What the World's Leading Resistance Training Researcher Says About Building Muscle
Key insights: 60-second read
- You only need two 30-minute sessions of resistance training per week - the minimum effective dose is just 4-6 hard sets per muscle group weekly, which can be done in one hour total.
- Muscle loss begins in your 30s - without resistance training, you lose approximately 0.5% of muscle mass per year, accelerating to 1-2% after age 50.
- It is never too late to start - 90-year-olds in nursing homes increased strength by 150% and 3 out of 10 could walk without their canes after just 8 weeks.
- Skip the cold plunge after training - cold water immersion within 20 minutes post-workout blunts muscle growth by reducing blood flow to the trained muscles.
We all know that resistance training is incredibly important for our health, especially as we age. But what if some of what we are doing in the gym is not actually getting us the results we both want and need?
Brad Schoenfeld, PhD, a recent guest on the Living Room podcast, is widely regarded as the world's leading strength training researcher. Brad has spent decades separating what the science really shows from what the fitness industry often tells us. He is a Professor of Exercise Science at Lehman College in New York, has published over 250 peer-reviewed papers, and his research has fundamentally changed how we understand muscle growth and resistance training.
In this conversation, he discusses the minimum effective dose of training, exercise selection, what GLP-1 drugs can do to your muscle mass, which supplements actually work, and most importantly, what you should be doing today to protect against the signatures of aging. So, let's take a look at what he said.
On this page
1. Who is Brad Schoenfeld, PhD?
About the Expert
Brad Schoenfeld, PhD, is a Professor of Exercise Science at Lehman College in New York and is widely regarded as one of the world's leading researchers on muscle hypertrophy and resistance training.
He has published over 250 peer-reviewed papers, and his work has fundamentally changed how we understand muscle growth. His research on training volume, rest periods, and the mechanisms of hypertrophy has influenced guidelines from the American College of Sports Medicine and other major organisations.
Schoenfeld started his career as a personal trainer and competitive bodybuilder, and his transition to academia was driven by a simple question: "Why don't we have more research on hypertrophy?" His work has since become the gold standard in the field.
2. Why Muscle Matters for Longevity
Without resistance training, you may begin to lose fundamental muscle mass at the rate of about 0.5% per year, starting sometime in your 30s. This loss accelerates to 1-2% per year after age 50.
The loss of type II muscle fibers - our fast-twitch, force-producing fibers - is particularly concerning. You can lose up to 25% of these fibers by the time you reach your 60s and 70s. These are the fibers that allow you to produce power quickly, which is essential for things like catching yourself during a fall.
The Hip Fracture Problem
Approximately 50% of older adults who experience a hip fracture never regain their physical independence. Within two years, the average individual who suffers a hip fracture is dead. This is frightening, and it underscores why maintaining muscle strength and power is so critical.
Resistance training improves balance and, even if you lose your balance, having greater power allows you to quickly reverse a fall before it becomes catastrophic.
But it is never too late to start. One of the most interesting studies he cited involved 90-year-olds in nursing homes. They had them do just leg extensions three days a week for 8 weeks. The results were profound:
- 150% strength gains in their knee extensors
- 50% improvement in functional capacity
- 3 out of 10 subjects were able to walk without the assistance of their canes
If 90-year-olds in nursing homes can see these results in just 8 weeks, there is hope for all of us - regardless of our starting point.
3. The Minimum Effective Dose
One of the most common questions Schoenfeld receives is: "How do I get the highest possible yield on my time?" The answer is surprisingly simple.
| Training Level | Sets per Muscle per Week | Time Required | Results |
|---|---|---|---|
| Minimum Effective Dose | 4-6 sets | 2 x 30 min sessions (1 hour total per week) | Very large benefits |
| Optimal for Most | 8-10 sets | 3-4 x 45-60 min sessions (2.25-4 hours total per week) | Maximise gains for non-athletes |
| Bodybuilder/Athlete | 15+ sets | 5+ hours per week | Maximising genetic potential |
Key principle: The sets need to be challengin. You need to be struggling on the last few repetitions. If you are't challenging yourself, your body won't realise it needs to get better, and the results won't likely follow. However, Schoenfeld clarifies that you do not need to train to all-out failure - being 1-2 reps short of failure still yields comparable results.
Reps in reserve (RIR) is a helpful concept. If you have an RIR of 1, you could have done one more rep. The problem is that unless you have trained to failure, you may not have a good gauge of what your RIR actually is. Schoenfeld recommends training to failure early on to understand what it feels like, then using RIR as a guide.
For beginners, Schoenfeld generally recommends 10-15 repetitions. Higher repetitions reinforce neural patterns and help you learn movement patterns, reducing the risk of injury compared to very heavy loads.
4. Rest Periods and Supersets
Schoenfeld's research on rest periods shows that when doing straight sets (e.g., bench press, rest, bench press), resting less than 90 seconds compromises muscle growth compared to resting 2+ minutes. However, this is primarily because shorter rest periods reduce the amount of load or number of reps you can perform on subsequent sets.
If you make up for this with an extra set, you can achieve similar results. One study found that resting 1 minute with more sets produced similar hypertrophy to resting 3 minutes, but in less total time.
