Parasitic isopods of Bopyroidea and Cryptoniscoidea (commonly referred to as epicarideans) are unique in using crustaceans as both intermediate and definitive hosts. In total, 795 epicarideans are known, representing ∼7.7% of described isopods. The rate of description of parasitic species has not matched that of free-living isopods and this disparity will likely continue due to the more cryptic nature of these parasites. Distribution patterns of epicarideans are influenced by a combination of their definitive (both benthic and pelagic species) and intermediate (pelagic copepod) host distributions, although host specificity is poorly known for most species. Among epicarideans, nearly all species in Bopyroidea are ectoparasitic on decapod hosts. Bopyrids are the most diverse taxon (605 species), with their highest diversity in the North West Pacific (139 species), East Asian Sea (120 species), and Central Indian Ocean (44 species). The diversity patterns of Cryptoniscoidea (99 species, endoparasites of a diverse assemblage of crustacean hosts) are distinct from bopyrids, with the greatest diversity of cryptoniscoids in the North East Atlantic (18 species) followed by the Antarctic, Mediterranean, and Arctic regions (13, 12, and 8 species, respectively). Dajidae (54 species, ectoparasites of shrimp, mysids, and euphausids) exhibits highest diversity in the Antarctic (7 species) with 14 species in the Arctic and North East Atlantic regions combined. Entoniscidae (37 species, endoparasites within anomuran, brachyuran and shrimp hosts) show highest diversity in the North West Pacific (10 species) and North East Atlantic (8 species). Most epicarideans are known from relatively shallow waters, although some bopyrids are known from depths below 4000 m. Lack of parasitic groups in certain geographic areas is likely a sampling artifact and we predict that the Central Indian Ocean and East Asian Sea (in particular, the Indo-Malay-Philippines Archipelago) hold a wealth of undescribed species, reflecting our knowledge of host diversity patterns.
The purpose of this study was to examine the concurrent validity of 4 clinical tests used to measure hamstring muscle length. A pilot study (N = 10) was conducted to determine the intratester reliability of 4 hamstring length measures: knee extension angle (KEA), sacral angle (SA), straight leg raise (SLR), and sit and reach (SR). The pilot investigation revealed good to excellent intratester reliability (intraclass correlation coefficient = 0.92-0.95) for each of the 4 tests. Eighty-one subjects (42 men and 39 women) participated in the main investigation. Subjects were randomly tested for each of 4 assessments of hamstring length. Concurrent validity was determined using linear regression, correlation, and kappa statistics. Correlation coefficients corresponding to the concurrent validity of the six combinations of the 4 clinical tests revealed poor to fair correlation (r = 0.45-0.65). The correlation coefficients for each pair from greatest to least were SR-SA= 0.65, SLR-SR = 0.65, KEA-SLR = 0.63, KEA-SR = 0.57, SLR-SA = 0.50, and KEA-SA = 0.45. Despite the common clinical use of these measures to assess hamstring length, these tests do not have sufficient concurrent validity to be used interchangeably or to assume that they each measure the same construct (hamstring length). Based on the results of this investigation and a review of the literature, the authors recommend that researchers, clinicians, and strength and conditioning specialists adopt the KEA test as the gold standard measure for hamstring muscle length.
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