How can we ensure our programming is context-driven?

By Andrew Hyde
Last updated: February 29th, 2024
8 min read

Introduction

Improving the competitive performance of athletes in field-based invasion sports such as football (soccer) calls for a needs analysis of the technical/tactical (21), physiological (19) and biomechanical (18) requirements of the sport. Although soccer is an intermittent sport that uses both the anaerobic and aerobic energy systems (3), this Blog Post will focus on the biomechanical and perceptual aspects of field skills in soccer. By field skill, we refer to athletic skills such as deceleration, agility and speed.

Therefore, the aims of this Blog Post are threefold 1) discuss how we can identify and program field skills 2) clearly identify and understand the field skills and 3) describe what they look like in soccer in addition to as a general technical model.

Needs Analysis

To understand what field skills occur in soccer and how these occur, we as coaches need to develop a needs analysis which is specific to the sport (e.g. soccer) and the particular playing positions on the field (e.g. midfielder or winger).

To do this, of course, we should draw on peer-reviewed literature to provide us with evidence-based time-motion data on the demand of the sport. However, to provide more context of how things actually happen, a notational analysis of a game or video clips of gameplay on YouTube can help us figure out exactly how athletic tasks are executed and the stimulus that causes these tasks to be carried out (14).

Reverse Engineering

Once this information is collected and at our disposal, we must begin with the end in mind. S&C coaches have all been guilty of losing sight of the end outcome during the decision-making processes of exercise selection for example.

If sessions support the improvement of a field skill with specificity to how it is used in game situations, it is time well spent. This is not to say general physical preparation shouldn’t be carried out, or general speed mechanics shouldn’t be taught, but that context must be applied eventually with the aim of achieving true transfer.

Once general models of field skills such as acceleration are taught, we must continue to build field skills by ensuring that the drills prescribed are integrated by athletes in sports-specific scenarios (14) and that the gym-based exercises we prescribe support the development of these field skills. It’s also important to note that the quality and context of coaching must align with these concepts too (14).

Understanding Field Skills

Field skills in soccer can be categorised into three main groups:

1. Deceleration
2. Agility & pre-planned change of direction speed
3. Acceleration & top speed

It’s important to note that despite being grouped, agility & pre-planned change of direction are completely independent skills (24), as are acceleration & speed (22).

As proposed by Jefferys (12, 13), skills can be broken down into:

1. Initiation movements – Used to start movement or change motion (e.g. Side-step motion to move laterally whilst watching play).
2. Transition movements – Used to set up a position where subsequent movement can be efficiently executed (e.g. crossover step to assume a position facing forwards).
3. Actualization movements – The final movement that determines success in an athletic task (e.g. following a transition with a sprint to beat an opponent).

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Deceleration

Deceleration is defined as a rapid stop or decrease in the body’s velocity, followed by re-acceleration in a different direction (10). This means that deceleration is a transition movement (14).

Kinematically it can be described by a centre of mass (CoM) posterior to the feet with a full foot heel strike, small steps and a wide base with knee flexion. Kinetically it can be described by high braking forces, long ground contact times, high step frequencies and eccentric muscle actions of the quadriceps and gastrocnemius (5, 1). Gradual progression in deceleration is key as decelerations high a load that is 37 % higher than accelerations per square metre (8).

Being a transition movement which precedes change of direction (CoD) and having a higher occurrence in small-sided games (SSG) (21), sessions entirely dedicated to deceleration are likely unwarranted, especially when decelerations occur 2.9x more frequently than accelerations (8).

Agility & Pre-planned Change of Direction Speed

Sprints that include a CoD precede 6 % of all goal-scoring situations in soccer (6). Even though this may appear low, players cover an average of 217 + 165 m through multidirectional sprints (4), accounting for 3.5 % of their total distance. From a time-motion perspective, players change direction every 3.8 – 4.5 seconds (3).

