Purpose: To determine if the mathematical model used for the estimation of critical force (CF) and the energy store component W′ are applicable to intermittent isometric muscle actions of the finger flexors of rock climbers, using a multisession test. As a secondary aim, the agreement of estimates of CF and W′ from a single-session test was also determined. The CF was defined as the slope coefficient, and W′ was the intercept of the linear relationship between total “isometric work” (W lim) and time to exhaustion (T lim). Methods: Subjects performed 3 (separated by either 20 min or >24 h) tests to failure using intermittent isometric finger-flexor contractions at 45%, 60%, and 80% of their maximum voluntary contraction. Results: Force plotted against T lim displayed a hyperbolic relationship; correlation coefficients of the parameter estimates from the work–time CF model were consistently very high (R 2 > .94). Climbers’ mean CF was 425.7 (82.8) N (41.0% [6.2%] maximum voluntary contraction) and W′ was 30,882 (11,820) N·s. Good agreement was found between the single-session and multisession protocol for CF (intraclass correlation coefficient [ICC3,1] = .900; 95% confidence interval, .616–.979), but not for W′ (ICC3,1 = .768; 95% confidence interval, .190–.949). Conclusions: The results demonstrated the sensitivity of a simple test for the determination of CF and W′, using equipment readily available in most climbing gyms. Although further work is still necessary, the test of CF described is of value for understanding exercise tolerance and to determine optimal training prescription to monitor improvements in the performance of the finger flexors.
David Giles, Joel B. Chidley, Nicola Taylor, Ollie Torr, Josh Hadley, Tom Randall and Simon Fryer
Salomé Aubert, Joel D. Barnes, Chalchisa Abdeta, Patrick Abi Nader, Ade F. Adeniyi, Nicolas Aguilar-Farias, Dolores S. Andrade Tenesaca, Jasmin Bhawra, Javier Brazo-Sayavera, Greet Cardon, Chen-Kang Chang, Christine Delisle Nyström, Yolanda Demetriou, Catherine E. Draper, Lowri Edwards, Arunas Emeljanovas, Aleš Gába, Karla I. Galaviz, Silvia A. González, Marianella Herrera-Cuenca, Wendy Y. Huang, Izzeldin A.E. Ibrahim, Jaak Jürimäe, Katariina Kämppi, Tarun R. Katapally, Piyawat Katewongsa, Peter T. Katzmarzyk, Asaduzzaman Khan, Agata Korcz, Yeon Soo Kim, Estelle Lambert, Eun-Young Lee, Marie Löf, Tom Loney, Juan López-Taylor, Yang Liu, Daga Makaza, Taru Manyanga, Bilyana Mileva, Shawnda A. Morrison, Jorge Mota, Vida K. Nyawornota, Reginald Ocansey, John J. Reilly, Blanca Roman-Viñas, Diego Augusto Santos Silva, Pairoj Saonuam, John Scriven, Jan Seghers, Natasha Schranz, Thomas Skovgaard, Melody Smith, Martyn Standage, Gregor Starc, Gareth Stratton, Narayan Subedi, Tim Takken, Tuija Tammelin, Chiaki Tanaka, David Thivel, Dawn Tladi, Richard Tyler, Riaz Uddin, Alun Williams, Stephen H.S. Wong, Ching-Lin Wu, Paweł Zembura and Mark S. Tremblay
Background: Accumulating sufficient moderate to vigorous physical activity is recognized as a key determinant of physical, physiological, developmental, mental, cognitive, and social health among children and youth (aged 5–17 y). The Global Matrix 3.0 of Report Card grades on physical activity was developed to achieve a better understanding of the global variation in child and youth physical activity and associated supports. Methods: Work groups from 49 countries followed harmonized procedures to develop their Report Cards by grading 10 common indicators using the best available data. The participating countries were divided into 3 categories using the United Nations’ human development index (HDI) classification (low or medium, high, and very high HDI). Results: A total of 490 grades, including 369 letter grades and 121 incomplete grades, were assigned by the 49 work groups. Overall, an average grade of “C-,” “D+,” and “C-” was obtained for the low and medium HDI countries, high HDI countries, and very high HDI countries, respectively. Conclusions: The present study provides rich new evidence showing that the situation regarding the physical activity of children and youth is a concern worldwide. Strategic public investments to implement effective interventions to increase physical activity opportunities are needed.