COORDINATION VARIABILITY IN OVERGROUND RUNNING AND WALKING AT PREFERRED AND FIXED SPEEDS

Coordination variability (CoordV) is impacted by the type and speed of locomotion, however, the appropriate number of trials required for stable outputs during overground locomotion is yet to be determined. The purpose of this study was to analyse the CoordV of lower limb segment and joint couplings to determine the number of trials needed for a stable mean during running and walking at preferred and fixed speeds. Three-dimensional lower-limb kinematics were captured for recreational runners (n = 10) performing 20 trials of each condition. Using a modified vector coding technique, segment and joint couplings were derived, from which, CoordV was calculated using circular statistics. The number of trials required to achieve a mean within 100±10% of a 20 stride mean was determined for each individual. The study findings indicate the need for between 8 and 9 trials to produce a stable mean and contribute to reliable biomechanical outputs

WHOLE-BODY CONTROL STRATEGIES DURING ANTICIPATED AND UNANTICIPATED SIDESTEP MANOEUVRES PERFORMED BY FEMALES AND MALES

The purpose of this study was to investigate the influence of sex and planning time on spatial and temporal-level whole-body centre of mass (CoM) mechanics during the performance of the sidestep manoeuvre. Nine female and nine male collegiate team sport athletes completed seven anticipated and seven unanticipated sidestepping trials, during which three-dimensional CoM data were recorded. In addition to having a lower vertical CoM position during the preparatory phase (p \u3c 0.05), female athletes were found to have lower anterior-posterior velocity, but greater vertical velocity during the stance phase in comparison with their male counterparts (p \u3c 0.05). The findings provide evidence that female and male athletes utilise different whole-body dynamic control strategies to perform both anticipated and unanticipated sidestep manoeuvres

Towards a theoretical determination of the geographical probability distribution of meteoroid impacts on Earth

Tunguska and Chelyabinsk impact events occurred inside a geographical area of only 3.4\% of the Earth's surface. Although two events hardly constitute a statistically significant demonstration of a geographical pattern of impacts, their spatial coincidence is at least tantalizing. To understand if this concurrence reflects an underlying geographical and/or temporal pattern, we must aim at predicting the spatio-temporal distribution of meteoroid impacts on Earth. For this purpose we designed, implemented and tested a novel numerical technique, the "Gravitational Ray Tracing" (GRT) designed to compute the relative impact probability (RIP) on the surface of any planet. GRT is inspired by the so-called ray-casting techniques used to render realistic images of complex 3D scenes. In this paper we describe the method and the results of testing it at the time of large impact events. Our findings suggest a non-trivial pattern of impact probabilities at any given time on Earth. Locations at $60-90\deg$ from the apex are more prone to impacts, especially at midnight. Counterintuitively, sites close to apex direction have the lowest RIP, while in the antapex RIP are slightly larger than average. We present here preliminary maps of RIP at the time of Tunguska and Chelyabinsk events and found no evidence of a spatial or temporal pattern, suggesting that their coincidence was fortuitous. We apply the GRT method to compute theoretical RIP at the location and time of 394 large fireballs. Although the predicted spatio-temporal impact distribution matches marginally the observed events, we successfully predict their impact speed distribution.Comment: 16 pages, 11 figures. Accepted for publication in MNRA

JOINT KINEMATICS DURING INDOOR BEND SPRINTING

The aim of this study was to identify the effect of radius on lower extremity joint kinematics during indoor bend sprinting. Kinematic data (250 Hz) were collected from eight well-trained sprinters during two ~80 m sprints in banked lanes 2 and lane 4. One-dimensional Statistical Parametric Mapping was used to analyse lower extremity joint kinematics during the stance phase. Similar to previous bend sprinting research, this study found the left limb appears to adopt an adduction and eversion strategy during left stance to control the movement demands of bend sprinting. Furthermore, significant inter-limb asymmetry occurred primarily in lane 2, highlighting that tightening the radii of the lane brought about increased inter-limb asymmetry

AN INVESTIGATION INTO THE EFFECT OF LANE RADIUS ON STEP CHARACTERISITCS IN INDOOR BEND SPRINTING

The study aimed to identify the effect of radius on step characteristics during bend sprinting. Eight sprinters undertook two ~80 m sprints in two different conditions through two capture areas (straight and bend) collecting whole-body kinematic data. Step Velocity on the straight was lower than Lane 2 on the bend for the left-to-right step, brought about by a greater Step frequency (SF). Right-to-left SF was significantly lower in Lane 4 in comparison to the straight due to a greater step time. Step time was greater in Lane 4 for the right step compared to Lane 2. A greater SF was observed for the left step compared to the right step in Lane 4 whilst a greater flight time was seen for the left step in Lane 2. Therefore, lane radius typical of indoor competition elicits performance changes during bend sprinting, warrenting further biomechanical analysis

WHOLE BODY DYNAMIC POSTURAL CONTROL DURING BEND RUNNING

Bend 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

Liver cancer survival in the United States by race and stage (2001-2009): Findings from the CONCORD-2 study.

BACKGROUND: Worldwide, liver cancer is a leading cause of death for both men and women. The number of Americans who are diagnosed with and die of liver cancer has been rising slowly each year. Using data from the CONCORD-2 study, this study examined population-based survival by state, race, and stage at diagnosis. METHODS: Data from 37 statewide registries, which covered 81% of the US population, for patients diagnosed during 2001-2009 were analyzed. Survival up to 5 years was adjusted for background mortality (net survival) with state- and race-specific life tables, and it was age-standardized with the International Cancer Survival Standard weights. RESULTS: Liver cancer was diagnosed overall more often at the localized stage, with blacks being more often diagnosed at distant and regional stages than whites. 5-year net survival was 12.2% in 2001-2003 and 14.8% in 2004-2009. Whites had higher survival than blacks in both calendar periods (11.7% vs 9.1% and 14.3% vs 11.4%, respectively). During 2004-2009, 5-year survival was 25.7% for localized-stage disease, 9.5% for regional-stage disease, and 3.5% for distant-stage disease. CONCLUSIONS: Some progress has occurred in survival for patients with liver cancer, but 5-year survival remains low, even for those diagnosed at the localized stage. Efforts directed at controlling well-established risk factors such as hepatitis B may have the greatest impact on reducing the burden of liver cancer in the United States. Cancer 2017;123:5059-78. Published 2017. This article is a U.S. Government work and is in the public domain in the USA