From a hierarchical standpoint, the methods for developing speed and agility can be categorized as primary, secondary, or tertiary. This scheme is largely a matter of practicality and is based on a continuum of skills and abilities ranging from special to general. The key to applying these methods lies in their skillful combination rather than exclusive or disproportionate use of any one of them.
The primary method for speed and agility development is execution of sound movement technique in a specific task. Initially, athletes should perform tasks at submaximal learning speeds to establish proper mechanics. As they progress toward mastery, task performance can approach or exceed full competition speed (23, 39, 57, 106). For execution of specific techniques, an athlete’s mechanics should target the performance criteria discussed in the previous sections.
In contrast to some skills, running is a natural activity that most athletes have experience with-correct or otherwise. On the one hand, children usually learn the rough technique of running at an early age (9, 72). To some extent, technique training can focus on perfecting form and correcting faults more than on teaching novel mechanics. On the other hand, many athletes acquire inefficient movement habits due to incorrect coaching or unfamiliarity with the advanced technique. This presents a challenge in terms of skill acquisition because it involves revising established motor programs (guidelines for teaching movement skills are presented in the "Program Design" section, p. 476).
Secondary methods of speed and agility training include sprint resistance and sprint assistance. These target the development of special skills in modified performance conditions.
This method includes gravity-resisted running (e.g., upgrade or upstair sprinting) or other means of achieving an overload effect (e.g., harness, parachute, sled, or weighted vest). The objective is to provide resistance without arresting the athlete’s movement mechanics, primarily as a means of improving explosive strength and stride length (23, 32, 39, 57, 65, 66, 97). In general, ≥10% changes in movement resistance have detrimental effects on technique (e.g., arresting the athlete’s arm and leg action in an attempt to muscle through each stride). Thus, strength and conditioning professionals should apply overload conservatively.
Sprint assistance includes gravity-assisted running (e.g., downgrade sprinting on a shallow [3-7°] slope), high-speed towing (e.g., harness and stretch cord), or other means of achieving an overspeed effect. The objective is to provide assistance without significantly altering the athlete’s movement mechanics, primarily as a means of improving stride rate (23, 31, 39, 57, 65, 66, 79, 97, 114, 130). Regardless of whether the athlete actually achieves overspeed, this method may also improve quality of effort during normal maximum-velocity sprinting by reducing the time and energy needed to accelerate. In general, apply assistance conservatively, exceeding maximum velocity by ≤10% (~1 m/s). Beyond this threshold, the athlete may tend to lean back and overstride in an attempt to brake and protect him- or herself.
Tertiary methods of speed and agility training include mobility, strength, and endurance training. These target the development of general skills and abilities.
It is important to view functional flexibility in the context of the optimal ROMs needed to perform specific tasks. During running, the hip and knee joints move through relatively larger ROMs than the ankle, which acts almost isometrically during the support phase by virtue of reflex stiffness and SSC action (1, 2, 10, 33, 38, 62, 63). The ability to fully retract the leg during recovery is requisite to achieving proper ground preparation position and subsequent ground strike. Inadequate mobility can therefore result in improper foot placement (e.g., overstriding), with longer ground contact times and higher braking forces.
If an athlete has sufficient mobility, the forces occurring within normal ROMs-rather than his or her flexibility-may determine performance or predisposition to injury. Therefore, it is simplistic to apply the notion of full range of motion to all tasks or joint actions.
Athletes can develop mobility restrictions because of imbalanced training or adaptive shortening, for example, due to inactivity or immobilization. Strength and conditioning professionals should identify such limitations and specifically address them in training. Regular flexibility training generally seems to have beneficial effects on athletic performance (77, 108) and equivocal effects in terms of injury prevention (121). Given the task-specific functions of multiarticular muscles (135, 138), it is important to assess flexibility with valid means and to use discretion when generalizing isolated joint actions to multijoint tasks.
