title: The soleus muscle acts as an agonist for the anterior cruciate ligament. An in vitro experimental study.
abstract: BACKGROUND
  Although the quadriceps muscles are known antagonists for the anterior cruciate ligament and the hamstring muscles are known agonists, the influence of the calf muscles on knee stability is not well understood.
  
  
  OBJECTIVE
  The soleus muscle acts as an anterior cruciate ligament agonist and the gastrocnemius muscle acts as an anterior cruciate ligament antagonist.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Six cadaveric knees were tested with individual and combined activation of the gastrocnemius and soleus muscles to determine the influence of simulated muscle contraction on tibiofemoral motion.
  
  
  RESULTS
  At all flexion angles, applying the soleus muscle force tended to translate the tibia posteriorly, whereas applying the gastrocnemius muscle force tended to translate the tibia anteriorly. Applying the soleus and gastrocnemius muscle forces together also tended to translate the tibia anteriorly. The average anterior and posterior tibial translations were greatest at 50 degrees of flexion.
  
  
  CONCLUSIONS
  The soleus muscle is capable of acting as an agonist for the anterior cruciate ligament and the gastrocnemius muscle can act as an antagonist.
  
  
  CONCLUSIONS
  A better understanding of the agonistic behavior of the soleus muscle on the anterior cruciate ligament may lead to the development of training and rehabilitation strategies that could reduce the incidence of injury and improve function in both patients with anterior cruciate ligament deficiency and patients who have undergone anterior cruciate ligament reconstruction.
authors.affiliation: Department of Orthopaedic Surgery and the Orthopaedic Biomechanics Laboratory, Johns Hopkins University, Baltimore, Maryland 21093, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Elias
authors.forename: Alfred F
authors.initials: AF
authors.lastname: Faust
authors.forename: Yung-Hua
authors.initials: YH
authors.lastname: Chu
authors.forename: Edmund Y
authors.initials: EY
authors.lastname: Chao
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Cosgarea
mesh_terms: D000368:Aged; D016118:Anterior Cruciate Ligament / Q000502:physiology*; D001696:Biomechanical Phenomena; D002102:Cadaver; D005269:Femur / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D012399:Rotation; D013314:Stress, Mechanical; D013977:Tibia / Q000502:physiology*