# Experimental methodology for identifying an acceptable range of E-trekking cycling postures

Corentin Deribreux, Alejandra Polanco, Junfeng Peng

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Corentin Deribreux, Alejandra Polanco, Junfeng Peng. Experimental methodology for identifying an acceptable range of E-trekking cycling postures. Multidisciplinary Biomechanics Journal, 2025, 50th congress of the.., 10.46298/mbj.16255. hal-05191810v2

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Distributed under a Creative Commons Attribution 4.0 International License
# Experimental methodology for identifying an acceptable range of E-trekking cycling postures

Corentin Deribreux*, Alejandra Polanco, Junfeng Peng

Decathlon Sportslab, France, Lille

* Corresponding author: corentin.deribreux@decathlon.com

Received date: 03/04/2025

Accepted date: 27/06/2025

Publication date: 27/10/2025

**Keywords:** electric trekking cycling, acceptable posture, experimental methodology

© 2025 The Authors

Licence CC-BY 4.0

Published by Société de Biomécanique

## 1. Introduction

Worldwide, over 10 million individuals practice trekking cycling. An improper position on the bike can lead to pain, injury, decreased performance or in the worst case, stopping the practice. Numerous studies focused on optimizing bike fit for road cycling, addressing issues of discomfort and performance (Priego Quesada, 2019; Miraj, 2024). However, the specific demands of electric trekking bike use, characterized by varied terrain and extended durations, remain largely unexplored. In addition, designing a universally acceptable positional range for trekking cycling is challenged by inter-individual variability in morphology and sensory preferences (ISO 9241-210:2019). This study aims to determine the acceptable range of postures focused on the upper body (i.e., trunk and trunk-to-arm angle) for electric trekking bike cyclists, inspired by the work of Wang and Peng, (2023) who developed a human body model for assisting in electric bike design.

## 2. Methods

Individual rider perceptions of a defined set of postures were assessed. Posture acceptability ranges were then established by compiling the collective evaluations. For this, the tested postures and the riders perceptions were measured.

### 2.1 Subjects and procedure

Thirty riders (22 males, 8 females, height: 178,8±7,6 cm) with experience in the use of electric bikes on trails and touring participated in the study.

Three distinct postures per subject were defined, chosen from a pre-test to represent trekking cycling's range, ensuring they were sufficiently different. While all subjects tested the same bike configurations for the upper body, individual body characteristics led to unique postures for each rider. Two bikes (Decathlon, Original 920E, sizes: M/L) were used. The upper body configurations were defined through a 90mm stem variation. The saddle height was set from an initial setting following Silberman et al. (2005) recommendation (i.e., 0.883*inseam) and allowing each rider to adjust it as preferred.

The tests consisted of traveling for 30 minutes on a 6,5 km loop on off-road category surface (with a 20 m elevation gain). Each participant performed the test on each posture in a randomized order.

### 2.2 Measurements

Anthropometric measurements were collected (i.e., stature, inseam, arm length) to set the bike size and saddle settings.

The posture was measured from a lateral picture, while the rider was static on the bike, looking forward, and with the left leg fully extended on the pedal.

Markers placed on the wrist, acromion and greater trochanter were used to locate the joint position and compute the upper body posture. Trunk and trunk-to-arm angles were defined (Wang & Peng, 2023) as the angle between the horizontal axis and the greater trochanter/shoulder line; and as the angle between the greater trochanter/shoulder line and the shoulder/wrist line.
Posture perception was assessed after each condition using a questionnaire. In this study, the answer to the question "How do you rate the position tested for your use of the E-trekking bike" with a 4 points likert scale answer: 'Not at all acceptable' (NA), 'Somewhat unacceptable' (SNA), 'Somewhat acceptable' (SA) and 'Completely acceptable' (CA), was used.

## 2.3 Data analysis

A repeated-measures ANOVA was done to examine the variations in trunk and trunk-to-arm angle across levels of acceptability. Tukey post-hoc comparisons were then utilized to pinpoint significant inter-group differences (p<0.05).

The proportion of acceptability and non-acceptability was calculated for various postural ranges (PR) regrouping NA with SNA and CA with SA. Several PR were randomly simulated until finding a PR leading to 85% of acceptable postures and less than 15% unacceptable postures.

## 3. Results and discussion

A significant positive association was observed between trunk angle and acceptability (p<0.01). Specifically, greater trunk extension angles correlated with higher acceptability ratings, ranging from a mean of 54.9° in the NA group to 71.8° in the CA group. Post-hoc Tukey tests (p<0.01) indicated that the NA and SNA groups did not differ significantly, but both differed significantly from the SA and CA groups, which also differed significantly from each other. Conversely, a significant negative association was identified for the trunk-to-arm angle and acceptability (p<0.01). Mean trunk-to-arm angle progressively decreased with increasing acceptability, from 60.8° in the NA group to 53.2° in the CA group.

Post-hoc Tukey tests indicated that the NA and SNA groups did not differ significantly, but both differed significantly from the SA and CA groups, which also differed significantly from each other. In essence, smaller arm-trunk angles were associated with higher ratings of acceptability. Using the ANOVA results, we simulated different PR to identify one respecting 85% of acceptability (CA/SA).

Figure 1 depicts the PR selected from the simulations, leading to 88% of acceptable postures and 12% of unacceptable postures.

The current findings agree with existing scientific literature, regarding the enhancement of comfort with

upright postures, in contrast to performance-driven position, commonly used in road cycling. As expected, it can be observed that the use of e-trekking bikes privileges upright upper body postures.

<figure><img src="image_2.png" /><figcaption>Figure 1. Circles representing tested postures: CA/SA in green and NA/SNA in red. Green box representing the selected PR.</figcaption></figure>

## 4. Conclusions

In this study, we proposed an experimental methodology which enabled us to identify an acceptable PR based on user perception for E-trekking cyclists. To ensure the ecological validity of these findings, it would be beneficial to examine and validate this PR through a longitudinal study with a wider participant cohort and during a longer period of time.

## Acknowledgements

We would like to thank Leo Bordaz who participated in the collection of experimental data.

## Conflict of Interest Statement

None.

## Contributor Roles

CD: Conceptualization, Methodology, Writing original draft; AP: Supervision, writing review & editing; JP: Methodology, Supervision, Writing - review & editing.

## Funding

This study was financed by Decathlon Rockrider.
References

Priego Quesada, J. I., Kerr, Z. Y., Bertucci, W. M., & Carpes, F. P. (2019). The association of bike fitting with injury, comfort, and pain during cycling: An international retrospective survey. *European journal of sport science, 19*(6), 842–849. https://doi.org/10.1080/17461391.2018.1556738

Miraj, M., Gupta, A., Kalra, S., Khanna, A., & Ajmera, P. (2024). Biomechanical and postural evaluation of optimal bike fit for non-traumatic injury prevention: a narrative review. *Journal of Musculoskeletal Research, 27*(4). https://doi.org/10.1142/S0218957724300023

Wang, X., & Peng, J. (2023). A simplified human body model for assisting electric bicycle design. *Digital Human Modeling and Applied Optimization, 76*(76). http://doi.org/10.54941/ahfe1003354

Silberman, M. R., Webner, D., Collina, S., & Shiple, B. J. (2005). Road bicycle fit. *Clinical Journal of Sport Medicine, 15*(4), 271–276. https://doi.org/10.1097/01.jsm.0000171255.70156.da