• To evaluate the effects of a 32-weeks resistance and stretching training program applied in Physical Education classes on forward head and protracted shoulder Portuguese adolescents (15-17 years old).
• To evaluate on adolescents submitted to strength and stretching exercises the effects of a 16-week detraining period after the end of the intervention protocol.

A prospective, randomized and controlled study will be conducted over a 12 month period, with adolescents of two public secondary schools, in Lisbon.

At the beginning, a total of 275 adolescent students aged 15-17 years old will be evaluated with photogrammetry. The students will be screened by measuring the cervical (CV) and shoulder (SH) angle with photogrammetry. If the CV and SH angle were less than 50º and 52º respectively, the adolescent was considered to have forward head posture (FHP) and protracted shoulder (PS) and was selected to the study.

Participants will be excluded if their CV and SH angle was equal or higher than 50º and 52º respectively, if they had visual deficits, diagnosed balance disorders, musculoskeletal pathologies, such as a history of shoulder surgery, cervical or thoracic fracture, were non-ambulatory, displayed functional or structural scoliosis, or had excessive thoracic kyphosis.

After these the eligible students will be randomly assigned to the control or interventional group. The intervention group will begin a 32-week stretching and strengthening program to be performed in the last part of the Physical Education (PE) classes. The control group will only participate in the PE classes. Since the 32th week until the 48th week the experimental group will not follow the interventional training program and both groups will only participate in PE classes.

The program will be constituted by four strengthening exercises and three stretching exercises and is designed based on the assumption that the use of therapeutic exercise is effective in the correction of specific neck and shoulder postures. The training exercise protocol will be designed for the correction of the FHP and PS, targeting to the selective activation of lower trapezius, middle trapezius and rhomboids, to the lengthening of the pectoralis major, pectoralis minor and sternocleidomastoid and to the improvement of the deep cervical flexor function This program is going to be applied in the last 15-20 minutes of each PE class, twice a week, with the supervision and help of the PE teacher.

The postural assessment of the groups will be performed in the beginning and after 36 and 48-weeks intervention period.

Inclusion Criteria:

adolescents with 15-17 years old with cervical angle lower than 50º and the shoulder angle lower than 52º

Exclusion Criteria:

Participants were excluded if their CV and SH angle was equal or higher than 50º and 52º respectively, if they had visual deficits, diagnosed balance disorders, musculoskeletal pathologies, such as a history of shoulder surgery, cervical or thoracic fracture, were non-ambulatory, displayed functional or structural scoliosis, or had excessive thoracic kyphosis.