The aim of the study is comparison of the effects of soft tissue manipulation and rest on the knee extensor muscle fatigue after maximal isokinetic contractions.
Fifteen healthy females aged 20-30 years selected for research. This study implemented a semi-experimental test-retest measurement method. Each of the volunteers was evaluated three sessions. The first session was to familiarize the volunteers with the test and isokinetics. For the main test, each of the volunteers was evaluated twice with a one-week interval between evaluations. In each session, after warm-up, perceived fatigue using a visual analog scale (VAS), average of peak torque (APT), and average power (AP) for maximal concentric isokinetic output of the quadriceps was measured at a velocity of 60 degrees per second. Then¸ in order to apply the fatigue protocol, the subjects were asked to perform successive maximal quadriceps contractions until three consecutive quadriceps torque outputs reached below 50 percent maximal torque output. Afterwards, for remeasurement, the average of peak torque and average power were calculated. The extent of perceived fatigue was evaluated as before. Subjects then either rested or received soft tissue manipulation on the knee extensors for a 15-minute duration. After intervention (soft tissue manipulation or rest) parameters were evaluated for third time.
The stability of average peak torque¸ average power, and visual analog scale before performing fatigue protocol was 85%, 83%, and 31.9%, respectively. The stability after fatigue was 43%, 50%, and 93%, respectively. After maximal fatigue and a decrease in torque output to below 50 percent maximal torque, 15 minutes of soft tissue manipulation could change the APT after fatigue from a mean of 58.3 (nm) to 91.5 (nm), the AP from 39.4 to 63.6 (nm/s), and the VAS from 90.0 to 12 (mm). But 15 minutes of rest could change the APT from 52.5 to 68.1 (nm), the AP from 37.6 to 48 (nm/s) and the VAS from 90.0 to 27.3 (mm).
The study showed that soft tissue manipulation was more effective than rest as a strategy to return muscles to a normal state and caused more relief in perceived fatigue.