The effects of an 8 week supplemented plyometric exercise training program on leg power, agility and speed in adolescent netball players

Objectives: Agility, speed and power are important aspects of almost every sport. One way to improve these attributes is plyometric exercise training. Plyometrics have shown to be effective for improving performance in many sports such as basketball, volleyball, and AFL. The aim of this study was to determine the effects of an 8 week supplementary plyometric exercise training program on the physical performance of adolescent athletes in the sport of netball.\ud \ud Methods: Participants were randomly allocated to a control group (CG, n = 8) or an intervention group (IG, n = 8). All participants completed a battery of performance tests that included 10 m sprint, 505 agility, Illinois agility, vertical jump and 5 repetition one leg bounds. Both groups undertook the same netball training. The invention group also performed supplemental plyometric exercise training program over the 8 weeks training period. The plyometric exercises performed included: skipping, countermovement jumps, depth jumps and single leg bounds or alternate leg bounds. \ud \ud Results: Following the 8 weeks of training all participants were retested and the intervention group demonstrated significant improvements in 505 agility (4.02%) and 5 single leg bounds (6.69%). \ud Conclusions: It appears a supplemented plyometric exercise training program is of benefit to the adolescent netball player, for improving agility and power and it is recommended that this form of training be implemented into their normal training regime

Pollen and sperm heteromorphism: convergence across kingdoms ?

International audienceSperm competition theory predicts that males should produce many, similar sperm. However, in some species of animals and plants, males exhibit a heteromorphism that results in the production of at least two different types of sperm or pollen grains. In animals, sperm heteromorphism typically corresponds to the production of one fertile morph and one (or more) sterile morph(s), whereas in plants two or more pollen morphs (one of which can be either sterile or fertile) are produced in all flowers but sometimes in different anthers. Heteromorphism has arisen independently several times across phyla and at different phylogenetic levels. Here, we compare and contrast sperm and pollen heteromorphism and discuss the evolutionary hypotheses suggested to explain heteromorphism in these taxa. These hypotheses include facilitation, nutritive contribution, blocking, cheap filler, sperm flushing or killing for animals; outcrossing and precise cross-pollen transfer or bet-hedging strategy for plants; cryptic female choice for both. We conclude that heteromorphism in the two phyla is most likely linked to a general evolutionary response to sexual selection, either to increase one male's sperm or pollen success in competition with other males, or mediate male/female interactions. Therefore, although sperm and pollen are not homologous, we suggest that heteromorphism represents an example of convergence across kingdoms

Evaluation of surgical procedures for sex reassignment : a systematic review

Objectives: To evaluate earlier reviews and literature concerning five individual surgical procedures for male-to-female (MTF) transsexism: clitoroplasty, labiaplasty, orchidectomy, penectomy and vaginoplasty. Further evaluations were made of eight surgical procedures for female-to-male (FTM) transsexism: hysterectomy, mastectomy, metoidoplasty, phalloplasty, salpingo-oophorectomy, scrotoplasty/placement of testicular prostheses, urethroplasty and vaginectomy. Background: Increased prevalence and advances in surgical options available to patients requesting gender reassignment surgery have made this an important consideration for research. There remains a lack of systematic reviewing of the evidence, in particular, of the individual surgical options available. Methods: Searches were undertaken in six electronic databases (Applied Social Sciences Index and Abstracts [ASSIA], Cochrane Library [Wiley Online], Embase [Ovid Online], Medline [Ovid Online], Medline in Process [Ovid Online], Psycinfo) providing coverage of the biomedical, grey literature and current research. Results: Eighty-two published papers (38 MTF; 44 FTM) met the inclusion criteria identified across the 13 surgical procedures. For MTF transsexism there was no evidence satisfying the inclusion criteria concerning labiaplasty, penectomy or orchidectomy procedures. A large amount of evidence was available concerning vaginoplasty and clitoroplasty procedures. For FTM transsexism satisfactory outcomes were reported. Outcomes related to the ability to perform sexual intercourse, achieve orgasm and void whilst standing. Some complications were reported for both MTF and FTM procedures. Conclusions: The evidence concerning gender reassignment surgery in both MTF and FTM transsexism has several limitations in terms of: (a) lack of controlled studies, (b) evidence has not collected data prospectively, (c) high loss to follow up and (d) lack of validated assessment measures. Some satisfactory outcomes were reported, but the magnitude of benefit and harm for individual surgical procedures cannot be estimated accurately using the current available evidence