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1

Ratios of torques of antagonist muscle groups in female soccer players

Struzik A., Siemieński A., Bober T., Pietraszewski B.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 1

153--158

EN

An increase in the value of the hamstring-to-quadriceps (H/Q) ratio with an increase in angular velocity may effectively prevent injuries of the back of the thigh. Previous studies have found that the conventional H/Q ratio was unaltered along with an increasing angular velocity in females. Therefore, this study aimed to investigate the relationships between the conventional H/Q ratio and angular velocity in a group of female soccer players. Methods: The study was carried out on a group of 16 female soccer players (age: 20.7 ± 3.9 years, body height: 166.1 ± 5.8 cm, body mass: 58.4 ± 6.2 kg, training experience: 8.8 ± 4.1 years). Measurements of peak torque of extensors and flexors of the knee joint under static conditions and under isokinetic conditions (at angular velocities of 30°/s, 60°/s, 90°/s and 120°/s) were carried out using a Biodex dynamometer. Results: There was a statistically significant increase in the conventional H/Q ratio with an increase in angular velocity. These differences occurred between measurements at angular velocities of 0°/s and 30°/s, and 30°/s and 60°/s. Conclusions: As previously found for males, an increase in conventional H/Q ratio with increased angular velocity was also present in this group of female players. This phenomenon should reduce the number of injuries of the muscles of back of the thigh. Coaches should pay attention to increasing the level of strength in the group of knee joint flexor muscles so as to make the value of the H/Q ratio appropriately high and increasing with increasing angular velocity.

2

Lower extremity power in female soccer athletes : a pre-season and in-season comparison

Pietraszewski B., Siemieński A., Bober T., Struzik A., Rutkowska-Kucharska A., Nosal J., Rokita A.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 3

129--135

EN

Purpose: Lower extremity power is an important physical capacity of a soccer athlete. Power represents, and can be modified by, the training of strength and speed. Pre-season and in-season training differs in the relative emphasis on these two quantities. It is nevertheless desirable that the mechanical power remain the same or become higher during the in-season period. The purpose of this study was to identify changes in quantities related to “explosive strength” and to check whether, in collegiate female soccer players, pre- and inseason lower extremity power will remain unaltered. Methods: Twenty collegiate female soccer players, representing all field positions, participated. Lower extremity power was assessed by a series of drop jumps executed from four different heights (15, 30, 45, and 60 cm). Mechanical power was calculated using subject’s mass, jump height, and acceleration due to gravity. This value was further normalized by body mass of each athlete to obtain the relative (or normalized) mechanical power. Results: The normalized lower extremity mechanical power was highest when landing from the 30 cm height for both pre- and inseason periods. However, contrary to expectations, it turned out lower during the in-season than during the pre-season test, even though no significant differences were found between the corresponding jump heights. Conclusions: It is concluded that altered, perhaps inadequate, training strategies were employed during the in-season period. Besides, advantages of adding the relative mechanical power as a season readiness indicator are underlined compared with relying on the jump height alone.

3

Balance disorders caused by running and jumping occurring in young basketball players

Struzik A., Zawadzki J., Pietraszewski B.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 2

103--109

EN

Purpose: Body balance, as one of the coordination abilities,is a desirable variable for basketball players as regards the necessity of efficient responses in constantly changing situations on a basketball court. The aim of this study was to check whether physical activity in the form of running and jumping influences variables characterizing the process of keeping body balance of a basketball player in the standing position. Methods: The research was conducted on 11 young basketball players. The measurements were taken with a Kistler force plate. Apart from commonly registered COP displacements, an additional variable describing the process of keeping body balance by a basketball player was ankle joint stiffness on the basis of which an “Index of Balance–Stiffness” (IB-S) was created. Results: Statistically significant differences were obtained for the maximum COP displacements and ankle joint stiffness between measurements of balance in the standing position before and after the employed movement tasks whereas there were no statistically significant differences for the aforementioned variables describing the process of keeping balance between measurements after running and after jumping. Conclusions: The research results indicate that the employed movement activities brought about significant changes in the process of keeping balance of basketball player in the standing position which, after the run performed, remain on a similar level to the series of jumps being performed. The authors attempted to establish an index based on the stiffness which yields a possibility to perceive each basketball player as an individual person in the process of keeping balance.

4

Evaluation of selected biomechanical parameters in female team sports players

Pietraszewski B., Struzik A.

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 4

103--108

EN

The aim of this research was to evaluate the biomechanical parameters of lower limbs and their influence on height of vertical jump. The research was conducted on a group of females practicing basketball and volleyball. The following equipment was used during the experiment: a force plate by Kistler, a Biometrics electrogoniometer and a specially designed chair to measure static torque by OPIW Opole. The results indicated that the jumping abilities of the examined athletes were poor. No statistically significant correlations were observed between knee static torque and heights of vertical jumps: CMJ and DJ. The authors suggest modification of the McClymont index (RSI) to evaluate the selection of platform height during plyometric training. Such modification would enable better choice of loads and better training control of the subject.

