By Elliot Fisher MS, ATC, CSCS, PES
When trying to gain muscle (muscle hypertrophy) there are two main mechanisms: mechanical tension and metabolic stress. In this blog, we will focus on metabolic stress.
Metabolic stress, also known as metabolite training, refers to when you get a pump in the gym, feel the burn in the muscle, and when you are physically accumulating blood, lactate, and other metabolites (inorganic phosphate, and H+) into the muscle.1 This increase in metabolites can increase fiber recruitment, elevate hormonal responses, alter myokine production, accumulate ROS, and cause cellular swelling.1
This can be accomplished through a number of ways. First, it is noted that 15-120 seconds of training tends to be the best for accumulating metabolites.2 One method could be just to do an exercise with a weight where you start to feel the burn in that time range. Also, you can try using supersets, drop sets, or kaatsu training.
Supersets are when you take two exercises and do them back to back. This is typically defined as two opposing muscle groups, whereas if you work the same muscle back to back it is typically called a compound set.3 However in practice, I personally and most coaches just refer to any two exercises back to back as a superset regardless if it is the same muscle or antagonistic muscles. When doing this, I recommend either doing a light to moderate weight until you feel the burn then doing the next exercise, or doing the exercises for 1 minute each, then take 30-60 seconds rest and repeating. The benefit to the second approach is you can take a slight break during the minute to rest and then go again, possibly being able to accumulate even more metabolites than just 1 set until it burns. Another consideration I like is to do a more difficult exercise followed by an easier exercise. This often looks like an isolation exercise followed by a compound exercise. For example, dumbbell side raises for 1 minute, followed by dumbbell upright rows for 1 minute. You can’t do dumbbell side raises forever but if you switch to upright rows you can handle a lot more reps.
Drop sets can also be done to accumulate metabolites. To do a drop set start with a moderate weight and lift until you start to feel the burn or hit muscular failure. Then immediately switch to a lighter weight, probably about 25-50% lighter (this is an arbitrary recommendation, just choose a weight that is light enough that you can bang out some more reps to add to the metabolite production). This can be done for as many sets as you want, meaning you could do this for 3 drops in weight, or 10, whatever gets you the best burn.
The final method to creating metabolic stress is kaatsu training. This is more commonly referred to as blood flow restriction training or occlusion training. To do this a tourniquet is placed around either the arms or legs at a tightness of about 7/10 perceived tightness.4 The theory behind this method is that as you lift you will accumulate metabolites, but the band will disrupt blood flow enough that the metabolites will not be able to return to general circulation, making it much easier to accumulate them in large amounts. Traditionally kaatsu training is done at about 20%-50% 1RM (lighter than normal metabolite training) for a set of 30, followed by 3 sets of 20, leaving the tourniquet on in between sets.5 However you could do any rep scheme you want as long as you are getting a good pump and burn in the muscle.
When trying to use metabolite training as a method for muscular hypertrophy there are a myriad of methods to induce a good pump/burn. These include supersets, drop sets, and kaatsu training. However, any other form of training that induces a good pump can induce large amounts of hypertrophy.
- Schoenfeld, Brad. Science and Development of Muscle Hypertrophy. Human Kinetics, 2016.
- Robbins, Daniel W., et al. “The effects of load and training pattern on acute neuromuscular responses in the upper body.” The Journal of Strength & Conditioning Research 24.11 (2010): 2996-3007.
- Haff, G. Gregory, and N. Travis Triplett, eds. Essentials of Strength Training and Conditioning 4th Edition. Human kinetics, 2015.
- Luebbers PE, Fry AC, Kriley LM, Butler MS. The Effects of a Seven-week Practical Blood Flow Restriction Program on Well-trained Collegiate Athletes. J Strength Cond Res 2014;28(8):2270-2280.
- Yamanaka T, Farley RS, Caputo JL. Occlusion training increases muscular strength in division IA football players. J Strength Cond Res 2012;26(9):2523–2529.