Athletes must develop explosive strength qualities in order to maximize their speed and agility performance. This does not imply, however, that they should perform only low-resistance, high-speed movements in training. The ability to achieve high movement velocities requires skillful force application across a range of power outputs and muscle actions. For maximal transfer to athleticism, resistance training programs should progressively address the entire force-velocity spectrum (figure 17.2). This is achievable with mixed methods training strategies (22, 49, 50, 88, 109, 116, 128, 132, 142).
Strength and conditioning professionals should select and prioritize strength training tasks according to their dynamic correspondence with the target activity (109, 129, 131). Rate and time of peak force production (impulse; figure 17.1) and dynamics of effort (power; figure 17.2) are especially important criteria. Other considerations include amplitude and direction of movement, accentuated region of force application, and regime of muscular work. The keys to optimal transfer are threefold: identify the target activity’s mechanics via task-specific needs analysis, choose training movements accordingly, and distinguish between specificity and simulation of a task’s outward appearance.
Stretch-shortening cycle actions fulfill most or all of these criteria and usually deserve high priority in speed and agility training. The following is a simple classification scheme for plyometric tasks associated with SSC actions (104, 105):
- Long response-ground contact >0.25 second, large angular displacement
- Short response-ground contact <0.25 second, small angular displacement
This scheme is useful in selecting tasks to improve specific running mechanics. For example, long-response plyometrics such as countermovement or squat jumps transfer most directly to start and acceleration performance, whereas short-response plyometrics such as depth or drop jumps have more transfer to maximum-velocity running.
Further, athletic movements like running and jumping involve force transmission and summation through the kinetic chain, rather than isolation within body segments (3, 10, 53, 109, 116, 124, 135, 138, 142). For example, since the primary propulsive forces occur during ground contact, closed chain movements of the lower limb would be a logical starting point in selecting exercises to improve sprinting performance. The strength and conditioning professional might assign open chain exercises to a secondary, but still important, role. Indeed, braking the forward swing of the recovery leg in preparation for ground strike beneath the body is an open chain movement that athletes must execute properly in order to efficiently apply GRFs during the support phase.
The concept of speed-endurance originated in racing events (23, 39, 48, 49, 57, 106, 107, 115, 133, 136, 137) and is the basis of the special endurance paradigm discussed next. Figure 17.9 summarizes traditional methods for developing this quality. The athlete’s training status and the demands of his or her sport should determine the respective role of each method.
The objective of the competitive-trial method of training is to develop an athlete’s special endurance-the specific metabolic conditioning needed to perform his or her movement skills in competition or practice (22, 23, 48, 49, 109). The underlying strategy is to develop the ability to achieve a predetermined effort distribution, or a target pace or series of target paces, in training and competition. This method can be adapted to sports other than race events (87, 95, 117, 118).
Figure 17.10 outlines a procedure for establishing special endurance training criteria according to competitive exercise:relief patterns in various sports (87). This tactical metabolic training concept offers certain advantages. It economizes training time and effort by optimizing athletes’ arousal, attention, and motivation through sport skill-based metabolic conditioning drills-for example, performing a series of playbook assignments in competition-specific workloads.
It is equally important to understand the limitations of this method. Unless accompanied by telemetry data, tactical modeling does not provide a direct measure of workload intensity. The strength and conditioning professional must therefore establish target training pace(s) for the observed interval duration(s). For activities in which resistance is limited to the athlete’s body mass, one can estimate this by reversing an established method of projecting running time as a function of distance (23, 106, 136, 137)-that is, projecting running distance as a function of time, and then making empirical adjustments according to an athlete’s developmental status and workload tolerance. The energy cost can be estimated as a function of movement velocity for a variety of locomotion modes (27), thereby establishing equivalent workloads for different modalities.
Another limitation of this procedure is that tactical models based on play start-stoppage patterns may not account for the total volume of work performed in competition, especially if activity continues when play is suspended (e.g., after a score, penalty, or time-out). In general, however, this method is a pragmatic way to model special endurance training tasks on the underlying tempo of competition.