Critical power as a measure of physical work capacity and anaerobic thresholdAbstract Monod and Scherrer (1965) showed that there was a linear relation between the maximal work and the maximal time over which the work was performed until the onset of local muscular exhaustion. This linear relation could be expressed by the equation: W lim =a+bT lim, where maximal work (Wlim) was thought to result from the use of an energy reserve (a) and an energy reconstitution whose maximal rate was (b) We have extended this concept to total body work (bicycle ergometer). Eight male and eight female college students underwent exercise tests at 400, 350, 300,275 and 300,250,200,175 W respectively, to the onset of fatigue. The regression analysis revealed that the linearity of individual plots was found to be 0-982<R 2<0 998 (p<0 01). Experimental results indicated that the maximal energy reconstitution rate (b) was correlated with the onset of anaerobic threshold (AT) as determined by the gas exchange method (r = 0 928, p <0 01). Furthermore, the sum of (a) and (b) (energy reserve and maximal rate of energy reconstitution) was found to be highly correlated with [Vdot]O2 max (r = 0 956, p < 0001) and the regression equation: [Vdot]O2max (1/min) = 0 00795 x [a + b] + 0 114 could be used to predict [Vdot]O2max with a SEE of 0-241/min. Additional informationNotes on contributorsTOSHIO MORITANI Present address: Bio-dynamics Laboratory, Department of Physical Education, University of Texas at Arlington, U.S.A.
Cytotoxic Lesions of the Corpus Callosum That Show Restricted Diffusion: Mechanisms, Causes, and ManifestationsCytotoxic lesions of the corpus callosum (CLOCCs) are secondary lesions associated with various entities. CLOCCs have been found in association with drug therapy, malignancy, infection, subarachnoid hemorrhage, metabolic disorders, trauma, and other entities. In all of these conditions, cell-cytokine interactions lead to markedly increased levels of cytokines and extracellular glutamate. Ultimately, this cascade can lead to dysfunction of the callosal neurons and microglia. Cytotoxic edema develops as water becomes trapped in these cells. On diffusion-weighted magnetic resonance (MR) images, CLOCCs manifest as areas of low diffusion. CLOCCs lack enhancement on contrast material–enhanced images, tend to be midline, and are relatively symmetric. The involvement of the corpus callosum typically shows one of three patterns: (a) a small round or oval lesion located in the center of the splenium, (b) a lesion centered in the splenium but extending through the callosal fibers laterally into the adjacent white matter, or (c) a lesion centered posteriorly but extending into the anterior corpus callosum. CLOCCs are frequently but not invariably reversible. Their pathologic mechanisms are discussed, the typical MR imaging findings are described, and typical cases of CLOCCs are presented. Although CLOCCs are nonspecific with regard to the underlying cause, additional imaging findings and the clinical findings can aid in making a specific diagnosis. Radiologists should be familiar with the imaging appearance of CLOCCs to avoid a misdiagnosis of ischemia. When CLOCCs are found, the underlying cause of the lesion should be sought and addressed. ©RSNA, 2017 An earlier incorrect version of this article appeared online. This article was corrected on February 13, 2017.
Motor unit activity and surface electromyogram power spectrum during increasing force of contractionToshio Moritani, Masuo Muro|European Journal of Applied Physiology|1987 Spontaneous regression of localized neuroblastoma detected by mass screening.Keiko Yamamoto, Ryoji Hanada, Akira Kikuchi et al.|Journal of Clinical Oncology|1998 PURPOSE: To clarify whether and when neuroblastomas identified through screening do regress, and to ascertain how to treat them appropriately, we observed screened patients who had localized tumors, without any therapeutic intervention. PATIENTS AND METHODS: The criteria for the observation program were as follows: disease stage I or II; tumor less than 5 cm in diameter; no invasion to the intraspinal canal or growth to the great vessels; urinary vanillylmandelic acid (VMA) and homovanillic acid (HVA) less than 50 microg/mg creatinine; and informed consent. Of 25 patients identified through screening for 6-month-old infants in Saitama Prefecture, Japan between April 1994 and March 1996, 11 patients who met the criteria and one other patient with stage III tumor were enrolled onto the program. They were examined by abdominal ultrasonography (US) and their urinary VMA and HVA levels were assessed approximately once per month. The observation periods ranged from 4 to 27 months. RESULTS: The 11 tumors decreased in size, although one of these 11 tumors initially enlarged until the patient was 12 months of age and decreased in size thereafter. One other tumor slightly increased in size. Urinary VMA levels decreased in all patients. None of the tumors had completely disappeared by the last observation day. CONCLUSION: Our results suggest that regression of screened neuroblastoma is not a rare phenomenon. At present, it seems reasonable to adopt a wait-and-see strategy, with careful observation, for selected stage I or II tumors identified in infants screened at 6 months of age.
Assessment of lower-back muscle fatigue using electromyography, mechanomyography, and near-infrared spectroscopyYasuhide Yoshitake, Hidetoshi Ue, M. Miyazaki et al.|European Journal of Applied Physiology|2001