However, true Change of Direction Speed (CoDS) in invasion sports is rare (12), defined as a pre-planned task where “change of direction” occurs (20). Albeit, closed CoDS drills can be used as general tissue preparation to develop eccentric strength, dynamic balance and concentric rate of force development as a physical foundation to agility without a cognitive component.

This isn’t to say that developing CoDs is useless. Pre-planned side steps result in greater lateral foot placement, greater lateral movement speed, greater forward foot displacement, increased hip abduction, lower knee joint angles and reduced forces through the knee than unplanned side stepping (11). This can help us develop the physical aspects of agility.

On the other hand, agility is defined as a “rapid whole-body movement with a change of velocity or direction in response to a stimulus”. With a change of velocity being agility, deceleration alone could be performed as an offensive agility transition (24).

For example, a winger could be performing a linear sprint with the ball down the line, towards the touchline. As they approach the touchline at a high speed, they stop the ball before it goes out, decelerate past the ball and turn back towards it to cross or pass. The aim of the deceleration was to go from ‘fast to slow’ more suddenly than a defender, to create time and space to execute a pass or cross.

Acceleration & Speed

Linear acceleration and maximum velocity sprinting are soccer-specific actions which can impact the outcome of games (16). Elite soccer players average 17 m per sprint, with ~50 % being shorter than 10 m (8) and only 4 % reaching 30 m (3).

45 % of goal-scoring scenarios are preceded by a linear sprint (6). Although forwards, wingers and full-backs perform more sprints compared to centre-backs and central midfielders, there doesn’t appear to be differences in sprint distances (7). Forwards show superior sprint speed to other positions, with defenders and midfielders showing similar sprint capabilities, followed by goalkeepers (9).

Sprinting bouts are often preceded by players already being in motion (16) and successful acceleration in team sports has been characterised by faster ground contact times and increased stride frequency (17).

Acceleration in soccer can start as an initiation movement in a variety of ways such as shuffling back, moving side on or in stationary facing backwards. This means that acceleration training must go beyond wall drills. Especially when notational analysis shows that defenders may spend much of their time sprinting with their torso and head facing play whilst their legs are forwards, sprinting back towards goal.

It’s also not uncommon for soccer players to sprint in curved lines. Attackers (centre forwards) perform larger angled curved sprints (10-15°+), to run around and in behind defenders who perform smaller angled sprints (7).

Conclusion

The main aims of this Blog Post were threefold 1) discuss how we can identify and program field skills 2) clearly identify and understand the field skills and 3) describe what they look like in soccer, rather than as a general technical model.

To conclude, S&C coaches should ensure they truly understand not only the demands of sports such as soccer and the individual positions, but how movements occur. S&C coaches must reverse engineer their programming process and work backwards from the end outcome to ensure their programming and coaching are context-driven to improve field skills and drive high on-field performance.

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Andrew Hyde

Andrew has a degree in Sport & Exercise Science and a Master’s in Strength and Conditioning from Leeds Beckett University. He is the Director of Aesthetic Athletes where he works with elite soccer players and the general population. Andrew has also worked as a Strength & Conditioning Coach in the NHS, rehabilitating ACL ruptures, and is the Content Manager at Science for Sport, having previously worked as an Intern Strength and Conditioning Coach with Leeds United F.C. Ladies Academy.

More content by Andrew

References

The post Developing Field Skills in Football (Soccer) Players appeared first on Science for Sport.

Recommendations backed by science

By Nathan Kiely
Last updated: February 29th, 2024
17 min read

Contents of Blog Post

1. Introduction
2. Biomechanics of Sprinting
3. Factors Affecting Sprint Performance
4. Sprint Training in Practice
5. Acceleration
6. Maximum Velocity
7. Example Program
8. Conclusion
9. References
10. About the Author
11. Comments

Introduction

Linear sprint speed is commonly perceived to be one of the key determinants of performance in many sporting endeavours. Faster athletes score more often (15), have a bigger impact in match-determining situations (12) and sign bigger professional contracts (33) than their slower peers. As such, it’s unsurprising that speed is such a desirable physical quality.

