Effects of Isometric and Isotonic Training on Health-Related Fitness Components in Young Adults

Abstract

Isometric and isotonic exercises are important modes of resistance training for enhancement of athletic performance. However, less is known about their effects on fitness and health in recreationally physically active individuals. This study evaluates the effect of isometric and isotonic training protocols on health-related fitness components in young university students. A group of one hundred males (18–24 years) underwent a 12-week isotonic and isometric training program (two days per week, 45 min per session). They were randomized into two groups, group A (n = 50) and group B (n = 50). While group A underwent the isotonic resistance training, the group B completed isometric resistance training. Prior to and after training programs, body mass index (BMI) was measured and the bench press 1RM test, sit-ups test, sit and reach test, and 12 min run/walk test were performed. Results showed significant improvements in BMI, bench press 1RM test, sit-ups test, sit and reach test, and 12 min run/walk test after both isotonic and isometric training protocols. The isotonic training group increased in BMI by 2.70%, bench press 1RM by 34.45%, number of sit-ups by 24.13%, sit and reach distance by 29.12%, and 12 min run/walk distance by 19.82%. Isometric training group increased in BMI by 1.96%, bench press 1RM by 14.23%, number of sit-ups by 7.80%, sit and reach distance by 6.92%, and 12 min run/walk distance by 6.99%. A comparison of these training protocols revealed that the isotonic group improved significantly more than the isometric group in the bench press 1RM (20.22%), number of sit-ups (16.33%), and sit and reach distance (22.2%) but not in the 12 min run/walk distance (12.83%) and BMI (0.74%). These findings indicate that both isotonic and isometric resistance training protocols improve health-related fitness components in young adults; however isotonic training is more efficient than isometric training in increasing their muscle strength, muscular endurance, and flexibility.