A multitude of training protocols exist, aiming at strength gains and muscle hypertrophy. This paper is a critical review of the existing literature on this topic, and will examine the arguments in favor of isometric or isotonic protocols. Furthermore, the paper will contrast the physiological and mechanical adaptations caused by each training method, and describe advantages and disadvantages of each. Finally, the relative risk of injury for each method must be considered to ensure the safety of participants.

The foundation of this question dates as far back as the ancient Olympic Games, where organized athletic competition found its roots (Perseus, 2004). Since the origin of sport, athletes have sought competitive strategies for improving odds at victory. Though only a hundred years ago, weight training was reserved for "circus strongmen," these performers helped modernize competitive strategies with resistance training (Reeves, Laskowski & Smith, 1998). Organized practice of these strategies eventually created the fitness industry, which now generates over $6 billion annually in the U.S., and the search for the safest and most effective training protocol contributes largely to that figure (Kratzman & Stamford, 2002). Though the literature existing on the subject is now exceedingly vast, the results are often contradictory.