and L5/6, were used. The total number of fifteen cadaveric samples of porcine lumbar spine was involved. A unique loading mechanism was designed and constructed for the purposes of this study. Samples were loaded by flexion/extension movement within the physiological range of motion of ± 5°, in a quasi-static mode. The recording and analysing of the lumbar spine kinematics was realized by the motion capture camera system (Qualisys AB, Göteborg, Sweden). The results showed that the so-called instantaneous axis of rotation (IAR), or the corresponding instantaneous centre of rotation (ICR), was an adequate objective parameter for the assessment of the lumbar spine kinematics. Its position was comparable across all samples and situated very close to the spinal canal. For the purposes of this work, an altered artificial disc of a ball-and-socket type (ProSpon, Ltd., Kladno, Czech Republic) was used to study the kinematics of two neighbouring joints after the disc replacement in the area of a caudally situated one. The results of this comparative analysis showed a significant influence of the artificial disc on the kinematics of both, caudally situated joint, where the disc was implanted, and the adjacent one

Effect of strength training programs on front push kick dynamics and kinematics

Background and Study Aim: The general fitness requirements for any combat activity include the flexibility, speed, power, muscular endurance, aerobic capacity, muscular strength, agility, balance, coordination, and body composition. In addition, the development of these fitness component should support and not disrupt the development and practice of combat techniques The aim of this study was knowledge about the effects of two programs of strength training on front push kick dynamics and kinematics across different loading conditions (no-load up to 45kg of external load) in professional soldiers. Material and Methods: Sixteen professional military personnel were randomized into two groups who performed an 8-week intervention program focused either on functional training with a core emphasis (FCE: 26.8 ±10.1 years, 84.2 ±5.4 kg, 181.1 ±6.4 cm) or traditional strength preparation (TSP: 26.8 ±10.1 years, 84.2 ±5.4 kg, 181.1 ±6.4 cm). Both groups performed 5 front push kicks into a force plate across 5 different loading conditions and forces and kinematics were measured. Results: The main differences in the performance of the front push kicks after FCE were that impulse increased by 16% and the impact time of the front kicks were prolonged by 10% whereas after TSP the peak force was increased by 20% and the angular velocity of the knee by 13%. Both training programs promoted changes in the coordination of movement as quantified by principal component analysis. Conclusions: The FCE should be included in training close combat to increase impulse of the front push kick and TSP should be included to increase the peak force and the angular velocity of the knee. The combination of FCE and TSP should be used in training as both could improve kicking performance

Principal component analysis can be used to discriminate between elite and sub-elite kicking performance

Contemporary descriptions of motor control suggest that variability in movement can be indicative of skilled or unskilled performance. Here we used principal component analysis (PCA) to study the kicking performance of elite and sub-elite soldiers who were highly familiar with the skill, in order to compare the variability in the first and second principal components. The subjects kicked a force plate under a range of loaded conditions, and their movement was recorded using optical motion capture. The first principal component explained > 92% of the variability across all kinematic variables when analysed separately for each condition and both groups and explained more of the variation in the movement of the elite group. There was more variation in the loading coefficient of the first principal component for the sub-elite group. In contrast, for the second principal component there was more variation in the loading coefficient for the elite group, and the relative magnitude of the variation was greater than for the first principal component for both groups. These results suggest that the first principal component represented the most fundamental movement pattern and there was less variation in this mode for the elite group. In addition, more of the variability was explained by hip than knee angle entered when both variables were entered into the same PCA which suggests that the movement is driven by the hip

Kinematic Determinants of Front Kick Dynamics Across Different Loading Conditions

ABSTRACT Introduction The efficiency of front kick is related to the kicking technique. Thus, the aim of this study was to find the kinematic determinants of front kick dynamics across different performance and loading levels (no load to 45-kg load). Materials and Methods Twenty-four elite and sub-elite professional military personnel (26.8 ± 10.1 years, 84.2 ± 5.4 kg, 181.1 ± 6.4 cm) performed six front kicks into a force plate across five different loading conditions. Three-dimensional kinematics of the kicks was quantified and included velocity of the hip (Vhip), velocity of the knee (Vknee), velocity of the shoulder (Vshoulder), velocity of the foot (Vfoot), angular velocity of the knee (AVknee), and angular velocity of the hip (AVhip). Results The main kinematic differences between the two groups were that the sub-elite group had an increased kick time for all loading conditions (P < .001) and a lower Vfoot (P = .05) and a decreased Vhip and Vshoulder (P < .05) in the highest load condition. Vhip and AVhip were the best predictors (up to R2 = 0.58; P = .020) of peak force and impact force during no-load or loaded kicking at the elite level. Typical predictors of impulse in the elite group were AVhip, Vhip, and Vshoulder and those in the sub-elite group were AVknee and Vfoot. Conclusions The kinematic variables provide good predictions of kicking dynamics; however, the best predictor varies with the loading conditions and performance levels. Hip motion is the main differentiating factor

Patellofemoral pain syndrome assessed by Lysholm score, radiological and biorheometric measurements.

The aim of In this study was to verify the relationship among clinical indicators of patellofemoral pain syndrome (PFPS) and the results of modifying radiological investigation. Previous research suggests that there is a poor association between them. Therefore we have employed a technique for the functional evaluation of PFPS based on measuring the stiffness of the knee joint during passive flexion (biorheometry). The correlation between clinical examination and a standardized Lysholm score, radiological and biorheometric measures was investigated in the 28 knee joints of 14 subjects exhibiting clinical features of PFPS. A modified axial radiological projection of the patellofemoral articulation in 90° of flexion provided the parameters quantifying the anatomical - morphological arrangement of the patellofemoral joint. The biorheometric properties of the knee were evaluated using a custom made measuring apparatus during passive flexion and extension of the knee. Our results confirm that the link between the clinical findings and the X-ray imaging examinations was not evident. On the contrary, the biorheometric examination proved to correlate well with the clinical symptoms of PFPS. Parameters were identified which can characterize the biorheograms of people suffering PFPS. Analysis of the relationship among the clinical, radiological and biorheometric examinations leads to the recommendation that biorheometric examination is an effective method for the objective assessment of PFPS