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RELATIONSHIPS BETWEEN WHOLE-BODY KINEMATICS AND BADMINTON JUMP SMASH RACKET HEAD SPEED
Get PDFThe purpose of this study was to identify kinematic determinants of shuttlecock speed in the badminton jump smash. Three-dimensional kinematic (400 Hz) data were collected for 18 experienced male badminton players using an 18 camera Vicon Motion Analysis System. Each participant performed 12 jump smashes. The trial with the fastest shuttlecock speed per participant was analysed using an 18-segment rigid body model. Parameters were calculated describing elements of the badminton jump smash technique. Four kinematic variables were significantly correlated with racket head speed. Greater peak wrist joint centre linear velocity, jump height, shorter acceleration phase, and greater shoulder internal rotation at shuttlecock / racket impact
THE INFLUENCE OF DYNAMIC AND PLYOMETRIC EXERCISES ON KNEE JOINT MOTION FOR COUNTERMOVEMENT JUMP PERFORMANCE.
Get PDFThis study aims to analyse the effects of dynamic and plyometric exercises on knee joint motion for countermovement jump (CMJ) performance. The CMJ test was performed on 45 college male non-athletes who were categorised into three groups; a dynamic group (DG) performing dynamic exercises, a plyometric group (PG) performing jumping exercises, a control group (EG) performing traditional exercises for physical education. Motion analysis data from the knee joint angles were obtained during countermovements in the sagittal plane using video recording. The results showed that plyometric and dynamic exercises could improve jumping performance in college non-athletes and enhance the strength, force, and power of lower limb muscles and joints. Furthermore, the motion analysis helped identify a range of motions in knee joints, dynamic, and plyometric exercises that contribute to jumping performance
EFFECT OF A NEUROMUSCULAR HOME TRAINING PROGRAM ON DYNAMIC KNEE VALGUS (DKV) IN LATERAL SINGLE-LEG LANDINGS
Get PDFThe purpose of the study was to investigate if an intervention program with focus on neuromuscular and feedback training in a home-based setting with supervision improves the leg alignment in recreational volleyball and basketball players. 16 players ran a 6-week neuromuscular intervention program in a home setting with video-based supervision. The control group just followed the regular training program. Before and after the intervention the DKV was measured as the peak knee valgus angle during the video-recorded landing after a lateral jump from a box using a 2D video analysis tool. While the DKV improved in the training group, no changes were found for the control group. The intervention was effective and can be recommended as a knee-injury mitigation program
THE ROLE OF SKELETAL MUSCLE-SYNTHESIZED BRAIN DERIVED NEUROTROPHIC FACTOR IN THE MAINTENANCE OF MOTOR NEURON MITOCHONDRIAL POPULATIONS
Get PDFMitochondria are essential for the high energy demands of the neuromuscular junction and, as a consequence, leave motorneurons susceptible to dysfunction. A potential origin of progressive pathology may be a reduction in brain-derived neurotrophic-factor (BDNF) signaling at the motor unit. We have shown that mice deficient in skeletal muscle-synthesized BDNF (msBDNF) demonstrate progressive motorneuron and muscle pathology at 120d. We hypothesize mitochondrial populations will be altered in motorneurons of msBDNF deficient-mice. At 117d, msBDNF deficient-mice received intramuscular injections of MitoTracker™ dye targeting the right gastrocnemius muscle. At 120d experimental groups underwent a gastrocnemius harvest or a sciatic nerve ligation protocol prior to sacrifice. In combination with MitoTracker™ injections, we used immunohistochemical labeling to target the mitochondrial translocase of outer membrane, TOM20. We used immunolabeling to further delineate mitochondrial populations within gastroc-associated motorneurons. To determine if experimental groups exhibit altered mitochondrial populations, we used confocal microscopy and IMARIS 3D rendering software. Immunolocalization was measured throughout the axon and axon terminals of motorneurons. We found no significant difference in mitochondrial populations within the pre-or post-synapse of control and msBDNF deficient animals. Results indicate that co-labeling mitochondria in a sciatic nerve ligation model illustrate mitochondrial population, as well as utility during transport. We found no significant difference in mitochondrial populations along the motor axon of msBDNF deficient mice at 120d. Ongoing studies suggest that mitochondrial populations and mobility may be as dynamic as mitochondrial function and assisted by the coexistence of several signaling mechanisms
A BLENDED DISPLACEMENT; STORIES FROM THE PERIPHERY
