Abstract
Hamstring injuries are common among athletes and recreationally active people. Therefore, novel methods of rehabilitations are important based on the rate of injury.
PURPOSE: To determine the function and effectiveness of a Hamstring device in assisting the biceps femoris and semitendinosus in flexion of the knee.
METHODS: The experimental design was a within-subject design. Electrodes were placed on the biceps femoris and semitendinosus in a bipolar configuration on the dominate leg of all the subjects (n=12) in order to monitor muscle activity during the experimental procedure. The test involved isometrically holding 15, 30, 45 and 60% of the participant’s pre-determined maximum isometric force at 90 and 135 degrees knee flexion with and without the Hamstring apparatus. The raw EMG signal was low-pass filtered and amplified prior to being interpreted by AcqKnowledge software and peak EMG signals was resolved via the software and imported into SPSS ver 21.0 for analysis.
RESULTS: There was a significant difference in the EMG signal (Mean Diff: 0.049 mV p<0.05) at 135 degrees of flexion in the biceps femoris at 15%. There was no significant difference in any other EMG signals. However, there seemed to be an overall trend for reductions in peak EMG signals with the device. Overall, clinical inferences revealed that the device could be considered 71.4% beneficial or substantially positive for reducing the EMG signal associated with isometric exercise in the biceps femoris (biceps femoris mean with device 0.319mV±0.13 and without 0.361mV±0.14). Similarly, 6 out of 8 conditions resulted in lower muscle activation from the semitendinosus with the apparatus. For the semitendinosus muscle, clinical inferences suggest that the device was 43.9% beneficial (semitendinosus mean with device 0.327mV±0.09 and without 0.339mV±0.09).
CONCLUSIONS: The reduction in electrical activity of the biceps femoris and the semitendinosus during the isometric hold with the Hamstring apparatus suggests that the elastic Hamstring assistant device effectively assists in knee flexion and could potentially be used for rehabilitation purposes.