Speed refers to the displacement of an object or person over a given elapsed time. In sport, we often refer to speed in the context of maximal velocity sprinting. Another important component of sports speed is acceleration, defined as the rate of change in speed. Both aspects of sprinting speed form the foundational concept of speed for sports. These are very different measures and should not be discussed in the same context without a thorough explanation.

Making athletes faster can be a daunting project for strength & conditioning coaches or physical therapists looking for scientifically proven speed development methods to integrate into a thorough athletic development program or return to performance protocols.

Therefore, the aim of this article is to cut through the confusion and provide evidence-based recommendations to help you make your athletes lightning-fast.

Biomechanics of Sprinting

Sprint speed is a by-product of the relationship between stride length and stride frequency. Stride length is the distance covered during each cycle of running gait. Stride frequency refers to the cadence of the gait cycle. Positive or negative changes to stride length or stride frequency will affect sprinting performance.

Running gait consists of two key phases: stance and swing. The stance phase has three stages 1) touch down – in this stage, ground contact is initiated 2) mid-stance – this stage occurs when the centre of mass is directly above the base of support 3) toe-off stage. For male athletes, research suggests stride frequency (the number of strides taken per second) is a rather stable measure across individuals and performers, whereas better sprinters generally display longer stride length, covering more distance with each step taken in comparison to lower-level sprinters (29).

Interestingly, the opposite has been found for female athletes, with improved performance correlating with increased stride frequency (29). This perhaps indicates athletes with lower force-generating capacities may benefit from an increased rate of turnover. This has large implications for how we coach and train athletes with the aim of improving sprint speed, particularly across sexes. As a general rule, increasing athletes’ speeds requires greater force application to cover more distance with each stride and generally should not encourage them to take more steps over a given distance (34).

To do this, they must generate larger ground reaction forces (GRFs) during the stance phase and particularly the propulsion stage of each stride. Given elite sprinters typically display ground contact times of < 0.1 seconds, this places high demands on the elastic qualities of the force-producing muscles in the lower limbs. Generating a large impulse during the stance phase will demand greater degrees of stiffness and strength. In contrast, for female athletes, exercises that emphasize increased turnover are likely beneficial for improving performance. Therefore, developing improved swing phase mechanics for improved heel recovery efficiency and strength in the hip flexor muscles may prove beneficial for females.

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Factors Affecting Sprint Performance

Sprint physiology is complex, with differing physical qualities more heavily associated with either acceleration or maximum velocity. Having said this, there is strong evidence, especially in field sports, that fast is fast, regardless of the sprint phase. Clark et al. (2019) demonstrated that athletes with greater acceleration qualities tended to also display higher maximum sprint velocities and vice-versa, perhaps dispelling the myth that an athlete is either good at accelerating or at top speed and that these qualities are independent (5).

Furthermore, Gabbett (2012) highlights the importance of all aspects of sprint performance in team and field sport athletes by identifying how more than 20 % of all sprints in professional rugby league matches are over 20 meters in length (14). This suggests that not only is acceleration critical to sports performance, but top speed may also play a crucial role, particularly when the nature of these longer sprints is considered (match-deciding plays, line-breaks, long chases, etc.). Given this knowledge, an appropriate speed program for team sports should aim to develop sprint ability at various phases—both short accelerations and maximum velocity, upright sprints.

One of the key factors associated with high-level sprinting, particularly during acceleration, is the efficiency of force application during the stance phase (24). Horizontal GRF relative to body weight is likely a key to improved speed during the initial strides of a sprint. One method proposed for improving horizontal force production is through horizontally orientated strength training. Exercises such as the barbell hip thrust have been hypothesized to generate greater transfer for sprinting (6) due to the force-vector theory which classifies sports skills on the basis of the direction of force expression relative to the global coordinate frame (13).

However, some coaches and more recent research suggest this may not be the case, particularly in acceleration, whereby the untrained eye may ignore the trunk/shank angles displayed by athletes resulting in vertical force production intra-individually, while global force production is horizontal in nature (18). This is not to say an exercise like the hip thrust cannot contribute to improved sprint performance, merely that transfer of training is a complicated topic and is multi-factorial in nature.

