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TRUNK BIOMECHANICS OF TRANSTIBIAL AMPUTEES IN LEVEL AND SLOPED GAIT USING RIGID, HYDRAULIC AND MICROPROCESSOR CONTROLLED ANKLES
Get PDFCompensational gait mechanisms, as an increased mediolateral trunk lean, are associated with the development of lower back pain, which is common among individuals with transtibial amputation (TTA). Therefore, the aim of this study was to investigate if different prosthetic ankle devices influence mediolateral trunk angles during gait in TTA. Six TTA and six controls walked in the level and on a positive and negative 5° inclined instrumented ramp using a rigid (RIG), a hydraulic (HYD) and a microprocessor (MPC) ankle component (Chas A Blatchford and Sons, Basingstoke, UK). Prosthetic design did not significantly affect the mediolateral trunk lean in any of the three slope conditions. Therefore, the different prosthetic ankle devices seem to play a minor role for mediolateral trunk lean adaptations. Their potential to reduce lower back pain needs further investigation
Does postural stability improve after using a novel biomechanical device in recreational female athletes at a high risk of 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. Mitigation of the risk factors (e.g., Postural Stability) through training are key in reducing the risk of an ACL injury. However, most neuromuscular training programs require a time-intensive commitment and have a considerable level of complexity and intensity, thus reducing compliance to the programmes. AposTherapy is a novel foot-worn biomechanical device which aims to enhance neuromuscular control and postural stability 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 (postural stability) in recreational female athletes. Individuals wore the device for a period of six weeks and were assessed following this period. The study identified a significant improvement in postural stability in both study intervention groups with the group who just used AposTherapy without any addition exercise showing a higher effect. Utilising foot-worn biomechanical interventions may be an efficient method for mitigating the risks of ACL injury
ROCK CLIMBING HELMET IMPACT PERFORMANCE VARIES BY HELMET MODEL TYPE
Get PDFThe purpose of this study was to compare the impact performance of a sample of rock climbing helmets. Each helmet was impacted at three locations (front, side, and back) and three impact speeds (2 m/s, 3.85 m/s, and 5 m/s) using a custom pendulum impactor. Peak resultant linear and rotational accelerations were compared by impact speed. The results of this study show that acceleration varies by helmet model and impact location. Differences in acceleration by helmet model support the need for relative performance ratings of rock climbing helmets. These tests can be used as the basis of methods to compare relative helmet performance. Relative performance evaluation would inform consumers of the safety of different helmet types, and would also inform manufacturers where improvements in helmet designs should be made
WHOLE BODY DYNAMIC POSTURAL CONTROL DURING BEND RUNNING
Get PDFBend running on an indoor track is influenced by differing structural constraints including banking and radii of the curve. Regardless of these constraints, an athlete must preserve whole-body postural control to maintain their running speed. The purpose of this study was to investigate the extent to which banking (banked v flat) and radii (lane 2 v lane 4) of a 200m indoor track influences whole centre of mass (CoM) during sprint running. When running in both lane 2 and lane 4, athletes’ CoM was closer to their inside foot when the track was banked compared to flat (p \u3c 0.05, 0-100% of stance). In conjunction with increased CoM anterior velocity identified for the banked condition (p \u3c 0.05, 0-100% of stance), the findings highlighted banking of the curve to be the preferable structural constraints for whole-body postural control, compared to a flat track
LOWER BODY MUSCULOTENDON UNIT FUNCTION DURING BOUNDING, HURDLE JUMPING AND RUNNING
Get PDFTo facilitate exercise prescription, this study compared the function of six lower limb musculotendon units during plyometric exercises with running. Fourteen distance runners performed overground running (3.89 m/s), bounding, and hurdle jumps. Computational simulations were used to compare musculotendon unit function, peak powers, and total work. Compared to running, the hurdle jumps had greater gluteus maximus peak power absorption (12.1%; SMD 0.65), and gluteus maximus (15.7%; SMD 0.51) and soleus (16.5%; SMD 0.92) total negative work. Hurdle jumps may be an appropriate exercise when higher eccentric loads of the gluteus maximus and soleus are required. Compared to running, bounding had increased gastrocnemius total negative work (63.8%; SMD 0.81) and may be suitable when eccentric overload of the gastrocnemius is desired
MEDIO-LATERAL ACCELERATION OF FEMALE ATHLETES WITH AN ACL RECONSTRUCTION IN COMPARISON WITH A HEALTHY POPULATION
