Key takeaways
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Resistance Training Prescription for Muscle Strength and Hypertrophy in Healthy Adults: A Systematic Review and Bayesian Network Meta-Analysis
Aim
Determine how different combinations of strength training (RTx) prescription variables (load, sets, and frequency) affect muscle strength and hypertrophy. Data sources MEDLINE, Embase, Emcare, SPORTDiscus, CINAHL and Web of Science were searched up to February 2022.
Eligibility criteria
We included randomized trials that included healthy adults, compared at least 2 predefined conditions (no exercise control [CTRL] and 12 RTx, differentiated by load, sets, and/or weekly frequency), and reported muscle strength and/or hypertrophy.
Analysis
Systematic review and Bayesian network meta-analysis methodology was used to compare RTxs and CTRL. The values of the surface under the cumulative classification curve were used to classify the conditions. Confidence was assessed with threshold analysis.
Results
The strength network included 178 studies (n=5097; women=45%). The hypertrophy network included 119 studies (n=3364; women=47%). All RTx were superior to CTRL for muscle strength and hypertrophy. Higher load prescriptions (>80% of single repetition maximum) maximized strength gains, and all prescriptions promoted muscle hypertrophy similarly.
Although the calculated effects of many prescriptions were similar, three-times-a-week, higher-load, multi-set training (standardized mean difference [95% credible interval]; 1.60 (1.38 to 1.82 ) vs CTRL) was the highest ranked RTx for strength, and higher load training, multiset, twice a week (0.66 (0.47 to 0.85) vs CTRL) was the highest ranked RTx for hypertrophy. Threshold analysis showed that these results were extremely robust.
Probability for each condition ranked among the three most effective for strength (A) and hypertrophy (B). Scores closer to 100% indicate a higher probability of being ranked in the top three. Resistance training prescriptions are indicated with a three-character acronym, XY#, where X is load (H, ≥80% 1 repetition maximum (1RM); L, <80% 1RM); Y is sets (M, multiple set; S, single set); and # is the weekly frequency (3, ≥3 days/week; 2, 2 days/week; 1, 1 day/week), respectively. For example, ’HM2’ denotes twice-weekly, multiset, higher load training. CTRL, control group without exercise.
Conclusion
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What is already known
- Resistance training with a varying number of variables (load, sets, weekly frequency) powerfully increases strength and muscle mass.
- Strength training prescription involves multiple variables, but the optimal strength training prescription remains controversial.
- Network meta-analysis allows for simultaneous comparisons between multiple resistance training prescriptions.
What does this study contribute?
- This network meta-analysis is the largest synthesis of resistance training prescription data from randomized trials.
- All resistance training prescriptions are better than no exercise for strength and hypertrophy in healthy adults.
- The top-ranked strength prescriptions were characterized by higher loads and the top-ranked hypertrophy prescriptions were characterized by multiple sets.
- All resistance training prescriptions increased strength and hypertrophy, suggesting that healthy adults can adopt a resistance training prescription of their choice and preference.
How this study changes practice
Since all protocols increased strength and hypertrophy, rather than determining an “optimal” protocol , future work could determine minimum “doses” of resistance exercise and practices to promote engagement and adherence to this form of exercise. exercise that promotes health.
Comments
Lifting weights regularly builds strength and muscle, and it doesn’t matter if those weights are heavy or light. It’s the act itself, and being consistent, that pays off, according to a new study.
All forms of strength training are beneficial, including bodyweight exercises like planks, lunges and push-ups, according to kinesiologists at McMaster University in Ontario, Canada, who looked at weight, frequency and consistency.
"There are a dizzying number of factors and combinations to consider when creating a weightlifting program to maximize strength and muscle growth," said kinesiology professor Stuart Phillips, who conducted the study with graduate students Bradley Currier and Jonathan Mcleod. "This is an age-old debate among athletes and strength and conditioning coaches: which combination leads to the best gains?"
For the study, researchers reviewed 192 studies that included more than 5,000 people in total. The work capped years of focus on three strength training variables: how much you lift; how often; and how many times, including one, two, three or more training sessions per week. Researchers collected and analyzed massive amounts of data.
Many fitness experts say that lifting the heaviest weights three to five times is the best way to build strength and that using weights that a person can lift eight to ten times is best for building muscle size, they noted. the authors of the study.
McMaster researchers have spent the last decade rejecting the idea that heavier is better . His previous research found significant gains from lifting lighter weights 20 to 30 times, toward the point of exhaustion.
In this review, researchers found that lifting heavier weights was the best way to gain strength . However, to maximize muscle size , weight was less important than repetitions.
"Our analysis shows that each resistance training prescription resulted in gains in strength and muscle mass," Currier said in a university news release. "Complex prescriptions are sufficient but unnecessary for gaining strength and muscle. Simple programs are extremely effective and the most important result is that people can benefit from any weightlifting program." He urged people to seek guidance if they don’t know where to start and how to move forward. "It doesn’t have to be complicated," Currier emphasized.
Researchers called the findings good news for anyone interested in gaining strength and maintaining more muscle. This helps prevent injuries, maximizes mobility and optimizes metabolism.
"The most important variable to master is compliance ," Mcleod said. "Once you have that down, then you can worry about all the other subtle nuances, but our analysis clearly shows that many seemingly important variables simply aren’t that essential for the vast majority of people."
The findings were published online in the British Journal of Sports Medicine .