Another heavily researched training method for increasing horizontal force application during sprinting is resisted sprints. Resisted sprints come in several forms; resistance band sprints, sled sprints, prowler pushes and although not resisted, incline sprints All these methods work through the same principle of overloading the horizontal component of force application by artificially slowing the athlete down. These methods allow athletes to maintain acceleration posture for far longer than traditional free sprints and can result in far more training density being directed towards peak power production along with reinforcing horizontal GRF orientation (34).

To improve acceleration performance using resisted sprints most effectively, an athlete’s horizontal velocity should be reduced to ~50% of top speed (7, 8). The loads when applied to a sled to create such a decrement in velocity appear to be far greater than what was traditionally believed to be acceptable by coaches who were concerned about alterations to sprint mechanics when using heavy resistance. However, recent literature has demonstrated these concerns are likely misplaced and that a range of light, moderate and heavy sled pushes may be useful at various stages of a properly periodized speed development program (25).

Weyand et al. (2000) and Nagahara et al. (2018) demonstrated that larger GRFs produced during each step were particularly important to sprinting speed during the maximal velocity phase (33, 26). Athletes wanting to run at higher maximum velocities are therefore required to express more force, in a shorter period. Furthermore, lower body strength has also been shown to correlate with sprint performance. McBride et al. (2009) (r = -0.61, p = 0.01), Trajano, et al. (2014) (r = -0.57, p = 0.04) and Baker et al. (1999) (r = -0.66, p<0.05) have all demonstrated strong correlations between 1-RM back squat strength and sprint performance in elite athletes (21, 32, 2).

This should come as little surprise given the gluteal muscles, quadriceps, hamstrings and calves are the prime movers of the force-producing actions shown in sprinting. The strong relationship between lower-body strength and sprint speed may be attributed to the fact that those athletes demonstrating greater force-producing capabilities are able to produce higher peak GRFs, impulse, and increased rate of force development (30).

Perhaps more important than strength, muscle-tendon unit (MTU) stiffness has been shown to correlate strongly with sprint performance in athletes (9). MTU stiffness describes the efficiency with which energy can be transferred from the force-producing muscles into force-receiving surfaces (i.e. the ground). For example, a stiffer ankle complex will reduce energy leakages between the calves and the foot when striking the ground. MTU stiffness can be assessed through tests such as the incremental drop jump test, where jump height or flight time and ground contact times are used to generate a reactive strength index (RSI).

The reactive strength index helps athletes and coaches better understand the quality of forces and speed of application when assessing vertically orientated interactions with the ground. RSI could be considered a key performance indicator for sprint performance due to its high correlation with sprint speed in both acceleration and at maximum velocity (9) and thus can serve as a useful assessment tool for coaches and athletes.

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Sprint Training in Practice

The greatest improvements in sprint performance following training interventions have been shown to come from combined/mixed method training programs that include sprints, plyometric exercises and weights training with both heavy loads (maximal strength training) and moderate loads at high movement velocities (ballistic training) (10). For the best transfer of training, plyometric exercises should be prescribed with the direction of force application in mind. To best develop horizontal power for sprinting, skips, horizontal jumps and bounds have been proposed as the most effective training tools (10), ultimately, and perhaps most importantly, the most potent sprint training stimulus available is sprinting itself (19).

Sprint training and sprinting, in general, come with some inherent risks. Hamstring strain injury (HSI) is the most common injury found during sprinting actions (28), accounting for up to a quarter of all soft-tissue injuries in sports (27). Thus, mitigating this risk of HSI with appropriate programming and complementary training methods is an essential component of a well-developed speed training program. Rather than avoid sprinting through fear of exposure to injury (11), researchers suggest for positive effects from an injury prevention perspective, team and field sport athletes should perform sprint training on a weekly basis (20).

