The Effect of Fatigue on the Time to Stability in Jumping and Landing in Football Players Who Have Undergone Anterior Cruciate Ligament Reconstruction

Background: Jumping and landing are common activities in soccer that are often reported in connection with anterior cruciate ligament injury. As most injuries occur during fatigue, the present study aimed to investigate the effect of fatigue on the component of time to stability (TTS) during landing between healthy soccer players and soccer players who have undergone anterior cruciate ligament reconstruction.Methods: This quasi-experimental study included 24 professional soccer players who were divided into control and experimental groups. Twelve active professional soccer players (control group) and 12 soccer players with 6-24 months of anterior cruciate ligament reconstruction with hamstring graft (experimental group) participated in this study. Athletes jumped and landed on the obstacle to a height of 7.5 cm. After the fatigue protocol, these movements were repeated. TTS data was collected using force plate. MANOVA test at the significant level of p <0.05 was used to compare pre-test and post-test data between the groups.Results: According to the results of this study, fatigue did not affect the time to stability in any of the anterior-posterior (p=0.104), internal-external (p=0.668), or vertical components (p=0.894) between the two groups, and fatigue could not make a significant difference between the two groups. Moreover, before fatigue, no significant difference was observed between the two groups in any of the components.Conclusion: It seems that a plyometric fatigue training session will not be effective in differentiating between healthy soccer players and soccer players who have had anterior cruciate ligament reconstruction

The effect of backpack load on the posture of children and its relationship to trunk muscle activity during walking on a treadmill

The investigation began during the spring of 2009. The subjects volunteered to participate from all across the state of Saarland through the Saarbrücker Zeitung. Of the total 76 subjects, 41 (23 girls and 18 boys) attended kindergarten while 35 (12 girls and 23 boys) attended the first grade in elementary school. Two subjects were tested every day over the course of nine weeks, starting April 11th 2009. Their weight is then measured and immediately 10, 20 and 30 % of their body weight is calculated to be used later during the treadmill walk.The investigation was made up of three parts: a questionnaire, EMG and video analysis of kinematic body posture. With the increase of the backpack weight, the trunk inclination angle progressively increased and trunk motion range decreased linearly.With the increase of the backpack weight, the distance from the floor to the earlobe joint (height) decreased.With the weight of backpack at about 10 % and 20 % body weight (BW) step length increased and at 30 % BW decreased. There was an increase of muscle activity in the upper trapezius at 20 % and 30 % BW as well as median power frequency at 30 % BW.This shows that there was no muscle fatigue in the upper body.With the increase of the backpack weight, the muscle activity of the thoracic erector spine at T12 and lumbar erector spinae at L3 decreased and median power frequency existed for all load conditions.There was muscle fatigue found in all load conditions in the thoracic erector spine at T12 and lumbar erector spinae at L3. The mean weight of the backpack carried by children was 4.1 kg, which is around 16.7 % of their body weight.27.63 % of the children walked less than 1 km from their house door to kindergarten/school, 28.95 % walked approximately 1 km, and 43.42 % walked more than 1 km.Die Untersuchung begann im Frühjahr 2009. Die Probanden, aus dem gesamten Saarland stammend, beteiligten sich freiwillig nach einem Aufruf in der Saarbrücker Zeitung. Von den insgesamt 76 Probanden gingen 41 (23 Mädchen und 18 Jungen) in den Kindergarten, während 35 (12 Mädchen und 23 Jungen) die erste Klasse in der Grundschule besuchten.Die zusätzlichen Lasten des Schulranzen betrugen 0 %, 10 %, 20 % und 30 % des Körpergewicht des Kindes. Jede Belastungsstufe wurde für 5 Minuten durchgeführt. Die ersten und letzten 10 Sekunden eines jeden Belastungszustandes wurden per Video sowie EMG-Signale aufgezeichnet.Die Untersuchung bestand aus drei Teilen: einem Fragebogen, einer EMG-Analyse und einer Video-Analyse der kinematischen Körperhaltung. Mit der Zunahme des Schulranzengewichts nimmt der Rumpfwinkel schrittweise zu, das Bewegungsausmaß nimmt hingegen linear ab.Mit der Zunahme des Schulranzengewicht nahm die Körperhöhe (Abstand vom Boden zu den Ohrläppchen) ab.Bei der Gewichtszunahme des Schulranzen auf 10 % und 20 % des Körpergewichts hat die Schrittlänge zugenommen, bei einer Belastung mit 30 % des Körperge-wichts hat sie hingegen abgenommen. Es gab eine Zunahme der Muskelaktivität beim oberen Trapezius bei 20 % und 30 % Belastung sowie der median power frequency bei 30 % Belastung.Dies zeigt, dass es keine Muskelermüdung im Upper trapezius gibt.Mit der Zunahme des Schulranzengewichts nahm die Medianfrequenz (MPF) des Thoracic erector spinae bei T12 und der Erector spinae lumbar bei L3 ab.Es wurde eine Muskelermüdung in allen Belastungsstufen im thoracic erector spine bei T12 und im lumbar erector spinae bei L3 festgestellt. Das Mittelwert Schulranzengewicht der Kindern betrug 4,1 kg, was durchschnittlich 16,7 % ihres Körpergewichts entsprech. 27,6 % der Kinder hatten einen Weg von der Haustür bis zur Schule/zum Kindergarten, der weniger als 1 km betrug, bei 28,9 % betrug er ungefähr 1 km und bei 43,4 % war er länger als 1 km

