Background and Purpose: Superset training, as a time-efficient method, induces higher metabolic stress compared to traditional resistance training. However, the acute hormonal responses to these two methods in trained young men have not been fully elucidated. The aim of the present study was to compare the effect of a single session of traditional and superset resistance training on serum levels of IGF-1a and testosterone in trained young men.

Materials and Methods: Twelve trained young men (mean age 27.91 ± 4.9 years, body mass index 28.49 ± 2.46 kg/m²) participated in a quasi-experimental study with a cross-over design. Each participant experienced three experimental conditions (traditional resistance training, superset training, and control) with a one-week interval between sessions. Both training protocols consisted of 4 sets of 8-10 repetitions at an intensity of 80-85% of one repetition maximum. Blood samples were collected at three time points (baseline, immediately post-exercise, and one-hour post-exercise). Serum concentrations of IGF-1a and testosterone were measured using ELISA. Data were analyzed using repeated measures ANOVA and Bonferroni post-hoc test at a significance level of 0.05.

Results: The results showed that the main effect of time, the main effect of group, and the time × group interaction effect were significant for both IGF-1a and testosterone (P = 0.001). In both training groups, IGF-1a decreased immediately post-exercise (574.7 ± 1.93 and 369.0 ± 9.30 pg/ml, respectively, P = 0.001) and then increased at one-hour post-exercise (475.3 ± 4.58 and 205.7 ± 4.19 pg/ml, respectively, P = 0.001). The decrease in IGF-1a was significantly greater in the superset group compared to the traditional group (P = 0.001). Testosterone increased immediately post-exercise in both training groups (superset: from 0.804 ± 0.023 to 3.879 ± 0.056 ng/ml; traditional: from 0.870 ± 0.180 to 3.154 ± 0.069 ng/ml, P = 0.001), and this increase was significantly greater in the superset group (P = 0.001). At one-hour post-exercise, testosterone decreased but remained significantly higher than baseline levels (P = 0.001). No significant changes were observed in the control group (P > 0.05).

Conclusion: A single session of acute resistance training, regardless of the protocol type, is a strong stimulus for increasing anabolic hormone levels in trained young men. However, superset training, due to inducing higher metabolic stress, causes a greater decrease in IGF-1a (indicating stronger temporary suppression of the GH-IGF-1 axis) and a greater increase in testosterone compared to traditional training. Given the acute study design and limited sample size, these findings reflect only short-term hormonal differences and do not provide conclusive evidence that superset training is superior for muscle hypertrophy or long-term adaptations. Further longitudinal studies with larger samples are needed to confirm these results.