Eccentric exercise of the quadriceps femoris muscle was performed between 40[degrees] and 110[degrees] of knee flexion (0[degrees] = full extension), at an angular velocity of 5[degrees]/s.
Between the 21st and 30th days after eccentric exercise, two subjects still showed an increase in the signal for all parts of the quadriceps femoris muscle (Figure 5 and Table 1).
This study assessed the time course of functional recovery of the quadriceps femoris muscle after injury induced by eccentric exercise at low angular speed.
An increase in intensity of the MRI signal was shown for all parts of the quadriceps femoris muscle on the 2nd and 7th days after eccentric exercise, which remained high between the 21st and 30th days in two subjects.
However, these authors found no difference in the MDF of the quadriceps femoris muscle (vastus medialis and vastus lateralis), suggesting that the speed does not alter the motor unit recruitment pattern (no selective recruitment) during isokinetic exercise.
The majority of studies that evaluated the CK level used maximal eccentric contraction or even downhill running, where sub-maximal eccentric contraction of the quadriceps femoris muscle occurs.
The quadriceps femoris muscle injured by eccentric exercise, already started its functional recovery, as demonstrated by the behaviour of MVC torque and electrical activity, in the first week after eccentric exercise, despite the presence of an increase in the intensity of the MRI signal;