Enhancing Maximum Velocity - Sprint Science and Its Application

INTRODUCTION 

Simply, linear speed may be defined as the rate at which an individual changes their position from Point-A to Point-B in a straight-line fashion. Whether an individual- or team-sport athlete, or executing offensive or defensive tactics, the ability to generate high straight-line speed is considered an essential factor that distinguishes high performers from their counterparts [1]. Extensively, linear sprint speed is held in high regard by athletes, coaches and sport scientists alike due to the competitive advantage it affords in creating separation and space, to beat an opponent to a position or location.

Additionally, there is data suggesting maximum effort sprint training is an excellent training stimulus as it requires generating high magnitudes of force over short timeframes, and ultimately enhances both acceleration and velocity phase performance [1]. Lastly, strategic exposure to maximum effort sprinting is postulated to have prophylactic effects against hamstring injury due to its positive influence on fascicle length [6] and tissue resiliency specific to maximum effort sprinting [2].  

The purpose of this article is to define the velocity profile, discuss deterministic factors that underpin maximum velocity, and offer training recommendations that may aid in the enhancement of maximum velocity in linear sprinting.

DISCUSSION 

Because mechanical factors underpin linear speed, and will be briefly discussed hereafter, it is important to define velocity. Velocity is a vector that quantifies the rate of displacement and the direction displacement is occurring. Its scalar counterpart, speed, simply accounts for the rate of displacement [7]. Additionally, acceleration is the vector that specifies the rate of change in velocity and the direction it is occurring in.

Traditionally, a given straight-line sprint is broadly divided into two distinct yet interconnected stages of acceleration and maximum velocity [1]. The acceleration phase is characterized by the most rapid increase in velocity, while the maximum velocity phase is characterized by a more gradual increase in velocity where a plateau and, in many instances, a slight decrease in velocity occurs [4].

While there are several factors that have been identified as deterministic, it is important to indicate that maximum velocity in linear sprinting is largely governed by vertical and horizontal force-time variables [5]. Specifically, the demand for horizontal force is greatest during the acceleration phase due to inertia – in this case the resistance to begin movement along the sprint path – and the more angled body position (e.g. forward trunk lean and more positive shank angles) that is typically assumed at the initiation of a sprint [8]. During the maximum velocity phase, vertical force demands dominate due to the need to resist the downward influence of gravity and the more upright body position typically assumed in this phase of sprinting [8].

When plotting an individual’s velocity over a given distance a velocity profile may be generated [1,4]. Velocity profiling can be an effective method of illustrating an athlete’s capability to change their position over a period of time. Considering the sprint time and sprint distance of individual velocity profiles, coaches are able to train athletes to optimize phase-specific mechanics, and thus improve sprint capabilities that may exploit advantageous opportunities during competition. 

The importance of an athlete’s unique velocity profile largely lies in the demands of their sport. For example, the velocity profile of a 100 meter sprinter will most likely differ from that of a field- or court-based athlete. 

[Figure 1] 

A typical profile of a 100 m sprinter could be characterized by a more gradual increase in acceleration over a given distance followed by reaching a higher maximum velocity and maintaining that velocity longer. It is proposed that these athletes often do possess the technical efficiency required to attain a longer acceleration phase and better maintenance of maximum velocity due to a high devotion to training time to sprinting technique. One should also consider the largely non-reactive nature of the 100 m sprint, coupled with a longer distance allowing them the opportunity to accelerate to and maintain maximum velocity.

In contrast, the velocity profile of a team-sport athlete, for example basketball, demonstrates a short-lived acceleration phase with a more abrupt arrival to maximum velocity. Following the peak, team-sport athletes tend to display greater decreases in velocity. It is proposed that these athletes often do not possess the technical efficiency required to attain a longer acceleration phase and better maintenance of maximum velocity analogous to their short-track counterparts. One should also consider the more reactive nature of team sports (e.g. frequent changes in sprint directions), coupled with environment constraints (e.g. field or court dimensions and the number of individuals on offense and defense) often do not afford the opportunity to accelerate to and maintain maximum velocity.

