Effect of a Flexibility Program on the Extensibility of the Hamstrings and the Thoracic and Lumbar Spinal Curvatures

Effect of a Flexibility Program on the Extensibility of the Hamstrings and the Thoracic and Lumbar Spinal Curvatures

The goal of this clinical trial is to analyse the effect of an intervention program based on hamstring flexibility on the extensibility and curvatures of the spine in dancers.

Participants will be dance student with ten years of experience that will undergo a program of stretching four times per week during seven weeks, followed by a detraining period, and a retraining period of three weeks. There will be a pre-test, a post-test and two re-tests after the intervention.

The results will be compared with a control group of dancers that will not take part in the stretching program.

Four measurements were carried out, one before the intervention (pre-test), one after the first stretching programme (post-test), one after a short period of detraining (re-test 1) and the last one at the end of a second period of intervention (re-test 2), analysing the intra-group and inter-group differences for each of the dependent variables.

The sample components (n=61) were divided into two groups following a random distribution carried out by an external researcher. The intervention group (IG), which consisted of 31 dancers, underwent the hamstring stretching programme for a first period of 7 weeks and a second period of 3 weeks after a short period of detraining. The intervention consisted of static and dynamic stretching of the hamstring muscles 4 days per week. The control group (CG), composed of 30 dancers, did not perform the stretching programme. Both groups attended their practical classes in the conservatory. During the detraining period the dancers of both groups took a break from physical exercise.

The variables measured are hamstring extensibility and sagittal spine disposition and pelvic tilt.

The inclusion criteria were:

1. students enrolled for at least 18 ECTS credits at the High Conservatory of Dance;
2. previous experience of 10 years in dance;
3. practice dance at least 4 days a week;

(c) not suffer from any chronic pathology or at the time of the study; (d) not practising any other physical exercise apart from dance.

Exclusion criteria:

1. Not attending at least 80% of the practical sessions of the Conservatory throughout the programme;
2. being pregnant at the beginning of the study or getting pregnant during the development of the study;
3. having undergone surgery on the spine or hamstring musculature;
4. having suffered a hamstring injuries in the last year or during the study;
5. having structured spinal disorders;
6. having an injury at the time of the assessment that prevents her from taking the measurements;
7. stretching of the hamstring musculature outside the conservatory.