Rate of force development: What golfers need to know

This is a guest post by Alex Ehlert, Alex has really caught my attention of late with his commitment to seeking out best practice for golf fitness by applying research backed evidence (something I like to think of as a defining quality in our training at Stronger Golf too).

One common complaint I have heard about golf resistance training is looking at something called the rate of force development or RFD, basically this is the amount of time it takes to develop force.

I’ve heard it said that strength is unimportant in golf because maximal force does not have time to develop during the short time-frame of a golf swing, or that the relative light weight of the club makes it irrelevant.

The first part is true to some extent, studies have shown that it takes about 300 milliseconds or more to create maximal isometric force and most athletic actions, including golf swings  occur in a shorter time frame than that (6). But if strength were not important for this reason, it would also be equally useless in nearly every explosive movement in the athletic world, which is obviously not the case. The modern golf swing takes no shorter time than most explosive athletic actions, yet resistance training is common practice in nearly every sport but golf. I want to show why resistance training is important for all explosive activities, including golf.

There have been multiple studies showing that resistance training increased RFD, meaning force was able to be produced more rapidly (1). In other words not only does resistance training allow a greater potential for maximum force, it also allows for faster development of that force. Further, one unique study compared the factors that influence RFD at various time points (2). They found that most of the variance between individuals’ RFD in the first 90 milliseconds was correlated with contractile properties. This refers to the contractile proteins within the cell itself and how rapidly they can cause action. The study found after 90 milliseconds, as much as 52-81% of the differences in RFD were attributed to the individual’s maximal contraction force A.K.A. maximal strength. 90 milliseconds is well within the time frame of a golf swing, so it would seem that strength plays a large factor in clubhead speed after all.

Part of the reason for the confusion on strength’s role in golf has to do with people throwing around the term “power” without actually knowing what it is. Power has a very simple formula of Work/Time, with Work being Force x Distance. So you can simplify it even more to Power = Force x Velocity since Velocity=Distance/Time.

power-formula-image

Therefore it seems pretty obvious that a couple factors influence the ability to create power. The first being the ability to generate a lot of force, and the second being the ability to do so with high velocity (5).

It is also important to note that muscle operates under the Force-Velocity relationship. As velocity increases, the ability to generate force decreases. Without getting too physiological, the explanation for this is that with higher velocities, there is less time to allow the contractile proteins to bind together and create cross-bridges which help produce force. This does not mean that a sport requiring high velocity like golf has no use for maximizing force, it just means that optimal power is performed at a level below maximal force as well as maximal velocity. This is not unique to golf, you want the right blend of velocity and force to create as much power as possible in any explosive action.

So how do we develop optimal power and rate of force development?

When trying to increase power, it is important to focus on several factors: overall muscle strength, the ability to develop forces rapidly (RFD), and the ability to utilize large forces at velocity (5). These factors work together, but it is strength that lays the foundation for the others. Put simply, stronger athletes consistently have more potential for high power output (3). Indeed, research with comparatively weak athletes, performing programs with just strength training, led to significant increases in power without any power-specific training (4).

Editors note: The take home message here is therefore the need to develop your strength base first.

This idea brings up another issue, how strong is strong enough? This topic is one without a clear-cut answer but a few things have been shown. First, one study with soccer players found that those who could squat 2x their body mass were significantly more proficient in power activities like sprinting and squat jumps (7). I have also seen consistently the idea of a broad jump of 1.2-1.4x an athlete’s height to be a good goal. Either way I would venture to guess that a large majority of golfers are not currently capable of these feats, meaning there is probably significant area for improvement in the strength department. Others have developed pretty good standards of strength that correlate well with golf performance that golfers should strive for.

It has been reported that stronger athletes are more responsive to power training than weaker athletes so having sufficient strength can help receive more of a benefit from power-specific exercises (4). It is important to note, however, that this does not mean stronger athletes should perform only power movements or that weaker athletes will not also benefit from plyometrics and other powerful exercises. It means that developing a foundation of strength is important for those who are deficient in that area and even once it is achieved a continued focus on strength will prevent detraining, or the decrease in strength over time.

Editors note: For our attempt at answering the question of how strong is strong enough for golf take a look at our strength standards for golfers post.

Once a foundation of strength has been built, golfers can further enhance power by incorporating plyometrics, ballistics, and other power movements into their program. These exercises will help the athlete develop force rapidly and utilize it at high speeds.

Remember that force velocity curve from earlier? To optimally train the body for athletic performance we need to perform at various areas of the force-velocity curve, meaning working on maximizing strength at the high-force, low-velocity end as well as working on RFD at the lower-force, high-velocity end.

Force-Velocity-Curve

This can be done by using a number of methods, either using certain exercises and altering the loads to train for strength vs power e.g. squatting with lower weight (50% max) some times and performing reps explosively, and squatting at a heavier range at others (80-100% or more), or by utilizing different exercises e.g. squats and deadlifts to develop strength and then incorporating more “power” movements like box jumps and medicine ball throws to incorporate speed and explosiveness.  Both of these methods have been utilized with success as well as a combination of the two as long as the program is very well designed and the individual is screened for movement and strength deficiencies before proceeding.

One last important idea to remember is periodization and the sequencing of a program. This refers to planning how the program is going to progress to fulfill the individual’s goals. This will be different based on the person’s needs from training. For those lacking the foundation of strength (which is many golfers), it often initially includes a time to correct any deficiencies in their movements that might harm their ability to train. Then it will include a time of resistance training to develop that foundation of strength. Then when the foundation of strength is sufficient, the athlete will be prepared for maximal benefit from a mixed methods program that includes explosive power movements. I also believe mobility and stability exercises should be incorporated into each stage of the training. Finally, the program should also be utilizing progressive overload where the individual is given more difficult tasks over time since the body needs to be challenged in order to change in a positive manner.

References

1.     Aagaard, P., Simonsen, E. B., Andersen, J. L., Magnusson, P., & Dyhre-Poulsen, P. (2002). Increased rate of force development and neural drive of human skeletal muscle following resistance training. Journal of applied physiology, 93(4), 1318-1326.

2.     Andersen, L. L., & Aagaard, P. (2006). Influence of maximal muscle strength and intrinsic muscle contractile properties on contractile rate of force development. European journal of applied physiology, 96(1), 46-52.

3.     Baker, D. (2001). Comparison of upper-body strength and power between professional and college-aged rugby league players. The Journal of Strength & Conditioning Research, 15(1), 30-35.

4.     Cormie, P., McGuigan, M. R., & Newton, R. U. (2010). Influence of strength on magnitude and mechanisms of adaptation to power training. Med Sci Sports Exerc, 42(8), 1566-81.

5.     Kawamori, N., & Haff, G. G. (2004). The optimal training load for the development of muscular power. The Journal of Strength & Conditioning Research, 18(3), 675-684.

6.     Thorstensson, A., Karlsson, J., Viitasalo, J. H. T., Luhtanen, P., & Komi, P. V. (1976). Effect of strength training on EMG of human skeletal muscle. Acta Physiologica Scandinavica, 98(2), 232-236.

7.     Wisløff, U., Castagna, C., Helgerud, J., Jones, R., & Hoff, J. (2004). Strong correlation of maximal squat strength with sprint performance and vertical jump height in elite soccer players. British journal of sports medicine, 38(3), 285-288.

Alex is former NCAA Division 1 Golfer who was able to gain 20 yards by becoming stronger and more athletic. He is now a Masters Student in Exercise Physiology and writes about optimising golf fitness using an evidence-based approach at his blog www.golfathlete.blogspot.co.uk and can be contacted via twitter.

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