Using the Back Squat to Predict Lower Extremity Injuries

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This blog post is a part of a series where we summarise the current literature on anything health, fitness and well-being related. These are research articles that can give you a better insight into different ways that you can train your clients to get better results - faster. Be sure to sign up to our weekly newsletter to get the latest exclusive contents and offers.

Case, Knudson, and Downey (2020)

Notably, a key determinant of success for an athlete involves pre-habilitation to avoid 'downtime' during a competitive season. A successful injury prevention programme could reduce injury rates by 66% as stated by previous research. It's also noted that resistance training can elicit these preventive adaptations with the added benefit of increasing strength concurrently.

Strength and conditioning coaches have an arsenal of assessment tools and techniques to predict the likelihood of an athlete sustaining an injury in-season. For instance, body-weight screening tools are prevalent but research has shown mixed findings regarding its effectiveness. The conditions of such screening tools may not represent the physically challenging demands of the sport and may lead to a false diagnosis. A possible technique to better identify injuries may be through the use of maximal testing, such as the maximal isometric and kinetic strength test for the back and lower extremity (LE). A study mentioned in this paper indicated a 28, 35 and 30% lower risk of LE overuse injury, respectively, over a 4-year period.

Shifting the focus onto a more specific area, the authors suggested the use of the barbell back squat (BS) exercise with relative strength measures to predict injuries. It was indicated that a 1-repetition maximum (1RM) BS has shown high reliability and accurate measures of strength for the LE musculature with an intraclass correlation coefficient of 0.91–0.99. The authors included this protocol in their study with the hopes of determining any significant relationships between injury rates and BS relative strength (RS). They hypothesised that lower RS will increase the likelihood of sustaining an injury.

Method

• The study used a convenience sampling technique on a university's Division-I male American football, female softball and volleyball population. These sports included intense LE activity.
• Subjects were excluded if they were sat out for their first season, have missing data and didn't complete the test.
• Kickers were excluded on the basis of suggestions from other research due to the performance characteristics of the players.
• Pre-season: absolute 1RM was collected by certified strength and conditioning coaches.
• In-season: all LE injuries sustained during this period was recorded. It was discovered that 78% of the American football players had an LE injury with the women's sports reported an LE injury rate of 52%.

Results

Relative BS strength was significantly higher in athletes with no LE injuries during the competitive season.

Practical applications

This study suggested the use of the back squat exercise with relative strength measures to predict and prescribe injury prevention programmes. The population which it applies to involves intense lower extremity activity, e.g. football, rugby, etc.

It was indicated that higher risk of lower extremity injuries is possible if relative back squat strength is below 2.2 in men and 1.6 in women.

References

Case, M., Knudson, D., and Downey, D. (2020). Barbell Squat Relative Strength as an Identifier for Lower Extremity Injury in Collegiate Athletes. Journal of Strength and Conditioning Research, 34(5), pp. 1249-1253.