Fatigue and the Interference Effect on Hypertrophy Summary
It’s been well documented that fatigue influences muscle hypertrophy. Researchers conducted a study to understand the effects of different fatiguing protocols on performance. They divided the protocols into five groups: control group, upper-body high-fatigue (4 sets to failure during bench pull exercise), upper-body low-fatigue (4 sets of 6 repetitions during bench pull exercise), lower-body high-fatigue (4 sets to failure during leg-press exercise), and lower-body low-fatigue (4 sets of 6 repetitions during leg-press exercise). Interestingly, the main findings showed a decline in performance after high-fatigue RT protocols. However, they observed no significant decline after low-fatigue RT protocols. Thus, high-fatigue RT protocols might negatively impact performance, while low-fatigue RT protocols might not significantly affect it.
In the bodybuilding and fitness realm, the relentless pursuit of muscle hypertrophy (i.e., gaining muscle) often comes with challenges like fatigue and the interference effect. Understanding these components’ interaction is crucial for those aiming to build muscle.
Understanding the Interference Effect in Bodybuilding
Every bodybuilder feels the “burn” during exercise. It’s that moment when your muscles beg for a break, and each repetition seems insurmountable. But what’s behind this fatigue? While a certain amount of fatigue is necessary for muscle growth, it’s essential to avoid excessive fatigue during exercise.
Definition of Fatigue: Fatigue isn’t just about feeling tired. It’s a decline in the muscle’s force-producing capability, closely tied to the number of repetitions in a set (IZQUIERDO-GABARREN et al., 2010). Although it can be both mental and physical, we’ll focus on the physical aspect here.
Causes of Muscle Fatigue: Several factors cause muscle fatigue. Lactic acid build-up, energy depletion, and neural factors are significant contributors. Protocols that push muscles to failure create more mechanical and metabolic stress, like increased velocity loss (i.e., repetition speed slows down due to fatigue) and blood ammonia, compared to nonfailure training (Pareja-Blanco et al., 2020a; Pareja-Blanco et al., 2017). Moreover, as you exercise, your muscles’ energy reserves deplete, leading to fatigue.
Symptoms and Signs: Recognizing fatigue is crucial. Watch out for symptoms like decreased strength, reduced speed, and prolonged muscle soreness. Excessive training volume and insufficient recovery can disrupt performance and training adaptations due to interference between neuromuscular and metabolic processes (Murlasits et al., 2018; Pareja-Blanco et al., 2020b).
The Interference Effect
Definition and Overview: The interference effect is a hurdle many athletes encounter. It refers to a situation where combining resistance training (RT) and endurance training (ET) can decrease the effectiveness of one or both training types. Some studies suggest that the interference effect can reduce muscle growth. When adding endurance training to a resistance program, there’s a risk of the interference effect, which might slow down strength, power, and hypertrophy gains. Therefore, balancing strength and endurance training is vital to minimize the interference effect’s impact.
For example, one study reported that lifting weights before cardio led to better lower-body strength adaptations than doing aerobic exercise before weight training. However, the sequence didn’t affect aerobic capacity (Murlasits Z,2018). Most recent research indicates that the interference effect mainly affects those doing excessive volume.
Strategies to Minimize Interference: To minimize interference, avoid excessive volume, and ensure ample recovery time between sessions. But, you should perform sets with a moderate effort to prevent performance drops. By including these moderate-effort exercises, lifters can boost overall strength and conditioning without harming their endurance workout performance (Misner et al., 1990; Senefeld et al., 2013).
New Study on How Fatigue Can Deteriorate Performance.
A recent study published in the International Journal of Sports Physiology and Performance titled “Interference Effects of Different Resistance-Training Protocols on Rowing Ergometer Performance: A Study on Semiprofessional Rowers.” evaluates the interference effects of various fatiguing RT protocols on performance.
Fourteen semiprofessional male rowers underwent five different protocols:
- Control – no RT session was performed.
- Upper-body high-fatigue – 4 sets to failure during the bench pull exercise.
- Upper-body low-fatigue – 4 sets of 6 repetitions during the bench pull exercise.
- Lower-body high-fatigue – 4 sets to failure during the leg-press exercise.
- Lower-body low-fatigue – 4 sets of 6 repetitions during the leg-press exercise.
The study found that high-fatigue RT protocols that led to failure had a detrimental effect on subsequent rowing ergometer performance. On the other hand, low-fatigue RT protocols showed no significant impact on rowing performance. Contrary to the researchers’ hypothesis, the study found that the impact on rowing performance was similar for both upper-body and lower-body RT protocols. This suggests that fatigue in either muscle group can negatively affect rowing performance, including power output (Janicijevic et al., 2023).
