Is recovery from muscle damage retarded by a subsequent bout of eccentric exercise inducing larger decreases in force?
The aim of this study was to investigate whether a subsequent bout of eccentric exercise inducing larger decreases in force than the initial bout would exacerbate muscle damage and retard recovery. Changes in indirect markers of muscle damage were measured over 14 days when 24 maximal eccentric actions of the elbow flexors were performed on days 1 (ECC1) and 7 (ECC2], with electrical stimulation superimposed percutaneously to the elbow flexors during maximal eccentric actions in ECC2. Maximal isometric force (MIF), range of motion (ROM), upper arm circumference, muscle soreness, B-mode ultrasound, and several muscle proteins in the blood were assessed before, immediately after and for 5 days after both bouts. Magnetic resonance Imaging (MRI) was assessed 4 days after both bouts. MIF decreased to 45% of the pre-exercise value immediately after ECC 1 and recovered to 59% by day 7 post-exercise. MIF decreased to 22% of pre-ECC1 value immediately after ECC2, but recovered to 105% of pre-EC
