multiple types of exercises with different grips: The main handles are the two hold points which taper out toward the end of the bag and are used for swinging and spinning motions. The exterior handles are three tube-like protrusions wrapped in goat skin that sit on the outer top of the bag; the center handle is set between the two outer handles. The exterior handles are primarily used for grip strength and upper body exercises. The third elements are called 'straps' and are two looped nylon straps sewn directly to the bag’s exterior. They are approximately 12 inches long and are used to stabilize the bag on the shoulders during lower body workouts, and as grasping handles for arm exercises. Self-made Bulgarian Bags can be constructed out of automobile inner-tubes or children's ring float toys. Variations Depending on a person's size and level of physical fitness, Bulgarian Bags are manufactured in different sizes and weights: Use The bag can be used as a free weight in various simple and dynamic movements like pushing, spinning, swinging and rotating, and added to one's body weight to perform jumps, squats, push-ups, pull-ups and power crunches. Many sample workout routines have been posted on the Internet. Fitness advantages The Bulgarian Bag strengthens and increases the muscular endurance of the grip, wrists, arms, shoulders, back, legs, and rotational muscles. It also aids in building core musculature, coordination, and improving overall shoulder and joint mobility. Because of its shape, material and construction, Bulgarian Bag can be used to develop quickness and agility in ways which solid iron weights and circuit machines cannot. Variable angular resistance The Bulgarian Bag breaks the tradition with static resistance devices such as free weights which adhere to a singular plane of motion (i.e. creating resistance by pushing or pulling weight away from and toward the body), by using accelerating and deceleration movements to swing and spin the bag at various angles to athlete's body. This results in the Bulgarian Bag’s ability to increase overall body strength and agility. The multi-angular approach to gravity, momentum and inertia in physical exercise has been termed Variable Angular Resistance training in some use. Aerobic effect After cardiovascular exercise or weight training, the body continues to need oxygen at a higher rate than before the exercise began. High intensity bouts of exercise with the Bulgarian Bag increase metabolic rates higher than traditional weight training and cardiovascular