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KINEMATIC PARAMETERS OF HURDLE CLEARANCE MOTION IN YOUNG, NOVICE ATHLETES
Get PDFThe purpose of the present study was to assess hurdle kinematics of young athletes when clearing the first two hurdles (0.76 m height) of a simulated hurdle race. Participants run the distance from the starting line to the 2nd hurdle. All trials were video recorded in order to evaluate specific kinematic variables related to hurdle clearance motion. Results revealed that young athletes negotiate the hurdles with lower values of horizontal velocity and hurdle clearance distance parameters, and tend to adopt “a jumping action” over the hurdle compared to the motor pattern of more skilled hurdlers. Horizontal velocity variation affected the technical model of hurdle clearance at the 2nd hurdle, compared to the 1st hurdle, forcing young participants to clear the 2nd hurdle with higher vertical displacement
ELECTROMYOGRAPHY ANALYSIS OF FOREARM MUSCLES DURING VARIOUS YOGA POSES
Get PDFThe current study examined muscle activity via electromyography of the flexor carpi radialis (FCR), ulnaris (FCU), and extensor carpi radialis (ECR), ulnaris (ECU) during two variations of three separate yoga poses. Nine participants (n=9) performed three different yoga poses: plank, side-plank, and upward dog; in two separate variations, (V1) with the wrists in a passive hyperextended position, and (V2) with the wrists in a neutral position where the participants made a fist and performed the pose in that position. There were no differences between poses or variations for ECR. A difference was found between variations, but not poses for ECU. FCR and FCU were different between poses, but not variations. The only interaction was for the FCR. Due to the increased muscle activity in V2, performing yoga in V1 position may allow a yoga session to be completed with less fatigue and risk for injury
FORCE ASYMMETRY DURING ISOMETRIC CONTRACTIONS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION
Get PDFThe aim of this study was to compare isometric strength asymmetry in participants that have previously undergone anterior cruciate ligament (ACL) reconstruction and a healthy control group. Three-dimensional force data (1000 Hz) were collected from 21 ACL (3.2 ± 1.8 years post-surgery) and 21 control participants during maximal isometric contractions. Peak knee flexion force displayed significant asymmetry differences between groups, with ACL participants showing greater asymmetry (7.6 %) than the control group (0.1 %). No significant asymmetry differences were found between groups for peak extension, adduction and internal rotation force. Results suggest that following ACL reconstruction and rehabilitation, external force production during knee flexion is significantly less on the affected side than the uninjured side, which has implications on rehabilitation monitoring
EFFECT OF THE NORDIC HAMSTRING EXERCISE ABILITY ON IN-VIVO FASCICLE DYNAMICS DURING VARIATIONS OF THE NORDIC HAMSTRING EXERCISE.
Get PDFThe purpose of this study was to determine if the ability to perform the Nordic hamstring exercise (NHE) impacts upon the fascicle dynamics of the bicep femoris long head during the NHE performed flat, declined and inclined. 10 physically active individuals (8 males and 2 females, age 24.1±3.9 years, body mass 81.8±8.9kg, height 178.8±7.7cm) with a history of performing the NHE, were separated into two equal groups of high and low performers of the NHE via break point angle assessed using 3D motion capture. Dynamic ultrasound (US) videos were collected using a 10cm probe, while semi-automatic software analysed the dynamic US videos. Fascicle lengthening during the NHE is dependent on NHE performance ability, with likely differences (non- overlapping control limits) between high and low performers. While absolute fascicle change was greater in the incline NHE for low performers, greater FL change was observed in the flat NHE for high performers. This could be as a result of the high performers possessing greater resting fascicle length and eccentric hamstring strength
THE EFFECT OF NEUROMUSCULAR TRAINING WITH APOSTHERAPY SYSTEM IN RECREATIONAL FEMALE ATHLETES WITH A HIGH RISK FOR A NON-CONTACT ANTERIOR CRUCIATE LIGAMENT INJURY
Get PDFInjury to the anterior cruciate ligament (ACL) is considered one of the most debilitating knee injuries which could occur in any young athlete. ACL injuries have short and long-term morbidity consequences, with all the negative impact in the individual wellbeing and health-system. Mitigation of the risk factors (e.g., knee valgus) through training are key in reducing the risk of an ACL injury. However, the majority of neuromuscular training programs require a time-intensive commitment and have a considerable level of complexity and intensity, thus reducing compliance to the programs AposTherapy is a foot-worn biomechanical device which aims to alter alignment and enhance neuromuscular control but has the advantage as a simpler intervention. .. The purpose of this study was to investigate the effect of implementing an unstable footwear device, AposTherapy system, on lower limb biomechanics in recreational female athletes The study identified a significant reduction in knee valgus angle in the AposTherapy group. Utilising foot-worn biomechanical interventions may be a different method for mitigating risks of ACL injury
USING SHIN LENGTH TO DETERMINE KICK PLATE POSITION OPTIMIZES SELECT SWIM START MECHANICS IN ELITE SWIMMERS
