Improving muscle size with Weider’s principle of progressive overload in non-performance athletes

Abstract Introduction The concept of progressive overload is one of the most well known and well understood principles in strength training around athletes. To gain muscle mass, this principle consists of progress in weight, number of repetitions, frequency and sets. Aim Although it is a widely used principle, trough our study, we wanted to ascertain if, after training sessions applying Weider’s principle of progressive loading (PPO), we can highlight significant increases in some muscle groups (chest Mc, and back Mb ), in non-performance subjects. Materials and methods One sample (N= 8 subjects, 8 men, with a mean age of 20.4 ± 0.74 years), trained for 12 weeks with a frequency of 4 workouts per week, in a sports center from Arad county. Muscle perimeters were measured using a metric band. Subjects underwent bodybuilding-specific training with a predominant focus on PPO. Measurements of the pectoral muscle (Mc) and back muscle (Mb) were carried out in two stages: an initial test (Ci, Bi ) and a final test (Cf, Bf), to see at the end of the experiment, if there are improvements. Results After 12 weeks of training, the final results indicate an increase of the average of both chest and back muscles (Ci 102.6, Cf 107.4 and Bi 109.6, Bf 113.8). Although the values of the T-test, at both groups, are identical, it seems that the PPO effective size (ω2) is larger in the back (14%) compared to the chest (12%). Conclusion Within the limits of our experiment, we consider that by only using the PPO, significant improvements can be obtained on the targeted muscle groups.