inclusion rate too low

This randomized controlled trial aims to explore the effect of a foot strengthening protocol on toe flexion strength, foot deformation and morphology as well as kinetics during sprinting, cutting and jumping in healthy athletes (18-40 completed years). The study consists of a 4 weeks control period, followed by 8 weeks intervention period and 4 weeks follow up

During the first period participants are unaware of their allocation, while in the intervention period they will be allocated to a train intervention or a control group (habits maintenance). The primary outcome is the toes maximal voluntary isometric plantarflexion. The treatment effectiveness estimand is the same as in a pretest-posttest case control study, considering the end of the control period as pre-point. An estimation of the individual variability in response to the treatment will be provided.

Inclusion criteria :

• To be affiliated in the federation of one of the following sports : soccer, handball, rugby, basketball or track and field;
• To practice their respective sport more than two times per week;
• Be affiliated or beneficiary of a social security insurance;
• Having freely given their written consent after having been informed of the purpose, the procedure and the potential risks involved.
• Licensed in a tennis club (FFT) and in a volleyball club (FFVolley)

Exclusion criteria :

• Use of pharmacological therapy to match gander identity;
• Have an abnormal range of motion of the toes and/or ankle;
• Have any kind of ankle or foot pain (self-defined and self-reported by the FAAM questionnaire) in the previous 6 months;
• Have a previous injury or surgery of the lower limb in the previous 6 months;
• Have a neurological or vestibular deficit that may affect walking or balance (lumbar-sacral radiculopathy, peripheral nerve pathology, Marfan or Eehlers-Danlos syndrome, etc.);
• Have contraindication to neuromuscular electrical stimulation (pacemaker, seizure disorders, pregnancy);
• Have a previous foot strengthening experience in the past 6 months for at least 2 weeks and more than one session per week;
• Participate at the same time in another medical interventional experiment or have participated in such a study in the 30 days preceding this study;
• Being unable to understand the purpose and conditions of the study, and to give consent;
• Being deprived of liberty or under guardianship.

The RCT is divided into 3 distinct periods (see study diagram in Appendix 1): a 4-week control period, an 8-week intervention period and a 4-week follow-up period. This 3-period experimental design was designed to was designed to reduce various methodological biases