Effects of Traditional Resistance Training and Combined Low-Load Blood Flow Restriction Training on Knee Extensor Strength and Thigh Circumference in Adult Men

OBJECTIVES The purpose of this study was to compare the effects of a traditional high-load resistance training program with those of a combined training program consisting of high-load resistance training plus additional low-load blood flow restriction (BFR) exercise on knee extensor maximal strength and thigh circumference in adult men.METHODS Twenty-four healthy adult men were randomly assigned to either a traditional resistance training group (n = 12) or a combined BFR training group (n = 12). Both groups participated in a supervised training program twice per week for 10 weeks. Knee extensor maximal strength (60°/sec) and thigh circumference were measured before and after the intervention. A two-way mixed ANOVA was conducted to examine the effects of group and time.RESULTS Both groups demonstrated significant increases in knee extensor maximal strength over time (<i>p</i> < 0.001), with no statistically significant group × time interactions observed for either limb (<i>p</i> > 0.05). For thigh circumference, significant group × time interactions were observed for both the right (F(1,22) = 4.876, <i>p</i> = 0.038, ηp² = 0.181) and left limbs (F(1,22) = 11.656, <i>p</i> = 0.002, ηp² = 0.346). The traditional resistance training group showed greater absolute increases in thigh circumference than the combined BFR group (right: +1.62 vs. +0.61 cm; left: +1.75 vs. +0.75 cm).CONCLUSIONS Both training strategies were associated with improvements in knee extensor strength, with no statistically significant between-group differences detected. The traditional resistance training group demonstrated greater increases in thigh circumference; however, these findings should be interpreted cautiously because circumference is an indirect measure of morphological change. These results suggest the potential practical applicability of combined BFR training, although further research is required.