RESUMEN
OBJECTIVE: The objective of this study is to compare the effectiveness of lower limb low-load blood flow restriction training (LL-BFRT) with high-load strength training (HL-ST) as part of an outpatient pulmonary rehabilitation programme on leg strength in patients with chronic obstructive pulmonary disease (COPD). METHODS: Participants were randomised to LL-BFRT or HL-ST (24 sessions). LL-BFRT was done at 30% 1-repetition maximum (1-RM) with 70% arterial occlusion pressure. HL-ST was done at 70% 1-RM. Primary outcome was isometric strength of knee extensors and flexors. Secondary outcomes were 1-RM, functional exercise capacity, physical activity, symptom burden and health-related quality of life. Perceptions of dyspnoea and leg fatigue were recorded after every exercise. We compared groups with t-tests. RESULTS: We included 30 participants (13 women, 17 men, 64 (9) years, forced expiratory volume in 1 s 47 (18)% pred.), 24 completed the study. Isometric knee extensor strength improved to a clinically relevant degree in both legs in both groups (LL-BFRT: right leg 9 (20) Nm, left leg 10 (18) Nm; HL-ST: right leg 15 (26) Nm, left leg 16 (30) Nm, data are mean (SD)), without statistically significant or clinically relevant between-group differences (right leg mean difference= -6.4, 95% CI= -13.20 to 25.92 Nm, left leg mean difference= -5.6, 95% CI= -15.44 to 26.55 Nm). 1 min sit-to-stand test performance improved to a clinically relevant degree only in the LL-BFRT group (4 (4) vs 1 (5) repetitions). Interestingly, physical activity improved to a clinically relevant degree only in the LL-BFRT group (1506 (2441) vs -182 (1971) steps/day). LL-BFRT lowered perceived in-exercise dyspnoea and increased leg fatigue compared with HL-ST in the initial 12 trainings. CONCLUSION: In patients with stable COPD undergoing outpatient pulmonary rehabilitation, LL-BFRT was not superior to HL-ST in improving leg strength. LL-BFRT led to similar strength gains as HL-ST while reducing perceptions of dyspnoea in the initial training phase. TRIAL REGISTRATION NUMBER: NCT04151771.
Asunto(s)
Enfermedad Pulmonar Obstructiva Crónica , Entrenamiento de Fuerza , Masculino , Humanos , Femenino , Proyectos Piloto , Calidad de Vida , Terapia de Restricción del Flujo Sanguíneo , Método Simple Ciego , Enfermedad Pulmonar Obstructiva Crónica/rehabilitación , Disnea/etiología , Fatiga , Fuerza MuscularRESUMEN
OBJECTIVE: The purpose of this report is to describe the case of a patient with chronic obstructive pulmonary disease (COPD) who was load compromised and being referred for outpatient pulmonary rehabilitation. Low-load blood flow restriction strength training (LL-BFRT) was applied to prepare for and increase tolerability of subsequently applied high-load strength training. METHODS (CASE DESCRIPTION): A 62-year-old woman with COPD GOLD 2 B presented with severe breathlessness. Lower limb strength was severely reduced while functional exercise capacity was preserved. The patient was severely load compromised and had high risk to be intolerant of the high training loads required to trigger the desired adaptations. LL-BFRT was applied during the first 12 training sessions and high-load strength training in the subsequent 12 training sessions of the rehabilitation program. Endurance training on a cycle ergometer was performed throughout the program. RESULTS: Symptom burden in the COPD assessment test was reduced by 6 points (40%). Lower limb strength improved by 95.3 Nm (521%) and 88.4 Nm (433%) for the knee extensors and by 33.8 Nm (95%) and 56 Nm (184%) for the knee flexors, respectively. Functional exercise capacity improved by 44 m (11%) in the 6-minute walk test and 14 repetitions (108%) in the 1-minute sit-to stand test. The patient did not experience any adverse events related to the exercise training. CONCLUSION: Clinically relevant changes were observed in both strength-related functional and self-reported outcomes. The achievements translated well into daily living and enabled functioning according to the patients' desires. LL-BFRT was reported to be well tolerated and implementable into an outpatient pulmonary rehabilitation program. IMPACT: The description of this case encourages the systematic investigation of LL-BFRT in COPD. LL-BFRT has the potential to increase benefits as well as tolerability of strength training in pulmonary rehabilitation. Consideration of the physiological changes achieved through LL-BFRT highlights potential in targeting peripheral muscle dysfunction in COPD.