Arnold Schwarzenegger – actor, politician, and former bodybuilding world champion – has proven that with hard work and the right strategy, one can achieve seemingly impossible things.
Not only pumping in the gym gets you closer to your fitness goals. It is also the smart combination of strength and endurance training. But how does one manage to unite both trainings while maximizing the health benefits of the workouts? We investigate this question as we unlock the secret of effective training.

Essentially, there are several points to consider when combining strength and endurance training. Strength training refers to exercises aimed at strengthening the musculaturethe entirety of all muscles in the body, while endurance training aims to improve cardiovascular fitnessthe health of the cardiovascular system. Together, they form what is known as "concurrent training" ^[1], which promotes both physical strength and endurance. A proven approach in this regard is High-Intensity Interval Training (HIIT)a form of training that alternates short, intense exertions with breaks. It can deliver astonishing results when practiced correctly.

The health impacts of a well-executed combined training program are comprehensive. Studies show that incorporating HIIT into weekly training can increase aerobic capacitythe body's ability to utilize oxygen efficiently while also improving muscle strengththe ability of a muscle to generate force ^[2]. This means that one can not only lift heavier weights but also run or cycle longer and more efficiently. But that’s not all: Stronger musculature and a better-functioning cardiovascular system significantly contribute to overall health, reduce the risk of cardiovascular diseases, and promote well-being. In addition, the time needed for regeneration is shorter.

One of the most relevant studies on our topic examined the effects of HIIT on muscle endurancethe ability to perform a movement over an extended period and sympathovagalthe balance between the sympathetic and vagus nerves that influences the autonomic nervous system adaptations ^[2]. This study included a medium-sized sample of 20 university students, who were studied during the pandemic-related lockdown. The study showed significant improvements in muscle endurancethe ability to perform a movement over an extended period and cardiac autonomic modulation after eight weeks of HIIT. Despite the limitations of the studydesign (online training during lockdowns), the study provides valuable insights into the effects of targeted HIIT application.

Another study involving 44 untrained, healthy individuals (averaging 27 years) examined the effects of protein supplementation after low-intensity combined training ^[1]. It showed that targeted protein supplementationintake of additional proteins to support muscle growth significantly promoted progress in muscle strength, especially in the leg muscles. These findings are particularly valuable as they highlight the relevance of adequate nutrition for proper training effects.

To optimally utilize the benefits of strength and endurance training, you should integrate two to three HIIT sessions per week into your training ^[2]. This is particularly comfortable, as HIIT sessions are often shorter than traditional training sessions, making them easier to fit into daily life. Also, ensure your body receives sufficient protein after training to achieve the best results ^[1]. This can be done through protein-rich foods like chicken breast, lentils, or quark.

Strength and endurance training should go hand in hand with each other. Talking about general fitness training: With the right combination of HIIT and targeted nutrition, you can efficiently and sustainably achieve your fitness goals.
The study results support the integration of HIIT sessions and the intake of adequate amounts of protein. Give it a try and experience how your strength and endurance develop together.