When young men lift weights regularly for 15 weeks, their body’s immediate hormone spike after each workout stays about the same—no matter how many times they do it. It’s like their body keeps reacting the same way every time, without getting used to it.

A 15-week RCT with young men (18–30 years) performing standardized resistance exercise sessions (e.g., 3x/week, 70–85% 1RM, 3–4 sets of 8–12 reps) with blood samples drawn immediately post-exercise at baseline, week 4, week 8, and week 15 to measure serum testosterone, growth hormone, and IGF-1 levels. Comparator: same protocol across all participants with no variation in training load or recovery. Primary outcome: change in peak post-exercise hormone concentrations over time.

A longitudinal study tracking the same group of young men (n≥30) over 15 weeks of supervised resistance training, with acute hormonal responses measured immediately after each session (e.g., 3x/week) using frequent blood sampling (e.g., pre- and post-exercise at 0, 15, 30, 60 min). Hormone levels (testosterone, GH, IGF-1) are averaged per week and analyzed for trend stability using linear mixed models. Comparator: within-subject changes over time.

A crossover study where young men perform two 15-week blocks of identical resistance training separated by a 4-week washout period. Acute hormonal responses are measured at the end of each block (week 15) under identical conditions. Comparator: hormone response at end of Block 1 vs. Block 2 to assess consistency across repeated exposure cycles.

A case series of 15–20 young men undergoing identical, standardized resistance training for 15 weeks, with acute hormonal responses measured post-exercise at weekly intervals. Data are aggregated to assess mean and variance of testosterone, GH, and IGF-1 spikes over time. Comparator: individual trajectories analyzed for deviation from stability (e.g., coefficient of variation <10% across weeks).

Analysis of archived data from prior resistance training studies involving young men, extracting post-exercise hormone measurements taken at multiple time points over ≥12 weeks. Only studies with standardized protocols and consistent sampling times are included. Comparator: temporal trends in hormone elevation across participants to determine if responses plateaued or declined.