Based on the study, athletes should steer clear of RT protocols leading to failure, as they can harm subsequent performance. Instead, they should opt for RT protocols that don’t induce excessive fatigue. Athletes can confidently include leg press and bench pull exercises in their training routine before rowing. However, to prevent performance drops, they should maintain moderate effort levels. By doing so, athletes can enhance strength and conditioning without affecting performance.
Athletes can confidently integrate leg press and bench pull exercises into their training routine before rowing practice. However, to avoid compromising performance, sets should be performed with moderate levels of effort. By incorporating these exercises with moderate effort, athletes can effectively enhance overall strength and conditioning without negatively impacting their performance.
In conclusion, building muscle is both a science and an art. Grasping the nuances of fatigue, muscle hypertrophy, and the interference effect can guide you toward optimal muscle growth and fatigue management. If you’re serious about muscle building, pushing to complete muscular failure and inducing excessive fatigue might not be the best approach.
IZQUIERDO-GABARREN, M., GONZÁLEZ DE TXABARRI EXPÓSITO, R., GARCÍA-PALLARÉS, J., SÁNCHEZ-MEDINA, L., DE VILLARREAL, E. S. S., & IZQUIERDO, M. (2010). Concurrent Endurance and Strength Training Not to Failure Optimizes Performance Gains. Medicine & Science in Sports & Exercise, 42(6), 1191-1199. https://doi.org/10.1249/MSS.0b013e3181c67eec
Janicijevic, D., Quidel-Catrilelbún, M. E. L., Baena-Raya, A., & García-Ramos, A. (2023). Interference Effects of Different Resistance-Training Protocols on Rowing Ergometer Performance: A Study on Semiprofessional Rowers. International Journal of Sports Physiology and Performance, 1-7. https://doi.org/10.1123/ijspp.2023-0210
Misner, J. E., Massey, B. H., Going, S. B., Bemben, M. G., & Ball, T. E. (1990). Sex Differences in Static Strength and Fatigability in Three Different Muscle Groups. Research Quarterly for Exercise and Sport, 61(3), 238-242. https://doi.org/10.1080/02701367.1990.10608685
Murlasits, Z., Kneffel, Z., & Thalib, L. (2018). The physiological effects of concurrent strength and endurance training sequence: A systematic review and meta-analysis. Journal of Sports Sciences, 36(11), 1212-1219. https://doi.org/10.1080/02640414.2017.1364405
Pareja-Blanco, F., Rodríguez-Rosell, D., Aagaard, P., Sánchez-Medina, L., Ribas-Serna, J., Mora-Custodio, R., Otero-Esquina, C., Yáñez-García, J. M., & González-Badillo, J. J. (2020a). Time Course of Recovery From Resistance Exercise With Different Set Configurations. The Journal of Strength & Conditioning Research, 34(10). https://journals.lww.com/nsca-jscr/fulltext/2020/10000/time_course_of_recovery_from_resistance_exercise.20.aspx
Pareja-Blanco, F., Rodríguez-Rosell, D., Aagaard, P., Sánchez-Medina, L., Ribas-Serna, J., Mora-Custodio, R., Otero-Esquina, C., Yáñez-García, J. M., & González-Badillo, J. J. (2020b). Time Course of Recovery From Resistance Exercise With Different Set Configurations. The Journal of Strength & Conditioning Research, 34(10), 2867-2876. https://doi.org/10.1519/jsc.0000000000002756
Pareja-Blanco, F., Rodríguez-Rosell, D., Sánchez-Medina, L., Sanchis-Moysi, J., Dorado, C., Mora-Custodio, R., Yáñez-García, J. M., Morales-Alamo, D., Pérez-Suárez, I., Calbet, J. A. L., & González-Badillo, J. J. (2017). Effects of velocity loss during resistance training on athletic performance, strength gains and muscle adaptations. Scandinavian Journal of Medicine & Science in Sports, 27(7), 724-735. https://doi.org/https://doi.org/10.1111/sms.12678
Senefeld, J., Yoon, T., Bement, M. H., & Hunter, S. K. (2013). Fatigue and recovery from dynamic contractions in men and women differ for arm and leg muscles. Muscle & Nerve, 48(3), 436-439. https://doi.org/https://doi.org/10.1002/mus.23836
The interference effect of exercise refers to the negative effects of combining weight training and endurance exercise in a single session. Concurrent training studies show that while anaerobic training boosts muscle strength and muscle mass, adding cardio, like cycling, can hinder protein synthesis pathways, notably mTOR. Conversely, endurance exercise activates AMPK, affecting skeletal muscle and reducing gains from strength training sessions. Training variables such as duration, modality, and training status play roles. For instance, a steady-state cardio might burn more calories but can impact molecular responses more than a maximal sprint.