This study investigated changes in physical fitness, body composition, and blood lipid profile following 24 weeks of 3 volume-equated concurrent strength and endurance training protocols. Physically active, healthy male and female participants (aged 18-40 years) performed strength and endurance sessions on different days (DD; men, n = 21; women, n = 18) or in the same session with endurance preceding strength (ES; men, n = 16; women, n = 15) or vice versa (SE; men, n = 18; women, n = 14). The training volume was matched in all groups. Maximal leg press strength (1-repetition maximum (1RM)) and endurance performance (maximal oxygen consumption during cycling), body composition (dual-energy X-ray absorptiometry), and blood lipids were measured. 1RM and maximal oxygen consumption increased in all groups in men (12%-17%, p < 0.001; and 7%-18%, p < 0.05-0.001, respectively) and women (13%-21%, p < 0.01-0.001; and 10%-25%, p < 0.01-0.001, respectively). Maximal oxygen consumption increased more in DD vs. ES and SE both in men (p = 0.003-0.008) and women (p = 0.008-0.009). Total body lean mass increased in all groups (3%-5%, p < 0.01-0.001). Only DD led to decreased total body fat (men, -14% ± 15%, p < 0.001; women, -13% ± 14%, p = 0.009) and abdominal-region fat (men, -18% ± 14%, p = 0.003; women, -17% ± 15%, p = 0.003). Changes in blood lipids were correlated with changes in abdominal-region fat in the entire group (r = 0.283, p = 0.005) and in DD (r = 0.550, p = 0.001). In conclusion, all modes resulted in increased physical fitness and lean mass, while only DD led to decreases in fat mass. Same-session SE and ES combined training is effective in improving physical fitness while volume-equated, but more frequent DD training may be more suitable for optimizing body composition and may be possibly useful in early prevention of cardiovascular and metabolic diseases.
Keywords: aerobic training; combined training; entraînement aérobie; entraînement combiné; entraînement contre résistance; health; metabolic health; performance physique; physical performance; resistance training; santé; santé métabolique.