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

Thorax. 2014 Jun;69(6):525-31. doi: 10.1136/thoraxjnl-2013-204388. Epub 2014 Jan 7.


Rationale: Strength training and neuromuscular electrical stimulation (NMES) improve lower-limb muscle function in dyspnoeic individuals with chronic obstructive pulmonary disease (COPD). However, high-frequency NMES (HF-NMES) and strength training have never been compared head-to-head; and effects of low-frequency NMES (LF-NMES) have never been studied in COPD. Therefore, the optimal training modality to improve lower-limb muscle function, exercise performance and other patient-related outcomes in individuals with severe COPD remains unknown.

Objectives: To study prospectively the efficacy of HF-NMES (75 Hz), LF-NMES (15 Hz) or strength training in severely dyspnoeic individuals with COPD with quadriceps muscle weakness at baseline.

Methods: 120 individuals with COPD (FEV1: 33±1% predicted, men: 52%, age: 64.8±0.8 years) were randomised to HF-NMES, LF-NMES or strength training as part of a comprehensive inpatient pulmonary rehabilitation programme. No treadmill walking or stationary cycling was provided.

Measurements and main results: Groups were comparable at baseline. Quadriceps muscle strength increased after HF-NMES (+10.8 Newton-metre (Nm)) or strength training (+6.1 Nm; both p<0.01), but not after LF-NMES (+1.4 Nm; p=0.43). Quadriceps muscle endurance, exercise performance, lower-limb fat-free mass, exercise-induced symptoms of dyspnoea and fatigue improved significantly compared with baseline after HF-NMES, LF-NMES or strength training. The increase in quadriceps muscle strength and muscle endurance was greater after HF-NMES than after LF-NMES.

Conclusions: HF-NMES is equally effective as strength training in severely dyspnoeic individuals with COPD and muscle weakness in strengthening the quadriceps muscles and thus may be a good alternative in this particular group of patients. HF-NMES, LF-NMES and strength training were effective in improving exercise performance in severely dyspnoeic individuals with COPD and quadriceps weakness.

Trial registration: NTR2322.

Keywords: COPD Pathology; Exercise; Pulmonary Rehabilitation.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activities of Daily Living
  • Aged
  • Body Composition
  • Dyspnea / physiopathology
  • Dyspnea / rehabilitation*
  • Electric Stimulation Therapy / methods*
  • Exercise / physiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Muscle Strength* / physiology
  • Muscle Weakness / physiopathology
  • Muscle Weakness / rehabilitation*
  • Prospective Studies
  • Pulmonary Disease, Chronic Obstructive / physiopathology
  • Pulmonary Disease, Chronic Obstructive / rehabilitation*
  • Quadriceps Muscle*
  • Resistance Training / methods*
  • Single-Blind Method