Effects Of Whole-body Vibration Combined With Hip And Knee Strengthening Training On Biomechanical Characteristics Of Lower Limbs In Patients With PFPS

Objective: Based on the results of the previous study,the aim of this study is to explore the effects of whole-body vibration training combined with hip and knee strengthening training on the biomechanics mechanism of the lower extremity in patients with patellofemoral pain syndrome and to analyze the possible reasons for the long-term efficacy of the combined intervention over hip and knee strengthening training alone.Methods: A total of 36 subjects were recruited and randomly allocated into group HK（n = 18）: hip and knee intensive training group（n = 18）and group WHK（n = 18）:whole-body vibration training combined with hip and knee strengthening training group.Both groups received a total of 6 weeks of intervention training.The evaluator was blinded.The visual analogue pain score（VAS）,the peak ground reaction force during the jogging support period,the lower limb joint angle peak value during the jogging support period,and the lower limb joint angle peak value in the squat mode were evaluated before and after the intervention.Data were processed by the self-developed code in Matlab 2020 b and SPSS 24.0.The results were shown by the mean and standard deviation（Mean ± SD）.P < 0.05 was set as the significant level.Results: This study used a two-way repeated-measures analysis of variance.The results showed that there was no interaction effect of time × group in the VAS scores（P = 0.78）,but it decreased significantly after intervention in both groups（P = 0.01）.Comparing the peak value of ground reaction force between the two groups,only the peak value of ground reaction force in the inner and outer directions of group WHK was significantly decreased after the intervention（P = 0.05）,and was significantly lower than that of group HK（P = 0.04）.Comparison of the peak lower extremity joint angle between the two groups during the jogging support period: the peak knee adduction angle had no interaction effect on time × group（P = 0.19）,but group WHK showed was significantly increased after intervention（P = 0.02）.Peak ankle dorsiflexion angle had no interaction effect on time × group（P = 0.22）,but group WHK showed decreased significantly after intervention（P = 0.01）.There was no interaction effect for peak ankle plantarflexion angle at time × group（P = 0.67）,but group HK showed increased significantly after the intervention（P = 0.04）.There was no interaction effect on time × group for peak ankle varus angle（P = 0.46）,but group WHK showed decreased significantly after the intervention（P = 0.04）.Comparison of the peak lower extremity joint angle between the two groups in squat mode: only the peak knee adduction angle in group WHK was significantly reduced after the intervention（P = 0.02）,and there was no interaction effect between time and group（P= 0.57）.Conclusion: The effect of whole-body vibration combined with hip and knee strengthening training is better than that of hip and knee strengthening training alone.The whole-body vibration combined with hip and knee strengthening training reduced the internal and external ground reaction force and reduced the excessive activity of the joint.This is beneficial to improve the biological force line of the lower extremities,which may be the reason why the curative effect is maintained for a long time.