The effect of long-term high-intensity workouts improving physical fitness in adolescent males

Abstract

Background and Study Aim. The combination of a sedentary lifestyle with low physical activity contributes to reduced quality of life and can be a cause of death. Changing a sedentary lifestyle habit, such as increasing physical activity, is a form of prevention against the emergence of health problems. This study aimed to investigate the impact of long-term high-intensity workouts on enhancing physical fitness in adolescent males. Material and Methods. The study included 25 male adolescents aged 19-23 years who were university students residing in Malang. The participants were randomly assigned to one of two groups: K1 (control group; n = 12) or K2 (high-intensity workout group; n = 13). The high-intensity workout intervention was administered three times per week for eight weeks. Physical fitness components, including VO₂max, speed, agility, strength, and flexibility, were measured twice: before and after the intervention. The data were analyzed via an independent samples t-test with a 5% significance level. Results. Significant improvements in VO₂max, strength, speed, and agility were observed in the high-intensity workout group (K2), while no significant changes occurred in the control group (K1). Mean ∆VO₂max between K1 and K2 (0.13±0.56 to 4.49±1.18 mL/kg/min, p=0.001), ∆speed (-0.02±0.05 to -0.21±0.15 s, p=0.001), ∆agility (0.03±0.21 to -0.56±0.26 s, p=0.001), ∆strength (1.50±2.02 to 8.85±1.82 kg, p=0.001), and ∆flexibility (0.98±2.16 to 1.82±0.66 cm, p=0.219). Conclusions. This study revealed evidence of the effect of high-intensity workout interventions on improving physical fitness components but not on flexibility improvement, likely due to the strength- and endurance-focused nature of the training program.