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The Influence of Therapeutic Training on Changes in Selected Biomechanical Variables After an Anterior Cruciate Ligament Reconstruction

100%
Jarocka M., Czaplicki A.
Polish Journal of Sport and Tourism
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2013
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vol. 20
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issue 1
13-18
EN
Introduction. The number of arthroscopic reconstructions of the anterior cruciate ligament (ACL) has been increasing not only among competitive athletes, but also among recreational athletes. The monitoring of the rehabilitation process in order to determine a safe time to return to the pre-injury activity is thus of great practical importance. The aim of this paper is to analyse the changes in selected biomechanical variables which occur after the therapeutic training following an anterior cruciate ligament reconstruction. Materials and methods. Twenty nine males (age 27.3 ± 5.7 years) after the anterior cruciate ligament reconstruction participated in the study. A quadruple-stranded semitendinosus/gracilis graft was used for the reconstruction. The biomechanical evaluation of the rehabilitation process was provided by an isokinetic dynamometer Biodex System Pro-3 working at speeds of 60 deg/s and 180 deg/s during testing the knee extensor and flexor muscles. In the case of an injured limb, the absolute peak torque, relative peak torque, average power and hamstring/ quadriceps (H/Q) ratio were determined. In addition, the values of flexor and extensor torques for healthy and injured limbs were compared. The study was carried out in four stages: before the surgery, three, six and twelve months after the surgery. Results and analyses. The results showed significant differences in each value between various stages of the biomechanical rehabilitation process of the knee. The applied therapeutic training influenced significantly the changes in the values of the tested variables. The results have confirmed that the biomechanical measurements can be treated as a supplementation to the clinical evaluation of the patient after ACL reconstruction. They may also be used for the optimisation of the therapeutic training.
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Inverse Dynamics and Artificial Neural Network Applications in Gait Analysis of the Disabled Subjects

100%
Wit A., Czaplicki A.
Human Movement
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2008
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vol. 9
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issue 2
93-102
EN
The aim of this study is to review the achievements of the mathematical modeling of muscles force contribution during walking. In order to determine the contributions of individual muscles to the net force or net muscle torque at a given joint, the external forces acting on lower extremity joints during gait ought to be identified. The solution of this problem, called in biomechanics the inverse dynamics, is now regarded as a classical method of movement modelling. In the hypothesis put forward in this paper, it is considered if the artificial neural network method could be applied to the muscle contraction prediction during gait analysis in normal and disabled subjects. Artificial neural network (ANN) is an artificial intelligence method used in mathematical modelling and its applications in diverse areas, especially in biology and medicine, are steadily progressing. The achievements and possibilities of ANN in biomechanics were presented previously by others authors. For example, Liu and Lockhart [13] attempted at creating a network capable of reproducing muscle forces during gait from EMG signals recorded in working muscles. The objective of our study was to make use of the experience gained in the construction of ANN and to apply advanced mathematical procedures to identical experimental conditions of gaint analysis.
3
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Effect of Additional Load on Power Output during Drop Jump Training

81%
Makaruk H., Sacewicz T., Czaplicki A., Sadowski J.
Journal of Human Kinetics
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2010
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vol. 26
31-37
EN
Plyometrics can be an effective way of improving power performance in many sports. The purpose of this study was to examine the effects of additional loading on power during drop jump training. Forty-two untrained physical education students with plyometric training background participated in a six-week training 3 times a week. Subjects were randomized to one of three training groups: without (FREE) and with a weight vest (VEST; 5% body weight), and a control group (CON). Pretraining and post-training measures of concentric peak power (PP), force (Fpp) and velocity (υPP) at peak power and, in addition, time between eccentric and concentric peak power (tPPEC) were analyzed in a countermovement jump (CMJ) and a drop jump (DJ) from a height of 0.3 m. The FREE and VEST groups considerably improved PP in CMJ (p < 0.05), but υPP significantly increased (p < 0.05) and tPPEC significantly decreased (p < 0.05) only in the FREE group. The enhancement of PP and υPP was only demonstrated by the FREE group in DJ. The FREE group significantly decreased (p < 0.05) and the VEST group significantly increased (p < 0.05) tPPEC in DJ. It can be concluded that using additional load during drop jump training does not produce superior gains in power output when compared to a traditional drop jump training program.
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