The Pearl : La Perla

https://digitalcommons.library.umaine.edu/mmb-vp/4928/thumbnail.jp

INTER-LIMB COORDINATION DURING SPRINT ACCELERATION

Bilateral coordination is inherent to running motions but has not been investigated during sprint acceleration. The purpose of the study was to examine inter-limb thigh coordination during the first four steps of sprint acceleration in elite and sub-elite athletes. Anti-phase coordination patterns predominated in each step, but the proportion of anti-phase motion was higher in elite athletes (85.9 ± 10.8%) than sub-elite athletes (76.8 ± 10.9%, ES 0.83). Coordination profiles suggest that sub-elite athletes exhibit longer periods of the trailing (+) pattern around the time of touchdown (swing thigh flexing, stance thigh fixed) and the leading (-) pattern in the latter part of stance (stance thigh extending, swing thigh fixed) compared with elite athletes. These results provide preliminary empirical support for the emphasis placed on the switching of the limbs by coaches

WITHIN-SUBJECT REPEATABILITY AND BETWEEN-SUBJECT VARIABILITY IN POSTURE DURING CALIBRATION OF AN INERTIAL MEASUREMENT UNIT SYSTEM

Inertial measurement units (IMUs) are a valuable tool for field based sports research, but within- and between-subject comparisons may be affected by variation in the 0° position established by a standing calibration position. This study assessed within-subject repeatability and between-subject variability in IMU sensor orientations during calibration. Calibration posture was reliable within-subjects given standardised instructions (typical error \u3c 1.9°). Sensor angles relative to a global vertical axis had large between-subject ranges for upper spine (21–35°), lower spine (1–23°) and pelvis (11–35°), while lower limb segment angles had much lower variability (0-6°). Thus, a standing calibration posture is repeatable within participants given suitable instructions, however variability in standing posture may need to be accounted for before making between-subject comparisons, particularly with regard to spine and pelvis segments

SIMILARITY OF COORDINATION PATTERNS IN A GROUP OF HIGHLY TRAINED SPRINTERS: A NOVEL APPROACH

Understanding coordination patterns aids technical understanding and potential grouping of athletes that exhibit similar movement patterns. This study assessed between-individual similarity in initial sprint acceleration coordination in highly trained to world class sprinters using a novel pairwise approach. Similarity between participants was higher for thigh-thigh coordination compared to shank-foot and trunk-shank coordination. Mean similarity increased from step 1 to step 4 in shank-foot (0.74 to 0.83) and trunk-shank (0.68 to 0.79) couplings but remained consistent in the thigh-thigh coupling (0.89 to 0.91). Researchers and practitioners should consider that coordination between sprinters converges over initial acceleration, but between any two individuals coordination similarity might increase or decrease across steps

A COMPARISON OF TRUNK AND SHANK ANGLES BETWEEN ELITE AND SUB-ELITE SPRINTERS DURING SPRINT ACCELERATION

Acceleration is a movement that requires skilful positioning of the body to apply force in the desired direction. The sagittal plane orientation of the trunk and shank are features that coaches use to visually assess sprint acceleration technique. This study examined differences in trunk and shank angles between elite and sub-elite sprinters during early acceleration using inertial sensors. Elite sprinters exhibited more vertical trunk positions throughout all four steps compared to sub-elite with moderate to very large differences at discrete events (d = 0.79 - 2.16). Shank angles were more vertical at touchdown in sub-elite compared to elite sprinters (d = -0.70 - -0.39), but similar at toe-off. These results suggest that less horizontal trunk lean during acceleration is a feature of higher level sprinters, coaches should be conscious of this when giving technical feedback

Inter- and intra-limb coordination during initial sprint acceleration

In complex movements, centre of mass translation is achieved through effective joint and segment rotations. Understanding segment organisation and coordination is therefore paramount to understanding technique. This study sought to comprehensively describe inter- and intra-limb coordination and assess step-to-step changes and between-individual variation in coordination during initial sprint acceleration. Twenty-one highly trained to world class male (100 m PB 9.89-11.15 s) and female (100 m PB:11.46-12.14 s) sprinters completed sprint trials of at least 20 m from which sagittal plane kinematics were obtained for the first four steps using inertial measurement units (200 Hz). Thigh-thigh, trunk-shank and shankfoot coordination was assessed using a modified vector coding and segment dominancy approach. Common coordination patterns emerged for all segment couplings across sexes and performance levels, suggesting strong task constraints. Between-individual variation in inter-limb thigh coordination was highest in early flight, while trunk-shank and shank-foot variation was highest in late flight, with a second peak in late stance for the trunk-shank coupling. There were clear step-to-step changes in coordination, with step 1 being distinctly different to subsequent steps. The results demonstrate that inter-limb coordination is primarily anti-phase and trailing leg dominant while ankle motion in flight and late stance appears to be primarily driven by the foot.Open Access funding provided by University of Pretoria.http://bio.biologists.orgam2023PhysiologySports Medicin

