Influence of Ground Reaction Forces and Joint Velocities on Kicking Velocity

Introduction: Kicking is a vital component in the game of soccer. One major factor that influences the success of a scoring attempt is ball velocity. Ground reaction force (GRF) and joint velocities of the lower extremities are variables of interest for increasing kicking velocity. Previous studies have shown exercise programs used to strengthen the muscles used in kicking have been successful in increasing kicking velocity (Manolopoulos, et al., 2013).[GJR1] To date, no known studies have analyzed the specific relationship between GRF, joint velocity and kicking velocity. Purpose: The goal of this pilot study was to analyze the influence of ground reaction forces and joint velocities on kicking velocity. Methods: Four female Division II collegiate soccer players [GJR2] completed 3 instep soccer kicks [GJR3] using their dominant, right leg. Their motion was captured using the Cortex 8.1 Motion Analysis Software. Ball velocity, right and left anterior superior iliac spine (ASIS) and right and left ankle velocities were calculated using the motion analysis software. Ground reaction forces from the plant leg were also measured using force plate data from the Cortex software. Bivariate Pearson correlations with 0.95 confidence intervals were computed using SPSS version 28 for the resultant velocities of the right and left ASIS, right and left ankles, and the velocity of the ball. They were also calculated for the peak GRF in the anteroposterior (X), mediolateral (Y) and vertical (Z) directions and ball velocity. A correlation value of \u3e0.800 or \u3c -0.800 was considered significant. Results: Significant correlations were found between peak resultant ball velocity and GRF in the X direction (-0.907), GRF in the Y direction (0.867), R ASIS velocity (0.950), R ankle velocity (0.855), and L ankle velocity (0.977). No significant correlations were found between peak resultant ball velocity and GRF in the Z direction (0.788), or peak resultant ball velocity and peak joint velocity of the L ASIS (0.692). Conclusion: Braking force of the planting leg is shown to correlate significantly with kicking velocity. Although high braking force allows for a faster ball, this can have other implications to injury [GJR4] (Ball, 2012; Jones & Graham-Smith, 2016). Linear velocity of the hip also allows for greater ball velocity. As a pilot study, this study lacks the statistical power to extrapolate the information to larger populations. Therefore, additional studies are needed to further investigate the relationships between kicking mechanics and the resulting ball velocity

Correlation Between Quadriceps and Hamstring Isokinetic Strength to Ball Velocity During a Soccer Kick

When kicking a soccer ball, large forces are generated by the quadriceps and hamstring muscles that extend and flex the knee. The angular acceleration[GJR1] at this joint and the torques produced are[GJR2] related. PURPOSE: The goal of this pilot study was to explore the relationship between isokinetic strength[GJR3] of the quadriceps and hamstring muscles to velocity of a kicked soccer ball and determine if isokinetic testing of quadriceps and hamstring strength can predict soccer ball velocity during a kick. Methods: Four female NCAA Division II soccer athletes completed maximal effort knee flexion and extension at three isokinetic speeds, 60°/second, 180°/second, and 300°/second using the Biodex 3 Isokinetic Dynamometer. Cortex 8.1 Motion Analysis Software was used to record three maximal kicks with the dominant leg. Bivariate Pearson correlation coefficients were calculated between both data sets using SPSS version 28. Results: Ball velocity was significantly and positively correlated with Right Leg Flexion Acceleration time at 60°/second(r= 0.860),[GJR4] Left Leg Extension Acceleration at 180°/second (r= 0.950), and Left Leg Extension Acceleration at 300°/second (r= 0.915). Two significant negative relationships were discovered between ball velocity and left leg extension acceleration at 300°/second (r= -0.950), and left angle of peak extension torque at 300°/second (r= - 0.915). Conclusion: The ability to quickly accelerate the non-kicking leg to extension combined with the ability to reach angle of peak extension torque is associated with the ability to quickly stabilize the plant leg. Flexion of the kicking leg at a lower angular velocity corresponds with a higher force production and when combined with a positive correlation to ball velocity, suggests increased loading of the kicking leg prior to ball contact. Lastly, the negative correlation between ball velocity and kicking-leg extension acceleration would suggest that faster acceleration leads to increased ball velocity. Because of this, isokinetic testing of the quadricep and hamstring strength is likely a good predictor of kicking velocity. Further testing is required to determine if present correlations are applicable to other populations of soccer athletes, which can affect training and return-to-play practices

Conjunction and Disjunction in Infectious Logics

In this paper we discuss the extent to which conjunction and disjunction can be rightfully regarded as such, in the context of infectious logics. Infectious logics are peculiar many-valued logics whose underlying algebra has an absorbing or infectious element, which is assigned to a compound formula whenever it is assigned to one of its components. To discuss these matters, we review the philosophical motivations for infectious logics due to Bochvar, Halldén, Fitting, Ferguson and Beall, noticing that none of them discusses our main question. This is why we finally turn to the analysis of the truth-conditions for conjunction and disjunction in infectious logics, employing the framework of plurivalent logics, as discussed by Priest. In doing so, we arrive at the interesting conclusion that —in the context of infectious logics— conjunction is conjunction, whereas disjunction is not disjunction

