Breaks Between Sets: The Overlooked Element of Effective Strength Training
When most people think about strength training, the first things that come to mind are the exercises themselves—whether it’s deadlifts, squats, bench presses, or other compound movements that build power. While these exercises are undeniably important, there's one often overlooked factor that can make or break your workout: your rest periods between sets. Believe it or not, the amount of time you rest during a workout is a key player in maximizing performance, optimizing muscle growth, and aiding recovery. But how do you know how long to rest between sets, and how can you use this time to your advantage? Let’s break it down in more detail!
The Importance of Active Rest
While taking breaks is crucial, it doesn't mean you should just sit there and do nothing. You can use your rest periods effectively to enhance your training even further. Active rest involves doing low-intensity movements between sets, such as walking, light cycling, or stretching. This can help maintain blood flow to the muscles, reduce stiffness, and keep your heart rate up for better cardiovascular conditioning.
For example, if you’re resting after a set of squats, consider doing some bodyweight lunges or light mobility exercises for your hips. This keeps the muscles engaged and can improve your overall workout quality.
Listening to Your Body
While general guidelines for rest periods are helpful, don’t forget that your body’s feedback is one of the most valuable tools you have. If you feel completely gassed after a set, take an extra 30 seconds to catch your breath. If you're ready to go after a shorter rest, trust your body and get back to it.
Why Breaks Matter During Strength Training
Strength training isn’t just about how hard you push yourself during each set—it’s also about how well you recover during your breaks. When you perform an intense lift, like a heavy squat or deadlift, your body taps into your ATP (adenosine triphosphate) energy stores. These stores get depleted quickly, leading to muscle fatigue. Proper rest between sets is crucial because it allows your body time to restore these energy reserves, ensuring you can perform at your best for each subsequent set.
The Cellular Differences: Endurance vs. Strength Training
When training for endurance, your body primarily relies on aerobic energy systems, which involve continuous, lower-intensity efforts where oxygen plays a key role in fueling your muscles. At the cellular level, endurance training stimulates the production of mitochondria (the powerhouses of your cells), increasing your ability to produce ATP over extended periods. However, this process is slower compared to the anaerobic systems used during strength training.
Endurance training also leads to the buildup of lactate (lactic acid) as a byproduct of anaerobic metabolism. However, in endurance athletes, the body becomes more efficient at clearing lactate, minimizing fatigue and allowing longer, sustained efforts.
In contrast, strength training involves high-intensity, anaerobic efforts where ATP is used rapidly but is not replenished as quickly because it relies more on glycolysis (the breakdown of glucose without oxygen). This leads to the buildup of lactic acid (lactate), which contributes to muscle fatigue and the “burn” felt during heavy lifts. Strength training also generates acetyl-CoA, a key molecule produced when glucose is broken down into pyruvate. Under anaerobic conditions, acetyl-CoA accumulates because it cannot be fully processed in the mitochondria and instead contributes to lactate production. This accumulation plays a role in the muscle fatigue that is commonly experienced during high-intensity strength exercises.
Additionally, acetyl groups are involved in acetylation, a process where acetyl groups are added to proteins within the muscle cells. This modification affects various enzymes and proteins related to muscle repair, growth, and energy regulation. The process of acetylation is particularly important in strength training as it influences the recovery of muscle fibers and the adaptation to the stress of lifting heavy weights.
What Happens Between Sets?
During rest intervals, the processes happening inside your body differ for endurance versus strength training:
For endurance athletes, rest allows the replenishment of glycogen stores and helps in removing lactate from muscles, preventing excessive fatigue. Adequate rest also supports the recovery of ATP levels and ensures that muscles maintain the ability to continue contracting for longer periods. This helps to clear the lactate buildup, allowing muscles to function at their best for continuous, low-intensity efforts.
