The role of individual muscle-tendon characteristics for running shoe performance enhancement

Background.
Running performance is right now at a level never seen before and these performances are widely believed to be due to innovations in running shoe design. The shoes have a stiff, carbon fibre plate inserted along the length of the shoe in the midsole. Various studies have shown that running economy and various biomechanical indicators of performance are significantly improved when elite runners run in these shoes. Although some characteristics of the shoes have been suggested to underlie these improvements, the actual energy returning effects have not been mechanically tested. Furthermore, individual differences in being able to utilise such effects have not been studied.

Questions.
Previous studies have investigated shoe effects during running. However, inter-individual variations in the magnitude of the running economy effects indicate that we do not know what isolated energy return benefits the shoes themselves possess. We are therefore developing a test protocol to determine these as base data for the experimental studies. This testing protocol will be used by World Athletics for establishing rules for eligible shoes. Individual global data (height, weight, gender etc) and individual muscle tendon parameters (length, crossectional area, force, stiffness etc) will be used to characterise each runner. The importance of these individual characteristics will then be determined relative to biomechanical and physiological performance.

Schedule.
The shoe testing protocol work is at present underway and will be completed in the beginning of this project. The shoes used in the study will then be tested: with this protocol. The determination of individual participant characteristics will be followed by the biomechanical and physiological experimental work. All data collection and analysis and article writing is expected to be finished in 2022.

Importance.
This will be the first time the relationship between shoe effects (rather than simple shoe construction), individual global and muscle-tendon characteristics and performance will be ascertained, which is vital for understanding how individuals achieve performance enhancing effects from the newly developed shoes. This will be useful for athletes and trainers in being able to adapt for more efficient use of the new shoe technology. On a global scale it is imperative information for World Athletics and national athletics governing bodies in providing rules and guidelines ensuring fair competition.