Muscle activation sequencing of leg muscles during linear glide shot putting

In the shot put, the athlete’s muscles are responsible for generating the impulses to move the athlete and project the shot into the air. Information on phasic muscle activity is lacking for the glide shot put event and therefore important technical information for coaches is not currently available. This study provides an electromyography (EMG) analysis of the muscle activity of the legs during shot put. Fifteen right-handed Irish national level shot putters performed six maximum effort throws using the glide shot put technique. EMG records of eight bilateral lower limb muscles (rectus femoris, biceps femoris, medial- and lateral-gastrocnemius) were obtained during trials. Analysis using smooth EMG linear envelopes revealed patterns of muscle activity across the phases of the throw and compare men and women performers. The results showed that the preferred leg rectus femoris, the preferred leg biceps femoris and the non-preferred leg biceps femoris play important roles in the glide technique, with the total duration of high volumes of activity between 34 and 53% of the throw cycle. A comprehensive understanding of movement and muscle activation patterns for coaches could be helpful to facilitate optimal technique throughout each of the key phases of the event.     

Canoe slalom--competition analysis reliability

The aim of this study was to assess intra-observer and inter-observer reliability of data gathered from a lapsed-time time-motion analysis of canoe slalom competition. The data were collected using a definition set developed in conjunction with elite canoe slalom coaches. Competition runs from four national-standard paddlers in a national selection race were analysed in random order three times by three observers. For each run, observers identified various events specific to canoe slalom, including time taken between gates, touched and missed gates, turn times, major and minor avoidance, rolls, paddle in and out of water times, and stroke classification. The error of measurement was determined for each of these variables. For time taken between gates and turn times, the error was < or = 0.21 and < or = 0.39 s for intra-observer and inter-observer analysis, respectively. The error for stroke in and out of water times was < or = 0.08 and < or = 0.13 s for intra-observer and inter-observer analysis, respectively. Analysis of stroke classification identification for intra-observer comparisons revealed that 91% of the time identical stroke identification occurred. Inter-observer analysis revealed identical stroke identification was achieved 81% of the time. These reliability data compare favourably with previous time-motion analysis in other sports using fewer variables.     

Agreement between polar and SRM mobile ergometer systems during laboratory-based high-intensity, intermittent cycling activity

The purpose of this study was to assess the agreement between two mobile cycle ergometer systems for recording high-intensity, intermittent power output. Twelve trained male cyclists (age 31.4 +/- 9.8 years) performed a single 3 min intermittent cycle test consisting of 12 all-out efforts, separated by periods of passive recovery ranging from 5 to 15 s. Power output was recorded using a Polar S710 heart rate monitor and power sensor kit and an SRM Powercrank system for each test. The SRM used torque and angular velocity to calculate power, while the S710 used chain speed and vibration to calculate power. Significant differences (P < 0.05) in power were found at 8 of the 12 efforts. A significant difference (P = 0.001) was also found when power was averaged over all 12 intervals. Mean power was 556 +/- 102 W and 446 +/- 61 W for the SRM and S710 respectively. The S710 underestimated power by an average of 23% with random errors of */[division sign] 24% when compared with the SRM. Random errors ranged from 36% to 141% with a median of 51%. The results indicate there was little agreement between the two systems and that the Polar S710 did not provide a valid measure of power during intermittent cycling activity when compared with the SRM. Power recorded by the S710 system was influenced greatly by chain vibration and sampling rates.     

Relationship between performance-based and laboratory tests for lower-limb muscle strength and power assessment in healthy older women

The aim of the study was to assess the relationship between performance-based and laboratory tests for muscular strength and power assessment in older women. Thirty-two women aged 68.8 +/- 2.8 years were recruited. All participants were asessed for: (a) two performance-based tests--the box-stepping test (mean 296 +/- 51 J) and two-revolution maximum test (mean 7.1 +/- 2 kg) performed while pedalling on a cycle ergometer; and (b) muscular function tests--maximal instantaneous peak power jumping on a force platform (mean 1528 +/- 279 W); maximal voluntary contraction (MVC) during knee extension (mean 601 +/- 571 N) and leg press (mean 626 +/- 126 N), and leg press power (mean 483 +/- 98 W) on a dynamometer. Using univariate analysis, performance-based tests were compared with laboratory muscle strength and power measurements. Muscle power correlated most strongly with the performance-based tests for both jumping and leg press power (r-values between 0.67 and 0.75; P < 0.01). The correlation with muscle strength measures ranged between 0.48 and 0.61 (P < 0.01). The proposed tests may have particular relevance in geriatric and rehabilitation environments as they represent an easy, practical, and inexpensive alternative for the assessment of muscular strength and power.     

A practical observation procedure for monitoring four behaviors relevant to classroom management

The authors present a quick and simple procedure for observing four behaviors relevant to classroom management: student disruption, student attention, and the teacher's use of both positive and negative events. Five paraprofessional teacher aides observed 28 elementary and middle-school teachers and their classes on 10 occasions both at the beginning and at the end of the school year. The paraprofessional aides, quickly trained, manifested high interrater reliabilities. Stable estimates of all four target behaviors were obtained by averaging the data from only four or five consecutive observations. Strong, consistent intercorrelations between the four behaviors were found, and the intercorrelations were in the expected directions. Thus, the procedure yields reliable, stable measures of four important classroom behaviors, and it is practical to use.     

Measuring knowledge creation in virtual teams through the social network analysis

The current literature regarding virtual teams (VTs) lacks outcomes related to intellectual capital (IC) and knowledge management (KM). Moreover, e-collaboration and VTs need the necessary metrics to assess the real benefits that KM derives from the use of new e-collaboration technologies. There is also scarce evaluation of the cause–effect linkage between a VT structural configuration and its creative performance. Following this lead, we propose an evaluation method based on social network analysis (SNA) and indexes referring to knowledge creation. The paper concludes with an application on a real case study that shows how this methodology can be used as a KM tool to increase the creative output of VTs.     

The Rhythm of the University: Part One - Teaching, Learning, and Administering in the Whiteheadian Vein

This is the first of two articles examining Alfred North Whitehead's notion of the rhythm of the university. Here, I concentrate on the rhythm of teaching and learning, the importance of academic freedom to an imaginative faculty, and the relationship between Whitehead's own pedagogy and his considerable administrative practice. My purpose is to show how his views enlarge our understanding of universities today.