For any fitness goal, there are multiple factors that must be taken into account when designing a training program. Reps, sets, intensity, frequency, training mode, etc. However, oftentimes people don’t pay much attention or don’t even ask about rest. I am not talking about rest as in recovery time or days off that your body needs, I am talking about rest time between sets and exercises. It is a factor that is often overlooked, but that is essential for optimal performance. Rest times vary and depend on goals so in this article I am going to discuss rest intervals for strength, power, hypertrophy, and endurance.
Each aspect of performance (strength, power, hypertrophy, and endurance) relies mainly upon one of the three energy systems. The difference between systems is the main substrate they use for fuel, how long they can provide the body with energy, and how long it takes them to recover to keep providing energy. So, let’s start with strength. Maximal, slow, strength is displayed when exerting maximal force in a matter of 2-5 seconds. For example, a 1RM of a squat, bench press, or deadlift. On the other hand, power is a display of a combination between force and time. It refers to how fast you can exert force, so usually activities that take 1-2 seconds. An example of power can be a 1RM of a power clean or a vertical jump. Since both, strength and power, occur quickly, they both rely on our first energy system: the phosphagen system. Our body takes all the energy required for the lift from the ATP that this system provides. In order for the phosphagen system to fully recover and replenish those energy stores, it needs to rest for 2-5 minutes. “But I have lifted multiple times without resting for that long and I have been able to improve my 1RM overtime” is what some of you must be thinking. Yes, you probably have but what I am talking about here is optimal performance. If you want to work on your strength and reach your true potential, then resting time should be kept at a minimum of 2 minutes between reps.
When it comes to hypertrophy, gaining lean body mass or muscle, the rest interval is not as long. When trying to gain muscle you usually want to work at submaximal loads doing between 6-12 reps, which means that the amount of time you spend working is longer (1-3 min). For this exercise time, you use your second energy system: the glycolytic system. This one relies on ATP that is produced without oxygen, just like the phosphagen system, so it will take the system 30-90 seconds to recover. Personally, when working with my clients I allow them to have the shortest rest time within that range because I’m not always working with the exact or accurate 1RM percentage that I want, so by reducing their rest time, I make sure I am still producing enough muscle damage.
Lastly, endurance. There are two aspects to endurance, cardiovascular and muscular. Even though they are related, the training methods are different. It is not the same to be training for a marathon, as for a maximal number of push-ups, chin-ups, or squats in a row. They both rely on our third energy system, oxidative, however, the rest times are different. Let’s discuss muscular endurance first. Since the goal is to be able to perform multiple submaximal displays of force, we need to train the body to do so by giving it very short rest times. The energy system we use for endurance does not run out of fuel as quickly as the others because it uses oxygen to produce ATP. Because we are not working at our highest capacities/intensities, we need to teach our bodies to be able to go for periods of time longer than 3 minutes. To do so, we must give our body only 30 seconds or less of recovery and make sure we are performing more than 12 reps on each set. On the other hand, when training for a marathon, you probably want to run long distances which means that the work to rest ratio needs to be 1:1. Because of the length of exercise time, the oxidative system needs an equally long period of time to recover. So if you ran 6k in 30 mins, then you need to rest for at least 30 minutes before running again. That is, of course, you want optimal performance.
So there it is, next time you are at the gym make sure you are taking enough time to rest between sets and push yourself on your work intervals. This, plus a well-designed program, should help you potentiate gains and achieve goals.
If you have any questions, please feel free to text me or send me an email.