Wyniki wyszukiwania - Biblioteka Nauki

1

Acute Effects of Whole Body Vibration on Shoulder Muscular Strength and Joint Position Sense

100%

Hong J. , Velez M. , Moland A. , Sullivan J.

Journal of Human Kinetics

|

2010

|

tom 25

17-25

EN

Functional changes following whole body vibration (WBV) training have been attributed to adaptations in the neuromuscular system. However, these changes have mainly been observed in the lower extremity with minimal change to the upper extremity. The purpose of the study is to examine the acute effect of shoulder vibration on joint position sense and selected muscle performance characteristics (peak torque, time to peak torque, and power). Forty young individuals (19.84 ± 1.73 yrs, 171.41 ± 7.73 cm, 70.07 ± 9.32 kg) with no history of upper body injuries were randomly assigned to an experimental (Vibration) or control (No-Vibration) group. To assess shoulder proprioception, active and passive joint position senses were measured on both internal and external rotation of the shoulder. The muscle performance variables (peak torque and time to peak torque) were measured using isokinetic dynamometer with the velocity of 60°/sec. After three bouts of 1 minute vibration training, the experimental group demonstrated a significant improvement in the internal rotation peak torque, time to peak torque and external rotation time to peak torque (p<0.05). However, no-significant differences were revealed for joint position sense, external rotation peak torque, and time to peak torque between the groups. Our findings suggest that short bouts of vibration treatment have a significant effect on shoulder muscle characteristics.

2

Effect of a Short Time Concentric Versus Eccentric Training Program on Electromyography Activity and Peak Torque of Quadriceps

88%

Carvalho A. , Caserotti P. , Carvalho C. , Abade E. , Sampaio J.

Journal of Human Kinetics

|

2014

|

tom 41

|

nr 1

5-13

EN

The purpose of this study was to examine the effect of an 8-week concentric (CON) versus eccentric (ECC) isokinetic training program on the electromyography (EMG) signal amplitude of vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF). Also, the isometric (ISO) and dynamic maximum strength of the knee extensors were assessed. Eighteen physically healthy male subjects (age 22 ± 1 years, body height 177 ± 4 cm, body mass 73 ± 7 kg) performed four weeks of unilateral CON isokinetic training for the quadriceps of the dominant leg on a REV9000 dynamometer. At the end of the fourth week, the sample was divided into two groups, with one group performing additional four weeks of unilateral ECC training and the other continuing with CON training. The training sessions consisted of three sets of ten maximal repetitions at a velocity of 60°s-1, three days per week for eight weeks. The results showed that CON and ECC groups improved the peak torque in all types of contractions. Also, both groups presented increases in the avgEMG for VL, VM and RF. The present investigation showed that CON training elicited increases of the ISO peak torque and VM avgEMG in the CON contraction. Additionally, significant gains were reported after the ECC training on the VM avgEMG in all contractions and RM avgEMG in CON contraction.

3

Isokinetic Leg Strength and Power in Elite Handball Players

88%

González-Ravé J. M. , Juárez D. , Rubio-Arias J. A. , Clemente-Suarez V. J. , Martinez-Valencia M. A. , Abian-Vicen J.

Journal of Human Kinetics

|

2014

|

tom 41

|

nr 1

227-233

EN

Isokinetic strength evaluation of the knee flexion and extension in concentric mode of contraction is an important part of the comprehensive evaluation of athletes. The aims of this study were to evaluate the isokinetic knee peak torque in both the extension and flexion movement in the dominant and non-dominant leg, and the relationship with jumping performance. Twelve elite male handball players from the top Spanish handball division voluntary participated in the study (age 27.68 ± 4.12 years; body mass 92.89 ± 12.34 kg; body height 1.90 ± 0.05 m). The knee extensor and flexor muscle peak torque of each leg were concentrically measured at 60°/s and 180°/s with an isokinetic dynamometer. The Squat Jump and Countermovement Jump were performed on a force platform to determine power and vertical jump height. Non-significant differences were observed between legs in the isokinetic knee extension (dominant= 2.91 ± 0.53 Nm/kg vs non-dominant = 2.70 ± 0.47 Nm/kg at 60°/s; dominant = 1.90 ± 0.31 Nm/kg vs non-dominant = 1.83 ± 0.29 Nm/kg at 180°/s) and flexion peak torques (dominant = 1.76 ± 0.29 Nm/kg vs non-dominant = 1.72 ± 0.39 Nm/kg at 60°/s; dominant = 1.30 ± 0.23 Nm/kg vs non-dominant = 1.27 ± 0.35 Nm/kg at 180°/s). Low and non-significant correlation coefficients were found between the isokinetic peak torques and vertical jumping performance (SJ = 31.21 ± 4.32 cm; CMJ = 35.89 ± 4.20 cm). Similar isokinetic strength was observed between the legs; therefore, no relationship was found between the isokinetic knee flexion and extension peak torques as well as vertical jumping performance in elite handball players.

