The Effects Of Low Intensity Resistance Training With Blood Flow Restriction On Collegiate Student Athletes With Patellofemoral Pain

Objective:Patellofemoral pain(PFP)is a very common complaint in athletes who participate in running and jumping sports.High-intensity resistance training of quadriceps(HI-RT)was the standard intervention for patients with PFP in practice.However,for many athletes with PFP,the joint loads in HI-RT may increase the risk of injury and limit the implementation.Recently,low-intensity resistance training with blood flow restriction(LI-BFR)used in musculoskeletal rehabilitation of the general population has been described as a new way to improve muscle strength and volume.The aim of this study was to evaluate the effects of LI-BFR on the pain degree,patellofemoral function,mental state and quality of life among collegiate student athletes with PFP compared with HI-RT.This study could provide theoretical basis for the optimal treatment and management for athletes with PFP and promote the further application of LI-BFR as a new treatment in the field of musculoskeletal rehabilitation.Methods:56 collegiate student athletes who meet the inclusion criteria were randomly allocated to the control(CON)group,HI-RT group,or to LI-BFR group.The CON group did not receive any interventions.The HI-RT group received the conventional rehabilitation program 3 times a week for a total of 8 weeks,including stretching exercises,hip abduction and external rotation muscles resistance training,and HI-RT of the quadriceps.The LI-BFR group received a new rehabilitation program 3 times a week for a total of 8 weeks,including stretching exercises,hip abduction and external rotation muscles resistance training,and LI-BFR of the quadriceps.The tested items included the pain intensity evaluated by Visual Analogue Score(VAS),patellofemoral function evaluated by Anterior Knee Pain Scale(AKPS),volume and strength of quadriceps measured by Color Doppler Ultrasound and isokinetic muscle strength test machine,strength of abduction and external rotation muscle of hip measured by Micro FET3.Moreover,we also evaluated mental state of atheletes with Hospital Anxiety and Depression Scale(HADS),Tampa Scale of Kinesiophobia(TSK),and Pain Catastrophizing Scale(PCS).The quality of life also tested with Short Form Health Survey 36(SF-36).The test time mainly included baseline,four-week post-intervention,and eight-week post-intervention.The two-way repeated-measures ANOVA and generalized estimated equation were performed to compare the threeinterventions.A p-value of less than 0.05 was considered to be statistically significant.These analyses used the SPSS Statistics Software version 24.0 for statistical analysis.Results:(1)There were 16 athletes in each group for analysis.Baseline demographic characteristics were analyzed and there were no statistically significant differences among the three groups(P>0.05).(2)The results of pain intensity assessment showed:(1)The VAS scores in LI-BFR and HI-RT groups were both significantly lower than CON group after 8weeks of intervention(P<0.05).The VAS scores were better improved in LI-BFR group than in the HI-RT group,but there were no significant differences between the two groups(P>0.05);(2)The VAS scores during quadriceps resistance training decreased gradually over time in LI-BFR and HI-RT groups(P<0.05).The VAS scores during quadriceps resistance training in LI-BFR group were generally lower than HI-RT group,and there were significant differences in the first nine interventions between two groups(P<0.05).(3)The results of patellofemoral function evaluation showed: Although the AKPS scores in LI-BFR and HI-RT groups were both significantly lower than CON group after 8 weeks(P<0.05),the AKPS scores in LI-BFR group showed the differences after 4 weeks(P<0.05).(4)The results of strength and volume of quadriceps,strength of hip abduction and external rotation muscles tests showed:(1)The thickness of rectus femoris,vastus intermedius,vastus lateralis,vastus medialis,relative peak torque and power in LI-BFR and HI-RT groups were significantly improved after 8 weeks of intervention compared with the baseline(P<0.05),but there were no significant differences between the two groups(P>0.05).(2)The strength / weight ratios of hip abduction and external rotation muscles in LI-BFR and HI-RT groups showed a similar significant increase after 8 weeks of intervention compared with the baseline(P<0.05),and there were no significant differences between the two groups(P>0.05).(5)The results of mental state evaluation showed: The scores of all psychological scales significantly improved after 8 weeks of intervention compared with the baseline(P<0.05),except for the scores of HADS depression.The HADS anxiety scores and TSK scores in LI-BFR group were significantly lower than those of CON group after 8 weeks(P<0.05).However,compared with CON group,there were no significant differences in HI-RT group.We also observed that the PCS scores in LI-BFR group were significantly lower than those of CON group after 4 weeks(P<0.05),but the differences were not shown in HI-RT group until 8 weeks after intervention.(6)The results of quality of life evaluation showed: The scores of physical functioning,role-physical,bodily pain,general health,vitality and role-emotional in LI-BFR and HI-RT groups significantly improved after 8 weeks of intervention compared with the baseline(P<0.05).The scores of social function and mental health were also significantly improved compared with the baseline(P<0.05),and the scores of mental health in LI-BFR were significantly improved than CON group after 8 weeks(P<0.05).Conclusion:(1)Compared with the HI-RT(70% 1RM)in conventional rehabilitation protocols,the LI-BFR(30% 1RM,60% LOP)in the present study has not only achieved results in increasing muscle strength and volume with lower resistance load,but also effectively avoided the potential injury risk of HI-RT.It has lower pain levels during actual quadriceps resistance training,especially in the early stage of intervention.(2)Compared with conventional rehabilitation protocols,an eight-week LI-BFR protocol can also significantly improve the pain levels,patellofemoral function,negative psychological states and quality of life of collegiate student athletes with PFP.Furthermore,the LI-BFR protocol has partly demonstrated this improvement earlier and better.