Get PDFWe assessed change of direction abilities in team sport female athletes. Ten participants returned to full activity from ACL reconstruction (ACLR) for longer than one year and 10 healthy controls (CON) were compared. Twelve maximal effort 45° cutting manoeuvres from the reconstructed side (ACLR) or a random selection of both sides (CON) were analysed for each individual using a motion capture system. CON showed greater medio-lateral centre of mass (COM) acceleration between 51 and 75 % of ground contact. CON reported increased ankle plantar flexor power from 94 to 98 % of foot contact, with also a higher peak. Although cleared to return to full activity, biomechanical differences associated with performance were still present in the ACLR group, which may have implications for better targeting rehabilitation practice
EXPLOSIVE PLANTAR FLEXOR PERFORMANCE: A COMPARISON OF ELITE SPRINTERS VERSUS PHYSICALLY ACTIVE INDIVIDUALS
Get PDFThis study examined differences in explosive muscular torque production of the plantar flexors of participants with differing training backgrounds. Explosive performance of a group of elite sprinters (n = 14) and physically active individuals (n = 14) were examined during explosive and maximal isometric contractions across different muscle-tendon unit (MTU) lengths. The rate of torque development (RTD) across time windows (0-50, 50-100, 100-150 ms) and maximal voluntary torque (MVT) was measured. Sprinters exhibited greater early phase RTD (0-50, 50-100 ms) across MTU lengths. Relative MVT was greater for sprinters at the dorsiflexed MTU length only. The results suggest sprint-specific training contributes to the improved explosive performance of the plantar flexors across MTU lengths, particularly in the early phase of muscular contraction
ASSESSMENT OF KINEMATIC CMJ DATA USING A DEEP LEARNING ALGORITHM-BASED MARKERLESS MOTION CAPTURE SYSTEM
Get PDFThe purpose of this study was to compare the performance of a video-based markerless motion capture system to a conventional marker-based approach during a counter movement jump (CMJ). Twenty-three healthy participants performed CMJ while data was collected simultaneously via a marker-based (Oqus) and a 2D video-based motion capture system (Miqus, both: Qualisys). The video data was further processed to 3D-data using Theia3D (Theia Markerless Inc.). Excellent agreement between systems with ICCs \u3e0.99 exists for jump height (mean average error of -0.27 cm) and sagittal ankle and knee plane angles (RMSD \u3c 5°). The hip joint showed an average RMSD of 21° with a strong correlation of 0.80. As such the markerless system is capable of detecting jump height, sagittal ankle and knee joint angles and 3D joint positions of a CMJ to a high accurac
INFLUENCE OF LANDING QUADRANT ON ELLIPTICAL ORBIT AND ITS REALTION TO RELEASE PARAMETERS OF THE HAMMER THROW
Get PDFHammer throw official distance is determined by the velocity, angle, and height of the hammer at release, which is regulated by the acceleration arc of the hammer during the turns. This study aimed to examine the influence of position variables describing the elliptical orbit during each turn on the official distance and the release parameters. Competitive hammer throws from 35 athletes (17 men and 18 women) were digitized to obtain 3-D coordinates of the thrower and the hammer throughout the throw. Multiple regression models indicate that hammer positioning during turns 1 and 2 accounts for the greatest variance in the official distance. Male throwers use the acceleration arc to regulate the release angle throughout the throw, whereas female throwers use the acceleration arc to regulate both release velocity and release angle throughout the throw
Cutting Sex-Performance Differences Down to Size: Are Females Closer to Males in Shorter Sprint Races?
Get PDFThe body size and composition differences between men and women are set by genetic factors with relatively constant offsets, particularly in homogeneous athletic populations. However, performance differences between the sexes appear to be more variable, potentially due to the mechanical demands of different events. Here, we set out to analyse the sex performance differences across sprint running events that differ in mechanical demands due to race length. Based on the scaling of tissue areas in relation to body mass, shorter, smaller athletes should be more forceful per kg body mass than larger ones. Greater force per kg body mass capabilities should be most advantageous during the acceleration portion of any race. Therefore, we hypothesized that the shorter sex, would fare relatively better in shorter vs longer races. We tested this by gathering performance, height and mass data from open sources on the top 40 performers in the 60, 100, 200 and 400 meter races over a 15 year period. As hypothesized, the shorter the sprint race, the smaller the male-female performance difference. These differences ranged from 8.6% at 60 m to 10.9% at 400 m. We conclude that male-female performance differences appear to be smaller for accelerated vs. steady-speed running