For strength training, rest periods are crucial for restoring phosphocreatine (PCr), which is used to regenerate ATP. Phosphocreatine stores are the body’s quick source of energy for short, intense bursts of activity, like a heavy deadlift or squat. Without proper rest, these stores aren’t replenished, leading to a decrease in power output and an inability to lift as heavily during subsequent sets. Additionally, rest allows for the removal of acetyl-CoA and lactate from the muscle cells. Acetyl-CoA buildup contributes to the fatigue that you feel during high-intensity strength work, while lactate accumulation directly contributes to muscle soreness and the burn sensation. Adequate rest gives your body time to clear these byproducts, optimize energy production, and restore muscle function.
Studies support the importance of recovery for optimizing performance. Research published in the Journal of Strength and Conditioning Research found that short rest periods (30 seconds or less) are effective for increasing endurance but significantly reduce strength performance due to incomplete recovery of ATP and phosphocreatine. On the other hand, longer rest periods (2-5 minutes) allow for nearly full replenishment of phosphocreatine stores, enhancing strength output during successive sets.
In strength training, the accumulation of acetyl-CoA and lactate are key contributors to the muscle fatigue and soreness you feel after intense sets. Research in Frontiers in Physiology highlights that during rest, the body works to clear these byproducts, allowing for greater muscle function and strength in subsequent sets. Additionally, the process of muscle protein synthesis (MPS), which is crucial for muscle growth and repair, is optimized during rest. This process is influenced by acetylation, which regulates protein function and plays a role in adapting the muscle cells to the stress of heavy lifting.
The Importance of Rest for Recovery
Without adequate breaks, fatigue will set in faster, and muscle performance can decline more quickly. The goal of your rest period is to optimize recovery so you can maximize the effort of each set. If you’re training for strength, take longer breaks to replenish your ATP and phosphocreatine stores, clear acetyl-CoA and lactate buildup, and enhance your power output for each lift. If you’re training for endurance, shorter rests help improve your body’s ability to handle prolonged efforts by aiding in the removal of lactate and ensuring your muscles stay primed for continuous work.
How Long Should Your Breaks Be?
The ideal length of your break depends on the goal of your workout. Whether you’re training for strength, muscle growth, or endurance, your rest time will differ.
1. Strength Training (Heavy Lifting) – Longer Breaks (2–5 minutes)
When your focus is on building raw strength, such as through low-rep, high-weight lifts (think: 1–5 reps), you need longer breaks between sets. This allows your body enough time to replenish its ATP stores, which is essential for lifting maximal weights in subsequent sets.
Science: Studies show that longer rest periods allow for better performance during high-intensity lifts, as they ensure the body can restore energy stores needed for heavy lifting (Schick et al., 2010). This is critical if you’re training close to your one-rep max (1RM).
2. Hypertrophy (Muscle Growth) – Moderate Breaks (60–90 seconds)
For muscle growth, the goal is to create enough tension in the muscles for a prolonged period, which results in hypertrophy (muscle growth). Here, shorter breaks of 60–90 seconds between sets allow you to maintain intensity while keeping the muscles under constant tension.
Science: Research suggests that shorter rest periods during hypertrophy training lead to greater muscle fiber recruitment and better overall muscle growth due to the increased time under tension (Schoenfeld, 2010).
3. Endurance Training – Short Breaks (30–60 seconds)
If you’re training for muscular endurance, which involves lighter weights and higher reps (typically 12–20 reps per set), your rest periods should be shorter—around 30–60 seconds. Shorter breaks help keep the heart rate elevated, allowing for improved cardiovascular fitness while challenging your muscles to endure sustained activity.
Science: Shorter breaks maintain a high level of intensity throughout the workout and help improve muscular endurance (Zahiri et al., 2018). This type of training works well for sports or activities requiring stamina over strength.
Why Heavier Lifting Demands More Rest
When you’re lifting heavy, particularly at higher intensities (around 85-90% of your one-rep max), the demands on your muscles and energy systems increase dramatically. The body requires more time to recover from such intense efforts because of the depletion of ATP, phosphocreatine stores, and the buildup of metabolic byproducts like lactate and acetyl-CoA. These factors not only contribute to immediate muscle fatigue but also play a role in the muscle damage that occurs with heavy lifting.
