with the elbows straight. It is important to keep the body straight, the stomach in and butt down. Start with twenty seconds and wor k Nitro-XX up to sixty seconds sets if able. The next exercise is leg extensions. Ten of these are done by sitting on a leg extension machine. A tricep pushdown machine is used to complete ten reps of tricep pulldowns. http://www.healthcaresups.com/nitro-xx/