Oakley et al. (2018) go further and suggest team and field-sport athletes should be exposed to 6-10 bouts of sprinting per week with a total volume of 90-120 metres completed at greater than 95 % of maximal sprint speed (27). Furthermore, Carey et al. (2017) suggest athletes should be required to ‘earn the right’ to sprint by appropriately building sprint volumes in alignment with an ACWR (acute: chronic workload ratio) that remains below 1.4:1 (4). This ensures athletes build the necessary fitness required to tolerate increasing training demands appropriately and reduces the likelihood of injury. However, recently scholars have questioned the legitimacy of the ACWR model’s validity due to statistical artefacts and a lack of conceptual integrity, raising further doubts about the ideal progression of training volumes (17).

A commonly cited risk factor for HSI during sprinting is hamstring muscle fascicle length (3). Recent research indicates that the most effective stimulus for improving hamstring fascicle adaptations is sprint training itself (23) once more supporting the importance of actually exposing athletes to sprinting itself. In addition, to complement a sprint training program, hamstring fascicle length can be improved through heavy, supramaximal eccentric training with many research papers citing the Nordic hamstring curl exercise as a useful tool in achieving this goal (1).

Acceleration

During the acceleration phase of a sprint, the athlete’s trunk and shin should assume a positive lean in relation to the ground. Many coaches suggest the legs should work in more of a ‘piston-like’ action during the early strides of a sprint. This is posited to lead to greater horizontal force production with GRFs orientated more negatively, leading to improved propulsion. In order to optimize this technique, the athlete should rise gradually with each stride, rather than abruptly standing tall as soon as possible.

A common error seen during the acceleration phase of a sprint is cueing or intention to maximize stride frequency—being displayed through many short, choppy steps leading to reduced force application and dampening of the centre of mass displacement. That is, the athlete is failing to protect themselves far enough with each stride to create a positive effect on performance. This appears to come from the false assumption, as mentioned earlier, that stride frequency is the common limiting factor in sprint performance. Therefore, a useful cue for many athletes is to instruct them to take ‘big, long powerful strides’ as they initiate the sprint.

During the acceleration phase, the arms should work through an increased range of motion with visual observation of elite performers demonstrating the use of an accentuated ‘arm-split’ in the first few strides. Additionally, as shown in Figure 1, it’s not uncommon to see high-level sprinters harnessing hip internal rotation torques during block starts and therefore this should not be coached out of athletes through the misguided idea that arm and leg action should remain exclusively linear in nature.

Maximum Velocity

Posture
Most coaches agree that during the maximum velocity phase of a sprint, the athlete should assume a tall, upright posture with at most a small or gradual positive lean in the direction being travelled. Additionally, Hansen (2014) suggests that for optimal sprinting technique, the athlete should emphasize hip displacement from the ground, or increase ‘hip height’. (16) In effect, this enables athletes to better access the full extent of their hip extension capacity during the stance phase and translates to improved force application during the sprinting action.

Alignment
Based on visual observation of elite performers, it’s suggested that the limbs should avoid traversing the midline of the body to create excessive rotational force. Furthermore, athletes should also retain a rhythmical arm and leg action and avoid a mechanical or robotic technique that works exclusively in the sagittal plane. The arms and legs ought to trace a curvilinear path with the hands closer to the mid-line at the front and wider at the back during all phases of the sprint and the legs mostly linear through the sagittal plane during upright maximum velocity sprinting.

Range of motion
Hansen (2014) suggests during sprinting, athletes should emphasise ‘front-side dominant’ mechanics, particularly in the lower body (16). This means that the cyclical leg action works predominantly in front of the athlete’s centre of mass (COM). This can be developed through a high knee drive action and rapid heel recovery whereby the trailing leg avoids kicking up high and too far behind the COM. These positions can be seen in Figure 2 at toe-off (knee drive), maximal vertical projection and strike (heel recovery).

