An essential consideration in forming an effective physical training program is the adaptive response of the muscular system.
Attaining an ideal, personalized physical training program requires considering factors such as overload, specificity and individual differences. The objective of physical training is to promote increased muscle growth (hypertrophy).
Conversely, deficiency of strength, defined as atrophy, develops when muscles are not strengthened to their capacities. Thus, to achieve effectiveness in an exercise program, specific muscular units must be targeted.
Specificity of a physical conditioning program is also imperative because it conditions athletes for certain sports or activities. For example, distance runners require endurance and a program designed to target muscle groups (namely slow-twitch muscles) that strengthen these endurance-building muscular units. Weight lifters and athletes seeking energy bursts develop quickly contracting muscles (fast-twitch muscles).
Increasing the strength and size of muscles requires applying the principle of overload.
Overload, using tension to contract muscles close to their maximum, improves muscle strength. Overload necessitates resistance increases in order to witness consistent strength gains.
Nevertheless, since increased resistance is only safe in certain limits before the body is injury-prone, periodization is important. Periodization is a method that episodically changes physical training in terms of intensity and the areas of the body exercised.
Also, a necessary component of gaining muscle strength is rest. Rest is as crucial as the strength training itself because muscles gain their greatest force from rest periods.
There should be rest spaces between exercises and in the resistance training program itself. According to The California State University, athletes should ideally strength train three to four times a week with squats, bench press, and pull ups, allowing proper rest intervals between large muscle group exercises.
Specificity of a physical program entails strengthening certain motor units or muscle groups. The muscles exercised consequently gain strength.
For instance, if shoulder muscles are exercised, hypertrophy occurs in these muscles rather than other muscle groups (such as leg muscles). Correspondingly, an individual should take into account their desired end, whether short-term strength or long-term endurance.
Slow-twitch muscles are less given to fatigue, but have a lower magnitude of sheer strength capacity than fast-twitch muscles. High-repetition, low-intensity training strengthens these muscles in particular. Distance runners and endurance athletes favor a training program that takes this into account.
Low-repetition, high-intensity training is primarily reserved for sprinting and high energy activities. This type of resistance training promotes quick contracting of fast twitch muscle fibers.
Another component of specificity involves exercises that mirror desired movements. For example, in the case of rowers, they must train the muscular units exercised in rowing.
Genetics determine muscle fiber composition and predominance of either fast- or slow-twitch muscle fibers. Nevertheless, with an effective training program, compensation for deficiencies can be achieved.
Ultimately, adaptation to exercise is largely influenced by overload, specificity and genetics. These factors are crucial in understanding the body's response to resistance training and the adaptations that occur.
Christy Druffel received her bachelor of science degree from Oregon State University in exercise sport science and fitness program management She has been working for the YMCA for the last 15 years and is the Director of Healthy Living.