Movement Characteristics of Front Crawl Swimming at Sprint Pace and Middle-Distance Pace: Establishing Demands on the Torso Muscles

Dry-land training of the torso muscles is common in swimming programs; however, the role of the torso muscles in front crawl is unclear. The purpose of this thesis was to establish demands on the torso muscles in front crawl from analysis of kinematic data and torso muscle activity during sprint and middle-distance swimming. In the first two studies, 3D kinematic data were analysed from swimmers swimming at sprint and 400m pace. In Study 1, the range of hip roll decreased while shoulder roll range was similar as swimming speed increased. These differences produced greater range and velocity of torso twist as swimming speed increased, indicating higher demands on the torso muscles at sprint than at 400m pace. In Study 2, Fourier analysis was used to decompose angular momentum signals to determine the impact of the flutter kick on longitudinal body rotation. The third harmonic frequency, representing effects from the flutter kick, was greater in lower limb than in upper limb angular momentum at both paces, indicating a reduction in the rotation transferred from the lower to upper limbs. This reduction was more pronounced at sprint than at 400m pace. In Study 3, 3D kinematic data and surface EMG data from internal oblique, external oblique, rectus abdominis, and lumbar and thoracic erector spinae were collected from swimmers swimming at sprint and 400m pace. Torso twist angle did not relate to EMG data and no relationships between muscle activity and torso twist acceleration could be detected. Findings from this study indicate that the torso muscles may play a greater role in stability and posture than they do in producing torso twist in front crawl. Guidelines were developed to improve dry-land training specificity for swimmers: (1) increase torso muscle demands as swimming speed increases, (2) use the torso muscles to provide stability during lower limbs movements, and (3) challenge the torso muscles to maintain torso posture while moving the upper and lower limbs

THE APPLICATION OF FOURIER ANALYSIS TO DEMONSTRATE THE IMPACT OF THE FLUTTER KICK ON LONGITUDINAL ROTATION IN FRONT CRAWL

The contribution of the flutter kick to front crawl performance from its influence on longitudinal body rotation has not been thoroughly investigated. Fourier analysis was used to examine the impact of the kick on segmental and whole body angular momentum about the body’s longitudinal axis in fourteen elite front crawl specialists swimming at sprint and 400m pace. The third harmonic frequency, representing the effects of the six-beat flutter kick, was greater at sprint than 400m pace in lower limb, upper limb, and whole body angular momentum. The presence of the third harmonic in upper limb and whole body angular momentum indicates that the flutter kick has an influence on longitudinal body rotation. The role of the flutter kick in front crawl performance may be linked to actions of the torso muscles to help control longitudinal body rotation

\u3cem\u3eIn Vitro\u3c/em\u3e Determination of Potency of Small Molecule Inhibitors of Arp2/3 Complex

Actin is a key protein building block of actin microfilaments, which are constructed and deconstructed in response to cellular signaling pathways to regulate cellular processes such as motility, division, and endocytosis. Arp2/3 Complex is a 7-subunit protein complex that is in involved in cellular construction of branched actin networks, functioning by attaching to the side of a pre-existing actin filament and nucleating a daughter branch. Overexpression of Arp2/3 complex has been linked to the ability of certain metastatic cancers to proliferate. This work describes the synthesis and in vitro biochemical testing of several molecules predicted by computational docking to be inhibitors of Arp2/3 Complex, and therefore of potential interest in clinical applications. A bulk actin polymerization assay is used as the key method to determine the potency of inhibitor candidates. Structure-activity relationships derived from these results are also discussed

Analyzing polysemiosis: Language, gesture, and depiction in two cultural practices with sand drawing

Human communication is by default polysemiotic: it involves the spontaneous combination of two or more semiotic systems, the most important ones being language, gesture, and depiction. We formulate an original cognitive-semiotic framework for the analysis of polysemiosis, contrasting this with more familiar systems based on the ambiguous term “multimodality.” To be fully explicit, we developed a coding system for the analysis of polysemiotic utterances containing speech, gesture, and drawing, and implemented this in the ELAN video annotation software. We used this to analyze 23 video-recordings of sand drawing performances on Paama, Vanuatu and 20 sand stories of the Pitjantjatjara culture in Central Australia. Methodologically we used the conceptual-empirical loop of cognitive semiotics: our theoretical framework guided general considerations, such as distinguishing between the “tiers” of gesture and depiction, and the three kinds of semiotic grounds (iconic, indexical, symbolic), but the precise decisions on how to operationalize these were made only after extensive work with the material. We describe the coding system in detail and provide illustrative examples from the Paamese and Pitjantjatjara data, remarking on both similarities and differences in the polysemiosis of the two cultural practices. We conclude by summarizing the contributions of the study and point to some directions for future research

EXAMINING THE INTRA- AND INTER-DAY RELIABILITY OF THE VALD HUMANTRAK FOR RANGE OF MOTION OF THE SHOULDER IN FIXED- AND FREE-RANGE CONDITIONS

The purpose of this study was to assess the reliability of the VALD HumanTrak system for estimating shoulder range of motion in the sagittal and frontal planes. Intra- and inter-day reliability was assessed during fixed- and free-range shoulder movements. ICC ranged from good to excellent for abduction (0.753 - 0.959) and flexion (0.868 - 0.975) and poor to good for adduction (0.417 - 0.893) and extension (0.443 - 0.757). The VALD HumanTrak can be a reliable tool to estimate shoulder range of motion within the same day and across multiple days

Do the torso muscles produce torso twist in front crawl?

The purpose of this study was to investigate the association between torso muscle activity and torso twist. EMG data from five torso muscles and 3D motion capture data were recorded during 4x25m front crawl swimming trials at 400m and 50m pace (N=15). EMG data were integrated over 10ms intervals and normalized to the maximum value during each swimming trial (%iEMG) and torso twist acceleration was calculated as the second time derivative of the relative angle between thorax and pelvis about the longitudinal axis. Spearman correlations were calculated between 5th percentile scores of %iEMG and torso twist acceleration. Mean correlation coefficients were weak (i.e. r \u3c 0.30) for all muscles at both paces. The findings suggest that torso muscle activity may not be directly associated with torso twist acceleration

Panel 9 Playing Politics with Information Technology: A Global Perspective

[No abstract available

TRANSFERABILITY OF A PREVIOUSLY VALIDATED IMU SYSTEM FOR LOWER EXTREMITY KINEMATICS

This study tested transferability and validity of an Inertial Measurement Unit (IMU) system for estimation of lower limb kinematics. Peak hip, knee, and plantarflexion angles and sagittal plane range of motion (ROM) were compared during body weight squats (BWSQ) and countermovement jumps (CMJ) in 16 participants using root mean square error (RMSE) and intraclass correlation coefficients (ICC). RMSE wa