4

The influence of exercises under isokinetic conditions on heart rate in males aged between 40 and 51

75%

Czamara A. , Krzemińska A. , Szuba Ł.

Acta of Bioengineering and Biomechanics

|

2011

|

tom Vol. 13, no. 3

95-104

EN

The aim of the study was to estimate changes in heart rate (HR) values in response to the exercise under isokinetic conditions, with defined protocol using three different angular velocities and 2 minute break. The subjects were divided into two groups. The first group contained 18 males aged between 40 and 50, and the second group contained 20 males who were 20–30 years old. The heart rate was monitored before, during and after the strength moment measurement under isokinetic conditions of extensors and flexors of knee joint. The strength moment was measured with an angular velocity of 180 °/s, 120°/s and 60 °/s. The number of repetitions of extension and flexion of the knee joint was 10 for the angular velocity of 180 °/s, 8 for the angular velocity of 120 °/s and 5 for the angular velocity of 60 °/s. The break between each series of repetitions took 2 minutes. The peak torques for extensors and flexors of both lower extremities were measured. The peak torque and heart rate values increased with a decrease in the preset angular velocity and were lower in the second group. The results were within the norm accepted for submaximal heart rate index in both age groups.

5

Reliability of Concentric, Eccentric and Isometric Knee Extension and Flexion when using the REV9000 Isokinetic Dynamometer

75%

Pereira de Carvalho Froufe Andrade A. C. , Caserotti P. , Pereira de Carvalho C. M. , André de Azevedo Abade E. , Jaime da Eira Sampaio A.

Journal of Human Kinetics

|

2013

|

tom 37

|

nr 1

47-53

EN

The aim of this study was to assess the reliability of isokinetic and ISO knee extensor and flexor muscle strength when using the REV9000 (Technogym) isokinetic dynamometer. Moreover, the reliability of several strength imbalance indices and bilateral ratios were also examined. Twenty-four physically active healthy subjects (age 23±3 years) underwent three testing sessions, two on the same day and a third, 7 days later. All sessions proceeded in the same order: five concentric contractions at 60ºs-1 followed by an isometric contraction (5 seconds) and five eccentric contractions (60ºs-1). The results of this study showed a high reproducibility in eccentric (0.95-0.97), concentric (0.95- 0.96) and isometric (0.93-0.96), isokinetic strength for knee extensor and flexor muscles, thus indicating that the REV9000 isokinetic dynamometer can be used in future sports performance studies. A low-to-moderate reliability was found in the isokinetic strength bilateral ratios while the Hamstring:Quadricep concentric ratio showed moderate reliability. The highest reliability (>0.90) was observed in the dynamic control ratio (Hamstring eccentric:Quadricep concentric) which consequently confirms that it is a more valid indicator for imbalanced reciprocal parameters and can be used in rehabilitation and sports medicine.

6

Force-Velocity Parameters of Knee Flexors and Extensors in 10-12-Year-Old Children with Spinal and Knee Diseases

75%

Stefańska M. , Zawadzka D.

