EFFECTS OF HIIT, LISS, AND PHA ON BODY COMPOSITION: THE ROLE OF STANDARDIZED MEASUREMENTS AND SUBJECTIVE PERCEPTIONS IN HEALTH PROMOTION

Abstract

High-Intensity Interval Training (HIIT), Peripheral Heart Action (PHA) training, and Low-Intensity Steady-State (LISS) exercise are among the most commonly adopted exercise models in health-oriented fitness and personal training settings. Although each modality has demonstrated beneficial effects on body composition and well-being, evidence integrating anthropometric and psychophysical adaptations across these approaches remains limited, particularly when standardized assessment procedures are employed. This study aimed to provide an integrated comparative analysis of anthropometric and psychophysical adaptations observed across three pilot interventions involving HIIT, PHA, and LISS conducted under comparable real-world personal training conditions. An integrated secondary analysis was performed on three quasi-experimental pilot studies involving physically active adults who completed supervised 12-week exercise interventions. All protocols were performed three times per week and monitored through heart rate control. Anthropometric outcomes were assessed using standardized International Society for the Advancement of Kinanthropometry (ISAK) procedures and included body mass, body mass index (BMI), circumferences, skinfold thicknesses, adipose mass, muscle mass, and somatotype components. Subjective perceptions of psychophysical well-being and perceived performance improvements were also examined. Findings from the three studies were comparatively integrated and interpreted. All exercise modalities produced significant improvements in body composition. Significant reductions in body mass, BMI, waist circumference, adipose mass, and endomorphy were observed within groups (all p < 0.05).