title: Effects of a Stretching Development and Maintenance Program on Hamstring Extensibility in Schoolchildren: A Cluster-Randomized Controlled Trial.
abstract: The main purpose of the present study was to examine the effects of a physical education-based stretching development and maintenance program on hamstring extensibility in schoolchildren. A sample of 150 schoolchildren aged 7-10 years old from a primary school participated in the present study (140 participants were finally included). The six classes balanced by grade were cluster randomly assigned to the experimental group 1 (n = 51), experimental group 2 (n = 51) or control group (n = 49) (i.e., a cluster randomized controlled trial design was used). During the physical education classes, the students from the experimental groups 1 and 2 performed a four-minute stretching program twice a week for nine weeks (first semester). Then, after a five-week period of detraining coinciding with the Christmas holidays, the students from the experimental groups 1 and 2 completed another stretching program twice a week for eleven weeks (second semester). The students from the experimental group 1 continued performing the stretching program for four minutes while those from the experimental group 2 completed a flexibility maintenance program for only one minute. The results of the two-way analysis of variance showed that the physical education-based stretching development program significantly improved the students' hamstring extensibility (p < 0.001), as well as that these gains obtained remained after the stretching maintenance program (p < 0.001). Additionally, statistically significant differences between the two experimental groups were not found (p > 0.05). After a short-term stretching development program, a physical education-based stretching maintenance program of only one-minute sessions twice a week is effective in maintaining hamstring extensibility among schoolchildren. This knowledge could help and guide teachers to design programs that allow a feasible and effective development and maintenance of students' flexibility in the physical education setting. Key pointsA physical education-based stretching maintenance program of only one-minute sessions twice a week is effective in maintaining hamstring extensibility among schoolchildren.A four-minute maintenance program shows similar effects that the one-minute maintenance program on hamstring extensibility among schoolchildren.Physical education teachers and other practitioners could carry out one-minute programs for a feasible and effective maintenance of students' flexibility.
authors.affiliation: Department of Physical Education and Sport, University of Granada , Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mayorga-Vega
authors.affiliation: Facultad de Ciencias de la Educación, Universidad de Málaga (UMA) , Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Merino-Marban
authors.affiliation: CEIP Virgen de Belén, Junta de Andalucía , Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Manzano-Lagunas
authors.affiliation: Faculty of Physical Education and Sport Sciences, University of Chihuahua , Mexico.
authors.forename: Humberto
authors.initials: H
authors.lastname: Blanco
authors.affiliation: Department of Physical Education and Sport, University of Granada , Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Viciana
keywords: Flexibility program; classic sit-and-reach test; flexibility maintaining; physical education setting; physical fitness; primary school children