Should You Train Close To Failure?

Well, that depends on your training goal and your training experience. If you are eager to build fat free mass and tone up your physique, then most likely the answer is Yes, because approaching failure guarantees a high level of muscle fiber recruitment, especially of the type II fibers, which are vital for muscle growth.

According to Henneman's size principle, motor units are engaged in a systematic manner (Henneman et al., 1965). This principle states that as the demands for force production rise, motor units are activated based on their force output capacity, starting with the smaller motor units (Sale, 1987). Theoretically, during a resistance training session utilizing moderate weights, the lower threshold motor units linked to type I muscle fibers are the first to be activated to lift the weight.

As these lower threshold motor units experience fatigue, there is increased recruitment of the higher threshold motor units related to type II muscle fibers to sustain force output. Therefore, executing resistance exercise sets close to the point of momentary muscular failure (a state of physical exhaustion where the lifter cannot complete the concentric phase of a repetition, despite making an earnest effort to do so (Lasevicius et al., 2019)) is believed to be essential for recruiting all available motor units (Fisher & Steele, 2013).

How close to failure should you train?

Before talking about that, we need to understand the concept of RPE (Rating of Perceived Exertion), is a subjective scale that allows individuals to gauge their effort during exercise, while RIR (Reps in Reserve), quantifies how many more repetitions one could perform before reaching failure. An RIR-based RPE scale assigns a numerical value to the perceived number of repetitions left in reserve, where an RPE of 10 corresponds to 0 RIR, indicating no more repetitions can be performed, while an RPE of 7 suggests that there are about 3 repetitions left in reserve (Table 1) (Zourdos et al., 2016). Most experts agree that one to three repetitions before reaching failure is ideal.

Table 1 Resistance training-specific RIR-based RPE scale
RPE Score	RIR/Description
10	Maximal effort
9.5	No RIR, but could increase load
9	1 RIR
8.5	Definitely 1RIR, maybe 2 RIR
8	2 RIR
7.5	Definitely 2 RIR, maybe 3 RIR
7	3 RIR
5~6	4~5 RIR
3~4	Light effort
1~2	Little to no effort

 

Adapted from Zourdos et al. 2016

RPE = Rating of Perceived Exertion ; RIR = Repetitions in Reserve

 

References

Fisher, J., & Steele, J. (2013). EVIDENCE-BASED RESISTANCE TRAINING RECOMMENDATIONS FOR MUSCULAR HYPERTROPHY. Medicina Sportiva, 17(4), 217–235. http://dx.doi.org/10.5604/17342260.1081302

Henneman, E., Somjen, G., & Carpenter, D. O. (1965). FUNCTIONAL SIGNIFICANCE OF CELL SIZE IN SPINAL MOTONEURONS. Journal of Neurophysiology, 28(3), 560–580. https://doi.org/10.1152/jn.1965.28.3.560

Lasevicius, T., Schoenfeld, B. J., Silva-Batista, C., De Souza Barros, T., Aihara, A. Y., Brendon, H., Longo, A. R., Tricoli, V., De Almeida Peres, B., & Teixeira, E. L. (2019). Muscle failure promotes greater muscle hypertrophy in Low-Load but not in High-Load resistance training. The Journal of Strength and Conditioning Research, 36(2), 346–351. https://doi.org/10.1519/jsc.0000000000003454

Sale D. G. (1987). Influence of exercise and training on motor unit activation. Exercise and sport sciences reviews, 15, 95–151.

Zourdos, M. C., Klemp, A., Dolan, C., Quiles, J. M., Schau, K. A., Jo, E., Helms, E., Esgro, B., Duncan, S., Merino, S. G., & Blanco, R. (2016). Novel Resistance Training–Specific Rating of Perceived exertion Scale Measuring repetitions in reserve. The Journal of Strength and Conditioning Research, 30(1), 267–275. https://doi.org/10.1519/jsc.0000000000001049

- Written by: Coach Marcus