Coratella, Giuseppe; Beato, Marco; Bertinato, Luciano; Milanese, Chiara; Venturelli, Massimo; Schena, Federico

Journal of Strength and Conditioning Research: November 2022 - Volume 36 - Issue 11 - p 3023-3031, doi: 10.1519/JSC.0000000000004039

PURPOSE:

To compare the effects of concentric-based (CONC), eccentric-based (ECC), and traditional concentric-eccentric (TRAD) resistance training on muscle strength, mass, and architecture and the post-detraining retention of the training-induced effects in women.

PROCEDURE:

Sixty women were randomly assigned to volume-equated groups (n = 15/group) @ CONC, ECC, TRAD knee extension training, or control.

For pre-training, during 8-weeks of training, and 8-week post-detraining measured were isokinetic concentric, eccentric, and isometric torque. Also, thigh lean mass was assessed by dual X-ray absorptiometry (DEXA) and vastus lateralis (thigh) thickness, pennation angle, and fascicle length were measured by ultrasound.

CONCLUSIONS:

After training, concentric and isometric torque increased similarly in all groups, whereas eccentric torque increased more in ECC (13.1%) than that in CONC (12.6%).

Thigh lean mass increased in ECC (+6.1%) vs. TRAD (+3.1%).

Vastus lateralis thickness and pennation angle increased similarly in all groups, whereas fascicle elongation was more visible in ECC (+9.7%) than in TRAD (+7.1%).

• 8-week post detraining showed:

• All groups retained similar concentric torque.

• ECC and TRAD preserved eccentric torque, but ECC did so more than TRAD.

• All groups preserved isometric torque, but ECC did so more than CONC and TRAD.

• Thigh lean mass and vastus lateralis fascicle length were retained only in ECC.

• Pennation angle was preserved in all groups.

• Thigh thickness was retained in CONC and ECC.

• Overall, emphasizing the eccentric phase in resistance training is essential to preserve adaptations after detraining.

Compared to traditional or concentric-based protocols, eccentric-based exercise allows for the use of supramaximal loads which can help retain both the muscle strength and structural training-induced adaptations.

Even though traditional resistance training protocol may provide a good overall maintenance of the strength adaptations, the inclusion of some sessions with an eccentric-based protocol may help to increase and better preserve the eccentric strength, useful for both sports' performance and daily life activities.

Also important is longer fascicles result in faster strength and power exertion, and its development and maintenance induced by eccentric-based protocols are important when fast actions are required and need to be preserved.

Finally, including the eccentric phase in resistance training seems to provide more beneficial hypertrophic effects and seems to be crucial not to lose the adaptations.

In summary, supramaximal loads seem critical to retain adaptations in eccentric strength and fascicle length that are lost with detraining after concentric and traditional training.

IN PLAIN ENGLISH:

Another argument for emphasizing the eccentric phase in resistance training, both:

1. During traditional concentric (raising) and eccentric (lowering) exercises.

2. Using eccentric-only training against supramaximal resistances (safely).