Efficacy of the Transition of the Foot Strike Pattern From Rearfoot to Midfoot or Forefoot During Running on Pain and Disability in Cadets With Chronic Musculoskeletal Pain

A total of 81 participants will be enrolled in the study, randomized and allocated to one of the following three groups Usual Treatment Group: This group will perform standard physiotherapeutic treatment performed at the Naval School. This treatment consists of the application of conventional TENS whose parameters are: alternating current, rectangular pulse, pulse duration 100μs, frequency of 100Hz for 20 minutes. Laser therapy with an energy of 5 J at each point, irradiation area of 1cm², irradiation time of 20 seconds, 30 repetitions and total time of 10 minutes.

4.4.3 Transition from the Rearfoot to the Forefoot and Midfoot Group: Participants in this group will perform a training aimed at the transition of foot strike pattern from the rearfoot to the forefoot and midfoot progressively. Initially a ten-minute race will be held at a comfortable warm-up speed. Then the participants in this group will run continuously at the usual treadmill speed for thirty minutes in a 12-week progressive training program. See below: Week 1: 1min of barefoot running + 29 min of shod running Week 2: 2min of barefoot running + 28 min of shod running Week 3: 3min of barefoot running + 27 min of shod running Week 4: 5min of barefoot running + 25 min of shod running Week 5: 1min of barefoot running + 3 min of shod running (repeat 7 times) + 2 finals minuntes shod running Week 6: 1min of barefoot running +3 min of shod running (repeat 10 times) Week 7: 1min of barefoot running +1 min of shod running (repeat 15 times) Week 8: 10 min continuous of barefoot running + 20 min continuous of shod running Week 9: 15 min continuous of barefoot running + 15 min continuous of shod running Week 10: 20 min continuous of barefoot running + 10 min continuous of shod running Week 11: 25 min continuous of barefoot running + 5 min continuous of shod running Week 12: 30 min continuous of barefoot running Participants will receive verbal command "Avoid touching first with heel on the treadmill" and "Try to touch first with the middle region of the foot on the treadmill". If necessary, the investigator will provide additional feedback with verbal details about the foot strike pattern. During the first eight sessions continuous feedback will be given. In the last four sessions, feedback will be gradually removed. At the end of each session, participants will be asked a question about the naturalness of running the new foot touch pattern on the ground. A scale from 0 to 10 will be used, where 0 means "very difficult to perform / unnatural standard" and 10 indicates "easy / natural" pattern. The perception of pain will also be evaluated with the numerical scale of pain of 11 points (0 to 10), where 0 means "no pain" and 10 "the greatest pain possible". Weekly participants will receive visual feedback through slow-motion footage of their footfall during the race, along with investigator guidance on the new tread pattern. In addition to the treadmill transition protocol, this group will have free access to the standard physiotherapeutic treatment performed at the Naval School during and after the study.

Muscle Strengthening Group: The participants of this group will perform muscle strengthening exercises for trunk and lower limbs divided into four phases of three weeks each, following the protocol adapted from Esculier et al. (Esculier et al., 2017) The total period of the program strength will be 12 weeks. Elastos® elastic bands of weak, medium and strong intensity will be used to provide progression to the exercises. The exercises will be supervised by two investigators.

1. A Phase 1 will consist of four exercises:

I. Participant lying sideways, raise the upper leg while lightly pushing it back. Hold position. The exercise should be performed on both sides of the body 2 times a week. In the first week, 2 sets with 10 repetitions and permanence time of 5 seconds, with progression in the following weeks to 15 repetitions of 10 seconds. An elastic band will be worn around the legs at the ankles.