Robot-Assisted Multi-limb Joint Muscle Strength Training and Performance Evaluation

Muscle strength training can effectively reduce muscle atrophy, activate muscle tissue and promote muscle strength recovery and growth. Based on our previous research, we developed four muscle strength training strategies by further imitating the clinical muscle strength training methods, namely, Isokinetic centriPetal-centriPetal Exercise (IPPE), Isokinetic centriPetal-centriFuge exercise (IPFE), Isokinetic centriFuge-centriPetal Exercise (IFPE) and Isokinetic centriFuge-centriFuge Exercise (IFFE). To quantitatively evaluate the performance of the developed strategies, experiments were carried out with elbow and knee joints as examples, and muscle Endurance Ratio (ER), Flexion and Extension torque ratio (F/E) and the degree of muscle activation were extracted and calculated based on angle/torque and Surface ElectroMyoGraphy (sEMG) signals. Experimental results showed that the ER value of IFFE was significantly reduced compared with IPPE, while the F/E value of IFPE was significantly increased; this suggests that muscle centrifugation corresponds to higher training intensity; In addition, flexor and extensor muscle groups showed different levels of muscle activation in different training strategies. The results reveal that combining different muscle movement characteristics, isokinetic exercise can exert special muscle strength training effects. The study can lay the foundation for exploring subject-specific adaptive muscle strength training strategies to better adapt to different levels of muscle strength.