5

Three-dimensional human gait pattern - reference data for normal men

Pietraszewski B., Winiarski S., Jaroszczuk S.

Acta of Bioengineering and Biomechanics

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2012

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Vol. 14, no. 3

9-16

EN

The aim of this research was to establish a kinematic pattern of adult gait for motion analysis system BTS Smart-E used in the research conducted in the Laboratory of Biomechanical Analysis, University School of Physical Education, Wrocław. This research presents the results of gait patterns for a group of 17 adult males for three speed levels: high (1), preferred (2), and low (3). Subject's sex, age and speed of gait are to be considered in the kinematic normal gait pattern. No statistically significant differences were observed between the right and the left limb. However, differences between the high, preferred and low gait speed were noticeable. An increase in gait speed was related to the change in the angular range of motion in the hip, knee and ankle joints sagittal plane. The range of motion in joints mostly increased with the subjects' speed. No significant differences between the range of motion and speed were observed in the ankle joint.

6

Relative power of the lower limbs in drop jump

Pietraszewski B., Rutkowska-Kucharska A.

Acta of Bioengineering and Biomechanics

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2011

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Vol. 13, no. 1

13-18

EN

The purpose of this paper was to determine the power produced by the lower limbs in the take-off phase in drop jumps (DJ) and the correlation between the power and load measured by dropping height after take-off. The research group (N = 17) contained students practicing football, volleyball, basketball, athletics, high jump, swimming and fencing. The individual characteristics "power-load" of the players and the observation of the changes during the training process enable the coaches to choose precise loads and at the same time to improve the training. The criterion of choosing loads in the plyometric training may be relative power output of lower limbs referred to the DJ height. While the condition allowing player to perform this type of training may depend on obtaining greater power in drop jump than in counter movement jump.

7

Poziom rozwijanego statycznego momentu siły a wysokość skoku CMJ studentów AWF we Wrocławiu

Struzik A., Pietraszewski B.

Aktualne Problemy Biomechaniki

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2010

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z. 4

179--184

PL

W pracy poszukiwano związku między statycznym momentem siły prostowników i zginaczy stawu kolanowego (sumy prostowników i sumy zginaczy) a wysokością skoku CMJ. Rejestracji sił reakcji podłoża dokonano używając platformy dynamometrycznej firmy Kistler i oprogramowania BioWare. Badania przeprowadzono na grupie 30 studentów IV roku AWF we Wrocławiu w Pracowni Analiz Biomechanicznych. Badanymi były osoby uprawiające sport wyczynowo od minimum 5 lat. Badania miały na celu ocenę własności biomechanicznych (mierzonych w działaniach statycznych i dynamicznych) kończyn dolnych człowieka.

EN

The purpose of the research was to determine the relationship between the static moment of force of knee joint flexors and extensors (sum of flexors and sum of extensors) and the height of CMJ jump. Dynamometric Kistler plate and BioWare software were applied to record the ground reaction force. 30 University School of Physical Education students participated in the study. The research was conducted in the Laboratory of Biomechanical Analysis in Wroclaw. Subjects have been performing professional sport no less than 5 years. The purpose of the research was to assess the biomechanical properties of the lower limbs (measured during static and dynamic exercises).

8

Badanie zależności między statycznym momentem siły a wysokością skoku pionowego z zamachem ramion (CMJ) przy uzyciu nowoczesnych urządzeń pomiarowych

Struzik A., Pietraszewski B.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2010

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Vol. 16, nr 4

346-350

PL

Celem pracy było znalezienie związku między statycznym momentem siły prostowników i zginaczy stawu kolanowego (sumy prostowników i sumy zginaczy) a wysokością skoku. Rejestracji sił reakcji podłoża dokonano, używając platformy piezoelektrycznej firmy Kistler i oprogramowania BioWare. Badania przeprowadzono na grupie osób uprawiających sport wyczynowo od minimum 5 lat. Miały one na celu ocenę właściwości biomechanicznych (mierzonych w działaniach statycznych i dynamicznych) kończyn dolnych człowieka.

EN

The purpose o f examination was t o d e t e r m i n e t h e relationship between static moment of force of knee joint flexors and exiensors (sum of flexors and extensors) and the height of CMJ jump. Pjezoelectric Kistler plate and BioWare software were applied to record the ground reaction force. 30 University Schooi of Physical Education students participated in the study. The examination group consisted of professional athletes performing sport for a period mat less than 5 years. The purpose of examination was to assess the biomechanical properties of the lower limbs (measured during static and dynamie exercises).

