Horizontal Jumping 101
By Cameron Gary
Running and jumping (along with lifting and throwing) are the most fundamental of human athletic movements. The Olympic Motto of “Citius, Altius, Fortius” (faster, higher, stronger) illustrates the applicability of these basic performance attributes. However, to avoid digressing into a history lesson, suffice it to say that in sprint/jump training we strive to develop all athletic performance attributes to some extent.
What could be more basic to sport than running and jumping? I guess that is why the sport of Track & Field is called “Athletics” in most other parts of the world. Running and jumping are two very closely related movements/disciplines. In a later installment I will specifically focus on that relationship. However, in this article we’ll look at the basics as they relate to jumping in general and horizontal jumping (long jump and triple jump) in particular. I hope this article will provide some insights into these basic movements so you can help your athletes develop their athleticism to their highest levels.
I understand the readers of this article represent various levels of experience and technical sophistication. Although I have a reasonable technical understanding of the jumps, I am a “plain speaking” kind of fellow. I don’t claim to be a biomechanics expert (as I most certainly am not). I am just a guy who has practiced/coached these events for a little while. I’ll progress through the technical aspects from the most basic to the more advanced levels. Please forgive me if the basics review does not excite some of you. But I want to make sure this information is palatable to everyone – rather than just a select few. That being said; I only teach what I know. Hopefully, I know what I teach.
Jumping is simply a fast, coordinated extension of the hips, knee(s) and ankle(s) in order to quickly push one’s center of mass away from the ground far enough that the feet break contact with the ground (“foot release”). This three-phased extension is sometimes called a “triple-extension” movement, or as noted mechanics expert Geoff Dyson says, a “summation of forces” (see inset). It is important to understand that one needs all three forces working together in order to have an efficient jumping effect! Any doubts? Try jumping without extending the feet (or knees, etc.) and it will be quite evident how limited your jumping will be. Of course there are other more complex dynamics (countermovements, stretch-shortening cycles, etc.) to be accounted for; but basically the “tripleextension ” is the key. One can attempt all the advanced skills one wishes; but if one does not triple-extend; one will not jump!
For our purposes there are basic assumptions we have to make. They are not capricious, as they are based upon known and proven scientific principles. Below are some terms that will help establish a common language. A basic understanding of these terms will help one to grasp the underlying concepts that govern athletic movement. Again, forgive me if you already know this; but I have to make sure everyone is on the same page.
- Force is something that tends to cause a change in the state of motion in a body
- Force may move a body at rest; or it may slow or stop a body that is already moving
- Gravity is a force
- Gravity is a magnetic force that constantly pulls all physical bodies toward the center of the earth.
- All falling bodies, regardless of weight (aerodynamics notwithstanding) fall at the same rate of speed – approximately 32 FPS².
- Jumping is simply a battle (albeit short-lived) against gravity – What goes up must come down!
- Sport performance is dependent upon an athlete’s ability to control their body and/or implements while “cheating” gravity
Center of Mass (COM)
- The center of mass is the point where all of the mass of a body is centered. A simple example is the balancing of a ruler at the six-inch mark.
- The “mass” of a body is the amount of material of which it is made.
- Mass is NOT the same as “weight”. The latter is the force of attraction between a body and the magnetic pull of gravity. For example, the moon is approximately one-seventh the size of the earth, so it’s gravitational pull is approximately one-seventh the amount of gravity on earth. If one weighs 210 lbs on the earth, one would weigh about 30 lbs on the moon. However, your mass hasn’t changed!
- The center of mass can be a point in space – for example, a doughnut. This is important in relation to human bodies since they tend to move around a lot – consequently a human’s center of mass is not fixed. It is dependent upon the position of the body/limbs. This is very important to understand!
- Speed is the rate of motion of a body.
- Speed is measured in units of length and time – for example “Miles per Hour”, “Feet per Second”, etc.
- Velocity is the rate of a body’s speed in a particular direction.
Consequently, one must have speed in order to develop velocity. For example, a sprinter uses a combination of horizontal and vertical velocity components in order to move forward. Both forces are necessary relative to one another in order to produce a resultant velocity.
- Acceleration is the rate of change in velocity
- An increase in velocity is called positive acceleration. A decrease in velocity is called negative acceleration or deceleration
- Speed is not the same as acceleration
- It is possible to increase speed while decreasing acceleration. A 100-meter dash start is a classic example – in the first strides the sprinter moves from a zero velocity state into an explosive running stride. The stride lengths and the resultant velocity will increase for approximately six seconds, but the change in velocity decreases with each successive stride – even though the athlete is running progressively faster.
- Inertia is the resistance to a change in motion.
- A resting body tends to stay at rest unless something acts upon it to cause it to move.
- The converse is true for bodies that are moving, so a moving body tends to stay moving, unless something acts upon it to cause it to stop. However, it is important to keep in mind that gravity is a constant force that works on all bodies.
- Momentum is the product of mass and velocity (Mass x Velocity or “MV”) and is figured mathematically. If either mass or velocity is altered, the resultant momentum (product) changes.
- Everything that moves has momentum. In order to generate momentum one must overcome inertia.
- A person weighing 200 lbs is needs more force to cause one’s self to move than a person weighing 150 lbs. However, once the larger person is moving, it is easier to sustain velocity and harder to stop (greater momentum) than a smaller person moving at the same speed.