Furthermore, the arm action during upright sprinting should be relaxed yet powerful. The elbows will typically be observed in an acutely flexed position at the front side, with the hand close to the mouth or cheek, and then in an obtuse position at the backside with the hand clearing the hip behind the body. A common misnomer is that the elbows should remain in a rigidly fixed right angle during sprinting.

Foot strike
A critical aspect of sprinting technique appears to be the minimization of horizontal braking forces (26). These forces are typically generated during an ‘over-striding’ or ‘heel-striking’ pattern and cause the athlete to decelerate before propulsive forces can be applied during the stance phase, thus creating a net reduction in horizontal velocity. Therefore, foot strike should be initiated as close to directly under the athlete’s COM as possible – without compromising other elements of technical efficiency.

Athletes should be instructed to aim to initiate their ground contact through the ball of the foot, with a dorsiflexed ankle beneath their hips to improve horizontal force orientation and to better prepare the ankle complex to harness its stretch-shortening cycle qualities. A constraints-based drill that may help an athlete with this are mini-hurdle wicket sprints, as seen in the video clip above. When the hurdles are spaced appropriately, stride length can be guided, and foot strike can be orientated more efficiently as the athlete self-organizes their limbs during the exercise. A suggested starting point for mini hurdle spacing is for each hurdle to be spaced at the athletes standing height apart.

Once the athlete completes a few repetitions of the drill, the coach can reassess the spacings through trial and error to modify spacings on an individual basis. As mentioned in the range of motion section above, in order to optimize knee drive, a stiff and powerful foot strike during ground contact is essential. Athletes should be reminded to apply large and abrupt GRFs with each step with cues ranging from ‘hammer the ground’ to audible feedback such as ‘make the ground pop’.

Example Program

Example speed program for field or team sport athletes during an in-season phase, playing one game per week on Saturday.

Tuesday: Acceleration
Warm-up: Walking lunge, hamstring ground sweeps, lateral lunges and side-to-side sumo squats
Technical drills: A-march, A-skip, B-skip, A-run, straight leg bounding
Constraints-based exercise: Hill or sled sprints
Sprinting: 8 x 30 m sprints starting chest to ground with 90 seconds rest between reps
Thursday: Maximum velocity
Warm-up: Walking lunge, hamstring ground sweeps, lateral lunges, side-to-side sumo squats
Technical drills: A-march, A-skip, B-skip, A-run, straight leg bounding
Constraints-based exercise: Mini hurdle wicket sprints
Sprinting: 4 x 60 m walk-in start sprints with 3 mins rest between reps

Conclusion

Making athletes lightning-fast can seem daunting at first. However, as this article has outlined, there are simple components of training, that if programmed with appropriate intensity and volume, and completed consistently, serve as the underlying ingredients in a speed training program that can make athletes lightning fast. Understanding the basic biomechanical principles of speed along with visual examples of how these can be developed in practice is a great place for young coaches and therapists to get started. The pillars of any good speed development program are sound technique, a well-rounded training program consisting of appropriate strength, power and plyometric exercises and emphasis on the act of sprinting itself. With this article, it is my hope you now have fewer doubts about the key aspects of sprint training and can begin to make meaningful differences to your athlete’s health and performance on the field.

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Nathan Kiely

Nathan Kiely is an ASCA recognized strength and conditioning coach, ESSA-accredited sports scientist and holds a BSc (Hons) in Sport & Exercise Science from the University of Technology Sydney. Coach Nathan has a passion for developing speed, power, strength and endurance in the wide array of athletes he’s worked with since 2016 when his coaching career started.

More content by Nathan

References

The post How to Make Your Athletes Lightning Fast appeared first on Science for Sport.

1. Summary
2. What is the force-velocity curve?
3. How do you use the force-velocity curve?
4. What are the force-velocity training zones?
5. Conclusion
6. References
7. About the Author

Summary

The force-velocity curve is a physical representation of the inverse relationship between force and velocity. Understanding the interaction between force and velocity and their influences on exercise selection is vital for any strength and conditioning coach. For example, it is essential that a strength and conditioning coach understands the physiological and biomechanical differences between prescribing a one-repetition maximum (1RM) deadlift and five-repetition maximum (5RM) jump squats – as one will produce higher forces and lower velocities than the other. Failure to understand the relationship and its importance will likely lead to less than optimal training prescription.

