ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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INFLUENCE OF A SEASON OF ATHLETIC TRAINING ON LEG AND JOINT STIFFNESS IN HIGH LEVEL NETBALLERS
Get PDFThe purpose of this study was to ascertain the impact of a season of training on lower limb stiffness, joint stiffness and the contributing mechanisms during basic jumping and sports specific tasks. Eleven high level female netballers completed a maximal countermovement jump (basic), 50 m sprint and change of direction cutting task (sports specific) prior to and following a competition/training season. Student paired t-tests or their non-parametric equivalent identified no pre-post season stiffness changes, however stiffness mechanism changes during sports specific tasks did occur
ALTERATIONS IN JOINT KINEMATICS AND KINETICS DURING DOWNHILL RUNNING
Get PDFThe purpose of this investigation was to find how joint kinematics and kinetics during downhill running change compared to level running. Fifteen recreational runners ran on a force plate imbedded treadmill with three different slopes (0 º, -6º, and -9º) at a controlled speed of 3.2 m/s. Ten steps on each slope were selected for analysis. Increased knee flexion with decreased ankle plantar-flexion and hip flexion was found during downhill running compared to level running. Decreased peak propulsive ground reaction force and posterior impulse were found during downhill running compared to level running. Additionally, increased extension moment with increased negative joint power at the knee and decreased plantar-flexion moment with decreased negative joint power at the ankle were found during downhill running compared to level running
LOWER EXTREMITY LEAN MASS ASYMMETRY CORRELATED WITH FORCE AND POWER ASYMMETRY DURING JUMPING IN ADULTS
Get PDFThe purpose of the current study was to quantify the relationships between lower extremity lean mass asymmetry and force and power asymmetry during jumping in adults aged 18-75 years old. Forty younger adults (18-35 years of age), 28 middle-aged adults (36-55 years of age), and 34 older adult (56-75 years of age) participated in the study. Subjects underwent Dual Energy Xray Absorptiometry to assess lower extremity bilateral lean mass asymmetry. Subjects performed 3 trials of a counter movement jump on two force plates to measure lower extremity bilateral force and power asymmetry. Lower extremity lean mass asymmetry was significantly correlated with force and power asymmetry in younger and middle-aged adults, but not in older adults. Improving lean mass asymmetry might assist in correcting force asymmetry in younger and middle-aged adults
LONGITUDINAL MONITORING OF COUNTERMOVEMENT JUMP MECHANICAL VARIABLES: A PRILIMINARY INVESTIGATION
Get PDFThe purpose of this study was to examine the influence of accumulated volume load on countermovement jump (CMJ) mechanical variables. Eight athletes underwent weekly CMJ testing using a force plate. Statistical changes were observed in certain CMJ variables over the observation period. Jump height (0.42±0.05 m) and allometrically scaled peak power (88.86±7.49 W·kg-0.67) exhibited multiple statistical changes. These changes appeared to exhibit a delayed effect in response to accumulated volume load. Specifically, following several weeks of large accumulated volume loads these variables declined. In addition subsequently decreasing accumulated volume loads resulted in an increase in both variables. The findings of this study indicate measuring jump height and peak power may be an effective method for monitoring a resistance training process
THE RELATIONSHIP BETWEEN HAMSTRING MUSCULO-ARTICULAR STIFFNESS AND LOWER-EXTREMITY BODY COMPOSITION
Get PDFThe purpose of this study was to compare hamstring musculo-articular stiffness (MAS) and lower extremity (LE) body composition in the dominant (D) and non-dominant (ND) legs of men and women, and then to examine relationships between MAS and LE body composition while controlling for sex. No differences in MAS or LE body composition were found between D and ND legs in either sex. Males demonstrated greater MAS and LE % lean mass (%LM) than females, while females had greater LE % fat mass (%FM) than males. The combination of sex and %FM explained ~60% of the variance in MAS, while ~31% of the variance could be attributed to sex alone. Findings suggest that between-sex differences may potentially mask relationships between MAS and the factors influencing this measure, highlighting the need for future sex-stratified designs
COMPARISON OF METHODS FOR ASSESSING VERTICAL JUMP HEIGHT PERFORMANCE
Get PDFRelationships, explained variance, measurement error, and limits of agreement were examined among field and laboratory countermovement vertical jump tests, including Vertec, 3D video, and force platform data. Data were simultaneously collected on a single countermovement jump trial for 13 female varsity volleyball players. Vertical jump height computed using maximum centre of mass (COM) velocity from force platform data demonstrated the greatest precision, as well as the strongest correlation (r=0.90), greatest explained variance (R2=0.81), and lowest standard error of the estimate (0.02m) in vertical 3D video COM displacement. Jump height calculation using maximum COM velocity may highlight relevant performance measures, providing jump height estimations more quickly and easily, and with greater precision via force platform analysis
COMPARATIVE GAIT ANALYSIS BETWEEN CHILDREN WITH AUTISM AND AGE MATCHED CONTROLS
Get PDFThere are very few studies that have analyzed the gait of children with autism. The purpose of this study was to investigate gait of children with autism using temporal-spatial variables. Fifteen children with autism and fifteen age matched typically developing children walked 3 times on the GAITRite® system. Dependent variables were statistically analyzed using independent samples t-tests with Bonferroni adjustments. Results show a reduction in cadence, gait velocity, step length and an increase in step width for the children with autism. In conclusion, our results suggest that the children with autism have abnormal gait compared to age matched controls
THE EFFECT OF A COMMON COACHING CUE ON BODY KINEMATICS IN THE TENNIS SERVE
Get PDFThe objective of this study was to quantify the kinematic changes promoted by instructing players to implement a common coaching constraint, an arabesque finish position, in the tennis serve. A 10 camera 500 Hz 3D VICON MX motion analysis system recorded the service action of 8 elite junior players as they performed 3 normal serves and 3 serves with an arabesque finish. The arabesque finish promoted greater frontal plane trunk range of motion and angular velocity (shoulder over shoulder rotation) as well as increased leg drive; variables established as important in the development of serve speed. Instructing players to finish in an arabesque position can therefore be considered an effective way to elicit the desired kinematic change, and is consequently an effective instructional cue
BIOMECHANICAL ANALYSIS OF TAEKWONDO ROUNDHOUSE KICK FOCUSED ON PHASE BEFORE TOE OFF
Get PDFThe purpose of this study was to clarify the biomechanical taekwondo roundhouse kick (RHK) mechanism of the lower half of the body in the phase before toe off the floor (READY phase) focusing especially on techniques for producing faster kicking speed and shortened time of kicking. The results were summarized as follows: i) motion of hip joint in support leg had relation to the flow of mechanical energy to pelvis, ii) extension of hip joint in support leg produced the translational velocity of pelvis, and iii) players accomplished motion of hip joint extension by providing the torque of hip joint extension in support leg at early time. Taken together, our data suggests that coaches should pay greater attention to support leg and READY phase in order to improve the players’ kicking technique for kicking fast and quick
APPLICATIONS OF FUNCTIONAL DATA ANALYSIS IN SPORT BIOMECHANICS
Get PDFThis paper reconsiders the challenge of analysing coordination in human movement with particular emphasis on the application of Functional Data Analysis and Functional Principal Component Analysis. The process of Functional Data Analysis is outlined using examples from biomechanics of sports injuries and coordination in race-walking, jumping and running. The evolution of the spring mass model used to describe jumping and hopping behaviour is examined and it is proposed that this model represents a coordination structure in human movement which may be appropriately analysed using Functional Data Analysis methods