The missing piece to your workout could be your rest interval. Far too often, rest intervals go unmonitored leading to inconsistent time between sets (47 seconds here, 6 minutes there) yet it is very crucial to 1.) matching the appropriate energy system your body uses to the type of exercise you’re doing 2.) influencing your body’s adaptation toward your training goal whether it’s strength, power, hypertrophy, or endurance and 3.) keeping you on track to utilize the precious time you have in the gym efficiently and effectively.
Here’s a crash course in the bioenergetics of exercise:
Your body needs ATP as a source of energy to do anything, whether it’s running a marathon or using your thumb to send a text message. Your body can make ATP using different energy systems. Of these energy systems, some require oxygen, and some don’t (aerobic vs. anaerobic). Your body uses aerobic energy systems for activities that are low in intensity but long in duration whereas anaerobic energy systems are used for activities that are high in intensity but short in duration.
Rest intervals are assigned to particular training goals. The training goals are determined by the intended intensity and duration of the activity which relates back to the nature of the energy system used during that type of training.
For example, if your training goal and activity is strength training, the energy system your body uses to make ATP needs about 2-5 minutes between sets to “recharge” its ATP-making capacity. A rest period shorter than that can lead to a hindrance in your performance, which leads to you not making the progress you could be making.
When rest intervals aren’t managed, there can be disconnect between the intended training goal and the actual training that’s taking place. When you do strength activities which are high in intensity and short in duration but only give yourself a short rest interval, your body begins to interpret your activity as something else which will interfere with the adaptation and progress your body makes.
Even with all that aside, many people find themselves at the gym looking at the clock, and realize they have about 30 minutes of training left but only 15 minutes left before they have to leave. To compensate, the gym goer omits half of what they planned to do and rushes through the rest of the workout. It’s easy to see how that can also lead to suboptimal performance and progress.
There is a simple solution: keep track of your rest intervals. Most phones have a stopwatch function, but I find it more deliberate to use a wrist watch or even a pocket stopwatch to manage this. Have a firm understanding of what your training activities and goals are, and apply the appropriate rest intervals. When you manage your rest intervals, your training will undoubtedly become more effective and efficient.