Nonetheless, key mechanics of the maximum velocity phase are upright posture with neutral hips and minimal backside swing after toe-off; “high thigh” frontside recovery before touchdown with aggressive, synchronized thigh action; and a more upright shin at touchdown [3] – which can be encouraged by cueing “Up, Scissor, Bounce and Strike”.

PRACTICAL APPLICATION

Now that velocity profiles and their underpinning factors have been established, training recommendations may be offered to encourage the enhancement of maximum velocity in linear sprinting tasks.

When seeking to enhance linear sprint speed, it is imperative to ruminate, and emphasize, kinetic and kinematic (i.e. mechanical) factors that underpin faster sprint performances. At ATH mechanical factors considered when training sprint ability are ground contact time, and equally importantly, force application. Similarly, the ability to produce and maintain postures and positions coupled with efficient transitions between each is of importance. 

Exercise selection

At ATH technique training is seamlessly incorporated into the dynamic warm-up to improve relative strength required to create and maintain postures in sprinting. Having athletes finish movements such as a squat or lunge in a sprinter’s stance (i.e. tall trunk, knee even with hip and toe dorsiflexed) is an excellent method of developing stability, balance and correct motor patterns needed [Video #1].

To further develop proper postures, the “scissoring” of the thighs and stiffness at touchdown, straight-leg mechanics may be used either in a static position or dynamically (i.e. moving forward). Additionally the A-series may be used [Video #2]. 

When seeking to develop the cyclical aspect of maximum velocity sprinting, dribbles or step-overs may be used to encourage the “knee-up, heel-up, toe-up” and horizontal strike associated with transitioning from toe-off to swing phase to stance phase [Video #3].

Additionally, bounding will offer a neuromechanical overload to improve sprint-specific force generation, absorption and utilization. 

Training volume

Athletes training volume is determined by the accumulation of drills and exercises trained. It is important to note that ‘at-speed’ intensities (~95%) are important for athletes to develop faster speeds. Generally, a 1 minute rest for every 10 meters sprinted is recommended. This rest time can be passive or active – standing or holding a sprinter stance (i.e. 3-bucket pose for 10 seconds each leg), respectively. These higher intensity tasks can be coupled with lower intensity tasks to allow teaching opportunities to further improve form.

Training frequency

It is recommended the frequency of maximum velocity training to occur at least once a week, but limited to 3 times a week to attenuate fatigue. Dependent on the sport and the need to train maximum velocity, drill and exercise volume will influence how often sprint training occurs. 

For instance, a sprinter may complete 4-5 sprints for 40 yards, focusing on improving technical characteristics (i.e. posture, leg recovery, ground contact) per repetition, while a team-sport athlete may spend less time improving minute details of technical characteristics. 

References

1. Clark KP, Rieger RH, Bruno RF et al. The national football league combine 40-yd dash: how important is maximum velocity? Journal of Strength and Conditioning Research. 33(6):1542-50, 2019.
2. Edouard P, Mendiguchia J, Guex et al. Sprinting: a potential vaccine for hamstring injury? Sports Performance and Science Reports. 48(1):1-2, 2019.
3. Gamble P. Comprehensive Strength and Conditioning: Physical Preparation for Sports Performance. [Book reference]
4. Healy R, Kenny IC, Harrison AJ. Profiling elite 100-m sprint performance: the role of maximum velocity and relative acceleration. Journal of Sport and Health Science. 00:1-10, 2019.
5. Mero A, Komi PV, Gregor RJ. Biomechanics of sprint running. Sports Medicine. 13(6):376-92, 1992.
6. Mendiguchia J, Conceição F, Edouard P et al. Sprint versus isolated eccentric training: comparative effects on hamstring architecture and performance in soccer players. PLoS ONE. 15(2):e0228283, 2020.
7. Rodgers MM, Cavanagh PR. Glossary of biomechanical terms, concepts, and units. Physical Therapy 64(12):1886-902, 1984.

8. Wilkau HCL, Irwin G, Bezodis NE et al. Phase analysis in maximal sprinting: an investigation of step-to-step technical changes between the initial acceleration, transition and maximal velocity phases. Sports Biomechanics. 19(2):141-56, 2020.