How strong is strong enough?

Strength is the ability to produce large amounts of force and is readily demonstrated as the ability to pick up heavy things. Commonly accepted wisdom is that the heavier the things that you can pick up, the better for general sports performance. As a result, strength and conditioning coach positions (with a heavy emphasis on the STRENGTH side of the title) have proliferated in all areas of sport to support everyone from the high school hopefuls, to the weekend warriors, to elite professionals. The rapid expansion of the strength and conditioning industry in the past 20 years has certainly ensured that sportsmen and women fill out their T-shirts better than before (just google some images of 80’s athletes if you don’t believe me), but does it do what it’s meant to do? Does strength and conditioning make us better at sport?

Figure 1 – Contrast the physiques of rugby players prior to and post- strength and conditioning era.

The key concept I’d like to examine in this article is that of “transfer” of strength and conditioning to sport-specific performance. To what extent does what we are able to do in the weight room influence what we are able to do on the sports field.

In a recent review of strength training research entitled “The importance of muscular strength for athletic performance” (1), the authors point out that the ability to produce large amounts of force is critical for performance in force-time dependent tasks such as sprinting, jumping and change of direction. Based on this, it seems that increased strength does transfer to sports performance. The ability to lift heavy things should make you better at the sport you play.

BUT, if this is the case, why aren’t the strongest athletes in the world also the fastest? Usain Bolt doesn’t hold the world squat record. Arnold Schwarzenegger was Mr Olympia seven times, but was never invited to compete at the Olympics by either Austria or America. So where does the relationship between strength and performance uncouple?

Suchomel and colleagues have theorised that in the medium term (2 to 3 years strength training) increases in strength are very closely associated with improved sporting performance (Figure 2). They also, however, acknowledge that well trained (very strong) individuals develop a “strength reserve” where further increases in strength are no longer directly beneficial to sporting performance (Figure 2). For all intents and purposes, these individuals are “strong enough” and further increases in physical strength won’t have a notable improvement of sports performance. These individuals then need to look to other methods such as improving technique or efficiency of movement to develop further.

What this means, is that there is a theoretical cut-off point, beyond which further improvements in strength are no longer of performance benefit. Practically, this means asking questions like “Will improving X player’s bench press from 80kg to 90kg make him a better footballer?”. The answers to these questions will be contextual and will depend on factors such as the nature of the sport in question, the age and training history of the athlete and the amount of time available to dedicate to strength training. This type of cost-benefit analysis should underpin everything the strength and conditioning coach does. We should constantly search for the easy wins and the training that delivers the most benefit for time invested.

Based on the information presented in this article, it makes sense that the first stop on the training pathway for most strength and conditioning coaches is to develop strength. It is not hard to make athletes stronger, and for inexperienced athletes, with low training age, these increases in strength relate directly to on-field performance. In fact, this is best practice in the vast majority of situations. But what about when that athlete matures, when he has spent long enough in a program to be considered well-trained? When do we as coaches evolve our program to reflect that the athlete is now “strong enough” and now needs a different stimulus in order to progress?

The answer is presently unclear. (Any young students out there looking for a research project, this is a good one to take on!) Anecdotally, it has been suggested that a squat of 2x body weight is necessary for elite sprint performance. This is likely to be more of a guideline than a rule, as I doubt very much that Usain Bolt and Andre de Grasse regularly (or ever) perform this feat of strength. Research still needs to catch up with practice in this area, and we need to determine the performance effects of shifting an athlete from 1.5x to 2.0x and 2.0 to 2.5x their body mass squat (and other exercises for that matter). From my personal experience, I can confirm that <1.5x body mass squat is definitely not strong enough.

One final consideration in the strength “transfer” conundrum is the aspect of athlete skill. An athlete’s sporting ability is directly related to his ability to effectively apply force in the dynamic, high-velocity environment of competition. Athletes with high skill levels (effective at transferring force) likely have the most to gain from improved strength, and may be able to sustain these gains at higher levels of relative strength. On the other hand, low skill athletes (ineffective at force transfer), may only be able to transfer relatively little strength gains into performance improvement. Time with these athletes may be better spent developing coordination of force transfer, than chasing strength gains.

Ultimately, until research has better defined the relationship between strength and performance, we will rely on “coaches eye” and qualitative assessments to determine the content of our training programs. What is important to acknowledge is that strength training isn’t a “fix all approach” to performance improvement. Strength training may well be the most well-used tool in our tool box, but just because we have a hammer doesn’t mean every athlete is a nail. Use the right tool for the job!

References Suchomel, T., Nimphius, S., and Stone, M.H., 2016. The importance of muscular strength in athletic performance. Sports Med., 46(10):1419-49