Big and strong?

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Sit down and prepare yourself for a little heresy. Just for a moment, can you take what you know, think and believe and leave it in this tray. Don’t worry it’s safe there and you’ll be able to pick it up on your way out. Our topic is size (muscle size) and it’s relationship to strength. Buckner et al (2016) remind us that so far research has shed very little light on the link between getting bigger (muscular hypertrophy) and getting stronger (muscular strength), and it seems unlikely that there is a simple and precise association between the two. Unfortunately, that observation does not appear to have fazed either the strength and conditioning world or academic programmes, with both continuing to assume there is an inextricable link. Indeed in the worlds of strength and conditioning and fitness, we are taught a couple of ‘cast iron’ never-to-be-doubted principles;

• Bigger will mean stronger,
• Stronger will mean superior performance.

So two themes here – hypertrophy’s links with strength, and hypertrophy/strength’s associations with performance. Both of the above principles make such logical sense that we never think to really question them. The principles are ‘kind of’ supported by our theoretical understandings and there is undoubtedly a lot of confirmatory bias. For example, I could draw you a nice theoretical diagram that shows the slope of your force-time curve, and then convince you that if we could just steepen that slope or move it to the left slightly, you would be more explosive on court!

The thing is that when people would like something to be true, they tend to end up convincing themselves that it is true – and that’s confirmatory bias. Every time we observe a highly muscular person demonstrating massive strength or power it confirms our biased thinking – BIG equals STRONG. That same biased thinking stops us from wondering how a slender little Taekwondo guy can launch such explosive kicks, those ballerinas are able to leap so high, or that gymnast can generate so much power from the floor?

Biased thinking stops us questioning

These athletes that I’ve thrown at you are not highly muscular (or in the case of the gymnast, not large and muscular) so we tend to discount any discrepancies between what we see and what we believe, and with our bias we reject those inconsistencies. We very rarely go back to those principles and challenge our thinking and understanding.

The thing is that most strength training studies are not exactly designed to demonstrate that strength training improves actual performance (Buckner et al, 2018 – a great read by the way if you can get your hands on it). Those studies would simply be too difficult to design and control. So we are asked to trust the experts whose compelling logic explains why bigger muscles will help athletes. That’s no doubt why there are relatively few studies that can demonstrate even modest performance improvements with strength training. The absence of studies demonstrating that strength training improves sporting performance has always surprised me – I’d assumed that was well proven and established.

Performance in many sports is difficult to measure and the ways that we are able to test strength generally provide poor proxy measures of performance. So we are asked to take a leap of faith to believe that an improvement in a 1RM squat will, in turn, enhance an athlete’s ability to rebound for four full quarters of basketball. Most strength/performance research involves cross-sectional designs and these will show that successful performers in a particular sport are typically bigger and stronger than non-elites.

few studies demonstrate that resistance training improves skilled sports performance

What these studies lack is a control group that might have just practiced their sport (or done other things) instead of hitting the weights (Buckner et al, 2018). All that the research studies can really tell us is what they were designed to tell us. They don’t tell us whether strength actually distinguishes an elite from a novice performer. They don’t tell us whether an elite athlete getting ‘gym stronger’ is going to translate into them performing better on the court or field. Clearly what we need are studies that demonstrate that a change in strength (or the rate of force development) improves the performance of an actual skill (not just their 1RM or single vertical jump), and that strength gain is superior to simply practicing those sport-specific skills. I’m going to say that in practice, we are much too afraid to take that risk and risk falling behind others – but is it really a risk?

Buckner et al (2018) suggest that individual potential for skeletal muscle growth is unlikely to be infinite, and they argue that most adult athletes will not increase their muscle mass much beyond their first year of weight training. I’m sure you can throw examples of exceptions at me, and I acknowledge that some people do continue to get bigger – but how many of those also have parallel improvements in skill or sport-speed? Unless your sport is some form of weight lifting, the direct transfer is likely minimal. Most of the ‘key lifts’ that take place in the gym involved vertical expressions of force, but in sport and life, the expressions of force are lateral, horizontal and rotational and involve a skill of force application.

the skill of force application may be more important than absolute strength

In a fascinating unpublished study, Buckner et al (2016) found that trained participants performing a single 1RM lift at each training session had large increases in 1RM strength with no change in muscle size. The contralateral limb, that performed fatiguing sets as well as the 1RM training had significant hypertrophy but had no better strength adaptation than the limb that just performed 1RM per session. So getting stronger and getting bigger was not the same thing – the two don’t appear to be as closely linked as once thought.

There are ‘oodles’ of opinions in the resistance training literature, and thousands more ideas from ‘experts’ on how to best achieve hypertrophy and strength gains. But as Carpinelli (2008) points out, we still don’t really understand the specific mechanisms of fatigue or the optimal stimulus for strength or size gains. As different loading methods can produce diverse adaptations in neural control, structure and function, there is a real need for exercise professionals to step back and carefully consider the desired training outcomes that they are seeking (Fisher et al, 2017). As professionals, we need to rethink the relevance of some of those adaptations to performance and weigh those up against the potential ‘cost’ of resistance training.

Resistance training HAS TO add significant value as it takes up a lot of scarce training time and consumes a lot of ‘training energy’. We know for example that any muscle inflammation secondary to resistance training likely contributes to the risk of low-frequency fatigue – so there is always a cost associated with any form of training. Buckner et al (2018) acknowledge that while resistance training may provide a useful size and strength boost for younger athletes, given the tenuous links with actual sports performance the strongest justification for resistance training might actually be injury prevention. As Young et al (2018) explain increased mass (lean muscle mass in particular) has benefits for certain sports where collisions are dependent on an athlete’s momentum. A larger mass traveling at speed involves more momentum and that increased momentum is more difficult to stop or to push off course. But if speed is not maintained that increased mass could have no real impact on momentum. The downside of more mass is that a heavier body is going to be more difficult to accelerate, to decelerate and to rapidly change direction. For many sports, the real need for strength improvement is likely relative strength rather than absolute strength. Relative strength gains are generally achieved through mainly neural adaptations, rather than through creating more muscle mass (Young et al, 2018).

So….this is all fascinating and inevitably confusing. Buckner et al’s (2018) review demonstrates that growth and strength can and do occur independently of one another, and maybe its time we started thinking about what we are really trying to achieve. Their paper raises questions about our historical beliefs that hypertrophy is a precursor and mechanism for strength. I’m not saying that anyone has the answers or knows any better, but I do believe that as exercise professionals we can ‘think better’ about these things. Conditioning could benefit from a major rethink of resistance training programming for performance enhancement – do we really need to increase muscle mass or should we be focusing more on relative strength?

Class dismissed, don’t forget that stuff you left in the tray!

Best, Phil

Selected references

1. Buckner, S.L. et al (2016) The Problem Of Muscle Hypertrophy: Revisited. Muscle Nerve 54: 1012–1014.
2. Buckner, S.L. et al. (2018) Resistance exercise and sports performance: The minority report. Medical Hypotheses 113;1-5
3. Carpinelli, R.N., (2008) The size principle and a critical analysis of the unsubstantiated Heavier-Is-Better recommendation for resistance training. J Exerc Sci Fit 6(2); 67–86.
4. Fisher, J. et al (2017) High- and Low-Load Resistance Training: Interpretation and Practical Application of Current Research Findings Sports Medicine 47(3): 393–400.
5. Young, W., et al (2018) Development of muscle mass: how much is optimum for performance? Strength and Conditioning Journal Publish Ahead of Print DOI: 10.1519/SSC.0000000000000443