Human Movement

|

2009

|

tom 10

|

nr 2

144-148

EN

Purpose. Assessment of the muscles force of knee flexors and extensors in children with a scoliosis of the first degree and knock-knees and comparison with healthy children. Basic procedures. Forty-nine boys and girls aged 10-12 years participated in this research project. The subjects were divided into three research groups. Group I included children with first degree scoliosis; Group II children with knock-knees; and Group III healthy children. An analysis of force-velocity parameters of knee flexors and extensors in isokinetic conditions (with the loads of 1.05 rad/s (60°/s), 3.14 rad/s (180°/s) and 4.19 rad/s (240°/s)) was carried out. Each subject had to perform flexion and extension movements of the knee five times, developing peak torque in the shortest time possible in each movement. Main findings. The research showed that healthy children obtained significantly higher values of peak torque, total work and mean power as compared with the other children. However, no significant differences between values obtained by scoliotic children and children with knock-knees were found. Conclusions. Corrective exercise programs for children with scoliosis and children with knock-knees should be accompanied by general fitness exercises directed at improvement of force and endurance of lower limb muscles.

7

Leg strength and power in Polish striker soccer players

63%

Buśko K. , Górski M. , Nikolaidis P. T. , Mazur-Różycka J. , Łach P. , Staniak Z. , Gajewski J.

Acta of Bioengineering and Biomechanics

|

2018

|

tom Vol. 20, no. 2

109--116

EN

The main goal of the present study was to examine muscle strength and power of dominant and non-dominant leg, knee extensors and flexors, and their correlations with jumping performances in soccer players. A secondary aim was to evaluate muscle sense. Methods: 31 male professional strikers (age 20.9 ± 2.3 years, body mass 75.1 ± 6.6 kg, body height 179.5 ± 4.7 cm) participated in the study. The power output of lower extremities and the height of rise of the body mass centre during vertical jumps were measured using a force plate. The maximum muscle torque of the flexors and extensors of the knee were measured under isometric conditions using a special isometric torquemeter. Force sense was measured in isometric conditions in two tests: (a) fifty percent of the maximal voluntary contraction was set as a value of target force and the participants were instructed to reproduce the target force, (b) the participants attempted to develop a torque reproducing a sine course within the range of 10 to 50% of MVC performed. Results: A direct relationship was observed between the peak muscle torque in knee extensors developed during isokinetic contraction at all velocities and power and height of three types of vertical jumps ( p < 0.05). No correlation was observed between jumping performance and muscle torque under isometric condition. No differences were found in strength and jumping abilities as well as in force sense between dominant and non-dominant legs. Conclusions: This study offered a comprehensive and complete evaluation of leg muscle strength, sense and power, with the use of using force plate and isokinetic dynamometry.

8

Reliability and validity of a novel Isokinetic Knee Dynamometer System

63%

Riemann B. M. , Watson M. D. , Davies G. J.

Acta of Bioengineering and Biomechanics

|

2021

|

tom Vol. 23, no. 4

107--116

EN

Purpose: The aim of this work was to determine the intersession reliability and validity of a recently developed prototype Isokinetic Knee Dynamometer to assess isokinetic knee extension and flexion peak moments compared to a Biodex System 4 dynamometer. Methods: Thirty--five healthy participants performed two sessions (48-h separation) of bilateral concentric isokinetic knee extension and flexion on both isokinetic devices at 60 °/s (6 repetitions), 180 °/s (10 repetitions) and 240 °/s (15 repetitions). Dynamometer and limb order were randomized among participants while peak moment of each set was used for data analysis. Results: The Isokinetic Knee Dynamometer had excellent relative reliability, comparable to the System 4, and both systems displayed acceptable absolute reliability. Proportional biases were observed favoring the System 4 during knee extension of both limbs at 60 °/s and the dominant limb at 180 °/s, and fixed biases favoring the Isokinetic Knee Dynamometer in seven conditions. Relative agreement between systems was good across all test conditions with the majority demonstrating excellent agreement. Conclusions: These data support the Isokinetic Knee Dynamometer as a reliable and valid knee isokinetic testing system. Due to its reduced system complexity, space requirements, and production cost, the Isokinetic Knee Dynamometer may increase the clinical utilization of isokinetic knee assessments. Finally, these data fill an existing isokinetics literature void with the results supporting similar and acceptable measurement properties jointly for dominant and non-dominant limbs and at the higher testing velocities considered.

