A Cumulative Stress and Training Continuum Model: A Multidisciplinary Approach to Unexplained Underperformance Syndrome

This article provides an understanding of the unexplained underperformance syndrome (UPS; Budgett, Newsholme, Lehmann, et al. 19994. Budgett, R, Newsholme, E, Lehmann, M, Sharp, C, Jones, D, Peto, T, Collins, D, Nerurkar, R and White, P. 1999. Redefining the overtraining syndrome as the unexplained underperformance syndrome. British Journal of Sports Medicine, 34: 67–68. View all references) and the problems surrounding the current presentation of it. This was done in terms of processes and outcomes. Recommendations for a more stringent usage of terms was provided. Based on Selye’s (1956)27. Selye, H. 1956. The Stress of Life, New York: McGraw-Hill. View all references General Adaptation Theory and a model described by Kenttä and Hassmén (199816. Kenttä, G and Hassmén, P. 1998. Overtraining and recovery—a conceptual model. Sports Medicine, 26: 1–26. View all references; 200217. Kereszty, A. 1971. “Overtraining”. In Encyclopaedia of Sports Sciences and Medicine, Edited by: Larson, LA and Herrmann, DE. 218–222. New York: Macmillan. View all references), a Cumulative Stress and Training Continuum Model was put forward that incorporates both the continuum paradigm and the supercompensation cycle model of training. These models, combined with a multidisciplinary approach, provide a useful framework for understanding the processes and outcomes of athletic performance in general and the unexplained underperformance syndrome in particular. The Cumulative Stress and Training Continuum Model emphasizes the complex interactions between the many factors affecting UPS and their weblike, cumulative, and synergistic relationships. Such an approach assists in explaining how seemingly nonsignificant factors in their own right could exert disproportionate importance and effect. Also, it emphasizes the individual variability and susceptibility to UPS as well as the fluctuations within a given individual. The unique contribution of the Cumulative Stress and Training Continuum Model put forward in the present article is that it is a truly inclusive and holistic model for addressing UPS

A question of homology for chordate adhesive organs

The larvae of aquatic vertebrates sometimes possess a transient, mucus-secreting gland on their heads. The most studied of these organs is the Xenopus cement gland. The tadpoles use it to attach to plants or to the water surface, supposedly to hide from predators and save energy before they can swim or feed. Moreover their gland, being innervated by trigeminal fibres, also mediates a locomotor stopping response when the larvae encounter an obstacle. We have described an equivalent organ on the head of the teleost Astyanax mexicanus, that we have called the casquette because of its shape and position on the larval head. The casquette is transient, sticky, secretes mucus, is innervated by the trigeminal ganglion, has an inhibitory function on larval swimming behavior, and expresses Bmp4 and Pitx1/2 during embryogenesis. Here we further discuss the nature of the equivalence between the frog cement gland and the fish casquette, and highlight the usefulness of non-conventional model species to decipher developmental and evolutionary mechanisms of morphological variations