Evaluation of Anterior Tibial Translation and Muscle Activity during “Front Bridge” Quadriceps Muscle Exercise

Abstract

In a postoperative rehabilitation program following anterior cruciate ligament (ACL) reconstruction surgery, it is most important to avoid exerting excessive stress on the reconstructed graft. We have been using a quadriceps muscle exercise, “front bridge” which is carried out in the prone position.[Purpose]To analyze anterior tibial translation and quadriceps muscle activity during “front bridge” exercise.[Materials and Methods]Anterior displacement of the tibia were measured in two patients with ACL insufficiency during two kinds of front bridge exercises which place a fulcrum on the proximal (P-FB) and distal (D-FB) lower leg Muscular activity during P-FB and D-FB was also measured in nine healthy volunteers using electro-myography.[Results]From 30 to 0-degree of knee angle, the P-FB did not exerted anterior translation of the tibia in involved knees compared to that in uninvolved ones. Muscle activity of P-FB exercise was less than that of D-FB exercise even though muscle activity on P-FB exercise was larger than 60%MVC.[Discussion]The anterior tibial translation by quadriceps femoris muscular activity and the effects of gravity in the prone position was prevented by the reaction force produced from the proximal fulcrum on the lower leg. Because P-FB showed more than 60%MVC muscle activity, it was thought that the P-FB had the strengthening effect of the quadriceps femoris muscle. These results suggest that the front bridge exercise which places a fulcrum on the proximal lower leg is effective exercise for quadriceps femoris muscle training with safe following ACL reconstruction surgery.[Conclusion]The P-FB displayed more posterior tibial position than D-FB in extension position. Muscle activity of P-FB exercise was less than D-FB exercise. And also P-FB exercises had the strengthening effect of the quadriceps femoris muscle.Keywordsanterior cruciate ligament (ACL)anterior tibial translationfluoroscopyexercisequadriceps