9

Czynność mięśni tułowia u dziewcząt z bocznym idiopatycznym skrzywieniem kręgosłupa I

51%

Stefańska M. , Skrzek A. , Anwajler J. , Malicka I. , Zawadzka D. , Dziubek-Rogowska W.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

|

2008

|

tom Vol. 14, nr 2

116-119

PL

Cel pracy: Analiza parametrów siłowo-prędkościowych mięśni tułowia u dziewcząt z bocznym idiopatycznym skrzywieniem kręgosłupa F, usprawnianych dwiema metodami. Pierwszą z nich były zabiegi kinezyterapeutyczne prowadzone na sali gimnastycznej w ośrodku rehabilitacyjnym, drugą — ambulatoryjny proces korekcyjny w postaci ćwiczeń w wodzie na krytej pływalni. Materiał i metoda: W badaniach uczestniczyło 31 dziewcząt w wieku 10-14 lat, z bocznym idiopatycznym skrzywieniem kręgosłupa F. Spośród uczestników badań wyodrębniono dwie grupy badawcze. Pierwszą stanowiły dzieci usprawniane zabiegami kinezyterapeutycznymi podczas pobytu w Specjalistycznym Rehabilitacyjno-Ortopedycznym ZOZ we Wrocławiu przy ul. Poświęckiej, drugą — dzieci uczestniczące w ambulatoryjnym procesie korekcyjnym w postaci ćwiczeń w wodzie, prowadzonych na krytej pływalni AWF we Wrocławiu. U wszystkich uczestników badań dokonano oceny parametrów prędkościowo-siłowych mięśni zginaczy i prostowników kręgosłupa w warunkach izokinetycznych przy prędkości 60% i 1207s. Przy każdym z obciążeń badany wykonywał 5 naprzemiennych ruchów zginania i prostowania kręgosłupa w płaszczyźnie strzałkowej. Przy każdym pomiarze obowiązywał imperatyw wyzwolenia maksymalnej siły w jak najkrótszym czasie. Wyniki: W badaniach wykazano, że wartości szczytowego momentu siły, siły względnej, całkowitej pracy i średniej mocy mięśni zginaczy i prostowników kręgosłupa są w większości wyższe u dziewcząt usprawnianych podczas pobytu w ośrodku rehabilitacyjnym. Natomiast u dzieci uczestniczących w zajęciach na pływalni zaobserwowano korzystniejszy stosunek siły mięśni zginaczy kręgosłupa do prostowników. Wnioski: Wzbogacenie tradycyjnych modeli usprawniania o zajęcia prowadzone w środowisku wodnym spotęguje niewątpliwie efektywność działań korekcyjnych, a także pozwoli na poszerzenie programu usprawniania o zajęcia ogólnorozwojowe, umożliwiające lepszą kontrolę bilansu siły mięśniowej grup przeciwdziałających.

EN

Purpose: The muscular forcevelocity parameters in girls with idiopathic scoliosis F subjected to two methods of rehabilitation were evaluated. The first method — kinesitherapy procedures were carried out in a gym room of rehabilitation centre. The second one — the corrective process was performed in a swimming pool. Basic procedures: 31 girls with idiopathic scoliosis F, aged 10-14, were involved in the research project. The subjects were divided into two groups that performed exercises in a gym room and in a swimming-pool. Assessment of F-v parameters of trunk flexors and extensors in isokinetic conditions (in 607s and 1207s loads) were conducted. Each subject had to perform 5 times flexion and extension movements in the trunk in the sagittal plane. It was necessary for the subject to develop the peak torque within the shortest possible time, for each movement. Main findings: The research showed that children rehabilitated in the gym room achieved the higher values of peak torque, total work and average power in comparison with another group of children. However, better ratio of force flexion and extension muscles was observed in a group of children performing exercises in water. Conclusions: Adjunctive methods of rehabilitation — water exercises, as well as kinesitherapy will surely improve the effectiveness of the corrective processes and allow to broaden the rehabilitation programme by general fitness exercises that lead to better control of antagonist muscles' force ratio.

10

Isokinetic leg strength in adolescent Malaysian recreational taekwondo practitioners

51%

Kim G. D. , Pieter W.

