Effects Of Home-based Lower Limb Strength Training On The Muscle Strength And Function In Patients With Stable Chronic Obstructive Pulmonary Disease

Objective. This study aimed to design the exercise prescription of home-based lower limb strength training, and to identify the effect of this specific training in patients with stable chronic obstructive pulmonary disease(COPD). We tried to provide scientific evidence for the development of simple, safe and feasible home-based lower limb strength training interventions for stable COPD patients.Methods. This study was composed of two parts. Part I: Formulating the prescription of home-based lower limb strength training by means of literature review and expert consultations. Home-based lower limb strength training include:(1) Six sets of lower limb training(including: straight leg lifting exercises, prone hip extension exercises, thigh abduction exercises, posterior muscle group exercises, prior and posterior muscle group exercises, standing calf raise), using the method of self-gravity resistance and Thera-band resistance, 8~12RM, 20~30min/session, 3 sessions/week, for a duration of 12 weeks. Part II: We conducted a 12-week randomized controlled trial. Patients who met our inclusion criteria were randomized into the intervention group(n=25) and the control group(n=22).Intervention group received routine pulmonary rehabilitation guidance and home-based lower limb strength training while control group received routine pulmonary rehabilitation guidance. Both groups received scheduled telephone visits, and intervention group had additional home visits if necessary. The muscle strength, five repetition sit-to-stand test,six-minute walk distance, Modified Medical Research Council dyspnea scale, quality of life were compared at enrollment and at 12 weeks.Results.1.There was no statistically significant difference between the control group and the experimental group in baseline data(P > 0.05).2.At week 12, compared with at enrollment, improvements in all indexes of muscle strength(isometric extensor muscle peak torgue, isometric extensor muscle peak TQ/BW,isokinetic extensor muscle peak torgue, extensor muscle peak TQ/BW) in the intervention group yielded statistical significance(P<0.05).Improvement in isometric extensor muscle peak torgue in the control group indicated statistical significance(P=0.017),no significant difference was observed in other indexes of muscle strength in the control group(P>0.05);At week 12, decrease in FTSST in the intervention group compared with that at enrollment yielded statistical significance(P=0.010). However, there was no significant difference in the control group(P>0.05); At week 12, intra-group comparison showed that increase in6 WMD in both groups compared with that at enrollment yielded statistical significance(P=0.014,P=0.018).3.At week 12, there was intra-group effect in the intervention group on the decrease of m MRC(P=0.045) while there was no significant difference in the control group(P>0.05);At week 12, within intervention group, compared with at enrollment, deceases in CAT total scores, cough scores, expectoration scores, chest distress scores, feeling of climbing uphill or climbing stairs scores and confidence in going outside scores yielded statistical significance(P<0.05). No significant difference was observed in the other items of CAT in the intervention group(P>0.05). In the control group, there was significant decease in scores of confidence in going outside(P=0.035). No significant difference was observed in the other items of CAT in the control group(P>0.05); At week 12,intra-group comparison showed that,compared with at enrollment, mean scores of activities of daily living and anxiety yielded statistical significance in the intervention group(P<0.05) as well as in the control group(P <0.05). In addition, compared with at enrollment, total mean score of COPD_Qo L within the control group yielded statistical significance(P < 0.05), no significant difference was observed in the other items of COPD_Qo L in the control group(P>0.05).Conclusion. In this study, the exercise prescription of home-based lower limb strength training in patients with stable COPD was formulated. Like the routine pulmonary rehabilitation guidance, home-based lower limb strength training can imporove the muscle strength, exercise endurance, confidence in going outside scores, activities of daily living and anxiety status. Compared with routine pulmonary rehabilitation guidance, home-based lower limb strength training can improve the muscle strength, lower limb function and the COPD symptoms(dyspnea score, cough scores, expectoration scores, chest distress scores,feeling of climbing uphill or climbing stairs scores) more effectively. Therefore, it is recommendable forpatientswithstable COPD.