generated. The hypothesis is that the lead

hip (left leg in a right handed golfer) acts as the primary pivot point and so experiences a significant amount of torque. Repetitive motion and overuse may result in micro-trauma that presumably leads to capsular contracture and range of movement deficits (18).

It has therefore been postulated

that lower back pain in golfers may be secondary to limited rotation range of

movement in the hip joint (7), with one study finding that professional golfers demonstrated a significant correlation between hip inward rotation range of movement deficit and the incidence of lower back pain (18). This is the only such study

undertaken with golfers. In this instance the subjects were professionals and are therefore not necessarily representative of the total golfing population and may not be transferable or inferred to the amateur golfing population as a whole. This study (18) again speculates

about the various diagnoses and causes for the back pain as well as the limitations of range of movement. This is a conceptual problem, as no clinical diagnosis or attempt to define/categorise the nature of the low back pain has been made. This would have severely increased the duration of testing, the financial cost of the study and ultimately its viability. It was therefore unrealistic to make a diagnosis at this time. A lack of a specific diagnosis may also limit the generalisability of the study. The study (18), like most of the published literature in this area is further compounded by the fact that as an observational cross sectional study, the findings are only indicative of one moment in time. The data collection is undertaken at one point in time and only allows a snap shot of reference. It

12

can only provide prevalence data, with no information about incidence. These observational studies cannot determine the order in which elements occurred, whether low back pain was as a result of hip rotation deficit or vice versa. There is no inference of causality and it cannot be ascertained as to which variable is having an effect on the other and therefore the relationship direction cannot be determined. All that can be established is whether there is a correlation between the two variables. A ‘self reported’ history of injury, will also induce an element of recall bias, which is especially significant in a study which asks to report injury throughout a subject’s entire career (4). In this particular study (4), dancers had to report any back or lower limb injury that impacted on their ability to practice or perform during their whole dance career. This was in contrast to most of the other studies which only requested a self reported injury history within the previous twelve months (1, 2, 3, 5, 18). There is likely to be a variation in injury recall between study subjects; those who sustained a more severe injury may be more likely to remember the incident than those who had suffered a relatively mild injury, and an injury which was notable to one subject may not be deemed notable to another. Self defining an injury is largely subjective and once again raises the issue of study applicability and generalisability to the larger population. Unrelated subject design means that individual differences among the non-randomised groups may distort the results. Such confounding variables between the groups may mean they are neither in fact comparable nor representative. Ideally participants should only differ with respect to the variable of interest.

The study subjects were not matched, therefore did not avoid these potential confounding variables. The relationship between low back pain and hip rotation deficit may well be confounded by age or gender, although this was not found to be the case in a number of studies (1, 2).

The most important aspect of defining an injury is identifying that the injury can be in fact attributable to golf. It must be considered that golfers may have physically demanding jobs or may regularly participate in other sports that could combine with golf

sportEX medicine 2008;37(Jul):10-14