Ido Movement for Culture. Journal of Martial Arts Anthropology

|

2020

|

tom 20

|

nr 1

49-53

EN

Background. Improved leg strength in taekwondo athletes has been suggested as a way to help prevent hamstrings injuries. Problem and Aim. Research on isokinetic leg strength in Malaysian taekwondo [WTF] athletes has been scarce, especially in recreational participants. The aim of this study was to compare isokinetic leg strength in adolescent Malaysian recreational taekwondo participants. Methods. Strength was assessed in 7 females and 8 males on a Biodex System 3 during leg extension and flexion at 120o/sec and 300o/sec. A 3-way (Gender x Movement x Velocity) ANOVA with repeated measurements of the second and third factors was used to determine differences between gender, extension/flexion and angular velocity. A 2-way (Gender x Velocity) ANOVA with repeated measurements of the second factor was employed to determine differences in hamstrings/quadriceps (H/Q) ratios between the genders by angular velocity. Results. Collapsed over angular velocity and movement, the boys recorded a higher peak torque: eta2=0.47, 80% CI: 0.14 – 0.71, d= 1.93, 80% CI: 0.00 – 9.03 albeit unclear. When scaled to height (m2), relative peak torque was still higher for the boys: eta2=0.38, 80% CI: 0.03 – 0.65 albeit unclear but the pairwise comparison was clear: d= 1.50, 80% CI: 0.49 – 0.69. Dimensional scaling did not fully control for the effect of height on isokinetic leg strength in the girls: r=0.17, 80% CI: 0.00 – 0.67. However, it did not in the boys: r=0.72, 80% CI: 0.32 – 0.90. Conclusions. The results seem to partially support the claim that, as far as isokinetic leg strength is concerned, geometric similarity may not apply. Future studies should compare theoretical strength exponents to those empirically derived in a larger sample.

PL

Tło. Zwiększenie siły nóg u zawodników taekwondo zostało zasugerowane jako sposób zapobiegania urazom ścięgien. Problem i cel. Badania nad izokinetyczną siłą nóg malezyjskich sportowców taekwondo [WTF] są rzadkością, zwłaszcza tych ćwiczących rekreacyjnie. Celem pracy było porównanie izokinetycznej siły nóg nastoletnich malezyjskich zawodników rekreacyjnego taekwondo. Metody. Siłę oceniano u 7 kobiet i 8 mężczyzn w systemie Biodex 3 podczas rozciągania i zginania nóg w temp. 120o/s i 300o/sec. W celu określenia różnic ze względu na płeć, rozciągnięcie/zginanie i prędkość kątową wykorzystano 3-trójstronną (płeć x ruch x prędkość) analizę ANOVA z powtarzającymi się pomiarami drugiego i trzeciego czynnika. W celu określenia różnic w stosunkach między płciami za pomocą prędkości kątowej zastosowano dwustronną (Gender x Velocity) analizę ANOVA z powtarzającymi się pomiarami drugiego czynnika. Wyniki. Przy pomiarach prędkości kątowej i ruchu u chłopców odnotowano wyższy szczytowy moment obrotowy: eta2=0,47, 80% CI: 0,14 - 0,71, d=1,93, 80% CI: 0,00 - 9,03 aczkolwiek wyniki były niejasne. W odniesieniu do skali wysokości (m2), względny szczytowy moment obrotowy był jeszcze wyższy dla chłopców: eta2=0,38, 80% CI: 0,03 - 0,65, co nie dawało jasnych wyników, w przeciwieństwie do porównania w parach, które było jasne: d=1,50, 80% CI: 0,49 - 0,69. Skalowanie wymiarowe nie w pełni kontrolowało wpływ wzrostu na wytrzymałość izokinetyczną nóg u dziewcząt: r=0,17, 80% CI: 0,00 – 0,67, u chłopców wynosiło: r = 0,72, 80% CI: 0,32 - 0,90. Wnioski. Wyniki wydają się częściowo potwierdzać twierdzenie, że w odniesieniu do wytrzymałości izokinetycznej nóg podobieństwo geometryczne może nie mieć zastosowania. Przyszłe badania powinny porównywać teoretyczne wykładniki wytrzymałości z wykładnikami uzyskanymi empirycznie u większej grupy badanej.