An investigation into the effect of a high velocity low amplitude manipulation on core muscle strength in patients with chronic mechanical lower back pain
Brunarski (1984) says that philosophically and historically, chiropractic has been uniquely orientated toward an emphasis on preventative care and health maintenance with a mechanistic and hands-on model for treatment. Instead of reductionism, chiropractors focus on holism, non-invasiveness and the sharing of the responsibilities for healing between doctor and patient. As stated in a Canadian report by Manga et al. (1993), lower back pain is a ubiquitous problem and there are many epidemiological and statistical studies documenting the high incidence and prevalence of lower back pain (Manga et al., 1993). Evans and Oldreive (2000) revealed in a study of the transversus abdominis that low back pain patients had reduced endurance of the transverses abdominis and that its protective ability was decreased. In addition, it was noted that wasting and inhibition of the other core stabiliser and co-contractor, multifidus, was present (Hides et al.,1994), both of which have been linked to the presence of low back pain (Evans and Oldreive, 2000 and Hides et al., 1994). Thus, it stands to reason that manipulation, as an effective treatment for low back pain (Di Fabio, 1992), could be effective in restoring the strength and endurance of the core stability muscles. This is theoretically supported by the fact that a restriction in motion and pain due to mechanical derangement in the low back can be effectively treated by manipulation (Sandoz, 1976; Korr (Leach, 1994); Herzog et al., 1999; Homewood, 1979; Vernon and Mrozek, 2005 and Wyke (Leach, 1994)). Homewood (1979) described that a subluxation may interfere with the nerve supply and result in a decrease in muscular activity. He hypothesized that removal of the subluxation could restore: normal physiological processes, increase muscle activity and; improve functional ability and normalize the torque ratios (Herzog et al., 1999; Korr (Leach, 1994); Nansel et al., 1993 and Rebechini-Zasadny et al., 1981). In terms of an intervention, Rebechini-Zasadny et al. (1981) and Naidoo (2002) demonstrated and inferred that manipulation to the cervical spine could affect the muscular activity supplied by those levels. They, however, suggested further studies of manipulation-induced peripheral changes in the muscles are needed, due to unaccounted for variables and small sample sizes in their respective studies This research aims to address the questions posed by the above literature, hence by investigating a high velocity low amplitude manipulation as a possible added intervention for improving local core stabilizer muscle strength, a management protocol for the chronic mechanical lower back pain could be developed.