Muscle fibers—especially type II fibers, which are recruited during high-intensity lifts—undergo microscopic tears during each set. This muscle damage is a key stimulus for muscle growth and strength gains. However, repairing these fibers requires adequate recovery and protein synthesis, which can be compromised if rest is insufficient. Without proper rest between sets, you increase the likelihood of muscle strain or overtraining, and you may see a decrease in performance over time due to inadequate recovery of damaged tissue.
Additionally, phosphocreatine (PCr) stores, which are essential for replenishing ATP, take longer to recover when lifting heavy. PCr is quickly used up during explosive, high-intensity lifts but is replenished relatively slowly compared to other energy systems. Insufficient rest between sets means that PCr stores aren't fully restored, leading to a rapid decline in strength output during subsequent sets. This is why strength athletes often rest 2-5 minutes between sets to allow for near-complete recovery of phosphocreatine stores.
Periodizing Your Training: How to Adjust Breaks
Periodization is the practice of cycling through different phases of training intensity. When you're focusing on strength, you’ll want longer breaks, but during a conditioning phase or when focusing on hypertrophy, you can incorporate shorter breaks. Here's a basic framework for adjusting breaks over time:
Phase 1: Strength (4–6 weeks) – Longer rest periods of 3–5 minutes between sets.
Phase 2: Hypertrophy (4–6 weeks) – Moderate rest periods of 60–90 seconds to maximize muscle tension.
Phase 3: Endurance (4–6 weeks) – Shorter rest periods of 30–60 seconds to promote endurance.
This cycle can help you build well-rounded strength and fitness over time, while ensuring that your body isn’t plateauing by constantly training the same way.
What Happens in Your Body During Breaks?
When you take a break between sets, a few things are happening in your body:
Energy Restoration: During rest, your body works to replenish ATP stores. This is important for maintaining strength and power for subsequent sets, especially when you’re lifting heavy. It also helps clear lactic acid and other metabolic byproducts that accumulate during intense lifting, reducing muscle fatigue.
Muscle Repair: While breaks give your muscles time to recover, they’re also setting the stage for the repair process. When you work out, you create tiny tears in muscle fibers, and during the rest period, your body works to repair those fibers, making them stronger and larger. This is the foundation for muscle growth (hypertrophy).
Hormonal Responses: Taking breaks helps regulate the levels of hormones like testosterone and growth hormone, which are critical for muscle repair and growth. Proper rest helps ensure your body releases the right hormones at the right times for optimal muscle-building conditions.
How to Use Breaks to Your Advantage
Stay Focused: Instead of using your rest periods to scroll through your phone, use them to mentally prepare for your next set. Visualize your next lift or set of reps to maintain focus.
Stay Hydrated: This is a great time to drink water and replenish electrolytes, especially if you're doing a high-volume or long workout.
Active Rest: You can also do light movements like walking, stretching, or foam rolling during rest periods to keep your body engaged without expending too much energy.
Rest between sets isn’t just about taking a breather—it’s about allowing your body to recover, adapt, and prepare for the next round of lifting. Whether you're lifting heavy for strength, targeting muscle growth, or focusing on endurance, the way you periodize your training and manage your rest periods can have a huge impact on your results. Remember, it’s not all about pushing through without stopping. Strategic rest is the secret to getting stronger, building muscle, and improving endurance.
Hope that helps,
Happy Exercising!
Robyn
References:
Schick, E. E., et al. (2010). The influence of rest interval length on the performance of well-trained resistance-trained women. Journal of Strength and Conditioning Research, 24(4), 1173–1181.
Schoenfeld, B. J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research, 24(10), 2857–2872.
Zahiri, R., et al. (2018). Effects of different rest interval lengths on muscular endurance performance and cardiovascular responses. European Journal of Sport Science, 18(7), 1–9.