Breaking Down Agility – Rugby Muscle

It is not the strongest or the most intelligent who will survive but those who can best manage change.

–Charles Darwin

There aren’t many sport which solely need straight line movement. By deduction, that means almost all sports require changes in direction.

Most team sports, such as rugby, football, and basketball, are marked by rapid acceleration, deceleration, and changes of direction (COD) within a 9 m framework (Taskin, 2008). On top of this when we look at court sports (badminton, squash, volleyball) multi-directional first-step quickness and changes in direction occur in a, potentially, even tighter area (about 4 m to 10 m) (Salonikidis, K., & Zafeiridis, A. (2008)) . The reality of this is that the team or athlete who is able to change direction the quickest and with the most efficiency is going to be the one to survive to the next round compared to those who merely have strong linear speed. It is by these standards that we generally judge the ability of a athlete outside of his or her sports specific skill set.

Looking back to the research done by Young, Jones and Montgomery in 2002 we can break the most important components that factor into this ability to change direction in a competition environment (which they called agility) down to 2 main areas. The first is the actual physical ability to change direction quickly. The second is the athletes ability to make the right decision given the perceptual input (visual, auditory, memories, recognition etc). The below shows a graphic representation of their finding and of the sub-components therein.

Figure 1: Adapted from W.B. Young, R James, and I. Montgomerey, 2002, “Is muscle power related to running speed with changes of direction?” Journal of Sports Medicine and Physical Fitness 42(3): 282-288

Whilst the practice and ability of an athletes sports skill will always be the biggest factor in their sporting success it is already obvious that the change in direction component of agility, and it’s subsequent physical demands, play a large enough role that it must be separately and sensibility trained for an athlete or team to reach , or even approach, their true potential.

With the assumption that, for optimum sporting performance, the physical and mental components of agility must be trained being understood it would pay to go over how this might be achieved (without, hopefully, going into excessive detail). Before doing this however it should be noted that ,major surgery notwithstanding, anthropometric variables are fairly set in adult athletes.

Using Figure 1 as a reference:

Change of direction speed (or the physical factors therein)

Leg Muscle Qualities: Most likely the easiest understood factor affecting change of direction speed. In the research of Young, Jones and Montgomery being referenced the qualities of leg muscles are broker down into only 3 areas (Strength, Power and Reactive Strength). This is merely the scope of their research not the be all and end all in muscular qualities related to COD and as such will be expanded upon below.

Strength: Described as “the ability of a given muscle or group of muscles to generate muscular force under specific conditions”(3) As a muscular quality strength can be further refined into a number of more specific “expressions of strength” dependant upon the specific conditions but for the purposes of this only:
- Limit-strength: Characterized by the three components:
  - Limit Concentric Strength – The most force your muscles can voluntarily generate in contraction. For example starting a bench press from the bottom position. Unless noted otherwise when limit strength is written it will be in reference to limit concentric strength.
  - Limit Eccentric Strength – The most force your muscles can voluntarily generate in extension. Think of lowering the bench press downwards. This is important as it is A) a way to load up the stretch shortening cycle (see reactive strength below) in preparation for the concentric phase and B) allows you to handle loads that are greater than your concentric strength.
  - Limit Isometric Strength – The most force your muscles can voluntarily generate in a static position. For this think of pushing your bench press against a static object as hard as you can (approximately 6 seconds). Useful again as it allows a greater force to be produced that a lift limited by limit concentric strength.
- Strength-Speed: is strength in the condition of speed (Ajan, 1988) The body’s ability to move a maximum or near-maximum load quickly.
  - Strength-Speed is moving a heavy(er) weight as fast as you can. Typically, this is around 60% of a 1RM, and the bar moves at a specific velocity of 0.8-1.0m/s.(JANDAČKA, D. AND BEREMLIJSKI, P. 2011)
- Speed-Strength: means speed in conditions of strength (Ajan, 1988)and is characterized by the three components:
  - Starting Strength –The ability to recruit as many motor units as possible instantaneously at the start of a movement (think of the start in a sprint).
  - Explosive Strength –This refers to the acceleration or rate of force development. In other words, once you’ve recruited your maximum number of motor units, how long can you keep them switched on for? A common example often given is that starting strength is the flash on a camera and explosive strength is a flash that can stay on at the same brightness for time.
  - Reactive Strength –This relies on the short term storage of kinetic potential energy within the muscles during the eccentric part of a movement, which can then be transferred to actual kinetic energy during the concentric phase of the movement (think of stretching a rubber band before letting it go). Most of the time this can be thought of as plyometric and quasi-plyometric training.
  - speed-strength also means that you are trying to move as fast as you can, but your are moving a light(er) weight. Typically, this is around 25-40% of a 1RM, and the bar moves at 1.1-1.5m/s.⁽^{Jidovtseff, B., Quièvre, J., Hanon, C. and Crielaard, J. (2009).)}

