M. Davis et al., ELECTROMYOGRAPH ANALYSIS OF THE POPLITEUS MUSCLE IN LEVEL AND DOWNHILL WALKING, Clinical orthopaedics and related research, (310), 1995, pp. 211-217
It has been proposed that the popliteus muscle is a source of lateral
knee pain, typically after downhill activities. Electromyography of th
e popliteus muscle was recorded in 9 normal subjects during level walk
ing, downhill walking, and walking downhill wearing a 40-lb backpack (
to simulate hiking). Popliteal muscle intensity during the midstance p
hase of walking downhill with weights increased significantly over tha
t of level walking (30% versus 13%, respectively) (p < 0.05). There wa
s a nonsignificant trend (p = 0.07) for a similar increase at terminal
swing (51% versus 36%). Significantly greater knee flexion was record
ed at loading response, midstance, and terminal stance (p < 0.01) duri
ng both downhill trials as compared with level walking, Initial contac
t position showed no differences. Velocities for downhill walking (72.
9 m/min) and downhill walking with weights (71.1 m/min) were significa
ntly less than those of level walking (83.9 m/min) (p < 0.01), Stride
analysis showed no significant difference in stance phase duration or
in initial double-limb support times between level walking and either
downhill condition. These data suggest that increased popliteal muscle
activity during midstance in downhill walking with weights is in resp
onse to weight bearing with an increased load on a flexed knee. Increa
sed Electromyographic activity may be associated with overuse of the p
opliteus muscle.