Step-to-step changes in foot-shank coordination during initial sprint acceleration

https://drive.google.com/file/d/1ynthZ4BT5pxixTimBAnkOFjiK24w54xW/view?usp=sharinghttps://drive.google.com/drive/folders/1Co2AgE1AfDQOhLPhoRiW7pTM362tNQIR?usp=sharinghttps://drive.google.com/drive/folders/1-Ke_TyNZoPBz-1uzNrMDJ4PggLvuO_eQ?usp=sharin

Pro-tobacco marketing and anti-tobacco campaigns aimed at vulnerable populations: A review of the literature.

INTRODUCTION:We reviewed research literature on pro-tobacco marketing and anti-tobacco campaigns targeting eight vulnerable populations to determine key findings and research gaps. Results can inform tobacco policy and control efforts and the design of public education campaigns for these groups. METHODS:Five journal databases in medicine, communication, and science, were used to identify 8875 peer-reviewed, original articles in English, published in the period 2004-2018. There were 144 articles that met inclusion criteria on pro-tobacco marketing or anti-tobacco campaigns aimed at eight US groups: women of reproductive age, racial/ethnic minority groups (African American, Hispanic/Latino, Asian/Pacific Islander and American Indian/Alaska Native), Lesbian/Gay/Bisexual/Transgender (LGBT) populations, groups with low socioeconomic status, rural/inner city residents, military/veterans, and people with mental health or medical co-morbidities. We summarized the number of articles for each population, type of tobacco, and pro-tobacco or anti-tobacco focus. Narrative summaries were organized by population and by pro-tobacco or anti-tobacco focus, with key strategies and gaps by group. RESULTS:There were more studies on pro-tobacco marketing rather than anti-tobacco campaigns, and on cigarettes rather than other tobacco products. Major gaps included studies on Asian Americans, American Indian/Alaska Natives, pregnant women, LGBT populations, and those with mental health or medical co-morbidities. Gaps related to tobacco products were found for hookah, snus, and pipe/roll-your-own tobacco in the pro-tobacco studies, and for all products except cigarettes in anti-tobacco studies. Common tobacco industry methods used were tailoring of product and package design and messages that were used to reach and appeal to different sociodemographic groups. Studies varied by research design making it difficult to compare results. CONCLUSIONS:We found major research gaps for specific groups and tobacco products. Public education campaigns need a stronger foundation in empirical studies focused on these populations. Research and practice would benefit from studies that permit comparisons across studies

Assessment of numerical procedures for determining shallow foundation failure envelopes

The failure envelope approach is commonly used to assess the capacity of shallow foundations under combined loading, but there is limited published work that compares the performance of various numerical procedures for determining failure envelopes. This paper addresses this issue by carrying out a detailed numerical study to evaluate the accuracy, computational efficiency and resolution of these numerical procedures. The procedures evaluated are the displacement probe test, the load probe test, the swipe test (referred to in this paper as the single swipe test) and a less widely used procedure called the sequential swipe test. Each procedure is used to determine failure envelopes for a circular surface foundation and a circular suction caisson foundation under planar vertical, horizontal and moment (VHM) loading for a linear elastic, perfectly plastic von Mises soil. The calculations use conventional, incremental-iterative finite-element analysis (FEA) except for the load probe tests, which are performed using finite-element limit analysis (FELA). The results demonstrate that the procedures are similarly accurate, except for the single swipe test, which gives a load path that under-predicts the failure envelope in many of the examples considered. For determining a complete VHM failure envelope, the FEA-based sequential swipe test is shown to be more efficient and to provide better resolution than the displacement probe test, while the FELA-based load probe test is found to offer a good balance of efficiency and accuracy

What about the men? Northern men’s research project final report

https://www.nwtliteracy.ca/sites/default/files/research/nmrp_final_report_2015_0.pd