The main issue is body composition (see the body fat calculator for more). Calorie expenditure will vary depending on the ratio of body fat to muscle or lean mass. NOTE that as our bodies adapt to exercise and our body composition changes - so will the amount of Calories burned.
The definition of a throttle is a valve that controls the fluid flow. An example of a throttle is a car part that controls how fuel moves through the system. Throttle is defined as to control the speed of an engine or the flow of fuel in an engine, or to hold down or choke.
The throttle is typically a butterfly valve. In a fuel-injected engine, the throttle valve is placed on the entrance of the intake manifold, or housed in the throttle body. In a carbureted engine, it is found in the carburetor. When a throttle is wide open, the intake manifold is usually at ambient atmospheric pressure.