Tetanic contractions: To ensure attainment of plateau level of contractions torque values were calculated as the mean of the last second of the 3-s contraction. Peak tetanic torque values were the highest obtained value. The tetanic stimulation period was subdivided into five intervals where interval 1 corresponds to the first 60 seconds (1-15 contractions), interval 2 from 61-120 seconds (16-30 contractions), interval 3 from 121-160 seconds (31-40 contractions), interval 4 the first 120 seconds (1-30 contractions) and interval 5 to the total period of 160 seconds (1-40 contractions). For each interval the resistance to muscle fatigue was expressed as a Fatigue Index (FI) and calculated as the ratio between the sum of peak torque values from the final three contractions relative to the sum of peak torque values from the first three contractions. Furthermore were peak torque values for each contraction plotted and the slope of the regression line for each interval calculated.