Eight Weeks of Resistance Training Supplemented with Beta-Alanine and Sodium Bicarbonate Increased Muscle...

Sodium bicarbonate (SB) and betaalanine (BA) can enhance high-intensity exercise performance. This study examined the effects of eight weeks of resistance training combined with these supplements on muscle cross-sectional area (CSA), serum myostatin and interleukin-15 concentration, and upper- and lower-body muscular strength and power. Twenty active males (age: 18-35) were divided into supplement (SUP) and placebo groups (PL; each group n=10). Participants undertook eight weeks of supervised resistance training, including 3 sessions × 3 sets × maximum repetitions at 70% of 1RM. Supplementations included 3-6 g/day BA and 4-6 g/day SB administered for 8 weeks. Exercise volume, calculated as the total number of repetitions completed in each session, increased to a greater extent following SUP (~29%) than PL (~13%) groups (P=0.014). Central segment of quadriceps CSA, measured using magnetic resonance imaging, demonstrated a greater increase following SUP compared to PL for both right ((~21%; pre to post: 452.47±55.98 to 548.21±73.92 mm³) vs. PL (~5%; 443.81±28.74 to 466.42±31.91 mm³)) and left ((~24%, 456.81±59.77 to 566.71±82.62 mm²) vs. PL (~9%; 438.12±41.54 and 479.06±49.91 mm³)) legs (all P<0.01). However, interleukin-15 concentrations decreased following both conditions (time effect: P<0.001). Also, no difference was observed between groups for the increased 1-RM squat, bench press, and countermovement jump (time effects: P<0.05). The results suggest that co-ingestion of BA and SB may enhance the central segment of the CSA in the quadriceps muscle, possibly by increasing exercise volume. This could be a potential approach in promoting muscle hypertrophy in athletic and clinical rehabilitation settings.