Supermaximal eccentric training (SET) is a training method that uses loads greater than maximum concentric loads (over 100% 1RM) in order to achieve specific adaptations in the muscles and nervous system.

Ovaj pristup dovodi do znacajnih promena na nivou misicnih vlakana, fascikula i hormona, sto zajedno poboljsava snagu, hipertrofiju i oporavak misica.

1. Titin Protein and the Physiological Basis of Contraction

Titin is the largest known protein in the human body and is key to the structural integrity and elasticity of muscles. Connects myosin (thick filaments) to Z-discs in sarcomeres, the basic units of muscle contraction, providing passive elasticity and stability during muscle contraction and stretch.
During eccentric contractions, when the muscle is stretched under load, titin stretches and stores elastic energy. This energy is released during the concentric phase, contributing to the efficiency of muscle function. Increased loading during SET can cause adaptations in titin, leading to greater resistance to stretching and improved muscle function.

2. Adaptations of Muscle Fibers and Fascicles

SET causes specific adaptations in muscle fibers:

• Increasing fascicle length: Eccentric training can lead to serial sarcomere hyperplasia, which lengthens fascicles and improves the muscle’s ability to generate force at higher shortening speeds.
• Changes in the type of muscle fibers: There may be a transition from slow (type I) to fast (type IIa) fibers, which increases the potential for force and power production.

3. Recovery Time after SET

Due to the high mechanical stress, SET requires a long recovery time:

• Microtraumas of muscle fibers: SET causes more microdamages, which requires a longer period for repair and adaptation.
• Recovery of the nervous system: The high intensity of SET can lead to fatigue of the central nervous system, which requires adequate rest for full recovery.

4. Optimal Application of SET

SET is most effective when used as an adjunct to a standard strength training program:

• Frequency: 1-2 times a week per muscle group.
• Volume: Limited number of sets (2-4) with fewer repetitions (3-5) due to high intensity.
• Periodization: Include SET in training phases focused on developing maximal strength or hypertrophy, with an adequate recovery period.

5. Difference between Fast and Slow Muscle Fibers

Muscle fibers are divided into:

• Pro-contracting (type I): They have a high resistance to fatigue and are used mainly for endurance activities.
• Fast-twitch (type IIa and IIb): They have a greater ability to produce force and power, but are less resistant to fatigue.

SET specifically activates fast-twitch muscle fibers due to the high intensity and eccentric nature of the contraction, which can lead to their growth and increased strength.

6. Hormonal Role and Effects in Regeneration after SET (48-72h)

Hormonski odgovor na SET igra kljucnu ulogu u procesu oporavka i adaptacije misica:

• Testosterone: Increases protein synthesis and accelerates the recovery of damaged muscle fibers. Its level rises during and immediately after SET, with a peak 30-60 minutes after training, and remains elevated for up to 24 hours.
• IGF-1 (Insulin-like growth factor): Activates the mTOR pathway, key to muscle synthesis, and plays an important role in the regeneration of satellite cells that repair damaged muscle fibers.
• Cortisol: A catabolic hormone that increases during SET due to high mechanical stress. The maximum growth is recorded 30-60 minutes after training, and decreases in the next 24-48 hours.Kortizol: Katabolicki hormon koji se povecava tokom SET-a zbog visokog mehanickog stresa. Maksimalan rast se belezi 30-60 minuta nakon treninga, a opada u narednih 24-48 sati.
• Growth hormone (GH): Increases the synthesis of collagen, which is crucial for the recovery of muscles and tendons. The biggest increase occurs during sleep on the first night after training. It maintains increased lipid oxidation, which contributes to the recovery of energy reserves.
• Myokines (IL-6, IL-15, BDNF):
• IL-6: Activates anti-inflammatory processes and helps repair muscle tissue.
• IL-15: Directly influences muscle fiber hypertrophy.
• BDNF: Improves neuromuscular connectivity and adaptations of the nervous system.

7. Microcycle with two SET exposures

This microcycle is designed for athletes who want to improve maximal strength, hypertrophy and eccentric muscle endurance.