Hormonal Responses to Heavy Resistance Training in Soccer Players: Driving Response to Injury Prevention

Hormonal responses to resistance training play a vital role in tissue repair, muscle hypertrophy, and adaptation to athletic stress. Testosterone (T), cortisol (C), growth hormone (GH), and insulin-like growth factor-1 (IGF-1) are among the key hormonal regulators influenced by heavy resistance training (HRT). Despite the widespread application of HRT in soccer performance programs, the underlying hormonal mechanisms remain underexplored—particularly in youth athletes.

Heavy resistance training (HRT) supports these physical demands by enhancing strength and neuromuscular efficiency. While improvements in performance metrics are often observable, the hormonal mechanisms driving these adaptations deserve further attention.

Heavy resistance training is defined as lifting loads equal to or greater than 80% of 1RM. This generally corresponds to 1–6 repetitions per set (NSCA, 2016; ACSM, 2002; Schoenfeld & Grgic, 2021). These intensities are optimal for neural recruitment and force production, distinguishing them from moderate-load hypertrophy training typically performed in the 6–12RM range.

Testosterone plays a pivotal role in muscle protein synthesis, neuromuscular activation, and post-training recovery. Acute elevations in testosterone have been consistently observed following HRT protocols using compound movements (e.g., squats, trap bar deadlifts). Kraemer et al. (1990) demonstrated significant post-exercise T elevations when athletes performed 5x5 at 85–90% 1RM. The hormonal response was influenced by rest intervals, volume, and the muscle mass involved.

Another reason we choose trap bar deadlifts…

Cortisol, a glucocorticoid released in response to training stress, also rises acutely following HRT—particularly under high volume and minimal rest conditions. While acute elevations support energy mobilization, chronically elevated cortisol may interfere with recovery and performance. Rosa et al. (2015) found that high-rep, forced-rep protocols significantly increased cortisol compared to submaximal training.

Not very optimal when practice and games already provide high C levels.

Now on to Growth Hormones…

GH and IGF-1 are crucial for connective tissue health and muscular remodeling. GH is particularly sensitive to high-lactate environments and short-rest intervals.

Goto et al. (2005) showed that GH increased significantly following short-rest HRT protocols, while IGF-1 was more responsive to nutritional status and recovery. Bemben et al. (2005) further highlighted the role of post-training protein intake in supporting IGF-1 activity.

While acute hormone spikes are well-documented, chronic hormonal adaptations are less pronounced. Long-term HRT does not consistently raise resting T or GH. Instead, adaptations include increased sensitivity of tissues to hormonal signals and improved neuromuscular efficiency.

Heavy Resistance Training leads to reduced injury risk and increases return to play when injury occurs.

Brunsden et al. (2017) emphasized that strength gains were more closely tied to mechanical tension and intracellular signaling (e.g., mTOR pathway) than to acute hormone elevations. West and Phillips (2012) similarly concluded that muscle growth depends more on local muscular signaling and protein intake than transient systemic hormone levels.

Again why mechanical tension is needed in conjunction with Plyometrics…

Enough of the “fascia only “ training…

Competition matters for hormonal health…

Winners vs losers has a direct impact to hormonal response.

Testosterone and cortisol levels are also influenced by psychological arousal—especially during competitive play. Jiménez et al. (2016) observed significantly elevated testosterone in soccer players before and after official matches compared to training sessions. This response is amplified by factors such as match importance, starting status, and outcome.

The Challenge Hypothesis suggests testosterone surges during dominance contests (Wingfield et al., 1990), while the Dual-Hormone Hypothesis proposes that the behavioral effects of testosterone are modulated by cortisol levels (Mehta & Prasad, 2015). Salvador et al. (2001) reported that judo athletes with higher pre-match T and lower C performed better and displayed greater motivation to win.

The hormonal responses to heavy resistance training provide essential insights into how athletes adapt to physical and psychological stress. While acute increases in testosterone, cortisol, and GH are well-documented following intense strength sessions, long-term adaptations are more nuanced and influenced by training quality, recovery, and age.

Youth soccer players respond differently due to their developmental stage but can still benefit from well-structured resistance programs.

Incorporating endocrine considerations into a broader performance model enhances the precision and effectiveness of both youth and elite-level training interventions.

This is another example of how we separate ourselves from the competitors. We take a layered approach to your athletes development, training frequency and volume.

Exercise selection as well as a thoughtful approach to training is essential to improve in a long term development environment.

References

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