Research Review by Dr. Shawn Thistle©

Date:

Oct. 2007

Study Title:

The effect of combining manual therapy with exercise on the respiratory function of normal individuals: A randomized control trial

Authors:

Engel RM & Vemulpad S

Publication Information:

Journal of Manipulative and Physiological Therapeutics 2007; 30: 509-513.

Summary:

It is noteworthy that 20% of all deaths worldwide are attributable to dysfunction of the respiratory system, with non-communicable conditions responsible for approximately one third of those. This trend is destined to increase as the population in general ages.

Assessing respiratory function is not normally conducted in a formal (physiological) manner in most manual therapy practices. That being said, many manual therapists are concerned with the musculoskeletal aspects of breathing, and their consequences on human health and performance.

It is generally thought that “normal” respiratory function begins to decline after age 25. In a laboratory setting, respiratory function is often assessed using spirometry – with common measures including forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). Normal ranges for these measures vary depending on age, gender, and height. Studies utilizing these measures estimate that anywhere between 3-8% of people in the USA show signs of COPD. Although somewhat controversial, one factor discussed in older literature and thought to be particularly important in determining the rate of respiratory decline is a history of recurrent respiratory tract infections (RTI) in childhood. It has been suggested that recurrent RTIs in childhood may correlate with future incidence of chronic obstructive pulmonary disease (COPD), which is characterized by progressive, irreversible airflow changes. COPD is usually clinically silent in the early stages, so initial diagnosis is critical to improving prognosis.

In light of the hypothesis that adult decline in respiratory function may stem from childhood – it may be pertinent to explore interventions that may positively impact respiratory function in seemingly normal individuals. It has been suggested that manual therapy aimed at the thoracic spine and rib articulations can improve respiratory function in asymptomatic individuals. This is based on the concept that thoracic cage mobility can influence respiratory function, a tenet generally accepted in the fields of respiratory physiology and functional anatomy.

This study aimed to measure the effect of manual therapy and exercise on the respiratory function of normal individuals. 20 healthy volunteers between the ages of 18-28 who were non-smokers for at least 12 months and who were not taking any respiratory medications were randomized into four groups as follows (n=5 in each group):
  1. Exercise Only Group - underwent a standardized 15 minute treadmill walking program adhering to specific pace, inclination, and duration – 6 sessions over a 4-week period
  2. Manual Therapy Only Group - received (nondescript) soft tissue therapy and spinal and/or rib manipulation (high-velocity, low-amplitude) to the lower cervical and thoracic spines, and associated ribs – 6 sessions over a 4-week period
  3. Manual Therapy and Exercise - a combination of the two interventions (manual therapy followed by the exercise protocol) – 6 sessions over a 4-week period
  4. Control Group - received no intervention
All participants underwent standard spirometry testing (including FVC and FEV1 measurements) at two week intervals starting at study inception.

Spirometry measurements were taken 1 minute before and 1 minute after each intervention (note: for group 3, measures were done before and after manual therapy, and then after the exercise protocol).

Pertinent Results:

  • participants in the “exercise only” group had a statistically significant decrease in FVC and FEV1 – this may be explained by increased exercise-induced respiratory resistance
  • participants in the “manual therapy only” group had a statistically significant increase in FVC and FEV1 after treatment
  • participants in the combination manual therapy/exercise group had a significant increase in FVC and FEV1 after manual therapy, followed by additional gains after exercise (overall, this increase was not statistically significant)
  • the nature and extent of the changes in the two groups receiving manual therapy was similar
  • overall, the control group had lower FVC values, and showed no change in either FCV or FEV1 values throughout the study

Conclusions & Practical Application:

This small study provides preliminary evidence that manual therapy in the form of soft tissue therapy and manipulation of the lower cervical/thoracic spinal and rib articulations can have an immediate, positive impact on respiratory function in asymptomatic subjects. It is interesting to note that manual therapy also seemed to reverse the trend for negative effects of exercise on FVC and FEV1, a finding that would be more compelling if reproduced in a larger study. These findings highlight a potential role for manual therapy in treating respiratory dysfunction (ex. manipulating patients before exercise in a pulmonary rehabilitation setting?), and should stimulate more research in this area.

The results of this study should be considered keeping some weaknesses in mind:
  • the sample size was small – limiting the statistical power of this study
  • the intervention groups were not matched to age or gender (although the range of patient ages was small [early 20s]) – this would have been difficult anyway due to the small sample size
  • the exercise protocol was only 15 minutes long – arguably not long enough to create a true exercise adaptation
  • respiratory function was assessed in the very short-term (i.e. immediately post-intervention); hence the long-term effects cannot be elucidated
Further studies are required to replicate and build on these findings, particularly those involving patients with existing respiratory conditions, or those deemed to be at high risk.