Anthropometric Variables: In the words of Dorland’s Medical Dictionary “Anthropometry is the science which deals with the measurement of size weight and proportions of the human body”. In other words what shape of a human being you are.

Although as previously noted whilst the way an athlete is structured can and does play a role in how an athlete moves and their potential. Further than changing the athletes lean body mass there isn’t a lot that can be done outside of surgery.

That leaves just one area to influence in terms of anthropometry, lean body mass. Looking at the difference in percentage of lean body mass in sprinters and non-sprinters it becomes clear that the top sprinters have a much lower body fat percentage for their weight that generally population (Vucetic et al. 2005).

Straight Sprinting Speed: Your linear sprint speed and acceleration may in fact be the biggest decider in your ability to change direction. These two qualities share many contributing factors.

Whilst this isn’t the place to discuss linear speed the “equation” (Strength/Bodyweight)+Flexibility+Technique = Speed is an approximation of how linear speed and improvement in linear speed are created. This ties in nicely with our only variable anthropometric measurement of lean body mass. An increase in lean body mass, whilst retaining a similar actual bodyweight, should give and increase in strength. Thus an increase in linear speed. Likewise, a decrease in bodyweight whilst maintaining the same strength will increase linear speed.

The technical side of running as well isn’t really worth our time talking about either. The time spent on it can be better utilised increasing power and strength. The chances that playing rugby you can get enough space and time to get into perfect running technique is slim and the chance that you’ll be moving in a straight line doing so even slimmer.

This harks back to the fact that most work in rugby is done within 9m box. Rather than a straight line.

So, for now we’ll leave it there. And move onto the more complicated stuff next time.

Final Note / Plug

If you’re after a workout that really improve your agility, you’ll need to be doing it on top of that strength work! This is why we’re adding in “Rugby Muscle Agility” as a bonus on the Rugby Muscle System!

So not only will you get the weekly programme delivered to your inbox, you’ll have access to Rugby Muscle Agility that you can use to get you avoiding tackles and stepping like never before!

You can only get this workout though if you’re part of the Rugby Muscle System <- Click the link if you’re interested.

References

Aján, T. and Baroga, L. (1988). Weightlifting fitness for all sports. Budapest: Medicina.

Jandačka, D. and Beremlijski, P. (2011). Determination of Strength Exercise Intensities Based on the Load-Power-Velocity Relationship. Journal of Human Kinetics, 28(-1).

Jidovtseff, B., Quièvre, J., Hanon, C. and Crielaard, J. (2009). Les profils musculaires inertiels permettent une définition plus précise des charges d’entraînement. Science & Sports, 24(2), pp.91-96.

Salonikidis, K. and Zafeiridis, A. (2008). The Effects of Plyometric, Tennis-Drills, and Combined Training on Reaction, Lateral and Linear Speed, Power, and Strength in Novice Tennis Players.Journal of Strength and Conditioning Research, 22(1), pp.182-191.

TaŞkin, H. (2008). Evaluating Sprinting Ability, Density of Acceleration, and Speed Dribbling Ability of Professional Soccer Players With Respect to Their Positions. Journal of Strength and Conditioning Research, 22(5), pp.1481-1486.

Verkhoshansky, Y. and Siff, M. (2009). Supertraining. Rome, Italy: Verkhoshansky, p.1.

Vlatko Vučetić, Vesna Babić, Davor Šentija , Boris Nekić (2005). Anthropometric ad Morphological Characteristics of Runners. Scientific Conference on Kinesiology