Plyometric training is a popular modality used to develop power for a range of power-dominant sports or skills requiring power, such as sprinting and jumping. Although plyometric methods can be applied to a wide range of sports, I believe they are especially relevant to skills requiring reactive strength. I discussed the importance of reactive strength to jumping performance in my last article on training vertical jump performance. The purpose of this article is to discuss the application of two specific plyometric exercises which are often overlooked: bounding and speed-bounding.
Comparing bounding and speed bounding
Bounding involves jumping from one foot to the other for maximum horizontal distance, and resembles the step phase of the triple jump. Although the athlete should be encouraged to provide an active landing with a clawing action, the landing is usually performed with a flat foot or heel contact with the ground.
Speed-bounding is similar to bounding but is performed with greater horizontal speed. This is achieved by performing a short eg. 10m approach sprint, before taking off into the speed-bound. You can see an example here. The coaching cue I like to give is to bound for distance but “hold your speed across the ground”. The outcome is that bound distance is shorter than bounding, and the landings are more active without an initial heel contact with the ground.
If you look at a biomechanical analysis of bounding and speed-bounding, you immediately and how see the key differences between bounding and speed bounding emerge, and how they compare to free sprinting.1
Finding a role for bounding and speed bounding
The table indicates that bounding is characterized by relatively long steps or strides, high forces, and long ground contact times. Because the landing involves high impact and eccentric or muscle stretch loads, bounding is excellent for the development of reactive strength, especially for jumping events such as long, triple and high jump.
While bounding more closely resembles jumping, and has some significant differences with the biomechanical demands of sprinting, I still also like it as a technical drill for the development of sprinting skill. The reason is that the intent of bounding is to jump for maximum distance, and it therefore encourages a powerful triple extension (hip, knee, and ankle), an excellent free knee drive, and powerful arm drive.
Since speed-bounding looks more like sprinting and has similar biomechanical demands, it is an excellent plyometric activity for the development of sprinting speed. It allows relatively high speeds to be achieved (like other forms of resisted sprinting), but still provides an overload to sprinting to create a training stimulus. When landing from each bound, there is a significant vertical velocity that must be decelerated, and therefore a muscle stretch load that must be tolerated in order to maintain a short ground contact time. This means that speed-bounding can be thought of a sprint-specific reactive strength exercise. It differs from other sprint-specific strength exercises like sled sprints that provide horizontally directed resistance, and therefore do not overload reactive strength.
The speed-bound index
Testing in sprinting is critical, and the same is true in bounding and speed bounding. Assessing an athlete’s speed-bounding performance can be used to:
- Provide an athlete profile to determine strengths and weaknesses
- Monitor the effects of plyometric training
- Provide a competition to motivate athletes to be better
One way this can be done is to calculate the speed-bound index (SBI)2, for example over 15 bounds. In this test, the athlete performs speed-bounding for 15 bounds from a stationary start, and is instructed to maximize the distance of each bound and also minimize the time taken to perform the 15 bounds. The objective is to get a balance between bound distance and speed.
SBI (15 bounds) = distance / time
Distance can simply be measured using a tape measure, whereas time can be measured in different ways. Using a stop watch, the coach starts the time as soon as the first movement occurs from a stationary start, and stops the watch when the foot contacts the ground after the 15th bound. Obviously timing error will be influenced by the skill of the timer, as with any hand-held timing. A more accurate approach is to record the test with video using an application such as Hudl Technique on a smart phone or tablet. The video can easily be advanced and stopped at the instant the test starts and finishes, revealing the time taken on a time scale that is displayed on the device. Doing the final calculation is easy.
Putting it together
As with any type of training, bounding and speed bounding are most effective when you understand what they do and where they fit into training. Having some measurables will help you track athlete progress and hopefully help you see how these tools can help your athletes increase their reactive strength.