What is the force-velocity curve?

Though the force-velocity curve may appear confusing and complicated, it is actually very straightforward. The force-velocity curve is simply a relationship between force and velocity and can, therefore, be displayed on an x-y graph (Figure 1). The x-axis (i.e. horizontal axis) indicates velocity – for example, this may represent muscle contraction velocity, or velocity of movement (measured in meters per second). Whilst the y-axis (i.e. vertical axis) indicates force, for example, this may represent muscle contractile force or the amount of ground reaction force produced (measured in Newtons).

The curve itself shows an inverse relationship between force and velocity, meaning that an increase in force would cause a decrease in velocity, and vice versa. Giving an example, a 1RM back squat would produce high levels of force but would be lifted at a slow velocity. While a counter-movement jump (CMJ) would produce a high movement velocity, it would also only produce low levels of force. This indicates there is a trade-off between force and velocity. That being said, when an exercise produces high levels of force, it will also produce a slow movement velocity and vice versa.

This trade-off between force and velocity is thought to occur due to a decrease in the time available for cross-bridges to be formed – more time equals more cross-bridge formation, and more cross-bridges mean a greater contractile force (1). Therefore, slower velocity exercises allow the athlete to form more cross bridges and develop more force. Higher velocity exercises provide less time for cross bridges to form and therefore result in lower force production.

As a result, different exercises and intensities have been categorised into various segments on the force-velocity curve (Figure 1). In addition, Table 1 demonstrates the force and velocity differences between numerous exercises. Here try and note the force and velocity differences between the same exercises at various intensities.

How do you use the force-velocity curve?

As power is a key determinant in the performances of many sports, optimising an athlete’s power production is of great importance (7, 8, 9, 10, 11, 12). Because power is the product of force multiplied by velocity (Power = Force * Velocity), improving either of these components can lead to increased power production and therefore the explosiveness of the athlete. In most circumstances, the primary objective of strength and power training is to shift the force-velocity curve to the right (Figure 2), resulting in the athlete being able to move larger loads at higher velocities and therefore becoming more explosive.

Shifting the force-velocity curve to the right represents an improved rate of force development (RFD). The RFD simply reflects how fast an athlete can develop force. An athlete with greater RFD capabilities will be more explosive as they can develop larger forces in a shorter period of time.

By only training on one part of the force-velocity curve (e.g. maximum strength), it is likely that the athlete will only improve their performance at that section on the paradigm (Figure 3). For example, only training maximal strength may lead to improvements in force production, but it may also result in a reduction in muscle contractile velocity. As training programmes that combine strength and power training have been repeatedly shown to improve athletic performance more than strength or speed training alone (13), there is no surprise that most strength and conditioning coaches commonly use an all-rounded approach within their programming.

Although most athletes should typically train at each section along the force-velocity curve, the time spent at each zone is dependent on many factors. Some primary considerations include:

• Training age
• The individual’s strengths and weaknesses
• Training objectives
• The sport and position of the athlete
• Time of year/season/stage of the macrocycle

Therefore all parts of the force-velocity curve should typically be trained in order to maximise the explosiveness of the athlete. With that being said, there is often great debate about training multiple components of the force-velocity curve during one microcycle, or whether it is more effective to segregate it into separate blocks. Though this is an important topic, it is inherently tied to training periodisation and is too broad for the scope of this article.

What are the force-velocity training zones?

These zones are classified by the percentage of maximal strength or velocity an athlete can produce. For instance, if an athlete’s maximal force production during a Back Squat 1RM is 3000 Newtons (N), then this would typically represent 100% of their maximal strength capacity, and therefore appear at the apex of the concentric-only force curve (Figure 4). The force percentage then works its way down the curve until it reaches the maximal velocity where little force is produced. Likewise, the maximal velocity represents ≥ 100 % of the athlete’s maximal velocity of movement and appears at the apex of the velocity curve (Figure 4).