- Impulse is the momentum change produced in a body. Essentially a change in direction.
- Impulse is a product of the amount of force produced versus time.
- A large force produced quickly is what we commonly think of as “power”.
This is contrasted with “strength”, which is simply the absolute amount of force produced regardless of time.
Counter- Movement Jumping
A second basic type of jump is called a “counter-movement” jump. In this case, the athlete quickly drops thier weight downward, and then reverses the direction of the movement (in this case down, then up) in order to propel the COM away from the earth. An example would be a volleyball player that quickly drops into a modified squat position and then immediately jumps upward in order spike or block the ball. This effect is at times called the “ballistic-reactive” effect, as it incorporates two distinct, yet related phases. They must be done quickly. The phases are:
1. Absorption (ballistic) – Eccentric Muscular Reaction; the dropping downward
2. Explosion (reactive) – Concentric Muscular Contraction; the exploding upward
For our purposes, we are concerned primarily with counter-movement jumping. In fact, we take this type of jumping to a higher level by incorporating training methods that increase the eccentric or “loading” phase. The hopeful result would then be to increase the subsequent response in order to produce a stronger concentric or “explosive” reaction. I will explain this concept in more detail below, but this is the type of jumping that is most useful for sprint/jump athletes. It is also the reason why counter-movement weight lifting exercises such as the Power Clean, Jerks, and Snatch are productive.
Plyometric/Stretch-Shortening Cycle (SSC)
Now for the fun stuff! The SSC is the ballistic-reactive process that occurs when one causes a shortening muscle to lengthen. This is analogous to a rubber band pulled between two fingers – although it is lengthening, it is always “trying” to shorten. I will use the analogy of a rubber ball bouncing when dropped onto a hard floor to explain the SSC, as it is most applicable to sprinting and jumping. This is how it works…
When the ball is dropped (or projected, rolled, etc.) force is applied to it to cause it to move. The ball has mass and velocity, thus it carries momentum. As long as the ball is moving it carries kinetic energy (residual force applied for it to continue to move). In this case, gravity is applying the force.
As the ball strikes the floor, the surface does not give way to the kinetic energy stored in the ball. The floor absorbs very little if any energy, so the energy carried in the ball cannot continue downward. This energy is forced back into the ball in a direction perpendicular to the surface of the floor (relative to the angle it is struck). This “rebound” energy is thrust away from the floor and subsequently into/through the ball. The top of the ball is still moving toward the floor the instant the bottom of the ball stops moving. After energy propelling the bottom of the ball has changed direction and started moving upward, the top of the ball is still moving downward. Of course the difference in time is very minute – but there IS a difference.
These opposing forces cause the ball to change shape and expand outward in order to accommodate the energy moving within the confines of the ball’s outer layer. This “extra” kinetic energy is briefly stored within the ball. This is analogous to the way a polevaulter’s pole bends upon striking the box (keep this in mind). Of course the ball immediately exerts an opposing force to resume its normal shape. The contained energy is forced back toward the opposite end where there is the least resistance (top of the ball). As nothing other than gravity opposes this energy transfer, the ball is projected (or bounced) upward.
You are probably asking, “What does this have to do with sprinting/jumping?” Read on, grasshopper, read on…
When the SSC is utilized in training the sprints and jumps, we train to become a “rubber ball”, more or less. We cause the shortening muscle to quickly lengthen during the eccentric phase in hopes of eliciting a more powerful impulse and resultant concentric muscular contraction. This intense “Stretch-Reflex” response is very fast and powerful relative to the size of the involved muscle. We endeavor to make ourselves more like a “super” ball (remember those?) so we can “bounce” even higher/faster. This explains why one can run faster on asphalt than on soft sand while expending the same amount of effort. The former simply returns more energy than the latter.
Strength vs. Power
Maximum jumping height/distance DOES NOT come from an excessive bending of the knees or “pressing” harder into the ground. “Pressing” is simply TOO SLOW! To jump higher/farther, you have to jump FASTER! The jumps and sprints are “active” movements. We want to increase absolute strength, but not at the expense of dynamic jumping power – especially “impulse”. Absolute strength is about quantity of force. Dynamic “power” is about quality of force. As power is a function of strength versus time, we have two paths to take; 1) increase the amount of strength we can exert within a given amount of time, or 2) utilize the available strength we possess as quickly as possible. This is an individual decision that depends upon the athlete’s goals and physical capabilities. But the bottom line is that we must seek to maximize the qualities of force. We must never forget this.
There is one possible exception to this concept – the stationary sprint start. The dynamics are a little different because the athlete starts from a static position. In that case, the athlete needs to generate a large quantity of force into the blocks, and then the ground in order to overcome inertia and start the body moving down the track. This is why the development of sprint power should be first in your order of business. One can’t maintain speed one hasn’t developed it in the first place. Early in the race, the proportion of time spent applying force into the ground is relatively long (higher strength requirement). But after the body is moving and maximal velocities are approached, the key to sustaining one’s momentum is to maximize the impulse imparted into the ground. One does this by causing higher ground-reaction forces (“striking” the ground harder and faster). The athlete does not try to run faster by “pressing” into the ground. Instead, the athlete strives to generate a quicker “bouncing” impulse at the correct angle of projection for sprinting (using correct sprint mechanics). Never forget that sprinting is a series of continuous jumps!
For more on jumps: Boo Schexnayder’s Horizontal Jumps Training Program