In the context of athletics, speed is best defined as the “rate of performance” of an activity. This can refer to any movement or action. In athletics, the velocity at which one executes a movement can be the difference between success and failure. Speed is a culmination of reactive ability, rapid force development, rapid force application, and effective movement technique. Generally, when the force demands of an activity increase, the velocity output of the movement decreases (1) as demonstrated by the force-velocity curve (Fig. 9.1). The goal of a speed-training program is to move this curve up and to the right, which would mean being able to create greater force at higher Speed This, in combination with an ability to maintain biomechanically advantageous body and limb positioning, creates an increase in the velocity of movement. Speed of movement greatly affects an athlete’s abilities in regards to linear speed, agility/MDS, and quickness. The following are essential components of a well-designed program to improve
speed of movement:
Stability, strength, and power
Muscle and joint elasticity
Joint mobility and flexibility
STABILITY, STRENGTH, AND POWER
Stability, strength, and power training help shift the force-velocity curve up and to the right (2). While stability training develops appropriate balance, strength training improves the body’s ability to create force, and power training aids in decreasing the amount of time needed to create that force. These all have significant contributions in regards to improving speed. When performing stability, strength, and power drills specific for speed development, it is important to include exercises for contributing areas, such as the feet, anterior and posterior muscles of the shins, the core, and hip flexors/extensors as part of a whole-body program. In addition, movements that emphasize powerful plantar and dorsiflexion of the ankle, as well as extension and flexion of knee and hip are also important components.
MUSCLE AND JOINT ELASTICITY
Ballistic movement, as found in speed, agility, and quickness training, is created by a forced and rapid lengthening of a muscle immediately followed by a shortening of the muscle, creating an elastic “rubber-band-like” effect of energy release. As mentioned in Chapter 8, this ability to store and release energy is referred to as the stretch-shortening cycle and is affected by the intrinsic qualities of the muscle and the involved musculotendinous junctions (2). This action is often reflexive, and referred to as the “stretch reflex.” Training the muscle and tendon’s ability to load eccentrically and rapidly release energy concentrically improves the magnitude and effectiveness of the stretch-shortening cycle (2). This is achieved through power training and plyometrics.
JOINT MOBILITY AND FLEXIBILITY
Joint mobility is the ability of a joint to move through its natural, effective range of motion and is further characterized as the balance of strength and flexibility regulating contrasting motions around a joint (i.e., flexion and extension). In addition, the integrity of the muscle tissue and its ability to relax and contract appropriately during movement is a limiting factor in producing effective joint mobility. For example, when a sprinter comes out of the blocks, proper range of motion during hip extension requires strength of the hip extenders, as well as the ability for the hip flexors to lengthen properly to allow for full hip extension (Fig. 9.2). If there is an imbalance of strength and flexibility about the hip, range of motion will be compromised, which will in turn affect force output and speed of movement. In addition, if the muscle tissue is not responding properly due to injury, adhesions, or other factors, performance will be diminished. This can be improved with flexibility training.