9 minute read
Strength for Sprinting
Henk Kraaijenhof
In 2013, Athletics Australia hosted a sprinting conference with the internationally respected Dutch coach, Henk Kraaijenhof. One of the key messages taken from his presentation was the challenge of transfering strength gained from the gym into improved performance on the track. Those back squats might be making your athlete a better lifter and it’s certainly making them look stronger, but is this extra muscle actually transferring to improved 100m times? What can the coach do to ensure that the time the athlete is spending in the weights room is being used most effectively for performance gains?
Strength is specific in a number of different ways and this should determine how and what we train. To maximise the transfer between ‘weight room strength’ and the specific strength required for sprinting, coaches need to ensure that their chosen exercises best replicate the unique conditions of sprinting.
This article will examine how the velocity, muscle group, muscle action, direction of force and joint angle of the muscles trained will effect the training outcomes and how these factors can be manipulated to maximise training outcomes for sprinting performance.
Strength is Specific
The ‘Specific Adaptation to Imposed Demand’ or ‘Specificity’ principle suggests that strength gains are greatest when tested using the same characteristics as the training program.
Velocity
The Principle
Training exercises that are performed at a high velocity will lead to proportionally greater gains in high velocity strength. For example, exercises that are performed at high speed such as hang snatches (click here for an example video) will theoretically lead to a proportionally greater improvement in an athletes ability to perform high velocity exercises than exercises performed at low velocity (Ayers et al., 2016).
The Evidence
Coyle et al. (1981) provided the foundation of practical evidence to support the relationship between velocity of training and specific strength outcomes. The study tested athletes who trained using knee extensions for six weeks using either a slow (60 0 /s) or a fast (300 0 /s) technique. The results showed that participants from the slow treatment group had proportionally greater strength gains at low velocity and those from the fast treatment group had proprotionally greater high velocity strength gains.
Interestingly, the slow treatment group did not show any improvement of high velocity strength, whereas training at faster speeds did also result in an improvement of low velocity strength, although signficantly less than the slow treatment group.
The velocity-specific nature of strength has since been supported by a of studies that have demonstrated it is true for single-joint exercises (Moss et al., 1997; Ingebrigtsen et al., 2009), multi-joint exercises (Mora-Custodio et al., 2016) and in trained (Aagaard et al., 1994) and untrained athletes (Moss et al., 1997).
The Sprinting Implication
Sprinting is primarily a high velocity action, so strength training at high speeds should result in greater improvement of sprinting performance than training at lower speeds.
A longitudinal study by Loturco et al. (2015) supported this hypothesis, demonstrating that a high velocity strength program resulted in proportionally a greater improvement in 5, 10 and 20 metre sprint times compared with a lower velocity training program.
The Coaching Application
The velocity that an execise is performed can be manipulated using the following methods:
• Reducing the weight of the training implement. There is some evidence to suggest that exercises conducted between 30 and 60 percent of the athlete’s 1RM are the most effective for improving high velocity strength and improving sprinting performance (Young, 2006; Thomas et al., 2007; Mora-Custodio et al., 2016).
• Intent to produce force quickly. There is some evidence to suggest that the actual speed of the action is less important than the cognitive intention of the athlete. That is to say, there will be improvement in high velocity strength when the athlete intends to perform training at maximal velocity, regardless of the actual movement speed (Behm & Sale, 1993). See Balshaw et al. (2016) for an excellent explanation of the proposed neural factors involved in this.
Young (2006) also advises that sprinters will also still benefit from a general non-specific resistance program and that a sprinter’s program should include more than exclusively high-velocity exercises. General resistance training is likely to aid injury prevention and facilitate the development of high velocity strength.
Muscle Group
The Principle
It is well understood that strength gains are specific to the groups of muscle that are being stressed. Athletes must incorporate a range different exercises to develop the range of muscles that contribute to sprinting performance (Gonyea et al., 1986; Rogers & Evans, 1993).
The Sprinting Implication
Understanding the most important muscles for sprinting performance will assist athletes and coaches to prioritise training of the muscle groups that are most important for sprinting success.
The Evidence
The current evidence suggests that the hip extensors, hip flexors and knee flexors are the most important specific strength requirement for sprinters. A comparison between the strength of elite sprinters and the general public demonstrated that sprinters tended to have overall greater muscle mass than the average individual, but had proportionally even greater strength in their hip extensors, flexors and knee flexors (Handsfield et al., 2016).
Hip Extensors (esp. Semitendinosus, Gluteus maximus) Mann & Hagy (1980) demonstrated that sprinting ability improved with greater hip extensor strength and this has since been supported by further studies that have examined the relationship between the two (Belli, Kyrolainen & Komi, 2002; Young, 2006; Beardsley & Contreras, 2014).
Electromyographic analysis of the sprinting action has suggested that the hamstrings may have the greatest increase in muscle activation as running speed increases, suggesting that they may be an important driver of running velocity (Kyrolainen et al., 2005).
Hip Flexors (esp. Psoas major, Rectus femoris) The size of an athlete’s psoas major has been shown to be correlated to their sprinting ability (Copaver, Hertogh & Hue, 2013) and has been shown to be an important muscle for increase stride frequency during sprinting (Dorn et al., 2012). Evidence has shown that a hip flexion program can improve 10-yard and 40-yard sprinting times (Deane et al., 2005).
The Coaching Application
As strength is specific, exercises that develop the strength ofthe hip extensors and flexors should be prioritised.
The following exercises have been recommended by strengthand conditioning experts for sprinters looking to buildstrength in these muscle groups.
