Weight training exercises are often an important part of physical rehabilitation. Explore these resources for using weights in injury and illness recovery. Think of weights, resistance or strength training, and ‘muscle’ often comes to mind. Although you can get stronger with resistance training without necessarily growing big muscles, the fact is that muscle, in conjunction with the nervous system, is modified in various ways to make you bigger or stronger, and often both. But what is muscle and how does it function? The building blocks of muscle are muscle cells. A ‘cell’ is a fundamental unit of body tissue and organs. Blood cells, brain cells, hair cells, bone cells, and many other types of cells make up the human body. Muscle is served by a blood supply and nerves. Both are involved in the outcomes of weight and resistance training. At the heart of this process is work done. When muscles work under the stress of weight lifting as you work out, muscle fibers suffer microscopic damage. When you re-fuel, eat and rest, that muscle is repaired and made stronger, and often larger. For bodybuilders and general exercisers looking for the lean and muscular look, this is the enduring process. For Olympic lifters and Powerlifters and other strength and power athletes, lifting heavy weights primes the nervous system. A ‘motor unit’ is a muscle complex consisting of a nerve cell (neuron) and the muscle it stimulates. Lifting heavy weights (rather than lighter weights), stimulates motor units and prepares you to be able to lift heavier weights in a type of feedback system. The bottom line is that if you want to get stronger, rather than more muscular, you need to practice lifting closer to the maximum you can lift for any particular exercise.Not only does heavy and high-intensity lifting stimulate strength and muscle according to the mechanisms described above, but placing the muscle under stress also stimulates human growth hormone and the male hormone testosterone — anabolic hormones that deliver strength and muscle to the body through biochemistry. So the ideal training range of sets and reps for the development of combined strength and muscle is likely to be in the range of 3-5 sets of 5-10 repetitions, with rest between sets of 1-2 minutes, and utilizing weights at between 75-90% of 1RM. Strength training is all the rage these days. Where the aerobics of the 80s are still in play, they have been diminished in popularity by the workouts that promise to tighten, tone, and yes, strengthen muscles. The sculpted, tone, athletic body seems to be the goal at present and workouts have been refined to meet this growing demand. Aside from the desire to have the ultimate fit and toned body is a very real need for the kind of physical exercise required to recover from injury or surgery. Physical therapy offers specifically tailored exercise designed to strengthen and facilitate the body’s repair of muscle tissue. Patients are challenged to reach beyond their comfort zone in these instances. Without doing so, they will not meet the goal of fully recovering from injury or surgery. As a take away after physical therapy, patients are often encouraged to use strength training workouts to continue their recovery and increase their overall fitness.