Alactic Capacity: What It Is and Why Athletes Need It

Understanding alactic capacity and knowing how to increase it will help athletes dominate on the field. STACK Expert Jesse Irizarry relates the basics.

Alactic Capacity

Conditioning is a broad term that can be confusing. Running a quick mile without getting winded does not necessarily prepare an athlete to perform well on the football field, soccer pitch or hockey ice. Running is not the kind of sport-specific conditioning you need to chase after the ball or puck for the entire game.

Understanding the Energy System

Athletes in these sports need a good aerobic base, which they can develop through continuous running (for instance, the mile run.) But they also need to develop their alactic capacity, which is the basis for sport-specific conditioning.

Loosely defined, the alactic system provides the immediate energy you need for high-intensity movement—think sprinting after a ball or jumping over a defender. It is responsible for what is called high power output.

Both the power (how fast you can use the energy) and the capacity (how long your body can produce energy for sustained high-intensity movement) come from the alactic system.

The Weight Room: Another Place for Sport-Specific Conditioning

To develop their athletes' alactic power and capacity, most coaches have them perform repeated Sled Sprints or full-speed Sprints over relatively short distances. If the exercises are done correctly, the athletes take adequate rest between sets so they can practice and learn to repeat high-intensity efforts. The key is to make sure the athletes rest just enough to run with the same speed, power and effort every single time without tiring.

What many coaches do not realize, however, is that alactic capacity can be developed in the weight room, through compound lifts using multiple sets of low repetitions (1-3) with the right amount of rest between sets.


To train for alactic capacity in the weight room, you need enough weight to increase your ability to sustain high-intensity movement. Start with 80 percent of your max in a given lift and progress heavier each week.

You can use Squats and Presses for this purpose. After warming up, load the bar to 80 percent of your actual or estimated max and perform the first set of two repetitions. Immediately rack the bar, rest 30 seconds and perform another two reps. Repeat this for multiple sets. The goal is to do as many sets as your ability and experience will allow, conditioning you to produce the same amount of force and power over and over.

Rest for 30 seconds—enough time to perform the next set safely and maintain your power output, while challenging your capacity.

Five sets of two repetitions with 30 seconds rest is a good starting point and will be challenging. As you progress over a few weeks, increase sets or weight. But add only one at a time.

Keep the repetitions per set to three and under, because your goal is speed of movement and power output. You cannot accomplish this with higher repetitions.

Break down the workout into two days. Use Day 1 for a basic compound lower-body lift such as the Squat, and use Day 2 for a Press specific to your needs. After the main lifts each day, complete assistance work for overall muscle development and balance. For example, after doing the Squat on Day 1, perform Lunges and Romanian Deadlifts with higher repetitions suitable for building muscle (6-10 reps). After this, do ab work. Likewise, you can do assistance work such as Dumbbell Bench Presses and back work like Rows and Pull-Ups after the main pressing lift on Day 2.

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