What is normative data?
Normative data in sports science exists as a collection of standardised performance metrics derived from unique diagnostic tools, often from a given sample of individuals within a population. These norms often serve as standardised benchmarks useful as reference points to interpret an individual's test scores. It is important that normative data is labelled by test type, equipment used, and population assessed in order to maintain a suitable level of comparability when applied to specific groups.
Why is normative data important?
Without an understanding of what “normal” is, an individual’s test score becomes redundant and very difficult to interpret. There are several reasons why normative data is important to gather:
- Benchmarking and performance comparison
- Informing training prescription
- Progress monitoring
- Injury incidence
- Equipment validity
Benchmarking and Performance Comparison
Whether it be comparing individuals within the same squad, or teams across a variety of levels within a sport, normative data can provide a unique insight into average scores for a specific population, and whether they are better or worse than expected or required. By establishing what constitutes average, below-average, and above-average strength levels for specific demographics (age, gender, sport, etc.), sports scientists, physiotherapists and coaches can accurately determine where an athlete sits. When comparing an individual's scores to the norm, we are able to gain a greater understanding of their strengths and weaknesses that impact their performance potential. This can provide useful information for instances such as talent identification, selection, injury risk and training prescription.
Informing training prescription
Utilising test data enables for the creation of individualised training programmes, tailored to further enhance an individual’s strengths and address their weaknesses. In sport, we know that specific physical qualities are important, and can differ between position and level of play. Although a well programmed generic strength and conditioning programme can benefit many, a one-size-fits-all approach will often have an earlier expiry date Therefore, utilising normative data can allow us to better inform training for each individual within a group and maximise their training adaptation potential.
Progress monitoring
Once baseline scores have been set and programmes written, it is important to be able to reevaluate an individual’s status in response to a period of training. This will enable practitioners and athletes to undergo reflective practice to better understand the efficacy of the prescribed work. Without prior information on baselines and normative data, it can be difficult to understand whether progress has been made or not, and how much progress is good progress. For instance, if an athlete’s strength metrics have improved yet still remain substantially below the population norm, it is evident that further efforts must be made to continue to improve.
Injury incidence
Normative data is invaluable during times of rehabilitation in sport. Having pre-existing knowledge on (a) an athlete’s pre-injury condition, and (b) the population norm can be of extreme benefit to guide tricky rehabilitation programmes. Without prior knowledge of this, or knowing what is “normal” it becomes hard for practitioners to have confidence in the physical status of their athletes upon return to sport. Post-injury, athletes can then be assessed to determine whether they have returned to their pre-injury level, or better still surpassed it, and whether they sit about the population norm for specific physical qualities relating to the injury.
Equipment validity
Finally, normative data sets can provide practitioners with information on the suitability of a piece of equipment for a desired use. For example, if an isometric strength testing product is built to enable athletes to produce high amounts of force, it’s likely that it is well suited for such use. However, if low levels of force are able to be generated vs. other counterparts, questions could be asked on it’s appropriateness.
Interestingly, the Hip Extension Bench (HEB), a measure of maximal isometric hip extension force, has been compared to the popular “Iso-Hip” movement often utilised with force plates. When comparing force output alone, the HEB comes up as huge trumps, producing up to and above 3 x the amount of force that the Iso-Push does (see below).
Hip Extension Bench normative data
Football / soccer
HEB-60 - Allometric scaling (N/kg0.67)
*60° hip flexion angle
HEB-15 - Allometric scaling (N/kg0.67)
*15° hip flexion angle
