Electromyography of the trunk and abdominal muscles in golfers with and without low back pain.

Twelve male golfers who experienced low back pain (LBP) whilst playing or practicing golf and 18 asymptomatic golfers were recruited and divided into handicap-specific groups; low-handicap golfers, with a handicap between 0 and 12 strokes; and high-handicap golfers, with a handicap of between 13 and 29 strokes. The myoelectric activity of the lumbar erector spinae (ES) and the external obliques (EO) was recorded via surface electromyography (EMG), whilst the golfers performed 20 drives. The root mean square (RMS) was calculated for each subject and the data for the ES and EO were normalised to the EMGs recorded whilst holding a mass equal to 5% of the subjects' body mass at arms length and whilst performing a double-leg raise, respectively. The results showed that the low-handicap LBP golfers tended to demonstrate reduced ES activity at the top of the backswing and at impact and greater EO activity throughout the swing. The high-handicap LBP golfers demonstrated considerably more ES activity compared with their asymptomatic counterparts, whilst EO activity tended to be similar between the high-handicap groups. The reduced ES activity demonstrated by the low-handicap LBP group may be associated with a reduced capacity to protect the spine and its surrounding structures at the top of the backswing and at impact, where the torsional loads are high. When considering this with the increased EO activity demonstrated by these golfers, it is reasonable to suggest that these golfers may be demonstrating characteristics/mechanisms that are responsible for or are a cause of LBP.