Der Einfluss der Belastung von Schulranzen auf die Körperhaltung von Kindern am Beispiel der Rumpfmuskelaktivität beim Laufen auf einem Laufband

The investigation began during the spring of 2009. The subjects volunteered to participate from all across the state of Saarland through the Saarbrücker Zeitung. Of the total 76 subjects, 41 (23 girls and 18 boys) attended kindergarten while 35 (12 girls and 23 boys) attended the first grade in elementary school. Two subjects were tested every day over the course of nine weeks, starting April 11th 2009. Their weight is then measured and immediately 10, 20 and 30 % of their body weight is calculated to be used later during the treadmill walk.The investigation was made up of three parts: a questionnaire, EMG and video analysis of kinematic body posture. With the increase of the backpack weight, the trunk inclination angle progressively increased and trunk motion range decreased linearly.With the increase of the backpack weight, the distance from the floor to the earlobe joint (height) decreased.With the weight of backpack at about 10 % and 20 % body weight (BW) step length increased and at 30 % BW decreased. There was an increase of muscle activity in the upper trapezius at 20 % and 30 % BW as well as median power frequency at 30 % BW.This shows that there was no muscle fatigue in the upper body.With the increase of the backpack weight, the muscle activity of the thoracic erector spine at T12 and lumbar erector spinae at L3 decreased and median power frequency existed for all load conditions.There was muscle fatigue found in all load conditions in the thoracic erector spine at T12 and lumbar erector spinae at L3. The mean weight of the backpack carried by children was 4.1 kg, which is around 16.7 % of their body weight.27.63 % of the children walked less than 1 km from their house door to kindergarten/school, 28.95 % walked approximately 1 km, and 43.42 % walked more than 1 km.Die Untersuchung begann im Frühjahr 2009. Die Probanden, aus dem gesamten Saarland stammend, beteiligten sich freiwillig nach einem Aufruf in der Saarbrücker Zeitung. Von den insgesamt 76 Probanden gingen 41 (23 Mädchen und 18 Jungen) in den Kindergarten, während 35 (12 Mädchen und 23 Jungen) die erste Klasse in der Grundschule besuchten.Die zusätzlichen Lasten des Schulranzen betrugen 0 %, 10 %, 20 % und 30 % des Körpergewicht des Kindes. Jede Belastungsstufe wurde für 5 Minuten durchgeführt. Die ersten und letzten 10 Sekunden eines jeden Belastungszustandes wurden per Video sowie EMG-Signale aufgezeichnet.Die Untersuchung bestand aus drei Teilen: einem Fragebogen, einer EMG-Analyse und einer Video-Analyse der kinematischen Körperhaltung. Mit der Zunahme des Schulranzengewichts nimmt der Rumpfwinkel schrittweise zu, das Bewegungsausmaß nimmt hingegen linear ab.Mit der Zunahme des Schulranzengewicht nahm die Körperhöhe (Abstand vom Boden zu den Ohrläppchen) ab.Bei der Gewichtszunahme des Schulranzen auf 10 % und 20 % des Körpergewichts hat die Schrittlänge zugenommen, bei einer Belastung mit 30 % des Körperge-wichts hat sie hingegen abgenommen. Es gab eine Zunahme der Muskelaktivität beim oberen Trapezius bei 20 % und 30 % Belastung sowie der median power frequency bei 30 % Belastung.Dies zeigt, dass es keine Muskelermüdung im Upper trapezius gibt.Mit der Zunahme des Schulranzengewichts nahm die Medianfrequenz (MPF) des Thoracic erector spinae bei T12 und der Erector spinae lumbar bei L3 ab.Es wurde eine Muskelermüdung in allen Belastungsstufen im thoracic erector spine bei T12 und im lumbar erector spinae bei L3 festgestellt. Das Mittelwert Schulranzengewicht der Kindern betrug 4,1 kg, was durchschnittlich 16,7 % ihres Körpergewichts entsprech. 27,6 % der Kinder hatten einen Weg von der Haustür bis zur Schule/zum Kindergarten, der weniger als 1 km betrug, bei 28,9 % betrug er ungefähr 1 km und bei 43,4 % war er länger als 1 km

