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Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,111
Vivian M. ARAKELIAN 1, 2, Renata G. MENDES 1, Renata TRIMER 1, Flávia C. ROSSI CARUSO 1, Nuno M. DE SOUSA 3, Vanessa C. BORGES 3, Camila DO VALLE GOMES GATTO 3, Vilmar BALDISSERA 3, Ross ARENA 4, Audrey BORGHI-SILVA 1, 2
1 Cardiopulmonary Physiotherapy Laboratory, Department of Physiotherapy, Federal University of Sao Carlos, Sao Carlos, SP, Brazil; 2 Programa de Pós-graduação Interunidades em Bioengenharia - EESC / FMRP / IQSC, University of São Paulo, USP, Sao Carlos, SP, Brazil; 3 Laboratory of Exercise Physiology, Department of Physiological Science, Federal University of Sao Carlos, UFSCar, Sao Carlos, SP, Brazil; 4 Department of Physical Therapy and Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinios Chicago, Chicago, IL, USA
BACKGROUND: A hyperbolic function as well as a linear relationship between power output and time to exhaustion (Tlim) has been consistently observed during dynamic non-resistive exercises. However, little is known about its concept to resistance exercises (RE), which could be defined as critical load (CL). This study aimed to verify the existence of CL during dynamic RE and to verify the number of workbouts necessary to determine the optimal modeling to achieve it.
METHODS: Fifteen healthy men (23±2.5 ys) completed 1 repetition maximum test (1RM) on a Leg press and 3 (60, 75 and 90% of 1RM) or 4 (+ 30% of 1RM) workbouts protocols to obtain the CL by hyperbolic and linear regression models between Tlim and load performed. Blood lactate and leg fatigue were also measured.
RESULTS: CL was obtained during RE and 3 workbouts protocol estimate it at 53% while 4 tests at 38% of 1 RM. However, based on coefficients of determination, 3 protocols provided a better fit than the 4- parameter model, respectively (R2>.95 vs >.77). Moreover, all intensities increased blood lactate and leg fatigue, however, when corrected by Tlim, were significantly lower at CL.
CONCLUSION: It was possible to determinate CL during dynamic lower limbs RE and that 3 exhaustive workbouts can be used to better estimate the CL, constituting a new concept of determining this threshold during dynamic RE and reducing the physically demanding nature of the protocol. These findings may have important applications for functional performance evaluation and prescription of RE programs.