THE CONTRIBUTION OF BODY CENTER OF MASS VELOCITY TO BASKETBALL BALL RELEASE VELOCITY ACROSS SHOT DISTANCES

This study investigated the contribution of the body center of mass velocity to basketball ball velocity at release when taking shots from different distances from the hoop. Seven basketball players with ten years of experience performed at least ten shots from progressively greater distances: close (\u3c 2.5 m), medium (4.57 m, free throw line), and long (6.02 m, American high school three-point line). As the distance from the hoop increases, the ball velocity required at release increases. Our hypothesis was that an increase in the shot distance would increase the contribution of the body center of mass velocity to ball velocity at release was hypothesized. Kinematics of the ball were recorded using video. Reaction forces generated by each leg were measured using two force plates and used to determine the velocity of the body center of mass during the shooting motion. The results indicate that the percent contribution of the body center of mass velocity to ball velocity at release increased, and the arm contribution decreased with an increase in shot distance. Releasing the ball earlier in the body center of mass trajectory before the apex resulted in a greater percent body contribution of the center of mass vertical velocity to ball vertical velocity

DIFFERENCES IN REACTION FORCE-TIME CHARACTERISTICS EXPERIENCED BY FEMALES WHEN RUNNING ON A TRACK AT DIFFERENT SPEEDS

Elite collegiate runners are susceptible to sustaining lower extremity stress related injuries. Ground reaction forces (GRFs) were analyzed to understand differences in mechanical loading at steady state 5.5 and 7 min/mile paces. We hypothesized GRF magnitudes would increase with speed while horizontal GRFs during braking would be unique to each participant. GRFs, inertial measurement units, and high speed video were collected during outdoor over ground running. Group differences were observed that were not always significant within participant. As speed increased, average horizontal GRF during braking (-0.25 to -0.29 BWs) decreased while peak vertical GRF increased (2.75 to 2.91 BWs). The unique pattern of the sagittal plane resultant GRF orientation was maintained during initial braking phase which may indicate this orientation is a nervous system control priority

Wheeled Mobility Biomechanics

For the manual wheelchair (MWC) user, loss of lower extremity function often places the burden for mobility and activities of daily living on the upper extremities. This e-book on Wheeled Mobility Biomechanics contains current research that provides insights into the mechanical demands and performance techniques during tasks associated with MWC. Our intent was to contribute to advancing the knowledge regarding the variables that promote or hinder an individual’s capacity to handle the daily manual wheeled mobility demands and gain greater insights into upper extremity loading consequences, predictors of pain onset and injury, and ultimately identify strategies for preserving health and functional mobility for the MWC user

FE sensitivity models and descriptions for Tseng et al.

Tsengetal_PLoS-ONE_FE_models.zip: Finite element models of Gray Wolf mandible sensitivity analysis. Data uploaded by Zhijie Jack Tseng, contact: [email protected]. Zipped file contains sensitivity models J20101112TSA01 to J20101215TSA44. Files include finite element mesh (.st7) and model details and result sheets (.xls) for each model. 2011032

Data from: Model sensitivity and use of the comparative finite element method in mammalian jaw mechanics: mandible performance in the Gray Wolf

Finite Element Analysis (FEA) is a powerful tool gaining use in studies of biological form and function. This method is particularly conducive to studies of extinct and fossilized organisms, as models can be assigned properties that approximate living tissues. In disciplines where model validation is difficult or impossible, the choice of model parameters and their effects on the results become increasingly important, especially in comparing outputs to infer function. To evaluate the extent to which performance measures are affected by initial model input, we tested the sensitivity of bite force, strain energy, and stress to changes in seven parameters that are required in testing craniodental function with FEA. Simulations were performed on FE models of a Gray Wolf (Canis lupus) mandible. Results showed that unilateral bite force outputs are least affected by the relative ratios of the balancing and working muscles, but only ratios above 0.5 provided balancing-working side joint reaction force relationships that are consistent with experimental data. The constraints modeled at the bite point had the greatest effect on bite force output, but the most appropriate constraint may depend on the study question. Strain energy is least affected by variation in bite point constraint, but larger variations in strain energy values are observed in models with different number of tetrahedral elements, masticatory muscle ratios and muscle subgroups present, and number of material properties. These findings indicate that performance measures are differentially affected by variation in initial model parameters. In the absence of validated input values, FE models can nevertheless provide robust comparisons if these parameters are standardized within a given study to minimize variation that arise during the model-building process. Sensitivity tests incorporated into the study design not only aid in the interpretation of simulation results, but can also provide additional insights on form and function

Data from: Model sensitivity and use of the comparative finite element method in mammalian jaw mechanics: mandible performance in the Gray Wolf

Finite Element Analysis (FEA) is a powerful tool gaining use in studies of biological form and function. This method is particularly conducive to studies of extinct and fossilized organisms, as models can be assigned properties that approximate living tissues. In disciplines where model validation is difficult or impossible, the choice of model parameters and their effects on the results become increasingly important, especially in comparing outputs to infer function. To evaluate the extent to which performance measures are affected by initial model input, we tested the sensitivity of bite force, strain energy, and stress to changes in seven parameters that are required in testing craniodental function with FEA. Simulations were performed on FE models of a Gray Wolf (Canis lupus) mandible. Results showed that unilateral bite force outputs are least affected by the relative ratios of the balancing and working muscles, but only ratios above 0.5 provided balancing-working side joint reaction force relationships that are consistent with experimental data. The constraints modeled at the bite point had the greatest effect on bite force output, but the most appropriate constraint may depend on the study question. Strain energy is least affected by variation in bite point constraint, but larger variations in strain energy values are observed in models with different number of tetrahedral elements, masticatory muscle ratios and muscle subgroups present, and number of material properties. These findings indicate that performance measures are differentially affected by variation in initial model parameters. In the absence of validated input values, FE models can nevertheless provide robust comparisons if these parameters are standardized within a given study to minimize variation that arise during the model-building process. Sensitivity tests incorporated into the study design not only aid in the interpretation of simulation results, but can also provide additional insights on form and function