On July 27, 2020, after multiple attempts at testing my vertical jump, my maximum standing vertical jump height was just under 25 inches (63.5 cm). 6 months later on January 25, 2021, I tested myself again and achieved a 35-inch (88 cm) vertical jump. Here, I will explain what, within those 6 months of training, I did to increase my vertical jump by 10 inches.
 

Motor Potential

 

To jump higher, step one would be to increase your motor potential. Imagine jumping in a room with a low ceiling. Your ability to jump would be limited due to the constraints of the room. If you moved to a room with a higher ceiling, you could now jump higher than before. For a high-intensity movement like the vertical jump, the higher an athlete’s motor potential, the higher their ceiling for force production and explosiveness. Motor potential can be enhanced in two different ways: 

 

1. Raising Your Maximal Capacity to Produce Force

 

Force production in all athletic movements is, in part, dictated by the maximal force-producing capability of the muscle fibers being recruited for the action. Muscle fibers are often split into two broad categories based on their contractility speeds: slow-twitch muscle fibers and fast-twitch muscle fibers. Slow-twitch muscle fibers, called Type I fibers, are resistant to fatigue, recover quickly, contract at slower velocities, and are used for lower-intensity, long-duration movements. Think of jogging, swimming, and biking. Fast-twitch muscle fibers, most commonly Type IIA and Type IIx fibers, take longer to recover, contract more forcefully at greater velocities, are larger than type I fibers, and are used for short-term, highly-intense activities. Think of sprinting, jumping, and tackling. As jumping is a short-duration explosive movement, it needs as much contribution from the fast-twitch muscle fibers as possible. 

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By training according to the demands of the athletic movement you are trying to improve, the positive adaptations received from training will be more catered towards improving that specific movement and those that are similar to it. To improve a short-duration, high-intensity movement like the vertical jump, training with short-duration, high-intensity exercises is necessary. One study found that short-distance (30-80m) maximal sprint training at 90-100% effort may increase the proportion of fast-twitch muscle fibers. Another study found that weightlifters who consistently train using heavier loads (80-95% 1-rep max) experience preferential hypertrophy of fast-twitch muscle fibers when compared to those who consistently lift at lower intensities. When training to improve a maximal-effort movement like the vertical jump, it is best to train maximally.

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To increase the capacity for force production within a muscle fiber, hypertrophy of the muscle fiber is necessary. In the first few weeks of resistance training, significant improvements are mainly obtained from neurological adaptations like enhanced motor unit recruitment ability and improved coordination (study). The physical body doesn’t change much at first, but athletes still experience initial increases in strength. After 3-5 weeks, increases in strength are led more by increases in muscle size (study). For the vertical jump, my plan was to lift heavy with low repetitions and long rest periods to stimulate positive fast-twitch muscle fiber adaptations such as improved fiber recruitment and hypertrophy. 

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For those 6 months, my resistance training sessions consisted of a “main” lift, which would be the most physically-challenging and highly-intense exercise performed in the workout. This could be a back squat, split squat, or, in my case, the trap bar deadlift. I trained 2-3 times a week, with two high-intensity, heavy lifting days and one recovery day where I wouldn’t lift heavy. Each training session was a full-body training session. After warmup sets, I would perform 3-4 working sets at around 85-90% my max with a strict 4 repetitions each set. Each working set was done with the same weight used during the first working set and I’d provide myself 3-4 minutes of rest after the set. After the trap bar deadlift portion of my workout, I would perform other accessory upper-body and lower-body exercises such as the bench, landmine press, and RDL. At the start of the program, I could only manage 365 lbs for 4 repetitions. This would translate to a 405 lb 1-rep maximum. Each week, I would slowly increase the working set weight by 2.5-5% or 10-20 lbs. After a couple of months, I capped out at 445 lbs for 4 reps before attempting my 1-rep max on the final training day. Every third or fourth week, I would stagnate or reverse back down to a lower weight to allow my body to recover, one week even going down 80 lbs for my working sets. By the end of the training program, I was able to trap bar deadlift 500 lbs for my 1-rep maximum, an increase of 95 lbs over the course of 6 months. This was a clear indication that the force-producing capacity of my muscle fibers, most significantly my fast-twitch muscle fibers, was enhanced through my training.

 

  2. Raising Your Maximal Speed of Contraction

 

Vertical jumping is a fast, explosive movement. Lifting heavy is important to hypertrophy your fast-twitch muscle fibers and enhance their recruitment ability for the vertical jump but high-load lifts are much slower contractions when compared to the contraction speeds of movements like the vertical jump. It may take someone 5 seconds or more to complete a squat above 95% of their 1-rep max. In contrast, it takes a person half a second to go from the initial downward motion of a max-effort vertical jump to being off their feet and in the air. For athletes who must also sprint and jump in their sport, training independently with heavy lifting often results in a slower athlete rather than a quicker one. Solely heavy lifting leads to adaptations catered towards improving longer, intense contractions rather than quick, explosive ones. To solve this issue, including sprints and jumps in training is necessary to steer an athlete’s adaptations towards the increased explosiveness they need for the vertical jump.

 

There are three different phases of any explosive movement: 

 

The eccentric phase is where the muscle is lengthened while contracting. For example, the initial downward movement of the vertical jump. This is the “absorption” portion of force development. 

 

The isometric phase is where the muscle is contracted while its length is not changing. This is the split-second transition between eccentric and concentric contractions, between going down and up. 

 

And finally, the concentric phase. This is where the muscle is shortened and force is produced. This is the powerful upward movement that will propel athletes into the air.

 

In sports, this dynamic happens in every movement. The more powerfully the athlete can endure force during the eccentric phase of a dynamic movement, the more powerfully they will exert force out during the concentric phase. Putting this all together we get our rate of force development. This is how much force we can produce measured over a period of time.