EMG of the hip adductor muscles in six clinical examination tests.
OBJECTIVE
To assess activation of muscles of hip adduction using EMG and force analysis during standard clinical tests, and compare athletes with and without a prior history of groin pain.


METHODS
Controlled laboratory study.


METHODS
21 male athletes from an elite junior soccer program.


METHODS
Bilateral surface EMG recordings of the adductor magnus, adductor longus, gracilis and pectineus as well as a unilateral fine-wire EMG of the pectineus were made during isometric holds in six clinical examination tests. A load cell was used to measure force data.


RESULTS
Test type was a significant factor in the EMG output for all four muscles (all muscles p < 0.01). EMG activation was highest in Hips 0 or Hips 45 for adductor magnus, adductor longus and gracilis. EMG activation for pectineus was highest in Hips 90. Injury history was a significant factor in the EMG output for the adductor longus (p < 0.05), pectineus (p < 0.01) and gracilis (p < 0.01) but not adductor magnus. For force data, clinical test type was a significant factor (p < 0.01) with Hips 0 being significantly stronger than Hips 45, Hips 90 and Side lay. BMI (body mass index) was a significant factor (p < 0.01) for producing a higher force. All other factors had no significant effect on the force outputs.


CONCLUSIONS
Hip adduction strength assessment is best measured at hips 0 (which produced most force) or 45° flexion (which generally gave the highest EMG output). Muscle EMG varied significantly with clinical test position. Athletes with previous groin injury had a significant fall in some EMG outputs.
Australian Institute of Sport (AIS), Dept. of Sports Medicine, Leverrier St., Bruce, ACT 2617, Australia. greg.lovell@ausport.gov.au
Gregory A
GA
Lovell
Peter D
PD
Blanch
Christopher J
CJ
Barnes
D000293:Adolescent; D016001:Confidence Intervals; D004576:Electromyography; D006621:Hip Joint; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D009141:Musculoskeletal System; D010808:Physical Examination; D012916:Soccer; D013178:Sports Medicine