Supersets are a great way to save time. A study from Schoenfeld's lab compared agonist-antagonist supersets (e.g., biceps and triceps, quads and hamstrings) to straight sets. The superset group finished their workouts in almost 40% less time with very similar hypertrophy results.
5. Protein Intake and Nutrient Timing
Schoenfeld has done a 180-degree turn on nutrient timing. He used to be the "guy with the shaker bottle," slamming a protein shake immediately after his last set to hit the anabolic window. The evidence now shows that for the vast majority of people, timing does not matter much.
What matters is total daily protein intake. The target is approximately 1.6 grams of protein per kilogram of body weight per day (for people who are relatively lean). This should be spread relatively evenly over 3-4 meals.
Schoenfeld notes that the idea you can only absorb 25 grams of protein at once is "silly." Recent research has looked at 100 grams of protein being used over 24 hours, suggesting the body can utilise much more than previously thought.
For people in a calorie deficit (including those using GLP-1 agonists), protein intake may need to be higher - 2 grams per kilogram or more - to preserve muscle mass. One of Schoenfeld's studies used 2.4 grams per kilogram and found it preserved muscle mass better than 1.6 grams.
6. Cold Plunge, Supplements, and Peptides
Cold Water Immersion
A meta-analysis by Schoenfeld's group found that if you do a cold plunge or apply cold water within 20 minutes after resistance training, you compromise muscle growth. The theory is that cold water immersion blunts blood flow to tissues, and muscle protein synthesis is initiated through nutrient delivery via the blood.
That said, doing it occasionally for soreness is unlikely to have a meaningful impact. But if you do it repeatedly after every workout, you may be limiting your gains.
Heat Application
A recent meta-analysis on heat application post-exercise showed a small positive effect on muscle growth. Heat enhances blood flow to tissues, which may support recovery. However, the effect is modest and should not be overstated.
Supplements That Work
From a muscle-building standpoint, creatine is the only supplement with true efficacy. About 70% of people respond to it, and those who are vegan or vegetarian tend to see better results because they get less from their diet. However, Schoenfeld notes that creatine does not produce steroid-like effects - it provides modest gains.
For health, he personally takes fish oil and vitamin D. He also consumes caffeine, which has good evidence for improving performance.
Protein supplements work only if you are not getting enough protein from your diet. Schoenfeld is a "food first" person and believes supplements should supplement your diet, not replace it.
Peptides and Exercise Mimetics
Schoenfeld is skeptical of peptides and exercise mimetics. He notes that there is very little controlled research on these compounds, and even less safety data. He personally would not go near peptides at this point because we cannot speak to what they might do in 5-10 years.
He believes it is unlikely that any drug will ever fully replace exercise because exercise involves multiple systems - including blood flow, hormonal responses, and neural adaptations - that are difficult to target with a single compound.
Brad Schoenfeld's message is clear, refreshing, and empowering: you do not need to spend hours in the gym to get meaningful results. Two 30-minute sessions per week, with hard but not necessarily maximal effort, can provide profound benefits for your health, function, and longevity.
If you are not currently resistance training, the evidence is overwhelming that you should start. If you are already training, consider whether you are making it more complicated than it needs to be. Consistency and progressive overload are far more important than finding the perfect routine.
As Schoenfeld put it, "Just getting into the gym is going to do the majority of what people need without paying attention to any of this noise."
- Grant
Frequently Asked Questions
What is the minimum amount of resistance training I need to do?
Two 30-minute sessions per week, performing one set of an exercise for each major muscle group, is the minimum effective dose. That is just one hour total per week. The sets need to be challenging - you should be struggling on the last few repetitions.
Is it too late to start resistance training if I am older?
Absolutely not. Research shows that even 90-year-olds in nursing homes can increase their strength by 150% and improve their functional capacity by 50% in just 8 weeks. It is never too late to start.
Should I do a cold plunge after my workout?
If your goal is muscle growth, research suggests you should avoid cold water immersion within 20 minutes after training as it blunts muscle growth by reducing blood flow to the trained muscles. If you want to do it for soreness occasionally, it is unlikely to have a meaningful impact.
How much protein should I eat each day?
Around 1.6 grams per kilogram of body weight is a good target for most people. If you are in a calorie deficit (including if you are using GLP-1 drugs), you may need 2 grams per kilogram or more to preserve muscle mass.
Do I need to train to failure to build muscle?
No. Being 1-2 reps short of failure yields comparable muscle growth to training to failure. This is good news for those who find training to all-out failure uncomfortable or demotivating.
One key insight from this interview
"Just two 30-minute resistance training sessions per week - with hard but not necessarily maximal effort - can provide profound benefits for your health, function, and longevity. Consistency trumps complexity every time."
Need Help with Your Exercise Program?
If you are unsure where to start with resistance training or have pain that is holding you back, we can help. Learn more about our physiotherapy services in Port Macquarie.
Want personalised guidance?
If you would like help making sense of your exercise routine, pain, or rehabilitation, you can book with Grant either in Port Macquarie or via an online telehealth consultation.
