Everything You Need To Know About Intensity & Volume
Exploring Training Volume and Intensity for Effective Muscle Development
Nerd Alert: High-Concept Fitness Analysis Ahead!
Warning: This article delves deep into the intricacies of training volume, intensity, and their interplay in muscle development. It's packed with scientific insights, detailed analyses, and perhaps more graphs than a high school math class. Perfect for fitness enthusiasts who love to geek out on the nitty-gritty details and don't mind a brain workout along with their physical one. If you're ready to dive into the depths of strength training theory, you're in the right place. Just don't say I didn't warn you about the impending intellectual gains!
Introduction - Intensity & Volume
In resistance training, the debate between high intensity and high volume training has long been a subject of discussion among athletes, bodybuilders, and fitness enthusiasts. While some advocate for low-volume, high-intensity approaches, as popularized by figures like Mike Mentzer, others lean towards high-volume methods, such as German Volume Training. This article aims to dissect and demystify the intricate relationship between training intensity and volume, two fundamental concepts in strength and hypertrophy training.
Understanding the balance between intensity (how hard you train) and volume (how much you train) is crucial for effective program design. However, common perceptions about their inverse relationship often lead to confusion and inefficiencies in training. By presenting a unified model of intensity and volume interaction, this article seeks to clarify how these factors influence muscle adaptation and growth, and how they can be optimally applied in a training regimen.
We will delve into the nuances of training thresholds such as Minimum Effective Volume (MEV), Maximum Adaptive Volume (MAV), and a novel concept called Maximum Intensity Volume (MIV). These thresholds serve as critical markers to guide training intensity and volume for optimal muscle growth and recovery. Additionally, we will explore the concept of diminishing returns in training volume, a critical consideration for understanding the efficiency and sustainability of different training volumes.
Through this exploration, supported by key studies and research findings, we aim to provide valuable insights for both novice and experienced trainers. This will enable a more informed approach to strength training, ensuring that each session contributes effectively towards the desired muscle adaptations and overall fitness goals.
Rethinking the Inverse Relationship Between Intensity and Volume in Strength Training
Understanding the Basic Concept: It's a widely accepted principle in strength training that volume and intensity have an inverse relationship. Simply put, as one increases, the other tends to decrease. This concept is rooted in several key factors:
Energy and Recovery Constraints: Intense training sessions, particularly those pushing muscles close to failure, are extremely demanding on the body. They not only consume significant energy but also cause considerable muscle damage. The body's capacity for repair and recovery is finite. Overly frequent high-intensity training heightens the risk of overreaching, potentially leading to fatigue, injury, and a decline in performance.
Stress Response and Adaptation: The body's adaptive response to stress is a cornerstone of physical training. High-intensity workouts deliver a potent stimulus for muscle growth and strength improvements. However, due to their strenuous nature, they necessitate extended recovery periods. Conversely, training at a lower intensity allows for increased frequency (higher volume) but may offer a weaker stimulus in each session.
Injury Risk Management: High-intensity training, especially when performed close to failure, can heighten injury risk due to potential form breakdown and fatigue. Managing the balance between intensity and volume is crucial in reducing this risk. Opting for either a lower volume of high-intensity training or a higher volume of lower-intensity training can be effective strategies, each minimizing the chance of injury.
Challenging the Traditional View: However, applying the concept of an inverse relationship too rigidly can lead to misconceptions. For instance, if we were to graph a direct inverse relationship, it would imply that training beyond one set at 0 RIR (Reps in Reserve) with the same relative intensity is not feasible, and increasing intensity always necessitates a decrease in volume. This overly simplistic view doesn't align with practical training experiences or the capabilities of individuals with varying genetic predispositions.
In reality, individuals, including those not genetically gifted for muscle growth (colloquially referred to as having "Woody Allen genetics"), can perform more than one set at 0 RIR per muscle group each week. Moreover, increasing intensity does not automatically lead to a reduction in the number of sets. Therefore, it's important to adopt a more nuanced understanding of the relationship between volume and intensity in strength training.
The revised curve in our analysis addresses the issues previously encountered with the directly inverse relationship model between intensity and volume:
Sustaining Intensity Beyond One Set at 0 RIR: Contrary to the idea that training beyond a single set at 0 RIR (Reps in Reserve) with the same relative intensity is not viable, the new curve demonstrates that intensity can indeed be maintained at 0 RIR for more than one set. This intensity then gradually decreases as we approach the highest total volume possible for muscle growth. This modification aligns more closely with both empirical evidence and everyday training experiences. It challenges the viewpoint held by staunch advocates of ultra-low volume training methods, such as those favored by Mentzer's followers.
Rethinking the Direct Inverse Relationship: Traditionally, if intensity and volume were directly inversely related, an increase in one would automatically lead to a decrease in the other. However, the new curve introduces a critical adjustment: its flat portion suggests that an increase in intensity doesn't always correlate with a decrease in volume. This adjustment is more representative of real-world training scenarios, where it's possible to perform multiple sets at maximum effort.
In essence, the updated curve offers a more realistic and practical depiction of the training landscape, acknowledging that the relationship between intensity and volume is not as rigid as once thought. It reflects the understanding that multiple sets can be performed at or near failure, providing a more nuanced perspective on how we can approach training for muscle growth.
Training Thresholds on the Non-Linear Intensity-Volume Curve
Let’s highlight three critical points: the Minimum Effective Volume (MEV), where the least amount of work generates noticeable gains; the Maximum Adaptive Volume (MAV), which represents the optimal workload for maximal gains; and a novel concept called "Maximum Intense Volume" (MIV), indicating the highest volume at which we can perform at 0 RIR.
