Are you trying to build strength or is your main goal to build lean body mass? Your answer to this question matters when it comes to choosing your training approach. The optimal approach for maximizing strength is different than the one you use to build lean body mass. Here’s how the two differ and why.
Building Strength versus Lean Body Mass
If your goal is to build strength, a low number of repetitions (2 to 5 reps) using a weight between 90 and 100% of your one-rep max works best. Using near-maximal weight maximizes the amount of tension your muscles are placed under during each repetition – important for maximizing muscle strength. Using heavy weight and a low number of reps also increases muscle size, but it isn’t the most effective strategy for increasing muscle size.
To maximize muscle size, choose a weight that’s 65 to 85% of your one-rep max and do 6 to 12 repetitions. Why is this best? When you do a low number of reps using maximal weight your muscles are under tension for a shorter period of time, often too short to generate the “metabolic stress” they need for maximal growth. According to Brad Schoenfeld, author of the Max Muscle Plan, metabolic stress, muscle tension, and muscle damage work together to boost muscle growth. When you do a low number of reps, even if your muscles are under maximal tension during each rep, metabolic stress is minimized. This limits your muscles’ ability to increase in size.
Increasing the amount of TIME your muscles are under tension is important for creating the metabolic environment your muscles need to grow larger. That’s why a moderate amount of weight and a moderate number of reps works best for hypertrophy.
There’s a Limit to How Light You Can Lift and Maximize Muscle Growth
When you lift lighter weights, 60% of your one-rep max or less for 16 or more reps, your muscles spend more time under tension – enough to create metabolic stress – but the tension generated with each rep isn’t enough to activate your fast-twitch muscles. In this case, muscle endurance or the ability to lift lighter weights a greater number of reps increases over time. This will make your muscles more resistant to fatigue, but you won’t get significant muscle hypertrophy or growth. To get the most muscle growth, you need a balance between muscle tension and metabolic stress. Lifting heavy but not maximal for a moderate number of reps (8 to 12) strikes this balance. In Xtrain you stay in a rep range that blends both muscle endurance and hypertrophy into the workout program. For example; In Burn Sets you reduce the reps to 10 so that you get just the right amount of hypertrophy while in Xtrain Chest/Back/Shoulders you do up to 16 reps which bring more focus on endurance.
How Much Rest Between Sets?
If your goal is to build primarily strength, longer rest periods, 3 minutes or so, between each set allows your muscles to completely recover so you can exert maximal muscle tension on the next set for greater strength development. This is what we do in the third mesocycle of STS which focuses on building strength.
For muscle hypertrophy and growth, moderate rest periods of at least 30 seconds to two minutes allow some but not complete recovery. Because recovery isn’t complete, your muscles don’t completely clear lactic acid and other metabolites that build up during a set before you do the next one. This puts your muscles under greater metabolic stress. The result? Greater muscle growth.
Very short rest periods, less than 30 seconds, aren’t optimal for muscle growth because your muscles are still fatigued from the previous set so you won’t be able to generate as much tension. The ideal formula for muscle development is to lift at 65 to 85% of your one-rep max for 8 to 12 reps, until fatigued, with rest periods between sets of 1 to 2 minutes.
Other Tips for Building Lean Body Mass
Some research shows similar increases in muscle size with one set as with three sets – and for strength-building, a single set gives you an advantage since you’ll maximize your effort when you’re doing a single set. For muscle hypertrophy and development, two to four sets may offer a slight advantage over a single set.
Doing a greater number of sets during a training period is beneficial for growth – this doesn’t mean you should train the same muscle group two days in a row. Your muscles need at least 48 hours for repair. Training before damage is completely repaired will limit muscle growth.
The Bottom Line?
The training requirements for building strength and hypertrophy are different. To build lean mass you need to place your muscles under tension while stressing them metabolically. You can do this best with moderately-heavy weight (65% to 85%), moderate reps (8 to 12), multiple sets of each exercise with rest periods of between 1 and 2 minutes between sets.
The Max Muscle Plan by Brad Schoenfeld. Human Kinetics; 1 edition (September 19, 2012)
Medicine and Science in Sports and Exercise. Supplement 30(5); 116 & 165, 1998.
Powers, Scott and Howley, Edward (2003), Exercise Physiology. McGraw Hill.
Fitness RX for Men. January 2013.
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