How to test an athlete’s max. strength on a shoestring budget

Using modern technology to make life easier as a coach

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By Owen Walker
16 Apr 2019 | 5 min read

Contents of Article

The problem
What’s the solution
The conclusion
References
About the author
Comments

The problem

If you’re in the business of improving an athlete’s performance, then knowing their maximal strength is very important. An athlete’s maximal strength is the total amount of force they can produce in a given movement (e.g. back squat) and is also commonly referred to as their ‘maximal force capacity’.

While it’s important to understand your athlete’s maximal force capacity unless you have a bulbous budget to work with, simply measuring it can be a difficult task. For example, a force plate will set you back tens of thousands of dollars [1], a dynamic 1-repetition maximum (1RM) test will take a long time to administer, cause fatigue and muscle soreness, and not even give accurate results if the athlete is being tested on a day when they’re fatigued.

You could also try to estimate an athlete’s 1RM using a velocity-based training (VBT) device, however, as the research has shown, this method isn’t very accurate [2]. The only way to get more reliable 1RM estimates using VBT devices is to use loads very close to an athlete’s 1RM [3], but that then defeats the purpose of estimating it in the first place.

What’s the solution?

As technology advances, most things tend to get easier, quicker, and cheaper and there seems to be no exception in the world of sports performance.

With advances in technology and the success of recent research [4], any coach on a shoestring budget can now accurately measure an athlete’s maximum strength quickly and easily using a device known as a ‘crane scale’. A crane scale (Figure 1) is what is known as a ‘load cell’ or ‘dynamometer’ and it’s simply used to measure the weight of something and typically costs less than $100 (USD). These devices are also almost small enough to fit inside your pocket, making them perfect from a portability standpoint.

Figure 1. Crane Scale

Because of the cheap cost and portability of the device, a recent study which was reviewed in issue #25 (November 2018) of our Performance Digest was conducted by Urquhart and colleagues [4] to test whether it could be used to accurately measure an athlete’s 1RM in an isometric movement (i.e. the isometric mid-thigh pull). If you wish to read the full details of the study and our expert review of it, including practical takeaways and expert comments, then click here for all the details.

What the researchers found

The crane scale was shown to have a near perfect relationship with the force plate. Based on the data collected and the statistical breakdown, it appears that a commercial hand scale, particularly the Crane model used, was reliable enough to be used for a crude indicator of isometric strength.

Table 1. below demonstrates the accuracy of the crane scale when weights were hung from it [4].

The authors also measured the accuracy of the crane scale against the force plate when measuring an athlete’s isometric mid-thigh pull (IMTP)* and found that the average difference between the two was only 2.7% – a very small difference indeed.

*If you want to know more about what the IMTP is and why it’s the preferred exercise for measuring maximal strength (i.e. maximal force capacity), then we highly recommend you read this article on the topic.

The conclusion

Based on this information and the excellent work of Urquhart and colleagues, coaches/practitioners around the world who’re working on a shoestring budget can simply measure their athlete’s maximal strength in a quick and easy fashion and feel confident that the results they’ve got are accurate.

This is tremendously helpful for thousands of coaches out there who’re constantly “pushing the envelope” and finding new and exciting ways to provide the best service possible to their athletes. If you’re one of these coaches/practitioners who’re constantly trying to evolve your practice but don’t have a big budget to work with, then the crane scale is going to be a fantastic tool to add to your toolbox.

Not only that, but the crane scale can be used for many different purposes, the most popular of which are:

Measure an athlete’s maximum strength.
Measure the effectiveness of training interventions.
Reduce injury risk.
Monitoring fatigue (understand the athlete’s “freshness/readiness to train”).
Comparing athletes’ and creating competition.
Measuring between-limb asymmetries.

References

Reference List (click here to open)

2019. Force Plates – Do you need one? [ONLINE] Available at: https://kinetic.com.au/pdf/Force_Plates.pdf. [Accessed 15 April 2019]. https://kinetic.com.au/pdf/Force_Plates.pdf

Banyard, HG, Nosaka, K, and Haff, GG. Reliability and validity of the load–velocity relationship to predict the 1RM back squat. J Strength Cond Res 31(7): 1897–1904, 2017. https://www.ncbi.nlm.nih.gov/pubmed/27669192

Jidovtseff, B., Harris, N.K.., Crielaard, J.M., Cronin, J.B. Using the load-velocity relationship for 1RM prediction. Journal of Strength and Conditioning Research. 25: 267-270. 2011. https://www.ncbi.nlm.nih.gov/pubmed/19966589

Michael N. Urquhart, Chris Bishop & Anthony N. Turner. (2018) Validation of a crane scale for the assessment of portable isometric mid-thigh pulls. Journal of Australian Strength & Conditioning. 26(5):28-33. http://eprints.mdx.ac.uk/23039/

About the Author

Owen Walker

Owen Walker MSc CSCS
Founder and Director of Science for Sport

Owen is the founder and director of Science for Sport. He was formerly the Head of Academy Sports Science and Strength & Conditioning at Cardiff City Football Club, and an interim Sports Scientist for the Welsh FA. He also has a master’s degree in strength and conditioning and is a NSCA certified strength and conditioning coach.

He is also the chief editor of the Performance Digest – a monthly review of the latest sports performance research.