Get PDFThe track start kick plate position is often decided by the level of comfort of the swimmer. The purpose of this study was to use shin length as a measure to determine kick plate position and effects on performance. 20 elite swimmers performed 3 starts at 3 kick plate distances (\u3c shin length, shin length, and \u3e shin length). Differences in reaction time, block phase time (BT), flight phase time, flight distance, underwater phase time, time to the 15 m mark, knee flexion and ankle dorsiflexion angles were examined between the positions. BT was significantly different, (F(2,38)=4.264, p=.026). BT was lower when the kick plate distance was one shin’s length versus \u3c shin length (0.691+0.055 vs 0.715+0.056 sec) and \u3e shin length (0.691+0.055 vs 0.698+0.056 sec), p\u3c.05. Shin length is a quick and individualized measure that can be used by coaches to set the kick plate position without compromising performance
A COMPARISON OF HAMSTRING MUSCULOTENDON DYNAMICS DURING HIGH-SPEED RUNNING BEFORE AND AFTER A FATIGUE EXERCISE
Get PDFThe purpose of this study was to compare the musculotendon dynamics of individual hamstring muscles between before and after a soccer-specific fatigue exercise during the late swing phase of high-speed running. Eight male soccer players performed three sprintings before and after the fatigue exercise. Whole-body kinematic data and ground reaction forces of the support leg were recorded using a three-dimensional motion analysis system and force platform. A three-dimensional musculoskeletal model with 43 Hill-type musculotendon models was used to estimate the musculotendon dynamics. The results of this study showed that there were no significant differences in the peak values of musculotendon force, power, length, and elongation velocity in the hamstring muscles before and after the fatigue exercise
FALLING AS A STRATEGY TO DECREASE KNEE LOADING DURING LANDINGS
Get PDFAnterior cruciate ligament injuries often occur when individuals land with a single leg. Falling has been suggested as a potential strategy to decrease knee loading during landings. The purpose was to compare knee flexion angles, peak impact forces, and peak knee extension moments among natural landings, soft landings, and falling in forward and vertical landing tasks under single or double leg conditions. Sixteen male and sixteen female participants completed each landing condition, while three-dimensional kinematics and ground reaction forces (GRF) were collected. In the natural landing condition, participants landed as they would in a sport setting. In the soft-landing condition, participants landed as softly as possible with increased knee and hip flexion. In the falling condition, participants initially landed softly and then fell forward or backward onto a mat in the forward and vertical landing tasks, respectively. Knee flexion angles at initial contact and peak knee flexion angles were generally the greatest for the falling, the second greatest for the soft landing, and the least for the natural landing. Peak vertical and posterior GRF and knee extension moments during early landing were generally the least for the falling, the second least for the soft landing, and the greatest for the natural landing. When the sports environment allows, falling appears to be an innovative strategy to decrease knee loading when individuals must land with a single leg and sub-optimal body postures
FORCE-SHARING BETWEEN TRICEPS SURAE MUSCLES DURING REHABILITATION EXERCISES FOR ACHILLES TENDINOPATHY
Get PDFThe purpose of this study was to determine individual muscle forces of the Triceps Surae during a range of rehabilitation exercises for Achilles tendinopathy. We used experimental data (N=4) and musculoskeletal modelling to estimate muscle force (dynamic optimization). We observed clear peak muscle force differences between exercises. In addition, the force-sharing strategies used by the participants (i.e., individual muscle contribution to the total force produced within the Triceps Surae) were different between exercises. These preliminary results could be helpful to objectively determine the progression in exercise loading throughout rehabilitation programs. Additionally, new information regarding the influence of the type of exercise on load distribution within the Triceps Surae may better orientate practitioners in the choice of exercise
AN AGE-BASED KINETIC ANALYSIS THAT UNDERPINS JOINT COORDINATION IN RUNNING PERFORMANCE
Get PDFThe purpose of this study was to examine the age-based biomechanics that underpins lower body joint coordination during running gait. A longitudinal approach was adopted and experienced male distance runners (initially with a mean age = 53.34 years) were examined over a seven-year period. Three-dimensional joint coordinate and contact ground reaction force data were collected for running trials with a horizontal velocity = 3.83±0.40 m·s-1. ANOVA showed significant increases (p \u3c 0.03) in knee joint moments at amortisation and peak impact and braking forces. Statistical parametric mapping identified decreased hip moments at ~25-40 % of stance. With age there is an increase requirement to attenuate the passive impact forces which places the lower body musculature under further stress. The changes in hip moments, whilst the hip joint is extending, suggests a shift in power production to the knee and ankle which has been previously reported with faster running (Ferris et al., 2012)