9

Komputerowa ocena postawy ciała młodych piłkarzy nożnych wybrane parametry biomechaniczne

Pietraszewska J., Pietraszewski B., Burdukiewicz A.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2009

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Vol. 15, nr 4

352-355

PL

Wstęp. Postawa ciała uwarunkowana jest napięciem odpowiednich grup mięśni, które decydują o określonym ułożeniu poszczególnych segmentów ciała człowieka. Coraz częściej wśród dzieci i młodzieży pojawiają się różnego rodzaju wady postawy ciała, które mogą być spowodowane czynnikami funkcjonalnymi. Jedną z przyczyn ich powstawania może być asymetria obciążeń, jaka często występuje w treningu specjalistycznym. Materiał i metody. Materiał badawczy stanowią wyniki pomiarów 24 piłkarzy nożnych w wieku 15 lat. Badania obejmowały ocenę postawy ciała, cechy antropometryczne oraz pomiary momentów sił prostowników i zginaczy stawu kolanowego. Pomiar statycznego momentu siły mięśniowej przeprowadzono na specjalnym stanowisku pomiarowym firmy OPIW. Do oceny postawy ciała wykorzystano sprzężony z komputerem posturometr S. Wyniki i wnioski. Kryterium oceny pomiaru kręgosłupa w płaszczyźnie czołowej była wartość kąta Cobba. Na tej podstawie stwierdzono występowanie skoliozy lub śladowej skoliozy lewostronnej u 29,3% badanych piłkarzy. W grupie ogółu badanych stwierdzono nieznaczną dominację prostowników i zgi- naczy prawej kończyny dolnej nad lewą. Ta sama tendencja występuje u osób bez skoliozy. U zawodników z bocznym skrzywieniem kręgosłupa dominują mięśnie prostujące i zginające staw kolanowy kończyny lewej. Ważnym kryterium oceny dozowanych obciążeń treningowych piłkarzy nożnych w obrębie prawej i lewej strony ciała może być badanie postawy ciała i momentów sił obydwu kończyn dolnych. Pozwoli to na ewentualne zniwelowanie nieprawidłowości w stosowanych metodach treningowych, które mogą być przyczyną problemów zdrowotnych sportowców.

EN

Introduction. Body posture is determined by muscular tone of the particular muscles that decide about the specific position of the human body segments. This feature is influenced by a tension of muscle groups, which determine the position of separate human body segments. Varius types of spinal abnormalities are caused by functional factors. Material and method. 24 soccer players in the age of 15 were examined. The study included body posture, anthropometric features, the force moments of knee joint flexors and extensors. The static measurements of the muscles’ force moment were evaluated on the special measurement post, made by OPIW Company. The body posture was assessed by means of computer aided posturometer S. Results and conclusions. The value of Cobb angle was the evaluation criterion for the spine measurement in the frontal plane. On that basis the scoliosis or the weak symptoms of left side scoliosis in 29,3% examined players were registered. A slight domination of the right lower limb extensors and flexors over left limb was observed in the research group. The same tendency is observed in the group without scoliosis. The opposite strength arrangement i.e. the domination of flexors and extensors bending left limb knee joint, was found in players with scoliosis. The examination of body posture and force moments of two limbs can be an important evaluation criterion of dosed training loads in soccer players within the area of both left and right body sections. It will help avoiding incorrectness in the applied methods, which may cause athletes’ health problems.

10

Predictive torque equations for joints of the extremities

Bober T., Kulig K., Burnfield J. M., Pietraszewski B.

Acta of Bioengineering and Biomechanics

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2002

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Vol. 4, nr 2

49-60

EN

The purpose of this study was to develop regression equations predicting torque output throughout the range of motion for the human elbow, shoulder, knee, and hip. Twenty-two healthy males participated. Torque values throughout the sagittal plane range of motion (i.e., flexion and extension) of the right elbow, shoulder, knee and hip were recorded (isokinetic dynamometer, 1 rad/sec) and expressed as a percentage of the peak torque produced for each motion. For each joint tested, regression equations based on ensemble-averaged, normalized torque data were calculated to predict the relative torque throughout the investigated range of motion when torque in one angular position was known. Shoulder flexion was best described by a second-order polynomial, while shoulder extension, elbow and knee flexion and extension, and hip flexion were described best by third-order polynomials. Hip extension was best described by a fourth-order polynomial. The regression multiple R2 values ranged between 0.998 and 1.000. These regression equations can be used to predict the expected torque anywhere in the sagittal plane range of motion based on knowledge of a torque recorded at another joint angle for the elbow, shoulder, knee, or hip joint. These equations can be used in the clinical setting when a direct examination of strength capability is not possible due to limitations in equipment or due to the presence of pain within the arc of motion.