Effect of Hip Abductor Muscle Fatigue on Static and Dynamic Balance in Elderly Women

Objectives: Postural control is the act of maintaining and restoring a better state of balance and proper biomechanics structure in limbs and different parts of the body. Such proper structure exists in two forms namely static and dynamic. Fatigue is one of the factors that affect the postural control and body stability. The purpose of this study was to examine the effect of hip abductor muscle fatigue on the static and dynamic balance in elderly women. Methods & Materials: The participants of this study included 25 elderly and healthy women without any disability (60.24&plusmn;8.5 years old, weight: 60.58&plusmn;9.54 kg, height: 153.42&plusmn;7.65 cm). In the first session, the participants underwent static and dynamic balance tests in the normal condition (without fatigue). In the second session, at first, they participated in the hip abductor muscle fatigue protocol followed by static and dynamic balance tests. In addition, t-test was used to compare the results before and after the fatigue. Results: The results indicated that the hip abductor muscle fatigue protocol led to a significant reduction in test scores of balance tests, which included static and dynamic balance. Also, a significant difference was observed between static and dynamic balance before and after fatigue. Overall, the measure of the effect of fatigue protocol was notable in both the tests (P<0.05). Conclusion:&nbsp;Reduction in the scores of static and dynamic balance tests showed that the hip abductor muscle fatigue caused an increase in the amount of damage and length of disability in elderly women

Evaluation of surface electromyography of selected neck muscles during the whiplash mechanism in aware and unaware conditions due to safe punching in kickboxing

Abstract Background Kickboxing is considered as a combat sport in progress, in which injuries are frequent and significant, and close injury monitoring is highly recommended. Sports injuries to the head and neck are estimated to cause 70% deaths and 20% permanent disabilities although they are much less common than those to the limbs. Whiplash mechanism involves the rapid extension (opening) and flexion (bending) of neck. The purpose of the current study was to investigate the electromyographic activity of selected muscles in the whiplash mechanism in aware and unaware conditions of the safe punching in kickboxing so that we can design special exercises. Method In the present study, 24 male kickboxing athletes aged 18–40 years were selected based on a purposive sampling method. The surface electromyography (EMG) signals of muscles were recorded with and without awareness of safe punching by using a nine-channel wireless EMG device. Additionally, a nine-channel 3D inertial measurement unit (IMU, wireless,) was utilized to determine the acceleration, kinematics, and angular velocity of the subjects’ head. The statistical dependent t-test was applied to compare the EMG activity of each muscle, as well as its participation ratio. Results The results of statistical analysis represented a significant increase in the EMG activity of sternocleidomastoid (p = 0.001), upper trapezius (p = 0.001) and cervical erector spinae muscles (p = 0.001), as well as the neck extension and flexion angles between the athletes aware (open eyes) and unaware (closed eyes) of the safe punching. Conclusion In this study, the EMG activity of the sternocleidomastoid, upper trapezius, and cervical erector spine muscles in the aware condition was significantly different from the activity under unaware condition. In fact, the intended muscles exhibited significantly different behaviors in preventing extension and flexion in the two conditions

Comparison of Static and Dynamic Balance of Physically Active College Women with Different Foot Arch Heights

