The most commonly used AAS in medicine are testosterone and its various esters (but most commonly testosterone undecanoate , testosterone enanthate , testosterone cypionate , and testosterone propionate ),  nandrolone esters (most commonly nandrolone decanoate and nandrolone phenylpropionate ), stanozolol , and metandienone (methandrostenolone).  Others also available and used commonly but to a lesser extent include methyltestosterone , oxandrolone , mesterolone , and oxymetholone , as well as drostanolone propionate , metenolone (methylandrostenolone), and fluoxymesterone .  Dihydrotestosterone (DHT; androstanolone, stanolone) and its esters are also notable, although they are not widely used in medicine.  Boldenone undecylenate and trenbolone acetate are used in veterinary medicine . 
The strength training circuit (STC) produces a total-body training effect for the development of strength and mobility. (See Table 9-9.) A sequence combining a CL, a military movement drill, and kettlebell exercises works every muscle group with active recovery between stations of exercise. The STC is best conducted at platoon level. The STC may be laid out around a running track, field, or any area of adequate size, and with access to climbing bars and kettlebells. This paragraph provides a diagram of the STC, using a running track, climbing bars, and kettlebells. (See Figure 9-34.) Conduct preparation according to Chapter 7 after a walkthrough and brief explanation of the STC exercise stations. (See Table 9-10.) The circuit may be completed in three rotations. Soldiers spend 60 seconds at each station. The instructor controls exercise time using a stopwatch and uses a whistle or horn to signal a change of station. At the end of all circuit rotations, recovery is conducted according to instructions in Chapter 7.
Nicotine is an addictive stimulant found in cigarettes and other forms of tobacco. Tobacco smoke increases a user’s risk of cancer, emphysema, bronchial disorders, and cardiovascular disease. Smoking rates have decreased in the United States in recent years, yet the mortality rate associated with tobacco addiction is still staggering, with more than 480,000 premature deaths in the United States each year—about 1 in every 5 Tobacco use killed approximately 100 million people during the 20th century and, if current smoking trends continue, the cumulative death toll for this century is projected to reach 1 billion. 8 More information can be found at /drugs-abuse/tobacco-addiction-nicotine .