Efficacy of lower-limb muscle training modalities in severely dyspnoeic individuals with COPD and quadriceps muscle weakness: results from the DICES trial

RATIONALE: Strength training and neuromuscular electrical stimulation improve lower-limb muscle function in dyspnoeic individuals with chronic obstructive pulmonary disease (COPD). However, high-frequency NMES (HF- strength training have never been compared head-to-head; and effects of low-frequency NMES (LF-NMES) have never been studied in COPD. Therefore, optimal training modality to improve lower-limb muscle function, performance and other patient-related outcomes in individuals with remains unknown. OBJECTIVES: To study prospectively the efficacy of HF- Hz), LF-NMES (15 Hz) or strength training in severely dyspnoeic COPD with quadriceps muscle weakness at baseline. METHODS: 120 COPD (FEV1: 33+/-1% predicted, men: 52%, age: 64.8+/-0.8 years) were to HF-NMES, LF-NMES or strength training as part of a comprehensive pulmonary rehabilitation programme. No treadmill walking or stationary was provided. MEASUREMENTS AND MAIN RESULTS: Groups were comparable at Quadriceps muscle strength increased after HF-NMES (+10.8 Newton-metre strength training (+6.1 Nm; both p<0.01), but not after LF-NMES (+1.4 p=0.43). Quadriceps muscle endurance, exercise performance, lower-limb mass, exercise-induced symptoms of dyspnoea and fatigue improved compared with baseline after HF-NMES, LF-NMES or strength training. The in quadriceps muscle strength and muscle endurance was greater after HF- after LF-NMES. CONCLUSIONS: HF-NMES is equally effective as strength severely dyspnoeic individuals with COPD and muscle weakness in quadriceps muscles and thus may be a good alternative in this particular patients. HF-NMES, LF-NMES and strength training were effective in exercise performance in severely dyspnoeic individuals with COPD and weakness. TRIAL REGISTRATION: NTR2322.