The extrinsic muscles are the long flexors and extensors. The extrinsic muscle groups are the long flexors and extensors. Stretching the flexors and extensors is helpful, as are strengthening exercises. Tendons are classified as flexors (flex a joint) or extensors (extend a joint). The extensors generally belong to the anterior compartment and the flexors to the posterior. Generally, the extensors lie on anterior of the thigh and flexors lie on the posterior. Triceps is the major extensor and brachialis and biceps the major flexors. They help to develop the hip flexors, abdominal muscles and leg muscles. The extensor muscles are inhibited to prevent competition between the extensor and flexors. Below its tendon, the tendons of the long flexors pass through the tarsal canal. A prone grip will rely more greatly on the other flexors, the brachialis and brachioradialis. Additionally, the interossei act as plantar flexors at the metatarsophalangeal joints. The fingers have two long flexors, located on the underside of the forearm. At this point the hip extends and the hip flexors are elongated. Strengthening exercises for the hip flexors may also be an appropriate component of the program.