The following table provides a list of strength exercisesthat may be appropriate for sprinters, the strength andconditioning expert advocating their use, and a videodemonstration of how they may be performed.
Exercise
Kettlebell Swing
Nordic Hamstring Curl
Resisted Hip Flexion
Hip Thrusts
Barbell Glute Bridge
Single Leg Romanian Deadlift
Trap Bar Deadlift Jump
Lying Leg Curl
What about the Quadriceps?
A recent study by Miyake et al. (2017) tested the difference in the cross-sectional area of the quadriceps between sprinters and non-sprinters. The results demonstrated that there was not a significant difference in the size of the quadriceps muscles between sprinters and non-sprinters, suggesting that the muscle group is not a signficant contributor to sprinting success. The researchers also found a lack of correlation between the size of an athlete’s quadriceps and their reported personal best time over 100 metres. This finding was supported by Bex et al. (2016) who found that a greater hamstring:quadriceps ratio was correlated with faster sprinting performances.
However, it should be noted that Handsfield et al.’s (2016) study found that the rectus femoris to be one of the proportionally largest muscles in elite sprinters compared with non-sprinters, suggesting that further research is required before we fully understood the importance of this muscle group for sprinters.
Muscle Action
The Principle
Strength is specific to the muscle action that is being trained. Eccentric training produces proportionally greater gains in eccentric strength and concentric training produces proportionally greater gains in concentric strength (Vike et al., 2006).
The Sprinting Implication
Biomechanical analysis of the sprinting action demonstrates that sprinting requires concentric strength in the hip flexors and hip extensors and eccentric strength in the knee flexors (Hunter et al., 2005; Chumanov et al., 2011).
Coaches should consider implementing an eccentric-specific training routine to ensure the athlete develops the required eccentric strength, especially in their hamstrings. While many common strength exercises include both an eccentric and concentric phase, an individuals’ eccentric 1RM is usually significantly greater than their concentric 1RM (Kelly et al., 2015). The implication of this is that exercises with both an eccentric and concentric phase are not developing the athlete’s eccentric strength to the same degree as it develops their concentric strength as the weight or number of repetitions is being limited by their concentric maximum.
The Evidence
de Hoyo et al. (2015) demonstrated that an eccentric-specific training program was an effective intervention for improving maximum running speed in junior football players in addition to assisting injury prevention. This has been supported by further studies that demonstrate that the development of eccentric strength using a plyometrics program has been effective for improving speed and acceleration (Rimmer & Sleivert 2000; Faigenbaum et al., 2007).
The Nordic Hamstring Curl has been found to be a more effective exercise for developing eccentric hamstring strength than traditional hamstring curls (Mjolsnes et al., 2004).
The Coaching Application
While the advantages of including concentric and eccentricspecific exercises for sprinting performance and assisting injury prevention have been well documented, there is little peer-reviewed evidence to support an optimal program for sprinters.
Mjoslnes et al. improved their participant’s eccentric knee flexor strength using the Nordic Hamstring Curl program.
Strength and conditioning expert Chris Brearley recommends implementing two sessions of eccentric-specific exercises per week out of season (alternating between Nordic Hamstring Curls and Flywheel Leg Curls) and one session per week in-season.
Bret Contreras recommends that the Nordic Hamstring Curl be conducted with a resistance band that allows the athlete to control the movement throughout the full range of motion. When the majority of athletes attempt the motion you will notice that they lose control of the descent during the second half of the motion, whereas the resistance band will provide greater support as the athlete lowers themselves closer to the ground, ensuring that their muscles are active throughout the exercise.
Direction of Force
The Principle
Strength gains are specific to the direction of force generated in training. Exercises that generate force in a horizontal (anteroposterior) direction lead to proportionally greater gains in the abiliy to generate force in a horiztonal direction.
The Sprinting Implication
Morin et al. (2012) and Kawamori et al. (2013) demonstrated that the ability to generate horizontal force is a key determinant of sprinting ability. While sprinting does require both horizontal and vertical generation of force (Weyand, 2010), the priority for the sprinter is likely to be training exercises which develop their ability to generate horizontal force. This is supported by Rabita et al. (2015) who found that the athlete’s ability to generate horizontal force was signficantly correlated with their sprinting performance.
The Evidence
The best evidence for the effectiveness of exercises generating a horizontal force vector for improving sprinting performance was a comparative study between the hip thrust and front squat by Contreras et al. (2017). The study found a significantly greater improvement in the hip thrust intervention group, supporting the theoretical evidence that horizontal force generation is the most important for sprinting performance.
The Coaching Application
Contreras et al. used a progression of hip thrusts to improve sprinting performance. There is also evidence to suggest that the inclusion of horizontal plyometrics can be effective for improving an athlete’s speed (Ozbar, Ates & Agopyan, 2004).
Conclusion
By understanding the ways that strength is specific, we areable to design a strength program that results in a maximal improvement in performance. However, while this article explored some of the ways that strength is specific, it is by no means intended to be an exhaustive list of the way strength transfers to the unique requirements of sprinting. The challenge for you to take from this article is to think about the other unique strength requirements of sprinting and which exercises in the gym will transfer most effectively.
Note on Coaching Young Athletes
“Even though laboratory research demonstrates thatspecificity training results in faster adaptation and leads tofaster increments in performance, this does not mean thatcoaches and athletes have to incorporate specificity trainingfrom an early age. In this narrow approach to children’ssport, the only scope of training is achieving quick resultsirrespective of what may happen in the future of the youngathlete...This is like trying to build a high-rise building on apoor foundation.”
