Human growth hormone (HGH) is a naturally occurring anabolic hormone in the body secreted by the pituitary gland at the base of the brain. HGH promotes tissues regeneration, cell reproduction and muscle protein synthesis (1). As a result, HGH plays a key role in muscle (and bone) building, particularly through puberty and after strength/resistance training. There are a number of strategies to maximize HGH production after strength training.
Strategies to increase HGH production after strength training:
- Moderate training volume (about 6 sets) at moderate to high intensity (%1RM)
- Elongated time under tension (6 seconds per rep is better than 2 seconds)
- Incorporating eccentric and concentric phases of exercises
- Large muscle mass involvement
How to strength train to increase GHG
HGH levels in the body increase in response to resistance exercise and strength training and will remain elevated compared to pre-exercise levels in response to most training protocols (2). However, following certain training parameters can optimize HGH secretion, and thus the training effect seen.
The Impact of Sets and Reps on HGH
Higher training volumes increases post-exercise HGH levels compared to lower training volumes. Training volume is calculated based on the interaction of the number of sets and reps performed in a training session. In a study by Wilk et al. in 2018, it was found that performing 6 sets of 3 back squats had a better impact on HGH levels than performing 3 sets or 12 sets. Performing 6 sets or 12 sets of 3 back squats led to the (statistically) same level of HGH production. However, 12 sets led to a greater stress response from the body, quantified by blood cortisol levels, which would negatively impact the positive effects of HGH secretion (3).
This study suggests that performing more volume than optimal causes the anabolic hormone peak associated with strength training to happen during the training session. As a result, there is an increase in catabolic hormones which will decrease the training effect compared to when optimal volume is performed (3). Therefore, in terms of an anabolic hormone response (HGH secretion), the most effective volume is close to 6 sets.
The Impact of Tempo on HGH Secretion
Tempo is the cadence that reps are performed at and is broken into the eccentric, concentric and pause phases. Time under tension is often considered the total time spent performing a set. For instance, a tempo of 3-1-1 for 6 reps would have a time under tension of 30 seconds per set (5 seconds multiplied by 6 repetitions).
Few studies have investigated the role of tempo on HGH secretion. One study (2) identified that a moderate tempo (3-0-3-0 – eccentric, pause, concentric, pause) resulted in greater post-exercise HGH levels than a fast tempo(1-0-1-0).
The high metabolic stress associated with slower movement tempos may result in local accumulation of anaerobic energy metabolites, like lactate. The pituitary gland may secrete greater levels of HGH in response (4).
Concentric vs. Eccentric Exercises for HGH Response
It has been well established that the HGH response to resistance training is greater after concentric reps compared to eccentric reps performed at the same absolute load (e.g., 100 kg) (5). However, this is likely because we are stronger eccentrically than concentrically. Therefore, performing it is easier to perform eccentric repetitions compared to concentric repetitions when the load is the same.
However, if our increased eccentric strength is accounted for then the HGH response is the same following eccentric-only and concentric-only training. Therefore, you could perform concentric-only exercise at a given load or perform eccentric-only exercise at the load plus about 20% to get the same HGH response (5). A typical repetition including both eccentric and concentric phases will also be beneficial.
References
1. Bidlingmaier M, Strasburger CJ. Growth Hormone. In: Thieme D, Hemmersbach P, editors. Doping in Sports. Berlin, Heidelberg: Springer Berlin Heidelberg; 2009. p. 187–200. [cited 2021 Nov 27 ] Available from: http://link.springer.com/10.1007/978-3-540-79088-4_8.
2. Wilk M, Tufano JJ, Zajac A. The Influence of Movement Tempo on Acute Neuromuscular, Hormonal, and Mechanical Responses to Resistance Exercise—A Mini Review. J Strength Cond Res. 2020;34(8):2369–83.
3. Wilk M, Petr M, Krzysztofik M, Zając A, Stastny P. Endocrine response to high intensity barbell squats performed with constant movement tempo and variable training volume. 2018;39(4):8.
4. Siebert DM, Rao AL. The Use and Abuse of Human Growth Hormone in Sports. Sports Health Multidiscip Approach. 2018;10(5):419–26.
5. Kraemer RR, Hollander DB, Reeves GV, et al. Similar hormonal responses to concentric and eccentric muscle actions using relative loading. Eur J Appl Physiol. 2006;96(5):551–7.