Introduction: Balance is one of the pivotal and inseparable components in daily activities and sports performance. Better and more comprehensive recognize of effective factors on quality of balance and how they impress, provide the opportunity which helps to improve motor-base factors in whole life and avoids negative impacts. It seems that anatomical abnormalities such as flat and pescavus foot and morphologic features of the foot can affect motor fitness characteristics like balance. So, this research aimed to compare the static and dynamic balance of women college athletes which have different foot arch heights. Materials and Methods: Static and dynamic balance were assessed in 90 women athletes in three types of foot arch: flat foot (30 persons), pescavus foot (30 persons) and normal foot (30 persons); it was done using stabilometer device with open-eye participant and maintaining a single leg stance (a measure of static balance), while dynamic balance was tested with putting a dominant step on a device (a measure of dynamic balance). Besides, to differentiate between flat, pescavus and normal foot arch, the navicular drop was tested with Brady attributive method. To test and analyze statistical datum, also one-way ANOVA statistical method was used via SPSS19 software. Results: There was a significant difference in total area of the swing movement (P = 0.002) in static balance; however, there is not any significant difference between the study groups in dynamic balance (P = 0.098). Conclusion: Although static balance in person who suffers from flat and pescavus foot arch abnormality is lower than normal foot arch, but in dynamic balance, no significant differences between the three groups of foot arch height were noticed. So, the people who suffers from flat and pescavus foot arch should do their daily activities with more accuracy and attention

The Effect Rehabilitation Exercise on the Upper Crossed Syndrome in Patients with Coronary Artery Bypass Surgery

Introduction: Due to the importance of correct posture and the association of inappropriate posture with pain in the chest and scapula, the aim of this was to investigate the impact of rehabilitation exercise on the upper crossed syndrome in coronary artery bypass surgery patients.   Materials & Methods: The statistical population consisted of all the 44 to 70-year-old men with coronary artery bypass surgery and upper crossed syndrome referred to Valiasr Hospital of Qom. The participants included 30 subjects (experimental group 10, control group 10 and test group10) who were randomly selected to participate in the study. In the test group a day before surgery and 8 weeks after surgery and in the control and experimental groups, 8 weeks after surgery and 8 weeks after the first test, the associated tests were run. To analyze the data, t-test Wilcoxon, and analysis of covariance were used. Findings: According to the results of the experimental group, the exercises had a significant positive (p<0.05) effect on kyphosis and forward head postures and had a positive, but not significant, effect on rounded shoulders. In the test group, the trainings had a significant positive effect on kyphosis, forward head, and rounded shoulder on the left side (p<0.05), while it had a positive, but non-significant, effect on rounded shoulder on the right side.   Discussion & Conclusions: In the present study, combination trainings using isometric, tread band, and stretching movements were effective in correcting forward head, kyphosis, and rounded shoulder postures in patients undergoing coronary artery bypass surgery

The effects of the Posterior X Taping versus augmented feedback on lower‐extremity kinematic and muscle activity pattern during unilateral weight‐bearing activities in men with tibiofemoral varus malalignment

Abstract Purpose Tibiofemoral Varus Malalignment (TFRV) contributes to overuse injuries by altering lower limb biomechanics. Both Posterior X Taping (PXT) and Real Time Feedback (RTF), have each been recommended for subjects with TFRV as they are thought to enhance control of excessive tibiofemoral rotations. This paper evaluates this claim. Methods A total of recreational male 24 athletes with TFRV participated in the current study. Kinematic and electromyography variables of lower extremity were synchronously ​recorded on five consecutive repetitions of the single‐legged‐squat (SLS) and forward‐step‐down) FSD) tasks before and after applications of PXT and RTF. Results The subjects at post‐intervention in RTF group exhibited decreased hip adduction during FSD, and decreased hip adduction and internal rotation during eccentric and concentric phases of the SLS; Additionally, we observed increased gluteus medius activity during eccentric phase of the SLS and FSD tasks. In contrast, subjects at the post‐intervention in PXT group exhibited decreased tibiofemoral external rotation and increased ankle external rotation during all the phases of both SLS and FSD tasks. Conclusion These results suggest that the PXT and RTF interventions are recommended to immediately improve the functional defects of the subjects with TFRV during SLS and FSD tasks