Key Points of the Article:
- The study suggests that exercise variation does not necessarily lead to greater muscle growth or strength gains compared to consistent training.
- Both groups in the study—those using varied exercises and those sticking to the same exercises—achieved similar muscle size and strength improvements.
- Lifters can choose either approach based on personal preference or convenience without worrying about compromising results.
Should You Change Your Workouts Every Week? Insights on Exercise Variation
Muscle hypertrophy, defined as the increase in muscle size, is influenced by progressive overload.1 However, various factors influencing muscle growth include the type, intensity, and exercise frequency.2,3 A central question in this domain is whether consistently changing workout routines is necessary to achieve optimal muscle growth.
Studies have demonstrated that incorporating different exercises targeting the same muscle group can enhance muscle hypertrophy by recruiting a broader range of muscle fibers and stimulating various physiological adaptations. For example, a 2021 study found that exercise selection significantly influenced regional muscle hypertrophy, suggesting that different exercises can elicit distinct hypertrophic responses in various muscle regions.4 On the other hand, a 2019 eight-week study comparing fixed and varied exercise programs in resistance-trained men. Both groups showed significant muscle thickness and strength increases, with no difference in hypertrophy outcomes. However, participants in the varied group reported higher motivation levels, highlighting the psychological benefits of variation.5 A new study by Kassiano et al., published in Research Quarterly for Exercise and Sport (2024), offers clarity: varying your exercises may not be as critical as previously thought.6
Overview of the Study on Exercise Variation
The researchers aimed to settle the debate between varied and consistent training by examining their effects on muscle hypertrophy (growth) and strength. The study involved 70 untrained young women divided into two groups:
- Constant Resistance Exercises (CON-RE): This group performed the same exercises—45° leg press and stiff-leg deadlift—throughout the program.
- Varied Resistance Exercises (VAR-RE): This group switched exercises each session, adding movements like hack squats and prone leg curls.
Both groups trained three times per week for 10 weeks, completing two sets of 10–15 repetitions per exercise. Diets were monitored to ensure consistency, and muscle size was measured using advanced ultrasound technology.
Results: Does Exercise Variation Result in More Muscle Growth?
Muscle Growth: Both groups experienced significant increases in muscle size across the anterior, lateral, and posterior thigh regions. However, there were no differences in muscle growth between the groups.
When averaged across all regions of the thigh, the overall hypertrophy results were:
CON-RE Group: 9–11% average increase in muscle thickness
VAR-RE Group: 10–11.5% average increase in muscle thickness
The differences were minimal, suggesting that varying exercises did not enhance overall muscle growth compared to sticking with the same exercises. The slightly higher average in the VAR-RE group was not statistically significant, meaning it could be attributed to natural variation rather than the intervention itself.
Strength Gains: Strength improvements were also similar. The 45° leg press increased from 30% to 32%, while leg extension strength (an untrained exercise) improved by 24–29%. These results show that consistent workouts and varied routines were equally effective for increasing muscle strength.
Training Volume: Interestingly, the constant training group accumulated a slightly higher total training volume. However, this did not translate into superior results, suggesting that volume alone wasn’t the decisive factor.
Unexpected Findings: Both groups improved in exercises they hadn’t specifically trained for, a phenomenon known as the “transfer effect.” This means strength gains in one exercise can carry over to others, even if they weren’t part of the routine.
Making Sense of the Exercise Variation vs Constant Training
The study highlights that both approaches (not changing your exercises vs. exercise variation) stimulate the muscles sufficiently for growth and strength. For instance, the 45° leg press and hack squat, although different, target similar muscles, leading to comparable outcomes. This finding aligns with previous research showing no additional benefits from changing exercises frequently.7,8 9
Practical Applications
For bodybuilders, fitness enthusiasts, and weekend warriors, this study offers valuable takeaways:
Choose Based on Preference: Whether you prefer a varied routine or enjoy sticking to familiar exercises, both methods work. This flexibility allows you to design workouts around your preferences and equipment availability.
Consistency Matters More Than Variety: The key to progress lies in showing up and progressively overloading your muscles, whether you stick to the same exercises or mix things up.
Don’t Overcomplicate Your Training: For beginners, mastering the basics with consistent exercises may be more effective than constantly switching routines. Advanced lifters can introduce variation for mental engagement or to target specific weak points.
Monitor Total Volume: Regardless of your approach, ensure you lift enough weight and complete enough sets to stimulate muscle growth effectively.
Conclusion
The debate over exercise variation often divides the fitness community, but this study provides a clear answer: you don’t need to overhaul your workout routine weekly to see results. Both consistent and varied routines lead to significant gains in muscle size and strength. Whether you’re a seasoned bodybuilder or new to the gym, focus on what keeps you motivated and ensures long-term adherence. After all, the best workout is the one you’ll stick with.
References
1 Ihsan, F., Nasrulloh, A., Nugroho, S. & Yuniana, R. Effect Weight Training on Muscular Hypertrophy: A Systematic Review. Pedagogy of Physical Culture and Sports 27, 439-447 (2023). https://doi.org/10.15561/26649837.2023.0601
2 Costa, B. et al. Does Varying Resistance Exercises for the Same Muscle Group Promote Greater Strength Gains? The Journal of Strength and Conditioning Research 36, 3032-3039 (2022). https://doi.org/10.1519/jsc.0000000000004042
3 Steele, J. et al. Meta-analysis of variation in sport and exercise science: Examples of application within resistance training research. J Sports Sci 41, 1617-1634 (2023). https://doi.org/10.1080/02640414.2023.2286748
4 Zabaleta-Korta, A., Fernández-Peña, E., Torres-Unda, J., Garbisu-Hualde, A. & Santos-Concejero, J. The Role of Exercise Selection in Regional Muscle Hypertrophy: A Randomized Controlled Trial. Journal of Sports Sciences 39, 2298-2304 (2021). https://doi.org/10.1080/02640414.2021.1929736
5 Baz-Valle, E., Schoenfeld, B. J., Torres-Unda, J., Santos-Concejero, J. & Balsalobre-Fernández, C. The effects of exercise variation in muscle thickness, maximal strength and motivation in resistance trained men. PLoS ONE 14 (2019).
6 Kassiano, W. et al. Muscle Hypertrophy and Strength Adaptations to Systematically Varying Resistance Exercises. Research Quarterly for Exercise and Sport (2024). https://doi.org/10.1080/02701367.2024.2409961
7 Maeo, S. et al. Greater Hamstrings Muscle Hypertrophy but Similar Damage Protection after Training at Long versus Short Muscle Lengths. Med Sci Sports Exerc 53, 825-837 (2021). https://doi.org/10.1249/mss.0000000000002523
8 Currier, B. S. et al. Resistance training prescription for muscle strength and hypertrophy in healthy adults: a systematic review and Bayesian network meta-analysis. Br J Sports Med 57, 1211-1220 (2023). https://doi.org/10.1136/bjsports-2023-106807
9 Schumacher, L. M. et al. Sustaining Regular Exercise During Weight Loss Maintenance: The Role of Consistent Exercise Timing. J Phys Act Health 18, 1253-1260 (2021). https://doi.org/10.1123/jpah.2021-0135
