Isokinetic Identification of Knee Joint Torques before and after Anterior Cruciate Ligament Reconstruction.

The aim of this study was to evaluate the serial change of isokinetic muscle strength of the knees before and after anterior cruciate ligament reconstruction (ACLR) in physically active males and to estimate the time of return to full physical fitness. Extension and flexion torques were measured for the injured and healthy limbs at two angular velocities approximately 1.5 months before the surgery and 3, 6, and 12 months after ACLR. Significant differences (p ≤ 0.05) in peak knee extension and flexion torques, hamstring/quadriceps (H/Q) strength ratios, uninvolved/involved limb peak torque ratios, and the normalized work of these muscles between the four stages of rehabilitation were identified. Significant differences between extension peak torques for the injured and healthy limbs were also detected at all stages. The obtained results showed that 12 months of rehabilitation were insufficient for the involved knee joint to recover its strength to the level of strength of the uninvolved knee joint. The results helped to evaluate the progress of the rehabilitation and to implement necessary modifications optimizing the rehabilitation training program. The results of the study may also be used as referential data for physically active males of similar age

Modeling record scores in the snatch and its variations in the long-term training of young weightlifters.

The primary aim of the current study was to determine the time curves of changes in the record scores in the snatch and its variations during a two-year training cycle in young weightlifters. This study also aimed at assessing the ratios between these scores and at predicting the snatch record scores at the end of the subsequent annual training macrocycle. The final purpose was to compare the record scores with the isometric peak torque values of the trunk and knee extensors. The study involved 16 weightlifters who were tested seven times at three-month intervals. The overall mean ratios of the record scores in the hang snatch to those in the snatch and the record scores in the hang power snatch to those in the snatch were approximately constant and amounted to 0.95 and 0.79, respectively. The overall mean ratio between the scores in the power snatch to those in the snatch was approximately 0.88. Statistically significant differences (p < 0.05) between the individual time trajectories of record scores in the snatch and its derivatives were identified in two consecutive annual training macrocycles. The error in predicting record results at the end of the following annual training macrocycle was 6.7 ± 4.7% or 8.1 ± 3.4% depending on the way the measurement data were modeled. The results of the study also indicate that the measurements of the isometric peak torque of the trunk extensors performed in laboratory conditions can be useful in diagnosing the strength capacity of young weightlifters

Metody badania sznurowadeł obuwniczych ze względu na odporność na ścieranie i samoistne rozwiązywanie

In this paper, two types of footwear laces research were undertaken. The first was connected with abrasion resistance and the second with the displacement force at the knot. The abrasion resistance was registered by the level of abrasion for standard eyelet. The displacement force was measured with the use of a tensile test machine, where the force and extension were registered. As a criterion of test evaluation, the maximum force was established when the knot was untied. The research was conducted for a set of different types of shoelaces (differing in shape, structure and raw materials). The evaluation criteria proposed can be used in order to determine the raw materials and optimal construction of shoelaces. From the user’s point of view, the measures identified i. e. the displacement force in the knot (Fpw) and abrasion resistance (Ks) are the most important factors.W pracy przedstawiono dwie metody badań sznurowadeł obuwniczych, dotyczące odporności na ścieranie i siły przesuwu w węźle. Odporność na ścieranie badano na specjalnie wykonanym stanowisku, w którym elementem ścierającym było standardowe oczko obuwnicze. Badania siły przesuwu sznurowadła w węźle wykonywano na zrywarce wyposażonej w urządzenie rejestrujące siłę i wydłużenie. Jako kryterium oceny przyjęto maksymalną siłę, przy której nastąpiło rozwiązanie węzła sznurowadła. Materiał badań stanowiły sznurowadła obuwnicze różniące się kształtem (strukturą) wykonane z różnych surowców. Zaproponowane kryteria oceny pozwalają na optymalne dobranie surowców i konstrukcji sznurowadeł obuwniczych. Wyznaczane wskaźniki tj. siła przesuwu sznurowadła w węźle (Fpw) i współczynnik odporności na ścieranie (Ks) stanowią najbardziej istotne wskaźniki z punktu widzenia użytkownika

Variability of shoulder girdle temperature in the initial phase of the snatch in weightlifting

The identification of activation, synchronization and work of individual muscles in the subsequent stages of lifting weights is interesting for researchers and trainers. Unfortunately, the existing methods of research do not provide such possibilities. Such information could be gathered from infrared measurements as they are non-invasive and can be carried out without the direct involvement of the weightlifter. The purpose of the study was to analyse temperature changes in the shoulder girdle in the first phase of the snatch in weightlifting. Methods: The study involved 11 weightlifters who competed in two weight categories, 94 and 105 kg, during the World University Championships in 2018. The performance of the snatch was recorded using a thermographic camera in three consecutive attempts. We analysed the temperature changes in the left and right shoulder girdles in the two initial stages of the snatch. Statistical analysis of empirical data was performed using linear mixed effects models. Results: Statistically significant temperature increases were found from the moment of gripping the barbell to the moment it was pulled. These effects were different in individual weightlifters, but did not depend on the attempt or the side of the body. Conclusions: Temperature increases in the initial phase of the snatch are most likely the result of activating successive motor units in order to perform the effort needed to pull the barbell and cause it to accelerate. The results obtained confirm that thermography is an effective method of monitoring muscle activity in weightlifting, which may be useful for coaches and athletes

H/Q ratio in consecutive stages of rehabilitation.

<p>H/Q ratio in consecutive stages of rehabilitation.</p

Gravitationally corrected knee flexion torque and angular acceleration of the knee attachment.

<p>Gravitationally corrected knee flexion torque and angular acceleration of the knee attachment.</p

Boletín de Segovia: Número 153 - 1844 diciembre 17

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200