Plyometrics are probably the most interesting part of athletes workouts. Or at least, the flashiest. It’s alluring to think that trying an advanced secret variation of an explosive jump that you saw on a youtube video of an MMA fighter (or professional dunker, or any other high level athlete) will morph you from Clark Kent into Superman.
Rate of force development (RFD) can be broken down into two stages. There is an early stage rate of force development and a late stage rate of force development. Early stage RFD is typically measured from 0-100 ms while late stage RFD is anything after.
Importance of Early Stage RFD
Sporting movements are often required to be fast, reactive movements that occur over a small amplitude. For example a large countermovement jump can take between 500-1000ms, while a squat jump with no countermovement may take around 300 to 430ms (1). In sport, movement amplitude is going to be much more similar to that of a squat jump (zero to minimal countermovement) than to that of a large CMJ. At the same time, sprinting ground contact times can last as short as 100ms. With this in mind, it is easy to see how early RFD may play an important role in sporting movement, especially those covering a small amplitude over a short period of time (ranging from 100-430ms).
Frans Bosch has popularized the concept of muscle slack (Van Hooren has publications on it). It is hinges on early stage rate of force development and the speed at which the muscle, tendon, and series elastic element can go from “slack” to “tense”. When a muscle is not activated, it is relaxed and there is slack in the muscle, tendon, and series elastic element as it hangs from its origin and insertion. Bosch uses the analogy of a rope to help describe how muscle slack works. You are holding one end of the rope and the other end is tied to a car, you are the origin and the car is the insertion. Before you can pull the car with the rope, the rope first has to become tense. This is the point where the rope goes from lying slack on the ground, to now in a straight line from your hands to the car. This is synonymous with the process of the muscle fibers aligning from the origin and insertion. The second part of the slack is that the rope now needs to become tense enough so that force can be applied to the truck. At this point, the rope goes from being in a straight line from your hand to the car, to now taut, from you producing a force on the rope. This is synonymous with the muscle co-contracting to produce enough force on the tendon so the muscle can become tense. Muscle slack uptake occurs during start of where the contractile element receives the chemical signal to align all the way to the point where both the musculotendon unit and the series elastic element are tense.
The idea of measuring and training for velocity deficiencies has become popular since the recent studies of JB Morin and colleagues. In one of their studies, they examined several different subjects and based on their profiling methods, determined whether or not the individuals had a force-velocity profile that was either velocity deficient or force deficient. Once the deficiency was determined, the subjects were trained using specific methods emphasizing the velocity component of the movement (slow velocity for max force and fast velocity for speed of movement). After the study’s training cycle, J.B Morin and colleagues were able to show that the specific training methods, either slow or fast, improved vertical jump performance and overall balance of the subjects’ force velocity profiles.
Strength is contextual. In movement, force (strength) can be produce at all speeds. For example, high-speed strength means being able to produce large amounts of force at a high velocity. Slow speed strength simply means being able to produce high amounts of force at low velocities. At all times, when talking about strength, we need to make sure that the context is clarified. However, just because they are contextually different, does not mean they are not related. For example, increasing slow speed strength (one rep maxes) can help facilitate high speed strength (vertical jump height).
Being “elastic” or “reactive” refers to being able to have a good ability to quickly develop force and transfer one movement’s energy into another. The reactive strength index (RSI) is one of the most commonly used field tests for assessing these qualities. The RSI is the jump height of the movement divided by ground contact time. In other words, the higher you jump and faster you get off the ground the better your RSI will be.
Contrast training is widely used by many coaches to help with power development. It involves the usage of several exercises in series to facilitate the potentiation of the nervous system and muscular system.
In the book Special Strength Training: Manual For Coaches, written by Yuri and Natalia Verkhoshansky, it is noted that contrast training is used to help with developing more efficient motor-engrams (movement patterns). This is why the desired movement is performed last. Theoretically, the previous movements that were performed in the series were different variations of the primary desired movement. This puts the body in a “problem solving” state and teaches it to perform the primary movement (when done last) in a more efficient way. This is what I would call a “specific” contrast. Continue reading “Contrast Training (Power)”
The drop-catch method was detailed in one of my previous posts (click here). It is a method that utilizes higher velocity loading schemes and less weight on the barbell to provide an overload stimulus to the athlete. It is centered around the idea of having to rapidly absorb a high(er) eccentric velocity loads over a shorter period of time and over a smaller range of motion.
The Banded Squat Drop
The banded squat drop can be used in the squat drop progression. Obviously, the banded version would come after the body weight and barbell versions, but the methods of application are the same.