Maximal Strength

Maximal strength is simply the maximum amount of force someone is able to produce through a specific movement. For example, a 1RM back squat would represent the maximum amount of force an athlete can produce during that particular exercise. Therefore, this training zone is typically classified by using intensities of approximately > 90 % of 1RM.

Exercise examples include: Back squat, deadlift, and bench press at 90-100 % of 1RM, or any other exercise using this range of intensity.

Strength-Speed

This is a classification for exercises that are not deemed to deliver peak power output, nor peak force, so it sits in a so-called ‘middle-ground’ between maximal strength and peak power. As relatively high intensities are used within this zone (80-90 % of 1RM), it leans more towards strength rather than speed – hence the ‘strength’-speed. The strength-speed zone requires an athlete to produce optimal force in a shorter time frame than the maximal strength zone, and as discussed earlier, this reduces the amount of force that can be produced. Therefore, whilst the strength-speed zone may produce lower peak forces than the maximal strength zone, it is able to achieve higher movement velocities.

Example exercises include: Olympic lifts (i.e. Snatch, Clean & Jerk, Snatch Press at 80-100 % of 1RM).

Peak Power

This is a classification zone for exercises deemed to deliver peak power output. These exercises typically produce the greatest amount of force in the least amount of time. Essentially, power sits in the middle of strength-speed and speed-strength producing the optimal amount of force in the shortest time frame possible (30-80 % of 1RM).

Example exercises include: Second pull variations of the Clean and Snatch, Jump Squats, and Bench Press Throw at 30-80 % of 1RM.

Speed-Strength

Similar to strength-speed, this zone does not deliver peak power, nor peak velocity, so it sits in a ‘middle-ground’ between maximal velocity and peak power. Peak force would be expected to be even lower here compared to strength-speed due to the greater restriction on time available; however, movement velocities will be higher. As relatively high velocities are used within this zone (30-60 % of 1RM), it leans more towards speed rather than strength – hence the ‘speed’-strength.

Example exercises include: Slow stretch-shortening plyometric drills such as: counter movement jumps, and single-leg high hurdle jumps. Light-loaded Jump Squats (30-60 % of 1RM).

Maximal Velocity

Maximal velocity is simply the maximum movement velocity or muscle contractile velocity an athlete is able to produce through a specific movement. For example, a 100m sprint may represent the maximum movement velocity an athlete can produce during that particular exercise. Whereas, assisted sprinting, otherwise known as ‘supramaximal sprinting’ can produce ≥ 100 % movement velocities. Therefore, this training zone is typically classified by using intensities of approximately < 30 % of 1RM.

Exercise examples include: Fast stretch-shortening plyometric drills such as: hopping, bounding, sprinting and assisted sprinting.

These different training zones are merely guidelines for various intensities and can be manipulated to fit the athlete in hand. They have been developed by exercise professionals for educational purposes in order to demonstrate the effects of different exercises and intensities on athletic performance.  However, each training zone, or section of the force-velocity curve, will provide different physiological adaptations and therefore may have its own benefit for the athlete. For example, if an athlete is very strong (i.e. has a high 1RM), but performs poorly during speed tests (e.g. 20m sprint test), then spending time at the maximal velocity and speed-strength zones may be of great benefit for the athlete.

Conclusion

The force-velocity curve demonstrates a simple inverse relationship between force and velocity – meaning an increase in one results in a concurrent decrease in the other. This has strong implications for planning a training programme and should be thoroughly considered when doing so. If an athlete lacks strength but is extremely fast, then perhaps more time should be spent training at higher force intensities to improve their strength capacity. The objective in most athletic training programmes is to improve the athlete’s rate of force development (i.e. their explosiveness), resulting in a rightward shift in the force-velocity curve. Understanding the force-velocity curve is paramount to working as a strength and conditioning specialist, and explicit understanding is essential to becoming a great coach.

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