Running patterns for male and female competitive and recreational runners based on accelerometer data

The purpose of this study was to classify runners in sex-specific groups as either competitive or recreational based on center of mass (CoM) accelerations. Forty-one runners participated in the study (25 male and 16 female), and were labeled as competitive or recreational based on age, sex, and race performance. Three-dimensional acceleration data were collected during a 5-minute treadmill run, and 24 features were extracted. Support vector machine classification models were used to examine the utility of the features in discriminating between competitive and recreational runners within each sex-specific subgroup. Competitive and recreational runners could be classified with 82.63 % and 80.4 % in the male and female models, respectively. Dominant features in both models were related to regularity and variability, with competitive runners exhibiting more consistent running gait patterns, but the specific features were slightly different in each sex-specific model. Therefore, it is important to separate runners into sex-specific competitive and recreational subgroups for future running biomechanical studies. In conclusion, we have demonstrated the ability to analyze running biomechanics in competitive and recreational runners using only CoM acceleration patterns. A runner, clinician, or coach may use this information to monitor how running patterns change as a result of training.     

Light distribution from rectangular sources

The rectangular light source is more frequently encountered in engineering practice than any other form. Thus, both for artificial lighting and natural lighting, it is desirable to have convenient methods of obtaining the light distributions produced by rectangular sources. We have attempted to supply this need by calculating pharosage from sources of uniform helios and also for the non-uniform sources representing average overcast skies. Figures 5 to io are found to be particularly convenient in the visualization of light distributions.The results of these graphs are readily extended to any point and to surfaces tilted at any angle, provided that the plane of the illuminated surface does not cut the source.In conclusion, we wish to express our appreciation of the careful work of the computers: Messrs. L. S. Castlemann M. S. Cettei, J. C. Gibbs, A. L. Keller, G. J. Laurent, V. Lippitt, J. M. Margolskee, L. Mautner, J. Topalian.     

Radiant Flux Through Apertures— II

Equations for the radiant flux through apertures are well-known. But the exact equations are cumbersome and give little direct insight into the behavior of aperture systems. The present paper considers simple approximate equations for rectangular apertures in parallel planes and in perpendicular planes. It extends the previous work (square apertures) to the general case of rectangular apertures.     

Physical,physiological, and technical demands of national netball umpires at different competition levels

ABSTRACT

To compare demands of national netball umpires between levels of competition, 22 Netball New Zealand high-performance umpires participated in this investigation. These included from highest to lowest standard: 9 × semi-professional ANZ Championships (ANZC); 6 × National A Squad (NZA); and 7 × National Development Squad (DEV). Physical (global positioning system tri-axial accelerometry), physiological (heart rate) and technical (video analysis) demands were determined for 48 (16 per group) umpire match performances. Level of competition had no significant effect on physical or mean physiological demands. However, ANZC umpires spent a lower proportion of time at low heart rates compared to DEV, and a greater proportion of time at high, rather than moderate, heart rates compared to NZA. Compared to lower standard umpires, ANZC spent lesser proportions of time standing but greater proportions of time walking backwards and sideways, and turning to change direction. Furthermore, ANZC umpires spent lower proportions of time jogging, but greater proportions of time sprinting compared to DEV. Finally, ANZC umpires spent longer mean durations than DEV on the goal third side line. As such, the difference in demands experienced by national netball umpires between levels of competition is more technical than physical or physiological.     

Physical movement demands of elite-level netball match-play as measured by an indoor positioning system

ABSTRACT

Physical movement demands in elite netball match-play have been limited to notational analysis or accelerometer-derived measures, due in part to the indoor environment in which they are played. Commercially available local positioning systems (LPS) using ultra-wideband communication have been designed to bring similar capabilities as global positioning systems (GPS) to indoor environments. This study aims to quantify both spatiotemporal and traditional accelerometer-derived measures, to assess the movement demands of all playing positions, during Australian national netball league matches. Total distance, metreage per minute, acceleration density, acceleration density index, acceleration load, jumps, velocity bands, acceleration bands and PlayerLoad variables have been presented for each position. Mean total distance-covered in match-play differed substantially between positions. Centre position accumulated the highest mean distance (5462.1 ± 169.4 m), whilst the Goal Shooter consistently covered the lowest mean distance (2134 ± 102.6 m). Change of direction relative to movement area was highest for the two most restricted positions based on average acceleration per 10 m covered during match-play (Goal Shooter; 7.21 ± 0.88 m · s ^{? 2} and Goal Keeper; 6.75 ± 0.37 m · s ^{? 2}, remaining positions; 5.71 ± 0.14 m · s ^{? 2}). The positional profiles outlined in this study can assist skill and conditioning coaches to prescribe training sessions that will optimise the athlete’s physical preparation for the demands of competition.