Get PDFA Blended Displacement; Stories from the Periphery, explores various forms and definitions of displacement through relationships, travel, and the sense of home. The thesis explores such subject matter as a creative work of mixed creative non-fiction and fiction. By engaging with controversial terms like expatriate, immigrant, refugee, and third-culture-kid, the work interrogates the political with the personal. The non-fiction part of the thesis centers on the narrative of a woman from Michigan living abroad, contrasting with the historical fiction portrayal of a Slovenian immigrant in Michigan. Both with ties to Michigan, both displaced, both illustrating the different labels, and both victims of abuse and domestic violence. To further show another perspective, included within the fiction component is the story of a Turkish woman living as an immigrant in the US. The entire work seeks to engage with many forms of displacement through the creative lens. While that sense of displacement is shown by location, the works delve deeper to illustrate being on the periphery in many cultural, familial, academic, and personal situations. The works interrogate the effects (positive and negative) that displacement and living on the periphery bring to both past and current events. By weaving personal narratives, the author seeks to not only bring about a greater understanding of complex issues, but also challenge the reader to question stereotypes. This includes questioning common beliefs in regards to abuse and domestic violence
DEVELOPMENT OF A LOW-COST IMU FOR SWIMMERS’ EVALUATION
Get PDFSwimmers improvement is built on rigorous and controlled training. This work aimed to develop a light-weight, practical and low-cost inertial measurement unit (IMU) for swimming monitoring. A 21g device was optimized for including the data acquisition hardware (based on an attitude and heading reference system – AHRS). Eleven male swimmers with different skill levels tested the system under the four different swimming strokes. Based on the AHRS data, three novel indicators were developed: trunk elevation, body balance and body rotation; and anayzed on an individual basis. The proposed unit has unique features to be further explored for training monitoring
KICK IMPACT FORCES FOR DIFFERENT RUGBY BALL SIZES, IMPACT POINTS AND INFLATIONS
Get PDFThe purpose of this study was to evaluate force characteristics of impact during kicking rugby balls of different size and inflation pressures and with different foot-ball contact positions. A mechanical kicking limb struck rugby balls of sizes 3 (smallest), 4 and 5 (used in senior competition). Foot and ball speed, contact time and distance and impact forces were calculated from 2D high speed video (4000 Hz). Overall, average contact force decreased as the ball size decreased. Decreasing inflation pressure also decreased average contact force. Finally, contacting the ball in the middle section produced lower forces than for similar kicks contacting the point of the ball. Manipulating ball size, inflation and contact position provides a platform for progressive kick-specific conditioning
BODY COMPOSITION COMPONENTS ARE RELATED TO VERTICAL JUMP KINETICS IN ELITE AMERICAN FOOTBALL PLAYERS
Get PDFAmerican football players vary in body composition across player positions. Components of body composition may affect jumping performance. The purpose of this study was to investigate the relationships between lean body mass, fat mass, total body mass, vertical jump (VJ) height, VJ reactive strength, and VJ kinetic asymmetry. 39 players had their body composition assessed using a BOD POD and VJ kinetics via a force plate. Pearson correlation coefficients quantified relationships between the variables, allpha =.05. VJ height and reactive strength were highly and very highly negatively associated with lean body mass, fat mass, and total body mass,
EFFECTS OF MINIMALIST FOOTWEAR ON THE LOWER LIMB LINEAR ACCELERATION AND ANGULAR VELOCITY DURING RUNNING
Get PDFThe purpose of this study was to explore if the tri-axial linear acceleration and angular velocity of knee and ankle joints differ between barefoot and minimal footwear running through investigating the extreme value difference. Eight participants were recruited for this experiment, acceleration parameters were measured utilizing IMU sensors. For the angular velocity, the minimum value in the frontal plane (p = 0.028) showed a decrease in the ankle joint. The minimal value in the sagittal plane and maximal value in the transverse plane (p = 0.001, p = 0) increased significantly. For the knee joint, the extreme values in the frontal plane increased (p = 0, p = 0), the maximal value increased and minimal value decreased with p = 0 and p = 0 in the sagittal plane. A significant decrease in the maximal value (p = 0) was exhibited in the transverse plane. The increased angular velocity may contribute to a result, with an insufficient arch support condition (minimalist shoes running) causing the foot’s intrinsic and extrinsic muscles and lower limb joints injury. These injuries should be a consideration for the novice minimalist runners
MUSCULAR CONTRIBUTIONS TO CENTER OF MASS ACCELERATION DURING COUNTERMOVEMENT JUMPS
Get PDFThe purpose of this study was to study the contributions of individual leg muscles and muscle groups to accelerate the body’s centre of mass (COM) during countermovement jumps (CMJ). Ten NCAA college basketball players performed maximal effort CMJ. Motion capture and ground reaction force data were recorded and used as inputs to a musculoskeletal model. The muscular contributions COM acceleration were quantified with three separate induced acceleration analyses (i.e., unit-force, maximum-force, and absolute-force analysis). All three analyses suggest that (in rank order of magnitude) the soleus, gastrocnemii, and vastii muscles exhibited the largest contributions to COM acceleration during CMJ