IGF-I, IGFBPs, and inflammatory cytokine responses during gender-integrated Israeli Army basic combat training

Area of Science:

• Exercise Physiology
• Endocrinology
• Sports Science

Background:

• Insulin-like growth factor 1 (IGF-I) is a key biomarker for metabolic and anabolic changes due to physical training.
• Understanding the IGF-I system, including insulin-like growth factor-binding proteins (IGFBPs) and inflammatory cytokines, provides deeper insight into training adaptations.
• Sex and initial fitness levels are potential modulators of these physiological responses.

Purpose of the Study:

• To investigate the influence of sex and initial aerobic fitness on IGF-I, IGFBP, and inflammatory cytokine responses during gender-integrated Israeli Defense Forces (IDF) basic combat training (BCT).

Main Methods:

• Recruited 29 men and 93 women from a 4-month IDF BCT program.
• Assayed blood for total IGF-I, free IGF-I, IGFBPs 1-6, TNF-α, IL-6, and IL-1β pre- and post-training.
• Measured body composition and maximal oxygen consumption (V̇O₂max) to assess physical performance and training adaptations.

Main Results:

• Significant time effects were observed for total IGF-I, IGFBP-2, TNF-α, V̇O₂max, fat-free mass, and fat mass.
• Men and women exhibited similar responses in blood markers and V̇O₂max.
• Initial fitness level modulated the IGF-I response to training exclusively in women.

Conclusions:

• Gender-integrated military BCT generally elicits similar IGF-I system and inflammatory cytokine responses in men and women.
• While training induced favorable anabolic changes (increased IGF-I, decreased IGFBP-2 and TNF-α), only men demonstrated correlations between IGF-I changes and improvements in body composition and fitness.