Fig. 6
From: Impaired contractile function of the supraspinatus in the acute period following a rotator cuff tear
Tenotomized supraspinatus becomes more susceptible to injury at 15D but not at 2D. The same apparatus used to collect isometric force (Fig. 2) was also used to induce injury. The suprascapular nerve is used to stimulate the supraspinatus maximally while movement of the lever arm resulted in forced linear lengthening of the muscle (15% Lo). a Representative screen shot showing force from a single eccentric contraction (closed arrow) superimposed onto a maximal isometric contraction (open arrow; y-axis in volts, which is converted to units of force based on calibration). b Representative rep-by-rep isometric force loss for one animal in each group throughout eccentric contraction protocol. c The mean loss of force for each group after the injury protocol. Despite an identical injury protocol, there is a greater drop in isometric force after injury at 15D (51.8 ± 2.5%) compared to control. All data are presented as mean ± SD, p < 0.05. *, indicates statistical significance compared to control