All patients will be encouraged to achieve the maximum time to task failure, stopped only by muscular fatigue or pain precluding to maintain the position. Each exercise will perform under two conditions.
On the control condition, the patients will perform both tests without any cognitive condition, while on the experimental condition they will be instructed to perform both tests while performing a mathematical subtracting task (starting at 300, by sevens).
The starting condition will be randomly assigned with a 5-minute rest prior to the next condition. Time to task failure and pain perception using a visual analog scale will be assessed.
