Respiratory Muscle Training - The New Training

Research into respiratory muscle training has been ongoing since the 1970’s. However, results are conflicting most likely due to the different forms of training such as pressure-threshold training, voluntary hyperventilation and hypercapnic (increased CO2) hyperventilation; and the variety of outcome measures used……. These conflicting results have led to confusion as to whether there is any benefit to exercise performance from respiratory muscle training. There are now many devices on the market all promising to reduce your marathon time or increase your feelings of comfort during exercise such as Powerlung, Powerbreathe and Expand-a-lung. However, with technological advances and our increased scientific understanding, the current consensus of opinion is that respiratory muscle training does indeed help with exercise performance in healthy and clinical populations.

The mechanism of this effect seems to be two-fold :

1. An altered perception of breathing effort and exercise load, meaning that the exercise feels easier, this psychological effect shouldn’t be underestimated in fatiguing exercise!
2. A delayed metaboreflex, meaning that blood is not diverted from the skeletal to the respiratory muscles until higher exercise intesnities, allowing exercise at higher intensities to be maintained for longer (Romer & Dempsey, 2006).

Taken together these effects can be as large as a 4% increase in a 40Km cycling time-trial performance, which is substantial.

It has been demonstrated that acute (within 1 training session) vibration stimulation of exercising skeletal muscle enhances skeletal muscle activity and strength performance after 1 session (Mileva et al., 2006) and chronic training with superimposed vibration has been shown to increase strength up to 300% more than conventional strength training (Issurin et al., 1994). Vibration has also been applied to the respiratory musculature with demonstrable increases in respiratory nerve activity, reduced breathlessness in healthy humans and reduced breathlessness during exercise in chronic obstructive pulmonary disease patients (COPD; Fujie et al., 2002).

Until recently vibration had never been applied to a training device for the respiratory system, so we applied rapid airway occlusions simulating vibration effects on the respiratory system (youbreathe). Preliminary results show that 10 breaths through youbreathe acutely augment breathing power by around 15%, compared to no augmentation after 10 breaths of breathing against matched resistance. These results are now published in Respiration Physiology & Neurobiology and further work examining the long term training benefits of youbreathe are under way.

Collaborations are also under way with clinical partners to assess the efficacy of youbreathe in complementing respiratory physiotherapy with youbreathe in cystic fibrosis and chronic obstructive pulmonary disease patients. We are testing the hypothesis that the percussive effects of youbreathe may facilitate the removal of mucus leading to improved respiratory function in these patients.

In summary, research into respiratory muscle training is now gaining real credibility, but we are still at the dawn of our understanding of vibration training. Many issue remain to be resolved such as the mechanism of action and appropriate vibration prescription for desired effects. The potential benefits of respiratory vibration have not yet been fully explored, however this new intervention offers exciting potential to scientists, athletes and patients alike.

Dr Paul Sumners is a neuroscientist at London South Bank University investigating the effects of vibration training in health and disease.