External obliques/obliquesOrigin: Lower 8 ribsInsertion: Iliac crestFunction: Flexes and rotates vertebral columnFlexion Rotation ExtensionDumbbell side bend stretches thismuscle.Side jackknife strengthens.
Gastrocnemius/Calf muscleOrigin: Distal femurInsertion: CalcaneousFunction: Plantar flexes foot and flexes kneePlantar flexion Flexion InversionWork out on exercise bike tostrengthen.Bend front knee, stretch out backleg and put wait on front to stretchmuscle.
Biceps brachii/BicepsOrigin: Scapula of shoulder girdleInsertion: Proximal radiusFunction: Flexes elbow and supinates forearm.Flexion Supination ExtensionUse dumbbells to strengthen.Position the arm against a wall and turn body away tostretch.
Latissimus dorsi/LatsOrigin: Lower spine and iliac crestInsertion: Proximal humerusFunction: Extends and adducts humerusExtension Adduction FlexionPull-ups strengthen this muscle.Overhead lat stretches this muscle.
Triceps brachii/TricepsOrigin: Shoulder girdle and proximal humerusInsertion: Olecranon process of ulnaFunction: Extends elbowExtension Flexion FlexionPull arm over head and bend elbow tostretch.Push-ups strengthen.