Could different load reduction resistance training schemes lead changes on serum vascular endothelial growth factor?

BACKGROUND: We sought to examine the impact of load reduction strategies (LRS) during resistance exercise on serum vascular endothelial growth factor (VEGF) levels. METHODS: Ten resistance-trained men (25.1 +/- 5.4 years, 76.1 +/- 8.4 kg, 175 +/- 10 cm) completed 3 bouts of resistance exercise in a randomized, counter-balanced order. Bouts consisted Of six exercises completed for four sets of repetitions to failure (RTF). Intensity varied as follows: CON (constant load for each exercise for all 4 sets of 10 RM), RED5 (reduced by 5% for each successive set [i.e. 100%, 95%, 90% and 85% of 10RM]), and RED10 (reduced by 10%). Blood was obtained pre-exercise (PRE), postexercise (POST), and at 30 min recovery (REC) for determination of VEGF. Total repetitions performed and volume load (kg) lifted for each bout were calculated. Data were analyzed using repeated measures ANOVA. Statistical significance was set at the P <= 0.05 level of confidence. RESULTS: Both LRS increased the total # of reps performed (P <= 0.003), while only RED10 increased volume load above CON (P<0.001). VEGF significantly fluctuated over time (time effect P=0.007) and there was a significant condition x time interaction (P=0.010). Post-hoc comparisons found no differences among conditions x time, with only the REC RED10 vs. the PRE CON nearing the threshold for significance (+17%; P=0.054). CONCLUSIONS: Load reduction strategies can significantly increase the amount of work performed during resistance exercise when sets are performed RTF. LRS can evoke mild changes in serum VEGF concentrations, with a tendency towards increasing serum VEGF during the recovery period after exercise in comparison with a constant load.