MEV - Minimum Effective Volume
It is suggested that anywhere from 1-4 sets at 0 RIR, can stimulate up to 64% of potential gains, making this lower threshold for gains a valid choice for people who are short on time or want to spend less time in the gym and more time recovering. Mike Mentzer and his devotes, advocate 1 set to failure per muscle group per week, to give you an idea of how MEV is utilized in the bodybuilding community.
MAV - Maximum Adaptive Volume
At the furthest end of the volume spectrum, we find the theoretical limit for how many sets a person can perform before getting negative returns. It’s notable that this upper threshold has yet to be discovered by any studies conducted, despite there being a number of very high volume studies.
Recently, a study was conducted on the upper the effects of high volume training on strength and hypertrophy. The study involved thirty-one resistance-trained males, ages 21-27, with 3-7 years training experience. All starting at 22 sets per week (already a high volume), over the course of 12 weeks, one group added 6 sets every 2 weeks to their quad training, another group 4 sets, and the control group remained the same. By the end of the 12 weeks, the 6 set group finished with 52 total sets, all taken to within 2 RIR, with one set per exercise taken to concentric failure. The 4 set group ended at 37, and the final control group remained at 22 sets.
The biggest takeaway here came from the trainee’s ability to train close to and to failure for up to 52 sets per muscle group per week — an extremely high total weekly volume (MAV), implying the upper limit to volume is yet to be scientifically discovered.
MIV - Maximal Intensity Volume
The third point on the graph is a novel concept representing the total number of sets a person can perform at 0 RIR. This point may be closer or at MEV for some or closer to MAV for others. This depends on a number of factors like age, training experience, recovery profile, previous training volume, and more.
Previous training volume in particular probably plays a big role in ones ability to train close to or to failure at higher volumes. In the example of the 52 set study, the trainees were taking sets to failure way beyond their MEV and likely right up to their MAV. One possible takeaway is that as you accumulate volume over time, your MIV slides towards the MAV.
Diminishing Returns and Training Volume
So far, our graph depicting the relationship between intensity and volume has been based on a standard scale, with equal spacing between each vertical and horizontal line. This uniform approach is suitable for analyzing theoretical concepts like MEV, MAV, and MIV, as well as for understanding the overall shape of the relationship between intensity and volume. However, to accurately measure total gains, which are represented by the area under the curve, we need to modify the graph's scale and layout. This will help us more precisely depict the real-world impact of these variables on muscle gains. We need to consider two facts about volume and intensity.
Additional volume has diminishing returns on total gains.
In the 52 set study (Schoenfeld, Ogborn, & Krieger, 2016), the difference in CSA and muscle thickness was only slightly (and likely statistically insignificant) in favor of the higher set groups. What this hints at is that as you train at higher and higher volumes, any additional volume will have less and less of an effect on total gains.
As you train closer to 0 RIR, gains go up significantly.
In light of recent research, it's becoming increasingly clear that training intensity, particularly how close one trains to failure, plays a pivotal role in muscle development. The comprehensive study by Robinson et al. (2023) delves into this phenomenon, revealing a significant correlation between lower repetitions in reserve (RIR) and enhanced muscle hypertrophy. As trainees approach a 0 RIR, effectively pushing their sets closer to failure, there is a noticeable uptick in muscle growth. This finding underscores the importance of training intensity in resistance training programs aimed at maximizing muscle hypertrophy.
Let’s use a real life example to help modify the graph, taking these facts into account. According to a batch of resent research on volume, 1-4 sets at 0 RIR can get us ~64% of maximum gains — a surprisingly large percentage. Shaded in red is the total gains we make training between 1-4 sets at 0 RIR. Notice anything about this area?
The red-shaded area currently depicted on our graph does not accurately correspond to 64% of the total area under the curve—it appears to represent closer to 20%. To create a graph that more accurately reflects the actual gains, the first 4 sets should occupy a substantially larger portion. The revised graph below incorporates adjustments to both the x and y axes. These changes ensure that the graph realistically represents the concept of diminishing returns with additional volume, and the increased gains achieved when training closer to failure.
Examining the impact of 5-8 total weekly sets on maximal muscle gains reveals an interesting dynamic. In this scenario, the area shaded in red on our graph corresponds to 84% of the maximum possible gains. This illustrates that although the number of sets has doubled compared to the initial 1-4 sets, the incremental gain is only an additional 20%. This highlights the diminishing return effect in muscle development, where increasing the number of sets significantly does not proportionally increase gains.
By adjusting our graphical representation, we clearly see how initial training sets contribute a substantial portion of potential gains, while additional sets offer progressively smaller improvements. This insight is crucial for optimizing training regimens, emphasizing the importance of balancing volume and intensity to maximize muscle development efficiently.
Applications For Your Training
Earlier, we delved into a study by Enes and colleagues (Enes, De Souza, & Souza-Junior, 2023) titled "Effects of Different Weekly Set Progressions on Muscular Adaptations in Trained Males: Is there a Dose-Response Effect?" in which trends observed in the study hinted at a potential marginal advantage for muscle growth at higher volumes, suggesting that increasing the number of sets might lead to slightly better hypertrophy results. This finding aligns with the concept of a dose-response relationship in resistance training, where a higher 'dose' of exercise (in terms of sets and repetitions) could yield greater muscular adaptations. But how should this inform our training?
Following the discussion of MEV (Minimum Effective Volume), MAV (Maximum Adaptive Volume), and MIV (Maximum Intensity Volume), it's crucial to delve deeper into its practical implications:
MEV - Minimum Effective Volume