Malignant melanoma of the rectum: a case report

<p>Abstract</p> <p>Introduction</p> <p>Anorectal melanoma represents an unusual but important presentation of rectal malignancy. There have only been a few cases reported and the optimum management for this condition is still undecided, however, prompt diagnosis is essential. We have outlined current treatment options.</p> <p>Case presentation</p> <p>We report a case of malignant melanoma of the rectum in a 55-year-old Caucasian man presenting as an emergency with rectal bleeding. Biopsies were taken of the fleshy mass found on digital examination, which confirmed malignant melanoma. No distant metastases were found. He underwent an abdominoperineal resection. We report the surgical management of this rare and aggressive malignancy.</p> <p>Conclusion</p> <p>Treatment options for this condition are divergent. Surgical management varies from wide local excision to abdominoperineal resection. Clinical awareness in both medical and surgical clinics is required for prompt diagnosis and treatment.</p

The Iowa Homemaker vol.21, no.1

Fabric Personality, Editor, page 1 The Fate of Textiles, Ann Koebel, page 2 In a War Torn World, Betty Ann Brady, page 3 Sizes Turn to Tapelines, Gertrude Dieken, page 4 Wardrobe with a Plan, page 5 Sally Finds Fashion, Ida Halpin, page 6 Flower Etiquette, Doris Plagge, page 7 Enriched Flour, Clara Gebhard Snyder, page 8 Textiles and Clothing Department, Margaret Read, page 9 What’s New in Home Economics, page 10 Behind Bright Jackets, Marjorie Thomas, page 14 The Homemaker Celebrates, Mrs. Fred E. Ferguson, page 15 Home Economics and Kitty Foyle, Allan Beegle, page 16 Journalistic Spindles, Patricia Craven, page 17 Alums in the News, Bette Simpson, page 1

Plasmodium SAS4: basal body component of male cell which is dispensable for parasite transmission.

The centriole/basal body (CBB) is an evolutionarily conserved organelle acting as a microtubule organising centre (MTOC) to nucleate cilia, flagella, and the centrosome. SAS4/CPAP is a conserved component associated with BB biogenesis in many model flagellated cells. Plasmodium, a divergent unicellular eukaryote and causative agent of malaria, displays an atypical, closed mitosis with an MTOC (or centriolar plaque), reminiscent of an acentriolar MTOC, embedded in the nuclear membrane. Mitosis during male gamete formation is accompanied by flagella formation. There are two MTOCs in male gametocytes: the acentriolar nuclear envelope MTOC for the mitotic spindle and an outer centriolar MTOC (the basal body) that organises flagella assembly in the cytoplasm. We show the coordinated location, association and assembly of SAS4 with the BB component, kinesin-8B, but no association with the kinetochore protein, NDC80, indicating that SAS4 is part of the BB and outer centriolar MTOC in the cytoplasm. Deletion of the SAS4 gene produced no phenotype, indicating that it is not essential for either male gamete formation or parasite transmission

Plasmodium SAS4: basal body component of male cell which is dispensable for parasite transmission

The centriole/basal body (CBB) is an evolutionarily conserved organelle acting as a microtubule organising centre (MTOC) to nucleate cilia, flagella, and the centrosome. SAS4/CPAP is a conserved component associated with BB biogenesis in many model flagellated cells. Plasmodium, a divergent unicellular eukaryote and causative agent of malaria, displays an atypical, closed mitosis with an MTOC (or centriolar plaque), reminiscent of an acentriolar MTOC, embedded in the nuclear membrane. Mitosis during male gamete formation is accompanied by flagella formation. There are two MTOCs in male gametocytes: the acentriolar nuclear envelope MTOC for the mitotic spindle and an outer centriolar MTOC (the basal body) that organises flagella assembly in the cytoplasm. We show the coordinated location, association and assembly of SAS4 with the BB component, kinesin8B, but no association with the kinetochore protein, NDC80, indicating that SAS4 is part of the BB and outer centriolar MTOC in the cytoplasm. Deletion of the SAS4 gene produced no phenotype, indicating that it is not essential for either male gamete formation or parasite transmission

Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei

Plasmodium P-type cyclin CYC3 modulates endomitotic growth during oocyst development in mosquitoes

Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei

Plasmodium NEK1 coordinates MTOC organisation and kinetochore attachment during rapid mitosis in male gamete formation

Mitosis is an important process in the cell cycle required for cells to divide. Never in mitosis (NIMA)-like kinases (NEKs) are regulators of mitotic functions in diverse organisms. Plasmodium spp., the causative agent of malaria is a divergent unicellular haploid eukaryote with some unusual features in terms of its mitotic and nuclear division cycle that presumably facilitate proliferation in varied environments. For example, during the sexual stage of male gametogenesis that occurs within the mosquito host, an atypical rapid closed endomitosis is observed. Three rounds of genome replication from 1N to 8N and successive cycles of multiple spindle formation and chromosome segregation occur within 8 min followed by karyokinesis to generate haploid gametes. Our previous Plasmodium berghei kinome screen identified 4 Nek genes, of which 2, NEK2 and NEK4, are required for meiosis. NEK1 is likely to be essential for mitosis in asexual blood stage schizogony in the vertebrate host, but its function during male gametogenesis is unknown. Here, we study NEK1 location and function, using live cell imaging, ultrastructure expansion microscopy (U-ExM), and electron microscopy, together with conditional gene knockdown and proteomic approaches. We report spatiotemporal NEK1 location in real-time, coordinated with microtubule organising centre (MTOC) dynamics during the unusual mitoses at various stages of the Plasmodium spp. life cycle. Knockdown studies reveal NEK1 to be an essential component of the MTOC in male cell differentiation, associated with rapid mitosis, spindle formation, and kinetochore attachment. These data suggest that P. berghei NEK1 kinase is an important component of MTOC organisation and essential regulator of chromosome segregation during male gamete formation