diff --git a/doc/APIreference.rst b/doc/APIreference.rst
index 82731720..d9e69f29 100644
--- a/doc/APIreference.rst
+++ b/doc/APIreference.rst
@@ -367,7 +367,8 @@ mjtTrn
        mjTRN_SLIDERCRANK,              // force via slider-crank linkage
        mjTRN_TENDON,                   // force on tendon
        mjTRN_SITE,                     // force on site
-
+       mjTRN_BODY,                     // force on body
+       
        mjTRN_UNDEFINED     = 1000      // undefined transmission type
    } mjtTrn;