1.    Introduction
The foot plays a critical role in absorbing impact, maintaining dynamic and static balance, and transmitting propulsion forces during running. Running footwear design influences foot biomechanics and muscle activation, which can affect performance and injury risk. The five-finger shoe, categorized as a minimalist shoe, mimics barefoot conditions while providing slight protection and structure. Although studies have examined the effects of minimalist shoes on muscle activity and running biomechanics, findings are varied regarding its advantages and potential limitations. Given the need to evaluate the five-finger shoe’s influence on ankle-related muscle activation, this study investigates the electromyographic (EMG) activity in specific lower leg muscles during running in barefoot and five-finger shoe conditions among novice runners.
2.    Methods
This semi-experimental study involved 16 novice male runners aged 20–30 years. Inclusion criteria required a minimum of one year of running experience and no previous use of five-finger shoes. Exclusion criteria included unwillingness to continue participation, discomfort or pain during testing, or recent musculoskeletal or neurological injuries. After obtaining informed consent, participants’ personal information was recorded, and muscle activity data were collected using an 8-channel MegaWin electromyography (EMG) device. Electrodes were placed on the dominant leg’s medial gastrocnemius, lateral gastrocnemius, soleus, and tibialis anterior muscles following the SENIAM protocol. Two foot switches were installed on each participant’s foot to mark the stance and propulsion phases. Participants completed 20-meter runs at a controlled speed of 3 meters per second in both barefoot and five-finger shoe conditions. Each condition was randomly assigned, and data were collected in three trials for each condition. EMG signals were normalized to maximum voluntary isometric contractions (MVICs) and analyzed using a paired t-test to assess differences between conditions with significance set at p < 0.05.
3.    Results
Table 1 presents the EMG activity comparisons for the selected muscles between barefoot and five-finger shoe conditions. Notably, the tibialis anterior muscle showed significantly higher activation during the contact phase when running with five-finger shoes compared to barefoot (p = 0.001). Similarly, the soleus and medial gastrocnemius muscles exhibited increased activation during the propulsion phase in the five-finger shoe condition (p = 0.002 and p = 0.010, respectively). However, lateral gastrocnemius activity did not differ significantly between conditions (p > 0.05).

4.    Conclusion
This study demonstrated that five-finger shoes increased muscle activity in specific calf muscles during running. Higher tibialis anterior activation in the contact phase suggests an adaptation to the altered foot strike pattern, likely related to heel impact when wearing five-finger shoes. Lieberman et al. (2010) found that barefoot running encourages mid- or forefoot strikes, reducing dorsiflexion and tibialis anterior activity, while minimalist footwear like five-finger shoes allows slight heel strikes, necessitating greater tibialis anterior engagement. Increased soleus and medial gastrocnemius activation in the propulsion phase suggests that five-finger shoes may elicit a foot-strike pattern with greater ground contact duration, engaging calf muscles for enhanced propulsion and support.
Additionally, adaptation to new footwear can impact muscle activation as runners adjust to its unique structure and feel. Warne and Gruber (2017) highlighted that transitioning to minimalist footwear requires neuromuscular adaptation, potentially increasing muscle activity initially. Over time, this adaptation may strengthen lower leg muscles, leading to more efficient running mechanics. Future research should investigate long-term adaptations to five-finger shoes and their impact on muscle activation and running performance. This study’s findings suggest that five-finger shoes may be beneficial for novice runners, offering a muscle activation pattern closer to barefoot running but with added protection. This information can guide sports trainers, therapists, and footwear designers in developing training programs and footwear that enhance performance and reduce injury risk. The findings indicate that five-finger shoes elicit similar muscle activity to barefoot running, with notable increases in tibialis anterior, soleus, and medial gastrocnemius activation. This suggests five-finger shoes could be a viable option for novice runners, potentially aiding in muscle strengthening while providing foot protection. Further studies are recommended to explore long-term adaptations and injury prevention benefits associated with these shoes.
Ethical Considerations
Compliance with ethical guidelines
There were no ethical considerations to be addressed in this research.
Funding
This research did not receive any financial support from government, private, or non-profit organizations.
Authors' contributions
All authors contributed equally to preparing the article.
Conflicts of interest
The authors declare that there are no conflicts of interest associated with this article.